Oral and maxillofacial surgery with computer-assisted navigation system.

Science.gov (United States)

Kawachi, Homare; Kawachi, Yasuyuki; Ikeda, Chihaya; Takagi, Ryo; Katakura, Akira; Shibahara, Takahiko

2010-01-01

Intraoperative computer-assisted navigation has gained acceptance in maxillofacial surgery with applications in an increasing number of indications. We adapted a commercially available wireless passive marker system which allows calibration and tracking of virtually every instrument in maxillofacial surgery. Virtual computer-generated anatomical structures are displayed intraoperatively in a semi-immersive head-up display. Continuous observation of the operating field facilitated by computer assistance enables surgical navigation in accordance with the physician's preoperative plans. This case report documents the potential for augmented visualization concepts in surgical resection of tumors in the oral and maxillofacial region. We report a case of T3N2bM0 carcinoma of the maxillary gingival which was surgically resected with the assistance of the Stryker Navigation Cart System. This system was found to be useful in assisting preoperative planning and intraoperative monitoring.

Economic evaluation comparing intraoperative cone beam CT-based navigation and conventional fluoroscopy for the placement of spinal pedicle screws: a patient-level data cost-effectiveness analysis.

Science.gov (United States)

Dea, Nicolas; Fisher, Charles G; Batke, Juliet; Strelzow, Jason; Mendelsohn, Daniel; Paquette, Scott J; Kwon, Brian K; Boyd, Michael D; Dvorak, Marcel F S; Street, John T

2016-01-01

Pedicle screws are routinely used in contemporary spinal surgery. Screw misplacement may be asymptomatic but is also correlated with potential adverse events. Computer-assisted surgery (CAS) has been associated with improved screw placement accuracy rates. However, this technology has substantial acquisition and maintenance costs. Despite its increasing usage, no rigorous full economic evaluation comparing this technology to current standard of care has been reported. Medical costs are exploding in an unsustainable way. Health economic theory requires that medical equipment costs be compared with expected benefits. To answer this question for computer-assisted spinal surgery, we present an economic evaluation looking specifically at symptomatic misplaced screws leading to reoperation secondary to neurologic deficits or biomechanical concerns. The study design was an observational case-control study from prospectively collected data of consecutive patients treated with the aid of CAS (treatment group) compared with a matched historical cohort of patients treated with conventional fluoroscopy (control group). The patient sample consisted of consecutive patients treated surgically at a quaternary academic center. The primary effectiveness measure studied was the number of reoperations for misplaced screws within 1 year of the index surgery. Secondary outcome measures included were total adverse event rate and postoperative computed tomography usage for pedicle screw examination. A patient-level data cost-effectiveness analysis from the hospital perspective was conducted to determine the value of a navigation system coupled with intraoperative 3-D imaging (O-arm Imaging and the StealthStation S7 Navigation Systems, Medtronic, Louisville, CO, USA) in adult spinal surgery. The capital costs for both alternatives were reported as equivalent annual costs based on the annuitization of capital expenditures method using a 3% discount rate and a 7-year amortization period

Clinical results of free-hand pedicle screw placement by the palpation of lateral wall of pedicle (PLP) method for scoliosis surgery

International Nuclear Information System (INIS)

Oyama, Motohiko; Shimizu, Takachika; Fueki, Keisuke; Ino, Masatake; Toda, Naofumi; Tanouti, Tetu; Tatara, Yasunori; Manabe, Nodoka

2011-01-01

The purpose of this study was to evaluate the accuracy of thoracic pedicle screw (TPS) placement by the palpation of the lateral wall of the pedicle (PLP) method. The subjects of this study were 45 scoliosis patients. The accuracy of TPS placement was evaluated by postoperative CT. Of the 348 TPSs inserted, 26 (7.5%) breached the pedicle wall. Of the 26 misplaced screws, 20 were inserted on the wrong trajectory, and 6 were inserted at the wrong insertion point. The preoperative major Cobb angle averaged 70.4 deg in the group with pedicle perforation by the TPS, and 54.1 deg in the group with correct placement of the TPS (p=0.006). No intra- or post-operative complications developed as a result of the pedicle perforation. The PLP method is useful in deciding on the correct insertion point, but it is of no assistance in inserting screws along the correct trajectory. This, it will be necessary to improve the technique of determining the correct trajectory for the TPS. (author)

Surgical Navigation Technology Based on Augmented Reality and Integrated 3D Intraoperative Imaging

Science.gov (United States)

Elmi-Terander, Adrian; Skulason, Halldor; Söderman, Michael; Racadio, John; Homan, Robert; Babic, Drazenko; van der Vaart, Nijs; Nachabe, Rami

2016-01-01

Study Design. A cadaveric laboratory study. Objective. The aim of this study was to assess the feasibility and accuracy of thoracic pedicle screw placement using augmented reality surgical navigation (ARSN). Summary of Background Data. Recent advances in spinal navigation have shown improved accuracy in lumbosacral pedicle screw placement but limited benefits in the thoracic spine. 3D intraoperative imaging and instrument navigation may allow improved accuracy in pedicle screw placement, without the use of x-ray fluoroscopy, and thus opens the route to image-guided minimally invasive therapy in the thoracic spine. Methods. ARSN encompasses a surgical table, a motorized flat detector C-arm with intraoperative 2D/3D capabilities, integrated optical cameras for augmented reality navigation, and noninvasive patient motion tracking. Two neurosurgeons placed 94 pedicle screws in the thoracic spine of four cadavers using ARSN on one side of the spine (47 screws) and free-hand technique on the contralateral side. X-ray fluoroscopy was not used for either technique. Four independent reviewers assessed the postoperative scans, using the Gertzbein grading. Morphometric measurements of the pedicles axial and sagittal widths and angles, as well as the vertebrae axial and sagittal rotations were performed to identify risk factors for breaches. Results. ARSN was feasible and superior to free-hand technique with respect to overall accuracy (85% vs. 64%, P dimensions, except for vertebral body axial rotation, were risk factors for larger breaches when performed with the free-hand method. Conclusion. ARSN without fluoroscopy was feasible and demonstrated higher accuracy than free-hand technique for thoracic pedicle screw placement. Level of Evidence: N/A PMID:27513166

Patient Protection and Affordable Care Act; Exchange functions: standards for Navigators and non-Navigator assistance personnel; consumer assistance tools and programs of an Exchange and certified application counselors. Final rule.

Science.gov (United States)

2013-07-17

This final rule addresses various requirements applicable to Navigators and non-Navigator assistance personnel in Federally-facilitated Exchanges, including State Partnership Exchanges, and to non-Navigator assistance personnel in State Exchanges that are funded through federal Exchange Establishment grants. It finalizes the requirement that Exchanges must have a certified application counselor program. It creates conflict-of-interest, training and certification, and meaningful access standards; clarifies that any licensing, certification, or other standards prescribed by a state or Exchange must not prevent application of the provisions of title I of the Affordable Care Act; adds entities with relationships to issuers of stop loss insurance to the list of entities that are ineligible to become Navigators; and clarifies that the same ineligibility criteria that apply to Navigators apply to certain non-Navigator assistance personnel. The final rule also directs that each Exchange designate organizations which will then certify their staff members and volunteers to be application counselors that assist consumers and facilitate enrollment in qualified health plans and insurance affordability programs, and provides standards for that designation.

[Clinical application of three-dimensional O-arm navigation system in treating patients with dystrophic scoliosis secondary to neurofibromatosis type Ⅰ].

Science.gov (United States)

Liu, Z; Qiu, Y; Li, Y; Zhao, Z H; Wang, B; Zhu, F; Yu, Y; Sun, X; Zhu, Z Z

2017-03-01

Objective: To investigate the clinical outcomes and the accuracy of O-arm-navigation system assisted pedicle screw insertion in dystrophic scoliosis secondary to neurofibromatosis type Ⅰ(NF-1). Methods: A retrospective study was conducted in 41 patients with dystrophic NF-1-associated thoracic scoliosis who were surgically treated at Department of Orthopaedics, Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School between June 2012 and October 2014 with more than 18 months follow-up. The patients were then divided into two groups: 18 patients were under the assistance of O-arm-navigation-based pedicle screw insertion (O-arm group) and the remaining 23 patients' pedicle screws insertion were conducted by free-hand (free-hand group). The X-ray and CT were analyzed to investigate the correction rate and safety of pedicle insertion. t -test was used to analyze measurement data and χ(2) test was used to analyze accuracy of screw insertion between the two groups. Results: The mean coronal Cobb angle was 63.2°±8.7° in the O-arm group and 66.9°±7.4° in the free-hand group ( P >0.05), which was then corrected into 23.1°±6.8° and 30.2°±7.6°( t =2.231, P =0.031) after surgery respectively.Operation time was (265.0±70.3)minutes and estimated blood loss was (1 024±465)ml in the O-arm group. Operation time and estimated blood loss was (243.0±49.6)minutes and (1 228±521)ml respectively in the free-hand group, which had no significant difference between the two groups. However, the implant density was higher in the O-arm group than that in the free-hand group ((64.1±10.8)% vs .(44.3±15.3)%)( t =4.652, P =0.000). The O-arm group comprised 122 screws, of which 72.9% were excellent, 22.1% were good and 4.9% were bad. The free-hand group comprised 136 screws and 48.5% of them were excellent, 33.8% were good and 17.6% were bad.Accuracy of pedicle screw insertion was higher in the O-arm group than that in the free-hand group(χ(2

Navigating "Assisted Dying".

Science.gov (United States)

Schipper, Harvey

2016-02-01

Carter is a bellwether decision, an adjudication on a narrow point of law whose implications are vast across society, and whose impact may not be realized for years. Coupled with Quebec's Act Respecting End-of-life Care it has sharply changed the legal landscape with respect to actively ending a person's life. "Medically assisted dying" will be permitted under circumstances, and through processes, which have yet to be operationally defined. This decision carries with it moral assumptions, which mean that it will be difficult to reach a unifying consensus. For some, the decision and Act reflect a modern acknowledgement of individual autonomy. For others, allowing such acts is morally unspeakable. Having opened the Pandora's Box, the question becomes one of navigating a tolerable societal path. I believe it is possible to achieve a workable solution based on the core principle that "medically assisted dying" should be a very rarely employed last option, subject to transparent ongoing review, specifically as to why it was deemed necessary. My analysis is based on 1. The societal conditions in which have fostered demand for "assisted dying", 2. Actions in other jurisdictions, 3. Carter and Quebec Bill 52, 4. Political considerations, 5. Current medical practice. Leading to a series of recommendations regarding. 1. Legislation and regulation, 2. The role of professional regulatory agencies, 3. Medical professions education and practice, 4. Public education, 5. Health care delivery and palliative care. Given the burden of public opinion, and the legal steps already taken, a process for assisted-dying is required. However, those legal and regulatory steps should only be considered a necessary and defensive first step in a two stage process. The larger goal, the second step, is to drive the improvement of care, and thus minimize assisted-dying.

Pedicle streaking: A novel and simple aid in pedicle positioning in free tissue transfer

Directory of Open Access Journals (Sweden)

Aditya Aggarwal

2015-01-01

Full Text Available Introduction: The pedicle positioning in free tissue transfer is critical to its success. Long thin pedicles are especially prone to this complication where even a slight twist in the perforator can result in flap loss. Pedicles passing through the long tunnels are similarly at risk. Streaking the pedicle with methylene blue is a simple and safe method which increases the safety of free tissue transfer. Materials and Methods: Once the flap is islanded on the pedicle and the vascularity of the flap is confirmed, the pedicle is streaked with methylene blue dye at a distance of 6-7 mm. The streaking starts from the origin of the vessels and continued distally on to the under surface of flap to mark the complete course of the pedicle in alignment. The presence of streaking in some parts and not in rest indicates twist in the pedicle. Observation and Results: Four hundred and sixty five free flaps have been done at our centre in the last 5 years. The overall success rate of free flaps is 95.3% (22 free flap failures. There has not been a single case of pedicle twist leading to flap congestion and failure. Conclusion: This simple and novel method is very reliable for pedicle positioning avoiding any twist necessary for successful free tissue transfer.

Surgical Navigation Technology Based on Augmented Reality and Integrated 3D Intraoperative Imaging: A Spine Cadaveric Feasibility and Accuracy Study.

Science.gov (United States)

Elmi-Terander, Adrian; Skulason, Halldor; Söderman, Michael; Racadio, John; Homan, Robert; Babic, Drazenko; van der Vaart, Nijs; Nachabe, Rami

2016-11-01

A cadaveric laboratory study. The aim of this study was to assess the feasibility and accuracy of thoracic pedicle screw placement using augmented reality surgical navigation (ARSN). Recent advances in spinal navigation have shown improved accuracy in lumbosacral pedicle screw placement but limited benefits in the thoracic spine. 3D intraoperative imaging and instrument navigation may allow improved accuracy in pedicle screw placement, without the use of x-ray fluoroscopy, and thus opens the route to image-guided minimally invasive therapy in the thoracic spine. ARSN encompasses a surgical table, a motorized flat detector C-arm with intraoperative 2D/3D capabilities, integrated optical cameras for augmented reality navigation, and noninvasive patient motion tracking. Two neurosurgeons placed 94 pedicle screws in the thoracic spine of four cadavers using ARSN on one side of the spine (47 screws) and free-hand technique on the contralateral side. X-ray fluoroscopy was not used for either technique. Four independent reviewers assessed the postoperative scans, using the Gertzbein grading. Morphometric measurements of the pedicles axial and sagittal widths and angles, as well as the vertebrae axial and sagittal rotations were performed to identify risk factors for breaches. ARSN was feasible and superior to free-hand technique with respect to overall accuracy (85% vs. 64%, P dimensions, except for vertebral body axial rotation, were risk factors for larger breaches when performed with the free-hand method. ARSN without fluoroscopy was feasible and demonstrated higher accuracy than free-hand technique for thoracic pedicle screw placement. N/A.

Tactile-Foot Stimulation Can Assist the Navigation of People with Visual Impairment

Directory of Open Access Journals (Sweden)

Ramiro Velázquez

2015-01-01

Full Text Available Background. Tactile interfaces that stimulate the plantar surface with vibrations could represent a step forward toward the development of wearable, inconspicuous, unobtrusive, and inexpensive assistive devices for people with visual impairments. Objective. To study how people understand information through their feet and to maximize the capabilities of tactile-foot perception for assisting human navigation. Methods. Based on the physiology of the plantar surface, three prototypes of electronic tactile interfaces for the foot have been developed. With important technological improvements between them, all three prototypes essentially consist of a set of vibrating actuators embedded in a foam shoe-insole. Perceptual experiments involving direction recognition and real-time navigation in space were conducted with a total of 60 voluntary subjects. Results. The developed prototypes demonstrated that they are capable of transmitting tactile information that is easy and fast to understand. Average direction recognition rates were 76%, 88.3%, and 94.2% for subjects wearing the first, second, and third prototype, respectively. Exhibiting significant advances in tactile-foot stimulation, the third prototype was evaluated in navigation tasks. Results show that subjects were capable of following directional instructions useful for navigating spaces. Conclusion. Footwear providing tactile stimulation can be considered for assisting the navigation of people with visual impairments.

Usefulness and radiological evaluation of accuracy of innovative "Smart" hand technique for pedicle screw placement: an anatomical study.

Science.gov (United States)

Comert, Ayhan; Dogan, İhsan; Çaglar, Y Sukru

2017-11-01

The aim of this study is to use a smartphone application during pedicle screw placement navigation and examine the accuracy of this application on anatomical dry vertebrae model. 76 dry vertebrae were used for this study and pedicle entry points, projections of pedicle screw trajectory lines in lateral and superior aspect of vertebral body were identified and drawn for each vertebra bilaterally. In each position, all angulations were measured directly before the procedure manually. 152 pedicle screws were inserted as a simulation of screw placement with the guidance of angle-meter smart app. Accuracy of the method was tested according to the occurrence of bone penetration and angular deviation of the inserted screws was evaluated in computed tomography images. Mean deviation of pedicle screws of 76 pedicle screws in right side in horizontal plane was measured 2.30°±1.78°; in sagittal plane 2.17°±1.57° and in left side in horizontal plane 3.01°±1.83°; in sagittal plane 2.38°±1.68°. No bone penetration was occurred during 152 pedicle screw placements. According to the t-test results, there were significant differences between two groups in craniocaudal direction of the right side pedicle screws and in craniocaudal direction of left side pedicle screws. The free smartphone application presented here as angle-meter can be interpreted as a safe digital device for spinal instrumentation procedures. As a prototype of future pedicle screw fixation systems, it should be improved in terms of its feasibility and compatibility with screw probes. This may lead to apply mobile digital angle meter in spinal procedure.

Percutaneous Sacroiliac Screw Placement: A Prospective Randomized Comparison of Robot-assisted Navigation Procedures with a Conventional Technique

Directory of Open Access Journals (Sweden)

Jun-Qiang Wang

2017-01-01

Conclusions: Accuracy of the robot-assisted technique was superior to that of the freehand technique. Robot-assisted navigation is safe for unstable posterior pelvic ring stabilization, especially in S1, but also in S2. SI screw insertion with robot-assisted navigation is clinically feasible.

Image Guidance to Aid Pedicle Screw Fixation of a Lumbar Fracture-Dislocation Injury in a Toddler.

Science.gov (United States)

Houten, John K; Nahkla, Jonathan; Ghandi, Shashank

2017-09-01

Pedicle screw fixation of the lumbar spine in children age <2 years is particularly challenging, as successful cannulation of the small pedicle dimensions requires a high level of precision and there are no implants specifically designed for the infant spine. Image-guided navigation is commonly used in adult spinal surgery and may be particularly helpful for the placement of spinal screws in areas where the bony anatomy is small and/or anatomically complex, as in the upper cervical area. A 19-month-old female presented with a fracture-dislocation injury of L1-2. Intraoperative imaging using the O-arm multidimensional imaging system was networked to a workstation, and neuronavigation was used to place pedicle instrumentation with 3.5-mm-diameter polyaxial screws designed for posterior cervical fixation. At a 48-month follow-up, the patient was neurologically intact, demonstrated normal physical development, and was engaging in normal physical activity for her age. Radiographs obtained approximately 4 years postsurgery showed no evidence of loss for fixation. Image-guided placement of pedicle screws may be a useful aid in achieving accurate and safe fixation in the small dimensions of the infant spine. Copyright © 2017 Elsevier Inc. All rights reserved.

Are computer numerical control (CNC)-manufactured patient-specific metal templates available for posterior thoracic pedicle screw insertion? Feasibility and accuracy evaluation.

Science.gov (United States)

Kong, Xiangxue; Tang, Lei; Ye, Qiang; Huang, Wenhua; Li, Jianyi

2017-11-01

Accurate and safe posterior thoracic pedicle insertion (PTPI) remains a challenge. Patient-specific drill templates (PDTs) created by rapid prototyping (RP) can assist in posterior thoracic pedicle insertion, but pose biocompatibility risks. The aims of this study were to develop alternative PDTs with computer numerical control (CNC) and assess their feasibility and accuracy in assisting PTPI. Preoperative CT images of 31 cadaveric thoracic vertebras were obtained and then the optimal pedicle screw trajectories were planned. The PDTs with optimal screw trajectories were randomly assigned to be designed and manufactured by CNC or RP in each vertebra. With the guide of the CNC- or RP-manufactured PDTs, the appropriate screws were inserted into the pedicles. Postoperative CT scans were performed to analyze any deviations at entry point and midpoint of the pedicles. The CNC group was found to be significant manufacture-time-shortening, and cost-decreasing, when compared with the RP group (P  0.05). The screw positions were grade 0 in 90.3% and grade 1 in 9.7% of the cases in the CNC group and grade 0 in 93.5% and grade 1 in 6.5% of the cases in the RP group (P = 0.641). CNC-manufactured PDTs are viable for assisting in PTPI with good feasibility and accuracy.

Alternative radiation-free registration technique for image-guided pedicle screw placement in deformed cervico-thoracic segments.

Science.gov (United States)

Kantelhardt, Sven R; Neulen, Axel; Keric, Naureen; Gutenberg, Angelika; Conrad, Jens; Giese, Alf

2017-10-01

Image-guided pedicle screw placement in the cervico-thoracic region is a commonly applied technique. In some patients with deformed cervico-thoracic segments, conventional or 3D fluoroscopy based registration of image-guidance might be difficult or impossible because of the anatomic/pathological conditions. Landmark based registration has been used as an alternative, mostly using separate registration of each vertebra. We here investigated a routine for landmark based registration of rigid spinal segments as single objects, using cranial image-guidance software. Landmark based registration of image-guidance was performed using cranial navigation software. After surgical exposure of the spinous processes, lamina and facet joints and fixation of a reference marker array, up to 26 predefined landmarks were acquired using a pointer. All pedicle screws were implanted using image guidance alone. Following image-guided screw placement all patients underwent postoperative CT scanning. Screw positions as well as intraoperative and clinical parameters were retrospectively analyzed. Thirteen patients received 73 pedicle screws at levels C6 to Th8. Registration of spinal segments, using the cranial image-guidance succeeded in all cases. Pedicle perforations were observed in 11.0%, severe perforations of >2 mm occurred in 5.4%. One patient developed a transient C8 syndrome and had to be revised for deviation of the C7 pedicle screw. No other pedicle screw-related complications were observed. In selected patients suffering from pathologies of the cervico-thoracic region, which impair intraoperative fluoroscopy or 3D C-arm imaging, landmark based registration of image-guidance using cranial software is a feasible, radiation-saving and a safe alternative.

Nilai Rerata Vascular Pedicle Width, Vascular Pedicle-Cardiac Ratio Vascular Pedicle-Thoracic Ratio Orang Dewasa Normal Indonesia Studi di RS dr. Cipto Mangunkusomo

Directory of Open Access Journals (Sweden)

Rommy Zunera

2016-03-01

Full Text Available Vascular pedicle width (VPW adalah jarak tepi luar vena kava superior ke tepi luar arteri subklavia kiri. Pemeriksaan VPW di foto toraks bersifat non-invasif, cepat dan mudah untuk memprediksi hipervolemia.Penelitian ini bertujuan untuk mengetahui rerata nilai VPW orang dewasa normal Indonesia. VPW diukurdengan dua metode: pertama pengukuran VPW tunggal yang akurasinya terbatas di foto toraks digital karenarelatif tidak dipengaruhi faktor magnifikasi. Metode kedua untuk foto toraks nondigital yaitu pengukuranrasio:vascular pedicle-cardiac ratio (VPCR dan vascular pedicle-thoracic ratio (VPTR. Pengukuran serupadilakukan terhadap  topogram CT scan toraks AP terlentang dan CT scan toraks lalu dibandingkan akurasipengukuran di topogram dengan CT scan  toraks sebagai standar baku. Sampel terdiri atas 104 foto toraksPA subyek normal dan 103 CT scan  toraks subyek terpilih. Pada pemeriksaan toraks PA didapatkan rerata VPW 48,0±5,5mm, rerata VPCR 40,3±4,6%, dan rerata VPTR 17,2±1,7%. Pada pemeriksaan topogram CTscan didapatkan rerata VPW 50,3±6,2mm, rerata VPTR 45±5,1%, dan rerata VPTR 19,8±2,5%. Rerata VPWpada CT scan toraks 50,4±6,1mm. Pengukuran di foto toraks AP 10% lebih besar dibandingkan pada fototoraks PA dan pengukuranVPW di foto toraks terbukti memiliki akurasi  tinggi. Kata kunci: fototoraks, vascular pedicle width, vascular pedicle-cardiac ratio, vascular pedicle-thoracic ratio, hipervolemia.   The Mean Value of Vascular Pedicle Width, Vascular Pedicle-Cardiac Ratio,Vascular Pedicle-Thoracic Ratio of Normal Indonesian Adult Study In dr. Cipto Mangunkusomo Hospital Abstract Vascular pedicle width (VPW is the distance, from a perpendicular line at the takeoff point of the left subclavian artery off the aorta to the point at which the superior vena cava. Measurement of VPW on chestx-ray is relatively non-invasive, fast and easy technique as  hypervolemia predictor. The purpose of thisstudy is to know the mean VPW value of normal

Design of three-dimensional visualization based on the posterior lumbar pedicle screw fixation

Directory of Open Access Journals (Sweden)

Kai XU

2011-09-01

Full Text Available Objective To establish a three-dimensional visualization model of posterior lumbar pedicle screw fixation.Methods A patient with lumbar intervertebral disc hernia and another patient with compression fracture of lumbar vertebra were involved in the present study.Both patients underwent multi-slice spiral CT scan before and after lumbar pedicle screw fixation.The degree of preoperative vertebral compression,vertebral morphology before and after surgery,postoperative pedicle screw position,and decompression effects were observed.The original data of the multi-slice spiral CT were inputted into the computer.The three-dimensional reconstructed images of the lumbar and implanted screws were obtained using the software Amira 4.1 to show the three-dimensional shape of the lumbar vertebrae before and after surgery and the location of the implanted screws.Results The morphology and structure of the lumbar vertebrae before and after surgery and of the implanted screws were reconstructed using the digital navigation platform.The reconstructed 3D images could be displayed in multicolor,transparent,or arbitrary combinations.In the 3D surface reconstruction images,the location and structure of the implanted screws could be clearly observed,and the decompression of the spinal cord or nerve roots and the severity of the fracture and the compression of lumbar vertebrae could be fully evaluated.The reconstructed images before operation revealed the position of the vertebral pedicles and provided reference for intraoperative localization.Conclusions The three-dimensional computerized reconstructions of lumbar pedicle screw fixation may be valuable in basic research,clinical experiment,and surgical planning.The software Amira is one of the bases of three-dimensional reconstruction.

The pullout performance of pedicle screws

CERN Document Server

Demir, Teyfik

2015-01-01

This brief book systematically discusses all subjects that affect the pullout strength of pedicle screws. These screws are used in spinal surgeries to stabilize the spine. The holding strength of the pedicle screw is vital since loosening of the pedicle screws can cause revision surgeries. Once the pedicle screw is pulled out, it is harder to obtain same stabilization for the fused vertebrae. The book reviews the effect of screw designs, application techniques, cement augmentation, coating of the screw and test conditions on the pullout strength. The studies with finite element analysis were also included.

Computer-assisted navigational surgery enhances safety in dental implantology.

Science.gov (United States)

Ng, F C; Ho, K H; Wexler, A

2005-06-01

Dental implants are increasingly used to restore missing dentition. These titanium implants are surgically installed in the edentulous alveolar ridge and allowed to osteointegrate with the bone during the healing phase. After osseo-integration, the implant is loaded with a prosthesis to replace the missing tooth. Conventional implant treatment planning uses study models, wax-ups and panoramic x-rays to prefabricate surgical stent to guide the preparation of the implant site. The drilling into the alveolar ridge is invariably a "blind" procedure as the part of the drill in bone is not visible. Stereotactic systems were first introduced into neurosurgery in 1986. Since then, computer-assisted navigational technology has brought major advances to neuro-, midface and orthopaedic surgeries, and more recently, to implant placement. This paper illustrates the use of real-time computer-guided navigational technology in enhancing safety in implant surgical procedures. Real-time computer-guided navigational technology enhances accuracy and precision of the surgical procedure, minimises complications and facilitates surgery in challenging anatomical locations.

The freestyle pedicle perforator flap

DEFF Research Database (Denmark)

Gunnarsson, Gudjon Leifur; Jackson, Ian T; Westvik, Tormod S

2015-01-01

BACKGROUND: Perforating vessels are a consistent anatomical finding and well described in the current literature. Any skin flap can be raised on a subcutaneous pedicle as long as it contains at least one supplying perforator. Perforator flaps have been interlinked with microsurgery and generally...... not widely performed by the general plastic surgeons. The aim of this paper is to present the simplicity of pedicled perforator flap reconstruction of moderate-sized defects of the extremities and torso. METHODS: We retrospectively reviewed the charts of 34 patients reconstructed using 34 freestyle pedicled...... perforator flaps for moderate-sized defects of the truncus and extremities. We registered indications, flap size and localization, success rate, and complications. Most importantly, we describe a simple approach to the design of freestyle pedicled perforator flaps and elaborate on technical aspects...

Intelligent navigation and accurate positioning of an assist robot in indoor environments

Science.gov (United States)

Hua, Bin; Rama, Endri; Capi, Genci; Jindai, Mitsuru; Tsuri, Yosuke

2017-12-01

Intact robot's navigation and accurate positioning in indoor environments are still challenging tasks. Especially in robot applications, assisting disabled and/or elderly people in museums/art gallery environments. In this paper, we present a human-like navigation method, where the neural networks control the wheelchair robot to reach the goal location safely, by imitating the supervisor's motions, and positioning in the intended location. In a museum similar environment, the mobile robot starts navigation from various positions, and uses a low-cost camera to track the target picture, and a laser range finder to make a safe navigation. Results show that the neural controller with the Conjugate Gradient Backpropagation training algorithm gives a robust response to guide the mobile robot accurately to the goal position.

Pedicled perforator flaps

DEFF Research Database (Denmark)

Demirtas, Yener; Ozturk, Nuray; Kelahmetoglu, Osman

2009-01-01

Described in this study is a surgical concept that supports the "consider and use a pedicled perforator flap whenever possible and indicated" approach to reconstruct a particular skin defect. The operation is entirely free-style; the only principle is to obtain a pedicled perforator flap...... to reconstruct the defect. The perforators are marked with a hand-held Doppler probe and multiple flaps are designed. The appropriate flap is elevated after identifying the perforator(s). Dissection of the perforator(s) or complete incision of the flap margins are not mandatory if the flap is mobilized...... adequately to cover the defect. Defects measuring 3 x 3 cm up to 20 x 20 cm at diverse locations were successfully reconstructed in 20 of 21 patients with 26 flaps. Pedicled perforator flaps offer us reliable and satisfactory results of reconstruction at different anatomic territories of the body. It sounds...

An Outdoor Navigation Platform with a 3D Scanner and Gyro-assisted Odometry

Science.gov (United States)

Yoshida, Tomoaki; Irie, Kiyoshi; Koyanagi, Eiji; Tomono, Masahiro

This paper proposes a light-weight navigation platform that consists of gyro-assisted odometry, a 3D laser scanner and map-based localization for human-scale robots. The gyro-assisted odometry provides highly accurate positioning only by dead-reckoning. The 3D laser scanner has a wide field of view and uniform measuring-point distribution. The map-based localization is robust and computationally inexpensive by utilizing a particle filter on a 2D grid map generated by projecting 3D points on to the ground. The system uses small and low-cost sensors, and can be applied to a variety of mobile robots in human-scale environments. Outdoor navigation experiments were conducted at the Tsukuba Challenge held in 2009 and 2010, which is an open proving ground for human-scale robots. Our robot successfully navigated the assigned 1-km courses in a fully autonomous mode multiple times.

Liposuction-assisted four pedicle-based breast reduction (LAFPBR): A new safer technique of breast reduction for elderly patients.

Science.gov (United States)

La Padula, Simone; Hersant, Barbara; Noel, Warren; Meningaud, Jean Paul

2018-05-01

As older people increasingly care for their body image and remain active longer, the demand for reduction mammaplasty is increasing in this population. Only a few studies of reduction mammaplasty have specifically focussed on the outcomes in elderly women. We developed a new breast reduction technique: the Liposuction-Assisted Four Pedicle-Based Breast Reduction (LAFPBR) that is especially indicated for elderly patients. The aim of this paper was to describe the LAFPBR technique and to determine whether it could be considered a safer option for elderly patients compared to the superomedial pedicle (SMP) technique. A retrospective study included sixty-two women aged 60 years and over who underwent bilateral breast reduction mammaplasty. Thirty-one patients underwent LAFPBR and 31 patients were operated using the SMP technique. Complications and patient satisfaction in both groups were analysed. Patient satisfaction was measured using a validated questionnaire: the client satisfaction questionnaire 8 (CSQ-8). The LAFPBR technique required less operating time, and avoided significant blood loss. Six minor complications were observed in SMP patients. No LAFPBR women developed a procedure-related complication. Patient satisfaction was high with a mean score of 29.65 in LAFPBR patients and 28.68 in SMP patients. The LAFPBR is an easy procedure that appears safer than SMP and results in a high satisfaction rate in elderly women. Copyright © 2018 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Total knee arthroplasty with computer-assisted navigation: an analysis of 200 cases,

Directory of Open Access Journals (Sweden)

Marcus Vinicius Malheiros Luzo

2014-04-01

Full Text Available OBJECTIVE: to evaluate the results from surgery with computer-assisted navigation in cases of total knee arthroplasty.METHOD: a total of 196 patients who underwent total knee arthroplasty with computer-assisted navigation were evaluated. The extension and flexion spaces (gaps were evaluated during the operation and the alignment after the operation was assessed. The Knee Society Score (KSS questionnaire for assessing patient's function was applied preoperatively and postoperatively after a mean follow-up of 22 months.RESULTS: in all, 86.7% of the patients presented good alignment of the mechanical axis (less than 3◦ of varus or valgus in relation to the mechanical axis and 96.4% of the patients presented balanced flexion and extension gaps. Before the operation, 97% of the patients presented poor or insufficient KSS, but after the operation, 77.6% presented good or excellent KSS.CONCLUSION: the navigation system made it possible to achieve aligned and balanced implants, with notable functional improvement among the patients. It was found to be useful in assessing, understanding and improving knowledge in relation to performing arthroplasty procedures.

Minimally invasive scoliosis surgery assisted by O-arm navigation for Lenke Type 5C adolescent idiopathic scoliosis: a comparison with standard open approach spinal instrumentation.

Science.gov (United States)

Zhu, Weiguo; Sun, Weixiang; Xu, Leilei; Sun, Xu; Liu, Zhen; Qiu, Yong; Zhu, Zezhang

2017-04-01

OBJECTIVE Recently, minimally invasive scoliosis surgery (MISS) was introduced for the correction of adult scoliosis. Multiple benefits including a good deformity correction rate and fewer complications have been demonstrated. However, few studies have reported on the use of MISS for the management of adolescent idiopathic scoliosis (AIS). The purpose of this study was to investigate the outcome of posterior MISS assisted by O-arm navigation for the correction of Lenke Type 5C AIS. METHODS The authors searched a database for all patients with AIS who had been treated with either MISS or PSF between November 2012 and January 2014. Levels of fusion, density of implants, operation time, and estimated blood loss (EBL) were recorded. Coronal and sagittal parameters were evaluated before surgery, immediately after surgery, and at the last follow-up. The accuracy of pedicle screw placement was assessed according to postoperative axial CT images in both groups. The 22-item Scoliosis Research Society questionnaire (SRS-22) results and complications were collected during follow-up. RESULTS The authors retrospectively reviewed the records of 45 patients with Lenke Type 5C AIS, 15 who underwent posterior MISS under O-arm navigation and 30 who underwent posterior spinal fusion (PSF). The 2 treatment groups were matched in terms of baseline characteristics. Comparison of radiographic parameters revealed no obvious difference between the 2 groups immediately after surgery or at the final follow-up; however, the MISS patients had significantly less EBL (p self-image using the SRS-22 showed significantly higher scores in the MISS group (p = 0.013 and 0.046, respectively) than in the PSF group. Postoperative CT showed high accuracy in pedicle placement in both groups. No deep wound infection, pseudarthrosis, additional surgery, implant failure, or neurological complications were recorded in either group. CONCLUSIONS Minimally invasive scoliosis surgery is an effective and safe

Quantitative dual-energy CT for phantomless evaluation of cancellous bone mineral density of the vertebral pedicle: correlation with pedicle screw pull-out strength

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Wichmann, Julian L.; Booz, Christian; Bauer, Ralf W.; Kerl, J.M.; Fischer, Sebastian; Lehnert, Thomas; Vogl, Thomas J.; Khan, M.F. [University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Frankfurt am Main (Germany); Wesarg, Stefan [Fraunhofer IGD, Cognitive Computing and Medical Imaging, Darmstadt (Germany); Kafchitsas, Konstantinos [Spine Center, Asklepios Klinik Lindenlohe, Schwandorf (Germany)

2015-06-01

To evaluate quantitative dual-energy computed tomography (DECT) for phantomless analysis of cancellous bone mineral density (BMD) of vertebral pedicles and to assess the correlation with pedicle screw pull-out strength. Twenty-nine thoracic and lumbar vertebrae from cadaver specimens were examined with DECT. Using dedicated post-processing software, a pedicle screw vector was mapped (R1, intrapedicular segment of the pedicle vector; R2, intermediate segment; R3, intracorporal segment; global, all segments) and BMD was calculated. To invasively evaluate pedicle stability, pedicle screws were drilled through both pedicles and left pedicle screw pull-out strength was measured. Resulting values were correlated using the paired t test and Pearson's linear correlation. Average pedicle screw vector BMD (R1, 0.232 g/cm{sup 3}; R2, 0.166 g/cm{sup 3}; R3, 0.173 g/cm{sup 3}; global, 0.236 g/cm{sup 3}) showed significant differences between R1-R2 (P < 0.002) and R1-R3 (P < 0.034) segments while comparison of R2-R3 did not reach significance (P > 0.668). Average screw pull-out strength (639.2 N) showed a far stronger correlation with R1 (r = 0.80; P < 0.0001) than global BMD (r = 0.42; P = 0.025), R2 (r = 0.37; P = 0.048) and R3 (r = -0.33; P = 0.078) segments. Quantitative DECT allows for phantomless BMD assessment of the vertebral pedicle. BMD of the intrapedicular segment shows a significantly stronger correlation with pedicle screw pull-out strength than other segments. (orig.)

A spatial registration method for navigation system combining O-arm with spinal surgery robot

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Bai, H.; Song, G. L.; Zhao, Y. W.; Liu, X. Z.; Jiang, Y. X.

2018-05-01

The minimally invasive surgery in spinal surgery has become increasingly popular in recent years as it reduces the chances of complications during post-operation. However, the procedure of spinal surgery is complicated and the surgical vision of minimally invasive surgery is limited. In order to increase the quality of percutaneous pedicle screw placement, the O-arm that is a mobile intraoperative imaging system is used to assist surgery. The robot navigation system combined with O-arm is also increasing, with the extensive use of O-arm. One of the major problems in the surgical navigation system is to associate the patient space with the intra-operation image space. This study proposes a spatial registration method of spinal surgical robot navigation system, which uses the O-arm to scan a calibration phantom with metal calibration spheres. First, the metal artifacts were reduced in the CT slices and then the circles in the images based on the moments invariant could be identified. Further, the position of the calibration sphere in the image space was obtained. Moreover, the registration matrix is obtained based on the ICP algorithm. Finally, the position error is calculated to verify the feasibility and accuracy of the registration method.

Anatomical study of lumbar vertebral pedicle and adjacent neural structures

Directory of Open Access Journals (Sweden)

Matuoka Cláudia Maria

2002-01-01

Full Text Available For the evaluation of the Lumbar pedicle morphometry and its relation to the neural structures, 14 male adult cadavers were dissected, and the size of the lumbar pedicle was assessed by measuring its sagittal and transversal diameter. It was found that the size of the pedicle increases from L2 to L5, both in the sagittal and transversal diameter, the first bigger. The relation of the lumbar pedicle to the neural structures was evaluated by measuring the distance between dura-mater and the pedicle medial area, the distance between the most distal area of the pedicle and the nerve root that appears under it, and , to obtain in an indirect way, the distance between the pedicle apex and the nerve root that appears over it. The acquired results showed that the distance between the most distal area of the pedicle and the nerve root that appears under it, and the distance between the pedicle medial area and dura-mater, do not increase from L2 to L5, and they are in average 1,98 and 3,02 respectively. The distance between the pedicle apex and the nerve root that appears over it, increases from L2 to L5, varying from 13,64 in L2 to 21,62 in L5. The location of the spinal ganglion in relation to the pedicle has also been found, and 87% of the spinal ganglions are located in the foraminal zone.

Evaluation of an omental pedicle extension technique in the dog.

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Ross, W E; Pardo, A D

1993-01-01

A two-step omental pedicle extension technique was performed on 10 dogs. Step 1 of the pedicle extension involved release of the dorsal leaf of the omentum from its pancreatic attachment, whereas step 2 consisted of an inverse L-shaped incision to double the length of the pedicle. The pedicle dimensions were measured and the distance reached when extended toward the hind limb, forelimb, and the muzzle recorded after each stage of the procedure. The vascular patency of the pedicle was determined by intravenous injection of fluorescein dye after the second stage of omental extension. Mean pedicle lengths were 44.5 cm with the first stage of extension and 82.0 cm after full extension. The mean width at the caudal extent of the pedicles after dorsal and full extension was 30.4 cm and 17.2 cm, respectively. Eight of the 10 pedicles were patent after full extension. The fully extended omental pedicles reached and, in most cases, extended beyond the distal extremities and the muzzle. The findings in this study suggest that the canine omentum can be extended to any part of the body without being detached from its vascular supply.

Simple New Screw Insertion Technique without Extraction for Broken Pedicle Screws.

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Kil, Jin-Sang; Park, Jong-Tae

2018-05-01

Spinal transpedicular screw fixation is widely performed. Broken pedicle screw rates range from 3%-7.1%. Several techniques have been described for extraction of broken pedicle screws. However, most of these techniques require special instruments. We describe a simple, modified technique for management of broken pedicle screws without extraction. No special instruments or drilling in an adjacent pedicle are required. We used a high-speed air drill with a round burr. With C-arm fluoroscopy guidance, the distal fragment of a broken pedicle screw was palpated using free-hand technique through the screw entry hole. A high-speed air drill with a round burr (not a diamond burr) was inserted through the hole. Drilling began slowly and continued until enough space was obtained for new screw insertion. Using this space, we performed new pedicle screw fixation medially alongside the distal fragment of the broken pedicle screw. We performed the insertion with a previously used entry hole and pathway in the pedicle. The same size pedicle screw was used. Three patients were treated with this modified technique. New screw insertion was successful in all cases after partial drilling of the distal broken pedicle screw fragment. There were no complications, such as screw loosening, dural tears, or root injury. We describe a simple, modified technique for management of broken pedicle screws without extraction. This technique is recommended in patients who require insertion of a new screw. Copyright © 2017. Published by Elsevier Inc.

Navigation Problems in Blind-to-Blind Pedestrians Tele-assistance Navigation

OpenAIRE

Balata , Jan; Mikovec , Zdenek; Maly , Ivo

2015-01-01

International audience; We raise a question whether it is possible to build a large-scale navigation system for blind pedestrians where a blind person navigates another blind person remotely by mobile phone. We have conducted an experiment, in which we observed blind people navigating each other in a city center in 19 sessions. We focused on problems in the navigator’s attempts to direct the traveler to the destination. We observed 96 problems in total, classified them on the basis of the typ...

Augmented Reality Based Navigation for Computer Assisted Hip Resurfacing: A Proof of Concept Study.

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Liu, He; Auvinet, Edouard; Giles, Joshua; Rodriguez Y Baena, Ferdinando

2018-05-23

Implantation accuracy has a great impact on the outcomes of hip resurfacing such as recovery of hip function. Computer assisted orthopedic surgery has demonstrated clear advantages for the patients, with improved placement accuracy and fewer outliers, but the intrusiveness, cost, and added complexity have limited its widespread adoption. To provide seamless computer assistance with improved immersion and a more natural surgical workflow, we propose an augmented-reality (AR) based navigation system for hip resurfacing. The operative femur is registered by processing depth information from the surgical site with a commercial depth camera. By coupling depth data with robotic assistance, obstacles that may obstruct the femur can be tracked and avoided automatically to reduce the chance of disruption to the surgical workflow. Using the registration result and the pre-operative plan, intra-operative surgical guidance is provided through a commercial AR headset so that the user can perform the operation without additional physical guides. To assess the accuracy of the navigation system, experiments of guide hole drilling were performed on femur phantoms. The position and orientation of the drilled holes were compared with the pre-operative plan, and the mean errors were found to be approximately 2 mm and 2°, results which are in line with commercial computer assisted orthopedic systems today.

[Computer-assisted navigation in orthognathic surgery. Application to Le Fort I osteotomy.

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Benassarou, M; Benassarou, A; Meyer, C

2013-08-05

Computer-assisted navigation is a tool that allows the surgeon to reach intraoperatively a previously defined target. This technique can be applied to the positioning of bone fragments in orthognathic surgery. It is not used routinely yet because there are no specifically dedicated systems available on the market for this kind of surgery. The goal of our study was to describe the various systems that could be used in orthognathic surgery and to report our experience of computer-assisted surgery in the positioning of the maxilla during maxillomandibular osteotomies. Copyright © 2013. Published by Elsevier Masson SAS.

Adjacent-segment disease after thoracic pedicle screw fixation.

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Agarwal, Nitin; Heary, Robert F; Agarwal, Prateek

2018-03-01

OBJECTIVE Pedicle screw fixation is a technique widely used to treat conditions ranging from spine deformity to fracture stabilization. Pedicle screws have been used traditionally in the lumbar spine; however, they are now being used with increasing frequency in the thoracic spine as a more favorable alternative to hooks, wires, or cables. Although safety concerns, such as the incidence of adjacent-segment disease (ASD) after cervical and lumbar fusions, have been reported, such issues in the thoracic spine have yet to be addressed thoroughly. Here, the authors review the literature on ASD after thoracic pedicle screw fixation and report their own experience specifically involving the use of pedicle screws in the thoracic spine. METHODS Select references from online databases, such as PubMed (provided by the US National Library of Medicine at the National Institutes of Health), were used to survey the literature concerning ASD after thoracic pedicle screw fixation. To include the authors' experience at Rutgers New Jersey Medical School, a retrospective review of a prospectively maintained database was performed to determine the incidence of complications over a 13-year period in 123 consecutive adult patients who underwent thoracic pedicle screw fixation. Children, pregnant or lactating women, and prisoners were excluded from the review. By comparing preoperative and postoperative radiographic images, the occurrence of thoracic ASD and disease within the surgical construct was determined. RESULTS Definitive radiographic fusion was detected in 115 (93.5%) patients. Seven incidences of instrumentation failure and 8 lucencies surrounding the screws were observed. One patient was observed to have ASD of the thoracic spine. The mean follow-up duration was 50 months. CONCLUSIONS This long-term radiographic evaluation revealed the use of pedicle screws for thoracic fixation to be an effective stabilization modality. In particular, ASD seems to be less of a problem in the

Computer-assisted surgery: virtual- and augmented-reality displays for navigation during urological interventions.

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van Oosterom, Matthias N; van der Poel, Henk G; Navab, Nassir; van de Velde, Cornelis J H; van Leeuwen, Fijs W B

2018-03-01

To provide an overview of the developments made for virtual- and augmented-reality navigation procedures in urological interventions/surgery. Navigation efforts have demonstrated potential in the field of urology by supporting guidance for various disorders. The navigation approaches differ between the individual indications, but seem interchangeable to a certain extent. An increasing number of pre- and intra-operative imaging modalities has been used to create detailed surgical roadmaps, namely: (cone-beam) computed tomography, MRI, ultrasound, and single-photon emission computed tomography. Registration of these surgical roadmaps with the real-life surgical view has occurred in different forms (e.g. electromagnetic, mechanical, vision, or near-infrared optical-based), whereby the combination of approaches was suggested to provide superior outcome. Soft-tissue deformations demand the use of confirmatory interventional (imaging) modalities. This has resulted in the introduction of new intraoperative modalities such as drop-in US, transurethral US, (drop-in) gamma probes and fluorescence cameras. These noninvasive modalities provide an alternative to invasive technologies that expose the patients to X-ray doses. Whereas some reports have indicated navigation setups provide equal or better results than conventional approaches, most trials have been performed in relatively small patient groups and clear follow-up data are missing. The reported computer-assisted surgery research concepts provide a glimpse in to the future application of navigation technologies in the field of urology.

Traumatic Fracture of Thin Pedicles Secondary to Extradural ...

African Journals Online (AJOL)

sequelae, secondary to local mass effect. Our objective is to report a technical case report, illustrating a traumatic spinal injury with multiple pedicle fractures, secondary to atrophic lumbar pedicles as well as the diagnostic workup and surgical management of this problem. Posterior lumbar decompression, resection of the ...

Infection of PTFE mesh 15 years following pedicled TRAM flap breast reconstruction: mechanism and aetiology.

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Elfaki, A; Gkorila, A; Khatib, M; Malata, C M

2018-01-01

The pedicled transverse rectus abdominis myocutaneous (TRAM) flap procedure is still widely used for breast reconstruction. The repair of the flap harvest site in the transverse rectus abdominis muscle and sheath is often assisted by the use of prosthetic meshes. This decreases the risk of abdominal wall weakness and herniation but, being a foreign body, it also carries the risk of infection. In this report, we describe the case of a 63-year-old patient who, whilst receiving chemotherapy for metastatic breast cancer, presented with an infected polytetrafluoroethylene mesh 15 years after pedicled TRAM flap immediate breast reconstruction. This necessitated mesh removal to treat the infection. Following a thorough review of the English literature, this is the longest recorded presentation of an abdominal prosthetic mesh infection. The mechanism and aetiology of such a late complication are discussed.

Usability evaluation of augmented reality user interfaces in games and personal navigation assistants

OpenAIRE

Ivanec, Zorian

2017-01-01

This paper studies heuristic usability evaluation of user interfaces. The literature review distinguishes characteristics of augmented reality and smartphones, presents heuristic evaluation, PACMAD usability model, personal navigation assistants, video games, augmented reality and J. Nielsen usability heuristics. In research part, usability heuristics of related subject fields and design guidelines are combined. Created heuristics and control questionnaire are used for evaluation of augmented...

CT-MR image data fusion for computer assisted navigated neurosurgery of temporal bone tumors

International Nuclear Information System (INIS)

Nemec, Stefan Franz; Donat, Markus Alexander; Mehrain, Sheida; Friedrich, Klaus; Krestan, Christian; Matula, Christian; Imhof, Herwig; Czerny, Christian

2007-01-01

Purpose: To demonstrate the value of multi detector computed tomography (MDCT) and magnetic resonance imaging (MRI) in the preoperative work up of temporal bone tumors and to present, especially, CT and MR image fusion for surgical planning and performance in computer assisted navigated neurosurgery of temporal bone tumors. Materials and methods: Fifteen patients with temporal bone tumors underwent MDCT and MRI. MDCT was performed in high-resolution bone window level setting in axial plane. The reconstructed MDCT slice thickness was 0.8 mm. MRI was performed in axial and coronal plane with T2-weighted fast spin-echo (FSE) sequences, un-enhanced and contrast-enhanced T1-weighted spin-echo (SE) sequences, and coronal T1-weighted SE sequences with fat suppression and with 3D T1-weighted gradient-echo (GE) contrast-enhanced sequences in axial plane. The 3D T1-weighted GE sequence had a slice thickness of 1 mm. Image data sets of CT and 3D T1-weighted GE sequences were merged utilizing a workstation to create CT-MR fusion images. MDCT and MR images were separately used to depict and characterize lesions. The fusion images were utilized for interventional planning and intraoperative image guidance. The intraoperative accuracy of the navigation unit was measured, defined as the deviation between the same landmark in the navigation image and the patient. Results: Tumorous lesions of bone and soft tissue were well delineated and characterized by CT and MR images. The images played a crucial role in the differentiation of benign and malignant pathologies, which consisted of 13 benign and 2 malignant tumors. The CT-MR fusion images supported the surgeon in preoperative planning and improved surgical performance. The mean intraoperative accuracy of the navigation system was 1.25 mm. Conclusion: CT and MRI are essential in the preoperative work up of temporal bone tumors. CT-MR image data fusion presents an accurate tool for planning the correct surgical procedure and is a

History of Retractor Technologies for Percutaneous Pedicle Screw Fixation Systems.

Science.gov (United States)

Mobbs, Ralph J; Phan, Kevin

2016-02-01

Minimally invasive techniques aimed at minimizing surgery-associated risk and morbidity of spinal surgery have increased in popularity in recent years. Their potential advantages include reduced length of hospital stay, blood loss, and requirement for post-operative analgesia and earlier return to work. One such minimally invasive technique is the use of percutaneous pedicle screw fixation, which is paramount for promoting rigid and stable constructs and fusion in the context of trauma, tumors, deformity and degenerative disease. Percutaneous pedicle screw insertion can be an intimidating prospect for surgeons who have only been trained in open techniques. One of the ongoing challenges of this percutaneous system is to provide the surgeon with adequate access to the pedicle entry anatomy and adequate tactile or visual feedback concerning the position and anatomy of the rod and set-screw construct. This review article discusses the history and evolution of percutaneous pedicle screw retractor technologies and outlines the advances over the last decade in the rapidly expanding field of minimal access surgery for posterior pedicle screw based spinal stabilization. As indications for percutaneous pedicle screw techniques expand, the nuances of the minimally invasive surgery techniques and associated technologies will also multiply. It is important that experienced surgeons have access to tools that can improve access with a greater degree of ease, simplicity and safety. We here discuss the technical challenges of percutaneous pedicle screw retractor technologies and a variety of systems with a focus on the pros and cons of various retractor systems. © 2016 Chinese Orthopaedic Association and John Wiley & Sons Australia, Ltd.

Comparison of Expansive Pedicle Screw and Polymethylmethacrylate-Augmented Pedicle Screw in Osteoporotic Sheep Lumbar Vertebrae: Biomechanical and Interfacial Evaluations

OpenAIRE

Liu, Da; Zhang, Yi; Zhang, Bo; Xie, Qing-yun; Wang, Cai-ru; Liu, Jin-biao; Liao, Dong-fa; Jiang, Kai; Lei, Wei; Pan, Xian-ming

2013-01-01

BACKGROUND: It was reported that expansive pedicle screw (EPS) and polymethylmethacrylate-augmented pedicle screw (PMMA-PS) could be used to increase screw stability in osteoporosis. However, there are no studies comparing the two kinds of screws in vivo. Thus, we aimed to compare biomechanical and interfacial performances of EPS and PMMA-PS in osteoporotic sheep spine. METHODOLOGY/PRINCIPAL FINDINGS: After successful induction of osteoporotic sheep, lumbar vertebrae in each sheep were random...

Pedicle screw anchorage of carbon fiber-reinforced PEEK screws under cyclic loading.

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Lindtner, Richard A; Schmid, Rene; Nydegger, Thomas; Konschake, Marko; Schmoelz, Werner

2018-03-01

Pedicle screw loosening is a common and significant complication after posterior spinal instrumentation, particularly in osteoporosis. Radiolucent carbon fiber-reinforced polyetheretherketone (CF/PEEK) pedicle screws have been developed recently to overcome drawbacks of conventional metallic screws, such as metal-induced imaging artifacts and interference with postoperative radiotherapy. Beyond radiolucency, CF/PEEK may also be advantageous over standard titanium in terms of pedicle screw loosening due to its unique material properties. However, screw anchorage and loosening of CF/PEEK pedicle screws have not been evaluated yet. The aim of this biomechanical study therefore was to evaluate whether the use of this alternative nonmetallic pedicle screw material affects screw loosening. The hypotheses tested were that (1) nonmetallic CF/PEEK pedicle screws resist an equal or higher number of load cycles until loosening than standard titanium screws and that (2) PMMA cement augmentation further increases the number of load cycles until loosening of CF/PEEK screws. In the first part of the study, left and right pedicles of ten cadaveric lumbar vertebrae (BMD 70.8 mg/cm 3  ± 14.5) were randomly instrumented with either CF/PEEK or standard titanium pedicle screws. In the second part, left and right pedicles of ten vertebrae (BMD 56.3 mg/cm 3  ± 15.8) were randomly instrumented with either PMMA-augmented or nonaugmented CF/PEEK pedicle screws. Each pedicle screw was subjected to cyclic cranio-caudal loading (initial load ranging from - 50 N to + 50 N) with stepwise increasing compressive loads (5 N every 100 cycles) until loosening or a maximum of 10,000 cycles. Angular screw motion ("screw toggling") within the vertebra was measured with a 3D motion analysis system every 100 cycles and by stress fluoroscopy every 500 cycles. The nonmetallic CF/PEEK pedicle screws resisted a similar number of load cycles until loosening as the contralateral standard

SLAM algorithm applied to robotics assistance for navigation in unknown environments

Directory of Open Access Journals (Sweden)

Lobo Pereira Fernando

2010-02-01

Full Text Available Abstract Background The combination of robotic tools with assistance technology determines a slightly explored area of applications and advantages for disability or elder people in their daily tasks. Autonomous motorized wheelchair navigation inside an environment, behaviour based control of orthopaedic arms or user's preference learning from a friendly interface are some examples of this new field. In this paper, a Simultaneous Localization and Mapping (SLAM algorithm is implemented to allow the environmental learning by a mobile robot while its navigation is governed by electromyographic signals. The entire system is part autonomous and part user-decision dependent (semi-autonomous. The environmental learning executed by the SLAM algorithm and the low level behaviour-based reactions of the mobile robot are robotic autonomous tasks, whereas the mobile robot navigation inside an environment is commanded by a Muscle-Computer Interface (MCI. Methods In this paper, a sequential Extended Kalman Filter (EKF feature-based SLAM algorithm is implemented. The features correspond to lines and corners -concave and convex- of the environment. From the SLAM architecture, a global metric map of the environment is derived. The electromyographic signals that command the robot's movements can be adapted to the patient's disabilities. For mobile robot navigation purposes, five commands were obtained from the MCI: turn to the left, turn to the right, stop, start and exit. A kinematic controller to control the mobile robot was implemented. A low level behavior strategy was also implemented to avoid robot's collisions with the environment and moving agents. Results The entire system was tested in a population of seven volunteers: three elder, two below-elbow amputees and two young normally limbed patients. The experiments were performed within a closed low dynamic environment. Subjects took an average time of 35 minutes to navigate the environment and to learn how

Current trends in pedicle screw stimulation techniques: lumbosacral, thoracic, and cervical levels.

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Isley, Michael R; Zhang, Xiao-Feng; Balzer, Jeffrey R; Leppanen, Ronald E

2012-06-01

Unequivocally, pedicle screw instrumentation has evolved as a primary construct for the treatment of both common and complex spinal disorders. However an inevitable and potentially major complication associated with this type of surgery is misplacement of a pedicle screw(s) which may result in neural and vascular complications, as well as impair the biomechanical stability of the spinal instrumentation resulting in loss of fixation. In light of these potential surgical complications, critical reviews of outcome data for treatment of chronic, low-back pain using pedicle screw instrumentation concluded that "pedicle screw fixation improves radiographically demonstrated fusion rates;" however the expense and complication rates for such constructs are considerable in light of the clinical benefit (Resnick et al. 2005a). Currently, neuromonitoring using free-run and evoked (triggered) electromyography (EMG) is widely used and advocated for safer and more accurate placement of pedicle screws during open instrumentation procedures, and more recently, guiding percutaneous placement (minimally invasive) where the pedicle cannot be easily inspected visually. The latter technique, evoked or triggered EMG when applied to pedicle screw instrumentation surgeries, has been referred to as the pedicle screw stimulation technique. As concluded in the Position Statement by the American Society of Neurophysiological Monitoring (ASNM), multimodality neuromonitoring using free-run EMG and the pedicle screw stimulation technique was considered a practice option and not yet a standard of care (Leppanen 2005). Subsequently, the American Association of Neurological Surgeons/Congress of Neurological Surgeons (AANS/CNS) Joint Section on Disorders of the Spine and Peripheral Nerves published their "Guidelines for the Performance of Fusion Procedures for Degenerative Disease of the Lumbar Spine" (Heary 2005, Resnick et al. 2005a, Resnick et al. 2005b). It was concluded that the "primary

Extraction of user's navigation commands from upper body force interaction in walker assisted gait.

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Frizera Neto, Anselmo; Gallego, Juan A; Rocon, Eduardo; Pons, José L; Ceres, Ramón

2010-08-05

The advances in technology make possible the incorporation of sensors and actuators in rollators, building safer robots and extending the use of walkers to a more diverse population. This paper presents a new method for the extraction of navigation related components from upper-body force interaction data in walker assisted gait. A filtering architecture is designed to cancel: (i) the high-frequency noise caused by vibrations on the walker's structure due to irregularities on the terrain or walker's wheels and (ii) the cadence related force components caused by user's trunk oscillations during gait. As a result, a third component related to user's navigation commands is distinguished. For the cancelation of high-frequency noise, a Benedict-Bordner g-h filter was designed presenting very low values for Kinematic Tracking Error ((2.035 +/- 0.358).10(-2) kgf) and delay ((1.897 +/- 0.3697).10(1)ms). A Fourier Linear Combiner filtering architecture was implemented for the adaptive attenuation of about 80% of the cadence related components' energy from force data. This was done without compromising the information contained in the frequencies close to such notch filters. The presented methodology offers an effective cancelation of the undesired components from force data, allowing the system to extract in real-time voluntary user's navigation commands. Based on this real-time identification of voluntary user's commands, a classical approach to the control architecture of the robotic walker is being developed, in order to obtain stable and safe user assisted locomotion.

Navigation and Image Injection for Control of Bone Removal and Osteotomy Planes in Spine Surgery.

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Kosterhon, Michael; Gutenberg, Angelika; Kantelhardt, Sven Rainer; Archavlis, Elefterios; Giese, Alf

2017-04-01

In contrast to cranial interventions, neuronavigation in spinal surgery is used in few applications, not tapping into its full technological potential. We have developed a method to preoperatively create virtual resection planes and volumes for spinal osteotomies and export 3-D operation plans to a navigation system controlling intraoperative visualization using a surgical microscope's head-up display. The method was developed using a Sawbone ® model of the lumbar spine, demonstrating feasibility with high precision. Computer tomographic and magnetic resonance image data were imported into Amira ® , a 3-D visualization software. Resection planes were positioned, and resection volumes representing intraoperative bone removal were defined. Fused to the original Digital Imaging and Communications in Medicine data, the osteotomy planes were exported to the cranial version of a Brainlab ® navigation system. A navigated surgical microscope with video connection to the navigation system allowed intraoperative image injection to visualize the preplanned resection planes. The workflow was applied to a patient presenting with a congenital hemivertebra of the thoracolumbar spine. Dorsal instrumentation with pedicle screws and rods was followed by resection of the deformed vertebra guided by the in-view image injection of the preplanned resection planes into the optical path of a surgical microscope. Postoperatively, the patient showed no neurological deficits, and the spine was found to be restored in near physiological posture. The intraoperative visualization of resection planes in a microscope's head-up display was found to assist the surgeon during the resection of a complex-shaped bone wedge and may help to further increase accuracy and patient safety. Copyright © 2017 by the Congress of Neurological Surgeons

Intraoperative computed tomography with an integrated navigation system in stabilization surgery for complex craniovertebral junction malformation.

Science.gov (United States)

Yu, Xinguang; Li, Lianfeng; Wang, Peng; Yin, Yiheng; Bu, Bo; Zhou, Dingbiao

2014-07-01

This study was designed to report our preliminary experience with stabilization procedures for complex craniovertebral junction malformation (CVJM) using intraoperative computed tomography (iCT) with an integrated neuronavigation system (NNS). To evaluate the workflow, feasibility and clinical outcome of stabilization procedures using iCT image-guided navigation for complex CVJM. The stabilization procedures in CVJM are complex because of the area's intricate geometry and bony structures, its critical relationship to neurovascular structures and the intricate biomechanical issues involved. A sliding gantry 40-slice computed tomography scanner was installed in a preexisting operating room. The images were transferred directly from the scanner to the NNS using an automated registration system. On the basis of the analysis of intraoperative computed tomographic images, 23 cases (11 males, 12 females) with complicated CVJM underwent navigated stabilization procedures to allow more control over screw placement. The age of these patients were 19-52 years (mean: 33.5 y). We performed C1-C2 transarticular screw fixation in 6 patients to produce atlantoaxial arthrodesis with better reliability. Because of a high-riding transverse foramen on at least 1 side of the C2 vertebra and an anomalous vertebral artery position, 7 patients underwent C1 lateral mass and C2 pedicle screw fixation. Ten additional patients were treated with individualized occipitocervical fixation surgery from the hypoplasia of C1 or constraints due to C2 bone structure. In total, 108 screws were inserted into 23 patients using navigational assistance. The screws comprised 20 C1 lateral mass screws, 26 C2, 14 C3, or 4 C4 pedicle screws, 32 occipital screws, and 12 C1-C2 transarticular screws. There were no vascular or neural complications except for pedicle perforations that were detected in 2 (1.9%) patients and were corrected intraoperatively without any persistent nerves or vessel damage. The overall

Ball tip method for thoracic pedicle screw placement in patients with adolescent idiopathic scoliosis

International Nuclear Information System (INIS)

Watanabe, Kota; Matsumoto, Morio; Iizuka, Shingo

2008-01-01

The purpose of this study was to evaluate the efficacy of ball tip method for thoracic pedicle screw placements in idiopathic scoliosis patients. 24 patients with adolescent idiopathic scoliosis were included in this study. Conventional method was performed in 12 patients. Ball tip method was performed in 12 patients. Accuracy of the pedicle screw placement was evaluated based on the postoperative CT. In the ball tip method, a probe which was consisted of ball tip with flexible shaft was used. After removing of cortical bone at a starting point, the probe was inserted manually or sometimes with gently tapping by hammer. During the maneuver, the probe will gradually progress into cancellous bone in the pedicle, without perforating cortical bone in the pedicle. Following expansion of the hole by a rigid gear shift probe, screw was placed in the pedicle. 65.1% of screws were located within pedicle in the conventional group and 86.5% in the ball tip group. 5.3% of screws were located out of pedicle within 2 mm in the conventional group and 8.2% in the ball tip group. 15.8% of screws were located out of pedicle beyond 2 mm and 1.8% in the ball tip group. The ball tip method enhanced the accuracy of thoracic pedicle screw placements in adolescent idiopathic scoliosis patients. The ball tip method may be effective for accurate pedicle screw placement in patients with adolescent idiopathic scoliosis. (author)

Cervical Fusion for Absent Pedicle Syndrome Manifesting with Myelopathy.

Science.gov (United States)

Goodwin, C Rory; Desai, Atman; Khattab, Mohamed H; Elder, Benjamin D; Bydon, Ali; Wolinsky, Jean-Paul

2016-02-01

Absent congenital pedicle syndrome is a posterior arch defect characterized by numerous congenital and mechanical abnormalities that result from disconnection of the anterior and posterior columns of the spinal canal. Absent congenital pedicle syndrome is a rare anomaly that is most commonly diagnosed incidentally, after evaluation of minor trauma, or after complaints of chronic neck pain. We report a case of absent congenital pedicle syndrome in a patient who presented with myelopathy and lower extremity weakness and review the literature on the surgical management of this entity. A 32-year-old woman with a history of systemic lupus erythematosus presented to the Neurosurgery Service with progressive weakness in her upper and lower extremities, clonus, and hyperreflexia. Magnetic resonance imaging revealed congenital absence of the pedicles of C2, C3, C4, C5, and C6 with a congenitally narrow canal at C4-5. The patient underwent a staged anterior and posterior cervical decompression and fusion. She was placed in a halo after surgery; at the 1-year follow-up, she was ambulatory with demonstrated improvement in weakness and fusion of her cervical spine. Absent congenital pedicle syndrome is rare, and most reported cases were treated conservatively. Surgical management is reserved for patients with myelopathy or instability. Copyright © 2016 Elsevier Inc. All rights reserved.

Design and Evaluation of Shape-Changing Haptic Interfaces for Pedestrian Navigation Assistance.

Science.gov (United States)

Spiers, Adam J; Dollar, Aaron M

2017-01-01

Shape-changing interfaces are a category of device capable of altering their form in order to facilitate communication of information. In this work, we present a shape-changing device that has been designed for navigation assistance. 'The Animotus' (previously, 'The Haptic Sandwich' ), resembles a cube with an articulated upper half that is able to rotate and extend (translate) relative to the bottom half, which is fixed in the user's grasp. This rotation and extension, generally felt via the user's fingers, is used to represent heading and proximity to navigational targets. The device is intended to provide an alternative to screen or audio based interfaces for visually impaired, hearing impaired, deafblind, and sighted pedestrians. The motivation and design of the haptic device is presented, followed by the results of a navigation experiment that aimed to determine the role of each device DOF, in terms of facilitating guidance. An additional device, 'The Haptic Taco', which modulated its volume in response to target proximity (negating directional feedback), was also compared. Results indicate that while the heading (rotational) DOF benefited motion efficiency, the proximity (translational) DOF benefited velocity. Combination of the two DOF improved overall performance. The volumetric Taco performed comparably to the Animotus' extension DOF.

Pullout strength of misplaced pedicle screws in the thoracic and lumbar vertebrae - A cadaveric study

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Shyam K Saraf

2013-01-01

Full Text Available Background: The objective of this cadaveric study was to analyze the effects of iatrogenic pedicle perforations from screw misplacement on the mean pullout strength of lower thoracic and lumbar pedicle screws. We also investigated the effect of bone mineral density (BMD, diameter of pedicle screws, and the region of spine on the pullout strength of pedicle screws. Materials and Methods: Sixty fresh human cadaveric vertebrae (D10-L2 were harvested. Dual-energy X-ray absorptiometry (DEXA scan of vertebrae was done for BMD. Titanium pedicle screws of different diameters (5.2 and 6.2 mm were inserted in the thoracic and lumbar segments after dividing the specimens into three groups: a standard pedicle screw (no cortical perforation; b screw with medial cortical perforation; and c screw with lateral cortical perforation. Finally, pullout load of pedicle screws was recorded using INSTRON Universal Testing Machine. Results: Compared with standard placement, medially misplaced screws had 9.4% greater mean pullout strength and laterally misplaced screws had 47.3% lesser mean pullout strength. The pullout strength of the 6.2 mm pedicle screws was 33% greater than that of the 5.2 mm pedicle screws. The pullout load of pedicle screws in lumbar vertebra was 13.9% greater than that in the thoracic vertebra ( P = 0.105, but it was not statistically significant. There was no significant difference between pullout loads of vertebra with different BMD ( P = 0.901. Conclusion: The mean pullout strength was less with lateral misplaced pedicle screws while medial misplaced pedicle screw had more pullout strength. The pullout load of 6.2 mm screws was greater than that of 5.2 mm pedicle screws. No significant correlation was found between bone mineral densities and the pullout strength of vertebra. Similarly, the pullout load of screw placed in thoracic and lumbar vertebrae was not significantly different.

Extraction of user's navigation commands from upper body force interaction in walker assisted gait

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Pons José L

2010-08-01

Full Text Available Abstract Background The advances in technology make possible the incorporation of sensors and actuators in rollators, building safer robots and extending the use of walkers to a more diverse population. This paper presents a new method for the extraction of navigation related components from upper-body force interaction data in walker assisted gait. A filtering architecture is designed to cancel: (i the high-frequency noise caused by vibrations on the walker's structure due to irregularities on the terrain or walker's wheels and (ii the cadence related force components caused by user's trunk oscillations during gait. As a result, a third component related to user's navigation commands is distinguished. Results For the cancelation of high-frequency noise, a Benedict-Bordner g-h filter was designed presenting very low values for Kinematic Tracking Error ((2.035 ± 0.358·10-2 kgf and delay ((1.897 ± 0.3697·101ms. A Fourier Linear Combiner filtering architecture was implemented for the adaptive attenuation of about 80% of the cadence related components' energy from force data. This was done without compromising the information contained in the frequencies close to such notch filters. Conclusions The presented methodology offers an effective cancelation of the undesired components from force data, allowing the system to extract in real-time voluntary user's navigation commands. Based on this real-time identification of voluntary user's commands, a classical approach to the control architecture of the robotic walker is being developed, in order to obtain stable and safe user assisted locomotion.

Pedicle measurement of the thoracolumbar spine: a cadaveric, radiographic, and CT scan study in Filipinos

International Nuclear Information System (INIS)

Molano, A.M.V.; Sison, A.B.; Fong, H.C.; Lim, N.T.; Sabile, K.

1994-01-01

With the popular usage of spinal pedicular screw fixation, it is essential to have a knowledge of the morphometry of the pedicles of the spine of particular populations. This study compared the direct pedicle measurements of ten cadavers in an institution, with their respective radiographic and computerized tomographic (CT) scan values, and also compared the effective pedicle diameter (EPD) with the conventional outer pedicle diameter (OPD) measurements. A compilation of pedicle values was also made in X-ray and CT scan plates of a Filipino population. A statistical analysis made on the 2,760 pedicle measurements taken from cadaveric T6-L5 vertebrae showed that direct measurements were significantly different from X-ray and CT scan values. The mean values of the EPD differed from those of the OPD, but not statistically significant. Comparison with previous foreign studies revealed significant differences in these pedicle dimensions. Pedicle measurements in a living Filipino population were found to be significantly different statistically between sexes. Accurate measurement of the pedicle diameters and lengths are indeed critical for the success of a spinal stabilization procedure using pedicular screws. (author). 8 refs.; 5 figs.; 1 tab

Unilateral Pedicle Stress Fracture in a Long-Term Hemodialysis Patient with Isthmic Spondylolisthesis

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Keishi Maruo

2015-01-01

Full Text Available Most unilateral pedicle stress fractures occur on the contralateral side of patients with unilateral spondylolysis. However, there are few reports of unilateral pedicle stress fractures in patients with bilateral spondylolysis and spondylolisthesis. We report a unique case of unilateral pedicle stress fracture in a long-term hemodialysis patient with isthmic spondylolisthesis. A 65-year-old man who had undergone hemodialysis presented with lower back pain that had persisted for several years. The patient experienced severe right lower extremity pain with no history of trauma. Computed tomography revealed unilateral pedicle fracture with bilateral L5 spondylolysis and spondylolisthesis with progression of scoliosis. The patient underwent Gill laminectomy of L5 with pedicle screw fixation at L4-S1 and interbody fusion at L5-S1. The patient’s leg pain ceased immediately, and he began walking without leg pain. In our present patient, development of scoliosis caused by destructive spondyloarthropathy may have contributed to a unilateral pedicle fracture.

Nautical Navigation Aids (NAVAID) Locations

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Department of Homeland Security — Structures intended to assist a navigator to determine position or safe course, or to warn of dangers or obstructions to navigation. This dataset includes lights,...

Tapping insertional torque allows prediction for better pedicle screw fixation and optimal screw size selection.

Science.gov (United States)

Helgeson, Melvin D; Kang, Daniel G; Lehman, Ronald A; Dmitriev, Anton E; Luhmann, Scott J

2013-08-01

There is currently no reliable technique for intraoperative assessment of pedicle screw fixation strength and optimal screw size. Several studies have evaluated pedicle screw insertional torque (IT) and its direct correlation with pullout strength. However, there is limited clinical application with pedicle screw IT as it must be measured during screw placement and rarely causes the spine surgeon to change screw size. To date, no study has evaluated tapping IT, which precedes screw insertion, and its ability to predict pedicle screw pullout strength. The objective of this study was to investigate tapping IT and its ability to predict pedicle screw pullout strength and optimal screw size. In vitro human cadaveric biomechanical analysis. Twenty fresh-frozen human cadaveric thoracic vertebral levels were prepared and dual-energy radiographic absorptiometry scanned for bone mineral density (BMD). All specimens were osteoporotic with a mean BMD of 0.60 ± 0.07 g/cm(2). Five specimens (n=10) were used to perform a pilot study, as there were no previously established values for optimal tapping IT. Each pedicle during the pilot study was measured using a digital caliper as well as computed tomography measurements, and the optimal screw size was determined to be equal to or the first size smaller than the pedicle diameter. The optimal tap size was then selected as the tap diameter 1 mm smaller than the optimal screw size. During optimal tap size insertion, all peak tapping IT values were found to be between 2 in-lbs and 3 in-lbs. Therefore, the threshold tapping IT value for optimal pedicle screw and tap size was determined to be 2.5 in-lbs, and a comparison tapping IT value of 1.5 in-lbs was selected. Next, 15 test specimens (n=30) were measured with digital calipers, probed, tapped, and instrumented using a paired comparison between the two threshold tapping IT values (Group 1: 1.5 in-lbs; Group 2: 2.5 in-lbs), randomly assigned to the left or right pedicle on each

The application of data measurement before the pedicle vertebral arch fixed operation with spiral CT

International Nuclear Information System (INIS)

Yang Zenian; Luo Zhongyao; Chen Yong'an

2003-01-01

Objective: Authors carry out volume scans and 3D surface reconstruction. Then authors get the precise data of pedicle of vertebral arch, entering nail angle on horizontal direction, entering nail screw length, and the smallest horizontal diameter and entering nails' distance on pedicle of vertebral arch before the pedicle vertebral arch fixed operation. Method: Select the axial image of the widest pedicle of vertebral arch and it SSD image, measure the entering nail distance on the pedicle of vertebral arch, TSA, entering nail screw length, and the smallest horizontal diameter of the pedicle of vertebral arch. Result: The method helps to prepare the length, size and location of the nail and TSA for the pedicle of vertebral arch fixed operation, increase the operation success rate. Conclusion: This is a simple and reliable method to prepare the precise data of the nail length and size, TSA for the operation

Microwave ablation assisted by a real-time virtual navigation system for hepatocellular carcinoma undetectable by conventional ultrasonography

International Nuclear Information System (INIS)

Liu Fangyi; Yu Xiaoling; Liang Ping; Cheng Zhigang; Han Zhiyu; Dong Baowei; Zhang Xiaohong

2012-01-01

Objectives: To evaluate the efficiency and feasibility of microwave (MW) ablation assisted by a real-time virtual navigation system for hepatocellular carcinoma (HCC) undetectable by conventional ultrasonography. Methods: 18 patients with 18 HCC nodules (undetectable on conventional US but detectable by intravenous contrast-enhanced CT or MRI) were enrolled in this study. Before MW ablation, US images and MRI or CT images were synchronized using the internal markers at the best timing of the inspiration. Thereafter, MW ablation was performed under real-time virtual navigation system guidance. Therapeutic efficacy was assessed by the result of contrast-enhanced imagings after the treatment. Results: The target HCC nodules could be detected with fusion images in all patients. The time required for image fusion was 8–30 min (mean, 13.3 ± 5.7 min). 17 nodules were successfully ablated according to the contrast enhanced imagings 1 month after ablation. The technique effectiveness rate was 94.44% (17/18). The follow-up time was 3–12 months (median, 6 months) in our study. No severe complications occurred. No local recurrence was observed in any patients. Conclusions: MW ablation assisted by a real-time virtual navigation system is a feasible and efficient treatment of patients with HCC undetectable by conventional ultrasonography.

The biomechanical consequences of rod reduction on pedicle screws: should it be avoided?

Science.gov (United States)

Paik, Haines; Kang, Daniel G; Lehman, Ronald A; Gaume, Rachel E; Ambati, Divya V; Dmitriev, Anton E

2013-11-01

Rod contouring is frequently required to allow for appropriate alignment of pedicle screw-rod constructs. When residual mismatch is still present, a rod persuasion device is often used to achieve further rod reduction. Despite its popularity and widespread use, the biomechanical consequences of this technique have not been evaluated. To evaluate the biomechanical fixation strength of pedicle screws after attempted reduction of a rod-pedicle screw mismatch using a rod persuasion device. Fifteen 3-level, human cadaveric thoracic specimens were prepared and scanned for bone mineral density. Osteoporotic (n=6) and normal (n=9) specimens were instrumented with 5.0-mm-diameter pedicle screws; for each pair of comparison level tested, the bilateral screws were equal in length, and the screw length was determined by the thoracic level and size of the vertebra (35 to 45 mm). Titanium 5.5-mm rods were contoured and secured to the pedicle screws at the proximal and distal levels. For the middle segment, the rod on the right side was intentionally contoured to create a 5-mm residual gap between the inner bushing of the pedicle screw and the rod. A rod persuasion device was then used to engage the setscrew. The left side served as a control with perfect screw/rod alignment. After 30 minutes, constructs were disassembled and vertebrae individually potted. The implants were pulled in-line with the screw axis with peak pullout strength (POS) measured in Newton (N). For the proximal and distal segments, pedicle screws on the right side were taken out and reinserted through the same trajectory to simulate screw depth adjustment as an alternative to rod reduction. Pedicle screws reduced to the rod generated a 48% lower mean POS (495±379 N) relative to the controls (954±237 N) (p.05). In circumstances where a rod is not fully seated within the pedicle screw, the use of a rod persuasion device decreases the overall POS and work energy to failure of the screw or results in outright

L5 pedicle length is increased in subjects with spondylolysis: an anatomic study of 1072 cadavers.

Science.gov (United States)

Bajwa, Navkirat S; Toy, Jason O; Ahn, Nicholas U

2012-11-01

In spondylolisthesis, it is believed that as L5 slips on S1, the pedicle may become elongated in response to the instability in an attempt to bridge the defect. Whether patients with spondylolysis, which is largely developmental, also develop elongation of the pedicles is unknown. The purpose of this study is to evaluate and quantify the increase in L5 pedicle length in subjects with spondylolysis as compared with normal healthy subjects. Nine hundred fifty-two human cadaveric specimens without spondylolysis and 120 specimens with spondylolysis from the Hamann-Todd Osteological Collection were examined by a single examiner. Baseline data, including age, sex, and race of specimens, were collected. Digital calipers were used to measure the pedicle lengths at the L5 level. Linear regression analysis was performed to compare the L5 pedicle lengths in healthy patients and patients with spondylolysis. Linear regression showed a significant association of increased L5 pedicle length in subjects with spondylolysis. The average L5 pedicle length in subjects with spondylolysis was greater compared with subjects without spondylolysis. In spondylolytic specimens, pedicles start to elongate after the age of 40 years. The pedicle lengths increase progressively from 5.6 mm at 40 years to 6.7 mm at 80 years with a 1% to 3% increment every decade. The pedicle lengths showed little variation in specimens from healthy subjects. In spondylolytic specimens, there is progressive elongation of L5 pedicle length after the third decade. An increase in L5 pedicle length in all age groups compared with the specimens from healthy subjects suggests that pathologic changes occur in bony anatomy of L5 vertebrae as early as adolescence when the condition develops.

Pedicle marrow signal intensity changes in the lumbar spine: a manifestation of facet degenerative joint disease

International Nuclear Information System (INIS)

Morrison, J.L.; Kaplan, P.A.; Dussault, R.G.; Anderson, M.W.

2000-01-01

Objective. Signal intensity changes in lumbar pedicles, similar to those described in vertebral body endplates adjacent to degenerated discs, have been described as an ancillary sign of spondylolysis on MRI. The purpose of this study was to determine whether pedicle marrow signal intensity changes also occur in association with facet degenerative joint disease.Design. Eighty-nine lumbar spine MRI examinations without spondylolysis were reviewed for marrow signal intensity changes in pedicles and vertebral bodies as well as for facet degenerative joint disease.Results. Five percent (46/890) of lumbar pedicles in 23 patients had marrow signal intensity changes. Ninety-one percent (42/46) of the abnormal pedicles had adjacent degenerative joint disease of the facets, while only 21% (189/890) of normal pedicles had adjacent facet degenerative joint disease (p<0.001). Eighty-nine percent (41/46) of the pedicles with marrow signal intensity changes had adjacent degenerative disc disease.Conclusions. Pedicle marrow signal intensity changes are not a specific sign of spondylolysis; they are commonly seen with adjacent facet degenerative joint disease in the absence of spondylolysis. Pedicle marrow signal intensity changes are probably a response to abnormal stresses related to abnormal motion or loading caused by the degenerative changes in the spinal segment. (orig.)

Pedicle marrow signal intensity changes in the lumbar spine: a manifestation of facet degenerative joint disease

Energy Technology Data Exchange (ETDEWEB)

Morrison, J.L.; Kaplan, P.A.; Dussault, R.G.; Anderson, M.W. [Dept. of Radiology, Univ. of Virginia Health System, Charlottesville, VA (United States)

2000-12-01

Objective. Signal intensity changes in lumbar pedicles, similar to those described in vertebral body endplates adjacent to degenerated discs, have been described as an ancillary sign of spondylolysis on MRI. The purpose of this study was to determine whether pedicle marrow signal intensity changes also occur in association with facet degenerative joint disease.Design. Eighty-nine lumbar spine MRI examinations without spondylolysis were reviewed for marrow signal intensity changes in pedicles and vertebral bodies as well as for facet degenerative joint disease.Results. Five percent (46/890) of lumbar pedicles in 23 patients had marrow signal intensity changes. Ninety-one percent (42/46) of the abnormal pedicles had adjacent degenerative joint disease of the facets, while only 21% (189/890) of normal pedicles had adjacent facet degenerative joint disease (p<0.001). Eighty-nine percent (41/46) of the pedicles with marrow signal intensity changes had adjacent degenerative disc disease.Conclusions. Pedicle marrow signal intensity changes are not a specific sign of spondylolysis; they are commonly seen with adjacent facet degenerative joint disease in the absence of spondylolysis. Pedicle marrow signal intensity changes are probably a response to abnormal stresses related to abnormal motion or loading caused by the degenerative changes in the spinal segment. (orig.)

Comparison of measurement results between cervical pedicle specimens and CT images

International Nuclear Information System (INIS)

Zhang Guangjian; Li Hua; Liu Haiyan; Gao Zhenping

2011-01-01

Objective: To compare the difference between the measurement results of the cervical pedicle specimens and CT image, and provide the basis for clinical cervical screw internal fixation operation. Methods: Twenty-seven Chinese adult cadaver cervical specimens including C3 to C7 vertebrae were measured by a digital calipers and CT image, containing pedicle height (PH, PH'), pedicle width(PW, PW'), total pedicle length (TL, TL') and two pedicle lengths(PL1, PL2; PL1', PL2'). The results of specimens and CT image were compared. Results: Different cervical vertebra in the same side of specimens or CT images, PW (PW'): C3, C4< C5, C6 (P<0.05), C5, C6< C7 (P<0.01); PH (PH'): there were no significant differences; TL, PL1, PL2 (TL', PL1', PL2'): there were no marked differences. In the same cervical vertebra of the specimens or CT images, PW (PW')< PH (PH') (P<0.01), PL1 (PL1') < PL2 (PL2') (P<0.01). Conclusion: The results of measurement by CT images are not markedly different from that of specimens. CT image measurement is available before cervical screw internal fixation operation. (authors)

Satellite Imagery Assisted Road-Based Visual Navigation System

Science.gov (United States)

Volkova, A.; Gibbens, P. W.

2016-06-01

There is a growing demand for unmanned aerial systems as autonomous surveillance, exploration and remote sensing solutions. Among the key concerns for robust operation of these systems is the need to reliably navigate the environment without reliance on global navigation satellite system (GNSS). This is of particular concern in Defence circles, but is also a major safety issue for commercial operations. In these circumstances, the aircraft needs to navigate relying only on information from on-board passive sensors such as digital cameras. An autonomous feature-based visual system presented in this work offers a novel integral approach to the modelling and registration of visual features that responds to the specific needs of the navigation system. It detects visual features from Google Earth* build a feature database. The same algorithm then detects features in an on-board cameras video stream. On one level this serves to localise the vehicle relative to the environment using Simultaneous Localisation and Mapping (SLAM). On a second level it correlates them with the database to localise the vehicle with respect to the inertial frame. The performance of the presented visual navigation system was compared using the satellite imagery from different years. Based on comparison results, an analysis of the effects of seasonal, structural and qualitative changes of the imagery source on the performance of the navigation algorithm is presented. * The algorithm is independent of the source of satellite imagery and another provider can be used

Pedicle distraction increases intervertebral and spinal canal area in a cadaver and bone model

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Hughes Matthew

2018-01-01

Discussion: For each increase in pedicle distraction the area of the spinal and vertebral foramen increases. Pedicle distraction could potentially be used to alleviate spinal stenosis and root impingement. A potential osteotomy plane could be at the midpoint of the pedicle with minimal risk to nerve roots and soft tissue restrictions to prevent distraction.

OUTCOMES OF HILAR PEDICLE CONTROL USING SUTURE LIGATION DURING LAPAROSCOPIC SPLENECTOMY.

Science.gov (United States)

Makgoka, M

2017-06-01

Laparoscopic splenectomy is a well described gold standard procedure for various indications. One of the key steps during laparoscopic splenectomy is the hilar pedicle vessels control, which can be challenging in most cases. Most centres around the world recommend the use Ligaclib or endovascular staplers as Methods of choice for hilar pedicle control but the issue is the cost and efficiency of the laparoscopic haemostatic devices. A descriptive retrospective study of patients who had laparoscopic splenectomy from 2013 to present. Hilar splenic vessel control was done with suture ligation. We looked at outcomes of patients offered this technique, complications of this technique, and describing the technique of hilar control in laparoscopic splenectomy. Total of 27 patients had laparoscopic splenectomy with splenic hilar pedicle control with suture ligation. Mean operative time, mean blood volume loss, length of hospital stay, postoperative complications conversion to laparotomy. Laparoscopic hilar pedicle control with suture ligation is safe and effective for the patient in our hospital setting.

PEDICLE TONGUE FLAP SURGERY IN ORAL SUBMUCOUS FIBROSIS

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Muthubabu K

2016-09-01

Full Text Available BACKGROUND Oral submucous fibrosis is a disease of unknown aetiology and is a legacy of Indians. It has been variously treated both medically and surgically but neither has been found to be rewarding. Various groups have been studying the therapy schedules and aetiological association, but the conclusions have remained unclear. AIM The study aims to focus on newer surgical therapy stressing on the mechanics and use of pedicle tongue flap in the management of this condition. METHODS AND MATERIALS The study comprised of 40 patients from our outpatient department suffering from oral submucous fibrosis in the age group of 11 to 70 years. The contributory factors of oral submucous fibrosis and the symptoms of the disease were evaluated and the role of pedicle tongue flap surgery in the management of this disease which is a premalignant condition is discussed. RESULTS AND CONCLUSION Pedicle tongue flap surgery has given promising results in the treatment of trismus due to oral submucous fibrosis. After the surgery, none of our patients developed any malignant change.

Positioning of pedicle screws in adolescent idiopathic scoliosis using electromyography

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Bruno Moreira Gavassi

2015-06-01

Full Text Available OBJECTIVE: To analyze the occurrence of poor positioning of pedicle screws inserted with the aid of intraoperative electromyographic stimulation in the treatment of Adolescent Idiopathic Scoliosis (AIS.METHODS: This is a prospective observational study including all patients undergoing surgical treatment for AIS, between March and December 2013 at a single institution. All procedures were monitored by electromyography of the inserted pedicle screws. The position of the screws was evaluated by assessment of postoperative CT and classified according to the specific AIS classification system.RESULTS: Sixteen patients were included in the study, totalizing 281 instrumented pedicles (17.5 per patient. No patient had any neurological deficit or complaint after surgery. In the axial plane, 195 screws were found in ideal position (69.4% while in the sagittal plane, 226 screws were found in ideal position (80.4%. Considering both the axial and the sagittal planes, it was observed that 59.1% (166/281 of the screws did not violate any cortical wall.CONCLUSION: The use of pedicle screws proved to be a safe technique without causing neurological damage in AIS surgeries, even with the occurrence of poor positioning of some implants.

DEEP-SEE: Joint Object Detection, Tracking and Recognition with Application to Visually Impaired Navigational Assistance

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Ruxandra Tapu

2017-10-01

Full Text Available In this paper, we introduce the so-called DEEP-SEE framework that jointly exploits computer vision algorithms and deep convolutional neural networks (CNNs to detect, track and recognize in real time objects encountered during navigation in the outdoor environment. A first feature concerns an object detection technique designed to localize both static and dynamic objects without any a priori knowledge about their position, type or shape. The methodological core of the proposed approach relies on a novel object tracking method based on two convolutional neural networks trained offline. The key principle consists of alternating between tracking using motion information and predicting the object location in time based on visual similarity. The validation of the tracking technique is performed on standard benchmark VOT datasets, and shows that the proposed approach returns state-of-the-art results while minimizing the computational complexity. Then, the DEEP-SEE framework is integrated into a novel assistive device, designed to improve cognition of VI people and to increase their safety when navigating in crowded urban scenes. The validation of our assistive device is performed on a video dataset with 30 elements acquired with the help of VI users. The proposed system shows high accuracy (>90% and robustness (>90% scores regardless on the scene dynamics.

Bilateral human-robot control for semi-autonomous UAV navigation

NARCIS (Netherlands)

Wopereis, Han Willem; Fumagalli, Matteo; Stramigioli, Stefano; Carloni, Raffaella

2015-01-01

This paper proposes a semi-autonomous bilateral control architecture for unmanned aerial vehicles. During autonomous navigation, a human operator is allowed to assist the autonomous controller of the vehicle by actively changing its navigation parameters to assist it in critical situations, such as

Pull out Strength of Dual Outer Diameter Pedicle Screws Compared to Uncemented and Cemented Standard Pedicle Screws: A Biomechanical in vitro Study.

Science.gov (United States)

Lorenz, Andrea; Leichtle, Carmen I; Frantz, Sandra; Bumann, Marte; Tsiflikas, Ilias; Shiozawa, Thomas; Leichtle, Ulf G

2017-05-01

To analyze the potential of the dual outer diameter screw and systematically evaluate the pull-out force of the dual outer diameter screw compared to the uncemented and cemented standard pedicle screws with special regard to the pedicle diameter and the vertebra level. Sixty vertebrae of five human spines (T 6 -L 5 ) were sorted into three study groups for pairwise comparison of the uncemented dual outer diameter screw, the uncemented standard screw, and the cemented standard screw, and randomized with respect to bone mineral density (BMD) and vertebra level. The vertebrae were instrumented, insertion torque was determined, and pull-out testing was performed using a material testing machine. Failure load was evaluated in pairwise comparison within each study group. The screw-to-pedicle diameter ratio was determined and the uncemented dual outer diameter and standard screws were compared for different ratios as well as vertebra levels. Significantly increased pull-out forces were measured for the cemented standard screw compared to the uncemented standard screw (+689 N, P dual outer diameter screw (+403 N, P dual outer diameter screw to the uncemented standard screw in the total study group, a distinct but not significant increase was measured (+149 N, P = 0.114). Further analysis of these two screws, however, revealed a significant increase of pull-out force for the dual outer diameter screw in the lumbar region (+247 N, P = 0.040), as well as for a screw-to-pedicle diameter ratio between 0.6 and 1 (+ 488 N, P = 0.028). For clinical application, cement augmentation remains the gold standard for increasing screw stability. According to our results, the use of a dual outer diameter screw is an interesting option to increase screw stability in the lumbar region without cement augmentation. For the thoracic region, however, the screw-to-pedicle diameter should be checked and attention should be paid to screw cut out, if the dual outer diameter screw is considered. �

A novel route for placing free flap pedicle from a palatal defect

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Rajeev B Ahuja

2014-01-01

Full Text Available One of the better options available to repair a large palatal defect is by employing a free flap. Almost all the times such free flaps are plumbed to facial vessels. The greatest challenge in such cases is the placement of the pedicle from palatal shelf to recipient vessels because there is no direct route available. As majority of large palatal fistulae are encountered in operated cleft palates there is a possibility of routing the pedicle through a cleft in the maxillary arch or via pyriform aperture. When such a possibility doesn′t exist the pedicle is routed behind the maxillary arch. We describe a novel technique of pedicle placement through a maxillary antrostomy, in this case report, where a large palatal fistula in a 16 year old boy was repaired employing a free radial artery forearm flap. The direct route provided by maxillary antrostomy is considered the most expeditious of all possibilities mentioned above.

Morphology of the atlas pedicle revisited: a morphometric CT-based study on 120 patients.

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Qian, Li-Xiong; Hao, Ding-Jun; He, Bao-Rong; Jiang, Yong-Hong

2013-05-01

To quantify the dimensions of the atlas pedicles and to analyze the relationship between extra medullary height (EMH) with intra medullary height (IMH) of the atlas pedicle. The images of the patients who had CT scanning and three-dimensional (3D) reconstruction involving atlantoaxial complex between June 2011 and April 2012 and meet our inclusion criteria were studied retrospectively. After reformatting the original images, the EMH and IMH of the atlas pedicles were measured. Extra medullary height and IMH were, respectively, 4.83 ± 1.13 and 1.29 ± 1.10 mm for males and 3.75 ± 0.93 and 0.60 ± 0.83 mm for females, with statistical difference (P atlas pedicles were measured by using CT images of the atlas, providing anatomic parameters for surgery. They showed a certain correlation but with a high variability. C1 pedicle screw fixation was well performed when the medullary canal was ≥1 mm, but the surgical procedure should be careful when it was between 0 and 1 mm, and avoided when there was no medullary canal in the atlas pedicle! So 3D CT reconstruction should be conducted to obtain data and establish individualized fixation strategy preoperatively.

A multi-level rapid prototyping drill guide template reduces the perforation risk of pedicle screw placement in the lumbar and sacral spine.

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Merc, Matjaz; Drstvensek, Igor; Vogrin, Matjaz; Brajlih, Tomaz; Recnik, Gregor

2013-07-01

The method of free-hand pedicle screw placement is generally safe although it carries potential risks. For this reason, several highly accurate computer-assisted systems were developed and are currently on the market. However, these devices have certain disadvantages. We have developed a method of pedicle screw placement in the lumbar and sacral region using a multi-level drill guide template, created with the rapid prototyping technology and have validated it in a clinical study. The aim of the study was to manufacture and evaluate the accuracy of a multi-level drill guide template for lumbar and first sacral pedicle screw placement and to compare it with the free-hand technique under fluoroscopy supervision. In 2011 and 2012, a randomized clinical trial was performed on 20 patients. 54 screws were implanted in the trial group using templates and 54 in the control group using the fluoroscopy-supervised free-hand technique. Furthermore, applicability for the first sacral level was tested. Preoperative CT-scans were taken and templates were designed using the selective laser sintering method. Postoperative evaluation and statistical analysis of pedicle violation, displacement, screw length and deviation were performed for both groups. The incidence of cortex perforation was significantly reduced in the template group; likewise, the deviation and displacement level of screws in the sagittal plane. In both groups there was no significantly important difference in deviation and displacement level in the transversal plane as not in pedicle screw length. The results for the first sacral level resembled the main investigated group. The method significantly lowers the incidence of cortex perforation and is therefore potentially applicable in clinical practice, especially in some selected cases. The applied method, however, carries a potential for errors during manufacturing and practical usage and therefore still requires further improvements.

[Polymethylmethacrylate augmentation of bone cement-injectable cannulated pedicle screws for the treatment of degenerative lumbar diseases with osteoporosis].

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Sun, H L; Li, C D; Yang, Z C; Yi, X D; Liu, H; Lu, H L; Li, H; Wang, Y

2016-12-18

To describe the application of polymethylmethacrylate augmentation of bone cement-injectable cannulated pedicle screws for the treatment of degenerative lumbar diseases with osteoporosis. Observation group included 14 cases of degenerative lumbar diseases with osteoporosis received polymethylmethacrylate augmentation of bone cement-injectable cannulated pedicle screws from November 2014 to July 2015, control group included 12 cases of degenerative lumbar diseases with osteoporosis received polymethylmethacrylate augmentation with traditional pedicle screws.The operation time, blood loss, number of pedicle screws and number of augmented pedicle screws in the two groups were compared. The bone cement leakage and pulmonary bone cement embolism in the two groups were also compared. The fusion rate and pedicle screws loosening by lumbar X ray and dynamic X ray were evaluated. The clinical results were assessed by visual analog scale (VAS) of pain on lumbar and lower limbers, lumbar Japanese Orthopaedic Association scores (JOA), Prolo functional scores and Oswestry disability (ODI) scores. Differences of operation time and blood loss in the two groups were not statistically significant. The average number of pedicle screws was 9.9±4.7 and the average number of augmented pedicle screws was 5.9±2.6 in observation group while the average number of pedicle screws was 7.1±2.8 and the average number of augmented pedicle screws was 3.0±1.9 in control group. The ratio of augmented pedicle screws was higher in observation group than in control group (0.69±0.30 vs.0.47±0.30,Pdegenerative lumbar diseases with osteoporosis was effective, with simple working processes and lower risk of bone cement leakage. The short-term clinical result was good.

Clinical and radiological results 6 years after treatment of traumatic thoracolumbar burst fractures with pedicle screw instrumentation and balloon assisted endplate reduction

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Verlaan, Jorrit Jan; Somers, Inne; Dhert, Wouter J A; Oner, F. Cumhur

2015-01-01

Background context  When used to fixate traumatic thoracolumbar burst fractures, pedicle screw constructs may fail in the presence of severe vertebral body comminution as the intervertebral disc can creep through the fractured endplates leading to insufficient anterior column support.

Long-term follow-up and patient satisfaction after reduction mammoplasty: Superomedial versus inferior pedicle

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Mohamed Makboul

2016-01-01

Full Text Available Background: Surgery for hypertrophied breasts represents a challenge for plastic surgeons. The search for a good post-surgical cosmetic breast has led to the development of many techniques. Objectives for reduction mammoplasty are to achieve elevated, symmetrical breasts, a round shape, good projection, small cicatrices that are not very perceptible, and a lasting result. Patients and Methods: This study was carried out on sixty cases who had done reduction mammoplasty from January 2009 to December 2014. All patients were examined and were asked for late post-operative results and overall patients' satisfaction. Results: Long-term projection and contour of the breast were more satisfactory among patients who had superomedial pedicle with a statistically significant difference. No statistically significant difference was observed between patients underwent either superomedial or inferior pedicle reduction mammoplasty with regard to breast shape symmetry, nipple symmetry and sensation. The mean score for satisfaction was higher among patients who underwent superomedial pedicle rather than the inferior pedicle method. Conclusion: The superomedial pedicle shows better long-term cosmetic results.

Pedicle distraction increases intervertebral and spinal canal area in a cadaver and bone model.

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Hughes, Matthew; Papadakos, Nikolaos; Bishop, Tim; Bernard, Jason

2018-01-01

Lumbar spinal stenosis is degenerative narrowing of the spinal canal and/or intervertebral foramen causing compression of the spinal cord and nerve roots. Traditional decompression techniques can often cause significant trauma and vertebral instability. This paper evaluates a method of increasing pedicle length to decompress the spinal and intervertebral foramen, which could be done minimally invasive. Three Sawbone (Sawbones Europe, Sweden) and 1 cadaveric lumbar spine underwent bilateral pedicle distraction at L4. A pedicle channel was drilled between the superior articular process and transverse process into the vertebral body. The pedicles underwent osteotomy at the midpoint. Screws were inserted bilaterally and fixated distraction of 0 mm, 2 mm, 4 mm and 6 mm. CT images were taken at each level of distraction. Foramen area was measured in the sagittal plane at L3/4. Spinal canal area was measured at L4 in the axial images. The cadaver was used to evaluate safety of osteotomy and soft tissue interactions preventing distraction. Statistical analysis was by student paired t-test and Pearson rank test. Increasing distraction led to greater Spinal canal area. From 4.27 cm 2 to 5.72 cm 2 (p = 0.002) with 6 mm distraction. A Maximal increase of 34.1%. Vertebral foramen area also increased with increasing pedicle distraction. From 2.43 cm 2 to 3.22 cm 2 (p = 0.022) with 6 mm distraction. A maximal increase of 32.3%. The cadaver spinal canal increased in area by 21.7%. The vertebral foramen increased in area by 36.2% (left) and 22.6% (right). For each increase in pedicle distraction the area of the spinal and vertebral foramen increases. Pedicle distraction could potentially be used to alleviate spinal stenosis and root impingement. A potential osteotomy plane could be at the midpoint of the pedicle with minimal risk to nerve roots and soft tissue restrictions to prevent distraction. © The Authors, published by EDP Sciences, 2018.

[Efficacy of Sacroiliac Joint Anterior Approach with Double Reconstruction Plate and Computer Assisted Navigation Percutaneous Sacroiliac Screw for Treating Tile C1 Pelvic Fractures].

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Tan, Zhen; Fang, Yue; Zhang, Hui; Liu, Lei; Xiang, Zhou; Zhong, Gang; Huang, Fu-Guo; Wang, Guang-Lin

2017-09-01

To compare the efficacy of sacroiliac joint anterior approach with double reconstruction plate and computer assisted navigation percutaneous sacroiliac screw for treating Tile C1 pelvic fractures. Fifty patients with pelvic Tile C1 fractures were randomly divided into two groups ( n =25 for each) in the orthopedic department of West China Hospital of Sichuan University from December 2012 to November 2014. Patients in group A were treated by sacroiliac joint dislocation with anterior plate fixation. Patients in group B were treated with computerized navigation for percutaneous sacroiliac screw. The operation duration,intraoperative blood loss,incision length,and postoperative complications (nausea,vomiting,pulmonary infection,wound complications,etc.) were compared between the two groups. The postoperative fracture healing time,postoperative patient satisfaction,and postoperative fractures MATTA scores (to evaluate fracture reduction),postoperative MAJEED function scores,and SF36 scores of the patients were also recorded and compared. No significant differences in baseline characteristics were found between the two groups of patients. All of the patients in both groups had their operations successfully completed. Patients in group B had significantly shorter operations and lower intraoperative blood loss,incision length and postoperative complications than those in group A ( P 0.05). Sacroiliac joint anterior approach with double reconstruction plate and computer assisted navigation percutaneous sacroiliac screws are both effective for treating Tile C1type pelvic fractures,with similar longterm efficacies. However,computer assisted navigation percutaneous sacroiliac screw has the advantages of less trauma,less bleeding,and quicker.

Diaphragmatic hernia repair using a rectus abdominis muscle pedicle flap in three dogs.

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Chantawong, P; Komin, K; Banlunara, W; Kalpravidh, M

2013-01-01

To report the clinical use of a pedicle flap from the rectus abdominis muscle to repair extensive diaphragmatic tears in dogs with diaphragmatic hernia. Three dogs with a combination of radial and circumferential diaphragmatic tears were studied. The circumferential tear was repaired by suturing the wound edge with the edge at the abdominal wall. A pedicle flap of the rectus abdominis muscle was used for repairing the radial tear. The dogs were examined radiographically for lung and diaphragm appearance and evidence of reherniation at 10 days, and at one, two, and four months after surgery, and fluoroscopically for paradoxical motion of the diaphragm at one and four months. The rectus abdominis muscle pedicle flap was successfully used in all three dogs. The animals recovered uneventfully without evidence of reherniation during the four follow-up months. Fluoroscopic examination revealed no paradoxical motion of the diaphragm. A rectus abdominis muscle pedicle flap can be used for repairing large diaphragmatic defects in dogs.

A new system of computer-assisted navigation leading to reduction in operating time in uncemented total hip replacement in a matched population.

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Chaudhry, Fouad A; Ismail, Sanaa Z; Davis, Edward T

2018-05-01

Computer-assisted navigation techniques are used to optimise component placement and alignment in total hip replacement. It has developed in the last 10 years but despite its advantages only 0.3% of all total hip replacements in England and Wales are done using computer navigation. One of the reasons for this is that computer-assisted technology increases operative time. A new method of pelvic registration has been developed without the need to register the anterior pelvic plane (BrainLab hip 6.0) which has shown to improve the accuracy of THR. The purpose of this study was to find out if the new method reduces the operating time. This was a retrospective analysis of comparing operating time in computer navigated primary uncemented total hip replacement using two methods of registration. Group 1 included 128 cases that were performed using BrainLab versions 2.1-5.1. This version relied on the acquisition of the anterior pelvic plane for registration. Group 2 included 128 cases that were performed using the newest navigation software, BrainLab hip 6.0 (registration possible with the patient in the lateral decubitus position). The operating time was 65.79 (40-98) minutes using the old method of registration and was 50.87 (33-74) minutes using the new method of registration. This difference was statistically significant. The body mass index (BMI) was comparable in both groups. The study supports the use of new method of registration in improving the operating time in computer navigated primary uncemented total hip replacements.

Navigation-synchronized multimodal control wheelchair from brain to alternative assistive technologies for persons with severe disabilities.

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Puanhvuan, Dilok; Khemmachotikun, Sarawin; Wechakarn, Pongsakorn; Wijarn, Boonyanuch; Wongsawat, Yodchanan

2017-04-01

Currently, electric wheelchairs are commonly used to improve mobility in disabled people. In severe cases, the user is unable to control the wheelchair by themselves because his/her motor functions are disabled. To restore mobility function, a brain-controlled wheelchair (BCW) would be a promising system that would allow the patient to control the wheelchair by their thoughts. P300 is a reliable brain electrical signal, a component of visual event-related potentials (ERPs), that could be used for interpreting user commands. This research aimed to propose a prototype BCW to allowed severe motor disabled patients to practically control a wheelchair for use in their home environment. The users were able to select from 9 possible destination commands in the automatic mode and from 4 directional commands (forward, backward, turn left and right) in the shared-control mode. These commands were selected via the designed P300 processing system. The wheelchair was steered to the desired location by the implemented navigation system. Safety of the user was ensured during wheelchair navigation due to the included obstacle detection and avoidance features. A combination of P300 and EOG was used as a hybrid BCW system. The user could fully operate the system such as enabling P300 detection system, mode shifting and stop/cancelation command by performing a different consecutive blinks to generate eye blinking patterns. The results revealed that the prototype BCW could be operated in either of the proposed modes. With the new design of the LED-based P300 stimulator, the average accuracies of the P300 detection algorithm in the shared-control and automatic modes were 95.31 and 83.42% with 3.09 and 3.79 bits/min, respectively. The P300 classification error was acceptable, as the user could cancel an incorrect command by blinking 2 times. Moreover, the proposed navigation system had a flexible design that could be interfaced with other assistive technologies. This research developed

EFFECT OF PILOT HOLE TAPPING ON PULLOUT STRENGTH AND INSERTION TORQUE OF DUAL CORE PEDICLE SCREWS.

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Rosa, Rodrigo César; Silva, Patrícia; Falcai, Maurício José; Shimano, Antônio Carlos; Defino, Helton Luiz Aparecido

2010-01-01

To evaluate the influence of pilot hole tapping on pullout resistance and insertion torque of pedicle screws with a conical core. Mechanical tests using a universal testing machine were performed on pedicle screws with a conical core that were inserted into pedicles in the fifth lumbar vertebra of calves. The insertion torque was measured using a torque meter with a capacity of 10 Nm, which was considered to be the highest torque value. The pilot holes were prepared using a probe of external diameter 3.8 mm and tapping of the same dimensions and thread characteristics as the screw. Decreased insertion torque and pullout resistance were observed in the group with prior tapping of the pilot hole. Pilot hole tapping reduced the insertion torque and pullout resistance of pedicle screws with a conical core that had been inserted into the pedicle of the fifth lumbar vertebra of calves.

Occam paradox? A variation of tapia syndrome and an unreported complication of guidewire-assisted pedicle screw insertion.

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Emohare, Osa; Peterson, Erik; Slinkard, Nathaniel; Janus, Seth; Morgan, Robert

2013-10-01

Study Design Case report. Clinical Question The clinical aim is to report on a previously unknown association between guidewire-assisted pedicle screw insertion and neuropraxia of the recurrent laryngeal nerve (RLN), and how this may overlap with the signs of Tapia syndrome; we also report our approach to the clinical management of this patient. Methods A 17-year-old male patient with idiopathic scoliosis experienced Tapia syndrome after posterior instrumentation and arthrodesis at the level of T1-L1. After extubation, the patient had a hoarse voice and difficulty in swallowing. Imaging showed a breach in the cortex of the anterior body of T1 corresponding to the RLN on the right. Results Otolaryngological examination noted right vocal fold immobility, decreased sensation of the endolarynx, and pooling of secretions on flexible laryngoscopy that indicated right-sided cranial nerve X injury and left-sided tongue deviation. Aspiration during a modified barium swallow prompted insertion of a percutaneous endoscopic gastrostomy tube before the patient was sent home. On postoperative day 20, a barium swallow demonstrated reduced aspiration, and the patient reported complete resolution of symptoms. The feeding tube was removed, and the patient resumed a normal diet 1 month later. Tapia syndrome, or persistent unilateral laryngeal and hypoglossal paralysis, is an uncommon neuropraxia, which has previously not been observed in association with a breached vertebral body at T1 along the course of the RLN. Conclusion Tapia syndrome should be a differential diagnostic consideration whenever these symptoms persist postoperatively and spine surgeons should be aware of this as a potential complication of guidewires in spinal instrumentation.

Subarachnoid and basal cistern navigation through the sacral hiatus with guide wire assistance.

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Layer, Lauren; Riascos, Roy; Firouzbakht, Farhood; Amole, Adewumi; Von Ritschl, Rudiger; Dipatre, Pier; Cuellar, Hugo

2011-07-01

Intraspinal navigation with catheters and fiberscopes has shown feasible results for diagnosis and treatment of intraspinal and intracranial lesions. The most common approach, lumbar puncture, has allowed access to the spinal cord, however, coming with the difficulties of fiberscope damage and decreased torque for guidance. Our objective in this study is to allow an alternate access, the sacral hiatus, with guide wire assistance into the subarachnoid and intracranial structures, while easing the angle of entry and increasing torque. We advanced catheters with guide wire and fluoroscopy assistance into the sacral hiatus of three cadavers. After entry, the thecal sac was punctured and the catheter with guide wire was advanced rostrally until positioned in the basal cisterns of the brain. We confirmed catheter placement with contrast injection, autopsy, and dissection. In our study, the sacral hiatus was easily accessed, but resistance was found when attempting to puncture the thecal sac. The advancement of the catheter with guide wire assistance glided easily rostrally until some mild resistance was discovered at entry into the foramen magnum. With redirection, all catheters passed with ease into the basal cisterns. Positioning was confirmed with contrast injection with fluoroscopy evidence, autopsy, and dissection. There was no macroscopic or microscopic evidence of damage to the spinal roots, spinal cord, or cranial nerves. The sacral hiatus with guide wire assistance is an accessible conduit for uncomplicated entry into the subarachnoid and basal cistern space without damaging surrounding structures.

Descending aortic injury by a thoracic pedicle screw during posterior reconstructive surgery: a case report.

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Watanabe, Kei; Yamazaki, Akiyoshi; Hirano, Toru; Izumi, Tomohiro; Sano, Atsuki; Morita, Osamu; Kikuchi, Ren; Ito, Takui

2010-09-15

Case report. To describe an iatrogenic aortic injury by pedicle screw instrumentation during posterior reconstructive surgery of spinal deformity. Iatrogenic major vascular injuries during anterior instrumentation procedures have been reported by several authors, but there have been few reports regarding iatrogenic major vascular injuries during posterior instrumentation procedures. A 57-year-old woman with thoracolumbar kyphosis due to osteoporotic T12 vertebral fracture underwent posterior correction and fusion (T10-L2), using segmental pedicle screw construct concomitant with T12 pedicle subtraction osteotomy. Postoperative routine plain radiographs and computed tomography myelography demonstrated a misplaced left T10 pedicle screw, which was in contact with the posteromedial aspect of the thoracic aorta, and suspected penetration of the aortic wall. The patient underwent removal of the pedicle screw, and repair of the penetrated aortic wall through a simultaneous anterior-posterior approach. The patient tolerated the procedure well without neurologic sequelae, and was discharged several days after removal of a left tube thoracostomy. Plain radiographs demonstrated solid fusion at the osteotomy site and no loosening of hardware. Preoperative neurologic symptoms improved completely at 18-months follow-up. Use of pedicle screw instrumentation has the potential to cause major vascular injury during posterior spinal surgery, and measures to prevent this complication must be taken. Timely diagnosis and treatment are essential to prevent both early and delayed complications and death.

Internal fixation and muscle pedicle bone grafting in femoral neck fractures

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Gupta A

2008-01-01

Full Text Available Background: The treatment of displaced intracapsular femoral neck fracture is still an unsolved problem. Non-union and avascular necrosis are the two main complications of this fracture, especially if patient presents late. Muscle pedicle bone grafting has been advocated to provide additional blood supply. We present analysis of our 32 cases of displaced femoral neck fracture treated by internal fixation and quadratus femoris based muscle pedicle bone grafting. Materials and Methods: Open reduction and internal fixation with muscle pedicle grafting was done in 32 patients. The age of patients varied from 14-62 years (average age 45 years with male to female ratio of 13:3. Twenty-nine fractures were more than three weeks old. All the cases were treated by Meyers′ procedure. The fracture was internally fixed after open reduction and then a muscle pedicle graft was applied. It was supplemented by cancellous bone graft in seven cases. Fixation was done by parallel cancellous lag screws ( n = 19, crossed Garden′s screws ( n = 7, parallel Asnis screws ( n = 5 and Moore′s pin ( n = 1.Quadratus femoris muscle pedicle graft was used in 32 cases. In the initial 12 cases the graft was fixed with circumferential proline sutures, but later, to provide a secure fixation, the graft was fixed with a cancellous screw ( n = 20. Postoperative full weight bearing was deferred to an average of 10 weeks. Results: Union was achieved in 26/29 (89.65% cases which could be followed for an average period of 3.4 years, (2-8.5 years with good functional results and had the ability to squat and sit cross-legged. Results were based on hip rating system given by Salvatti and Wilson. The results were excellent in 15 cases, good in four cases, fair in four cases and poor in six cases. Complications were avascular necrosis ( n = 2, transient foot drop ( n = 2, coxa-vara ( n = 1 and temporary loss of scrotal sensation ( n = 1. Conclusion: Muscle pedicle bone grafting with

The Omental Pedicle Flap in Dogs Revised and Refined: A Cadaver Study.

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Doom, Marjan; Cornillie, Pieter; Simoens, Paul; Huyghe, Stephanie; de Rooster, Hilde

2016-08-01

To expand current knowledge on the canine omental vasculature and refine the existing lengthening technique of the canine omentum. Ex vivo study. Canine cadavers (n=20). In 10 canine cadavers the omental arteries were mapped using intravascular latex injection and these results were used to create an omental pedicle flap based on the splenic artery in 10 additional cadavers. The operating range of the flap was recorded with particular attention to the main regions of interest for omental transposition in dogs (axillary and inguinal regions). The superficial and deep omental leaves were each predominantly supplied by a left and a right marginal omental artery that anastomosed near the caudal omental border into a superficial and a deep omental arch, respectively. Anastomoses between arteries of the superficial and the deep omental leaves were weak and inconsistent, except for 1 anastomosis that was found in 8 of 10 dogs. By transposing the intact omentum, the right axilla could be reached in 3 dogs, both axillae in 1 dog, and both groins in all cadavers. In all cases, the omental pedicle reached to and beyond the axillary and inguinal regions. By unfolding the pedicle leaves, the width of the pedicle tip could be doubled. When lengthening the omentum is necessary to reach extra-abdominal structures, the omental pedicle flap based on the splenic artery appears to preserve the omental vascular supply. These observations warrant further clinical trials to evaluate this new omtental flap technique in vivo. © Copyright 2016 by The American College of Veterinary Surgeons.

Indoor Navigation from Point Clouds: 3d Modelling and Obstacle Detection

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Díaz-Vilariño, L.; Boguslawski, P.; Khoshelham, K.; Lorenzo, H.; Mahdjoubi, L.

2016-06-01

In the recent years, indoor modelling and navigation has become a research of interest because many stakeholders require navigation assistance in various application scenarios. The navigational assistance for blind or wheelchair people, building crisis management such as fire protection, augmented reality for gaming, tourism or training emergency assistance units are just some of the direct applications of indoor modelling and navigation. Navigational information is traditionally extracted from 2D drawings or layouts. Real state of indoors, including opening position and geometry for both windows and doors, and the presence of obstacles is commonly ignored. In this work, a real indoor-path planning methodology based on 3D point clouds is developed. The value and originality of the approach consist on considering point clouds not only for reconstructing semantically-rich 3D indoor models, but also for detecting potential obstacles in the route planning and using these for readapting the routes according to the real state of the indoor depictured by the laser scanner.

INDOOR NAVIGATION FROM POINT CLOUDS: 3D MODELLING AND OBSTACLE DETECTION

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L. Díaz-Vilariño

2016-06-01

Full Text Available In the recent years, indoor modelling and navigation has become a research of interest because many stakeholders require navigation assistance in various application scenarios. The navigational assistance for blind or wheelchair people, building crisis management such as fire protection, augmented reality for gaming, tourism or training emergency assistance units are just some of the direct applications of indoor modelling and navigation. Navigational information is traditionally extracted from 2D drawings or layouts. Real state of indoors, including opening position and geometry for both windows and doors, and the presence of obstacles is commonly ignored. In this work, a real indoor-path planning methodology based on 3D point clouds is developed. The value and originality of the approach consist on considering point clouds not only for reconstructing semantically-rich 3D indoor models, but also for detecting potential obstacles in the route planning and using these for readapting the routes according to the real state of the indoor depictured by the laser scanner.

[Comparison of pedicle and free tissue transfers in the German DRG system].

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Lotter, O; Stahl, S; Hohenstein, C; Schaller, H-E; Jaminet, P

2011-12-01

Diagnosis-Related Groups (DRGs) are a patient classification system grouping related types of patients to the resources they have consumed. In this analysis, we compared pedicle and free flaps in plastic and reconstructive surgery in the actual German DRG system. After grouping common flaps while systematically modifying the diagnosis, the operative procedure(s), and the receptor site, reimbursement and thresholds of length of stay were identified. The mean value of the average length of stay was higher in free flaps as compared to pedicle flaps (15 vs. 9 days) and the mean reimbursement in free flaps was almost twice as high as in pedicle flaps (8 936 € vs. 4 582 €). Regarding the diagnosis, third-grade open fractures in pedicle flaps and full-thickness burns in free flaps are in the vanguard of reimbursement. Higher DRG conformity is generally found with free flaps. Different possibilities in coding the procedures and the strong dependence on the underlying diagnosis lead to variations of remuneration and length of stay, which are not explainable and sometimes even seem paradoxical. Furthermore, mixed calculation creates DRGs that lose the ability to describe the real effort. © Georg Thieme Verlag KG Stuttgart · New York.

Utility of Glissonean Pedicle Transection for Surgical Treatment of Severe Liver Trauma

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Satoshi Koizumi

2017-04-01

Full Text Available The most common initial strategy for treatment of severe liver trauma is damage control in which hemostasis is achieved by perihepatic gauze packing and/or vascular embolization. However, we encounter patients in whom this strategy alone is not adequate. We have applied the principles of Glissonean pedicle transection, a technique that was originally devised to ensure safe and quick performance of planned hepatectomy for liver cancer, to 3 cases of severe liver trauma. We performed Glissonean pedicle ligation during damage control surgery in 2 patients and Glissonean pedicle transection during the definitive surgery in 1 patient. We describe the approaches and our experience with them, including operation times and outcomes. From our experience thus far, it seems that 8–12 h after the damage control procedure is appropriate for performing the definitive surgery. Although there are some problems posed by this strategy and cases to which it will not be applicable, the method seems to be particularly useful for cases of severe liver trauma in which the damage is extensive and involves the Glissonean pedicles near the hepatic hilus. We describe our 3 cases in detail and review our experience in light of the available literature.

Clinical evaluation of patients undergoing dynamic pedicle fixation in lumbar spine

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Felipe José Vieira Figueiredo

2015-06-01

Full Text Available OBJECTIVE: To evaluate the preliminary clinical results and complications in patients undergoing dynamic pedicle fixation of the spine in the treatment of a specific group of degenerative lumbar disease.METHODS: In this preliminary retrospective study, we selected 14 patients who underwent surgery from January 2006 to July 2010. We selected only patients with spondylolisthesis without spondylolysis (Grade 1 Meyerding. All patients underwent surgery at one level and the levels mostly addressed were: L3-L4, L4-L5 or L5-S1. The approach was the same in all patients (posterior median approach with preservation of the posterior elements. All patients underwent intense conservative treatment without clinical response and the same research algorithm preoperatively.RESULTS: Retrospective analysis of Oswestry questionnaire after selection and publication of results of 14 patients with Grade 1 spondylolisthesis who underwent dynamic pedicle stabilization in a total of 56 pedicle screws, being all in one level. There was no fracture of any screws, the mean hospital stay was a day and a half, no patient required blood transfusion and there were no cases of infection, with significant improvement in the Oswestry questionnaire.CONCLUSION: In this study, the dynamic pedicle stabilization method proved to be an excellent treatment option when surgical criteria are strictly adhered to. There was an improvement in Oswestry values, lower hospital stay and low rate of complications, consisting of an alternative in motion preservation surgery.

Isolated unilateral vertebral pedicle fracture caused by a back massage in an elderly patient: a case report and literature review.

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Guo, Zhiping; Chen, Wei; Su, Yanling; Yuan, Junhui; Zhang, Yingze

2013-11-01

The vertebral pedicle injuries are clinically common. However, the isolated vertebral pedicle fracture with intact vertebral bodies is a rare lesion. We reported a case of a 66-year-old man who experienced a pedicle fracture after a back massage. The patient sustained osteoporosis, long-existing low back pain and nerve compression symptoms without antecedent major trauma. Imaging findings demonstrated an isolated unilateral L5 vertebral pedicle fracture with intact vertebral bodies, spinal canal stenosis at the L4-5 levels, bulging annulus fibrosus at the L4-S1 levels, bilateral spondylolysis and an L5/S1 spondylolisthesis. The patient underwent L4-S1 decompressive laminectomy, L5/S1 discectomy and neurolysis, and reduction and fixation of the L5 vertebral pedicle fracture and L5/S1 spondylolisthesis using the pedicle nail system. At follow-ups, the patient showed good recovery without pain or numbness in the low back and bilateral lower extremities. This study raises the awareness of a complication of alternative medicine and the possibility of a pedicle fracture caused by a low-energy trauma.

Osteonecrosis of femoral head: Treatment by core decompression and vascular pedicle grafting

Directory of Open Access Journals (Sweden)

Babhulkar Sudhir

2009-01-01

Full Text Available Background: Femoral head-preserving core decompression and bone grafting have shown excellent result in preventing collapse. The use of vascularized grafts have shown better clinical results. The vascular pedicle bone graft is an easy to perform operation and does not require special equipment. We analyzed and report a series of patients of osteonecrosis of femoral head treated by core decompression and vascular pedicle grafting of part of iliac crest based on deep circumflex iliac vessels. Materials and Methods: The article comprises of the retrospective study of 31 patients of osteonecrosis of femoral head in stage II and III treated with core decompression and vascular pedicle grafting by using part of iliac crest with deep circumflex iliac vessels from January 1990 to December 2005. The young patients with a mean age 32 years (18-52 years with a minimum follow-up of five years were included for analysis. Sixteen patients had osteonecrosis following alcohol abuse, 12 patients following corticosteroid consumption, 3 patients had idiopathic osteonecrosis. Nine patients were stage IIB, and 22 patients were stage IIIC according to ARCO′s system. The core decompression and vascular pedicle grafting was performed by anterior approach by using part of iliac crest with deep circumflex iliac vessels. Results: Digital subtraction arteriography performed in 9 patients at the end of 12 weeks showed the patency of deep circumflex artery in all cases, and bone scan performed in 6 other patients showed high uptake in the grafted area of the femoral head proving the efficacy of the operative procedure. Out of 31 patients, only one patient progressed to collapse and total joint replacement was advised. At the final follow up period of 5-8 years, Harris Hip Score improved mean ± SD of 28.2 ± 6.4 ( p < 0.05. Forty-eight percent of patients had an improvement in Harris Hip Score of more that 28 points. Conclusion: The core decompression and vascular pedicle

Intelligent navigation to improve obstetrical sonography.

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Yeo, Lami; Romero, Roberto

2016-04-01

'Manual navigation' by the operator is the standard method used to obtain information from two-dimensional and volumetric sonography. Two-dimensional sonography is highly operator dependent and requires extensive training and expertise to assess fetal anatomy properly. Most of the sonographic examination time is devoted to acquisition of images, while 'retrieval' and display of diagnostic planes occurs rapidly (essentially instantaneously). In contrast, volumetric sonography has a rapid acquisition phase, but the retrieval and display of relevant diagnostic planes is often time-consuming, tedious and challenging. We propose the term 'intelligent navigation' to refer to a new method of interrogation of a volume dataset whereby identification and selection of key anatomical landmarks allow the system to: 1) generate a geometrical reconstruction of the organ of interest; and 2) automatically navigate, find, extract and display specific diagnostic planes. This is accomplished using operator-independent algorithms that are both predictable and adaptive. Virtual Intelligent Sonographer Assistance (VIS-Assistance®) is a tool that allows operator-independent sonographic navigation and exploration of the surrounding structures in previously identified diagnostic planes. The advantage of intelligent (over manual) navigation in volumetric sonography is the short time required for both acquisition and retrieval and display of diagnostic planes. Intelligent navigation technology automatically realigns the volume, and reorients and standardizes the anatomical position, so that the fetus and the diagnostic planes are consistently displayed in the same manner each time, regardless of the fetal position or the initial orientation. Automatic labeling of anatomical structures, subject orientation and each of the diagnostic planes is also possible. Intelligent navigation technology can operate on conventional computers, and is not dependent on specific ultrasound platforms or on the

Percutaneous Sacroiliac Screw Placement: A Prospective Randomized Comparison of Robot-assisted Navigation Procedures with a Conventional Technique

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Wang, Jun-Qiang; Wang, Yu; Feng, Yun; Han, Wei; Su, Yong-Gang; Liu, Wen-Yong; Zhang, Wei-Jun; Wu, Xin-Bao; Wang, Man-Yi; Fan, Yu-Bo

2017-01-01

wire attempts in the robot-assisted group was significantly less than that in the freehand group (median [Q1, Q3]: 1.0 [1.0,1.0] time vs. median [Q1, Q3]: 7.0 [1.0, 9.0] times; χ2 = 15.771, respectively, P < 0.001). The instrumented SI levels did not differ between both groups (from S1 to S2, χ2 = 4.760, P = 0.093). Conclusions: Accuracy of the robot-assisted technique was superior to that of the freehand technique. Robot-assisted navigation is safe for unstable posterior pelvic ring stabilization, especially in S1, but also in S2. SI screw insertion with robot-assisted navigation is clinically feasible. PMID:29067950

Spinal pedicle subtraction osteotomy for fixed sagittal imbalance patients

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Hyun, Seung-Jae; Kim, Yongjung J; Rhim, Seung-Chul

2013-01-01

In addressing spinal sagittal imbalance through a posterior approach, the surgeon now may choose from among a variety of osteotomy techniques. Posterior column osteotomies such as the facetectomy or Ponte or Smith-Petersen osteotomy provide the least correction, but can be used at multiple levels with minimal blood loss and a lower operative risk. Pedicle subtraction osteotomies provide nearly 3 times the per-level correction of Ponte/Smith-Petersen osteotomies; however, they carry increased technical demands, longer operative time, and greater blood loss and associated significant morbidity, including neurological injury. The literature focusing on pedicle subtraction osteotomy for fixed sagittal imbalance patients is reviewed. The long-term overall outcomes, surgical tips to reduce the complications and suggestions for their proper application are also provided. PMID:24340276

The feasibility of inserting a C1 pedicle screw in patients with ponticulus posticus: a retrospective analysis of eleven patients.

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Zhang, Xin-Liang; Huang, Da-Geng; Wang, Xiao-Dong; Zhu, Jin-Wen; Li, Yi-Bing; He, Bao-Rong; Hao, Ding-Jun

2017-04-01

Ponticulus posticus is a common anatomic variation that can be mistaken for a broad posterior arch during C1 pedicle screw placement. When the atlas lateral mass screws are placed via the posterior arch, injury to the vertebral artery may result. To our knowledge, there are few clinical studies that have analyzed the feasibility of C1 pedicle screw fixation in patients with ponticulus posticus, in clinical practice. To evaluate the feasibility of inserting a C1 pedicle screw in patients with ponticulus posticus. Between January 2008 and January 2012, 11 consecutive patients with atlantoaxial instability, and with a ponticulus posticus at C1, underwent posterior fusion surgery in our institution. According to preoperative computed tomography (CT) reconstruction, a complete ponticulus posticus was found unilaterally in nine patients and bilaterally in two. Postoperative CT reconstructive imaging was performed to assess whether C1 pedicle screw placement was successful. Patients were followed up at regular intervals and evaluated for symptoms of ponticulus posticus syndrome. Thirteen C1 pedicles (atlas vertebral artery groove), each with a complete ponticulus posticus, were successfully inserted with thirteen 3.5- or 4.0-mm diameter pedicle screws, without resection of the bony anomaly. No intraoperative complications (venous plexus, vertebral artery, or spinal cord injury) occurred. The mean follow-up period was 21 (range 14-30) months. Postoperative CT reconstructive images showed that all 13 pedicle screws were inserted in the C1 pedicles without destruction of the atlas pedicle cortical bone. In the follow-up period, none of the patients demonstrated clinical symptoms of ponticulus posticus syndrome or developed bone fusion. Three-dimensional CT imaging should be considered prior to C1 pedicle screw fixation in patients with ponticulus posticus, to avoid mistaking the ponticulus posticus for a widened dorsal arch of the atlas. If there is no ponticulus posticus

Safety of lumbar spine radiofrequency procedures in the presence of posterior pedicle screws: technical report of a cadaver study.

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Gazelka, Halena M; Welch, Tasha L; Nassr, Ahmad; Lamer, Tim J

2015-05-01

To determine whether the thermal energy associated with lumbar spine radiofrequency neurotomy (RFN) performed near titanium and stainless steel pedicle screws is conducted to the pedicle screws or adjacent tissues, or both, thus introducing potential for thermal damage to those tissues. Cadaver study. Cadaver laboratory equipped with fluoroscopy, surgical spine implements, and radiofrequency generator. No live human subject; a fresh frozen (and thawed) cadaver torso was used for the study. Titanium and stainless steel pedicle screws were placed in the lumbar spine of a fresh frozen cadaver torso with real-time fluoroscopic guidance. Conventional RFN cannula placement was performed at the level of pedicle screws and a control (nonsurgically altered) lumbar level. Neurotomy was performed with conventional radiofrequency lesioning parameters. Temperatures were recorded at multiple sites through thermistor probes. Direct contact of the radiofrequency cannula with the pedicle screws during conventional RFN produced a substantial increase in temperature in the surrounding soft tissues. A small increase in temperature occurred at the same sites at the control level. Titanium and stainless steel pedicle screws are capable of sustaining large increases in temperature when the radiofrequency probe comes in contact with the screw. These results are suggestive that pedicle screws could serve as a possible source of tissue heating and thermal injury during RFN. Wiley Periodicals, Inc.

Risk factors for pedicled flap necrosis in hand soft tissue reconstruction: a multivariate logistic regression analysis.

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Gong, Xu; Cui, Jianli; Jiang, Ziping; Lu, Laijin; Li, Xiucun

2018-03-01

Few clinical retrospective studies have reported the risk factors of pedicled flap necrosis in hand soft tissue reconstruction. The aim of this study was to identify non-technical risk factors associated with pedicled flap perioperative necrosis in hand soft tissue reconstruction via a multivariate logistic regression analysis. For patients with hand soft tissue reconstruction, we carefully reviewed hospital records and identified 163 patients who met the inclusion criteria. The characteristics of these patients, flap transfer procedures and postoperative complications were recorded. Eleven predictors were identified. The correlations between pedicled flap necrosis and risk factors were analysed using a logistic regression model. Of 163 skin flaps, 125 flaps survived completely without any complications. The pedicled flap necrosis rate in hands was 11.04%, which included partial flap necrosis (7.36%) and total flap necrosis (3.68%). Soft tissue defects in fingers were noted in 68.10% of all cases. The logistic regression analysis indicated that the soft tissue defect site (P = 0.046, odds ratio (OR) = 0.079, confidence interval (CI) (0.006, 0.959)), flap size (P = 0.020, OR = 1.024, CI (1.004, 1.045)) and postoperative wound infection (P < 0.001, OR = 17.407, CI (3.821, 79.303)) were statistically significant risk factors for pedicled flap necrosis of the hand. Soft tissue defect site, flap size and postoperative wound infection were risk factors associated with pedicled flap necrosis in hand soft tissue defect reconstruction. © 2017 Royal Australasian College of Surgeons.

Lumbar pedicle screw placement: Using only AP plane imaging

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Anil Sethi

2012-01-01

Conclusion: Placement of pedicle screws under fluoroscopic guidance using AP plane imaging alone with tactile guidance is safe, fast, and reliable. However, a good understanding of the radiographic landmarks is a prerequisite.

Reconstruction of trochanteric pressure sores with pedicled anterolateral thigh myocutaneous flaps.

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Wang, Chih-Hsin; Chen, Shih-Yi; Fu, Ju-Peng; Dai, Niann-Tzyy; Chen, Shao-Liang; Chen, Tim-Mo; Chen, Shyi-Gen

2011-05-01

To provide an alternative choice for covering trochanteric pressure sores, we report on a modified pedicle anterolateral thigh (ALT) myocutaneous flap based on the descending branch of the lateral circumflex femoral artery. From August 2007 to January 2010, 20 consecutive patients (10 men and 10 women) underwent 21 pedicled ALT myocutaneous flaps for reconstruction of trochanteric pressure sores. The flap was designed and elevated, resembling the ALT perforator flap including part of the vastus lateralis muscle but without skeletonisation of the perforators. The mean age of patients was 79.4 years (range: 46-103). The mean follow-up period was 13.9 months (range: 3-32). The flaps were 8-21 cm long and 5-11 cm wide. All flaps healed without major complications. All donor sites were closed primarily without skin grafting and showed good aesthetic results. No recurrence was observed. This modified design of pedicled ALT myocutaneous flap without skeletonisation of perforators is a reliable and easily harvested flap for reconstruction of trochanteric pressure sores with limited morbidity. Crown Copyright © 2010. Published by Elsevier Ltd. All rights reserved.

Pedicle screw-rod fixation: a feasible treatment for dogs with severe degenerative lumbosacral stenosis.

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Tellegen, Anna R; Willems, Nicole; Tryfonidou, Marianna A; Meij, Björn P

2015-12-07

Degenerative lumbosacral stenosis is a common problem in large breed dogs. For severe degenerative lumbosacral stenosis, conservative treatment is often not effective and surgical intervention remains as the last treatment option. The objective of this retrospective study was to assess the middle to long term outcome of treatment of severe degenerative lumbosacral stenosis with pedicle screw-rod fixation with or without evidence of radiological discospondylitis. Twelve client-owned dogs with severe degenerative lumbosacral stenosis underwent pedicle screw-rod fixation of the lumbosacral junction. During long term follow-up, dogs were monitored by clinical evaluation, diagnostic imaging, force plate analysis, and by using questionnaires to owners. Clinical evaluation, force plate data, and responses to questionnaires completed by the owners showed resolution (n = 8) or improvement (n = 4) of clinical signs after pedicle screw-rod fixation in 12 dogs. There were no implant failures, however, no interbody vertebral bone fusion of the lumbosacral junction was observed in the follow-up period. Four dogs developed mild recurrent low back pain that could easily be controlled by pain medication and an altered exercise regime. Pedicle screw-rod fixation offers a surgical treatment option for large breed dogs with severe degenerative lumbosacral stenosis with or without evidence of radiological discospondylitis in which no other treatment is available. Pedicle screw-rod fixation alone does not result in interbody vertebral bone fusion between L7 and S1.

Intraoperative Spinal Navigation for the Removal of Intradural Tumors: Technical Notes.

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Stefini, Roberto; Peron, Stefano; Mandelli, Jaime; Bianchini, Elena; Roccucci, Paolo

2017-08-05

In recent years, spinal surgery has incorporated the many advantages of navigation techniques to facilitate the placement of pedicle screws during osteosynthesis, mainly for degenerative diseases. However, spinal intradural tumors are not clearly visible by intraoperative fluoroscopy or computed tomography scans, thereby making navigation necessary. To evaluate the use of spinal navigation for the removal of intradural and spinal cord tumors using spinal magnetic resonance imaging (MRI) merged with intraoperative 3-dimensional (3-D) fluoro images. After fixing the patient reference frame on the spinous process, the 3-D fluoro images were obtained in the surgical room. Using this image as the reference, the preoperative volumetric MRI images and intraoperative 3-D fluoro images were merged using automated software or manually. From January to July 2016, we performed 10 navigated procedures for intradural spinal tumors by merging MRI and 3-D fluoro images. Nine patients had an intradural extramedullary tumor, 6 had neurinomas, and 3 had meningiomas; 1 patient had an intramedullary spinal cord metastasis. The surgically demonstrated benefits of spinal navigation for the removal of intradural tumors include the decreased risk of surgery at the wrong spinal level, a minimal length of skin incision and muscle strip, and a reduction in bone removal extension. Furthermore, this technique offers the advantage of opening the dura as much as is necessary and, in the case of intrinsic spinal cord tumors, it allows the tumor to be centered. Otherwise, this would not be visible, thus enabling the precise level and the posterior midline sulcus to be determined when performing a mielotomy. Copyright © 2017 by the Congress of Neurological Surgeons

Omental pedicle transposition and suture repair of peripheral nerve ...

African Journals Online (AJOL)

Abu wael

This study aimed to compare the effectiveness of omental pedicle transposition and ... Assessment of the nerve regeneration was based on functional (motor and sensory), ..... peripheral nerve fibers regenerating after crush, multiple crush, and.

Use of a life-size three-dimensional-printed spine model for pedicle screw instrumentation training.

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Park, Hyun Jin; Wang, Chenyu; Choi, Kyung Ho; Kim, Hyong Nyun

2018-04-16

Training beginners of the pedicle screw instrumentation technique in the operating room is limited because of issues related to patient safety and surgical efficiency. Three-dimensional (3D) printing enables training or simulation surgery on a real-size replica of deformed spine, which is difficult to perform in the usual cadaver or surrogate plastic models. The purpose of this study was to evaluate the educational effect of using a real-size 3D-printed spine model for training beginners of the free-hand pedicle screw instrumentation technique. We asked whether the use of a 3D spine model can improve (1) screw instrumentation accuracy and (2) length of procedure. Twenty life-size 3D-printed lumbar spine models were made from 10 volunteers (two models for each volunteer). Two novice surgeons who had no experience of free-hand pedicle screw instrumentation technique were instructed by an experienced surgeon, and each surgeon inserted 10 pedicle screws for each lumbar spine model. Computed tomography scans of the spine models were obtained to evaluate screw instrumentation accuracy. The length of time in completing the procedure was recorded. The results of the latter 10 spine models were compared with those of the former 10 models to evaluate learning effect. A total of 37/200 screws (18.5%) perforated the pedicle cortex with a mean of 1.7 mm (range, 1.2-3.3 mm). However, the latter half of the models had significantly less violation than the former half (10/100 vs. 27/100, p 3D-printed spine model can be an excellent tool for training beginners of the free-hand pedicle screw instrumentation.

Are We Underestimating the Significance of Pedicle Screw Misplacement?

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Sarwahi, Vishal; Wendolowski, Stephen F; Gecelter, Rachel C; Amaral, Terry; Lo, Yungtai; Wollowick, Adam L; Thornhill, Beverly

2016-05-01

A retrospective review of charts, x-rays (XRs) and computed tomography (CT) scans was performed. To evaluate the accuracy of pedicle screw placement using a novel classification system to determine potentially significant screw misplacement. The accuracy rate of pedicle screw (PS) placement varies from 85% to 95% in the literature. This demonstrates technical ability but does not represent the impact of screw misplacement on individual patients. This study quantifies the rate of screw misplacement on a per-patient basis to highlight its effect on potential morbidity. A retrospective review of charts, XRs and low-dose CT scans of 127 patients who underwent spinal fusion with pedicle screws for spinal deformity was performed. Screws were divided into four categories: screws at risk (SAR), indeterminate misplacements (IMP), benign misplacements (BMP), accurately placed (AP). A total of 2724 screws were placed in 127 patients. A total of 2396 screws were placed accurately (87.96%). A total of 247 screws (9.07%) were BMP, 52 (1.91%) were IMP, and 29 (1.06%) were considered SAR. Per-patient analysis showed 23 (18.11%) of patients had all screws AP. Thirty-five (27.56%) had IMP and 18 (14.17%) had SAR. Risk factor analysis showed smaller Cobb angles increased likelihood of all screws being AP. Sub-analysis of adolescent idiopathic scoliotic patients showed no curve or patient characteristic that correlated with IMP or SAR. Over 40% of patients had screws with either some/major concern. Overall reported screw misplacement is low, but it does not reflect the potential impact on patient morbidity. Per-patient analysis reveals more concerning numbers toward screw misplacement. With increasing pedicle screw usage, the number of patients with misplaced screws will likely increase proportionally. Better strategies need to be devised for evaluation of screw placement, including establishment of a national database of deformity surgery, use of intra-operative image guidance, and

A computed tomography morphometric study of occipital bone and C2 pedicle anatomy for occipital-cervical fusion.

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King, Nicolas K K; Rajendra, Tiruchelvarayan; Ng, Ivan; Ng, Wai Hoe

2014-01-01

Occipital-cervical fusion (OCF) has been used to treat instability of the occipito-cervical junction and to provide biomechanical stability after decompressive surgery. The specific areas that require detailed morphologic knowledge to prevent technical failures are the thickness of the occipital bone and diameter of the C2 pedicle, as the occipital midline bone and the C2 pedicle have structurally the strongest bone to provide the biomechanical purchase for cranio-cervical instrumentation. The aim of this study was to perform a quantitative morphometric analysis using computed tomography (CT) to determine the variability of the occipital bone thickness and C2 pedicle thickness to optimize screw placement for OCF in a South East Asian population. Thirty patients undergoing cranio-cervical junction instrumentation during the period 2008-2010 were included. The thickness of the occipital bone and the length and diameter of the C2 pedicle were measured based on CT. The thickest point on the occipital bone was in the midline with a maximum thickness below the external occipital protuberance of 16.2 mm (±3.0 mm), which was thicker than in the Western population. The average C2 pedicle diameter was 5.3 mm (±2.0 mm). This was smaller than Western population pedicle diameters. The average length of the both pedicles to the midpoint of the C2 vertebral body was 23.5 mm (±3.3 mm on the left and ±2.3 mm on the right). The results of this first study in the South East Asian population should help guide and improve the safety in occipito-cervical region instrumentation. Thus reducing the risk of technical failures and neuro-vascular injury.

Application of Intraoperative CT-Guided Navigation in Simultaneous Minimally Invasive Anterior and Posterior Surgery for Infectious Spondylitis

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Meng-Huang Wu

2017-01-01

Full Text Available This study was aimed at evaluating the safety and efficacy of using intraoperative computed tomography- (iCT- guided navigation in simultaneous minimally invasive anterior and posterior surgery for infectious spondylitis. Nine patients with infectious spondylitis were enrolled in this study. The average operative time was 327.6 min (range, 210–490 and intraoperative blood loss was 407 cc (range, 50–1,200. The average duration of hospital stay was 48.9 days (range, 11–76. Out of a total of 54 pedicle screws employed, 53 screws (98.1% were placed accurately. A reduced visual analog scale on back pain (from 8.2 to 2.2 and Oswestry disability index (from 67.1% to 25.6% were found at the 2-year follow-up. All patients had achieved resolution of spinal infection with reduced average erythrocyte sedimentation rate (from 83.9 to 14.1 mm/hr and average C-reactive protein (from 54.4 to 4.8 mg/dL. Average kyphotic angle correction was 10.5° (range, 8.4°–12.6° postoperatively and 8.5° (range, 6.9°–10.1° after 2 years. In conclusion, the current iCT-guided navigation approach has been demonstrated to be an alternative method during simultaneous minimally invasive anterior and posterior surgery for infectious spondylitis. It can provide a good intraoperative orientation and visualization of anatomic structures and also a high pedicle screw placement accuracy in patient’s lateral decubitus position.

Significance of magnetic resonance imaging signal change in the pedicle in the management of pediatric lumbar spondylolysis.

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Sakai, Toshinori; Sairyo, Koichi; Mima, Seiichi; Yasui, Natsuo

2010-06-15

Prospective study. To investigate the time course of signal changes in the adjacent pedicle in fresh pediatric lumbar spondylolysis. A recent study reported that high signal change (HSC) on T2-magnetic resonance image (MRI) in the pedicle adjacent to the pars interarticularis could be an indicator of early spondylolysis. In addition, the HSC-positive pars defects showed significant better bony healing than the HSC-negative pars defects. However, there has been no report on the time course and the duration of HSC. We prospectively investigated 10 boys and 5 girls with fresh lumbar spondylolysis showing HSC in the adjacent pedicle. Their mean age was 15.1 years, ranging from 10 to 17 years. Two patients had multilevel unilateral spondylolysis. Among 15 patients, HSC was found in 22 (12 unilateral and 5 bilateral) pedicles. At the first presentation, the diagnosis of spondylolysis was made based on the plain radiograph findings, multidetector computed tomograms (CTs), and MRI. Every month from the first presentation, follow-up MRIs were taken. When HSC disappeared, multidetector CT was taken to confirm bony healing of the pars defect. Bony healing of the pars was obtained in 21 out of 22 defects. The bony healing rate was 95.6%. In 19 pedicles of 12 patients, HSC gradually diminished by every month until it disappeared 3 months later, and radiologic osseous healing was confirmed by CT in all but 1 patient. In the 3 remaining pedicles of 3 patients, HSC took more than 4 months to disappear. In this study, HSC disappeared in most pedicles on the 3-month follow-up MRI. In patients who did not comply with treatment, HSC tended to last longer. These results led us to hypothesize that MRI at the third month during follow-up can indicate whether the conservative treatment is being successful or not.

reduction mammoplasty using inferior pedicle in heavy breasts

African Journals Online (AJOL)

2011-09-09

Sep 9, 2011 ... sexual relationships. Reduction mammoplasty procedure provides weight and volume reduction of the breast as well as enhancement of the aesthetic appearance of the breasts. In this study, the inferior pedicle technique was used in reduction of thirty five patients over the last four years with macromastia.

[Pedicled versus free TRAM flap for breast reconstruction].

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Galla, T J; Lukas, B; Feller, A M

1999-03-01

In breast reconstruction, the free TRAM-flap offers many advantages over the pedicled TRAM-flap. Due to its superior perfusion, the free flap rarely develops necrosis. Shaping of the flap is easier due to the lack of the thick muscle pedicle. Because the rectus muscle is spared, there is minimal donor site morbidity. However, the necessary microvascular anastomoses reduced the acceptance of the free TRAM-flap. During a 13-months period, 51 breast reconstructions were performed in 41 patients, 31 unilateral and ten bilateral. 45 flaps served for delayed reconstruction and six flaps for immediate reconstruction. The operations were performed by two teams working simultaneously. The average operating time was 3.9 hours for unilateral and 6.9 hours for bilateral delayed reconstruction. For immediate reconstruction, 6.2 and 6.3 hours were required for uni- and bilateral procedures, respectively. In 38 flaps, the thoracodorsal vessels served as recipient vessels; 13 flaps were anastomosed to the internal mammary artery and vein. Postoperative complications were observed in 13 patients. Three vessel anastomoses had to be revised. In one flap, a partial necrosis occurred; in two flaps hematoma evacuation was necessary. Two patients suffered from fat necroses at the abdomen and one umbilicus was lost. Skin irritations and seromas at the abdomen occurred in five patients. Pulmonary embolism was diagnosed in one patient three weeks postoperatively. Abdominal hernias or bulging in the epigastric area were not observed up to 15 months after reconstruction. These results reveal a low complication rate for breast reconstruction with the free TRAM-flap. The advantages of this technique as compared to the pedicled technique are discussed.

Enabling Autonomous Navigation for Affordable Scooters.

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Liu, Kaikai; Mulky, Rajathswaroop

2018-06-05

Despite the technical success of existing assistive technologies, for example, electric wheelchairs and scooters, they are still far from effective enough in helping those in need navigate to their destinations in a hassle-free manner. In this paper, we propose to improve the safety and autonomy of navigation by designing a cutting-edge autonomous scooter, thus allowing people with mobility challenges to ambulate independently and safely in possibly unfamiliar surroundings. We focus on indoor navigation scenarios for the autonomous scooter where the current location, maps, and nearby obstacles are unknown. To achieve semi-LiDAR functionality, we leverage the gyros-based pose data to compensate the laser motion in real time and create synthetic mapping of simple environments with regular shapes and deep hallways. Laser range finders are suitable for long ranges with limited resolution. Stereo vision, on the other hand, provides 3D structural data of nearby complex objects. To achieve simultaneous fine-grained resolution and long range coverage in the mapping of cluttered and complex environments, we dynamically fuse the measurements from the stereo vision camera system, the synthetic laser scanner, and the LiDAR. We propose solutions to self-correct errors in data fusion and create a hybrid map to assist the scooter in achieving collision-free navigation in an indoor environment.

Experimental study of pedicle screw stability on low BMD vertebrae

International Nuclear Information System (INIS)

Li Qi; Yang Huilin; Tang Tiansi; Wu Yiwei; Wang Yijin

2005-01-01

Objective: To conduct biomechanical study of different pedicle screws stability on spinal specimen, discuss the relationship between design parameter of screw, insertion torgue and BMD, establish the theoretical foundation for application of pedicle screw on osteoporotic patients. Methods: Six fixed lumbar cadavers were collected, the effects of design parameter, insertion torque and etc on fixation stability were determined under various BMD by using biomechanical ways. Results: According to in vitro study: (1) There was a significant difference among pullout strength of all screws (P 2 >U 1 >SF 1 >SF 2 >RF. Conclusions: There is a close correlated between type of screw, BMD and stability. The U-type screw displays the best fixation effect on specimen of low BMD. (authors)

The accuracy of the lateral vertebral notch-referred pedicle screw insertion technique in subaxial cervical spine: a human cadaver study.

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Luo, Jiaquan; Wu, Chunyang; Huang, Zhongren; Pan, Zhimin; Li, Zhiyun; Zhong, Junlong; Chen, Yiwei; Han, Zhimin; Cao, Kai

2017-04-01

This is a cadaver specimen study to confirm new pedicle screw (PS) entry point and trajectory for subaxial cervical PS insertion. To assess the accuracy of the lateral vertebral notch-referred PS insertion technique in subaxial cervical spine in cadaver cervical spine. Reported morphometric landmarks used to guide the surgeon in PS insertion show significant variability. In the previous study, we proposed a new technique (as called "notch-referred" technique) primarily based on coronal multiplane reconstruction images (CMRI) and cortical integrity after PS insertion in cadavers. However, the PS position in cadaveric cervical segment was not confirmed radiologically. Therefore, the difference between the pedicle trajectory and the PS trajectory using the notch-referred technique needs to be illuminated. Twelve cadaveric cervical spines were conducted with PS insertion using the lateral vertebral notch-referred technique. The guideline for entry point and trajectory for each vertebra was established based on the morphometric data from our previous study. After 3.5-mm diameter screw insertion, each vertebra was dissected and inspected for pedicle trajectory by CT scan. The pedicle trajectory and PS trajectory were measured and compared in axial plane. The perforation rate was assessed radiologically and was graded from ideal to unacceptable: Grade 0 = screw in pedicle; Grade I = perforation of pedicle wall less than one-fourth of the screw diameter; Grade II = perforation more than one-fourth of the screw diameter but less than one-second; Grade III = perforation more than one-second outside of the screw diameter. In addition, pedicle width between the acceptable and unacceptable screws was compared. A total of 120 pedicle screws were inserted. The perforation rate of pedicle screws was 78.3% in grade 0 (excellent PS position), 10.0% in grade I (good PS position), 8.3% in grade II (fair PS position), and 3.3% in grade III (poor PS position). The

scrotal reconstruction with a pedicled gracilis muscle flap after

African Journals Online (AJOL)

nonviable tissue is removed and a granulation bed suitable for .... The pedicled or free greater omental flap as well as scrotal tissue ... Bien-keem Tan, Mohammed ZulfikarRasheed,. WofflesT.L.Wu ... Honda Hsu Chih Ming Lin, Tzong-Bon Sun,.

Computer Navigation-aided Resection of Sacral Chordomas

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Yong-Kun Yang

2016-01-01

Full Text Available Background: Resection of sacral chordomas is challenging. The anatomy is complex, and there are often no bony landmarks to guide the resection. Achieving adequate surgical margins is, therefore, difficult, and the recurrence rate is high. Use of computer navigation may allow optimal preoperative planning and improve precision in tumor resection. The purpose of this study was to evaluate the safety and feasibility of computer navigation-aided resection of sacral chordomas. Methods: Between 2007 and 2013, a total of 26 patients with sacral chordoma underwent computer navigation-aided surgery were included and followed for a minimum of 18 months. There were 21 primary cases and 5 recurrent cases, with a mean age of 55.8 years old (range: 35-84 years old. Tumors were located above the level of the S3 neural foramen in 23 patients and below the level of the S3 neural foramen in 3 patients. Three-dimensional images were reconstructed with a computed tomography-based navigation system combined with the magnetic resonance images using the navigation software. Tumors were resected via a posterior approach assisted by the computer navigation. Mean follow-up was 38.6 months (range: 18-84 months. Results: Mean operative time was 307 min. Mean intraoperative blood loss was 3065 ml. For computer navigation, the mean registration deviation during surgery was 1.7 mm. There were 18 wide resections, 4 marginal resections, and 4 intralesional resections. All patients were alive at the final follow-up, with 2 (7.7% exhibiting tumor recurrence. The other 24 patients were tumor-free. The mean Musculoskeletal Tumor Society Score was 27.3 (range: 19-30. Conclusions: Computer-assisted navigation can be safely applied to the resection of the sacral chordomas, allowing execution of preoperative plans, and achieving good oncological outcomes. Nevertheless, this needs to be accomplished by surgeons with adequate experience and skill.

Evaluation of 99mTc-MDP bone imaging in monitoring the muscle-pedicle bone graft osteogenic activation

International Nuclear Information System (INIS)

Sang Shibiao; Wu Yiwei; Zhang Wei; Jiang Yimin; Chen Guangxiang; Dong Tianhua

2002-01-01

Nine mature and healthy dogs were divided into 4 groups randomly. The first group consists of 3 dogs, and the rest groups, 2 dogs. Self-control way was used. The left ilium was the experimental site, where the bone piece with sartorial muscle attached was cut from ilium. The right side served as control, where the graft bone from ilium was wrapped up with silica gel, then fixed subcutaneously. The pedicled bone pieces were retrieved in 2, 4, 6, 8 weeks after surgery, the size of graft bones from two sides were the same. Survival range, osteogenic formation of muscle-pedicle bone were examined by 99m Tc-MDP bone imaging and histological method to evaluate the clinical value of treatment of ischemic osteonecrosis of the femoral head with muscle-pedicle bone grafting. The results were as follows: 1. The part of bone attached by the sartorial survived, but osteonecrosis was observed at the location of 1.2-1.7 cm from attached point of muscle. 2. There were two forms observed in the course of osteogenic activation of muscle-pedicle bone. Under the reduction of mechanical stimulation and blood supply, bone marrow tissue was replaced by fibro-granulation tissue and new capillary in the survival part, while the survival bone of proximal part grew distally and gradually replace the dead bone of distal part. 3. Histological examination revealed that small amounts of fibro-granulation tissue and new capillary appeared in 2nd week, primary trabeculae appeared in 6th week, and in 8th week, some trabeculae recovered their normal appearance and osteogenic cell reduced remarkably. 4. Survival range of muscle-pedicle graft bone was directly proportional to the width of muscle pedicle. Therefore, radionuclide bone imaging and histological examination demonstrated that muscle-pedicle graft bone was a piece of bone with relatively poor blood supply, its effect is repairing necrosis and collapse of the femoral head is limited. 99m Tc-MDP bone imaging may be an effective and first

Comparative Analysis of Interval, Skipped, and Key-vertebral Pedicle Screw Strategies for Correction in Patients With Lenke Type 1 Adolescent Idiopathic Scoliosis.

Science.gov (United States)

Wang, Fei; Xu, Xi-Ming; Lu, Yanghu; Wei, Xian-Zhao; Zhu, Xiao-Dong; Li, Ming

2016-03-01

Pedicle screw constructs have become the mainstay for surgical correction in patients with spinal deformities. To reduce or avoid the risk of pedicle screw-based complications and to decrease the costs associated with pedicle screw instrumentation, some authors have introduced interval, skipped, and key-vertebral pedicle screw strategies for correction. However, there have been no comparisons of outcomes among these 3 pedicle screw-placement strategies.The aim of this study was to compare the correlative clinical outcomes of posterior correction and fusion with pedicle screw fixation using these 3 surgical strategies.Fifty-six consecutive patients with Lenke type 1 adolescent idiopathic scoliosis were included in this study. Twenty patients were treated with the interval pedicle screw strategy (IPSS), 20 with the skipped pedicle screw strategy (SPSS), and 16 with the key-vertebral pedicle screw strategy (KVPSS). Coronal and sagittal radiographs were analyzed before surgery, at 1 week after surgery, and at the last follow-up after surgery.There were no significant differences among the 3 groups regarding preoperative radiographic parameters. No significant difference was found between the IPSS and SPSS groups in correction of the main thoracic curve (70.8% vs 70.0%; P = 0.524). However, there were statistically significant differences between the IPSS and KVPSS groups (70.8% vs 64.9%) and between the SPSS and KVPSS groups (70.0% vs 64.9%) in correction of the main thoracic curve (P SPSS group was significantly higher than those in the IPSS (P SPSS and KVPSS groups (P SPSS, it can achieve a satisfactory clinical outcome and is more cost-effective.

Head and neck reconstruction with pedicled flaps in the free flap era.

Science.gov (United States)

Mahieu, R; Colletti, G; Bonomo, P; Parrinello, G; Iavarone, A; Dolivet, G; Livi, L; Deganello, A

2016-12-01

Nowadays, the transposition of microvascular free flaps is the most popular method for management of head and neck defects. However, not all patients are suitable candidates for free flap reconstruction. In addition, not every defect requires a free flap transfer to achieve good functional results. The aim of this study was to assess whether pedicled flap reconstruction of head and neck defects is inferior to microvascular free flap reconstruction in terms of complications, functionality and prognosis. The records of consecutive patients who underwent free flap or pedicled flap reconstruction after head and neck cancer ablation from 2006 to 2015, from a single surgeon, in the AOUC Hospital, Florence Italy were analysed. A total of 93 patients, the majority with oral cancer (n = 59), were included, of which 64 were pedicled flap reconstructions (69%). The results showed no significant differences in terms of functional outcome, flap necrosis and complications in each type of reconstruction. Multivariate regression analysis of flap necrosis and functional impairments showed no associated factors. Multivariate regression analysis of complicated flap healing showed that only comorbidities remained an explaining factor (p = 0.019). Survival analysis and proportional hazard regression analysis regarding cancer relapse or distant metastasis, showed no significant differences in prognosis of patients concerning both types of reconstruction. In this retrospective, non-randomised study cohort, pedicled flaps were not significantly inferior to free flaps for reconstruction of head and neck defects, considering functionality, complications and prognosis. © Copyright by Società Italiana di Otorinolaringologia e Chirurgia Cervico-Facciale, Rome, Italy.

Use of omental pedicle flap for radiation induced chest wall ulcer. A case report

International Nuclear Information System (INIS)

Takamori, Shinzo; Hayashi, Akihiro; Nagamatsu, Yoshinori; Tsushimi, Mutsuo; Ono, Hirofumi; Ohtsuka, Shoji

1995-01-01

A 79-year-old female with breast carcinoma undergoing a classical Halsted radical mastectomy followed by irradiation (total; 180 Gy) 20 years before developed a left anterior chest wall ulcer. The ulcer was 10.0 x 8.0 cm in size with osteolysis of 3rd, 4th and 5th ribs, exposed pericardium, and parietal pleura with a pleuro-cutaneous fistula. After thorough debridement, an omental pedicle flap was transposed onto the chest wall defect and subsequently covered using a split-skin graft. The omental pedicle flap was 90% effective in covering the pericardial defect and resulted in a complete closure of the pleuro-cutaneous fistula. This report emphasises that an omental pedicle flap is effective in the treatment of radio-necrosis of the chest wall and also stresses the importance of judging the extent of debridement of radio-necrotic tissue. (author)

Use of omental pedicle flap for radiation induced chest wall ulcer. A case report

Energy Technology Data Exchange (ETDEWEB)

Takamori, Shinzo; Hayashi, Akihiro; Nagamatsu, Yoshinori; Tsushimi, Mutsuo; Ono, Hirofumi; Ohtsuka, Shoji [Kurume Univ., Fukuoka (Japan). School of Medicine

1995-12-01

A 79-year-old female with breast carcinoma undergoing a classical Halsted radical mastectomy followed by irradiation (total; 180 Gy) 20 years before developed a left anterior chest wall ulcer. The ulcer was 10.0 x 8.0 cm in size with osteolysis of 3rd, 4th and 5th ribs, exposed pericardium, and parietal pleura with a pleuro-cutaneous fistula. After thorough debridement, an omental pedicle flap was transposed onto the chest wall defect and subsequently covered using a split-skin graft. The omental pedicle flap was 90% effective in covering the pericardial defect and resulted in a complete closure of the pleuro-cutaneous fistula. This report emphasises that an omental pedicle flap is effective in the treatment of radio-necrosis of the chest wall and also stresses the importance of judging the extent of debridement of radio-necrotic tissue. (author).

Effectiveness of the Thoracic Pedicle Screw Placement Using the Virtual Surgical Training System: A Cadaver Study.

Science.gov (United States)

Hou, Yang; Lin, Yanping; Shi, Jiangang; Chen, Huajiang; Yuan, Wen

2018-03-14

The virtual simulation surgery has initially exhibited its promising potentials in neurosurgery training. To evaluate effectiveness of the Virtual Surgical Training System (VSTS) on novice residents placing thoracic pedicle screws in a cadaver study. A total of 10 inexperienced residents participated in this study and were randomly assigned to 2 groups. The group using VSTS to learn thoracic pedicle screw fixation was the simulation training (ST) group and the group receiving an introductory teaching session was the control group. Ten fresh adult spine specimens including 6 males and 4 females with a mean age of 58.5 yr (range: 33-72) were collected and randomly allocated to the 2 groups. After exposing anatomic structures of thoracic spine, the bilateral pedicle screw placement of T6-T12 was performed on each cadaver specimen. The postoperative computed tomography scan was performed on each spine specimen, and experienced observers independently reviewed the placement of the pedicle screws to assess the incidence of pedicle breach. The screw penetration rates of the ST group (7.14%) was significantly lower in comparison to the control group (30%, P < .05). Statistically significant difference in acceptable rates of screws also occurred between the ST (100%) and control (92.86%) group (P < .05). In addition, the average screw penetration distance in control group (2.37 mm ± 0.23 mm) was significantly greater than ST group (1.23 mm ± 0.56 mm, P < .05). The virtual reality surgical training of thoracic pedicle screw instrumentation effectively improves surgical performance of novice residents compared to those with traditional teaching method, and can help new beginners to master the surgical technique within shortest period of time.

Estudo de acurácia em cirurgia assistida por navegação na revisão cirúrgica de deformidade vertebral Estudio de la precisión en cirugía asistida por navegación en la reoperación de deformidad espinal Study of the accuracy of navigation-assisted surgery in the surgical revision of spinal deformity

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Chárbel Jacob Junior

2011-01-01

segunda cirugía. En los 5 pacientes sometidos al reabordaje quirúrgico se procedió a instrumentación posterior con auxilio de la navegación. Fueron 84 tornillos pediculares implantados, siendo que 33 de éstos fueron asistidos por computación. La navegación fue empleada en los niveles de la deformidad vertebral en donde la anatomía se presentaba alterada impidiendo el uso correcto de los parámetros anatómicos para inserción de tornillos pediculares. En los demás niveles en donde era posible la correcta identificación de esos parámetros anatómicos se utilizó la técnica estándar. La TC postoperatoria fue realizada para medición del posicionamiento de los tornillos pediculares. Evaluamos los resultados obtenidos en el posicionamiento con y sin el uso de la navegación. El tiempo de fluoroscopía y el tiempo de la cirugía también fueron comparados con la regla áurea de la literatura. RESULTADOS: De los 33 tornillos implantados con navegación se observó una precisión de 94%, con una tasa de violación pedicular del 6%. CONCLUSIONES: El uso de la navegación es importante en la reoperación de las deformidades vertebrales con anatomía alterada, influenciando en el buen resultado de la cirugía.OBJECTIVE: To evaluate the benefits of computer-assisted spine surgery in re-operations due to vertebral deformities, and verify method accuracy. METHOD: A total of five patients with vertebral deformities who had complications during prior surgery were re-operated. These patients underwent a specific Computer Tomography scan with 2mm cuts of the spine before the second surgery. In the five patients who underwent re-operation, posterior instrumentation with the aid of computer-assisted spine surgery was performed. 84 pedicle screws were implanted, and in 33 of these computer-assisted surgeries were used. The computer-assisted surgery was used at the levels of spinal deformity where anatomy was altered making correct use of anatomical parameters for insertion of

Age-Specific Patient Navigation Preferences Among Adolescents and Young Adults with Cancer.

Science.gov (United States)

Pannier, Samantha T; Warner, Echo L; Fowler, Brynn; Fair, Douglas; Salmon, Sara K; Kirchhoff, Anne C

2017-11-23

Patient navigation is increasingly being directed at adolescent and young adult (AYA) patients. This study provides a novel description of differences in AYA cancer patients' preferences for navigation services by developmental age at diagnosis. Eligible patients were diagnosed with cancer between ages 15 and 39 and had completed at least 1 month of treatment. Between October 2015 and January 2016, patients completed semi-structured interviews about navigation preferences. Summary statistics of demographic and cancer characteristics were generated. Differences in patient navigation preferences were examined through qualitative analyses by developmental age at diagnosis. AYAs were interviewed (adolescents 15-18 years N = 8; emerging adults 19-25 years N = 8; young adults 26-39 years N = 23). On average, participants were 4.5 years from diagnosis. All age groups were interested in face-to-face connection with a navigator and using multiple communication platforms (phone, text, email) to follow-up. Three of the most frequently cited needs were insurance, finances, and information. AYAs differed in support, healthcare, and resource preferences by developmental age; only adolescents preferred educational support. While all groups preferred financial and family support, the specific type of assistance (medical versus living expenses, partner/spouse, child, or parental assistance) varied by age group. AYAs with cancer have different preferences for patient navigation by developmental age at diagnosis. AYAs are not a one-size-fits-all population, and navigation programs can better assist AYAs when services are targeted to appropriate developmental ages. Future research should examine fertility and navigation preferences by time since diagnosis. While some navigation needs to span the AYA age range, other needs are specific to developmental age.

Congenitally absent thoracic pedicle in a child with rhabdomyosarcoma

Energy Technology Data Exchange (ETDEWEB)

Kaufman, R A; Poznanski, A K; Hensinger, R N

1980-04-01

A case of congenital absence of a thoracic pedicle is reported in a 9 year old boy with embryonal rhabdomyosarcoma of the eyelid. In this clinical setting a surgical exploration was necessary in order to differentiate a developmental anomaly from an acquired metastatic deposit.

Post-traumatic arteriovenous fistula of the hepatic pedicle.

Science.gov (United States)

Ibn Majdoub Hassani, K; Mohsine, R; Belkouchi, A; Bensaid, Y

2010-10-01

Hepatico-portal fistula (HPF) is a rare condition, most often of post-traumatic or iatrogenic origin and occasionally secondary to a ruptured aneurysm of the hepatic artery into the portal vein. HPF in extrahepatic locations often results in portal hypertension (PHT). While Doppler ultrasound, CT angiography, and magnetic resonance angiography are usually demonstrative, arteriography remains indispensable to clarify the exact anatomical configuration. In the treatment of these arteriovenous (AV) fistulas, open surgical approaches have increasingly given way to radiological embolization techniques, especially in intrahepatic locations, but surgery remains indicated for AV fistulas of the hepatic pedicle where maintenance of hepatic arterial flow is a priority of treatment. We report a patient who had an AV fistula of the hepatic pedicle with resultant PHT presenting 5 years after open abdominal trauma. Treatment was surgical; the immediate and long-term postoperative course was uneventful with regression of PHT. Through analysis of this case and a review of the literature, we discuss the clinical, paraclinical, therapeutic, and prognostic features of this lesion. Copyright © 2010. Published by Elsevier Masson SAS.

Navigating ECA-Zones

DEFF Research Database (Denmark)

Hansen, Carsten Ørts; Grønsedt, Peter; Hendriksen, Christian

This report examines the effect that ECA-zone regulation has on the optimal vessel fuel strategies for compliance. The findings of this report are trifold, and this report is coupled with a calculation tool which is released to assist ship-owners in the ECA decision making. The first key insight...... much time their operated vessels navigate the ECA in the future....

[Cost analysis for navigation in knee endoprosthetics].

Science.gov (United States)

Cerha, O; Kirschner, S; Günther, K-P; Lützner, J

2009-12-01

Total knee arthroplasty (TKA) is one of the most frequent procedures in orthopaedic surgery. The outcome depends on a range of factors including alignment of the leg and the positioning of the implant in addition to patient-associated factors. Computer-assisted navigation systems can improve the restoration of a neutral leg alignment. This procedure has been established especially in Europe and North America. The additional expenses are not reimbursed in the German DRG system (Diagnosis Related Groups). In the present study a cost analysis of computer-assisted TKA compared to the conventional technique was performed. The acquisition expenses of various navigation systems (5 and 10 year depreciation), annual costs for maintenance and software updates as well as the accompanying costs per operation (consumables, additional operating time) were considered. The additional operating time was determined on the basis of a meta-analysis according to the current literature. Situations with 25, 50, 100, 200 and 500 computer-assisted TKAs per year were simulated. The amount of the incremental costs of the computer-assisted TKA depends mainly on the annual volume and the additional operating time. A relevant decrease of the incremental costs was detected between 50 and 100 procedures per year. In a model with 100 computer-assisted TKAs per year an additional operating time of 14 mins and a 10 year depreciation of the investment costs, the incremental expenses amount to 300-395 depending on the navigation system. Computer-assisted TKA is associated with additional costs. From an economical point of view an amount of more than 50 procedures per year appears to be favourable. The cost-effectiveness could be estimated if long-term results will show a reduction of revisions or a better clinical outcome.

Enabling Autonomous Navigation for Affordable Scooters

Directory of Open Access Journals (Sweden)

Kaikai Liu

2018-06-01

Full Text Available Despite the technical success of existing assistive technologies, for example, electric wheelchairs and scooters, they are still far from effective enough in helping those in need navigate to their destinations in a hassle-free manner. In this paper, we propose to improve the safety and autonomy of navigation by designing a cutting-edge autonomous scooter, thus allowing people with mobility challenges to ambulate independently and safely in possibly unfamiliar surroundings. We focus on indoor navigation scenarios for the autonomous scooter where the current location, maps, and nearby obstacles are unknown. To achieve semi-LiDAR functionality, we leverage the gyros-based pose data to compensate the laser motion in real time and create synthetic mapping of simple environments with regular shapes and deep hallways. Laser range finders are suitable for long ranges with limited resolution. Stereo vision, on the other hand, provides 3D structural data of nearby complex objects. To achieve simultaneous fine-grained resolution and long range coverage in the mapping of cluttered and complex environments, we dynamically fuse the measurements from the stereo vision camera system, the synthetic laser scanner, and the LiDAR. We propose solutions to self-correct errors in data fusion and create a hybrid map to assist the scooter in achieving collision-free navigation in an indoor environment.

Postero-Inferior Pedicle Surgical Technique for the Treatment of Grade III Gynecomastia.

Science.gov (United States)

Thiénot, Sophie; Bertheuil, Nicolas; Carloni, Raphaël; Méal, Cécile; Aillet, Sylvie; Herlin, Christian; Watier, Eric

2017-06-01

Surgical treatment of Grade III gynecomastia generally utilizes mastectomy techniques and free transplantation of the nipple-areola complex. Moreover, with rising obesity rates and the development of bariatric surgery, an increasing demand for correctional surgery for pseudogynecomastia has been observed, which is comparable to Grade III gynecomastia in terms of its surgical management. Here, we describe an innovative technique to deal with these new demands: fascio-cutaneous flap by postero-inferior pedicle. All patients in the Department of Plastic Surgery from our University Hospital suffering from Grade III gynecomastia or pseudogynecomastia underwent surgery via the postero-inferior pedicle flap technique. Briefly, we performed extensive liposuction of the infero-internal and infero-external mammary quadrants followed by liposuction of the deep tissues of the superior quadrants, except in the area of the pedicle. After removing the skin just above the dermis of the inferior quadrants and performing de-epithelialization of the postero-inferior pedicle flap, the thoracic flap was lowered and the areola transposed. Nine patients underwent surgery between March 2015 and March 2016, and their results were collected prospectively. The mean patient age was 46.6 years, the mean weight was 94.2 kg, and the mean body mass index was 30.8 kg/m 2 . In addition, the mean operative time was 132 min, the mean liposuction volume was 633 mL, the excised weight was 586 g, and the mean hospitalization and drainage durations were 3.8 days. No major complications occurred, no re-intervention was required, and no recurrence was found. We report a new operative technique using a postero-inferior pedicle. Its main advantage is preservation of neurovascular function, which makes this a promising technique for patients who wish to maintain nipple sensitivity. This surgery is reliable and reproducible. We recommend it as the first line treatment for Grade III gynecomastia because

Minimally invasive mini open split-muscular percutaneous pedicle screw fixation of the thoracolumbar spine

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Murat Ulutaş

2015-03-01

Full Text Available We prospectively assessed the feasibility and safety of a new percutaneous pedicle screw (PPS fixation technique for instrumentation of the thoracic and lumbar spine in this study. All patients were operated in the prone position under general anesthesia. A 6 to 8 cm midline skin incision was made and wide sub-cutaneous dissection was performed. The paravertebral muscles were first dissected subperiosteally into the midline incision of the fascia for lumbar microdiscectomy with transforaminal lumbar interbody fusion cage implantation. After the secondary paramedian incisions on the fascia, the PPSs were inserted via cleavage of the multifidus muscles directly into the pedicles under fluoroscopy visualization. A total of 35 patients underwent surgery with this new surgical technique. The control group for operative time, blood loss and analgesic usage consisted of 35 randomly selected cases from our department. The control group underwent surgery via conventional pedicle screw instrumentation with paramedian fusion. All patients in the minimal invasive surgery series were ambulatory with minimal pain on the first postoperative day. The operation time and blood loss and the postoperative analgesic consumption were significantly less with this new technique. In conclusion, the minimal invasive mini open split-muscular percutaneous pedicle screw fixation technique is safe and feasible. It can be performed via a short midline skin incision and can also be combined with interbody fusion, causing minimal pain without severe muscle damage.

Lower abdominal wall reconstructions with pedicled rectus femoris flaps

International Nuclear Information System (INIS)

Arashiro, Ken; Nishizeki, Osamu; Ishida, Kunihiro

2003-01-01

During the past 10 years, seven pedicled rectus femoris muscle or musculocutaneous flaps were used to repair lower abdominal defects; three recalcitrant incisional hernias with previous radiotherapy, two long-standing wound infections after synthetic mesh reconstruction, one posttraumatic wall defect and one metastatic tumor. There were two flap complications, one skin paddle necrosis and one wound infection. There was no significant disability of the donor limb encountered. During the two-year and seven month average follow-up, there was no recurrence of the problems except for one minor fascial dehiscence in the patient with metastatic abdominal wall tumor. Easy approach, rapid harvest, relatively large and reliable overlying fascia lata, a single dominant neurovascular pedicle, easy primary closure of the donor site, and minimal donor site morbidity all make the rectus femoris flap a good alternative flap for lower abdominal wall reconstruction. It is especially useful in a condition where synthetic mesh would be unsuitable for defects with infection or recurrent incisional hernia after radiotherapy. (author)

Towards cybernetic surgery: robotic and augmented reality-assisted liver segmentectomy.

Science.gov (United States)

Pessaux, Patrick; Diana, Michele; Soler, Luc; Piardi, Tullio; Mutter, Didier; Marescaux, Jacques

2015-04-01

Augmented reality (AR) in surgery consists in the fusion of synthetic computer-generated images (3D virtual model) obtained from medical imaging preoperative workup and real-time patient images in order to visualize unapparent anatomical details. The 3D model could be used for a preoperative planning of the procedure. The potential of AR navigation as a tool to improve safety of the surgical dissection is outlined for robotic hepatectomy. Three patients underwent a fully robotic and AR-assisted hepatic segmentectomy. The 3D virtual anatomical model was obtained using a thoracoabdominal CT scan with a customary software (VR-RENDER®, IRCAD). The model was then processed using a VR-RENDER® plug-in application, the Virtual Surgical Planning (VSP®, IRCAD), to delineate surgical resection planes including the elective ligature of vascular structures. Deformations associated with pneumoperitoneum were also simulated. The virtual model was superimposed to the operative field. A computer scientist manually registered virtual and real images using a video mixer (MX 70; Panasonic, Secaucus, NJ) in real time. Two totally robotic AR segmentectomy V and one segmentectomy VI were performed. AR allowed for the precise and safe recognition of all major vascular structures during the procedure. Total time required to obtain AR was 8 min (range 6-10 min). Each registration (alignment of the vascular anatomy) required a few seconds. Hepatic pedicle clamping was never performed. At the end of the procedure, the remnant liver was correctly vascularized. Resection margins were negative in all cases. The postoperative period was uneventful without perioperative transfusion. AR is a valuable navigation tool which may enhance the ability to achieve safe surgical resection during robotic hepatectomy.

Virtual surgery simulation versus traditional approaches in training of residents in cervical pedicle screw placement.

Science.gov (United States)

Hou, Yang; Shi, Jiangang; Lin, Yanping; Chen, Huajiang; Yuan, Wen

2018-06-01

The cervical screw placement is one of the most difficult procedures in spine surgery, which often needs a long period of repeated practices and could cause screw placement-related complications. We performed this cadaver study to investigate the effectiveness of virtual surgical training system (VSTS) on cervical pedicle screw instrumentation for residents. A total of ten novice residents were randomly assigned to two groups: the simulation training (ST) group (n = 5) and control group (n = 5). The ST group received a surgical training of cervical pedicle screw placement on VSTS and the control group was given an introductory teaching session before cadaver test. Ten fresh adult spine specimens including 6 males and 4 females were collected, and were randomly allocated to the two groups. The bilateral C3-C6 pedicle screw instrumentation was performed in the specimens of the two groups, respectively. After instrumentation, screw positions of the two groups were evaluated by image examinations. There was significantly statistical difference in screw penetration rates between the ST (10%) and control group (62.5%, P VSTS as an advanced training tool exhibited promising effects on improving performance of novice residents in cervical pedicle screw placement compared with the traditional teaching methods.

Aids to Navigation for US waters, including territories, as of April 2015

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Structures intended to assist a navigator to determine position or safe course, or to warn of dangers or obstructions to navigation. This dataset includes lights,...

Surgical reconstruction with pedicle flap of advance after excision of facial melanoma in a dog - Case report

Directory of Open Access Journals (Sweden)

Bruna Bristot Colombo

2016-06-01

Full Text Available ABSTRACT. Colombo B.B., Kuci C.C., Gehrcke M.I., de Souza L.P., Colodel M.M., Gerber J., Salbego F.Z., de Moraes A.N. & Oleskovicz N. [Surgical reconstruction with pedicle flap of advance after excision of facial melanoma in a dog - Case report.] Reconstrução cirúrgica com retalho pediculado de avanço após exérese de melanoma cutâneo facial em um cão - Relato de caso. Revista Brasileira de Medicina Veterinária, 38(2:128-132, 2016. Programa de Pós- -Graduação em Ciência Animal, Universidade do Estado de Santa Catarina, Av. Luís de Camões, 2090, Conta Dinheiro, Lages, SC 88520-000, Brasil. E-mail: brucolombo@hotmail.com The reconstructive surgery has been growing in veterinary medicine, whether in reconstruction tissue caused by trauma or even when there is an extensive tumor resection. This report aims to discuss about a female dog, assisted at the Teaching Hospital of an Educational Institution, which had an ulcerated nodule in the lateral portion of nasal flow plan, with suggestive diagnosis of malignant melanoma, concluded through cytology and referred for surgery. After resection of the tumor, the incision of skin and subcutaneous divulsion for production pedicle flap of advance. After surgery, it was applied with a padded bandage and gauze sheath on the face of the animal. During both the post-operative immediate period and in the following days the retail tissue showed rosy and healthy, with no sign of necrosis or dehiscence. The animal was observed until the day 30 after surgery, where there was local hair growth and good aesthetic appearance, which leads to the conclusion that the pedicle flap advance was an appropriate choice in this case, solving the matter about the animal’s health and looking from the owner’s point of view.

Vision Assisted Laser Scanner Navigation for Autonomous Robots

DEFF Research Database (Denmark)

Andersen, Jens Christian; Andersen, Nils Axel; Ravn, Ole

2008-01-01

This paper describes a navigation method based on road detection using both a laser scanner and a vision sensor. The method is to classify the surface in front of the robot into traversable segments (road) and obstacles using the laser scanner, this classifies the area just in front of the robot ...

Probing and Tapping: Are We Inserting Pedicle Screws Correctly?

Science.gov (United States)

Prasad, Vishal; Mesfin, Addisu; Lee, Robert; Reigrut, Julie; Schmidt, John

2016-11-01

Although there are a significant number of research publications on the topic of bone morphology and the strength of bone, the clinical significance of a failed pedicle screw is often revision surgery and the potential for further postoperative complications; especially in elderly patients with osteoporotic bone. The purpose of this report is to quantify the mechanical strength of the foam-screw interface by assessing probe/pilot hole diameter and tap sizes using statistically relevant sample sizes under highly controlled test conditions. The study consisted of two experiments and used up to three different densities of reference-grade polyurethane foam (ASTM 1839), including 0.16, 0.24, and 0.32 g/cm 3 . All screws and rods were provided by K2M Inc. and screws were inserted to a depth of 25 mm. A series of pilot holes, 1.5, 2.2, 2.7, 3.2, 3.7, 4.2, 5.0, and 6.0 mm in diameter were drilled through the entire depth of the material. A 6.5 × 45-mm pedicle screw was inserted and axially pulled from the material (n = 720). A 3.0-mm pilot hole was drilled and tapped with: no tap, 3.5-, 4.5-, 5.5-, and 6.5-mm taps. A 6.5 × 45-mm pedicle screw was inserted and axially pulled from the material (n = 300). The size of the probe/pilot hole had a nonlinear, parabolic effect on pullout strength. This shape suggests an optimum-sized probe hole for a given size pedicle screw. Too large or too small of a probe hole causes a rapid falloff in pullout strength. The tap data demonstrated that not tapping and undertapping by two or three sizes did not significantly alter the pullout strength of the screws. The data showed an exponential falloff of pullout strength when as tap size increased to the diameter of the screw. In the current study, the data show that an ideal pilot hole size half the diameter of the screw is a starting point. Also, that if tapping was necessary, to use a tap two sizes smaller than the screw being implanted. A similar optimum pilot hole or tap size may be

A case of severe congenital kyphoscoliosis secondary to multiple bilateral thoracic pedicle aplasia

International Nuclear Information System (INIS)

Geoffray, Anne; Leloutre, Beatrice; Albertario, Marco; Bechard-Sevette, Nancy; Clement, Jean-Luc

2008-01-01

A 9-month-old boy with congenital kyphoscoliosis secondary to multiple bilateral thoracic pedicle aplasias is presented. This anomaly has rarely been described in the literature. Plain films showed absence of thoracic pedicles bilaterally from T2 to T9, which was better demonstrated on CT multiplanar and 3-D reformatted images. There were no neurological symptoms even though the deformity progressed rapidly. Congenital kyphosis or kyphoscoliosis is often related to spinal anomalies that are located on the anterior aspect of the vertebrae. However, posterior anomalies may also be responsible and should be recognized before neurological complications occur. (orig.)

Navigation and Robotics in Spinal Surgery: Where Are We Now?

Science.gov (United States)

Overley, Samuel C; Cho, Samuel K; Mehta, Ankit I; Arnold, Paul M

2017-03-01

Spine surgery has experienced much technological innovation over the past several decades. The field has seen advancements in operative techniques, implants and biologics, and equipment such as computer-assisted navigation and surgical robotics. With the arrival of real-time image guidance and navigation capabilities along with the computing ability to process and reconstruct these data into an interactive three-dimensional spinal "map", so too have the applications of surgical robotic technology. While spinal robotics and navigation represent promising potential for improving modern spinal surgery, it remains paramount to demonstrate its superiority as compared to traditional techniques prior to assimilation of its use amongst surgeons.The applications for intraoperative navigation and image-guided robotics have expanded to surgical resection of spinal column and intradural tumors, revision procedures on arthrodesed spines, and deformity cases with distorted anatomy. Additionally, these platforms may mitigate much of the harmful radiation exposure in minimally invasive surgery to which the patient, surgeon, and ancillary operating room staff are subjected.Spine surgery relies upon meticulous fine motor skills to manipulate neural elements and a steady hand while doing so, often exploiting small working corridors utilizing exposures that minimize collateral damage. Additionally, the procedures may be long and arduous, predisposing the surgeon to both mental and physical fatigue. In light of these characteristics, spine surgery may actually be an ideal candidate for the integration of navigation and robotic-assisted procedures.With this paper, we aim to critically evaluate the current literature and explore the options available for intraoperative navigation and robotic-assisted spine surgery. Copyright © 2016 by the Congress of Neurological Surgeons.

Impact of trained oncology financial navigators on patient out-of-pocket spending.

Science.gov (United States)

Yezefski, Todd; Steelquist, Jordan; Watabayashi, Kate; Sherman, Dan; Shankaran, Veena

2018-03-01

Patients with cancer often face financial hardships, including loss of productivity, high out-of-pocket (OOP) costs, depletion of savings, and bankruptcy. By providing financial guidance and assistance through specially trained navigators, hospitals and cancer care clinics may be able mitigate the financial burdens to patients and also minimize financial losses for the treating institutions. Financial navigators at 4 hospitals were trained through The NaVectis Group, an organization that provides training to healthcare staff to increase patient access to care and assist with OOP expenses. Data regarding financial assistance and hospital revenue were collected after instituting these programs. Amount and type of assistance (free medication, new insurance enrollment, premium/co-pay assistance) were determined annually for all qualifying patients at the participating hospitals. Of 11,186 new patients with cancer seen across the 4 participating hospitals between 2012 and 2016, 3572 (32%) qualified for financial assistance. They obtained $39 million in total financial assistance, averaging $3.5 million per year in the 11 years under observation. Patients saved an average of $33,265 annually on medication, $12,256 through enrollment in insurance plans, $35,294 with premium assistance, and $3076 with co-pay assistance. The 4 hospitals were able to avoid write-offs and save on charity care by an average of $2.1 million per year. Providing financial navigation training to staff at hospitals and cancer centers can significantly benefit patients through decreased OOP expenditures and also mitigate financial losses for healthcare institutions.

iPod touch-assisted instrumentation of the spine: a technical report.

Science.gov (United States)

Jost, Gregory F; Bisson, Erica F; Schmidt, Meic H

2013-12-01

Instrumentation of the spine depends on choosing the correct insertion angles to implant screws. Although modern image guidance facilitates precise instrumentation of the spine, the equipment is costly and availability is limited. Although most surgeons use lateral fluoroscopy to guide instrumentation in the sagittal plane, the lateromedial angulation is often chosen by estimation. To overcome the associated uncertainty, iPod touch-based applications for measuring angles can be used to assist with screw implantation. To evaluate the use of the iPod touch to adjust instruments to the optimal axial insertion angle for placement of pedicle screws in the lumbar spine. Twenty lumbar pedicle screws in 5 consecutive patients were implanted using the iPod touch. The lateromedial angulation was measured on preoperative images and reproduced in the operative field with the iPod touch. The instruments to implant the screws were aligned with the side of the iPod for screw insertion. Actual screw angles were remeasured on postoperative imaging. We collected demographic, clinical, and operative data for each patient. In 16 of 20 screws, the accuracy of implantation was within 3 degrees of the ideal trajectory. The 4 screws with an angle mismatch of 7 to 13 degrees were all implanted at the caudal end of the exposure, where maintaining the planned angulation was impeded by strong muscles pushing medially. iPod touch-assisted instrumentation of the spine is a very simple technique, which, in combination with a lateral fluoroscopy, may guide placement of pedicle screws in the lumbar spine.

Needle and catheter navigation using electromagnetic tracking for computer-assisted C-arm CT interventions

Science.gov (United States)

Nagel, Markus; Hoheisel, Martin; Petzold, Ralf; Kalender, Willi A.; Krause, Ulrich H. W.

2007-03-01

Integrated solutions for navigation systems with CT, MR or US systems become more and more popular for medical products. Such solutions improve the medical workflow, reduce hardware, space and costs requirements. The purpose of our project was to develop a new electromagnetic navigation system for interventional radiology which is integrated into C-arm CT systems. The application is focused on minimally invasive percutaneous interventions performed under local anaesthesia. Together with a vacuum-based patient immobilization device and newly developed navigation tools (needles, panels) we developed a safe and fully automatic navigation system. The radiologist can directly start with navigated interventions after loading images without any prior user interaction. The complete system is adapted to the requirements of the radiologist and to the clinical workflow. For evaluation of the navigation system we performed different phantom studies and achieved an average accuracy of better than 2.0 mm.

Determining navigability of terrain using point cloud data.

Science.gov (United States)

Cockrell, Stephanie; Lee, Gregory; Newman, Wyatt

2013-06-01

This paper presents an algorithm to identify features of the navigation surface in front of a wheeled robot. Recent advances in mobile robotics have brought about the development of smart wheelchairs to assist disabled people, allowing them to be more independent. These robots have a human occupant and operate in real environments where they must be able to detect hazards like holes, stairs, or obstacles. Furthermore, to ensure safe navigation, wheelchairs often need to locate and navigate on ramps. The algorithm is implemented on data from a Kinect and can effectively identify these features, increasing occupant safety and allowing for a smoother ride.

The use of pedicled prepucial skin flap urethroplasty for proximal ...

African Journals Online (AJOL)

The use of pedicled prepucial skin flap urethroplasty for proximal bulbomembraneous urethral stricture in children: an easy alternative to transpubic urethroplasty. Harshjeet S. Bal, Jujju J. Kurian and Sudipta Sen. Objective Pediatric urethral strictures are not uncommon, and a myriad of treatment options is available.

Posterior Surgery for Adolescent Idiopathic Scoliosis With Pedicle Screws and Ultrahigh-Molecular Weight Polyethylene Tape: Achieving the Ideal Thoracic Kyphosis.

Science.gov (United States)

Imagama, Shiro; Ito, Zenya; Wakao, Norimitsu; Ando, Kei; Hirano, Kenichi; Tauchi, Ryoji; Muramoto, Akio; Matsui, Hiroki; Matsumoto, Tomohiro; Sakai, Yoshihito; Katayama, Yoshito; Matsuyama, Yukihiro; Ishiguro, Naoki

2016-10-01

Prospective clinical case series. To describe our surgical procedure and results for posterior correction and fusion with a hybrid approach using pedicle screws, hooks, and ultrahigh-molecular weight polyethylene tape with direct vertebral rotation (DVR) (the PSTH-DVR procedure) for treatment of adolescent idiopathic scoliosis (AIS) with satisfactory correction in the coronal and sagittal planes. Introduction of segmental pedicle screws in posterior surgery for AIS has facilitated good correction and fusion. However, procedures using only pedicle screws have risks during screw insertion, higher costs, and decreased postoperative thoracic kyphosis. We have obtained good outcomes compared with segmental pedicle screw fixation in surgery for AIS using a relatively simple operative procedure (PSTH-DVR) that uses fewer pedicle screws. The subjects were 30 consecutive patients with AIS who underwent the PSTH-DVR procedure and were followed for a minimum of 2 years. Preoperative flexibility, preoperative and postoperative Cobb angles, correction rates, loss of correction, thoracic kyphotic angles (T5-T12), coronal balance, sagittal balance, and shoulder balance were measured on plain radiographs. Rib hump, operation time, estimated blood loss, spinal cord monitoring findings, complications, and scoliosis research society (SRS)-22 scores were also examined. The mean preoperative curve of 58.0 degrees (range, 40-96 degrees) was corrected to a mean of 9.9 degrees postoperatively, and the correction rate was 83.6%. Fusion was obtained in all patients without loss of correction. In 10 cases with preoperative kyphosis angles (T5-T12) correction of deformity with PSTH-DVR is equivalent to that of all-pedicle screw constructs. The procedure gives favorable correction, is advantageous for kyphosis compared with segmental screw fixation, and uses the minimum number of pedicle screws. Therefore, the PSTH-DVR procedure may be useful for treatment of idiopathic scoliosis.

Phalloplasty with an Innervated Island Pedicled Anterolateral Thigh Flap in a Female-to-Male Transsexual

OpenAIRE

Hasegawa, Kenjiro; Namba, Yuzaburo; Kimata, Yoshihiro

2013-01-01

Since 2001, we have been performing phalloplasty with a radial forearm free flap as the flap of first choice in female-to-male transsexuals (FTMTS). In the present case, a 22-year-old FTMTS with a negative Allen test, we achieved good results by performing phalloplasty with an innervated island pedicled anterolateral thigh flap using the "tube within a tube" technique, in which the penis and urethra are constructed with a single flap. While phalloplasty with an island-pedicled or free anterol...

MIS Single-position Lateral and Oblique Lateral Lumbar Interbody Fusion and Bilateral Pedicle Screw Fixation: Feasibility and Perioperative Results.

Science.gov (United States)

Blizzard, Daniel J; Thomas, J Alex

2018-03-15

Retrospective review of prospectively collected data of the first 72 consecutive patients treated with single-position one- or two-level lateral (LLIF) or oblique lateral interbody fusion (OLLIF) with bilateral percutaneous pedicle screw and rod fixation by a single spine surgeon. To evaluate the clinical feasibility, accuracy, and efficiency of a single-position technique for LLIF and OLLIF with bilateral pedicle screw and rod fixation. Minimally-invasive lateral interbody approaches are performed in the lateral decubitus position. Subsequent repositioning prone for bilateral pedicle screw and rod fixation requires significant time and resources and does not facilitate increased lumbar lordosis. The first 72 consecutive patients (300 screws) treated with single-position LLIF or OLLIF and bilateral pedicle screws by a single surgeon between December 2013 and August 2016 were included in the study. Screw accuracy and fusion were graded using computed tomography and several timing parameters were recorded including retractor, fluoroscopy, and screw placement time. Complications including reoperation, infection, and postoperative radicular pain and weakness were recorded. Average screw placement time was 5.9 min/screw (standard deviation, SD: 1.5 min; range: 3-9.5 min). Average total operative time (interbody cage and pedicle screw placement) was 87.9 minutes (SD: 25.1 min; range: 49-195 min). Average fluoroscopy time was 15.0 s/screw (SD: 4.7 s; range: 6-25 s). The pedicle screw breach rate was 5.1% with 10/13 breaches measured as < 2 mm in magnitude. Fusion rate at 6-months postoperative was 87.5%. Two (2.8%) patients underwent reoperation for malpositioned pedicle screws with subsequent resolution of symptoms. The single-position, all-lateral technique was found to be feasible with accuracy, fluoroscopy usage, and complication rates comparable with the published literature. This technique eliminates the time and staffing associated with

Additive-manufactured patient-specific titanium templates for thoracic pedicle screw placement: novel design with reduced contact area.

Science.gov (United States)

Takemoto, Mitsuru; Fujibayashi, Shunsuke; Ota, Eigo; Otsuki, Bungo; Kimura, Hiroaki; Sakamoto, Takeshi; Kawai, Toshiyuki; Futami, Tohru; Sasaki, Kiyoyuki; Matsushita, Tomiharu; Nakamura, Takashi; Neo, Masashi; Matsuda, Shuich

2016-06-01

Image-based navigational patient-specific templates (PSTs) for pedicle screw (PS) placement have been described. With recent advances in three-dimensional computer-aided designs and additive manufacturing technology, various PST designs have been reported, although the template designs were not optimized. We have developed a novel PST design that reduces the contact area without sacrificing stability. It avoids susceptibility to intervening soft tissue, template geometric inaccuracy, and difficulty during template fitting. Fourteen candidate locations on the posterior aspect of the vertebra were evaluated. Among them, locations that had high reproducibility on computed tomography (CT) images and facilitated accurate PS placement were selected for the final PST design. An additive manufacturing machine (EOSINT M270) fabricated the PSTs using commercially pure titanium powder. For the clinical study, 36 scoliosis patients and 4 patients with ossification of the posterior longitudinal ligament (OPLL) were treated with thoracic PSs using our newly developed PSTs. We intraoperatively and postoperatively evaluated the accuracy of the PS hole created by the PST. Based on the segmentation reproducibility and stability analyses, we selected seven small, round contact points for our PST: bilateral superior and inferior points on the transverse process base, bilateral inferior points on the laminar, and a superior point on the spinous process. Clinically, the success rates of PS placement using this PST design were 98.6 % (414/420) for scoliosis patients and 100 % (46/46) for OPLL patients. This study provides a useful design concept for the development and introduction of patient-specific navigational templates for placing PSs.

Transport Canada : navigable water protection technical paper on boating safety at dams

Energy Technology Data Exchange (ETDEWEB)

Putt, B [Transport Canada, Sarnia, ON (Canada); Di Censo, V M [Transport Canada, Ottawa, ON (Canada)

2009-07-01

The Navigable Waters Protection Act (NWPA) was designed to ensure a balance between public rights of navigation and the need to build bridges, dams, and other structures. This paper discussed an owner's guide to navigation safety around water control structures. Developed by Transport Canada, the guide was intended to help owners of water control structures address boating safety matters and assist owners in making applications under the NWPA. The guide was prepared to address amendments made to the NWPA in 2009 as well as to assist owners in identifying potential hazards and interactions by the boating public at water control structures. The guide included information related to signage; navigation aids; barriers and booms; warning alerts and alarms; portage and access around structures; and application requirements. It was concluded that the guide will also provide a summary of legislation that may affect owners of water control structures.

Pedicle Screw Fixation Study in Immature Porcine Spines to Improve Pullout Resistance during Animal Testing.

Directory of Open Access Journals (Sweden)

Sophie Le Cann

Full Text Available The porcine model is frequently used during development and validation of new spinal devices, because of its likeness to the human spine. These spinal devices are frequently composed of pedicle screws with a reputation for stable fixation but which can suffer pullouts during preclinical implantation on young animals, leading to high morbidity. With a view to identifying the best choices to optimize pedicle screw fixation in the porcine model, this study evaluates ex vivo the impact of weight (age of the animal, the level of the vertebrae (lumbar or thoracic and the type of screw anchorage (mono- or bi-cortical on pedicle screw pullouts. Among the 80 pig vertebrae (90- and 140-day-old tested in this study, the average screw pullout forces ranged between 419.9N and 1341.2N. In addition, statistical differences were found between test groups, pointing out the influence of the three parameters stated above. We found that the the more caudally the screws are positioned (lumbar level, the greater their pullout resistance is, moreover, screw stability increases with the age, and finally, the screws implanted with a mono-cortical anchorage sustained lower pullout forces than those implanted with a bi-cortical anchorage. We conclude that the best anchorage can be obtained with older animals, using a lumbar fixation and long screws traversing the vertebra and inducing bi-cortical anchorage. In very young animals, pedicle screw fixations need to be bi-cortical and more numerous to prevent pullout.

Pedicle Screw Fixation Study in Immature Porcine Spines to Improve Pullout Resistance during Animal Testing.

Science.gov (United States)

Le Cann, Sophie; Cachon, Thibaut; Viguier, Eric; Miladi, Lotfi; Odent, Thierry; Rossi, Jean-Marie; Chabrand, Patrick

2015-01-01

The porcine model is frequently used during development and validation of new spinal devices, because of its likeness to the human spine. These spinal devices are frequently composed of pedicle screws with a reputation for stable fixation but which can suffer pullouts during preclinical implantation on young animals, leading to high morbidity. With a view to identifying the best choices to optimize pedicle screw fixation in the porcine model, this study evaluates ex vivo the impact of weight (age) of the animal, the level of the vertebrae (lumbar or thoracic) and the type of screw anchorage (mono- or bi-cortical) on pedicle screw pullouts. Among the 80 pig vertebrae (90- and 140-day-old) tested in this study, the average screw pullout forces ranged between 419.9N and 1341.2N. In addition, statistical differences were found between test groups, pointing out the influence of the three parameters stated above. We found that the the more caudally the screws are positioned (lumbar level), the greater their pullout resistance is, moreover, screw stability increases with the age, and finally, the screws implanted with a mono-cortical anchorage sustained lower pullout forces than those implanted with a bi-cortical anchorage. We conclude that the best anchorage can be obtained with older animals, using a lumbar fixation and long screws traversing the vertebra and inducing bi-cortical anchorage. In very young animals, pedicle screw fixations need to be bi-cortical and more numerous to prevent pullout.

Stress analysis in a pedicle screw fixation system with flexible rods in the lumbar spine.

Science.gov (United States)

Kim, Kyungsoo; Park, Won Man; Kim, Yoon Hyuk; Lee, SuKyoung

2010-01-01

Breakage of screws has been one of the most common complications in spinal fixation systems. However, no studies have examined the breakage risk of pedicle screw fixation systems that use flexible rods, even though flexible rods are currently being used for dynamic stabilization. In this study, the risk of breakage of screws for the rods with various flexibilities in pedicle screw fixation systems is investigated by calculating the von Mises stress as a breakage risk factor using finite element analysis. Three-dimensional finite element models of the lumbar spine with posterior one-level spinal fixations at L4-L5 using four types of rod (a straight rod, a 4 mm spring rod, a 3 mm spring rod, and a 2 mm spring rod) were developed. The von Mises stresses in both the pedicle screws and the rods were analysed under flexion, extension, lateral bending, and torsion moments of 10 Nm with a follower load of 400 N. The maximum von Mises stress, which was concentrated on the neck region of the pedicle screw, decreased as the flexibility of the rod increased. However, the ratio of the maximum stress in the rod to the yield stress increased substantially when a highly flexible rod was used. Thus, the level of rod flexibility should be considered carefully when using flexible rods for dynamic stabilization because the intersegmental motion facilitated by the flexible rod results in rod breakage.

Fatigue life prediction of pedicle screw for spinal surgery

Czech Academy of Sciences Publication Activity Database

Major, Štěpán; Kocour, Vladimír; Cyrus, P.

2016-01-01

Roč. 10, č. 35 (2016), s. 379-388 ISSN 1971-8993. [European Conference on Fracture. ECF21. Catania, 20.06.2015-20.06.2015] Institutional support: RVO:68378297 Keywords : pedicle-screw * titan alloy * fatigue life * finite element analysis Subject RIV: JK - Corrosion ; Surface Treatment of Materials http://www.fracturae.com/index.php/fis/article/view/IGF-ESIS.35.43

Minimally Invasive Spinal Surgery with Intraoperative Image-Guided Navigation

Directory of Open Access Journals (Sweden)

Terrence T. Kim

2016-01-01

Full Text Available We present our perioperative minimally invasive spine surgery technique using intraoperative computed tomography image-guided navigation for the treatment of various lumbar spine pathologies. We present an illustrative case of a patient undergoing minimally invasive percutaneous posterior spinal fusion assisted by the O-arm system with navigation. We discuss the literature and the advantages of the technique over fluoroscopic imaging methods: lower occupational radiation exposure for operative room personnel, reduced need for postoperative imaging, and decreased revision rates. Most importantly, we demonstrate that use of intraoperative cone beam CT image-guided navigation has been reported to increase accuracy.

Requirements for e-Navigation Architectures

Directory of Open Access Journals (Sweden)

Axel Hahn

2016-12-01

Full Text Available Technology is changing the way of navigation. New technologies for communication and navigation can be found on virtually every vessel. System architectures define structure and cooperation of components and subsystems. IMO, IALA, costal authorities, technology provider and many more actually propose new architectures for e-Navigation. This paper looks at other transportation domains and technical as normative requirements for e-Navigation architectures. With the aim of identifying possible synergies in the research, development, certification and standardization, this paper sets out to compare requirements and approaches of these two domains with respect to safety and security aspects. Since from an autonomy perspective, the automotive domain has started earlier and therefore has achieved a higher degree of technical progress, we will start with an overview of the developments in this domain. After that, the paper discusses the requirements on automation and assistance systems in the maritime domain and gives an overview of the developments into this direction within the maritime domain. This then allows us to compare developments in both domains and to derive recommendations for further developments in the maritime domain at the end of this paper.

What is the Difference in Morphologic Features of the Thoracic Pedicle Between Patients With Adolescent Idiopathic Scoliosis and Healthy Subjects? A CT-based Case-control Study.

Science.gov (United States)

Gao, Bo; Gao, Wenjie; Chen, Chong; Wang, Qinghua; Lin, Shaochun; Xu, Caixia; Huang, Dongsheng; Su, Peiqiang

2017-11-01

Describing the morphologic features of the thoracic pedicle in patients with adolescent idiopathic scoliosis is necessary for placement of pedicle screws. Previous studies showed inadequate reliability owing to small sample size and heterogeneity of the patients surveyed. To use CT scans (1) to describe the morphologic features of 2718 thoracic pedicles from 60 female patients with Lenke Type 1 adolescent idiopathic scoliosis and 60 age-, sex-, and height-matched controls; and (2) to classify the pedicles in three types based on pedicle width and analyze the distribution of each type. A total of 2718 pedicles from 60 female patients with Lenke Type 1 adolescent idiopathic scoliosis and 60 matched female controls were analyzed via CT. All patients surveyed were diagnosed with adolescent idiopathic scoliosis, Lenke Type 1, at the First Affiliated Hospital of Sun Yat-sen University, and all underwent pedicle screw fixation between January 2008 and December 2013 with preoperative radiographs and CT images on file. We routinely obtained CT scans before these procedures; all patients who underwent surgery during that period had CT scans, and all were available for analysis here. Control subjects had CT scans for other clinical indications and had no abnormal findings of the spine. The control subjects were chosen to match patients in terms of age (15 ± 2.6 years versus 15 ± 2.6 years) and sex. Height of the two groups also was matched (154 ± 9 cm versus 155 ± 10 cm; mean difference, -1.06 cm; 95% CI, -1.24 to -0.81 cm; p adolescent idiopathic scoliosis (22%; 293 of 1322) compared with controls (13%; 178 of 1396) (odds ratio [OR] = 0.51; 95% CI, 0.42-0.63; p adolescent idiopathic scoliosis, they commonly occurred on the concave side 34% (228 of 661) and on the AV-SC region (32%; 43 of 136). Pedicle width on the concave side was narrower than pedicle width on the convex side and pedicle width in healthy control subjects. The apical vertebra in the structural curve was

CT provides precise size assessment of implanted titanium alloy pedicle screws.

Science.gov (United States)

Elliott, Michael J; Slakey, Joseph B

2014-05-01

After performing instrumented spinal fusion with pedicle screws, postoperative imaging using CT to assess screw position may be necessary. Stainless steel implants produce significant metal artifact on CT, and the degree of distortion is at least partially dependent on the cross-sectional area of the implanted device. If the same effect occurs with titanium alloy implants, ability to precisely measure proximity of screws to adjacent structures may be adversely affected as screw size increases. We therefore asked whether (1) CT provides precise measurements of true screw widths; and (2) precision degrades based on the size of the titanium implant imaged. CT scans performed on 20 patients after instrumented spinal fusion for scoliosis were reviewed. The sizes of 151 titanium alloy pedicle screws were measured and compared with known screw size. The amount of metal bloom artifact was determined for each of the four screw sizes. ANOVA with Tukey's post hoc test were performed to evaluate differences in scatter, and Spearman's rho coefficient was used to measure relationship between screw size and scatter. All screws measured larger than their known size, but even with larger 7-mm screws the size differential was less than 1 mm. The four different screw sizes produced scatter amounts that were different from each other (p titanium alloy pedicle screws produces minimal artifact, thus making this the preferred imaging modality to assess screw position after surgery. Although the amount of artifact increases with the volume of titanium present, the degree of distortion is minimal and is usually less than 1 mm.

Surgical navigation in urology: European perspective.

Science.gov (United States)

Rassweiler, Jens; Rassweiler, Marie-Claire; Müller, Michael; Kenngott, Hannes; Meinzer, Hans-Peter; Teber, Dogu

2014-01-01

Use of virtual reality to navigate open and endoscopic surgery has significantly evolved during the last decade. Current status of seven most interesting projects inside the European Association of Urology section of uro-technology is summarized with review of literature. Marker-based endoscopic tracking during laparoscopic radical prostatectomy using high-definition technology reduces positive margins. Marker-based endoscopic tracking during laparoscopic partial nephrectomy by mechanical overlay of three-dimensional-segmented virtual anatomy is helpful during planning of trocar placement and dissection of renal hilum. Marker-based, iPAD-assisted puncture of renal collecting system shows more benefit for trainees with reduction of radiation exposure. Three-dimensional laser-assisted puncture of renal collecting system using Uro-Dyna-CT realized in an ex-vivo model enables minimal radiation time. Electromagnetic tracking for puncture of renal collecting system using a sensor at the tip of ureteral catheter worked in an in-vivo model of porcine ureter and kidney. Attitude tracking for ultrasound-guided puncture of renal tumours by accelerometer reduces the puncture error from 4.7 to 1.8 mm. Feasibility of electromagnetic and optical tracking with the da Vinci telemanipulator was shown in vitro as well as using in-vivo model of oesophagectomy. Target registration error was 11.2 mm because of soft-tissue deformation. Intraoperative navigation is helpful during percutaneous puncture collecting system and biopsy of renal tumour using various tracking techniques. Early clinical studies demonstrate advantages of marker-based navigation during laparoscopic radical prostatectomy and partial nephrectomy. Combination of different tracking techniques may further improve this interesting addition to video-assisted surgery.

Satisfactory Short-Term Results of Navigation-Assisted Gap-Balancing Total Knee Arthroplasty Using Ultracongruent Insert.

Science.gov (United States)

Yoon, Jung-Ro; Yang, Jae-Hyuk

2018-03-01

The use of highly conforming ultracongruent (UC) polyethylene insert is bone-preserving and became a relatively common alternative to the conventional posterior stabilized total knee arthroplasty (TKA) design. The purpose of this study was to analyze the short-term clinical and radiologic results of UC insert TKA using the navigation-assisted gap-balancing technique. Two hundred thirty-three knees were operated with a mean follow-up period of 8.1 years (minimum of 5 years). Radiologic and clinical outcomes were assessed before operation and at latest follow-up using the Knee Society Score and Western Ontario and McMaster Universities Osteoarthritis Index score. For statistical analysis, paired sample t-test and analysis of variance were used. Significance was considered as P satisfactory short-term outcome. Strict gap-balancing technique using the offset-type-force-controlled-spreader-system aided in the satisfactory results. Copyright © 2017 Elsevier Inc. All rights reserved.

Misdiagnosing absent pedicle of cervical spine in the acute trauma setting

Directory of Open Access Journals (Sweden)

Fahad H. Abduljabbar

2015-09-01

Full Text Available Congenital absence of cervical spine pedicle can be easily misdiagnosed as facet dislocation on plain radiographs especially in the acute trauma setting. Additional imaging, including computed tomography (CT-scan with careful interpretation is required in order to not misdiagnose cervical posterior arch malformation with subsequent inappropriate management. A 39-year-old patient presented to the emergency unit of our university hospital after being trampled by a cow over her back and head followed by loss of consciousness, retrograde amnesia and neck pain. Her initial cervical CT-scan showed possible C5-C6 dislocation, then, it became clear that her problem was a misdiagnosed congenital cervical abnormality. Patient was treated symptomatically without consequences. The congenital absence of a cervical pedicle is a very unusual condition that is easily misdiagnosed. Diagnosis can be accurately confirmed with a CT-scan of the cervical spine. Symptomatic conservative treatment will result in resolution of the symptoms.

A great number of old vertebral fractures expressing instability are pedicle fractures. With the use of 64-line multi slice computerized tomography

International Nuclear Information System (INIS)

Kobayashi, Akihiko; Nishida, Kenki; Ogawa, Koichi; Takahashi, Yuichi; Nakahara, Masayuki; Hijikata, Yasukazu

2008-01-01

We examined old vertebral fractures expressing instability with the use of 64-line CT. From April 2006 to December 2006, CT photographic images of 15 unstable fractures were examined in detail. We confirmed gas or liquid in all vertebral bodies. In 5 cases (33%), vertebral body protruding into the canal was observed. Four cases (23%) had other vertebral fractures. In addition, 12 pedicle fractures (73%) were seen. We confirmed many pedicle fractures in vertebral fractures expressing instability. These results suggest that pedicle fracture is a risk factor for back pain associated with vertebral fracture. (author)

Real-time Pedestrian Crossing Recognition for Assistive Outdoor Navigation.

Science.gov (United States)

Fontanesi, Simone; Frigerio, Alessandro; Fanucci, Luca; Li, William

2015-01-01

Navigation in urban environments can be difficult for people who are blind or visually impaired. In this project, we present a system and algorithms for recognizing pedestrian crossings in outdoor environments. Our goal is to provide navigation cues for crossing the street and reaching an island or sidewalk safely. Using a state-of-the-art Multisense S7S sensor, we collected 3D pointcloud data for real-time detection of pedestrian crossing and generation of directional guidance. We demonstrate improvements to a baseline, monocular-camera-based system by integrating 3D spatial prior information extracted from the pointcloud. Our system's parameters can be set to the actual dimensions of real-world settings, which enables robustness of occlusion and perspective transformation. The system works especially well in non-occlusion situations, and is reasonably accurate under different kind of conditions. As well, our large dataset of pedestrian crossings, organized by different types and situations of pedestrian crossings in order to reflect real-word environments, is publicly available in a commonly used format (ROS bagfiles) for further research.

Interactive navigation-guided ophthalmic plastic surgery: navigation enabling of telescopes and their use in endoscopic lacrimal surgeries

Directory of Open Access Journals (Sweden)

Ali MJ

2016-11-01

Full Text Available Mohammad Javed Ali,1 Swati Singh,1 Milind N Naik,1 Swathi Kaliki,2 Tarjani Vivek Dave1 1The Institute of Dacryology, 2The Operation Eyesight Universal Institute for Eye Cancer, L.V. Prasad Eye Institute, Hyderabad, India Purpose: The aims of this study were to report the preliminary experience of using telescopes, which were enabled for navigation guidance, and their utility in complex endoscopic lacrimal surgeries. Methods: Navigation enabling of the telescope was achieved by using the AxiEM™ malleable neuronavigation shunt stylet. Image-guided dacryolocalization was performed in five patients using the intraoperative image-guided StealthStation™ system in the electromagnetic mode. The “look ahead” protocol software was used to assist the surgeon in assessing the intraoperative geometric location of the endoscope and what lies ahead in real time. All patients underwent navigation-guided powered endoscopic dacryocystorhinostomy. The utility of uninterrupted navigation guidance throughout the surgery with the endoscope as the navigating tool was noted. Results: Intraoperative geometric localization of the lacrimal sac and the nasolacrimal duct could be easily deciphered. Constant orientation of the lacrimal drainage system and the peri-lacrimal anatomy was possible without the need for repeated point localizations throughout the surgery. The “look ahead” features could accurately alert the surgeon of anatomical structures that exists at 5, 10 and 15 mm in front of the endoscope. Good securing of the shunt stylet with the telescope was found to be essential for constant and accurate navigation. Conclusion: Navigation-enabled endoscopes provide the surgeon with the advantage of sustained stereotactic anatomical awareness at all times during the surgery. Keywords: telescope, endoscope, image guidance, navigation, lacrimal surgery, powered endoscopic DCR

In vitro validation of a novel mechanical model for testing the anchorage capacity of pedicle screws using physiological load application.

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Liebsch, Christian; Zimmermann, Julia; Graf, Nicolas; Schilling, Christoph; Wilke, Hans-Joachim; Kienle, Annette

2018-01-01

Biomechanical in vitro tests analysing screw loosening often include high standard deviations caused by high variabilities in bone mineral density and pedicle geometry, whereas standardized mechanical models made of PU foam often do not integrate anatomical or physiological boundary conditions. The purpose of this study was to develop a most realistic mechanical model for the standardized and reproducible testing of pedicle screws regarding the resistance against screw loosening and the holding force as well as to validate this model by in vitro experiments. The novel mechanical testing model represents all anatomical structures of a human vertebra and is consisting of PU foam to simulate cancellous bone, as well as a novel pedicle model made of short carbon fibre filled epoxy. Six monoaxial cannulated pedicle screws (Ø6.5 × 45mm) were tested using the mechanical testing model as well as human vertebra specimens by applying complex physiological cyclic loading (shear, tension, and bending; 5Hz testing frequency; sinusoidal pulsating forces) in a dynamic materials testing machine with stepwise increasing load after each 50.000 cycles (100.0N shear force + 20.0N per step, 51.0N tension force + 10.2N per step, 4.2Nm bending moment + 0.8Nm per step) until screw loosening was detected. The pedicle screw head was fixed on a firmly clamped rod while the load was applied in the vertebral body. For the in vitro experiments, six human lumbar vertebrae (L1-3, BMD 75.4 ± 4.0mg/cc HA, pedicle width 9.8 ± 0.6mm) were tested after implanting pedicle screws under X-ray control. Relative motions of pedicle screw, specimen fixture, and rod fixture were detected using an optical motion tracking system. Translational motions of the mechanical testing model experiments in the point of load introduction (0.9-2.2mm at 240N shear force) were reproducible within the variation range of the in vitro experiments (0.6-3.5mm at 240N shear force). Screw loosening occurred continuously in

Pilot Feasibility Study of an Oncology Financial Navigation Program.

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Shankaran, Veena; Leahy, Tony; Steelquist, Jordan; Watabayashi, Kate; Linden, Hannah; Ramsey, Scott; Schwartz, Naomi; Kreizenbeck, Karma; Nelson, Judy; Balch, Alan; Singleton, Erin; Gallagher, Kathleen; Overstreet, Karen

2018-02-01

Few studies have reported on interventions to alleviate financial toxicity in patients with cancer. We developed a financial navigation program in collaboration with our partners, Consumer Education and Training Services (CENTS) and Patient Advocate Foundation (PAF), to improve patient knowledge about treatment costs, provide financial counseling, and to help manage out-of-pocket expenses. We conducted a pilot study to assess the feasibility and impact of this program. Patients with cancer received a financial education course followed by monthly contact with a CENTS financial counselor and a PAF case manager for 6 months. We measured program adherence, self-reported financial burden and anxiety, program satisfaction, and type of assistance provided. Thirty-four patients (median age, 60.5 years) were consented (85% white and 50% commercially insured). Debt, income declines, and loans were reported by 55%, 55%, and 30% of patients, respectively. CENTS counselors assisted most often with budgeting, retirement planning, and medical bill questions. PAF case managers assisted with applications for appropriate insurance coverage, cost of living issues (eg, housing, transportation), and disability applications. High financial burden and anxiety about costs (4 or 5 on a Likert scale) were reported at baseline by 37% and 47% of patients, respectively. Anxiety about costs decreased over time in 33% of patients, whereas self-reported financial burden did not substantially change. Implementing an oncology financial navigation program is feasible, provides concrete assistance in navigating the cost of care, and mitigates anxiety about costs in a subset of patients. Future work will focus on measuring the program's impact on financial and clinical outcomes.

Comparison of the Pullout Strength of Different Pedicle Screw Designs and Augmentation Techniques in an Osteoporotic Bone Model.

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Kiyak, Gorkem; Balikci, Tevfik; Heydar, Ahmed Majid; Bezer, Murat

2018-02-01

Mechanical study. To compare the pullout strength of different screw designs and augmentation techniques in an osteoporotic bone model. Adequate bone screw pullout strength is a common problem among osteoporotic patients. Various screw designs and augmentation techniques have been developed to improve the biomechanical characteristics of the bone-screw interface. Polyurethane blocks were used to mimic human osteoporotic cancellous bone, and six different screw designs were tested. Five standard and expandable screws without augmentation, eight expandable screws with polymethylmethacrylate (PMMA) or calcium phosphate augmentation, and distal cannulated screws with PMMA and calcium phosphate augmentation were tested. Mechanical tests were performed on 10 unused new screws of each group. Screws with or without augmentation were inserted in a block that was held in a fixture frame, and a longitudinal extraction force was applied to the screw head at a loading rate of 5 mm/min. Maximum load was recorded in a load displacement curve. The peak pullout force of all tested screws with or without augmentation was significantly greater than that of the standard pedicle screw. The greatest pullout force was observed with 40-mm expandable pedicle screws with four fins and PMMA augmentation. Augmented distal cannulated screws did not have a greater peak pullout force than nonaugmented expandable screws. PMMA augmentation provided a greater peak pullout force than calcium phosphate augmentation. Expandable pedicle screws had greater peak pullout forces than standard pedicle screws and had the advantage of augmentation with either PMMA or calcium phosphate cement. Although calcium phosphate cement is biodegradable, osteoconductive, and nonexothermic, PMMA provided a significantly greater peak pullout force. PMMA-augmented expandable 40-mm four-fin pedicle screws had the greatest peak pullout force.

Load-bearing evaluation of spinal posterior column by measuring surface strain from lumbar pedicles. An in vitro study.

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Sun, Peidong; Zhao, Weidong; Bi, Zhenyu; Wu, Changfu; Ouyang, Jun

2012-01-01

An understanding of the load transfer within spinal posterior column of lumbar spine is necessary to determine the influence of mechanical factors on potential mechanisms of the motion-sparing implant such as artificial intervertebral disc and the dynamic spine stabilization systems. In this study, a new method has been developed for evaluating the load bearing of spinal posterior column by the surface strain of spinal pedicle response to the loading of spinal segment. Six cadaveric lumbar spine segments were biomechanically evaluated between levels L1 and L5 in intact condition and the strain gauges were pasted to an inferior surface of L2 pedicles. Multidirectional flexibility testing used the Panjabi testing protocol; pure moments for the intact condition with overall spinal motion and unconstrained intact moments of ±8 Nm were used for flexion-extension and lateral bending testing. High correlation coefficient (0.967-0.998) indicated a good agreement between the load of spinal segment and the surface strain of pedicle in all loading directions. Principal compressive strain could be observed in flexion direction and tensile strain in extension direction, respectively. In conclusion, the new method seems to be effective for evaluating posterior spinal column loads using pedicles' surface strain data collected during biomechanical testing of spine segments.

CT study of vertebral metastasis: re-realization of the diagnostic role of the vertebral pedicle sign

International Nuclear Information System (INIS)

Meng Quanfei; Jiang Bo; Chen Yingming; Zhang Chaohui

2000-01-01

Objective: To investigate the essence of the vertebral pedicle sign of vertebral metastasis on plain film, and to explore the useful CT signs for the diagnosis and differential diagnosis of this tumor. Methods: The CT scans of the spine obtained in 48 patients with vertebral metastases, 19 patients with vertebral tuberculosis, and 11 with vertebral myeloma, were analyzed. The CT findings were correlated with the abnormalities seen on plain films in 34 of the 48 patients (66 vertebrae involved) with vertebral metastasis. Results: 66 vertebrae were involved in the group of metastasis. Of the 28 vertebrae whose vertebral body were completely destroyed, 15 were seen bilateral pedicles destruction; Of the 22 vertebrae with lateral destruction of the body, 16 were noticed unilateral pedicle destruction which located posterior to the involved side of the body. Of the 62 micro-metastatic foci, 56 were scattered in the vertebral body. In the 19 para-spinal soft-tissue masses of vertebral tuberculosis, 5 were noticed calcifications and 12 with postcontrast rings enhancement. The rates of vertebral pedicle destruction of vertebral metastasis and myeloma were not statistically different (X 2 = 0.03, P > 0.50). The locations of destruction of vertebral body in vertebral metastasis and myeloma had no statistical difference (X 2 = 3.52, P > 0.10), but they differed from that in tuberculosis (X 2 = 39.32, P < 0.001). The distribution of lesions within the vertebrae of metastasis and tuberculosis was similar, but was quite different from myeloma. Conclusion: The vertebral metastasis initially occurs in the vertebral body. The vertebral pedicle sign on plain film of vertebral metastasis is the outcome of the posterior invasion of the tumor in the vertebral body, which is of no differential significance for vertebral metastasis and myeloma. Para-spinal soft tissue mass, location of destruction of vertebral body, and the distribution of lesions within the vertebrae may help

Cost-Utility Analysis of Pedicle Screw Removal After Successful Posterior Instrumented Fusion in Thoracolumbar Burst Fractures.

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Lee, Han-Dong; Jeon, Chang-Hoon; Chung, Nam-Su; Seo, Young-Wook

2017-08-01

A cost-utility analysis (CUA). The aim of this study was to determine the cost-effectiveness of pedicle screw removal after posterior fusion in thoracolumbar burst fractures. Pedicle screw instrumentation is a standard fixation method for unstable thoracolumbar burst fracture. However, removal of the pedicle screw after successful fusion remains controversial because the clinical benefits remain unclear. CUA can help clinicians make appropriate decisions about optimal health care for pedicle screw removal after successful fusion in thoracolumbar burst fractures. We conducted a single-center, retrospective, longitudinal matched-cohort study of prospectively collected outcomes. In total, 88 consecutive patients who had undergone pedicle screw instrumentation for thoracolumbar burst fracture with successful fusion confirmed by computed tomography (CT) were used in this study. In total, 45 patients wanted to undergo implant removal surgery (R group), and 43 decided not to remove the implant (NR group). A CUA was conducted from the health care perspective. The direct costs of health care were obtained from the medical bill of each patient. Changes in health-related quality of life (HRQoL) scores, validated by Short Form 6D, were used to calculate quality-adjusted life-years (QALYs). Total costs and gained QALY were calculated at 1 year (1 year) and 2 years (2 years) compared with baseline. Results are expressed as an incremental cost-effectiveness ratio (ICER). Different discount rates (0%, 3%, and 5%) were applied to both cost and QALY for sensitivity analysis. Baseline patient variables were similar between the two groups (all P > 0.05). The additional benefits of implant removal (0.201 QALY at 2 years) were achieved with additional costs ($2541 at 2 years), equating to an ICER of $12,641/QALY. On the basis of the different discount rates, the robustness of our study's results was also determined. Implant removal after successful fusion in a thoracolumbar burst

[Longitudinal preputial pedicled flap urethroplasty for chordee of Donnahoo type IV].

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Zeng, Li; Shan, Wei; Yuan, Miao; Huang, Guizhen; Huang, Lugang

2012-11-01

To investigate the effectiveness of longitudinal preputial pedicled flap urethroplasty for chordee of Donnahoo IV type. Between June 1994 and October 2011, 30 patients with chordee (Donnahoo type IV) underwent longitudinal preputial pedicled flap urethroplasty. The patients' age ranged from 2 to 16 years (mean, 5.8 years). The morphology of the balanus-navicular fossa-external urethral orifice ranged normal; the penis length was 2.5-6.8 cm (mean, 4.3 cm); the penis bending angle was 35-70 degrees (mean, 40.1 degrees). Primary and secondary operation was 27 cases and 3 cases, respectively. The size of flap ranged from 1.5 cm x 1.3 cm to 4.0 cm x 2.0 cm. After correction, the penis length was 3.0-8.5 cm (mean, 6.6 cm); the penis bending angle was 0-10 degrees (mean, 1.2 degrees). All patients were followed up 6 months to 12 years (mean, 33 months). No recurrence, stabbing pain of the balanus, or foreign body sensation occurred during follow-up. Of them, 4 patients (13.33%) had urinary fistular, they had satisfactory results after the second operation; 2 patients (6.67%) had urethral stricture 1 month after operation, they also had satisfactory results after arethral dilatation. The other patients showed no scattering urinary flow and good direction without complication. Six patients had satisfactory sexual function after puberty without erection disorder, pain, or dyspareunia. Longitudinal preputial pedicled flap urethroplasty can achieve maximum utilization of prepuce and aesthetic and functional improvement with less complication, so it is a relatively ideal mean for treating chordee of Donnahoo type IV.

Laparoscopic Navigated Liver Resection: Technical Aspects and Clinical Practice in Benign Liver Tumors

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Markus Kleemann

2012-01-01

Full Text Available Laparoscopic liver resection has been performed mostly in centers with an extended expertise in both hepatobiliary and laparoscopic surgery and only in highly selected patients. In order to overcome the obstacles of this technique through improved intraoperative visualization we developed a laparoscopic navigation system (LapAssistent to register pre-operatively reconstructed three-dimensional CT or MRI scans within the intra-operative field. After experimental development of the navigation system, we commenced with the clinical use of navigation-assisted laparoscopic liver surgery in January 2010. In this paper we report the technical aspects of the navigation system and the clinical use in one patient with a large benign adenoma. Preoperative planning data were calculated by Fraunhofer MeVis Bremen, Germany. After calibration of the system including camera, laparoscopic instruments, and the intraoperative ultrasound scanner we registered the surface of the liver. Applying the navigated ultrasound the preoperatively planned resection plane was then overlain with the patient's liver. The laparoscopic navigation system could be used under sterile conditions and it was possible to register and visualize the preoperatively planned resection plane. These first results now have to be validated and certified in a larger patient collective. A nationwide prospective multicenter study (ProNavic I has been conducted and launched.

Robot-Assisted Free Flap in Head and Neck Reconstruction

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Han Gyeol Song

2013-07-01

Full Text Available Background  Robots have allowed head and neck surgeons to extirpate oropharyngealtumors safely without the need for lip-split incision or mandibulotomy. Using robots inoropharyngealreconstruction is newbut essentialfor oropharyngeal defectsthatresultfromrobotic tumor excision. We report our experience with robotic free-flap reconstruction ofhead and neck defectsto exemplify the necessity forrobotic reconstruction.Methods  We investigated head and neck cancer patients who underwent ablation surgeryand free-flap reconstruction by robot. Between July 1, 2011 andMarch 31, 2012, 5 caseswereperformed and patient demographics, location of tumor, pathologic stage, reconstructionmethods, flap size, recipient vessel, necessary pedicle length, and operation time wereinvestigated.Results  Among five free-flap reconstructions, four were radial forearm free flaps and onewas an anterolateral thigh free-flap. Four flaps used the superior thyroid artery and oneflap used a facial artery as the recipient vessel. The average pedicle length was 8.8 cm. Flapinsetting and microanastomosis were achieved using a specially manufactured roboticinstrument. The total operation timewas 1,041.0 minutes(range, 814 to 1,132 minutes, andcomplicationsincluding flap necrosis, hematoma, andwound dehiscence did not occur.Conclusions  Thisstudy demonstratesthe clinically applicable use ofrobotsin oropharyngealreconstruction, especially using a free flap. A robot can assist the operator in insettingthe flap at a deep portion of the oropharynx without the need to perform a traditionalmandibulotomy. Robot-assisted reconstruction may substitute for existing surgical methodsand is accepted asthemost up-to-datemethod.

Clinical study on the application of minimally invasive percutaneous pedicle screw fixation in single segment thoracolumbar fracture without neurological symptoms

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Jin-ping LIU

2016-04-01

Full Text Available Objective To discuss the clinical effects of minimally invasive percutaneous pedicle screw fixation in the treatment of single segment thoracolumbar fracture without neurological symptoms.  Methods From June 2012 to October 2014, 38 neurologically intact patients with thoracolumbar fracture underwent surgeries, including open pedicle screw fixation in 16 cases and percutaneous pedicle screw fixation in 22 cases. The incision length, operation time, intraoperative blood loss, postoperative drainage and postoperative complication were recorded and compared between 2 groups. Thoracolumbar orthophoric, lateral and flexion-extension X-ray was used to measure sagittal Cobb angle and height of injured anterior vertebral body before and after operation. Modified Macnab evaluation was used to assess the curative effects 3 months after operation. Results The success rate of operations in 38 patients was 100%. There were a total of 114 vertebral bodies fused and 228 pedicle screws implanted. Patients in the percutaneous pedicle screw group had smaller incision length [(10.55 ± 1.23 cm vs (18.50 ± 2.50 cm, P = 0.000], less intraoperative blood loss [(32.55 ± 7.22 ml vs (320.50 ± 15.48 ml, P = 0.000], shorter hospital stay [(6.55 ± 1.50 d vs (13.50 ± 2.52 d, P = 0.000], and without postoperative drainage. The follow-up after operation ranged from 3 to 6 months, with the average time of (4.65 ± 1.24 months. Cobb angle was reduced (P = 0.000 and height of injured anterior vertebral body were improved signifcantly (P = 0.000 3 months after surgery in both groups. The total effective rate was 14/16 in open surgery group, and 86.36% (19/22 in percutaneous pedicle screw group, however, the difference between 2 groups was not significant (P = 1.000. Conclusions Minimally invasive percutaneous pedicle screw fixation is a surgical method with less iatrogenic injury, less intraoperative blood loss and quick recovery for patients with thoracolumbar fracture

The transverse penile pedicled flap urethroplasty: description of a simplified technique for the dissection of the Fascio-cutaneous flap.

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Shittu, O B; Sotunmbi, P T

2015-06-01

Urethroplasty is often required for long urethral strictures or urethral strictures that have recurred after repeated urethral dilatations or urethrotomy. The transvers penile skin pedicled flap is very versatile for the reconstruction of long urethral stricture. However the meticulous sharp dissection required to develop it takes a long time to do and may be associated with button hole injuries to the vascular pedicle and the penile skin. We describe a simplified technique of raising the flap which does not require sharp dissection and is very quick to accomplish. Technique involves using a circumcising distal penile shaft skin incision to de-glove the penis by blunt dissection. The skin substitute, adequate to give appropriate urethra calibre is similarly dissected bluntly along with its vascular pedicle from the proximal penile skin. The techniques used to facilitate successful blunt dissection are described. In 9 adults with long, multiple urethral strictures, the average time to develop the flap was 15 minutes and complication have been limited to temporary urethro-cutaneous fistula at the ventral part of the circular skin closure. These fistulae closed on conservative treatment. No patient suffered button-hole injuries to either the vascular pedicle or the penile skin. This modification to the standard sharp dissection is very quick to accomplish. It also avoids the creation of button-hole injuries to either the vascular pedicle or the penile skin. It should make the use of this versatile flap more attractive in the reconstruction of long urethral strictures in those who may wish to use this option for reconstruction of long urethral strictures.

Neurosurgical robotic arm drilling navigation system.

Science.gov (United States)

Lin, Chung-Chih; Lin, Hsin-Cheng; Lee, Wen-Yo; Lee, Shih-Tseng; Wu, Chieh-Tsai

2017-09-01

The aim of this work was to develop a neurosurgical robotic arm drilling navigation system that provides assistance throughout the complete bone drilling process. The system comprised neurosurgical robotic arm navigation combining robotic and surgical navigation, 3D medical imaging based surgical planning that could identify lesion location and plan the surgical path on 3D images, and automatic bone drilling control that would stop drilling when the bone was to be drilled-through. Three kinds of experiment were designed. The average positioning error deduced from 3D images of the robotic arm was 0.502 ± 0.069 mm. The correlation between automatically and manually planned paths was 0.975. The average distance error between automatically planned paths and risky zones was 0.279 ± 0.401 mm. The drilling auto-stopping algorithm had 0.00% unstopped cases (26.32% in control group 1) and 70.53% non-drilled-through cases (8.42% and 4.21% in control groups 1 and 2). The system may be useful for neurosurgical robotic arm drilling navigation. Copyright © 2016 John Wiley & Sons, Ltd.

[A case of transverse colon cancer with multiple liver metastases and hepatic pedicle lymph node involvement showing pathological complete response by XELOX plus bevacizumab].

Science.gov (United States)

Mukai, Toshiki; Akiyoshi, Takashi; Koga, Rintaro; Arita, Junichi; Saiura, Akio; Ikeda, Atsushi; Nagasue, Yasutomo; Oikawa, Yoshinori; Yamakawa, Keiko; Konishi, Tsuyoshi; Fujimoto, Yoshiya; Nagayama, Satoshi; Fukunaga, Yosuke; Ueno, Masashi; Suenaga, Mitsukuni; Mizunuma, Nobuyuki; Shinozaki, Eiji; Yamamoto, Chiriko; Yamaguchi, Toshiharu

2012-12-01

A 70-year-old woman was referred to our hospital because of abdominal pain. Abdominal computed tomography(CT)and colonoscopy revealed transverse colon cancer with multiple liver metastases, with involvement of the hepatic pedicle and superior mesenteric artery lymph nodes. The patient received eight courses of XELOX plus bevacizumab, and CT showed a decrease in the size of the liver metastases and hepatic pedicle lymphadenopathy. Right hemicolectomy, partial hepatectomy, and hepatic pedicle lymph node resection were performed. Histopathological examination of the resected tissue revealed no residual cancer cells, suggesting a pathological complete response. The patient remains well 7 months after operation, without any signs of recurrence. Surgical resection should be considered for patients with initially unresectable colon cancer with liver metastases and hepatic pedicle lymph nodes involvement if systemic chemotherapy is effective.

Use of next generation sequencing to detect biofilm bacteria in a patient with pedicle screw loosening after spine surgery

DEFF Research Database (Denmark)

Xu, Yijuan; Thomsen, Trine Rolighed; Lorenzen, Jan

2016-01-01

2. Center for Microbial Communities, Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, Denmark 3. Otto-von-Guericke University Magdeburg, Department of Orthopedic Surgery, Magdeburg, Germany 4. Eifelklinik St. Brigida, Simmerath, Germany Aim: ”Hidden deep...... implant-related infection is believed to be linked to pedicle screw loosening after spine surgery. Low-grade bacterial infection can be hard to diagnose and may be undetected by conventional culture based methods. Next generation sequencing (NGS) could help to uncover hidden bacterial infections...... as a possible cause for implant loosening. This case report describes the use of NGS in the diagnostic work-up of a patient with pedicle screw loosening after spine surgery.” Method: ”A 60 y/o male had to undergo revision spine surgery for pedicle screw loosening and adjacent segment disease 3 years after...

Pedicle frozen autograft for limb sparing surgery in a dog with femoral osteosarcoma

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Aline Silva Gouvêa

Full Text Available ABSTRACT: Osteosarcoma (OSA is the most common bone tumor diagnosed in dogs and represents approximately 85% of canine skeletal tumors. The most commonly employed therapy is amputation of the limb followed by chemotherapy. However, preservation of the afflicted limb has been successful for patients with concomitant neurological or orthopedic conditions, which are contraindications to the complete amputation, or with owners reluctant to the possibility of amputation. For these reasons, the purpose of this study was to describe the technical procedures that allowed limb salvage through the use of pedicle frozen grafts in a dog with femoral OSA. Surgical procedures consisted of a femoral diaphyseal osteotomy with tearing of the soft tissues; thus, creating a bone pedicle that was frozen in liquid nitrogen according to the protocol outlined by TSUCHIYA et al. (2005. Limb function remained satisfactory for six months.

The accuracy and safety of fluoroscopically guided percutaneous pedicle screws in the lumbosacral junction and the lumbar spine: a review of 880 screws.

Science.gov (United States)

Chiu, C K; Kwan, M K; Chan, C Y W; Schaefer, C; Hansen-Algenstaedt, N

2015-08-01

We undertook a retrospective study investigating the accuracy and safety of percutaneous pedicle screws placed under fluoroscopic guidance in the lumbosacral junction and lumbar spine. The CT scans of patients were chosen from two centres: European patients from University Medical Center Hamburg-Eppendorf, Germany, and Asian patients from the University of Malaya, Malaysia. Screw perforations were classified into grades 0, 1, 2 and 3. A total of 880 percutaneous pedicle screws from 203 patients were analysed: 614 screws from 144 European patients and 266 screws from 59 Asian patients. The mean age of the patients was 58.8 years (16 to 91) and there were 103 men and 100 women. The total rate of perforation was 9.9% (87 screws) with 7.4% grade 1, 2.0% grade 2 and 0.5% grade 3 perforations. The rate of perforation in Europeans was 10.4% and in Asians was 8.6%, with no significant difference between the two (p = 0.42). The rate of perforation was the highest in S1 (19.4%) followed by L5 (14.9%). The accuracy and safety of percutaneous pedicle screw placement are comparable to those cited in the literature for the open method of pedicle screw placement. Greater caution must be taken during the insertion of L5 and S1 percutaneous pedicle screws owing to their more angulated pedicles, the anatomical variations in their vertebral bodies and the morphology of the spinal canal at this location. ©2015 The British Editorial Society of Bone & Joint Surgery.

Correction Capability in the 3 Anatomic Planes of Different Pedicle Screw Designs in Scoliosis Instrumentation.

Science.gov (United States)

Wang, Xiaoyu; Aubin, Carl-Eric; Coleman, John; Rawlinson, Jeremy

2017-05-01

Computer simulations to compare the correction capabilities of different pedicle screws in adolescent idiopathic scoliosis (AIS) instrumentations. To compare the correction and resulting bone-screw forces associated with different pedicle screws in scoliosis instrumentations. Pedicle screw fixation is widely used in surgical instrumentation for spinal deformity treatment. Screw design, correction philosophies, and surgical techniques are constantly evolving to achieve better control of the vertebrae and correction of the spinal deformity. Yet, there remains a lack of biomechanical studies that quantify the effects and advantages of different screw designs in terms of correction kinematics. The correction capabilities of fixed-angle, multiaxial, uniaxial, and saddle axial screws were kinematically analyzed, simulated, and compared. These simulations were based on the screw patterns and correction techniques proposed by 2 experienced surgeons for 2 AIS cases. Additional instrumentations were assessed to compare the correction and resulting bone-screw forces associated with each type of screw. The fixed-angle, uniaxial and saddle axial screws had similar kinematic behavior and performed better than multiaxial screws in the coronal and transverse planes (8% and 30% greater simulated corrections, respectively). Uniaxial and multiaxial screws were less effective than fixed-angle and saddle axial screws in transmitting compression/distraction to the anterior spine because of their sagittal plane mobility between the screw head and shank. Only the saddle axial screws allow vertebra angle in the sagittal plane to be independently adjusted. Pedicle screws of different designs performed differently for deformity corrections or for compensating screw placement variations in different anatomic planes. For a given AIS case, screw types should be determined based on the particular instrumentation objectives, the deformity's stiffness and characteristics so as to make the best of

Radiofrequency-activated PMMA-augmentation through cannulated pedicle screws: A cadaver study to determine the biomechanical benefits in the osteoporotic spine.

Science.gov (United States)

Karius, T; Deborre, C; Wirtz, D C; Burger, C; Prescher, A; Fölsch, A; Kabir, K; Pflugmacher, R; Goost, H

2017-01-01

PMMA-augmentation of pedicle screws strengthens the bone-screw-interface reducing cut-out risk. Injection of fluid cement bears a higher risk of extravasation, with difficulty of application because of inconsistent viscosity and limited injection time. To test a new method of cement augmentation of pedicle screws using radiofrequency-activated PMMA, which is suspected to be easier to apply and have less extravasations. Twenty-seven fresh-frozen human cadaver lumbar spines were divided into 18 osteoporotic (BMD ≤ 0.8 g/cm2) and 9 non-osteoporotic (BMD > 0.8 g/cm2) vertebral bodies. Bipedicular cannulated pedicle screws were implanted into the vertebral bodies; right screws were augmented with ultra-high viscosity PMMA, whereas un-cemented left pedicle screws served as negative controls. Cement distribution was controlled with fluoroscopy and CT scans. Axial pullout forces of the screws were measured with a material testing machine, and results were analyzed statistically. Fluoroscopy and CT scans showed that in all cases an adequately big cement depot with homogenous form and no signs of extravasation was injected. Pullout forces showed significant differences (p < 0.001) between the augmented and non-augmented pedicle screws for bone densities below 0.8 g/cm2 (661.9 N ± 439) and over 0.8 g/cm2 (744.9 N ± 415). Pullout-forces were significantly increased in osteoporotic as well as in non-osteoporotic vertebral bodies without a significant difference between these groups using this standardized, simple procedure with increased control and less complications like extravasation.

CONTEMPORARY VIEW ON COMPUTER NAVIGATION USING AT PRIMARY KNEE TOTAL REPLACEMENT (REVIEW

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A. I. Petukhov

2010-01-01

Full Text Available The topical questions of optical computer navigation at knee total arthroplasty are widely covered. The indications, contraindication to use, using features and possible complications of this technique are listed. The analysis of literature data makes it clear that computer navigation assists in the accuracy of endoprosthesis implantation that may to decrease the rate of revision surgeries in future.

Neural-network-based depth computation for blind navigation

Science.gov (United States)

Wong, Farrah; Nagarajan, Ramachandran R.; Yaacob, Sazali

2004-12-01

A research undertaken to help blind people to navigate autonomously or with minimum assistance is termed as "Blind Navigation". In this research, an aid that could help blind people in their navigation is proposed. Distance serves as an important clue during our navigation. A stereovision navigation aid implemented with two digital video cameras that are spaced apart and fixed on a headgear to obtain the distance information is presented. In this paper, a neural network methodology is used to obtain the required parameters of the camera which is known as camera calibration. These parameters are not known but obtained by adjusting the weights in the network. The inputs to the network consist of the matching features in the stereo pair images. A back propagation network with 16-input neurons, 3 hidden neurons and 1 output neuron, which gives depth, is created. The distance information is incorporated into the final processed image as four gray levels such as white, light gray, dark gray and black. Preliminary results have shown that the percentage errors fall below 10%. It is envisaged that the distance provided by neural network shall enable blind individuals to go near and pick up an object of interest.

[Pedicled superior gluteal artery perforator bilateral quadrilobed flaps for repair of large sacrococcygeal pressure sores].

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Hai, Henglin; Li, Huatao; Chen, Yang; Li, Qiang; Wu, Shenggang; Lili, Wang; Yan, Lei; Xiaoying, Zhou

2013-03-01

To investigate the effectiveness of pedicled superior gluteal artery perforator bilateral quadrilobed flaps for repairing large sacrococcygeal pressure sores. Between June 2003 and August 2011, 6 paraplegia patients with large sacrococcygeal pressure sores were repaired with the pedicled superior gluteal artery perforator bilateral quadrilobed flaps. There were 2 males and 4 females with an average age of 45.6 years (range, 37-62 years). The mean disease duration was 8.4 months (range, 3-26 months). According to National Pressure Ulcer Advisory Panel (NPUAP) standard, 6 cases rated as degree IV. The size of pressure sores ranged from 15 cm x 13 cm to 18 cm x 16 cm. The size of flaps ranged from 18 cm x 14 cm to 21 cm x 15 cm. After operation, all flaps survived successfully. The wounds healed by first intention in 5 cases; partial dehiscence of incision occurred in 1 case, which was cured after dressing change for 26 days. Six patients were followed up 6-24 months (mean, 12.5 months). The appearance and texture of the flaps were smooth and soft with good elasticity and no ulceration. Pedicled superior gluteal artery perforator bilateral quadrilobed flaps can repair large sacrococcygeal pressure sores. The appearance of flaps is smooth and has good compression-resistance effect.

Paediatric patient navigation models of care in Canada: An environmental scan.

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Luke, Alison; Doucet, Shelley; Azar, Rima

2018-05-01

(1) To provide other organizations with useful information when implementing paediatric navigation programs and (2) to inform the implementation of a navigation care centre in New Brunswick for children with complex health conditions. This environmental scan consisted of a literature review of published and grey literature for paediatric patient navigation programs across Canada. Additional programs were found following discussions with program coordinators and navigators. Interviews were conducted with key staff from each program and included questions related to patient condition; target population and location; method delivery; navigator background; and navigator roles. Data analysis included analysis of interviews and identification of common themes across the different programs. We interviewed staff from 19 paediatric navigation programs across Canada. Programs varied across a number of different themes, including: condition and disease type, program location (e.g., hospital or clinic), navigator background (e.g., registered nurse or peer/lay navigator) and method of delivery (e.g., phone or face-to-face). Overall, navigator roles are similar across all programs, including advocacy, education, support and assistance in accessing resources from both within and outside the health care system. This scan offers a road map of Canadian paediatric navigation programs. Knowledge learned from this scan will inform stakeholders who are either involved in the delivery of paediatric patient navigation programs or planning to implement such a program. Specifically, our scan informed the development of a navigation centre for children with complex health conditions in New Brunswick.

Intraoperative computed tomography with integrated navigation system in spinal stabilizations.

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Zausinger, Stefan; Scheder, Ben; Uhl, Eberhard; Heigl, Thomas; Morhard, Dominik; Tonn, Joerg-Christian

2009-12-15

STUDY DESIGN.: A prospective interventional case-series study plus a retrospective analysis of historical patients for comparison of data. OBJECTIVE.: To evaluate workflow, feasibility, and clinical outcome of navigated stabilization procedures with data acquisition by intraoperative computed tomography. SUMMARY OF BACKGROUND DATA.: Routine fluoroscopy to assess pedicle screw placement is not consistently reliable. Our hypothesis was that image-guided spinal navigation using an intraoperative CT-scanner can improve the safety and precision of spinal stabilization surgery. METHODS.: CT data of 94 patients (thoracolumbar [n = 66], C1/2 [n = 12], cervicothoracic instability [n = 16]) were acquired after positioning the patient in the final surgical position. A sliding gantry 40-slice CT was used for image acquisition. Data were imported to a frameless infrared-based neuronavigation workstation. Intraoperative CT was obtained to assess the accuracy of instrumentation and, if necessary, the extent of decompression. All patients were clinically evaluated by Odom-criteria after surgery and after 3 months. RESULTS.: Computed accuracy of the navigation system reached /=2 mm without persistent neurologic or vascular damage in 20/414 screws (4.8%) leading to immediate correction of 10 screws (2.4%). Control-iCT changed the course of surgery in 8 cases (8.5% of all patients). The overall revision rate was 8.5% (4 wound revisions, 2 CSF fistulas, and 2 epidural hematomas). There was no reoperation due to implant malposition. According to Odom-criteria all patients experienced a clinical improvement. A retrospective analysis of 182 patients with navigated thoracolumbar transpedicular stabilizations in the preiCT era revealed an overall revision rate of 10.4% with 4.4% of patients requiring screw revision. CONCLUSION.: Intraoperative CT in combination with neuronavigation provides high accuracy of screw placement and thus safety for patients undergoing spinal stabilization

Asymmetry of the Vertebral Body and Pedicles in the True Transverse Plane in Adolescent Idiopathic Scoliosis: A CT-Based Study.

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Brink, Rob C; Schlösser, Tom P C; Colo, Dino; Vincken, Koen L; van Stralen, Marijn; Hui, Steve C N; Chu, Winnie C W; Cheng, Jack C Y; Castelein, René M

2017-01-01

Cross-sectional. To quantify the asymmetry of the vertebral bodies and pedicles in the true transverse plane in adolescent idiopathic scoliosis (AIS) and to compare this with normal anatomy. There is an ongoing debate about the existence and magnitude of the vertebral body and pedicle asymmetry in AIS and whether this is an expression of a primary growth disturbance, or secondary to asymmetrical loading. Vertebral body asymmetry, defined as left-right overlap of the vertebral endplates (ie, 100%: perfect symmetry, 0%: complete asymmetry) was evaluated in the true transverse plane on CT scans of 77 AIS patients and 32 non-scoliotic controls. Additionally, the pedicle width, length, and angle and the length of the ideal screw trajectory were calculated. Scoliotic vertebrae were on average more asymmetric than controls (thoracic: AIS 96.0% vs. controls 96.4%; p = .005, lumbar: 95.8% vs. 97.2%; p transverse pedicle angle was greater (12.3° vs. 5.7°; p transverse plane in AIS and no uniform relation between the axial rotation and vertebral asymmetry could be observed in these moderate to severe patients, suggesting that asymmetrical vertebral growth does not initiate rotation, but rather follows it as a secondary phenomenon. Level 4. Copyright © 2016 Scoliosis Research Society. Published by Elsevier Inc. All rights reserved.

Blind's Eye: Employing Google Directions API for Outdoor Navigation of Visually Impaired Pedestrians

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SABA FEROZMEMON

2017-07-01

Full Text Available Vision plays a paramount role in our everyday life and assists human in almost every walk of life. The people lacking vision sense require assistance to move freely. The inability of unassisted navigation and orientation in outdoor environments is one of the most important constraints for people with visual impairment. Motivated by this problem, we developed a simplified and user friendly navigation system that allows visually impaired pedestrians to reach their desired outdoor location. We designed a Braille keyboard to allow the blind user to input their destination. The proposed system makes use of Google Directions API (Application Program Interface to generate the right path to a destination. The visually impaired pedestrians have to wear a vibration belt to keep them on the track. The evaluation exposes shortcomings of Google Directions API when used for navigating the visually impaired pedestrians in an outdoor environment.

A Novel Pedicle Screw with Mobile Connection: A Pilot Study

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Yasuaki Tokuhashi

2014-01-01

Full Text Available To prevent adjacent disc problems after spinal fusion, a pedicle screw with a mobile junction between the head and threaded shaft was newly developed. The threaded shaft of the screw has 10 degrees mobility in all directions, but its structure is to prevent abnormal translation and tilting. This screw was evaluated as follows: (1 endurance test: 106 times rotational stress was applied; (2 biological reactions: novel screws with a mobile head and conventional screws with a fixed head were inserted into the bilateral pedicles of the L3, L4, and L5 in two mini pigs with combination. Eight months after surgery, vertebral units with the screw rod constructs were collected. After CT scan, the soft and bony tissues around the screws were examined grossly and histologically. As a result, none of the screws broke during the endurance test stressing. The mean amount of abrasion wear was 0.0338 g. In the resected mini pig section, though zygapophyseal joints between fixed-head screws showed bony union, the amount of callus in the zygapophyseal joints connected with mobile-head screws was small, and joint space was confirmed by CT. No metalloses were noted around any of the screws. Novel screws were suggested to be highly durable and histologically safe.

New orthopaedic implant management tool for computer-assisted planning, navigation, and simulation: from implant CAD files to a standardized XML-based implant database.

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Sagbo, S; Blochaou, F; Langlotz, F; Vangenot, C; Nolte, L-P; Zheng, G

2005-01-01

Computer-Assisted Orthopaedic Surgery (CAOS) has made much progress over the last 10 years. Navigation systems have been recognized as important tools that help surgeons, and various such systems have been developed. A disadvantage of these systems is that they use non-standard formalisms and techniques. As a result, there are no standard concepts for implant and tool management or data formats to store information for use in 3D planning and navigation. We addressed these limitations and developed a practical and generic solution that offers benefits for surgeons, implant manufacturers, and CAS application developers. We developed a virtual implant database containing geometrical as well as calibration information for orthopedic implants and instruments, with a focus on trauma. This database has been successfully tested for various applications in the client/server mode. The implant information is not static, however, because manufacturers periodically revise their implants, resulting in the deletion of some implants and the introduction of new ones. Tracking these continuous changes and keeping CAS systems up to date is a tedious task if done manually. This leads to additional costs for system development, and some errors are inevitably generated due to the huge amount of information that has to be processed. To ease management with respect to implant life cycle, we developed a tool to assist end-users (surgeons, hospitals, CAS system providers, and implant manufacturers) in managing their implants. Our system can be used for pre-operative planning and intra-operative navigation, and also for any surgical simulation involving orthopedic implants. Currently, this tool allows addition of new implants, modification of existing ones, deletion of obsolete implants, export of a given implant, and also creation of backups. Our implant management system has been successfully tested in the laboratory with very promising results. It makes it possible to fill the current gap

Comparison of low density and high density pedicle screw instrumentation in Lenke 1 adolescent idiopathic scoliosis.

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Shen, Mingkui; Jiang, Honghui; Luo, Ming; Wang, Wengang; Li, Ning; Wang, Lulu; Xia, Lei

2017-08-02

The correlation between implant density and deformity correction has not yet led to a precise conclusion in adolescent idiopathic scoliosis (AIS). The aim of this study was to evaluate the effects of low density (LD) and high density (HD) pedicle screw instrumentation in terms of the clinical, radiological and Scoliosis Research Society (SRS)-22 outcomes in Lenke 1 AIS. We retrospectively reviewed 62 consecutive Lenke 1 AIS patients who underwent posterior spinal arthrodesis using all-pedicle screw instrumentation with a minimum follow-up of 24 months. The implant density was defined as the number of screws per spinal level fused. Patients were then divided into two groups according to the average implant density for the entire study. The LD group (n = 28) had fewer than 1.61 screws per level, while the HD group (n = 34) had more than 1.61 screws per level. The radiographs were analysed preoperatively, postoperatively and at final follow-up. The perioperative and SRS-22 outcomes were also assessed. Independent sample t tests were used between the two groups. Comparisons between the two groups showed no significant differences in the correction of the main thoracic curve and thoracic kyphosis, blood transfusion, hospital stay, and SRS-22 scores. Compared with the HD group, there was a decreased operating time (278.4 vs. 331.0 min, p = 0.004) and decreased blood loss (823.6 vs. 1010.9 ml, p = 0.048), pedicle screws needed (15.1 vs. 19.6, p density and high density pedicle screw instrumentation achieved satisfactory deformity correction in Lenke 1 AIS patients. However, the operating time and blood loss were reduced, and the implant costs were decreased with the use of low screw density constructs.

Factors affecting femoral rotational angle based on the posterior condylar axis in gap-based navigation-assisted total knee arthroplasty for valgus knee.

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Lee, Sung-Sahn; Lee, Yong-In; Kim, Dong-Uk; Lee, Dae-Hee; Moon, Young-Wan

2018-01-01

Achieving proper rotational alignment of the femoral component in total knee arthroplasty (TKA) for valgus knee is challenging because of lateral condylar hypoplasia and lateral cartilage erosion. Gap-based navigation-assisted TKA enables surgeons to determine the angle of femoral component rotation (FCR) based on the posterior condylar axis. This study evaluated the possible factors that affect the rotational alignment of the femoral component based on the posterior condylar axis. Between 2008 and 2016, 28 knees were enrolled. The dependent variable for this study was FCR based on the posterior condylar axis, which was obtained from the navigation system archives. Multiple regression analysis was conducted to identify factors that might predict FCR, including body mass index (BMI), Kellgren-Lawrence grade (K-L grade), lateral distal femoral angles obtained from the navigation system and radiographs (NaviLDFA, XrayLDFA), hip-knee-ankle (HKA) axis, lateral gap under varus stress (LGVS), medial gap under valgus stress (MGVS), and side-to-side difference (STSD, MGVS - LGVS). The mean FCR was 6.1° ± 2.0°. Of all the potentially predictive factors evaluated in this study, only NaviLDFA (β = -0.668) and XrayLDFA (β = -0.714) predicted significantly FCR. The LDFAs, as determined using radiographs and the navigation system, were both predictive of the rotational alignment of the femoral component based on the posterior condylar axis in gap-based TKA for valgus knee. A 1° increment with NaviLDFA led to a 0.668° decrement in FCR, and a 1° increment with XrayLDFA led to a 0.714° decrement. This suggests that symmetrical lateral condylar hypoplasia of the posterior and distal side occurs in lateral compartment end-stage osteoarthritis with valgus deformity.

Basic research and 12 years of clinical experience in computer-assisted navigation technology: a review.

Science.gov (United States)

Ewers, R; Schicho, K; Undt, G; Wanschitz, F; Truppe, M; Seemann, R; Wagner, A

2005-01-01

Computer-aided surgical navigation technology is commonly used in craniomaxillofacial surgery. It offers substantial improvement regarding esthetic and functional aspects in a range of surgical procedures. Based on augmented reality principles, where the real operative site is merged with computer generated graphic information, computer-aided navigation systems were employed, among other procedures, in dental implantology, arthroscopy of the temporomandibular joint, osteotomies, distraction osteogenesis, image guided biopsies and removals of foreign bodies. The decision to perform a procedure with or without computer-aided intraoperative navigation depends on the expected benefit to the procedure as well as on the technical expenditure necessary to achieve that goal. This paper comprises the experience gained in 12 years of research, development and routine clinical application. One hundred and fifty-eight operations with successful application of surgical navigation technology--divided into five groups--are evaluated regarding the criteria "medical benefit" and "technical expenditure" necessary to perform these procedures. Our results indicate that the medical benefit is likely to outweight the expenditure of technology with few exceptions (calvaria transplant, resection of the temporal bone, reconstruction of the orbital floor). Especially in dental implantology, specialized software reduces time and additional costs necessary to plan and perform procedures with computer-aided surgical navigation.

Creation of a Bioengineered Skin Flap Scaffold with a Perfusable Vascular Pedicle.

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Jank, Bernhard J; Goverman, Jeremy; Guyette, Jacques P; Charest, Jon M; Randolph, Mark; Gaudette, Glenn R; Gershlak, Joshua R; Purschke, Martin; Javorsky, Emilia; Nazarian, Rosalynn M; Leonard, David A; Cetrulo, Curtis L; Austen, William G; Ott, Harald C

2017-07-01

Full-thickness skin loss is a challenging problem due to limited reconstructive options, demanding 75 million surgical procedures annually in the United States. Autologous skin grafting is the gold standard treatment, but results in donor-site morbidity and poor aesthetics. Numerous skin substitutes are available on the market to date, however, none truly functions as full-thickness skin due to lack of a vascular network. The creation of an autologous full-thickness skin analogue with a vascular pedicle would result in a paradigm shift in the management of wounds and in reconstruction of full-thickness skin defects. To create a clinically relevant foundation, we generated an acellular skin flap scaffold (SFS) with a perfusable vascular pedicle of clinically relevant size by perfusion decellularization of porcine fasciocutaneous flaps. We then analyzed the yielded SFS for mechanical properties, biocompatibility, and regenerative potential in vitro and in vivo. Furthermore, we assessed the immunological response using an in vivo model. Finally, we recellularized the vascular compartment of an SFS and reconnected it to a recipient's blood supply to test for perfusability. Perfusion decellularization removed all cellular components with preservation of native extracellular matrix composition and architecture. Biaxial testing revealed preserved mechanical properties. Immunologic response and biocompatibility assessed via implantation and compared with native xenogenic skin and commercially available dermal substitutes revealed rapid neovascularization and complete tissue integration. Composition of infiltrating immune cells showed no evidence of allorejection and resembled the inflammatory phase of wound healing. Implantation into full-thickness skin defects demonstrated good tissue integration and skin regeneration without cicatrization. We have developed a protocol for the generation of an SFS of clinically relevant size, containing a vascular pedicle, which can be

Unilateral pedicle screws asymmetric tethering: an innovative method to create idiopathic deformity

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Zhang Xuesong

2007-10-01

Full Text Available Abstract Objective To evaluate the feasibility of the method that unilateral pedicle screws asymmetric tethering in concave side in combination with convex rib resection for creating idiopathic deformity. Summary of background data Various methods are performed to create idiopathic deformity. Among these methods, posterior asmmetric tethering of the spine shows satisfying result, but some drawbacks related to the current posterior asymmetric tether were still evident. Materials and methods Unilateral pedicle screws asymmetric tethering was performed to 14 female goats (age: 5–8 week-old, weight: 6–8 kg in concave side in combination with convex rib resection. Dorsoventral and lateral plain radiographs were taken of each thoracic spine in the frontal and sagittal planes right after the surgery and later every 4 weeks. Results All animals ambulated freely after surgery. For technical reasons, 2 goats were excluded (one animal died for anesthetic during the surgery, and one animal was lost for instrumental fail due to postoperative infection. Radiography showed that 11 goats exhibited scoliosis with convex toward to the right side, and as the curve increased with time, only 1 goat showed nonprogressive. The initial scoliosis generated in the progressors after the procedures measured 29.0° on average (range 23.0°–38.5° and increased to 43.0° on average (range 36.0°–58.0° over 8 to 10 weeks. The average progression of 14.0° was measured. The curvature immediately after tethering surgery (the initial Cobb angle did have a highly significant correlation with the final curvature (p Conclusion Unilateral pedicle screws asymmetric tethering is a practical method to create experimental scoliosis, especially for those who would like to study the correction of this deformity.

The Pedicled LICAP Flap Combined with a Free Abdominal Flap In Autologous Breast Reconstructions

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Thomas Sjøberg, MD

2018-01-01

Conclusion:. In selected patients with insufficient abdominal flap tissue, a combination of a free abdominal flap and a pedicled LICAP flap is a valuable option to increase breast size and cosmetic outcome. Additional symmetrizing surgery might still be necessary.

Occurance of aldehyde-fuchsin and performic acid-victoria blue positive granules in the ovarian pedicle of Dysdercus koenigii F. (Pyrrhocridae: Heteroptera).

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Srivastava, R C; Srivastava, B P

1976-10-15

A cycle of activity of aldehyde-fuchsin and performic acid-Victoria blue positive granules was observed in the ovarian pedicle of Dysdercus koenigii during the first ovipositional cycle. The quantitative variation of these granules in the pedicle can also be correlated directly with the increase or decrease of the neurosecretory material in the A-type cells of the pars intercerebralis medialis region of the protocerebrum of the brian.

The current status and future prospects of computer-assisted hip surgery.

Science.gov (United States)

Inaba, Yutaka; Kobayashi, Naomi; Ike, Hiroyuki; Kubota, So; Saito, Tomoyuki

2016-03-01

The advances in computer assistance technology have allowed detailed three-dimensional preoperative planning and simulation of preoperative plans. The use of a navigation system as an intraoperative assistance tool allows more accurate execution of the preoperative plan, compared to manual operation without assistance of the navigation system. In total hip arthroplasty using CT-based navigation, three-dimensional preoperative planning with computer software allows the surgeon to determine the optimal angle of implant placement at which implant impingement is unlikely to occur in the range of hip joint motion necessary for daily activities of living, and to determine the amount of three-dimensional correction for leg length and offset. With the use of computer navigation for intraoperative assistance, the preoperative plan can be precisely executed. In hip osteotomy using CT-based navigation, the navigation allows three-dimensional preoperative planning, intraoperative confirmation of osteotomy sites, safe performance of osteotomy even under poor visual conditions, and a reduction in exposure doses from intraoperative fluoroscopy. Positions of the tips of chisels can be displayed on the computer monitor during surgery in real time, and staff other than the operator can also be aware of the progress of surgery. Thus, computer navigation also has an educational value. On the other hand, its limitations include the need for placement of trackers, increased radiation exposure from preoperative CT scans, and prolonged operative time. Moreover, because the position of a bone fragment cannot be traced after osteotomy, methods to find its precise position after its movement need to be developed. Despite the need to develop methods for the postoperative evaluation of accuracy for osteotomy, further application and development of these systems are expected in the future. Copyright © 2016 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.

Visual Navigation of Complex Information Spaces

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Sarah North

1995-11-01

Full Text Available The authors lay the foundation for the introduction of visual navigation aid to assist computer users in direct manipulation of the complex information spaces. By exploring present research on scientific data visualisation and creating a case for improved information visualisation tools, they introduce the design of an improved information visualisation interface utilizing dynamic slider, called Visual-X, incorporating icons with bindable attributes (glyphs. Exploring the improvement that these data visualisations, make to a computing environment, the authors conduct an experiment to compare the performance of subjects who use traditional interfaces and Visual-X. Methodology is presented and conclusions reveal that the use of Visual-X appears to be a promising approach in providing users with a navigation tool that does not overload their cognitive processes.

Biomechanical comparative study of the stability of injectable pedicle screws with different lateral holes augmented with different volumes of polymethylmethacrylate in osteoporotic lumbar vertebrae.

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Liu, Da; Sheng, Jun; Luo, Yang; Huang, Chen; Wu, Hong-Hua; Zhou, Jiang-Jun; Zhang, Xiao-Jun; Zheng, Wei

2018-03-19

Polymethylmethacrylate (PMMA) is widely used for pedicle screw augmentation in osteoporosis. Until now, there had been no studies of the relationship between screw stability and the distribution and volume of PMMA. The objective of this study was to analyze the relationship between screw stability and the distribution pattern and injected volume of PMMA. This is a biomechanical comparison of injectable pedicle screws with different lateral holes augmented with different volumes of PMMA in cadaveric osteoporotic lumbar vertebrae. Forty-eight osteoporotic lumbar vertebrae were randomly divided into Groups A, B, and C with different pedicle screws (16 vertebrae in each group), and then each group was randomly divided into Subgroups 0, 1, 2, and 3 with different volumes of PMMA (four vertebra with eight pedicles in each subgroup). A pilot hole was prepared in advance using the same method in all samples. Type A and type B pedicle screws were directly inserted into vertebrae in Groups A and B, respectively, and then different volumes of PMMA (0, 1.0, 1.5, and 2.0 mL) were injected through the screws and into vertebrae in Subgroups 0, 1, 2, and 3. The pilot holes were filled with different volumes of PMMA (0, 1.0, 1.5, and 2.0 mL), and then the screws were inserted in Groups C0, C1, C2, and C3. Screw position and distribution of PMMA were evaluated radiographically, and axial pullout tests were performed to measure maximum axial pullout strength (F max ). Polymethylmethacrylate surrounded the anterior one-third of screws in the vertebral body in Groups A1, A2, and A3; the middle one-third of screws in the junction area of the vertebral body and the pedicle in Groups B1, B2, and B3; and the full length of screws evenly in both the vertebral body and the pedicle in Groups C1, C2, and C3. There was no malpositioning of screws or leakage of PMMA in any sample. Two-way analysis of variance revealed that two factors-distribution and volume of PMMA-significantly influenced

Multiaxial pedicle screw designs: static and dynamic mechanical testing.

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Stanford, Ralph Edward; Loefler, Andreas Herman; Stanford, Philip Mark; Walsh, William R

2004-02-15

Randomized investigation of multiaxial pedicle screw mechanical properties. Measure static yield and ultimate strengths, yield stiffness, and fatigue resistance according to an established model. Compare these measured properties with expected loads in vivo. Multiaxial pedicle screws provide surgical versatility, but the complexity of their design may reduce their strength and fatigue resistance. There is no published data on the mechanical properties of such screws. Screws were assembled according to a vertebrectomy model for destructive mechanical testing. Groups of five assemblies were tested in static tension and compression and subject to three cyclical loads. Modes of failure, yield, and ultimate strength, yield stiffness, and cycles to failure were determined for six designs of screw. Static compression yield loads ranged from 217.1 to 388.0 N and yield stiffness from 23.7 to 38.0 N/mm. Cycles to failure ranged from 42 x 10(3) to 4,719 x 10(3) at 75% of static ultimate load. There were significant differences between designs in all modes of testing. Failure occurred at the multiaxial link in static and cyclical compression. Bending yield strengths just exceeded loads expected in vivo. Multiaxial designs had lower static bending yield strength than fixed screw designs. Five out of six multiaxial screw designs achieved one million cycles at 200 N in compression bending. "Ball-in-cup" multiaxial locking mechanisms were vulnerable to fatigue failure. Smooth surfaces and thicker material appeared to be protective against fatigue failure.

Health Insurance Exchanges: Health Insurance Navigators and In-Person Assistance

Science.gov (United States)

2013-09-25

apply for coverage through the exchanges may be eligible for small business tax credits.5 Consumers may apply for coverage over the phone, online , via...more recent CMS announcements reference 20-30 hours of training. 47 The Medicare Learning Network online navigator training is estimated to take 20...about scam artists seeking to obtain personal information under the guise of verifying information regarding ACA coverage.114

Use of the Composite Pedicled Pectoralis Minor Flap after Resection of Soft Tissue Sarcoma in Reconstruction of the Glenohumeral Joint

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Michiel A. J. van de Sande

2014-01-01

Full Text Available The surgical repair of an extensive anterior glenohumeral soft tissue defect is complicated by glenohumeral instability and subsequent significant functional deficit. This surgical note offers a relatively simple reconstruction of the anterior capsule and subscapularis muscle using a pectoralis minor pedicle flap. This reconstruction is supplemented with functional reconstruction of the anterior glenohumeral joint. A conventional deltopectoral approach is utilized and pectoralis minor is freed from its coracoid insertion, released, and mobilized without compromising the pedicle entering from the dorsum and inferior one-third of the muscle. The mobilized pectoralis minor vascular pedicle has sufficient length for the pectoralis minor to be transferred to provide coverage of the anterior shoulder joint even in full external rotation, providing anterior stability. To further improve glenohumeral stability and shoulder function, the pectoralis major muscle can be split with the clavicular part reinserted lateral to the bicipital groove onto the lesser tuberosity replacing subscapularis function while stabilising the glenohumeral joint.

Towards Safe Navigation by Formalizing Navigation Rules

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Arne Kreutzmann

2013-06-01

Full Text Available One crucial aspect of safe navigation is to obey all navigation regulations applicable, in particular the collision regulations issued by the International Maritime Organization (IMO Colregs. Therefore, decision support systems for navigation need to respect Colregs and this feature should be verifiably correct. We tackle compliancy of navigation regulations from a perspective of software verification. One common approach is to use formal logic, but it requires to bridge a wide gap between navigation concepts and simple logic. We introduce a novel domain specification language based on a spatio-temporal logic that allows us to overcome this gap. We are able to capture complex navigation concepts in an easily comprehensible representation that can direcly be utilized by various bridge systems and that allows for software verification.

Navigation concepts for MR image-guided interventions.

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Moche, Michael; Trampel, Robert; Kahn, Thomas; Busse, Harald

2008-02-01

The ongoing development of powerful magnetic resonance imaging techniques also allows for advanced possibilities to guide and control minimally invasive interventions. Various navigation concepts have been described for practically all regions of the body. The specific advantages and limitations of these concepts largely depend on the magnet design of the MR scanner and the interventional environment. Open MR scanners involve minimal patient transfer, which improves the interventional workflow and reduces the need for coregistration, ie, the mapping of spatial coordinates between imaging and intervention position. Most diagnostic scanners, in contrast, do not allow the physician to guide his instrument inside the magnet and, consequently, the patient needs to be moved out of the bore. Although adequate coregistration and navigation concepts for closed-bore scanners are technically more challenging, many developments are driven by the well-known capabilities of high-field systems and their better economic value. Advanced concepts such as multimodal overlays, augmented reality displays, and robotic assistance devices are still in their infancy but might propel the use of intraoperative navigation. The goal of this work is to give an update on MRI-based navigation and related techniques and to briefly discuss the clinical experience and limitations of some selected systems. (Copyright) 2008 Wiley-Liss, Inc.

SU-F-P-42: “To Navigate, Or Not to Navigate: HDR BT in Recurrent Spine Lesions”

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Voros, L; Cohen, G; Zaider, M; Yamada, Y [Memorial Sloan-Kettering Cancer Center, New York, NY (United States)

2016-06-15

Purpose: We compare the accuracy of HDR catheter placement for paraspinal lesions using O-arm CBCT imaging combined with StealthStation navigation and traditional fluoroscopically guided catheter placement. Methods: CT and MRI scans were acquired pre-treatment to outline the lesions and design treatment plans (pre-plans) to meet dosimetric constrains. The pre-planned catheter trajectories were transferred into the StealthStation Navigation system prior to the surgery. The StealthStation is an infra red (IR) optical navigation system used for guidance of surgical instruments. An intraoperative CBCT scan (O-arm) was acquired with reference IR optical fiducials anchored onto the patient and registered with the preplan image study to guide surgical instruments in relation to the patients’ anatomy and to place the brachytherapy catheters along the pre-planned trajectories. The final treatment plan was generated based on a 2nd intraoperative CBCT scan reflecting achieved implant geometry. The 2nd CBCT was later registered with the initial CT scan to compare the preplanned dwell positions with actual dwell positions (catheter placements). Similar workflow was used in placement of 8 catheters (1 patient) without navigation, but under fluoroscopy guidance in an interventional radiology suite. Results: A total of 18 catheters (3 patients) were placed using navigation assisted surgery. Average displacement of 0.66 cm (STD=0.37cm) was observed between the pre-plan source positions and actual source positions in the 3 dimensional space. This translates into an average 0.38 cm positioning error in one direction including registration errors, digitization errors, and the surgeons ability to follow the planned trajectory. In comparison, average displacement of non-navigated catheters was 0.50 cm (STD=0.22cm). Conclusion: Spinal lesion HDR brachytherapy planning is a difficult task. Catheter placement has a direct impact on target coverage and dose to critical structures. While

Robot-Assisted Free Flap in Head and Neck Reconstruction

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Han Gyeol Song

2013-07-01

Full Text Available BackgroundRobots have allowed head and neck surgeons to extirpate oropharyngeal tumors safely without the need for lip-split incision or mandibulotomy. Using robots in oropharyngeal reconstruction is new but essential for oropharyngeal defects that result from robotic tumor excision. We report our experience with robotic free-flap reconstruction of head and neck defects to exemplify the necessity for robotic reconstruction.MethodsWe investigated head and neck cancer patients who underwent ablation surgery and free-flap reconstruction by robot. Between July 1, 2011 and March 31, 2012, 5 cases were performed and patient demographics, location of tumor, pathologic stage, reconstruction methods, flap size, recipient vessel, necessary pedicle length, and operation time were investigated.ResultsAmong five free-flap reconstructions, four were radial forearm free flaps and one was an anterolateral thigh free-flap. Four flaps used the superior thyroid artery and one flap used a facial artery as the recipient vessel. The average pedicle length was 8.8 cm. Flap insetting and microanastomosis were achieved using a specially manufactured robotic instrument. The total operation time was 1,041.0 minutes (range, 814 to 1,132 minutes, and complications including flap necrosis, hematoma, and wound dehiscence did not occur.ConclusionsThis study demonstrates the clinically applicable use of robots in oropharyngeal reconstruction, especially using a free flap. A robot can assist the operator in insetting the flap at a deep portion of the oropharynx without the need to perform a traditional mandibulotomy. Robot-assisted reconstruction may substitute for existing surgical methods and is accepted as the most up-to-date method.

Adynamic Graciloplasty With a Pedicled Gracilis Muscle Flap Wrapped Around Bulbar Urethra for Treatment of Male Acquired Urinary Incontinence.

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Guo, Hailin; Sa, Yinglong; Xu, Yuemin; Wang, Lin; Fei, Xiaofang

2016-05-01

To evaluate the efficacy of adynamic gracilis urethral myoplasty with a pedicled gracilis muscle flap wrapped around bulbar urethra for treatment of male acquired urinary incontinence. Twenty-four patients with acquired urinary incontinence (8 after radical prostatectomy, 7 after transurethral resection of the prostate, and 9 after posterior urethroplasty) were included in our study. Eighteen of these patients (75.0%) had mild to moderate urinary incontinence, and 6 (25.0%) had severe urinary incontinence. All patients received adynamic gracilis urethral myoplasty with a pedicled gracilis muscle flap wrapped around bulbar urethra and had a close follow-up. The mean postoperative maximum urethral pressure after the gracilis muscle wrapped around bulbar urethra was significantly higher than that of the preoperative measurements (P urethra can raise the urethral pressure. Adynamic graciloplasty with a pedicled gracilis muscle flap wrapped around bulbar urethra is a safe and effective surgical option in the treatment of male patients with mild to moderate incontinence, but is not suitable for severe incontinence. Copyright © 2016 Elsevier Inc. All rights reserved.

Closed reduction, internal fixation with quadratus femoris muscle pedicle bone grafting in displaced femoral neck fracture

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Chaudhuri Sibaji

2008-01-01

Full Text Available Background: Management of femoral neck fracture is still considered as an unsolved problem. It is more evident in displaced fractures where this fracture is considered as some sort of vascular insult to the head of the femur. We have used closed reduction, internal fixation and quadratus femoris muscle pedicle bone grafting in fresh displaced femoral neck fractures. Materials and Methods: From April 1996 to December 2004 we operated 73 consecutive patients of displaced femoral neck fracture in the age group of 24 to 81 years, mean age being 54.6 years. The patients were operated within one week of injury, the mean delay being 3.6 days. Closed reduction internal fixation along with quadratus femoris muscle pedicle bone grafting was done in all cases. They were followed up for an average period of 5.6 years (range 2-11 years. Results: Results were assessed according to modified Harris Hip Scoring system and found to be excellent in 53, good in 12, fair in six and poor in two patients. Bony union occurred in 68 cases, no patient developed avascular necrosis (AVN till date. Conclusion: For fresh displaced femoral neck fracture in physiologically active patients closed reduction, internal fixation and quadratus femoris muscle pedicle bone grafting is a suitable option to secure union and prevent development of AVN.

Image-guided navigation system for placing dental implants.

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Casap, Nardy; Wexler, Alon; Lustmann, Joshua

2004-10-01

Navigation-guided surgery has recently been introduced into various surgical disciplines, including oral and maxillofacial surgery. Since the advent of dental implants, dental computed tomography (CT) scans have been used as a diagnostic tool for preoperative planning, but not as part of the surgical phase. This article explains the principles of computer-assisted surgery and describes the use of a computer-guided navigation system in dental implantology. The system uses preoperative dental CT scans for planning and as an integral part of the surgical procedure. This system allows continuous intraoperative coordination of the implantation phase with the preoperative plan, optimizing the accuracy of implant surgery. Deviations from the planned location of the implants are minimal. Several cases are discussed.

Blood flow autoregulation in pedicled flaps

DEFF Research Database (Denmark)

Bonde, Christian T; Holstein-Rathlou, Niels-Henrik; Elberg, Jens J

2009-01-01

was to evaluate if, and to what extent, a tissue flap could compensate a reduction in blood flow due to an acute constriction of the feed artery. Further, we wanted to examine the possible role of smooth muscle L-type calcium channels in the autoregulatory mechanism by pharmacological intervention with the L......, the flow in the pedicle was reduced and the flow was recorded. RESULTS: The flaps showed a strong autoregulatory response with complete compensation for flow reductions of up to 70-80%. Infusion of nimodipine caused a 28+/-10% increase in blood flow and removed the autoregulation. Papaverine caused...... a further increase in blood flow by 61+/-19%. The time control experiments proved that the experimental procedure was reproducible and stable over time. CONCLUSIONS: A tissue flap can nearly completely compensate for repeated flow reductions of up to 70-80%. This is due to a decrease in the peripheral...

Renal artery aneurysm in hand-assisted laparoscopic donor nephrectomy: case report.

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Maciel, R F; Branco, A J; Branco, A W; Guterres, J C; Silva, A E; Ramos, L B; Rost, C; Vieira, C A; Cicogna, P E S; Daudt, C A; Deboni, L M; Vieira, M A; Luz, H A; Vieira, J A

2003-12-01

We report a living donor who underwent laparoscopic nephrectomy using a hand-assisted device (HALD). At preoperative arteriography the donor showed a renal artery aneurysm. The patient was a 37-year-old female, 166 cm height, white, weighing 87 kg, HLA identical to the recipient. HALD was indicated due to the better visualization of renal pedicle and greater security in an obese patient. Renal artery aneurysm is a rare condition, with many possible complications. The method proved to be adequate and safe for donor nephrectomy, despite a renal artery aneurysm.

Spatial navigation by congenitally blind individuals.

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Schinazi, Victor R; Thrash, Tyler; Chebat, Daniel-Robert

2016-01-01

Spatial navigation in the absence of vision has been investigated from a variety of perspectives and disciplines. These different approaches have progressed our understanding of spatial knowledge acquisition by blind individuals, including their abilities, strategies, and corresponding mental representations. In this review, we propose a framework for investigating differences in spatial knowledge acquisition by blind and sighted people consisting of three longitudinal models (i.e., convergent, cumulative, and persistent). Recent advances in neuroscience and technological devices have provided novel insights into the different neural mechanisms underlying spatial navigation by blind and sighted people and the potential for functional reorganization. Despite these advances, there is still a lack of consensus regarding the extent to which locomotion and wayfinding depend on amodal spatial representations. This challenge largely stems from methodological limitations such as heterogeneity in the blind population and terminological ambiguity related to the concept of cognitive maps. Coupled with an over-reliance on potential technological solutions, the field has diffused into theoretical and applied branches that do not always communicate. Here, we review research on navigation by congenitally blind individuals with an emphasis on behavioral and neuroscientific evidence, as well as the potential of technological assistance. Throughout the article, we emphasize the need to disentangle strategy choice and performance when discussing the navigation abilities of the blind population. For further resources related to this article, please visit the WIREs website. © 2015 The Authors. WIREs Cognitive Science published by Wiley Periodicals, Inc.

Minimal access direct spondylolysis repair using a pedicle screw-rod system: a case series

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Mohi Eldin Mohamed

2012-11-01

Full Text Available Abstract Introduction Symptomatic spondylolysis is always challenging to treat because the pars defect causing the instability needs to be stabilized while segmental fusion needs to be avoided. Direct repair of the pars defect is ideal in cases of spondylolysis in which posterior decompression is not necessary. We report clinical results using segmental pedicle-screw-rod fixation with bone grafting in patients with symptomatic spondylolysis, a modification of a technique first reported by Tokuhashi and Matsuzaki in 1996. We also describe the surgical technique, assess the fusion and analyze the outcomes of patients. Case presentation At Cairo University Hospital, eight out of twelve Egyptian patients’ acute pars fractures healed after conservative management. Of those, two young male patients underwent an operative procedure for chronic low back pain secondary to pars defect. Case one was a 25-year-old Egyptian man who presented with a one-year history of axial low back pain, not radiating to the lower limbs, after falling from height. Case two was a 29-year-old Egyptian man who presented with a one-year history of axial low back pain and a one-year history of mild claudication and infrequent radiation to the leg, never below the knee. Utilizing a standardized mini-access fluoroscopically-guided surgical protocol, fixation was established with two titanium pedicle screws place into both pedicles, at the same level as the pars defect, without violating the facet joint. The cleaned pars defect was grafted; a curved titanium rod was then passed under the base of the spinous process of the affected vertebra, bridging the loose fragment, and attached to the pedicle screw heads, to uplift the spinal process, followed by compression of the defect. The patients were discharged three days after the procedure, with successful fusion at one-year follow-up. No rod breakage or implant-related complications were reported. Conclusions Where there is no

Decision making in double-pedicled DIEP and SIEA abdominal free flap breast reconstructions: An algorithmic approach and comprehensive classification.

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Charles M Malata

2015-10-01

Full Text Available Introduction: The deep inferior epigastric artery perforator (DIEP free flap is the gold standard for autologous breast reconstruction. However, using a single vascular pedicle may not yield sufficient tissue in patients with midline scars or insufficient lower abdominal pannus. Double-pedicled free flaps overcome this problem using different vascular arrangements to harvest the entire lower abdominal flap. The literature is, however, sparse regarding technique selection. We therefore reviewed our experience in order to formulate an algorithm and comprehensive classification for this purpose. Methods: All patients undergoing unilateral double-pedicled abdominal perforator free flap breast reconstruction (AFFBR by a single surgeon (CMM over 40 months were reviewed from a prospectively collected database. Results: Of the 112 consecutive breast free flaps performed, 25 (22% utilised two vascular pedicles. The mean patient age was 45 years (range=27-54. All flaps but one (which used the thoracodorsal system were anastomosed to the internal mammary vessels using the rib-preservation technique. The surgical duration was 656 minutes (range=468-690 mins. The median flap weight was 618g (range=432-1275g and the mastectomy weight was 445g (range=220-896g. All flaps were successful and only three patients requested minor liposuction to reduce and reshape their reconstructed breasts.Conclusion: Bipedicled free abdominal perforator flaps, employed in a fifth of all our AFFBRs, are a reliable and safe option for unilateral breast reconstruction. They, however, necessitate clear indications to justify the additional technical complexity and surgical duration. Our algorithm and comprehensive classification facilitate technique selection for the anastomotic permutations and successful execution of these operations.

A case of incisional hernia repair using Composix mesh prosthesis after antethoracic pedicled jejunal flap reconstruction following an esophagectomy.

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Yasuda, Atsushi; Yasuda, Takushi; Kato, Hiroaki; Iwama, Mitsuru; Shiraishi, Osamu; Hiraki, Yoko; Tanaka, Yumiko; Shinkai, Masayuki; Imano, Motohiro; Kimura, Yutaka; Imamoto, Haruhiko

2017-12-01

An incisional hernia in a case of antethoracic pedicled jejunal flap esophageal reconstruction after esophagectomy is a very rare occurrence, and this hernia was distinctive in that the reconstructed jejunum had passed through the hernial orifice; a standard surgical treatment for such a presentation has not been established. Herein, we describe a case of repair using mesh prosthesis for an atypical and distinctive incisional hernia after antethoracic pedicled jejunal flap esophageal reconstruction. A 77-year-old woman with a history of subtotal esophagectomy who had undergone antethoracic pedicled jejunal flap reconstruction complained of epigastric prominence and discomfort without pain. On examination, she had an abdominal protrusion between the xiphoid process and the umbilicus that contained the small bowel. Computed tomography showed that the fenestration of the abdominal wall that was intentionally created for jejunum pull-up was dehisced in a region measuring 9 × 15 cm and the small intestine protruded through it into the subcutaneous space without strangulation. Because the hernial orifice was too large and the reconstructed jejunum was passing through the hernial orifice in this case, we applied a parastomal hernia repair method that was modified from the inguinal hernia repair using the Lichtenstein technique. After 3 years and 5 months following surgery, the patient has recovered without hernia recurrence or other complications. We consider this to be the first case of repair using Composix mesh prosthesis for repair of an atypical and distinctive incisional hernia after an antethoracic pedicled jejunal flap reconstruction. This method seems to be useful and could potentially be widely adopted as the surgical treatment for this condition.

[Clinical efficacy of unilateral percutaneous transfacet screws combined with contralateral pedicle screw versus bilateral pedicle screws fixation in the treatment of the degenerative lumbar disease].

Science.gov (United States)

Hao, Rong-Xue; Zhou, Hui; Pan, Hao; Yue, Jun; Chen, Hui-Guo; Yang, He-Jie; Jia, Gao-Yong; Wang, Dong; Lin, Yan; Xu, Hua-Zi

2017-09-25

To investigate the surgical outcome of unilateral pedicle screw(UPS) after TLIF technique combined with contralateral percutaneous transfacet screw(PTS) fixation vs bilateral pedicle screws(BPS) fixation in treatment of degenerative lumbar disease. From January 2009 to June 2012, 46 patients with degenerative lumbar diseases, including 30 males and 16 females with an average age of 51.5 years old, who were divided into two groups according to different fixation methods. Twenty-two cases underwent UPS after TLIF technique combined with contralateral PTS fixation (group A), while the others underwent BPS fixation(group B). The relative data were analyzed, such as blood loss volume, operative time, fusion rate, ODI score, JOA score and so on. All the patients were followed up for 1 to 3 years with an average of 22 months. Except one case of each group was uncertainty fusion, the rest have obtained bony fusion, and the fusion rates in group A and B were 95.5% and 95.8%, respectively. No displacement and breakage of screw were found during follow-up. Operative time and blood loss volume in group A were better than of group B( P 0.05). Two approaches had similar clinical outcomes for degenerative lumbar disease with no severe instability. Compared with BPS fixation, the UPS after TLIF technique and contralateral PTS fixation has the advantages of less trauma, shorter operative time and less blood loss, and it is a safe and feasible surgical technique.

Navigated versus conventional total knee arthroplasty: A prospective study at three years follow-up.

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Martín-Hernández, C; Sanz-Sainz, M; Revenga-Giertych, C; Hernández-Vaquero, D; Fernández-Carreira, J M; Albareda-Albareda, J; Castillo-Palacios, A; Ranera-Garcia, M

2018-03-28

Computer-assisted surgery application in total knee arthroplasty (TKA) has shown more accurate implant alignment compared with conventional instrumentation and is associated with more homogeneous alignment results. Although longer implant survival and superior clinical outcomes should be expected from navigated TKA, currently available evidence does not support this hypothesis. The aim of this study was to compare navigated TKA with conventional TKA regarding clinical and radiological outcomes after a 3-year follow-up under the hypothesis that navigated TKA would provide better outcomes than conventional TKA. In a prospective multicentre study, 119 patients underwent navigated TKA and 80 patients received conventional instrumentation. Patients were evaluated at the baseline and at postoperative months 3, 12, 24, and 36. Analysis included the American Knee Society Score (KSS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Short Form-12 (SF12) Health Survey, and radiographic assessment. All clinical scores improved significantly for all patients during the follow-up but were significantly better in the navigation group. The percentage of patients showing a mechanical axis between 3° of varus and 3° of valgus was significantly higher in the ATR group (93%) than in the conventional TKA group (71%) (P<.01). The use of computer-assisted surgery in TKA provides more accurate mechanical alignment and superior short-term functional outcomes compared to conventional TKA. Copyright © 2018 SECOT. Publicado por Elsevier España, S.L.U. All rights reserved.

Florida coastal Aids to Navigation GIS data in 2001 (NCEI Accession 0000599)

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National Oceanic and Atmospheric Administration, Department of Commerce — The term Aids to Navigation (ATONS or AIDS) refers to a device outside of a vessel used to assist mariners in determining their position or safe course, or to warn...

Does intraoperative navigation improve the accuracy of mandibular angle osteotomy: Comparison between augmented reality navigation, individualised templates and free-hand techniques.

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Zhu, Ming; Liu, Fei; Zhou, Chaozheng; Lin, Li; Zhang, Yan; Chai, Gang; Xie, Le; Qi, Fazhi; Li, Qingfeng

2018-04-11

Augmented reality (AR)-based navigation surgery has evolved to be an advanced assisted technology. The aim of this study is to manifest the accuracy of AR navigation for the intraoperative mandibular angle osteotomy by comparing the navigation with other interventional techniques. A retrospective study was conducted with 93 post-surgical patients with mandibular angle hypertrophy admitted at our plastic and reconstructive surgery department between September 2011 and June 2016. Thirty-one patients received osteotomy conducted using a navigation system based on augmented reality (AR group), 28 patients received osteotomy conducted using individualised templates (IT group) and the remaining 34 patients received osteotomy performed by free hand (free-hand group). The post-operative computed tomography (CT) images were reviewed and analysed by comparing with pre-surgical planning generated by three-dimensional (3D) software. The preparation time, cutting time, whole operating time and discrepancy in osteotomy lines were measured. The preparation time was much shorter for the free-hand group than that for the AR group and the IT group (P  0.05). In addition, the discrepancy in osteotomy lines was lower for the AR group and in the IT group than for the free-hand group (P < 0.01). The navigation system based on AR has a higher accuracy, more reliability and better user friendliness for some particular clinical procedures than for other techniques, which has a promising clinical prospect. Copyright © 2018. Published by Elsevier Ltd.

Real-time fluoroscopic needle guidance in the interventional radiology suite using navigational software for percutaneous bone biopsies in children

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Shellikeri, Sphoorti; Srinivasan, Abhay; Krishnamurthy, Ganesh; Vatsky, Seth; Zhu, Xiaowei; Keller, Marc S.; Cahill, Anne Marie [The Children' s Hospital of Philadelphia, Department of Radiology, Philadelphia, PA (United States); Setser, Randolph M. [Siemens Medical Solutions USA, Inc., Hoffman Estates, IL (United States); Hwang, Tiffany J. [University of Southern California, Keck School of Medicine, Los Angeles, CA (United States); Girard, Erin [Siemens Medical Solutions USA, Inc., Princeton, NJ (United States)

2017-07-15

Navigational software provides real-time fluoroscopic needle guidance for percutaneous procedures in the Interventional Radiology (IR) suite. We describe our experience with navigational software for pediatric percutaneous bone biopsies in the IR suite and compare technical success, diagnostic accuracy, radiation dose and procedure time with that of CT-guided biopsies. Pediatric bone biopsies performed using navigational software (Syngo iGuide, Siemens Healthcare) from 2011 to 2016 were prospectively included and anatomically matched CT-guided bone biopsies from 2008 to 2016 were retrospectively reviewed with institutional review board approval. C-arm CT protocols used for navigational software-assisted cases included institution-developed low-dose (0.1/0.17 μGy/projection), regular-dose (0.36 μGy/projection), or a combination of low-dose/regular-dose protocols. Estimated effective radiation dose and procedure times were compared between software-assisted and CT-guided biopsies. Twenty-six patients (15 male; mean age: 10 years) underwent software-assisted biopsies (15 pelvic, 7 lumbar and 4 lower extremity) and 33 patients (13 male; mean age: 9 years) underwent CT-guided biopsies (22 pelvic, 7 lumbar and 4 lower extremity). Both modality biopsies resulted in a 100% technical success rate. Twenty-five of 26 (96%) software-assisted and 29/33 (88%) CT-guided biopsies were diagnostic. Overall, the effective radiation dose was significantly lower in software-assisted than CT-guided cases (3.0±3.4 vs. 6.6±7.7 mSv, P=0.02). The effective dose difference was most dramatic in software-assisted cases using low-dose C-arm CT (1.2±1.8 vs. 6.6±7.7 mSv, P=0.001) or combined low-dose/regular-dose C-arm CT (1.9±2.4 vs. 6.6±7.7 mSv, P=0.04), whereas effective dose was comparable in software-assisted cases using regular-dose C-arm CT (6.0±3.5 vs. 6.6±7.7 mSv, P=0.7). Mean procedure time was significantly lower for software-assisted cases (91±54 vs. 141±68 min, P=0

Kilohoku Ho`okele Wa`a : Astronomy of the Hawaiian Navigators

Science.gov (United States)

Slater, Stephanie; Slater, Timothy F.; Baybayan, Kalepa C.

2016-01-01

This poster provides an introduction to the astronomy of the Hawaiian wayfinders, Kilohoku Ho`okele Wa`a. Rooted in a legacy of navigation across the Polynesian triangle, wayfinding astronomy has been part of a suite of skills that allows navigators to deliberately hop between the small islands of the Pacific, for thousands of years. Forty years ago, in one manifestation of the Hawaiian Renaissance, our teachers demonstrated that ancient Hawaiians were capable of traversing the wide Pacific to settle and trade on islands separated by thousands of miles. Today those same mentors train a new generation of navigators, making Hawaiian voyaging a living, evolving, sustainable endeavor. This poster presents two components of astronomical knowledge that all crewmen, but particularly those in training to become navigators, learn early in their training. Na Ohana Hoku, the Hawaiian Star Families constitute the basic units of the Hawaiian sky. In contrast to the Western system of 88 constellations, Na Ohana Hoku divides the sky into four sections that each run from the northern to the southern poles. This configuration reduces cognitive load, allowing the navigator to preserve working memory for other complex tasks. In addition, these configurations of stars support the navigator in finding and generatively using hundreds of individual, and navigationally important pairs of stars. The Hawaiian Star Compass divides the celestial sphere into a directional system that uses 32 rather than 8 cardinal points. Within the tropics, the rising and setting of celestial objects are consistent within the Hawaiian Star Compass, providing for extremely reliable direction finding. Together, Na Ohana Hoku and the Hawaiian Star Compass provide the tropical navigator with astronomical assistance that is not available to, and would have been unknown to Western navigators trained at higher latitudes.

Creation of false pedicles and a neo-pelvis for lumbopelvic reconstruction following en bloc resection of an iliosacral chondrosarcoma with lumbar spine extension: technical note.

Science.gov (United States)

Mendel, Ehud; Nathoo, Narendra; Scharschmidt, Thomas; Schmidt, Carl; Boehmler, James; Mayerson, Joel L

2014-03-01

En bloc resection with negative tumor margins remains the principal treatment option for control or cure of primary pelvic chondrosarcomas, as current adjuvant therapies remain ineffective. Iliosacral chondrosarcomas with involvement of the sciatic notch are sufficiently challenging tumors. However, when there is concomitant lumbar extension requiring resection of the pedicles to maintain negative surgical margins, transpedicular screw fixation is not possible, making reconstruction of the lumbopelvic junction extremely challenging. A patient with an iliosacral chondrosarcoma with lumbar spine extension is presented in this report to illustrate a novel lumbopelvic spinal construct. Following combined external pelvectomy and hemisacrectomy with contralateral L3-5 hemilaminectomy and ipsilateral pediculotomy, bicortical transvertebral body screws were substituted for the missing pedicles, resulting in the creation of "false pedicles," which were further supplemented with an autologous vascularized fibular strut graft from the amputated lower limb and applied to the lateral aspect of the vertebral bodies. The creation of false pedicles allowed for a robust reconstruction of the lumbopelvic junction, including maintaining pelvic ring integrity with a "neo-pelvis", creating a functional load-bearing construct adequate for early mobilization and ambulation. The biomechanical dynamics of this unique construct are also discussed.

Navigation system for robot-assisted intra-articular lower-limb fracture surgery.

Science.gov (United States)

Dagnino, Giulio; Georgilas, Ioannis; Köhler, Paul; Morad, Samir; Atkins, Roger; Dogramadzi, Sanja

2016-10-01

In the surgical treatment for lower-leg intra-articular fractures, the fragments have to be positioned and aligned to reconstruct the fractured bone as precisely as possible, to allow the joint to function correctly again. Standard procedures use 2D radiographs to estimate the desired reduction position of bone fragments. However, optimal correction in a 3D space requires 3D imaging. This paper introduces a new navigation system that uses pre-operative planning based on 3D CT data and intra-operative 3D guidance to virtually reduce lower-limb intra-articular fractures. Physical reduction in the fractures is then performed by our robotic system based on the virtual reduction. 3D models of bone fragments are segmented from CT scan. Fragments are pre-operatively visualized on the screen and virtually manipulated by the surgeon through a dedicated GUI to achieve the virtual reduction in the fracture. Intra-operatively, the actual position of the bone fragments is provided by an optical tracker enabling real-time 3D guidance. The motion commands for the robot connected to the bone fragment are generated, and the fracture physically reduced based on the surgeon's virtual reduction. To test the system, four femur models were fractured to obtain four different distal femur fracture types. Each one of them was subsequently reduced 20 times by a surgeon using our system. The navigation system allowed an orthopaedic surgeon to virtually reduce the fracture with a maximum residual positioning error of [Formula: see text] (translational) and [Formula: see text] (rotational). Correspondent physical reductions resulted in an accuracy of 1.03 ± 0.2 mm and [Formula: see text], when the robot reduced the fracture. Experimental outcome demonstrates the accuracy and effectiveness of the proposed navigation system, presenting a fracture reduction accuracy of about 1 mm and [Formula: see text], and meeting the clinical requirements for distal femur fracture reduction procedures.

Three-dimensional navigation is more accurate than two-dimensional navigation or conventional fluoroscopy for percutaneous sacroiliac screw fixation in the dysmorphic sacrum: a randomized multicenter study.

Science.gov (United States)

Matityahu, Amir; Kahler, David; Krettek, Christian; Stöckle, Ulrich; Grutzner, Paul Alfred; Messmer, Peter; Ljungqvist, Jan; Gebhard, Florian

2014-12-01

To evaluate the accuracy of computer-assisted sacral screw fixation compared with conventional techniques in the dysmorphic versus normal sacrum. Review of a previous study database. Database of a multinational study with 9 participating trauma centers. The reviewed group included 130 patients, 72 from the navigated group and 58 from the conventional group. Of these, 109 were in the nondysmorphic group and 21 in the dysmorphic group. Placement of sacroiliac (SI) screws was performed using standard fluoroscopy for the conventional group and BrainLAB navigation software with either 2-dimensional or 3-dimensional (3D) navigation for the navigated group. Accuracy of SI screw placement by 2-dimensional and 3D navigation versus conventional fluoroscopy in dysmorphic and nondysmorphic patients, as evaluated by 6 observers using postoperative computerized tomography imaging at least 1 year after initial surgery. Intraobserver agreement was also evaluated. There were 11.9% (13/109) of patients with misplaced screws in the nondysmorphic group and 28.6% (6/21) of patients with misplaced screws in the dysmorphic group, none of which were in the 3D navigation group. Raw agreement between the 6 observers regarding misplaced screws was 32%. However, the percent overall agreement was 69.0% (kappa = 0.38, P dysmorphic proximal sacral segment. We recommend the use of 3D navigation, where available, for insertion of SI screws in patients with normal and dysmorphic proximal sacral segments. Therapeutic level I.

[Tibia reconstruction using cross-leg pedicled fibular flaps: report of two cases].

Science.gov (United States)

Molski, M

2000-01-01

The paper presents the results of treatment of two children with cross-leg pedicle fibular flaps. A boy (10 years old) was operated because of an extensive defect of the proximal tibial shaft (15 cm) and soft tissue deficit due to osteosarcoma. He had been previously operated several times: tumor resection with chemiotherapy, bone reconstruction using allografts and two other procedures because of inflammatory complications. The second case was a 9-year old girl who underwent an extensive excision of congenital pseudoarthrosis of the tibia due to neurofibroma and reconstruction of the further fragment of the tibia. Vascularized fibula was nailed deep into the tibial shaft, beyond the previously implanted metal elements. This allowed to maintain a correct axis of the limb, a firm stabilization of the transplant and probably evoked a quick periosteal reaction of the tibia. Plaster of Paris was used to immobilize the limb. Postoperative course showed no complications. The flap pedicle was cut off after 3-4 weeks. Progressive bone healing followed by bony hypertrophy was observed after 8 weeks. The children were able to fully load the operated extremities and ambulate without crutches (the boys 12 months post-surgery and the girl 6 months post-surgery).

Localization and characterization of STRO-1 cells in the deer pedicle and regenerating antler.

Directory of Open Access Journals (Sweden)

Hans J Rolf

2008-04-01

Full Text Available The annual regeneration of deer antlers is a unique developmental event in mammals, which as a rule possess only a very limited capacity to regenerate lost appendages. Studying antler regeneration can therefore provide a deeper insight into the mechanisms that prevent limb regeneration in humans and other mammals, and, with regard to medical treatments, may possibly even show ways how to overcome these limitations. Traditionally, antler regeneration has been characterized as a process involving the formation of a blastema from de-differentiated cells. More recently it has, however, been hypothesized that antler regeneration is a stem cell-based process. Thus far, direct evidence for the presence of stem cells in primary or regenerating antlers was lacking. Here we demonstrate the presence of cells positive for the mesenchymal stem cell marker STRO-1 in the chondrogenic growth zone and the perivascular tissue of the cartilaginous zone in primary and regenerating antlers as well as in the pedicle of fallow deer (Dama dama. In addition, cells positive for the stem cell/progenitor cell markers STRO-1, CD133 and CD271 (LNGFR were isolated from the growth zones of regenerating fallow deer antlers as well as the pedicle periosteum and cultivated for extended periods of time. We found evidence that STRO-1(+ cells isolated from the different locations are able to differentiate in vitro along the osteogenic and adipogenic lineages. Our results support the view that the annual process of antler regeneration might depend on the periodic activation of mesenchymal progenitor cells located in the pedicle periosteum. The findings of the present study indicate that not only limited tissue regeneration, but also extensive appendage regeneration in a postnatal mammal can occur as a stem cell-based process.

Virtual Planning and Intraoperative Navigation in Craniomaxillofacial Surgery

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Jorge Guiñales

2017-08-01

Full Text Available Surgery planning assisted by computer represents one important example of the collaboration between surgeons and engineers. Virtual planning allows surgeons to pre-do the surgery by working over a virtual 3D model of the patient obtained through a computer tomography. Through surgical navigation, surgeons are helped while working with deep structures and can check if they are following accurately the surgical plan. These assistive tools are crucial in the field of facial reconstructive surgery. This paper describes two cases, one related to orbital fractures and another one related to oncological patients, showing the advantages that these tools provide, specifically when used for craniomaxillofacial surgery.

Reconstruction of large upper eyelid defects with a free tarsal plate graft and a myocutaneous pedicle flap plus a free skin graft.

Science.gov (United States)

Toft, Peter B

2016-01-01

To review and present the results of a one-step method employing a free tarsal plate graft and a myocutaneous pedicle flap plus a free skin graft for reconstruction of large upper eyelid defects after tumour surgery. This was a retrospective case-series of 8 patients who underwent reconstruction of the upper eyelid after tumour removal. The horizontal defect involved 50-75% of the lid (3 pts.), more than 75% (3 pts.), and more than 75% plus the lateral canthus (2 pts.). The posterior lamella was reconstructed with contralateral upper eyelid tarsal plate. The anterior lamella was reconstructed with a laterally based myocutaneous pedicle flap in 7 patients, leaving a raw surface under the brow which was covered with a free skin graft. In 1 patient with little skin left under the brow, the anterior lamella was reconstructed with a bi-pedicle orbicularis muscle flap together with a free skin graft. All patients healed without necrosis, did not suffer from lagophthalmos, achieved reasonable cosmesis, and did not need lubricants. In one patient, a contact lens was necessary for three weeks because of corneal erosion. One patient still needs a contact lens 3 months after excision to avoid eye discomfort. Large upper eyelid defects can be reconstructed with a free tarsal plate graft and a laterally based myocutaneous pedicle flap in combination with a free skin graft. Two-step procedures can probably be avoided in most cases.

Current use of navigation system in ACL surgery: a historical review.

Science.gov (United States)

Zaffagnini, S; Urrizola, F; Signorelli, C; Grassi, A; Di Sarsina, T Roberti; Lucidi, G A; Marcheggiani Muccioli, G M; Bonanzinga, T; Marcacci, M

2016-11-01

The present review aims to analyse the available literature regarding the use of navigation systems in ACL reconstructive surgery underling the evolution during the years. A research of indexed scientific papers was performed on PubMed and Cochrane Library database. The research was performed in December 2015 with no publication year restriction. Only English-written papers and related to the terms ACL, NAVIGATION, CAOS and CAS were considered. Two reviewers independently selected only those manuscripts that presented at least the application of navigation system for ACL reconstructive surgery. One hundred and forty-six of 394 articles were finally selected. In this analysis, it was possible to review the main uses of navigation system in ACL surgery including tunnel positioning for primary and revision surgery and kinematic assessment of knee laxity before and after different surgical procedures. In the early years, until 2006, navigation system was mainly used to improve tunnel positioning, but since the last decade, this tool has been principally used for kinematics evaluation. Increased accuracy of tunnel placement was observed using navigation surgery, especially, regarding femoral, 42 of 146 articles used navigation to guide tunnel positioning. During the following years, 82 of 146 articles have used navigation system to evaluate intraoperative knee kinematic. In particular, the importance of controlling rotatory laxity to achieve better surgical outcomes has been underlined. Several applications have been described and despite the contribution of navigation systems, its potential uses and theoretical advantages, there are still controversies about its clinical benefit. The present papers summarize the most relevant studies that have used navigation system in ACL reconstruction. In particular, the analysis identified four main applications of the navigation systems during ACL reconstructive surgery have been identified: (1) technical assistance for tunnel

Analysis of MRI signal changes in the adjacent pedicle of adolescent patients with fresh lumbar spondylolysis.

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Goda, Yuichiro; Sakai, Toshinori; Sakamaki, Tadanori; Takata, Yoichiro; Higashino, Kosaku; Sairyo, Koichi

2014-09-01

The purpose of this study is to investigate a discrepancy between MRI and computed tomography (CT) findings in the spinal level distribution of spondylolysis. Recent advances in MRI have led to the early diagnosis of spondylolysis. Therefore, bony healing can be expected before the condition has a chance to worsen. In this study, we used MRI to examine the changes in spinal level signals in the pedicles adjacent to the pars interarticularis in adolescents with fresh lumbar spondylolysis. We then compared spinal level distribution of spondylolysis with that of previous results obtained by multidetector CT. The study included 98 adolescent patients (31 women and 67 men; mean age, 13.6 years; age range, 9-18 years) with fresh lumbar spondylolysis who showed MRI signal changes in the adjacent pedicle. An MRI signal change was defined as a high signal change on fat-suppressed imaging. MRI signal changes were detected in 150 adjacent pedicles of 101 vertebrae. Of these vertebrae, MRI signal changes in only 67 (66.3%) corresponded to L5, while changes in 34 (33.7%) corresponded to L3 or L4. In our follow-up study, the bone-healing rate with no vertebral defect was 100% at L3, 97.1% at L4, and 84.4% at L5. In addition, 11 of 34 (32.4%) vertebrae with signal changes at L3 or L4 occurred with L5 terminal-stage spondylolysis (no MRI signal change). MRI revealed a higher prevalence of L3 or L4 spondylolysis than observed with CT.

Indications, Outcomes, and Complications of Pedicled Propeller Perforator Flaps for Upper Body Defects: A Systematic Review

Directory of Open Access Journals (Sweden)

Davide Lazzeri

2013-01-01

Full Text Available BackgroundThe aim of this investigation was to systematically review the current literature to provide the best data for indications, outcomes, survival, and complication rates of pedicled propeller perforator flaps for upper body defects.MethodsA comprehensive literature review for articles published from January 1991 to December 2011 was performed using the PubMed, Medline, and Cochrane Databases. Articles without available full-text, single case reports or papers with excessive missing data were excluded. Papers reporting pedicle-perforator (propeller flaps used for lower extremity reconstruction were excluded from meta-analysis.ResultsFrom the initial 1,736 studies our search yielded, 343 studies qualified for the second stage of selection. Of 117 full-text reports screened, 41 studies, met the definitive inclusion and exclusion criteria. Of the selected 41 articles, 26 were case series, original papers or retrospective reviews and were included, whereas 15 were case report papers and therefore were excluded. Two hundred ninety-five propeller flaps were reported to have been used in a total of 283 patients. Indications include repair of trauma-induced injuries, post-trauma revision surgery, cancer resection, chronic infection, pressure sores, and chronic ulcers with a major complication rate (3.3% comparable to that of free flaps. No specific exclusion criteria for the procedure were presented in the studies reviewed.ConclusionsPedicled propeller flaps are a versatile and safe reconstructive option that are easy and quick to raise and that provide unlimited clinical solutions because of the theoretical possibility of harvesting them based on any perforator chosen among those classified in the body.

"Two-step" technique with OsiriXTM to evaluate feasibility of C2 pedicle for surgical fixation

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Luis Miguel Sousa Marques

2016-01-01

Full Text Available Background: Surgical treatment of craniovertebral junction pathology has evolved considerably in recent decades with the implementation of short atlanto-axial fixation techniques, notwhithstanding increasing neurovascular risks. Also, there is strong evidence that fixation of C2 anatomical pedicle has the best biomechanical profile of the entire cervical spine. However, it is often difficult and misleading, to evaluate anatomical bony and vascular anomalies using the three orthogonal planes (axial, coronal, and sagittal of CT. Objectives: The authors describe an innovative and simple technique to evaluate the feasibility of C2 pedicle for surgical screw fixation using preoperative planning with the free DICOM (Digital Imaging and Communications in Medicine software OsiriX TM . Materials and Methods: The authors report the applicatin of this novel technique in 5 cases (3 traumatic, 1 Os Odontoideum, and 1 complex congenital malformation collected from our general case series of the Department in the last 5 years. Results: In this "proof of concept" study, the pre-operative analysis with the "two-step" tecnique was detrimental for choosing the surgical tecnique. Detailed post-operative analysis confirmed correct position of C2 screws without cortical breach. There were no complications or mortality reported. Conclusion: This "two-step" technique is an easy and reliable way to determine the feasibility of C2 pedicle for surgical fixation. The detailed tridimensional radiological preoperative evaluation of craniovertebral junction anatomy is critical to the sucess and safety of this surgeries, and can avoid, to certain degree, expensive intra-operative tridimensional imaging facilities.

Navigation in diagnosis and therapy

International Nuclear Information System (INIS)

Vannier, Michael W.; Haller, John W.

1999-01-01

Image-guided navigation for surgery and other therapeutic interventions has grown in importance in recent years. During image-guided navigation a target is detected, localized and characterized for diagnosis and therapy. Thus, images are used to select, plan, guide and evaluate therapy, thereby reducing invasiveness and improving outcomes. A shift from traditional open surgery to less-invasive image-guided surgery will continue to impact the surgical marketplace. Increases in the speed and capacity of computers and computer networks have enabled image-guided interventions. Key elements in image navigation systems are pre-operative 3D imaging (or real-time image acquisition), a graphical display and interactive input devices, such as surgical instruments with light emitting diodes (LEDs). CT and MRI, 3D imaging devices, are commonplace today and 3D images are useful in complex interventions such as radiation oncology and surgery. For example, integrated surgical imaging workstations can be used for frameless stereotaxy during neurosurgical interventions. In addition, imaging systems are being expanded to include decision aids in diagnosis and treatment. Electronic atlases, such as Voxel Man or others derived from the Visible Human Project, combine a set of image data with non-image knowledge such as anatomic labels. Robot assistants and magnetic guidance technology are being developed for minimally invasive surgery and other therapeutic interventions. Major progress is expected at the interface between the disciplines of radiology and surgery where imaging, intervention and informatics converge

The pedicle screw-rod system is an acceptable method of reconstructive surgery after resection of sacroiliac joint tumours

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Yi-Jun Zhou

2016-03-01

Full Text Available Hemipelvic resections for primary bone tumours require reconstruction to restore weight bearing along anatomic axes. However, reconstruction of the pelvic arch remains a major surgical challenge because of the high rate of associated complications. We used the pedicle screw-rod system to reconstruct the pelvis, and the purpose of this investigation was to assess the oncology, functional outcome and complication rate following this procedure. The purpose of this study was to investigate the operative indications and technique of the pedicle screw-rod system in reconstruction of the stability of the sacroiliac joint after resection of sacroiliac joint tumours. The average MSTS (Musculoskeletal Tumour Society score was 26.5 at either three months after surgery or at the latest follow-up. Seven patients had surgery-related complications, including wound dehiscence in one, infection in two, local necrosis in four (including infection in two, sciatic nerve palsy in one and pubic symphysis subluxation in one. There was no screw loosening or deep vein thrombosis occurring in this series. Using a pedicle screw-rod after resection of a sacroiliac joint tumour is an acceptable method of pelvic reconstruction because of its reduced risk of complications and satisfactory functional outcome, as well as its feasibility of reconstruction for type IV pelvis tumour resection without elaborate preoperative customisation. Level of evidence: Level IV, therapeutic study.

Use of Supplemental Short Pre-Contoured Accessory Rods and Cobalt Chrome Alloy Posterior Rods Reduces Primary Rod Strain and Range of Motion Across the Pedicle Subtraction Osteotomy Level

DEFF Research Database (Denmark)

Hallager, Dennis Winge; Gehrchen, Poul Martin; Dahl, Benny

2016-01-01

and rod strain is necessary to determine the biomechanical efficacy of these techniques. METHODS: Five specimens (T12-S1) underwent PSO at L3 with pedicle screw stabilization at L1-S1. Pedicle subtraction was adjusted to achieve a final lordosis of 70°. Flexion-extension (FE), lateral bending, and axial...

Improving Canada's Marine Navigation System through e-Navigation

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Daniel Breton

2016-06-01

The conclusion proposed is that on-going work with key partners and stakeholders can be used as the primary mechanism to identify e-Navigation related innovation and needs, and to prioritize next steps. Moving forward in Canada, implementation of new e-navigation services will continue to be stakeholder driven, and used to drive improvements to Canada's marine navigation system.

Towards a Sign-Based Indoor Navigation System for People with Visual Impairments.

Science.gov (United States)

Rituerto, Alejandro; Fusco, Giovanni; Coughlan, James M

2016-10-01

Navigation is a challenging task for many travelers with visual impairments. While a variety of GPS-enabled tools can provide wayfinding assistance in outdoor settings, GPS provides no useful localization information indoors. A variety of indoor navigation tools are being developed, but most of them require potentially costly physical infrastructure to be installed and maintained, or else the creation of detailed visual models of the environment. We report development of a new smartphone-based navigation aid, which combines inertial sensing, computer vision and floor plan information to estimate the user's location with no additional physical infrastructure and requiring only the locations of signs relative to the floor plan. A formative study was conducted with three blind volunteer participants demonstrating the feasibility of the approach and highlighting the areas needing improvement.

Outcomes of percutaneous pedicle screw fixation for spinal trauma and tumours.

Science.gov (United States)

Mobbs, Ralph J; Park, Ashley; Maharaj, Monish; Phan, Kevin

2016-01-01

We investigated the clinical and radiological results of percutaneous pedicle screw fixation in the management of spinal trauma and metastatic tumours. A retrospective analysis was performed on a series of 14 patients who were operated on from March 2009 to November 2011 by a single surgeon (RJM). Following a radiological review (CT scan/MRI), six patients underwent short segment fixation, while the remaining underwent long segment fixation. All patients had routine follow-ups at 4, 6, 12months, and annually thereafter. Clinical examinations were conducted preoperatively and postoperatively, and the length of operation, blood loss, and postoperative pain relief were recorded. There was a single patient with an incision site complication. The mean blood loss was 269mL. All of the parameters demonstrated no significant differences between the trauma and the tumour groups (p=0.10). The neurological power scores improved for all patients, with the largest increase being from a score of 2 to 4. At follow-up, the majority of patients had returned to their previous activities and had reduced pain scores. One patient suffered high pain levels from other medical conditions that were not related to the operation. Minimally invasive pedicle screw fixation is a suitable option for patients with spinal tumours and fractures, with acceptable safety and efficacy in this small retrospective patient series. We have seen favourable results in our patients, who have experienced an increased quality of life following their surgery. Copyright © 2015 Elsevier Ltd. All rights reserved.

Navigating on handheld displays: Dynamic versus Static Keyhole Navigation

NARCIS (Netherlands)

Mehra, S.; Werkhoven, P.; Worring, M.

2006-01-01

Handheld displays leave little space for the visualization and navigation of spatial layouts representing rich information spaces. The most common navigation method for handheld displays is static peephole navigation: The peephole is static and we move the spatial layout behind it (scrolling). A

A new method of three-dimensional computer assisted reconstruction of the developing biliary tract.

Science.gov (United States)

Prudhomme, M; Gaubert-Cristol, R; Jaeger, M; De Reffye, P; Godlewski, G

1999-01-01

A three-dimensional (3-D) computer assisted reconstruction of the biliary tract was performed in human and rat embryos at Carnegie stage 23 to describe and compare the biliary structures and to point out the anatomic relations between the structures of the hepatic pedicle. Light micrograph images from consecutive serial sagittal sections (diameter 7 mm) of one human and 16 rat embryos were directly digitalized with a CCD camera. The serial views were aligned automatically by software. The data were analysed following segmentation and thresholding, allowing automatic reconstruction. The main bile ducts ascended in the mesoderm of the hepatoduodenal ligament. The extrahepatic bile ducts: common bile duct (CD), cystic duct and gallbladder in the human, formed a compound system which could not be shown so clearly in histologic sections. The hepato-pancreatic ampulla was studied as visualised through the duodenum. The course of the CD was like a chicane. The gallbladder diameter and length were similar to those of the CD. Computer-assisted reconstruction permitted easy acquisition of the data by direct examination of the sections through the microscope. This method showed the relationships between the different structures of the hepatic pedicle and allowed estimation of the volume of the bile duct. These findings were not obvious in two-dimensional (2-D) views from histologic sections. Each embryonic stage could be rebuilt in 3-D, which could introduce the time as a fourth dimension, fundamental for the study of organogenesis.

Navigating the National Qualifications Framework (NQF): The Role of Career Guidance

Science.gov (United States)

Walters, S.; Watts, A. G.; Flederman, P.

2009-01-01

The South African Qualifications Authority (SAQA) recently commissioned a review of the career development field in South Africa. The review was designed to clarify what SAQA's role might be in assisting learners throughout life to navigate their ways through the complex array of education, training and work opportunities (including, but not…

[Misinterpretation of the anteversion in computer-assisted acetabular cup navigation as a result of a simplified palpation method of the frontal pelvic plane].

Science.gov (United States)

Richolt, J A; Rittmeister, M E

2006-01-01

Computer assisted navigation of the acetabular cup in THR requires reliable digitalisation of bony landmarks defining the frontal pelvic plane by user driven palpation. According to the system recommendations the subcutaneous fat should be held aside during epicutaneous digitalization. To improve intraoperative practicability this is often neglected in the symphysis area. In these cases the fat is just compressed and not pushed aside. In this study soft tissue thickness was assessed by ultrasound and pelvic geometry was measured in 72 patients to quantify potential misinterpretation of cup anteversion triggered by the simplified palpation. As reference we employed data of the same patients that had been acquired by recommended palpation. Anteversion misinterpretation averaged at 8.2 degrees with extremes from 2 to 24 degrees. There were no correlations between soft tissue thickness or misinterpretation and body weight, height and pelvic size. Anteversion misinterpretation was highly significant worse compared to the reference data. In 31 % of the patients the anteversion misinterpretation of a navigation system would have been wrong by over 10 degrees and in 81 % over 5 degrees . Therefore the simplified palpation should not be utilized. For epicutaneous digitalization of the bony landmarks it is mandatory to push the subcutaneous fat aside.

Combination of Nasolabial V-Y Advancement Flap and Glabellar Subcutaneous Pedicled Flap for Reconstruction of Medial Canthal Defect

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Hiromichi Matsuda

2014-02-01

Full Text Available A 77-year-old woman presented with a 1-year history of a right medial canthal tumor, which was histopathologically diagnosed as a basal cell carcinoma. After removal of the tumor with a 4-mm safety margin, the defect occupied the areas superior and inferior to the medial canthal tendon. We first reconstructed the lower part of the defect using a nasolabial V-Y advancement flap to make an elliptic defect in the upper part. We then created a glabellar subcutaneous pedicled flap to match the residual upper elliptic defect with the major axis set along a relaxed skin tension line. The pedicled glabellar flap was passed through a subcutaneous tunnel to the upper residual defect. At 6 months postoperatively, the patient showed no tumor recurrence and a good cosmetic outcome.

Comparative Analysis of Effect of Density, Insertion Angle and Reinsertion on Pull-Out Strength of Single and Two Pedicle Screw Constructs Using Synthetic Bone Model

OpenAIRE

Krishnan, Venkatesh; Varghese, Vicky; Kumar, Gurunathan Saravana

2016-01-01

Study Design Biomechanical study. Purpose To determine the effect of density, insertion angle and reinsertion on pull-out strength of pedicle screw in single and two screw-rod configurations. Overview of Literature Pedicle screw pull-out studies have involved single screw construct, whereas two screws and rod constructs are always used in spine fusions. Extrapolation of results using the single screw construct may lead to using expensive implants or increasing the fusion levels specifically i...

Current Role of Computer Navigation in Total Knee Arthroplasty.

Science.gov (United States)

Jones, Christopher W; Jerabek, Seth A

2018-01-31

Computer-assisted surgical (CAS) navigation has been developed with the aim of improving the accuracy and precision of total knee arthroplasty (TKA) component positioning and therefore overall limb alignment. The historical goal of knee arthroplasty has been to restore the mechanical alignment of the lower limb by aligning the femoral and tibial components perpendicular to the mechanical axis of the femur and tibia. Despite over 4 decades of TKA component development and nearly 2 decades of interest in CAS, the fundamental question remains; does the alignment goal and/or the method of achieving that goal affect the outcome of the TKA in terms of patient-reported outcome measures and/or overall survivorship? The quest for reliable and reproducible achievement of the intraoperative alignment goal has been the primary motivator for the introduction, development, and refinement of CAS navigation. Numerous proprietary systems now exist, and rapid technological advancements in computer processing power are stimulating further development of robotic surgical systems. Three categories of CAS can be defined: image-based large-console navigation; imageless large-console navigation, and more recently, accelerometer-based handheld navigation systems have been developed. A review of the current literature demonstrates that there are enough well-designed studies to conclude that both large-console CAS and handheld navigation systems improve the accuracy and precision of component alignment in TKA. However, missing from the evidence base, other than the subgroup analysis provided by the Australian Orthopaedic Association National Joint Replacement Registry, are any conclusive demonstrations of a clinical superiority in terms of improved patient-reported outcome measures and/or decreased cumulative revision rates in the long term. Few authors would argue that accuracy of alignment is a goal to ignore; therefore, in the absence of clinical evidence, many of the arguments against

Simulated lumbar minimally invasive surgery educational model with didactic and technical components.

Science.gov (United States)

Chitale, Rohan; Ghobrial, George M; Lobel, Darlene; Harrop, James

2013-10-01

The learning and development of technical skills are paramount for neurosurgical trainees. External influences and a need for maximizing efficiency and proficiency have encouraged advancements in simulator-based learning models. To confirm the importance of establishing an educational curriculum for teaching minimally invasive techniques of pedicle screw placement using a computer-enhanced physical model of percutaneous pedicle screw placement with simultaneous didactic and technical components. A 2-hour educational curriculum was created to educate neurosurgical residents on anatomy, pathophysiology, and technical aspects associated with image-guided pedicle screw placement. Predidactic and postdidactic practical and written scores were analyzed and compared. Scores were calculated for each participant on the basis of the optimal pedicle screw starting point and trajectory for both fluoroscopy and computed tomographic navigation. Eight trainees participated in this module. Average mean scores on the written didactic test improved from 78% to 100%. The technical component scores for fluoroscopic guidance improved from 58.8 to 52.9. Technical score for computed tomography-navigated guidance also improved from 28.3 to 26.6. Didactic and technical quantitative scores with a simulator-based educational curriculum improved objectively measured resident performance. A minimally invasive spine simulation model and curriculum may serve a valuable function in the education of neurosurgical residents and outcomes for patients.

Consumer Use of "Dr Google": A Survey on Health Information-Seeking Behaviors and Navigational Needs.

Science.gov (United States)

Lee, Kenneth; Hoti, Kreshnik; Hughes, Jeffery David; Emmerton, Lynne M

2015-12-29

The Internet provides a platform to access health information and support self-management by consumers with chronic health conditions. Despite recognized barriers to accessing Web-based health information, there is a lack of research quantitatively exploring whether consumers report difficulty finding desired health information on the Internet and whether these consumers would like assistance (ie, navigational needs). Understanding navigational needs can provide a basis for interventions guiding consumers to quality Web-based health resources. We aimed to (1) estimate the proportion of consumers with navigational needs among seekers of Web-based health information with chronic health conditions, (2) describe Web-based health information-seeking behaviors, level of patient activation, and level of eHealth literacy among consumers with navigational needs, and (3) explore variables predicting navigational needs. A questionnaire was developed based on findings from a qualitative study on Web-based health information-seeking behaviors and navigational needs. This questionnaire also incorporated the eHealth Literacy Scale (eHEALS; a measure of self-perceived eHealth literacy) and PAM-13 (a measure of patient activation). The target population was consumers of Web-based health information with chronic health conditions. We surveyed a sample of 400 Australian adults, with recruitment coordinated by Qualtrics. This sample size was required to estimate the proportion of consumers identified with navigational needs with a precision of 4.9% either side of the true population value, with 95% confidence. A subsample was invited to retake the survey after 2 weeks to assess the test-retest reliability of the eHEALS and PAM-13. Of 514 individuals who met our eligibility criteria, 400 (77.8%) completed the questionnaire and 43 participants completed the retest. Approximately half (51.3%; 95% CI 46.4-56.2) of the population was identified with navigational needs. Participants with

Study of the Navigation Method for a Snake Robot Based on the Kinematics Model with MEMS IMU

Science.gov (United States)

Dou, Lihua; Su, Zhong; Liu, Ning

2018-01-01

A snake robot is a type of highly redundant mobile robot that significantly differs from a tracked robot, wheeled robot and legged robot. To address the issue of a snake robot performing self-localization in the application environment without assistant orientation, an autonomous navigation method is proposed based on the snake robot’s motion characteristic constraints. The method realized the autonomous navigation of the snake robot with non-nodes and an external assistant using its own Micro-Electromechanical-Systems (MEMS) Inertial-Measurement-Unit (IMU). First, it studies the snake robot’s motion characteristics, builds the kinematics model, and then analyses the motion constraint characteristics and motion error propagation properties. Second, it explores the snake robot’s navigation layout, proposes a constraint criterion and the fixed relationship, and makes zero-state constraints based on the motion features and control modes of a snake robot. Finally, it realizes autonomous navigation positioning based on the Extended-Kalman-Filter (EKF) position estimation method under the constraints of its motion characteristics. With the self-developed snake robot, the test verifies the proposed method, and the position error is less than 5% of Total-Traveled-Distance (TDD). In a short-distance environment, this method is able to meet the requirements of a snake robot in order to perform autonomous navigation and positioning in traditional applications and can be extended to other familiar multi-link robots. PMID:29547515

Study of the Navigation Method for a Snake Robot Based on the Kinematics Model with MEMS IMU.

Science.gov (United States)

Zhao, Xu; Dou, Lihua; Su, Zhong; Liu, Ning

2018-03-16

A snake robot is a type of highly redundant mobile robot that significantly differs from a tracked robot, wheeled robot and legged robot. To address the issue of a snake robot performing self-localization in the application environment without assistant orientation, an autonomous navigation method is proposed based on the snake robot's motion characteristic constraints. The method realized the autonomous navigation of the snake robot with non-nodes and an external assistant using its own Micro-Electromechanical-Systems (MEMS) Inertial-Measurement-Unit (IMU). First, it studies the snake robot's motion characteristics, builds the kinematics model, and then analyses the motion constraint characteristics and motion error propagation properties. Second, it explores the snake robot's navigation layout, proposes a constraint criterion and the fixed relationship, and makes zero-state constraints based on the motion features and control modes of a snake robot. Finally, it realizes autonomous navigation positioning based on the Extended-Kalman-Filter (EKF) position estimation method under the constraints of its motion characteristics. With the self-developed snake robot, the test verifies the proposed method, and the position error is less than 5% of Total-Traveled-Distance (TDD). In a short-distance environment, this method is able to meet the requirements of a snake robot in order to perform autonomous navigation and positioning in traditional applications and can be extended to other familiar multi-link robots.

Surgical treatment of gynecomastia with severe ptosis: periareolar incision and dermal double areolar pedicle technique.

Science.gov (United States)

Cannistra, Claudio; Piedimonte, Andrea; Albonico, Fiorella

2009-11-01

Gynecomastia is a morphostructural impairment of the mammary region in men caused by parenchymal hypertrophy or a cutaneous distortion of breast skin covering or both. The clinical classification introduced by Simon et al. in 1973 ranks gynecomastia in three degrees. Each subtype can be treated with a specific technique. This article describes an alternative surgical procedure for treating gynecomastia with severe ptosis(type III and type IIIb of Simon's classification). Fifty-eight patients were treated for gynecomastia in our Plastic Surgery Unit from 1996 to 2004. The cutaneous excess of periareolar skin is evaluated by a pinching test. A circular periareolar mark is traced corresponding to the cutaneous excess that has to be removed.Initially, liposuction of adipous tissue on the periphery of the mammary region is performed through two cutaneous 3-mm incisions at the 3 o'clock and 9 o'clock positions around the areola. After this, the liposuction incisions are enlarged from 10 o'clock to 8 o'clock and from 2 o'clockto 4 o'clock to create access for the mastectomy. This dissection creates a double dermal areolar pedicle. The new areolar position is fixed with a Benelli round block suture. A resolution of the morphologic deformity without evident scars after hair growth and a correction of the breast deformity has been observed in the 6-month follow-ups conducted for all the patients. We observed that the vascular-nervous net under the areola at 12 o'clock and 6 o'clock is very important, more so than the lateral pedicle, and the conservation of a double vascular-nervous pedicle reduces significantly the risk of areolar necrosis, especially in cases of gynecomastia type III and in cases where there is a high degree of breast malformation such as the tuberous breast.

Finding Objects for Assisting Blind People

OpenAIRE

Yi, Chucai; Flores, Roberto W.; Chincha, Ricardo; Tian, YingLi

2013-01-01

Computer vision technology has been widely used for blind assistance, such as navigation and wayfinding. However, few camera-based systems are developed for helping blind or visually-impaired people to find daily necessities. In this paper, we propose a prototype system of blind-assistant object finding by camera-based network and matching-based recognition. We collect a dataset of daily necessities and apply Speeded-Up Robust Features (SURF) and Scale Invariant Feature Transform (SIFT) featu...

Theoretical Limits of Lunar Vision Aided Navigation with Inertial Navigation System

Science.gov (United States)

2015-03-26

THEORETICAL LIMITS OF LUNAR VISION AIDED NAVIGATION WITH INERTIAL NAVIGATION SYSTEM THESIS David W. Jones, Capt, USAF AFIT-ENG-MS-15-M-020 DEPARTMENT...Government and is not subject to copyright protection in the United States. AFIT-ENG-MS-15-M-020 THEORETICAL LIMITS OF LUNAR VISION AIDED NAVIGATION WITH...DISTRIBUTION UNLIMITED. AFIT-ENG-MS-15-M-020 THEORETICAL LIMITS OF LUNAR VISION AIDED NAVIGATION WITH INERTIAL NAVIGATION SYSTEM THESIS David W. Jones

An Outdoor Navigation System for Blind Pedestrians Using GPS and Tactile-Foot Feedback

Directory of Open Access Journals (Sweden)

Ramiro Velázquez

2018-04-01

Full Text Available This paper presents a novel, wearable navigation system for visually impaired and blind pedestrians that combines a global positioning system (GPS for user outdoor localization and tactile-foot stimulation for information presentation. Real-time GPS data provided by a smartphone are processed by dedicated navigation software to determine the directions to a destination. Navigational directions are then encoded as vibrations and conveyed to the user via a tactile display that inserts into the shoe. The experimental results showed that users were capable of recognizing with high accuracy the tactile feedback provided to their feet. The preliminary tests conducted in outdoor locations involved two blind users who were guided along 380–420 m predetermined pathways, while sharing the space with other pedestrians and facing typical urban obstacles. The subjects successfully reached the target destinations. The results suggest that the proposed system enhances independent, safe navigation of blind pedestrians and show the potential of tactile-foot stimulation in assistive devices.

The Use of Percutaneous Lumbar Fixation Screws for Bilateral Pedicle Fractures with an Associated Dislocation of a Lumbar Disc Prosthesis

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William D. Harrison

2013-01-01

Full Text Available Study Design. Case report. Objective. To identify a safe technique for salvage surgery following complications of total disc replacement. Summary of Background Data. Lumbar total disc replacement (TDR is considered by some as the gold standard for discogenic back pain. Revision techniques for TDR and their complications are in their infancy. This case describes a successful method of fixation for this complex presentation. Methods and Results. A 48-year-old male with lumbar degenerative disc disease and no comorbidities. Approximately two weeks postoperatively for a TDR, the patient represented with acute severe back pain and the TDR polyethylene inlay was identified as dislocated anteriorly. Subsequent revision surgery failed immediately as the polyethylene inlay redislocated intraoperatively. Further radiology identified bilateral pedicle fractures, previously unseen on the plain films. The salvage fusion of L5/S1 reutilized the anterior approach with an interbody fusion cage and bone graft. The patient was then turned intraoperatively and redraped. The percutaneous pedicle screws were used to fix L5 to the sacral body via the paracoccygeal corridor. Conclusion. The robust locking screw in the percutaneous screw allowed a complete fixation of the pedicle fractures. At 3-year followup, the patient has an excellent result and has returned to playing golf.

Image navigation as a means to expand the boundaries of fluorescence-guided surgery.

Science.gov (United States)

Brouwer, Oscar R; Buckle, Tessa; Bunschoten, Anton; Kuil, Joeri; Vahrmeijer, Alexander L; Wendler, Thomas; Valdés-Olmos, Renato A; van der Poel, Henk G; van Leeuwen, Fijs W B

2012-05-21

Hybrid tracers that are both radioactive and fluorescent help extend the use of fluorescence-guided surgery to deeper structures. Such hybrid tracers facilitate preoperative surgical planning using (3D) scintigraphic images and enable synchronous intraoperative radio- and fluorescence guidance. Nevertheless, we previously found that improved orientation during laparoscopic surgery remains desirable. Here we illustrate how intraoperative navigation based on optical tracking of a fluorescence endoscope may help further improve the accuracy of hybrid surgical guidance. After feeding SPECT/CT images with an optical fiducial as a reference target to the navigation system, optical tracking could be used to position the tip of the fluorescence endoscope relative to the preoperative 3D imaging data. This hybrid navigation approach allowed us to accurately identify marker seeds in a phantom setup. The multispectral nature of the fluorescence endoscope enabled stepwise visualization of the two clinically approved fluorescent dyes, fluorescein and indocyanine green. In addition, the approach was used to navigate toward the prostate in a patient undergoing robot-assisted prostatectomy. Navigation of the tracked fluorescence endoscope toward the target identified on SPECT/CT resulted in real-time gradual visualization of the fluorescent signal in the prostate, thus providing an intraoperative confirmation of the navigation accuracy.

Clinical effects of posterior pedicle screw fixation on spinal deformity in growing period: a report of 360 cases

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Zheng-lei WANG

2011-08-01

Full Text Available Objective To observe the effect of a new kind of pedicle screw frame system with sliding terminus and locked middle segment on spinal deformity in growing period.Methods Three hundred and sixty patients in growing period were involved in the present study,and among them 82 were suffering from congenital scoliosis,218 idiopathic scoliosis and 60 kyphosis.All the patients were treated with the pedicle screw frame system with sliding terminus and locked middle segment.The treatment effects and postoperative complications were observed,and the Cobb angle before and after the operation was compared.Results The Cobb angle of 300 scoliosis patients was corrected from 53°±3° to 8°±2°,and the Cobb angle of 60 kyphosis patients was corrected from 60°±2° to 25°±3°,and the corrective effect was satisfactory.The correction rate of patients with Cobb angle ≤50° was 80%.Two hundred and ten patients were followed-up for 1 to 6 years,and the longitudinal growth of spine was 1.5-4.0cm.No severe complication,such as screw fracture,rod fracture or nerve injury,occurred.Conclusion The pedicle screw frame system with sliding terminus had a favorable three-dimensional correction effect,and the spine growth would not be restricted,and there was no stiffness,vertebral rotation,or distortion of shaft after operation.

Virtual modeling of robot-assisted manipulations in abdominal surgery.

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Berelavichus, Stanislav V; Karmazanovsky, Grigory G; Shirokov, Vadim S; Kubyshkin, Valeriy A; Kriger, Andrey G; Kondratyev, Evgeny V; Zakharova, Olga P

2012-06-27

To determine the effectiveness of using multidetector computed tomography (MDCT) data in preoperative planning of robot-assisted surgery. Fourteen patients indicated for surgery underwent MDCT using 64 and 256-slice MDCT. Before the examination, a specially constructed navigation net was placed on the patient's anterior abdominal wall. Processing of MDCT data was performed on a Brilliance Workspace 4 (Philips). Virtual vectors that imitate robotic and assistant ports were placed on the anterior abdominal wall of the 3D model of the patient, considering the individual anatomy of the patient and the technical capabilities of robotic arms. Sites for location of the ports were directed by projection on the roentgen-positive tags of the navigation net. There were no complications observed during surgery or in the post-operative period. We were able to reduce robotic arm interference during surgery. The surgical area was optimal for robotic and assistant manipulators without any need for reinstallation of the trocars. This method allows modeling of the main steps in robot-assisted intervention, optimizing operation of the manipulator and lowering the risk of injuries to internal organs.

Autonomous vehicle navigation utilizing fuzzy controls concepts for a next generation wheelchair.

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Hansen, J D; Barrett, S F; Wright, C H G; Wilcox, M

2008-01-01

Three different positioning techniques were investigated to create an autonomous vehicle that could accurately navigate towards a goal: Global Positioning System (GPS), compass dead reckoning, and Ackerman steering. Each technique utilized a fuzzy logic controller that maneuvered a four-wheel car towards a target. The reliability and the accuracy of the navigation methods were investigated by modeling the algorithms in software and implementing them in hardware. To implement the techniques in hardware, positioning sensors were interfaced to a remote control car and a microprocessor. The microprocessor utilized the sensor measurements to orient the car with respect to the target. Next, a fuzzy logic control algorithm adjusted the front wheel steering angle to minimize the difference between the heading and bearing. After minimizing the heading error, the car maintained a straight steering angle along its path to the final destination. The results of this research can be used to develop applications that require precise navigation. The design techniques can also be implemented on alternate platforms such as a wheelchair to assist with autonomous navigation.

Experiences of cancer patients in a patient navigation program: a qualitative systematic review.

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Tan, Clarice Hwee Hoon; Wilson, Sally; McConigley, Ruth

2015-03-12

A patient navigation program is a model of care which entails trained personnel providing individualized and assistive care to adult oncology patients to help the patients overcome barriers. A further aim of the program is to achieve continuity of care as patients experience the complex healthcare system. Patient navigation is a new model of care in many institutions, and as such the experiences of patients in the patient navigation program remains inconclusive. The review seeks to understand the experiences of adult patients in patient navigation programs and how patient navigators impact the challenges patients encounter in the cancer care continuum. Participants of interest were adult cancer patients more than 18 years of age who are receiving or have received cancer care and are in a patient navigation program or had been in a hospital patient navigation program. Types of intervention(s)/phenomena of interest: The phenomenon of interest was the experiences of adult cancer patients who used patient navigation programs in hospital including how patient navigators impact on the challenges patients encounter in the cancer care continuum. Types of studies: This review considered studies that focused on qualitative data including, but not limited to, designs such as phenomenology, grounded theory, action research and exploratory studies. The review includes patient navigation programs within a hospital setting. Types of outcome: The review sought to understand the experiences of patients with cancer in patient navigation programs in the hospital. A three-step search strategy was used. An initial search to identify keywords was undertaken in PubMed and Science Direct followed by an expanded search using all identified keywords and index terms specific to each included database. The reference lists of included papers were then searched for any other relevant studies. Each paper was assessed independently by two reviewers for methodological quality using the Joanna

Collaborative Assistive Robot for Mobility Enhancement (CARMEN) The bare necessities assisted wheelchair navigation and beyond

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Urdiales, Cristina

2012-01-01

In nowadays aging society, many people require mobility assistance. Sometimes, assistive devices need a certain degree of autonomy when users' disabilities difficult manual control. However, clinicians report that excessive assistance may lead to loss of residual skills and frustration. Shared control focuses on deciding when users need help and providing it. Collaborative control aims at giving just the right amount of help in a transparent, seamless way. This book presents the collaborative control paradigm. User performance may be indicative of physical/cognitive condition, so it is used to decide how much help is needed. Besides, collaborative control integrates machine and user commands so that people contribute to self-motion at all times. Collaborative control was extensively tested for 3 years using a robotized wheelchair at a rehabilitation hospital in Rome with volunteer inpatients presenting different disabilities, ranging from mild to severe. We also present a taxonomy of common metrics for wheelc...

Introduction to the Navigation Team: Johnson Space Center EG6 Internship

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Gualdoni, Matthew

2017-01-01

The EG6 navigation team at NASA Johnson Space Center, like any team of engineers, interacts with the engineering process from beginning to end; from exploring solutions to a problem, to prototyping and studying the implementations, all the way to polishing and verifying a final flight-ready design. This summer, I was privileged enough to gain exposure to each of these processes, while also getting to truly experience working within a team of engineers. My summer can be broken up into three projects: i) Initial study and prototyping: investigating a manual navigation method that can be utilized onboard Orion in the event of catastrophic failure of navigation systems; ii) Finalizing and verifying code: altering a software routine to improve its robustness and reliability, as well as designing unit tests to verify its performance; and iii) Development of testing equipment: assisting in developing and integrating of a high-fidelity testbed to verify the performance of software and hardware.

Development of A Plant Navigation System

International Nuclear Information System (INIS)

Furuta, Tomihiko; Nakagawa, Tsuneo; Kubota, Ryuji; Ikeda, Kouji

1998-01-01

A 'Plant Navigation System (PNS)' is under development to assist nuclear power plant (NPP) operators by automatically displaying the plant situation and plant operational procedures on a CRT screen when abnormalities occur. The operation procedures given in a symptom-oriented manual are expressed in a tree - type flowchart (modified PAD). The optimum operation procedure for an NPP is selected automatically using built-in diagnostic logics based on the current status of the NPP. Concerning the plant situation, the PNS displays important information only on the current status of the NPP. A prototype PNS system is being constructed. (authors)

Acute L5 pedicle fracture and contralateral spondylolysis in a 12-year-old boy: a case report

Science.gov (United States)

Mary, Pierre; de Carvalho, Antonio; Pointe, Hubert Ducou le; Damsin, Jean-Paul; Filipe, Georges

2007-01-01

Acute unilateral L5 pedicle fracture associated with a pre-existing contralateral spondylolysis is a rare lesion. We report a case in a non-competitive 12-year-old boy. We present the clinical, radiological and specific management of this rare condition. The clinical and radiological draft of this patient was reviewed. The follow-up was 30 months after fracture healing. Some cases reported in the literature were analyzed and our clinical findings and therapeutic strategy was compared and discussed. Non-operative treatment was done including full-time bracing in a modified Boston brace incorporating one thigh for 3 months. Plain radiographs and computed tomographic (CT)-scan performed at 3 and 6 months showed progressive healing of the pedicle fracture and no modification of the contralateral isthmic spondylolytic lesion. At final follow-up, the patient was asymptomatic and resumed all his activities. In skeletally immature patients, we think that conservative treatment should be considered as a treatment option for this unusual injury. PMID:17520295

Study of the Navigation Method for a Snake Robot Based on the Kinematics Model with MEMS IMU

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Xu Zhao

2018-03-01

Full Text Available A snake robot is a type of highly redundant mobile robot that significantly differs from a tracked robot, wheeled robot and legged robot. To address the issue of a snake robot performing self-localization in the application environment without assistant orientation, an autonomous navigation method is proposed based on the snake robot’s motion characteristic constraints. The method realized the autonomous navigation of the snake robot with non-nodes and an external assistant using its own Micro-Electromechanical-Systems (MEMS Inertial-Measurement-Unit (IMU. First, it studies the snake robot’s motion characteristics, builds the kinematics model, and then analyses the motion constraint characteristics and motion error propagation properties. Second, it explores the snake robot’s navigation layout, proposes a constraint criterion and the fixed relationship, and makes zero-state constraints based on the motion features and control modes of a snake robot. Finally, it realizes autonomous navigation positioning based on the Extended-Kalman-Filter (EKF position estimation method under the constraints of its motion characteristics. With the self-developed snake robot, the test verifies the proposed method, and the position error is less than 5% of Total-Traveled-Distance (TDD. In a short-distance environment, this method is able to meet the requirements of a snake robot in order to perform autonomous navigation and positioning in traditional applications and can be extended to other familiar multi-link robots.

Pedicle distraction increases intervertebral and spinal canal area in a cadaver and bone model

OpenAIRE

Hughes Matthew; Papadakos Nikolaos; Bishop Tim; Bernard Jason

2018-01-01

Introduction: Lumbar spinal stenosis is degenerative narrowing of the spinal canal and/or intervertebral foramen causing compression of the spinal cord and nerve roots. Traditional decompression techniques can often cause significant trauma and vertebral instability. This paper evaluates a method of increasing pedicle length to decompress the spinal and intervertebral foramen, which could be done minimally invasive. Methods: Three Sawbone (Sawbones Europe, Sweden) and 1 cadaveric lumbar sp...

Fetal Intelligent Navigation Echocardiography (FINE): a novel method for rapid, simple, and automatic examination of the fetal heart.

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Yeo, Lami; Romero, Roberto

2013-09-01

To describe a novel method (Fetal Intelligent Navigation Echocardiography (FINE)) for visualization of standard fetal echocardiography views from volume datasets obtained with spatiotemporal image correlation (STIC) and application of 'intelligent navigation' technology. We developed a method to: 1) demonstrate nine cardiac diagnostic planes; and 2) spontaneously navigate the anatomy surrounding each of the nine cardiac diagnostic planes (Virtual Intelligent Sonographer Assistance (VIS-Assistance®)). The method consists of marking seven anatomical structures of the fetal heart. The following echocardiography views are then automatically generated: 1) four chamber; 2) five chamber; 3) left ventricular outflow tract; 4) short-axis view of great vessels/right ventricular outflow tract; 5) three vessels and trachea; 6) abdomen/stomach; 7) ductal arch; 8) aortic arch; and 9) superior and inferior vena cava. The FINE method was tested in a separate set of 50 STIC volumes of normal hearts (18.6-37.2 weeks of gestation), and visualization rates for fetal echocardiography views using diagnostic planes and/or VIS-Assistance® were calculated. To examine the feasibility of identifying abnormal cardiac anatomy, we tested the method in four cases with proven congenital heart defects (coarctation of aorta, tetralogy of Fallot, transposition of great vessels and pulmonary atresia with intact ventricular septum). In normal cases, the FINE method was able to generate nine fetal echocardiography views using: 1) diagnostic planes in 78-100% of cases; 2) VIS-Assistance® in 98-100% of cases; and 3) a combination of diagnostic planes and/or VIS-Assistance® in 98-100% of cases. In all four abnormal cases, the FINE method demonstrated evidence of abnormal fetal cardiac anatomy. The FINE method can be used to visualize nine standard fetal echocardiography views in normal hearts by applying 'intelligent navigation' technology to STIC volume datasets. This method can simplify

The pedicled masseter muscle transfer for smile reconstruction in facial paralysis: repositioning the origin and insertion.

Science.gov (United States)

Matic, Damir B; Yoo, John

2012-08-01

The pedicled masseter muscle transfer (PMMT) is introduced as a new reconstructive option for dynamic smile restoration in patients with facial paralysis. The masseter muscle is detached from both its origin and insertion and transferred to a new position to imitate the function of the native zygomaticus major muscle. Part one of this study consisted of cadaveric dissections of 4 heads (eight sides) in order to determine whether the masseter muscle could be (a) pedicled solely by its dominant neurovascular bundle and (b) repositioned directly over the native zygomaticus major. The second part of the study consisted of clinical assessments in three patients in order to confirm the applicability of this muscle transfer. Commissure excursion and vector of contraction following PMMT were compared to the non-paralyzed side. In all eight sides, the masseter muscles were successfully isolated on their pedicle and transposed on top of and in-line with the ipsilateral zygomaticus major. The mean length of the masseter and its angle from Frankfurt's horizontal line after transposition compared favorably to the native zygomaticus major muscle. In the clinical cases, the mean commissure movements of the paralyzed and normal sides were 7 mm and 12 mm respectively. The mean angles of commissural movement for the paralyzed and normal sides were 62° and 59° respectively. The PMMT can be used as a dynamic reconstruction for patients with permanent facial paralysis. As we gain experience with the PMMT, it may be possible to use it as a first-line option for patients not eligible for free micro-neurovascular reconstruction. Copyright © 2012 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Maneuverability Strategy for Assistive Maneuverability Strategy for Assistive Vehicles Navigating within Confined Space

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Fernando Auat Cheein

2011-08-01

Full Text Available In this work, a path planning strategy for both a car-like and a unicycle type assistive vehicles is presented. The assistive vehicles are confined to restricted environments. The path planning strategy uses the environment information to generate a kinematically plausible path to be followed by the vehicle. The environment information is provided by a SLAM (Simultaneous Localization and Mapping algorithm implemented on the vehicles. The map generated by the SLAM algorithm compensates the lack of sensor at the back of the vehicles' chassis. A Monte Carlo-based technique is used to find the optimum path given the SLAM information. A visual and user-friendly interface enhances the user-vehicle communication allowing him/her to select a desired position and orientation (pose that the vehicle should reach within the mapped environment. A trajectory controller drives the vehicle until it reaches a neighborhood of the desired pose. Several real-time experimental results within real environments are also shown herein.

Evaluation of the Effect of Fixation Angle between Polyaxial Pedicle Screw Head and Rod on the Failure of Screw-Rod Connection

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Engin Çetin

2015-01-01

Full Text Available Introduction. Polyaxial screws had been only tested according to the ASTM standards (when they were perpendicularly positioned to the rod. In this study, effects of the pedicle screws angled fixation to the rod on the mechanical properties of fixation were investigated. Materials and Method. 30 vertically fixed screws and 30 screws fixed with angle were used in the study. Screws were used in three different diameters which were 6.5 mm, 7.0 mm, and 7.5 mm, in equal numbers. Axial pull-out and flexion moment tests were performed. Test results compared with each other using appropriate statistical methods. Results. In pull-out test, vertically fixed screws, in 6.5 mm and 7.0 mm diameter, had significantly higher maximum load values than angled fixed screws with the same diameters (P<0.01. Additionally, vertically fixed screws, in all diameters, had significantly greater stiffness according to corresponding size fixed with angle (P<0.005. Conclusion. Fixing the pedicle screw to the rod with angle significantly decreased the pull-out stiffness in all diameters. Similarly, pedicle screw instrumentation fixed with angle decreased the minimum sagittal angle between the rod and the screw in all diameters for flexion moment test but the differences were not significant.

The Pedicled Buccal Fat Pad: Anatomical Study of the New Flap for Skull Base Defect Reconstruction After Endoscopic Endonasal Transpterygoid Surgery

Science.gov (United States)

Golbin, Denis A.; Lasunin, Nikolay V.; Cherekaev, Vasily A.; Polev, Georgiy A.

2016-01-01

Objectives To evaluate the efficacy and safety of using a buccal fat pad for endoscopic skull base defect reconstruction. Design Descriptive anatomical study with an illustrative case presentation. Setting Anatomical study was performed on 12 fresh human cadaver specimens with injected arteries (24 sides). Internal carotid artery was exposed in the coronal plane via the endoscopic transpterygoid approach. The pedicled buccal fat pad was used for reconstruction. Participants: 12 human cadaver head specimens; one patient operated using the proposed technique. Main outcome measures: Proximity of the buccal fat pad flap to the defect, compliance of the flap, comfort and safety of harvesting procedure, and compatibility with the Hadad–Bassagasteguy nasoseptal flap. Results: Harvesting procedure was performed using anterior transmaxillary corridor. The pedicled buccal fat pad flap can be used to pack the sphenoid sinus or cover the internal carotid artery from cavernous to upper parapharyngeal segment. Conclusion The buccal fat pad can be safely harvested through the same approach without external incisions and is compliant enough to conform to the skull base defect. The proposed pedicled flap can replace free abdominal fat in central skull base reconstruction. The volume of the buccal fat pad allows obliteration of the sphenoid sinus or upper parapharyngeal space. PMID:28180047

33 CFR 2.36 - Navigable waters of the United States, navigable waters, and territorial waters.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Navigable waters of the United States, navigable waters, and territorial waters. 2.36 Section 2.36 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY GENERAL JURISDICTION Jurisdictional Terms § 2.36 Navigable waters...

Hyperbaric oxygen therapy and surgical delay improve flap survival of reverse pedicle flaps for lower third leg and foot reconstruction

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Pradeoth Mukundan Korambayil

2015-06-01

Full Text Available Aim: The purpose of the study is to present a management protocol for various types of soft tissue defects of the distal third region of leg and foot treated with pedicle flaps, by including hyperbaric oxygen (HBO therapy in the treatment regimen with flap delay. Methods: We present a prospective study of 23 patients with various types of soft tissue defects of the foot, and lower third of leg managed in our institution from December 2012 to December 2013. All soft tissue defects were treated by a reverse pedicle flap. Twelve patients were managed with flap delay with HBO therapy and 11 patients with immediate flaps without HBO therapy. The postoperative period, hospital course, and follow-up were documented. Results: Of 12 patients with flap delay and HBO, 10 patients did not suffer any complications secondary to flap transfer. One patient had discoloration of the tip of the flap, which settled without the intervention, and 1 patient had recurrent abscess formation, which required debridement and closure. Of 11 patients with direct transfer, 6 patients presented with complications including flap congestion, partial flap loss, and tip necrosis, which required secondary intervention. Conclusion: HBO therapy is a useful adjunct in flap delay of the reverse pedicle flap for soft tissue reconstruction of the lower third of the leg and foot regions.

Access to Adequate Healthcare for Hmong Women: A Patient Navigation Program to Increase Pap Test Screening

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Moon S. Chen, Jr

2010-01-01

Full Text Available This paper describes the development and implementation of a Hmong Cervical Cancer Intervention Program utilizing a patient navigation model to raise cervical cancer awareness for Hmong women through educational workshops and to assist Hmong women in obtaining a Pap test. Out of 402 women who participated in a baseline survey, the Patient Navigation Program was able to enroll 109 participants who had not had a Pap test in the past 3 years and had never had a Pap test. Through utilization of outreach, an awareness campaign and patient navigation support, at least 38 percent of 109 participants obtained a Pap test. Overall, 21 workshops and 43 outreach activities were conducted by the Hmong Women’s Heritage Association, leading to 63 percent of those enrolled in the Patient Navigation Program who could be contacted to obtain a Pap test.

Safety and cost-effectiveness analysis of laparoscopic splenectomy by secondary pedicle division using monopolar electrocautery.

Science.gov (United States)

Zhou, Jianyin; Liu, Pingguo; Yin, Zhenyu; Zhao, Yilin; Wang, Xiaomin

2013-09-01

The expense of laparoscopic splenectomy (LS) has limited its use in developing countries, while medical costs are increasing worldwide. In this study, we performed LS by secondary pedicle division using monopolar electrocautery to achieve cost savings. Over seven years, we performed 45 consecutive LSs by secondary pedicle division using monopolar electrocautery (n=17) or ultrasonic shears (n=28) at a single center. These were reviewed to assess outcome and cost. Mean operating time was 179.7min, 7 conversions to open operation (15.6%) were necessary. There were four postoperative complications (8.9%) and no deaths. Twenty-three of 28 (82.1%) patients with idiopathic thrombocytopenic purpura developed a long-term positive response; and mean operative cost was RMB6,577 (US$1,034), which was much lower than that of Endo-GIATM in published reports. Between the monopolar electrocautery and ultrasonic shears groups, there were no significant differences in demographic characteristics or intraoperative and postoperative details, but operative cost was significantly lower in the former (RMB4,416, US$696 vs. RMB7,889, US$1,243; pelectrocautery is safe, efficacious and economical.

Portable Wireless Device Threat Assessment for Aircraft Navigation Radios

Science.gov (United States)

Nguyen, Truong X.; Koppen, Sandra V.; Ely, Jay J.; Williams, Reuben A.; Smith, Laura J.; Salud, Maria Theresa P.

2004-01-01

This paper addresses the concern for Wireless Local Area Network devices and two-way radios to cause electromagnetic interference to aircraft navigation radio systems. Spurious radiated emissions from various IEEE 802.11a, 802.11b, and Bluetooth devices are characterized using reverberation chambers. The results are compared with baseline emissions from standard laptop computer and personal digital assistants (PDAs) that are currently allowed for use on aircraft. The results indicate that the WLAN devices tested are not more of a threat to aircraft navigation radios than standard laptop computers and PDAs in most aircraft bands. In addition, spurious radiated emission data from seven pairs of two-way radios are provided. These two-way radios emit at much higher levels in the bands considered. A description of the measurement process, device modes of operation and the measurement results are reported.

Design and Implementation of Kana-Input Navigation System for Kids based on the Cyber Assistant

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Hiroshi Matsuda

2004-02-01

Full Text Available In Japan, it has increased the opportunity for young children to experience the personal computer in elementary schools. However, in order to use computer, many domestic barriers have confronted young children (Kids because they cannot read difficult Kanji characters and had not learnt Roman alphabet yet. As a result, they cannot input text strings by JIS Kana keyboard. In this research, we developed Kana-Input NaVigation System for kids (KINVS based on the Cyber Assistant System (CAS. CAS is a Human-Style Software Robot based on the 3D-CG real-time animation and voice synthesis technology. KINVS enables to input Hiragana/Katakana characters by mouse operation only (without keyboard operation and CAS supports them by using speaking, facial expression, body action and sound effects. KINVS displays the 3D-Stage like a classroom. In this room, Blackboard, Interactive parts to input Kana-characters, and CAS are placed. As some results of preliminary experiments, it is definitely unfit for Kids to double-click objects quickly or to move the Scrollbar by mouse dragging. So, mouse input method of KINVS are designed to use only single click and wheeler rotation. To input characters, Kids clicks or rotates the Interactive Parts. KINVS reports all information by voice speaking and Kana subtitles instead of Kanji text. Furthermore, to verify the functional feature of KINVS, we measured how long Kids had taken to input long text by using KINVS.

Cervical pedicle screw fixation at C6 and C7 A cadaveric study

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Ye Li

2015-01-01

Conclusion: The intersection of the horizontal line through the midpoint of the transverse process root and vertical line through the intersection of the posterolateral and posterior planes of the isthmus can be used as an entry point for C6 and C7 pedicle screw fixation. The screws should be inserted at 60 or 90° with the posterolateral isthmus in the horizontal plane and at 75° with the posterior isthmus in the sagittal plane. The LSC should not exceed 30 mm.

Metal Artifacts Reduction of Pedicle Screws on Spine Computed Tomography Images Using Variable Thresholding Technique

International Nuclear Information System (INIS)

Kaewlek, T.; Koolpiruck, D.; Thongvigitmanee, S.; Mongkolsuk, M.; Chiewvit, P.; Thammakittiphan, S.

2012-01-01

Metal artifacts are one of significant problems in computed tomography (CT). The streak lines and air gaps arise from metal implants of orthopedic patients, such as prosthesis, dental bucket, and pedicle screws that cause incorrect diagnosis and local treatment planning. A common technique to suppressed artifacts is by adjusting windows, but those artifacts still remain on the images. To improve the detail of spine CT images, the variable thresholding technique is proposed in this paper. Three medical cases of spine CT images categorized by the severity of artifacts (screws head, one full screw, and two full screws) were investigated. Metal regions were segmented by k-mean clustering, then transformed into a sinogram domain. The metal sinogram was identified by the variable thresholding method, and then replaced the new estimated values by linear interpolation. The modified sinogram was reconstructed by the filtered back- projection algorithm, and added the metal region back to the modified reconstructed image in order to reproduce the final image. The image quality of the proposed technique, the automatic thresholding (Kalender) technique, and window adjustment technique was compared in term of noise and signal to noise ratio (SNR). The propose method can reduce metal artifacts between pedicle screws. After processing by our proposed technique, noise in the modified images is reduced (screws head 121.15 to73.83, one full screw 160.88 to 94.04, and two full screws 199.73 to 110.05 from the initial image) and SNR is increased (screws head 0.87 to 1.88, one full screw 1.54 to 2.82, and two full screws 0.32 to 0.41 from the initial image). The variable thresholding technique can identify the suitable boundary for restoring the missing data. The efficiency of the metal artifacts reduction is indicated on the case of partial and full pedicle screws. Our technique can improve the detail of spine CT images better than automatic thresholding (Kalender) technique, and

Navigation-assisted trans-inferotemporal cortex selective amygdalohippocampectomy for mesial temporal lobe epilepsy; preserving the temporal stem.

Science.gov (United States)

Kishima, Haruhiko; Kato, Amami; Oshino, Satoru; Tani, Naoki; Maruo, Tomoyuki; Khoo, Hui Ming; Yanagisawa, Takufumi; Edakawa, Kotaro; Kobayashi, Maki; Tanaka, Masataka; Hosomi, Koichi; Hirata, Masayuki; Yoshimine, Toshiki

2017-03-01

Selective amygdalohippocampectomy (SAH) can be used to obtain satisfactory seizure control in patients with mesial temporal lobe epilepsy (MTLE). Several SAH procedures have been reported to achieve satisfactory outcomes for seizure control, but none yield fully satisfactory outcomes for memory function. We hypothesized that preserving the temporal stem might play an important role. To preserve the temporal stem, we developed a minimally invasive surgical procedure, 'neuronavigation-assisted trans-inferotemporal cortex SAH' (TITC-SAH). TITC-SAH was performed in 23 patients with MTLE (MTLE on the language-non-dominant hemisphere, n = 11). The inferior horn of the lateral ventricle was approached via the inferior or middle temporal gyrus along the inferior temporal sulcus under neuronavigation guidance. The hippocampus was dissected in a subpial manner and resected en bloc together with the parahippocampal gyrus. Seizure control at one year and memory function at 6 months postoperatively were evaluated. One year after TITC-SAH, 20 of the 23 patients were seizure-free (ILAE class 1), 2 were class 2, and 1 was class 3. Verbal memory improved significantly in 13 patients with a diagnosis of hippocampal sclerosis, for whom WMS-R scores were available both pre- and post-operatively. Improvements were seen regardless of whether the SAH was on the language-dominant or non-dominant hemisphere. No major complication was observed. Navigation-assisted TITC-SAH performed for MTLE offers a simple, minimally invasive procedure that appears to yield excellent outcomes in terms of seizure control and preservation of memory function, because this procedure does not damage the temporal stem. TITC-SAH should be one of the feasible surgical procedures for MTLE. SAH: Amygdalohippocampectomy; MTLE: Mesial temporal lobe epilepsy (MTLE); TITC-SAH: Ttrans-inferotemporal cortex SAH; ILAE: International League Against Epilepsy (ILAE); MRI: Magnetic resonance imaging; EEG

77 FR 42637 - Navigation and Navigable Waters; Technical, Organizational, and Conforming Amendments; Corrections

Science.gov (United States)

2012-07-20

... DEPARTMENT OF HOMELAND SECURITY Coast Guard 33 CFR Parts 84 and 115 [Docket No. USCG-2012-0306] RIN 1625-AB86 Navigation and Navigable Waters; Technical, Organizational, and Conforming Amendments...), the Coast Guard published a final rule entitled ``Navigation and Navigable Waters; Technical...

TARDIS: An Automation Framework for JPL Mission Design and Navigation

Science.gov (United States)

Roundhill, Ian M.; Kelly, Richard M.

2014-01-01

Mission Design and Navigation at the Jet Propulsion Laboratory has implemented an automation framework tool to assist in orbit determination and maneuver design analysis. This paper describes the lessons learned from previous automation tools and how they have been implemented in this tool. In addition this tool has revealed challenges in software implementation, testing, and user education. This paper describes some of these challenges and invites others to share their experiences.

Navigating emotions and relationship dynamics: family life review as a clinical tool for older adults during a relocation transition into an assisted living facility.

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O'Hora, Kendra A; Roberto, Karen A

2018-01-16

Relocation for the purpose of receiving care may be one of the more challenging transitions for older adults. The purpose of this study was to facilitate a family life review (FLR) session aimed at enhancing family relationships and assisting older adults in coping with the challenges associated with a relocation. Fourteen dyads comprised of older adults who relocated to an assisted living facility (ALF) and a chosen family member or friend participated in a FLR session and semi-structured follow up interview. Data were analyzed using the constant comparative method and triangulated with descriptive statistics. Emergent themes suggested participating in FLR influenced families by raising emotions, systemically thinking, and navigating the relocation. FLR facilitated positive connections, enhanced existing relationships, and promoted self-acceptance. Families indicated mutual storytelling was enjoyable and reminded them of the urgency to share their story. FLR allowed dyads to reflect and thus prompted a renewed perspective on some of the more challenging components of the relocation transition. Study findings provide insight into how families organize individual and interpersonal narratives and use these narratives during transitional times. FLR can aid families in making a smoother and fulfilling move to an ALF and other late life transitions.

A Universal Pedicle Screw and V-Rod System for Lumbar Isthmic Spondylolysis: A Retrospective Analysis of 21 Cases

Science.gov (United States)

Chen, Xiong-sheng; Zhou, Sheng-yuan; Jia, Lian-shun; Gu, Xiao-min; Fang, Lei; Zhu, Wei

2013-01-01

Objective To investigate the surgical outcome of a universal pedicle screw-V rod system and isthmic bone grafting for isthmic spondylolysis. Methods Twenty-four patients with isthmic spondylolysis at L5 and grade 0–I spondylolisthesis (Meyerding classification) received isthmic bone graft and stabilization using the universal pedicle screw-V rod system. Back pain was evaluated using the visual analog scale (VAS) and time to bone healing, improvement in spondylolisthesis and intervertebral space height at L5/S1 and L4/L5 were assessed. Results Twenty-one patients were followed up for 24 months and included in the analysis. Back pain was markedly improved at 3 months postoperatively with a statistical difference in VAS scores compared with preoperative VAS scores (Pspondylolysis and reduces back pain, prevents anterior displacement of the diseased segment and maintains intervertebral space height, thus offering a promising alternative to current approaches for isthmic spondylolysis. PMID:23691090

[Effect evaluation of over 5 year follow up of unilateral pedicle screw fixation with transforaminal lumbar interbody fusion for lumbar degenerative diseases].

Science.gov (United States)

Wang, Chong; Ying, Jin-He; Xie, Pan-Pan; Wu, Xiao-Guang

2016-07-25

To evaluate the clinical effects of over 5 year follow up of unilateral pedicle screw fixation with transforaminal lumbar interbody fusion(TLIF) in treating lumbar degenerative diseases. The clinical data of 24 patients with lumbar degenerative disease underwent unilateral pedicle screw fixation with transforaminal lumbar interbody fusion from March 2007 to October 2009, were retrospectively analyzed. There were 13 males and 11 females, aged from 34 to 68 years old with an average of 52 years. Postoperative pain and functional results were analyzed by the visual analogue scale(VAS) and Oswestry Disability Index(ODI). Radiological examination was obtained for each patient to assess the height of intervertebral space, postoperative intervertebral fusion conditions and general complications. All patients were followed up from 5 to 8 years with an average of 6.7 years. VAS scores of low back pain and leg pain decreased from preoperative 7.82±0.71, 8.42±1.24 to postoperative 1.87±0.81, 2.23±1.62, respectively( P degenerative diseases according to over 5 year follow up, however, its indications should be well considered. But the problems such as intervertebral space height of operated side loss and adjacent segment degeneration after unilateral pedicle screw fixation need further clinical study.

Radar and electronic navigation

CERN Document Server

Sonnenberg, G J

2013-01-01

Radar and Electronic Navigation, Sixth Edition discusses radar in marine navigation, underwater navigational aids, direction finding, the Decca navigator system, and the Omega system. The book also describes the Loran system for position fixing, the navy navigation satellite system, and the global positioning system (GPS). It reviews the principles, operation, presentations, specifications, and uses of radar. It also describes GPS, a real time position-fixing system in three dimensions (longitude, latitude, altitude), plus velocity information with Universal Time Coordinated (UTC). It is accur

Improved accuracy of component alignment with the implementation of image-free navigation in total knee arthroplasty.

Science.gov (United States)

Rosenberger, Ralf E; Hoser, Christian; Quirbach, Sebastian; Attal, Rene; Hennerbichler, Alfred; Fink, Christian

2008-03-01

Accuracy of implant positioning and reconstruction of the mechanical leg axis are major requirements for achieving good long-term results in total knee arthroplasty (TKA). The purpose of the present study was to determine whether image-free computer navigation technology has the potential to improve the accuracy of component alignment in TKA cohorts of experienced surgeons immediately and constantly. One hundred patients with primary arthritis of the knee underwent the unilateral total knee arthroplasty. The cohort of 50 TKAs implanted with conventional instrumentation was directly followed by the cohort of the very first 50 computer-assisted TKAs. All surgeries were performed by two senior surgeons. All patients received the Zimmer NexGen total knee prosthesis (Zimmer Inc., Warsaw, IN, USA). There was no variability regarding surgeons or surgical technique, except for the use of the navigation system (StealthStation) Treon plus Medtronic Inc., Minnesota, MI, USA). Accuracy of implant positioning was measured on postoperative long-leg standing radiographs and standard lateral X-rays with regard to the valgus angle and the coronal and sagittal component angles. In addition, preoperative deformities of the mechanical leg axis, tourniquet time, age, and gender were correlated. Statistical analyses were performed using the SPSS 15.0 (SPSS Inc., Chicago, IL, USA) software package. Independent t-tests were used, with significance set at P alignment between the two cohorts. To compute the rate of optimally implanted prostheses between the two groups we used the chi(2) test. The average postoperative radiological frontal mechanical alignment was 1.88 degrees of varus (range 6.1 degrees of valgus-10.1 degrees of varus; SD 3.68 degrees ) in the conventional cohort and 0.28 degrees of varus (range 3.7 degrees -6.0 degrees of varus; SD 1.97 degrees ) in the navigated cohort. Including all criteria for optimal implant alignment, 16 cases (32%) in the conventional cohort and 31

Versatility of Pedicled Tensor Fascia Lata Flap: A Useful and Reliable Technique for Reconstruction of Different Anatomical Districts

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Md. Sohaib Akhtar

2014-01-01

Full Text Available Aims and Objectives. The aim of this study was to evaluate the versatility of pedicled tensor fascia lata flap for reconstruction of various anatomical regions. Materials and Methods. In this retrospective study a total of 34 patients with defects over various anatomical regions were included. The defects were located over the trochanter (n=12, groin (n=8, perineum (n=6, lower anterior abdomen (n=6, gluteal region (n=1, and ischial region (n=1. The etiology of defects included trauma (n=12, infection (n=8, pressure sores (n=8, and malignancy (n=6. Reconstruction was performed using pedicled tensor fascia lata flaps. Patients were evaluated in terms of viability of the flap and donor site morbidity. The technical details of the operative procedure have also been outlined. Results. All the flaps survived well except 5 patients in which minor complications were noted and 1 who experienced complete flap loss. Of those with minor complications, 1 patient developed distal marginal necrosis and 1 developed infection which subsided within three days by dressings and antibiotics and in 2 patients partial loss of the skin graft occurred at the donor site out of which 1 required regrafting and another one healed completely with dressing and antibiotics. All the patients were followed up for an average period of 6 months, ranging from 1 to 12 months. Donor site morbidity was minimal. Conclusion. It was concluded that the pedicled tensor fascia lata flap is a versatile, reliable, easy, and less time consuming procedure for the coverage of defects around trochanter, groin, lower anterior abdomen, perineum, and ischial region.

Finding Objects for Assisting Blind People.

Science.gov (United States)

Yi, Chucai; Flores, Roberto W; Chincha, Ricardo; Tian, Yingli

2013-07-01

Computer vision technology has been widely used for blind assistance, such as navigation and wayfinding. However, few camera-based systems are developed for helping blind or visually-impaired people to find daily necessities. In this paper, we propose a prototype system of blind-assistant object finding by camera-based network and matching-based recognition. We collect a dataset of daily necessities and apply Speeded-Up Robust Features (SURF) and Scale Invariant Feature Transform (SIFT) feature descriptors to perform object recognition. Experimental results demonstrate the effectiveness of our prototype system.

Feasibility study of patient-specific surgical templates for the fixation of pedicle screws.

Science.gov (United States)

Salako, F; Aubin, C-E; Fortin, C; Labelle, H

2002-01-01

Surgery for scoliosis, as well as other posterior spinal surgeries, frequently uses pedicle screws to fix an instrumentation on the spine. Misplacement of a screw can lead to intra- and post-operative complications. The objective of this study is to design patient-specific surgical templates to guide the drilling operation. From the CT-scan of a vertebra, the optimal drilling direction and limit angles are computed from an inverse projection of the pedicle limits. The first template design uses a surface-to-surface registration method and was constructed in a CAD system by subtracting the vertebra from a rectangular prism and a cylinder with the optimal orientation. This template and the vertebra were built using rapid prototyping. The second design uses a point-to-surface registration method and has 6 adjustable screws to adjust the orientation and length of the drilling support device. A mechanism was designed to hold it in place on the spinal process. A virtual prototype was build with CATIA software. During the operation, the surgeon places either template on patient's vertebra until a perfect match is obtained before drilling. The second design seems better than the first one because it can be reused on different vertebra and is less sensible to registration errors. The next step is to build the second design and make experimental and simulations tests to evaluate the benefits of this template during a scoliosis operation.

Maneuverability Strategy for Assistive Vehicles Navigating within Confined Spaces

Directory of Open Access Journals (Sweden)

Fernando Auat Cheein

2011-08-01

Full Text Available In this work, a path planning strategy for both a car-like and a unicycle type assistive vehicles is presented. The assistive vehicles are confined to restricted environments. The path planning strategy uses the environment information to generate a kinematically plausible path to be followed by the vehicle. The environment information is provided by a SLAM (Simultaneous Localization and Mapping algorithm implemented on the vehicles. The map generated by the SLAM algorithm compensates the lack of sensor at the back of the vehicles' chassis. A Monte Carlo-based technique is used to find the optimum path given the SLAM information. A visual and user-friendly interface enhances the user-vehicle communication allowing him/her to select a desired position and orientation (pose that the vehicle should reach within the mapped environment. A trajectory controller drives the vehicle until it reaches a neighborhood of the desired pose. Several real-time experimental results within real environments are also shown herein.

33 CFR 66.05-100 - Designation of navigable waters as State waters for private aids to navigation.

Science.gov (United States)

2010-07-01

... as State waters for private aids to navigation. 66.05-100 Section 66.05-100 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION PRIVATE AIDS TO NAVIGATION State Aids to Navigation § 66.05-100 Designation of navigable waters as State waters for private aids to...

Laparoscopic assistance by operating room nurses: Results of a virtual-reality study.

Science.gov (United States)

Paschold, M; Huber, T; Maedge, S; Zeissig, S R; Lang, H; Kneist, W

2017-04-01

Laparoscopic assistance is often entrusted to a less experienced resident, medical student, or operating room nurse. Data regarding laparoscopic training for operating room nurses are not available. The aim of the study was to analyse the initial performance level and learning curves of operating room nurses in basic laparoscopic surgery compared with medical students and surgical residents to determine their ability to assist with this type of procedure. The study was designed to compare the initial virtual reality performance level and learning curves of user groups to analyse competence in laparoscopic assistance. The study subjects were operating room nurses, medical students, and first year residents. Participants performed three validated tasks (camera navigation, peg transfer, fine dissection) on a virtual reality laparoscopic simulator three times in 3 consecutive days. Laparoscopic experts were enrolled as a control group. Participants filled out questionnaires before and after the course. Nurses and students were comparable in their initial performance (p>0.05). Residents performed better in camera navigation than students and nurses and reached the expert level for this task. Residents, students, and nurses had comparable bimanual skills throughout the study; while, experts performed significantly better in bimanual manoeuvres at all times (p<0.05). The included user groups had comparable skills for bimanual tasks. Residents with limited experience reached the expert level in camera navigation. With training, nurses, students, and first year residents are equally capable of assisting in basic laparoscopic procedures. Copyright © 2017 Elsevier Ltd. All rights reserved.

Vision/INS Integrated Navigation System for Poor Vision Navigation Environments

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Youngsun Kim

2016-10-01

Full Text Available In order to improve the performance of an inertial navigation system, many aiding sensors can be used. Among these aiding sensors, a vision sensor is of particular note due to its benefits in terms of weight, cost, and power consumption. This paper proposes an inertial and vision integrated navigation method for poor vision navigation environments. The proposed method uses focal plane measurements of landmarks in order to provide position, velocity and attitude outputs even when the number of landmarks on the focal plane is not enough for navigation. In order to verify the proposed method, computer simulations and van tests are carried out. The results show that the proposed method gives accurate and reliable position, velocity and attitude outputs when the number of landmarks is insufficient.

A multicenter prospective cohort study on camera navigation training for key user groups in minimally invasive surgery

NARCIS (Netherlands)

Graafland, Maurits; Bok, Kiki; Schreuder, Henk W. R.; Schijven, Marlies P.

2014-01-01

Untrained laparoscopic camera assistants in minimally invasive surgery (MIS) may cause suboptimal view of the operating field, thereby increasing risk for errors. Camera navigation is often performed by the least experienced member of the operating team, such as inexperienced surgical residents,

Drenaje suplementario del sistema venoso superficial en colgajos pediculados Supplementary drainage of superficial venous system in pedicled flaps

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A. Fernández García

2012-06-01

Full Text Available Los colgajos pediculados pueden sufrir edema y congestión debido a que su drenaje a trevés del sistema venoso superfical es imposible y el flujo hacia el sistema profundo a nivel del pedículo es precario. Esta situación suele evolucionar hacia la necrosis parcial o la pérdida total del colgajo en pocas horas. La apertura del sistema venoso superficial permite el drenaje adecuado de los tejidos transferidos y evita estas complicaciones. Este artículo analiza el papel de las anastomosis microquirúrgicas en el sistema venoso superficial de los colgajos pediculados. Esta técnica permite comunicar el sistema venoso superfical de los tejidos transferidos con el sistema venoso superficial del territorio que rodea al defecto. Presentamos los resultados obtenidos con esta técnica en colgajos de perforante en hélice, colgajos miocutáneos, colgajos neurocutáneos y colgajos fasciograsos volteados.The pedicled flaps can suffer edema and congestion due to the impossibility of drainage toward the superficial venous system and the precarious flow via the deep system at the level of the pedicle. The evolution of this situation is usually partial necrosis or total loss of the flap in a few hours. The opening of the venous superficial system achieves an appropriate drainage of the transfered tissues and avoids these complications. In this article we analyze the role of the microsurgical anastomosis at the level of the superficial venous system of pedicled flaps. This technique allows to communicate the superficial venous system of the transfered tissues with the superficial venous system of the territory around the defect. We report the results with this method in propeller perforator flaps, miocutaneous flaps, neurocutaneous flaps and adipofascial turn over flaps.

A universal pedicle screw and V-rod system for lumbar isthmic spondylolysis: a retrospective analysis of 21 cases.

Directory of Open Access Journals (Sweden)

Xiong-sheng Chen

Full Text Available To investigate the surgical outcome of a universal pedicle screw-V rod system and isthmic bone grafting for isthmic spondylolysis.Twenty-four patients with isthmic spondylolysis at L5 and grade 0-I spondylolisthesis (Meyerding classification received isthmic bone graft and stabilization using the universal pedicle screw-V rod system. Back pain was evaluated using the visual analog scale (VAS and time to bone healing, improvement in spondylolisthesis and intervertebral space height at L5/S1 and L4/L5 were assessed.Twenty-one patients were followed up for 24 months and included in the analysis. Back pain was markedly improved at 3 months postoperatively with a statistical difference in VAS scores compared with preoperative VAS scores (P<0.001. The VAS scores were 0 to 3 at 6 months postoperatively in all patients and no back pain was reported in all patients except 2 patients who complained of back pain after prolonged sitting. X-ray examination showed a bone graft healing time of 3 to 12 months. Grade I spondylolisthesis improved to grade 0 in 4 patients and no noticeable change was observed in the remaining 17 cases. The intervertebral space height at L5/S1 was statistically increased (P<0.05 while no statistically significant change was seen at L4/L5. There was no statistically significant difference in the ROM of the intervertebral disks of L5/S1 and L4/5 before and after surgery.The universal pedicle screw-V rod system and isthmic bone grafting directly repairs isthmic spondylolysis and reduces back pain, prevents anterior displacement of the diseased segment and maintains intervertebral space height, thus offering a promising alternative to current approaches for isthmic spondylolysis.

One stage reconstruction of the floor of the mouth with a subcutaneous pedicled nasolabial flap

International Nuclear Information System (INIS)

El-Marakby, H.H.; Fouad, F.A.; Ali, H.H.

2012-01-01

Background: Nasolabial flaps have been recognised as versatile flaps for a variety of defects in the face, nose, lip and the oral cavity. Random pattern inferiorly based nasolabial flaps (NLF) have been utilised for covering small defects on the anterior floor of the mouth, but usually require a second stage procedure to divide the flap base. A subcutaneous pedicled inferiorly based nasolabial flap can provide a one stage repair of moderate sized defects of the floor of the mouth after de epithelialisation of the base of the flap. Aim: To evaluate the feasibility of a single stage reconstruction of intermediate sized defects in the oral cavity with an inferiorly based pedicled NLF. The study includes the indications of use of the flap, flap design, technique, and the complications rate. The incidence of secondary procedures and the final functional and the aesthetic results will also be evaluated. Materials and methods: A group of 20 patients presented with (T1-2) squamous cell carcinoma of the oral cavity have been treated at the Department of Surgery, National Cancer Institute, Cairo; in the period between January 2008 and September 2010. The pathology was confirmed with an incision biopsy and all metastatic work were carried out confirming that all patients were free from distant metastasis at presentation. Preoperative assessment also included assessment of the stage of the disease, the flap design and patient fitness for general anaesthesia. All patients underwent surgical excision combined with reconstruction of the defect with a subcutaneous inferiorly based pedicled NLF. The proximal part of the flap was routinely de epithelialised before it has been tunnelled through the cheek so a one stage procedure could only be required. Results: The mean age of the patients was 62.3±6 years, range (52-69 years). All patients were diagnosed with squamous cell carcinoma. The anterior floor of the mouth constituted 40% of the defects, the lateral floor of the mouth 20

Comparison of revision strategies for failed C2-posterior cervical pedicle screws: a biomechanical study.

Science.gov (United States)

Mayer, Michael; Zenner, Juliane; Bogner, Robert; Hitzl, Wolfgang; Figl, Markus; von Keudell, Arvind; Stephan, Daniel; Penzkofer, Rainer; Augat, Peter; Korn, Gundobert; Resch, Herbert; Koller, Heiko

2013-01-01

With increasing usage within challenging biomechanical constructs, failures of C2 posterior cervical pedicle screws (C2-pCPSs) will occur. The purpose of the study was therefore to investigate the biomechanical characteristics of two revision techniques after the failure of C2-pCPSs. Twelve human C2 vertebrae were tested in vitro in a biomechanical study to compare two strategies for revision screws after failure of C2-pCPSs. C2 pedicles were instrumented using unicortical 3.5-mm CPS bilaterally (Synapse/Synthes, Switzerland). Insertion accuracy was verified by fluoroscopy. C2 vertebrae were potted and fixed in an electromechanical testing machine with the screw axis coaxial to the pullout direction. Pullout testing was conducted with load and displacement data taken continuously. The peak load to failure was measured in newtons (N) and is reported as the pullout resistance (POR). After pullout, two revision strategies were tested in each vertebra. In Group-1, revision was performed with 4.0-mm C2-pCPSs. In Group-2, revision was performed with C2-pedicle bone-plastic combined with the use of a 4-mm C2-pCPSs. For the statistical analysis, the POR between screws was compared using absolute values (N) and the POR of the revision techniques normalized to that of the primary procedures (%). The POR of primary 3.5-mm CPSs was 1,140.5 ± 539.6 N for Group-1 and 1,007.7 ± 362.5 N for Group-2; the difference was not significant. In the revision setting, the POR in Group-1 was 705.8 ± 449.1 N, representing a reduction of 38.1 ± 32.9 % compared with that of primary screw fixation. For Group-2, the POR was 875.3 ± 367.9 N, representing a reduction of 13.1 ± 23.4 %. A statistical analysis showed a significantly higher POR for Group-2 compared with Group-1 (p = 0.02). Although the statistics showed a significantly reduced POR for both revision strategies compared with primary fixation (p plastic, the POR can be significantly increased compared with the use of only an

[Anatomical study and clinical application of a leg flap pedicle-included with cutaneous nerve and its concomitant vessels].

Science.gov (United States)

Liu, B; Hao, X; Goan, M

2000-05-01

To investigate the blood supply patterns and the clinical liability of a leg flap pedicle-included with cutaneous nerve and its concomitant vessels. Fresh cadaver legs with thirty-two in infants and two in adults were anatomically examined after the intravenous injection of the red Chlorinated Poly Vingl Choride (CPVC). Five patients with the soft tissue defects were selected for the treatment with the flap pedicle-included with the cutaneous nerve and its concomitant vessels. Four main cutaneous nerves were found in the leg after they perforated the deep fascia out. They were companioned with their concomitant vessels with different blood-supply pateeerns, which the upper part of the leg was in an axial pattern and the lower part was in a "chain-type anastomosing" pattern. Following the above-mentioned findings, five cases were successfully treated with this led flap. The leg flap should be designed along the cutaneous nerve and its concomitant vessels. When the flap is applied in the area of blood supply with "chain-type anastomosing" pattern, the deep fascia should also be included in the flap.

IMPROVING CAR NAVIGATION WITH A VISION-BASED SYSTEM

Directory of Open Access Journals (Sweden)

H. Kim

2015-08-01

Full Text Available The real-time acquisition of the accurate positions is very important for the proper operations of driver assistance systems or autonomous vehicles. Since the current systems mostly depend on a GPS and map-matching technique, they show poor and unreliable performance in blockage and weak areas of GPS signals. In this study, we propose a vision oriented car navigation method based on sensor fusion with a GPS and in-vehicle sensors. We employed a single photo resection process to derive the position and attitude of the camera and thus those of the car. This image georeferencing results are combined with other sensory data under the sensor fusion framework for more accurate estimation of the positions using an extended Kalman filter. The proposed system estimated the positions with an accuracy of 15 m although GPS signals are not available at all during the entire test drive of 15 minutes. The proposed vision based system can be effectively utilized for the low-cost but high-accurate and reliable navigation systems required for intelligent or autonomous vehicles.

Improving Car Navigation with a Vision-Based System

Science.gov (United States)

Kim, H.; Choi, K.; Lee, I.

2015-08-01

The real-time acquisition of the accurate positions is very important for the proper operations of driver assistance systems or autonomous vehicles. Since the current systems mostly depend on a GPS and map-matching technique, they show poor and unreliable performance in blockage and weak areas of GPS signals. In this study, we propose a vision oriented car navigation method based on sensor fusion with a GPS and in-vehicle sensors. We employed a single photo resection process to derive the position and attitude of the camera and thus those of the car. This image georeferencing results are combined with other sensory data under the sensor fusion framework for more accurate estimation of the positions using an extended Kalman filter. The proposed system estimated the positions with an accuracy of 15 m although GPS signals are not available at all during the entire test drive of 15 minutes. The proposed vision based system can be effectively utilized for the low-cost but high-accurate and reliable navigation systems required for intelligent or autonomous vehicles.

Asymmetry of the Vertebral Body and Pedicles in the True Transverse Plane in Adolescent Idiopathic Scoliosis : A CT-Based Study

NARCIS (Netherlands)

Brink, Rob C.; Schlösser, Tom P C; Colo, Dino; Vincken, Koen L.; van Stralen, Marijn; Hui, Steve C N; Chu, Winnie C W; Cheng, Jack C Y; Castelein, RM

2017-01-01

Study Design Cross-sectional. Objectives To quantify the asymmetry of the vertebral bodies and pedicles in the true transverse plane in adolescent idiopathic scoliosis (AIS) and to compare this with normal anatomy. Summary of background data There is an ongoing debate about the existence and

Clinical Application of Different Surgical Navigation Systems in Complex Craniomaxillofacial Surgery: The Use of Multisurface 3-Dimensional Images and a 2-Plane Reference System.

Science.gov (United States)

Liu, Tom J; Ko, An-Ta; Tang, Yueh-Bih; Lai, Hong-Shiee; Chien, Hsiung-Fei; Hsieh, Thomas Mon-Hsian

2016-04-01

Intraoperative navigation is a tool that provides surgeons with real-time guidance based on patients' preoperative imaging studies. The application of intraoperative navigation to neurosurgery and otolaryngology has been well documented; however, only isolated reports have analyzed its potential in the field of craniomaxillofacial surgery. From November 2010 to July 2014, 15 patients were operated on for complex craniomaxillofacial surgery with assistance by 3 different navigation systems, which used either infrared or electromagnetic technologies. We imported fine-cut (0.625-mm) computed tomographic scan images of the patients to the navigation systems whose software processed them into multisurface 3-dimentional models used as guiding material for the surgical navigation. We also developed a simple "2-plane reference system" to ensure that the final results were symmetric to the normal half of the face. Appearance outcome was evaluated by questionnaire. Of these 15 cases, 3 cases were performed with infrared-based navigation, and the remaining 12 cases were accomplished by electromagnetic technology. Most of these cases resulted in satisfactory outcomes after tumor resection, posttraumatic reconstruction, and postablative reconstruction. Navigation systems offer highly valuable intraoperative assistance in complex craniomaxillofacial surgery. Not only can these systems pinpoint deep-seated lesions as neurosurgeons or otolaryngologists do, but they can also use a simple 2-plane reference system for accurate bone alignment. Moreover, advancements in multisurface 3-D models provide us more reliable intuitive image guidance. The application of electromagnetic technology, with its smaller reference obviation of the line-of-sight problem, makes the manipulation of craniomaxillofacial surgery more comfortable.

Surgical outcome of posterior decompression, posterolateral fusion and stabilization by pedicle screw and rod in thoracolumbar tuberculosis

Directory of Open Access Journals (Sweden)

Md. Anowarul Islam

2017-05-01

Full Text Available Spinal tuberculosis causes severe complications like neurological and spinal deformity which may lead to respiratory distress, costo-pelvic impingement, paraplegia and consequent reduction in the quality and longevity of life. The aim of the present treatment is to avoid the consequence of neural complications and gain near-normal spine. Mechanical factor causes pathological fracture or dislocation of an affected vertebral body. Surgical decompression ensues further instability. Reconstruction of spinal column by pedicle screw and rod provide stability and prevents secondary neural damage and deformity thereby helps in early mobilization. Prospective study was done to evaluate the results in 20 cases of spinal tuberculosis in thoracolumbar region associated with neurological deficit. We operated our cases (12 males and 8 females by posterolateral decompression, fusion and stabilization by pedicle screw and rod along with antitubercular drug treatment. All patients were with neurological deficit, single level involvement and 10 to 30 degree of mild kyphosis. After surgery, kyphosis improved from 20.7 ± 5.5 degrees to 12.5 ± 3.9 degree. Bony fusion was in 65.0% cases. Neurological improvement and pain subsided in all the patients.

''The dermal internal brassiere flap,'' a new modification of inferior pedicle breast reduction technic.

Science.gov (United States)

Temel, Metin; Karakaş, Ali O; Dokuyucu, Recep; Türkmen, Arif

2015-06-01

The inferior pedicle mammaplasty is particularly applied to large breasts with a long sternal notch to nipple distance. The present study reports modifications developed to solve the bottoming-out deformity, the lack of upper pole fullness and the wound healing problems seen at the reverse T-zone, known disadvantages of the inferior pedicle reduction mammaplasty, and evaluates postoperative sensation. A total of 110 patients with a mean age of 32 underwent the same technique. In this technique, two pairs of quadrangular and triangular flaps were planned from the skin of resection sites. The triangular dermal flaps and quadrangular flaps were suspended from the periosteum of the 2nd and 4th ribs, respectively. The distance from the nipple to inframammary fold was measured at the postoperative 1st month and 1st year. In the postoperative period, a nipple-inframammary fold distance increase of over 2 cm was determined as bottoming-out deformity. Sensation evaluations were performed by subjective and objective tests. The mean sternal notch to nipple distance was 35.00 cm. After operation, the mean distance between the sternal notch and the nipple was 20.00 cm. NAC examination revealed normal sensation in all patients. Whereas the preoperative mean areolar threshold value was 36.70 g/mm(2), the postoperative first-year mean areolar pressure threshold value was 35.50 g/mm(2) (p value was 25.30 g/mm(2), whereas the postoperative first-year mean nipple pressure threshold value was 26.00 g/mm(2) (p = 0.5471). The postoperative first-month mean sternal notch to nipple distance value of the patients was 20.00 cm, whereas the postoperative first-year mean sternal notch to nipple distance value of the patients was 20.00 cm, (p = 0.0648). The postoperative first-month mean nipple to submammary fold distance value of the patients was 10.50 cm, the postoperative first-year mean nipple to submammary fold distance value of the patients was 11.00 cm (p disadvantages of the inferior

The effect of nurse navigation on timeliness of breast cancer care at an academic comprehensive cancer center.

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Basu, Mohua; Linebarger, Jared; Gabram, Sheryl G A; Patterson, Sharla Gayle; Amin, Miral; Ward, Kevin C

2013-07-15

A patient navigation process is required for accreditation by the National Accreditation Program for Breast Centers (NAPBC). Patient navigation has previously been shown to improve timely diagnosis in patients with breast cancer. This study sought to assess the effect of nurse navigation on timeliness of care following the diagnosis of breast cancer by comparing patients who were treated in a comprehensive cancer center with and without the assistance of nurse navigation. Navigation services were initiated at an NAPBC-accredited comprehensive breast center in July 2010. Two 9-month study intervals were chosen for comparison of timeliness of care: October 2009 through June 2010 and October 2010 through June 2011. All patients with breast cancer diagnosed in the cancer center with stage 0 to III disease during the 2 study periods were identified by retrospective cancer registry review. Time from diagnosis to initial oncology consultation was measured in business days, excluding holidays and weekends. Overall, 176 patients met inclusion criteria: 100 patients prior to and 76 patients following nurse navigation implementation. Nurse navigation was found to significantly shorten time to consultation for patients older than 60 years (B = -4.90, P = .0002). There was no change in timeliness for patients 31 to 60 years of age. Short-term analysis following navigation implementation showed decreased time to consultation for older patients, but not younger patients. Further studies are indicated to assess the long-term effects and durability of this quality improvement initiative. © 2013 American Cancer Society.

Indoor wayfinding and navigation

CERN Document Server

2015-01-01

Due to the widespread use of navigation systems for wayfinding and navigation in the outdoors, researchers have devoted their efforts in recent years to designing navigation systems that can be used indoors. This book is a comprehensive guide to designing and building indoor wayfinding and navigation systems. It covers all types of feasible sensors (for example, Wi-Fi, A-GPS), discussing the level of accuracy, the types of map data needed, the data sources, and the techniques for providing routes and directions within structures.

Control algorithms for autonomous robot navigation

International Nuclear Information System (INIS)

Jorgensen, C.C.

1985-01-01

This paper examines control algorithm requirements for autonomous robot navigation outside laboratory environments. Three aspects of navigation are considered: navigation control in explored terrain, environment interactions with robot sensors, and navigation control in unanticipated situations. Major navigation methods are presented and relevance of traditional human learning theory is discussed. A new navigation technique linking graph theory and incidental learning is introduced

[Effectiveness of posterior intrasegmental fixation with pedicle screw-lamina hook system in treatment of lumbar spondylolysis].

Science.gov (United States)

Zhou, Zhongjie; Song, Yueming; Zeng, Jiancheng; Liu, Hao; Liu, Limin; Kong, Qingquan; Li, Tao; Gong, Quan

2013-03-01

To investigate the effectiveness of posterior intrasegmental fixation with pedicle screw-lamina hook system and bone grafting for lumbar spondylolysis. Between January 2005 and October 2009, 22 patients with lumbar spondylolysis underwent posterior intrasegmental fixation with pedicle screw-lamina hook system and bone grafting. There were 19 males and 3 females with an average age of 18.4 years (range, 12-26 years). The main symptom was low back pain with an average disease duration of 16 months (range, 8-56 months). The visual analogue scale (VAS) was 6.0 +/- 1.2 and Oswestry disability index (ODI) was 72.0% +/- 10.0% preoperatively. The X-ray films showed bilateral spondylolysis at L4 in 9 cases and at L5 in 13 cases. The range of motion (ROM) at upper and lower intervertebral spaces was (11.8 +/- 2.8) degrees and (14.1 +/- 1.9) degrees, respectively. All incisions healed by first intention. All patients were followed up 12-45 months (mean, 25 months). Low back pain was significantly alleviated after operation. The VAS score (0.3 +/- 0.5) and ODI (17.6% +/- 3.4%) were significantly decreased at last follow-up when compared with preoperative scores (P spondylolysis, having a high fusion rate, low complication rate, and maximum retention of lumbar ROM.

Pedicled Temporalis Muscle Flap for Craniofacial Reconstruction: A 35-Year Clinical Experience with 366 Flaps.

Science.gov (United States)

Spanio di Spilimbergo, Stefano; Nordera, Paolo; Mardini, Samir; Castiglione, Giusy; Chim, Harvey; Pinna, Vittore; Brunello, Massimo; Cusino, Claudio; Roberto, Squaquara; Baciliero, Ugo

2017-02-01

In the past 130 years, the temporalis muscle flap has been used for a variety of different indications. In this age of microsurgery and perforator flaps, the temporalis muscle flap still has many useful applications for craniofacial reconstruction. Three hundred sixty-six temporalis muscle flaps were performed in a single center between 1978 and 2012. The authors divided the cases into two series-before and after 1994-because, after 1994, they started to perform free flap reconstructions, and indications for reconstruction with a temporalis muscle flap were changed RESULTS:: In the series after 1994, flaps were most commonly used for reconstruction of defects in the maxilla, mandible, and oropharynx, in addition to facial reanimation and filling of orbital defects. Complications included total flap necrosis (1.6 percent) and partial flap necrosis (10.7 percent). The rate of material extrusion at the donor site decreased after porous polyethylene was uniformly used for reconstruction from 17.1 to 7.9 percent. The pedicled temporalis muscle flap continues to have many applications in craniofacial reconstruction. With increasing use of free flaps, the authors' indications for the pedicled temporalis muscle flap are now restricted to (1) orbital filling for congenital or acquired anophthalmia; (2) filling of unilateral maxillectomy defects; and (3) facial reanimation in selected cases of facial nerve palsy. Therapeutic, IV.

How assistive technology changes the brain: the critical role of hippocampal-striatal interactions during cognitive training.

Science.gov (United States)

Kéri, Szabolcs

2015-01-01

Recent studies found structural changes of the brain during cognitive training. These changes may be important when assistive technologies are used, for example, to boost memory and navigation abilities in patients with neurocognitive disorders. In this study, we show that extensive training with a platformer game simulating navigation and real-life spatial abilities, patients with Alzheimer's disease and amnestic mild cognitive impairmant exhibit an increased volume of the caudate nucleus in contrast to healthy individuals who display increased hippocampal volumes. These results raise the possibility that cognitive training and assistive technology may induce compensatory changes of brain structure in memory disorders.

[Clinical observation on laparoscopic radiofrequency ablation assisted enucleation for the renal epithelial angimyolipoma].

Science.gov (United States)

Yang, Yang; Yang, Rong; Guo, Hongqian

2014-08-13

To explore the clinicopathological characteristics of epithelial angiomyolipoma (EAML) and examine the clinical efficacy and prognosis of laparoscopic radio frequency ablation assisted enucleation. The clinicopathological data of 7 patients with renal EAML undergoing laparoscopic radio frequency ablation assisted enucleation were reviewed from April 2009 to June 2012. And the clinical efficacy and prognosis of laparoscopic radio frequency ablation assisted enucleation were analyzed. Laparoscopic radio frequency ablation assisted enucleation was successfully performed in all cases without postoperative bleeding, ureteral obstruction, chronic renal insufficiency or urinary leakage. The mean operative duration was 110 min. Renal pedicles were blocked in 4 patients with a mean blockage time of 9 min. The mean intraoperative bleeding was 90 ml. No blood transfusion was required. The absolute bedrest time was 1-3 days and the drainage tube implanted for 3.8 days. Postoperative pathology showed that all cases were EAML. Immunohistochemistry showed HMB-45⁺ and small muscle action⁺ and creatine kinase⁻ in epithelioid cells. During a mean follow-up period of 1.8 years, none of them had local tumor recurrence, chronic renal insufficiency or other complications. Renal EAML is a rare subtype of angiomyolipoma without specific clinical and imaging features. And its definite confirmation depends on pathology. Laparoscopic radio frequency ablation assisted enucleation is both safe and effective in the treatment of renal EAML with pseudocapsule.

Treatment of degenerative lumbar spondylolisthesis by using minimally invasive transforaminal lumbar interbody fusion and percutaneous pedicle screw fixation

Directory of Open Access Journals (Sweden)

Hao WU

2016-04-01

Full Text Available Objective To discuss clinical therapeutic effects of minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF combined with percutaneous pedicle screw fixation for degenerative lumbar spondylolisthesis (DLS.  Methods A total of 32 DLS patients treated by MIS-TLIF and percutaneous pedicle screw fixation from January 2013 to September 2015 in Xuanwu Hospital, Capital Medical University were retrospectively reviewed. Visual Analogue Scale (VAS, Oswestry Disability Index (ODI and Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36 scores were assessed and compared between preoperation and one week, 3 months after operation and in the last follow-up. Lumbar lordosis angle, coronal Cobb angle, coronal and sagittal body shifting, complication, the degree of spondylolisthesis (Meyerding classification and the rate of spondylolisthesis were measured according to preoperative and postoperative spinal X-ray examination. Fusion rate was evaluated according to X-rays or CT in the last follow-up, and MRI was used to assess the degree of decompression.  Results Thirty-two patients were under test with mean operation time 160 min, intraoperative blood loss 120 ml, postoperative hospital stay 7.22 d and follow-up 10.83 months. Decompression and fusion levels ranged from L2-S1 and interbody fusion was performed in 32 patients and 41 levels were fused. Compared with preoperation, the VAS and ODI scores were significantly increased at one week, 3 months after operation and in the last follow-up (P = 0.000, for all, while SF-36 score (P = 0.002, 0.000, 0.000, lumbar lordotic angle (P = 0.000, for all, coronal Cobb angle (P = 0.000, for all and slippage rate (P = 0.000, for all were significantly decreased. The fusion rate was 92.22%, and the improvement rate of ODI was (80.51 ± 6.02% in the last follow-up. There were 3 cases appeared complications, including one case of infection and 2 cases of cerebrospinal fluid (CSF fistula, and were

A Leapfrog Navigation System

Science.gov (United States)

Opshaug, Guttorm Ringstad

There are times and places where conventional navigation systems, such as the Global Positioning System (GPS), are unavailable due to anything from temporary signal occultations to lack of navigation system infrastructure altogether. The goal of the Leapfrog Navigation System (LNS) is to provide localized positioning services for such cases. The concept behind leapfrog navigation is to advance a group of navigation units teamwise into an area of interest. In a practical 2-D case, leapfrogging assumes known initial positions of at least two currently stationary navigation units. Two or more mobile units can then start to advance into the area of interest. The positions of the mobiles are constantly being calculated based on cross-range distance measurements to the stationary units, as well as cross-ranges among the mobiles themselves. At some point the mobile units stop, and the stationary units are released to move. This second team of units (now mobile) can then overtake the first team (now stationary) and travel even further towards the common goal of the group. Since there always is one stationary team, the position of any unit can be referenced back to the initial positions. Thus, LNS provides absolute positioning. I developed navigation algorithms needed to solve leapfrog positions based on cross-range measurements. I used statistical tools to predict how position errors would grow as a function of navigation unit geometry, cross-range measurement accuracy and previous position errors. Using this knowledge I predicted that a 4-unit Leapfrog Navigation System using 100 m baselines and 200 m leap distances could travel almost 15 km before accumulating absolute position errors of 10 m (1sigma). Finally, I built a prototype leapfrog navigation system using 4 GPS transceiver ranging units. I placed the 4 units in the vertices a 10m x 10m square, and leapfrogged the group 20 meters forwards, and then back again (40 m total travel). Average horizontal RMS position

Using Frames and JavaScript To Automate Teacher-Side Web Page Navigation for Classroom Presentations.

Science.gov (United States)

Snyder, Robin M.

HTML provides a platform-independent way of creating and making multimedia presentations for classroom instruction and making that content available on the Internet. However, time in class is very valuable, so that any way to automate or otherwise assist the presenter in Web page navigation during class can save valuable seconds. This paper…

Results of triple muscle (sartorius, tensor fascia latae and part of gluteus medius pedicle bone grafting in neglected femoral neck fracture in physiologically active patients

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Pankaj Kumar Mishra

2014-01-01

Full Text Available Background: Femoral neck fractures are notorious for complications like avascular necrosis and nonunion. In developing countries, various factors such as illiteracy, low socioeconomic status, ignorance are responsible for the delay in surgery. Neglected fracture neck femur always poses a formidable challenge. The purpose of this study was to evaluate the results of triple muscle pedicle bone grafting using sartorius, tensor fasciae latae and part of gluteus medius in neglected femoral neck fracture. Materials and Methods: This is a retrospective study with medical record of 50 patients, who were operated by open reduction, internal fixation along with muscle pedicle bone grafting by the anterior approach. After open reduction, two to three cancellous screws (6.5 mm were used for internal fixation in all cases. A bony chunk of the whole anterior superior iliac spine of 1 cm thickness, 1 cm width and 4.5 cm length, taken from the iliac crest comprised of muscle pedicle of sartorius, tensor fascia latae and part of gluteus medius. Then the graft with all three muscles mobilized and put in the trough made over the anterior or anterosuperior aspect of the femoral head. The graft was fixed with one or two 4.5 mm self-tapping cortical screw in anterior to posterior direction. Results: 14 patients were lost to followup. The results were based on 36 patients. We observed that in our series, there was union in 34, out of 36 (94.4% patients. All patients were within the age group of 15-51 years (average 38 years with displaced neglected femoral neck fracture of ≥30 days. Mean time taken for full clinicoradiological union was 14 weeks (range-10-24 weeks. Conclusion: Triple muscle pedicle bone grafting gives satisfactory results for neglected femoral neck fracture in physiologically active patients.

[Free tissue transfers with lengthening of vascular pedicle using interpositional vein grafts. About 10 cases].

Science.gov (United States)

Yeo, S; Perrot, P; Duteille, F

2010-04-01

The realization of free flaps with lack of reliable vessels nearby the loss of substance is a difficult problem for plastic surgeons. We report 10 cases of free tissue transfers with a one-stage technique lengthening the vascular pedicle of the free flap with interpositional vein grafts. Taking into consideration the good results and the low rate of morbidity, the authors emphasize the use of this technique rather than a two-stage procedure. Copyright 2009 Elsevier Masson SAS. All rights reserved.

Pedicled rectus abdominis muscle and fascia flap sling the bulbar urethra for treatment for male-acquired urinary incontinence: report of ten cases.

Science.gov (United States)

Xu, Yue-Min; Zhang, Xin-Ru; Xie, Hong; Song, Lu-Jie; Feng, Chao; Fei, Xiao-Fang

2014-03-01

Male urinary incontinence is relatively common complication of radical prostatectomy and of posterior urethroplasty following traumatic pelvic fracture. Here, we investigate the use of pedicled rectus abdominis muscle and fascia flap sling of the bulbar urethra for treatment for male-acquired urinary incontinence. Ten patients with acquired urinary incontinence were included in the study. Urinary incontinence was secondary to TURP in three patients and was secondary to posterior urethroplasty performed following traumatic pelvic fracture in seven patients. Pedicled rectus abdominalis muscle and fascial flaps, approximately 2.5 cm wide and 15 cm long, were isolated. The flaps were inserted into a perineal incision through a subcutaneous tunnel. The free end of the flap was sectioned to form two muscle strips, each 3 cm in length, and inserted into the space between bulbar urethra and corpus cavernosa. After adequate sling tension had been achieved, the two strips of muscle were anastomosed around the bulbar urethra using a 2-zero polyglactin suture. The patients were followed up for between 12 and 82 months (mean 42.8 months). Complete continence was achieved with good voiding in seven of the 10 patients. In other three patients achieved good voiding following catheter removal, but incontinence was only moderately improved. A pedicled rectus muscle fascial sling of the bulbar urethra is an effective and safe treatment for male patients with mild to moderate acquired urinary incontinence, but it may not be suitable for severe incontinence or for patients with weak rectus abdominalis muscles.

A BLE-Based Pedestrian Navigation System for Car Searching in Indoor Parking Garages.

Science.gov (United States)

Wang, Sheng-Shih

2018-05-05

The continuous global increase in the number of cars has led to an increase in parking issues, particularly with respect to the search for available parking spaces and finding cars. In this paper, we propose a navigation system for car owners to find their cars in indoor parking garages. The proposed system comprises a car-searching mobile app and a positioning-assisting subsystem. The app guides car owners to their cars based on a “turn-by-turn” navigation strategy, and has the ability to correct the user’s heading orientation. The subsystem uses beacon technology for indoor positioning, supporting self-guidance of the car-searching mobile app. This study also designed a local coordinate system to support the identification of the locations of parking spaces and beacon devices. We used Android as the platform to implement the proposed car-searching mobile app, and used Bytereal HiBeacon devices to implement the proposed positioning-assisting subsystem. We also deployed the system in a parking lot in our campus for testing. The experimental results verified that the proposed system not only works well, but also provides the car owner with the correct route guidance information.

A celestial assisted INS initialization method for lunar explorers.

Science.gov (United States)

Ning, Xiaolin; Wang, Longhua; Wu, Weiren; Fang, Jiancheng

2011-01-01

The second and third phases of the Chinese Lunar Exploration Program (CLEP) are planning to achieve Moon landing, surface exploration and automated sample return. In these missions, the inertial navigation system (INS) and celestial navigation system (CNS) are two indispensable autonomous navigation systems which can compensate for limitations in the ground based navigation system. The accurate initialization of the INS and the precise calibration of the CNS are needed in order to achieve high navigation accuracy. Neither the INS nor the CNS can solve the above problems using the ground controllers or by themselves on the lunar surface. However, since they are complementary to each other, these problems can be solved by combining them together. A new celestial assisted INS initialization method is presented, in which the initial position and attitude of the explorer as well as the inertial sensors' biases are estimated by aiding the INS with celestial measurements. Furthermore, the systematic error of the CNS is also corrected by the help of INS measurements. Simulations show that the maximum error in position is 300 m and in attitude 40″, which demonstrates this method is a promising and attractive scheme for explorers on the lunar surface.

Optimal motion planning using navigation measure

Science.gov (United States)

Vaidya, Umesh

2018-05-01

We introduce navigation measure as a new tool to solve the motion planning problem in the presence of static obstacles. Existence of navigation measure guarantees collision-free convergence at the final destination set beginning with almost every initial condition with respect to the Lebesgue measure. Navigation measure can be viewed as a dual to the navigation function. While the navigation function has its minimum at the final destination set and peaks at the obstacle set, navigation measure takes the maximum value at the destination set and is zero at the obstacle set. A linear programming formalism is proposed for the construction of navigation measure. Set-oriented numerical methods are utilised to obtain finite dimensional approximation of this navigation measure. Application of the proposed navigation measure-based theoretical and computational framework is demonstrated for a motion planning problem in a complex fluid flow.

Integrated navigation method of a marine strapdown inertial navigation system using a star sensor

International Nuclear Information System (INIS)

Wang, Qiuying; Diao, Ming; Gao, Wei; Zhu, Minghong; Xiao, Shu

2015-01-01

This paper presents an integrated navigation method of the strapdown inertial navigation system (SINS) using a star sensor. According to the principle of SINS, its own navigation information contains an error that increases with time. Hence, the inertial attitude matrix from the star sensor is introduced as the reference information to correct the SINS increases error. For the integrated navigation method, the vehicle’s attitude can be obtained in two ways: one is calculated from SINS; the other, which we have called star sensor attitude, is obtained as the product between the SINS position and the inertial attitude matrix from the star sensor. Therefore, the SINS position error is introduced in the star sensor attitude error. Based on the characteristics of star sensor attitude error and the mathematical derivation, the SINS navigation errors can be obtained by the coupling calculation between the SINS attitude and the star sensor attitude. Unlike several current techniques, the navigation process of this method is non-radiating and invulnerable to jamming. The effectiveness of this approach was demonstrated by simulation and experimental study. The results show that this integrated navigation method can estimate the attitude error and the position error of SINS. Therefore, the SINS navigation accuracy is improved. (paper)

The pedicled omentoplasty and split skin graft (POSSG) for reconstruction of large chest wall defects. A validity study of 34 patients

NARCIS (Netherlands)

C.M.E. Contant; A.N. van Geel (Albert); B. van der Holt (Bronno); T. Wiggers (Theo)

1996-01-01

textabstractThe aim of this study was to evaluate retrospectively the results of pedicled omentoplasty and split skin graft (POSSG) in reconstructing (full thickness) chest wall defects, and to define its role as a palliative procedure for local symptom control. Thirty-four patients with recurrent

Clinical efficacy of bone cement injectable pedicle screw system combined with intervertebral fusion in treatment of lumbar spondylolysis and osteoporosis

Directory of Open Access Journals (Sweden)

Peng-yi DAI

2016-10-01

Full Text Available Objective 　To observe the therapeutic effect of bone cement injectable pedicle screw system combined with intervertebral fusion for lumbar spondylolysis and osteoporosis. Methods 　The clinical data were analyzed retrospectively of 21 patients with lumbar spondylolysis and osteoporosis who received treatment of bone cement injectable pedicle screw system and intervertebral fusion from Aug. 2013 to Nov. 2015. The 21 patients (9 males and 12 females aged from 60 to 80 years (mean 64 years old; 6 of them presented degenerative spondylolysis, 15 with isthmic spondylolisthesis; 2 cases had I degree slippage, 13 had Ⅱdegree slippage, 6 had Ⅲdegree slippage, and all the cases were unisegmental slippage including 9 cases in L4 and 12 cases in L5. Bone mineral density of lumbar vertebrae (L2-L5 was measured with dual-energy X-ray absorptiometry, and T values conforming to the diagnostic criteria of osteoporosis were less than or equal to -2.5; All patients were operated with whole lamina resection for decompression, bone cement injectable pedicle screws system implantation, propped open reduction and fixation intervertebral fusion. The clinical outcomes were determined by the radiographic evaluation including intervertebral height, height of intervertebral foramen, slip distance, slip rate and slip angle, and Oswestry disability index (ODI on preoperative, 3 months after operation and the end of the time, and the interbody fusion were followed up. Results 　Cerebrospinal fluid leakage of incision was observed in two cases after operation, compression and dressing to incision, Trendelenburg position, dehydration and other treatments were taken, and the stitches of incisions were taken out on schedule. Slips in the 21 patients were reset to different extent, and lumbar physiological curvatures were recovered. The intervertebral height and height of intervertebral foramen were obviously higher 3 months after operation than that before operation (P0

[Basic concept in computer assisted surgery].

Science.gov (United States)

Merloz, Philippe; Wu, Hao

2006-03-01

To investigate application of medical digital imaging systems and computer technologies in orthopedics. The main computer-assisted surgery systems comprise the four following subcategories. (1) A collection and recording process for digital data on each patient, including preoperative images (CT scans, MRI, standard X-rays), intraoperative visualization (fluoroscopy, ultrasound), and intraoperative position and orientation of surgical instruments or bone sections (using 3D localises). Data merging based on the matching of preoperative imaging (CT scans, MRI, standard X-rays) and intraoperative visualization (anatomical landmarks, or bone surfaces digitized intraoperatively via 3D localiser; intraoperative ultrasound images processed for delineation of bone contours). (2) In cases where only intraoperative images are used for computer-assisted surgical navigation, the calibration of the intraoperative imaging system replaces the merged data system, which is then no longer necessary. (3) A system that provides aid in decision-making, so that the surgical approach is planned on basis of multimodal information: the interactive positioning of surgical instruments or bone sections transmitted via pre- or intraoperative images, display of elements to guide surgical navigation (direction, axis, orientation, length and diameter of a surgical instrument, impingement, etc. ). And (4) A system that monitors the surgical procedure, thereby ensuring that the optimal strategy defined at the preoperative stage is taken into account. It is possible that computer-assisted orthopedic surgery systems will enable surgeons to better assess the accuracy and reliability of the various operative techniques, an indispensable stage in the optimization of surgery.

[Treatment of avascular necrosis of femoral head after femoral neck fracture with pedicled iliac bone graft].

Science.gov (United States)

Wang, Benjie; Zhao, Dewei; Guo, Lin; Yang, Lei; Li, Zhigang; Cui, Daping; Tian, Fengde; Liu, Baoyi

2011-05-01

To explore the effectiveness of pedicled iliac bone graft transposition for treatment of avascular necrosis of femoral head (ANFH) after femoral neck fracture. Between June 2002 and December 2006, 22 cases (22 hips, 16 left hips and 6 right hips) of ANFH after femoral neck fracture were treated with iliac bone graft pedicled with ascending branch of the lateral femoral circumflex vessels. There were 18 males and 4 females with an age range from 28 to 48 years (mean, 37.5 years). The time from injury to internal fixation was 2-31 days, and all fractures healed within 12 months after internal fixation. The ANFH was diagnosed at 15-40 months (mean, 22 months) after internal fixation. The ANFH duration was 3-11 months (mean, 8 months). According to Association Research Circulation Osseous (ARCO) staging system, 2 hips were classified as stage IIa, 3 hips as stage IIb, 3 hips as stage IIc, 3 hips as stage IIIa, 7 hips as stage IIIb, and 4 hips as stage IIIc. The preoperative Harris hip score (HHS) was 64.10 +/- 5.95. All incisions healed by first intention and the patients had no complication of lung embolism, sciatic nerve injury, lower limb deep venous thrombosis, and numbness and pain of donor site. All patients were followed up 2.5 to 6.3 years (mean, 4.8 years). The fracture healing time was 8-12 months, and no femoral neck fracture recurred. The HHS was 90.20 +/- 5.35 at last follow-up, showing significant difference when compared with the preoperative value (t = -18.447, P = 0.000). The hip function were excellent in 11 hips, good in 10 hips, fair in 1 hip, and the excellent and good rate was 95.5%. Four hips were radiographically progressed in ARCO staging, 18 hips remained stable with a stable rate of 81.8%. Pedicled iliac bone graft transposition is an ideal option for treatment of ANFH after internal fixation of femoral neck fracture for the advantages of femoral head revascularization, sufficient cancellous bone supply, and relatively simple procedure.

Modified frontolateral partial laryngectomy operation: combined muscle-pedicle hyoid bone and thyrohyoid membrane flap in laryngeal reconstruction

OpenAIRE

Ouyang, Dian; Liu, Tian-Run; Chen, Yan-Feng; Wang, Jian

2013-01-01

Objective Laryngeal reconstruction is needed to preserve laryngeal function in patients who have undergone extensive vertical or frontal partial laryngectomy. However, the procedure remains a difficult challenge. Several reconstruction techniques have been described, but these techniques pose risks of complications such as laryngeal stenosis. This study aimed to evaluate the postoperative course and functional outcomes of a new technique that combined a muscle-pedicle hyoid bone and a thyrohy...

Segmental vs non-segmental thoracic pedicle screws constructs in adolescent idiopathic scoliosis: is there any implant alloy effect?

Science.gov (United States)

Di Silvestre, Mario; Bakaloudis, Georgeous; Ruosi, Carlo; Pipola, Valerio; Colella, Gianluca; Greggi, Tiziana; Ruffilli, Alberto; Vommaro, Francesco

2017-10-01

The aim of this study is to understand how many anchor sites are necessary to obtain maximum posterior correction of idiopathic scoliotic curve and if the alloy of instrumentation, stainless steel or titanium, may have a role in the percent of scoliosis correction. We reviewed 143 consecutive patients, affected by AIS (Lenke 1-2), who underwent a posterior spinal fusion with pedicle screw-only instrumentation between 2002 and 2005. According to the implant density and alloy used we divided the cohort in four groups. All 143 patients were reviewed at an average follow-up of 7, 2 years, the overall final main thoracic curve correction averaged 61.4%, whereas the implant density within the major curve averaged 71%. A significant correlation was observed between final% MT correction and preoperative MT flexibility and implant density. When stainless steel instrumentation is used non-segmental pedicle screw constructs seem to be equally effective as segmental instrumentations in obtaining satisfactory results in patients with main thoracic AIS. When the implant alloy used is titanium one, an implant density of ≥60% should be guaranteed to achieve similar results.

Endoscopic combined “transseptal/transnasal” approach for pituitary adenoma: reconstruction of skull base using pedicled nasoseptal flap in 91 consecutive cases

Directory of Open Access Journals (Sweden)

Yasunori Fujimoto

2015-07-01

Full Text Available Objective The purpose of this study was to describe the endoscopic combined “transseptal/transnasal” approach with a pedicled nasoseptal flap for pituitary adenoma and skull base reconstruction, especially with respect to cerebrospinal fluid (CSF fistula.Method Ninety-one consecutive patients with pituitary adenomas were retrospectively reviewed. All patients underwent the endoscopic combined “transseptal/transnasal” approach by the single team including the otorhinolaryngologists and neurosurgeons. Postoperative complications related to the flap were analyzed.Results Intra- and postoperative CSF fistulae were observed in 36 (40% and 4 (4.4% patients, respectively. Among the 4 patients, lumbar drainage and bed rest healed the CSF fistula in 3 patients and reoperation for revision was necessary in one patient. Other flap-related complications included nasal bleeding in 3 patients (3.3%.Conclusion The endoscopic combined “transseptal/transnasal” approach is most suitable for a two-surgeon technique and a pedicled nasoseptal flap is a reliable technique for preventing postoperative CSF fistula in pituitary surgery.

Lunar Navigation Architecture Design Considerations

Science.gov (United States)

D'Souza, Christopher; Getchius, Joel; Holt, Greg; Moreau, Michael

2009-01-01

The NASA Constellation Program is aiming to establish a long-term presence on the lunar surface. The Constellation elements (Orion, Altair, Earth Departure Stage, and Ares launch vehicles) will require a lunar navigation architecture for navigation state updates during lunar-class missions. Orion in particular has baselined earth-based ground direct tracking as the primary source for much of its absolute navigation needs. However, due to the uncertainty in the lunar navigation architecture, the Orion program has had to make certain assumptions on the capabilities of such architectures in order to adequately scale the vehicle design trade space. The following paper outlines lunar navigation requirements, the Orion program assumptions, and the impacts of these assumptions to the lunar navigation architecture design. The selection of potential sites was based upon geometric baselines, logistical feasibility, redundancy, and abort support capability. Simulated navigation covariances mapped to entry interface flightpath- angle uncertainties were used to evaluate knowledge errors. A minimum ground station architecture was identified consisting of Goldstone, Madrid, Canberra, Santiago, Hartebeeshoek, Dongora, Hawaii, Guam, and Ascension Island (or the geometric equivalent).

Modified frontolateral partial laryngectomy operation: combined muscle-pedicle hyoid bone and thyrohyoid membrane flap in laryngeal reconstruction

International Nuclear Information System (INIS)

Ouyang, Dian; Liu, Tian-Run; Chen, Yan-Feng; Wang, Jian

2013-01-01

Laryngeal reconstruction is needed to preserve laryngeal function in patients who have undergone extensive vertical or frontal partial laryngectomy. However, the procedure remains a difficult challenge. Several reconstruction techniques have been described, but these techniques pose risks of complications such as laryngeal stenosis. This study aimed to evaluate the postoperative course and functional outcomes of a new technique that combined a muscle-pedicle hyoid bone and a thyrohyoid flap during laryngeal reconstruction after tumor resection. Four patients underwent extensive vertical partial or frontal partial laryngectomy for cancer. After tumor resection, laryngeal reconstruction was performed using the proposed technique. Postoperative recovery time, complications, and oncologic results were evaluated. The four patients were successfully treated with the proposed technique. No dyspnea, dysphagia, or death occurred during the postoperative course. Decannulation was performed after a median of 3 days. The average postoperative hospital stay was 7 days. Short-term postoperative functional recovery was normal. No laryngeal stenosis or tumor recurrence was observed in any of the four patients after a follow-up period of more than 24 months. The combination of the muscle-pedicle hyoid bone and the thyrohyoid flap is a reliable procedure for laryngeal reconstruction after extensive vertical partial or frontal partial laryngectomy

Clinical study on minimally invasive transforaminal lumbar interbody fusion combined with percutaneous pedicle screw fixation for degenerative lumbar scoliosis

Directory of Open Access Journals (Sweden)

Hao WU

2016-04-01

Full Text Available Objective To discuss the operative essentials and therapeutic effects of minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF combined with percutaneous pedicle screw fixation for degenerative lumbar scoliosis (DLS.  Methods A total of 17 DLS patients without prior spinal diseases were treated by MIS-TLIF and percutaneous pedicle screw fixation from January 2013 to September 2015 in Xuanwu Hospital, Capital Medical University. The operation time, intraoperative blood loss, hospital stay, and postoperative complication were recorded in each patient. Visual Analogue Scale (VAS and Oswestry Disability Index (ODI were used to evaluate postoperative improvement of low back and leg pain, and clinical effects were assessed according to Medical Outcome Study 36-Item Short-Form Health Survey (SF-36. Coronal Cobb angle, sagittal lordosis angle and spinal deviation distances on coronal and sagittal plane were measured before operation, one week, 3 months after operation and in the last follow-up in spinal full-length X-ray examination. Fusion rate was calculated according to X-ray or CT scan, and the degree of decompression was evaluated by MRI.  Results Decompression and fusion levels ranged from T12-S1 vertebrae, and interbody fusion was performed in 17 patients and 56 levels were fused. Average operation time was 200 min (180-300 min, intraoperative blood loss was 320 ml (200-1000 ml and hospital stay was 8.21 d (5-12 d. All patients were followed-up for 12.13 months (5-24 months. Compared with preoperation, VAS (P = 0.000, for all and ODI scores (P = 0.000, for all decreased significantly, SF-36 score increased (P = 0.000, for all, coronal Cobb angle (P = 0.000, for all, sagittal lordosis angle (P = 0.000, for all, coronal and sagittal deviation (P = 0.000, for all decreased significantly one week and 3 months after operation and in the last follow-up. The improvement rate of ODI was (86.51 ± 6.02%, fusion rate of vertebral bodies

E-navigation Services for Non-SOLAS Ships

Directory of Open Access Journals (Sweden)

Kwang An

2016-06-01

Full Text Available It is clearly understood that the main benefits of e-navigation are improved safety and better protection of the environment through the promotion of standards of navigational system and a reduction in human error. In order to meet the expectations on the benefit of e-navigation, e-navigation services should be more focused on non-SOLAS ships. The purpose of this paper is to present necessary e-navigation services for non-SOLAS ships in order to prevent marine accidents in Korean coastal waters. To meet the objectives of the study, an examination on the present navigation and communication system for non-SOLAS ships was performed. Based on the IMO's e-navigation Strategy Implementation Plan (SIP and Korea's national SIP for e-navigation, future trends for the development and implementation of e-navigation were discussed. Consequently, Electronic Navigational Chart (ENC download and ENC up-date service, ENC streaming service, route support service and communication support service based on Maritime Cloud were presented as essential e-navigation services for non-SOLAS ships. This study will help for the planning and designing of the Korean e-navigation system. It is expected that the further researches on the navigation support systems based on e-navigation will be carried out in order to implement the essential e-navigation services for non-SOLAS ships.

BIOMECHANICAL INDICES OF STANDING AND GAIT IN PATIENTS AFTER TOTAL KNEE REPLACEMENT USING COMPUTER NAVIGATION

Directory of Open Access Journals (Sweden)

Y. A. Bezgodkov

2011-01-01

Full Text Available Several biomechanical parameters of standing and walking in 50 patients with osteoarthrosis after total knee arthroplasty were evaluated. The patients were randomly divided in two equal groups: in the first group the surgery was performed with computer navigation system and in the second - with traditional instruments. After TKA with computer navigation centers of common body pressure and legs pressure during standing phase improved significantly better than in traditional group. Walking parameters like step length, ground contact time and rhythm coefficient improved in both groups of patients but without significant difference. Thereby more precise orientation of implant that achieved during computer assisted TKA leads to better functional performance at 6 and 12 month after surgery.

Uncertainties in Navigation of Elderly People in Towns - the Assistant Project

Science.gov (United States)

Kainz, W.; Kalian, K.

2013-05-01

The ASSISTANT project contributes to maintaining the mobility of older people in Europe, in order to safeguard their social and economic participation in an increasingly ageing society. It does this by helping them to travel safely and independently by public transport. This three-year project develops an application for the home PC and smartphone that designed to help older travelers to plan their public transport journeys and then receive guidance during their journey. This guidance will help them to find the vehicle they need, warn them when to get off, when and where to change to another route, and will provide assistance if something goes wrong. There are several stages in the guidance where uncertainties play a major role and have an effect on the quality of the trip. The major uncertainty is with the location services when GPS reception in poor or impossible due to urban canyons or the user being under ground or in a tunnel. In addition, when waiting at a stop where for instance several buses might arrive at the same time, it could be difficult to identify the correct bus to board. This paper explains the overall design of the ASSISTANT project and addresses some of the issues related to positional uncertainties.

Information Fields Navigation with Piece-Wise Polynomial Approximation for High-Performance OFDM in WSNs

Directory of Open Access Journals (Sweden)

Wei Wei

2013-01-01

Full Text Available Since Wireless sensor networks (WSNs are dramatically being arranged in mission-critical applications,it changes into necessary that we consider application requirements in Internet of Things. We try to use WSNs to assist information query and navigation within a practical parking spaces environment. Integrated with high-performance OFDM by piece-wise polynomial approximation, we present a new method that is based on a diffusion equation and a position equation to accomplish the navigation process conveniently and efficiently. From the point of view of theoretical analysis, our jobs hold the lower constraint condition and several inappropriate navigation can be amended. Information diffusion and potential field are introduced to reach the goal of accurate navigation and gradient descent method is applied in the algorithm. Formula derivations and simulations manifest that the method facilitates the solution of typical sensor network configuration information navigation. Concurrently, we also treat channel estimation and ICI mitigation for very high mobility OFDM systems, and the communication is between a BS and mobile target at a terrible scenario. The scheme proposed here combines the piece-wise polynomial expansion to approximate timevariations of multipath channels. Two near symbols are applied to estimate the first-and second-order parameters. So as to improve the estimation accuracy and mitigate the ICI caused by pilot-aided estimation, the multipath channel parameters were reestimated in timedomain employing the decided OFDM symbol. Simulation results show that this method would improve system performance in a complex environment.

Indoor navigation by image recognition

Science.gov (United States)

Choi, Io Teng; Leong, Chi Chong; Hong, Ka Wo; Pun, Chi-Man

2017-07-01

With the progress of smartphones hardware, it is simple on smartphone using image recognition technique such as face detection. In addition, indoor navigation system development is much slower than outdoor navigation system. Hence, this research proves a usage of image recognition technique for navigation in indoor environment. In this paper, we introduced an indoor navigation application that uses the indoor environment features to locate user's location and a route calculating algorithm to generate an appropriate path for user. The application is implemented on Android smartphone rather than iPhone. Yet, the application design can also be applied on iOS because the design is implemented without using special features only for Android. We found that digital navigation system provides better and clearer location information than paper map. Also, the indoor environment is ideal for Image recognition processing. Hence, the results motivate us to design an indoor navigation system using image recognition.

Wireless Phone Threat Assessment for Aircraft Communication and Navigation Radios

Science.gov (United States)

Nguyens, T. X.; Koppen, S. V.; Smith, L. J.; Williams, R. A.; Salud, M. T.

2005-01-01

Emissions in aircraft communication and navigation bands are measured for the latest generation of wireless phones. The two wireless technologies considered, GSM/GPRS and CDMA2000, are the latest available to general consumers in the U.S. A base-station simulator is used to control the phones. The measurements are conducted using reverberation chambers, and the results are compared against FCC and aircraft installed equipment emission limits. The results are also compared against baseline emissions from laptop computers and personal digital assistant devices that are currently allowed to operate on aircraft.

A pilot study of the utility of a laboratory-based spinal fixation training program for neurosurgical residents.

Science.gov (United States)

Sundar, Swetha J; Healy, Andrew T; Kshettry, Varun R; Mroz, Thomas E; Schlenk, Richard; Benzel, Edward C

2016-05-01

OBJECTIVE Pedicle and lateral mass screw placement is technically demanding due to complex 3D spinal anatomy that is not easily visualized. Neurosurgical and orthopedic surgery residents must be properly trained in such procedures, which can be associated with significant complications and associated morbidity. Current training in pedicle and lateral mass screw placement involves didactic teaching and supervised placement in the operating room. The objective of this study was to assess whether teaching residents to place pedicle and lateral mass screws using navigation software, combined with practice using cadaveric specimens and Sawbones models, would improve screw placement accuracy. METHODS This was a single-blinded, prospective, randomized pilot study with 8 junior neurosurgical residents and 2 senior medical students with prior neurosurgery exposure. Both the study group and the level of training-matched control group (each group with 4 level of training-matched residents and 1 senior medical student) were exposed to a standardized didactic education regarding spinal anatomy and screw placement techniques. The study group was exposed to an additional pilot program that included a training session using navigation software combined with cadaveric specimens and accessibility to Sawbones models. RESULTS A statistically significant reduction in overall surgical error was observed in the study group compared with the control group (p = 0.04). Analysis by spinal region demonstrated a significant reduction in surgical error in the thoracic and lumbar regions in the study group compared with controls (p = 0.02 and p = 0.04, respectively). The study group also was observed to place screws more optimally in the cervical, thoracic, and lumbar regions (p = 0.02, p = 0.04, and p = 0.04, respectively). CONCLUSIONS Surgical resident education in pedicle and lateral mass screw placement is a priority for training programs. This study demonstrated that compared with a

Navigation Lights - USACE IENC

Data.gov (United States)

Department of Homeland Security — These inland electronic Navigational charts (IENCs) were developed from available data used in maintenance of Navigation channels. Users of these IENCs should be...

Surface navigation on Mars with a Navigation Satellite

Science.gov (United States)

Vijayaraghavan, A.; Thurman, Sam W.; Kahn, Robert D.; Hastrup, Rolf C.

Radiometric navigation data from the Deep Space Network (DSN) stations on the earth to transponders and other surface elements such as rovers and landers on Mars, can determine their positions to only within a kilometer in inertial space. The positional error is mostly in the z-component of the surface element parallel to the Martian spin-axis. However, with Doppler and differenced-Doppler data from a Navigation Satellite in orbit around Mars to two or more of such transponders on the planetary surface, their positions can be determined to within 15 meters (or 20 meters for one-way Doppler beacons on Mars) in inertial space. In this case, the transponders (or other vehicles) on Mars need not even be capable of directly communicating to the earth. When the Navigation Satellite data is complemented by radiometric observations from the DSN stations also, directly to the surface elements on Mars, their positions can be determined to within 3 meters in inertial space. The relative positions of such surface elements on Mars (relative to one another) in Mars-fixed coordinates, however, can be determined to within 5 meters from simply range and Doppler data from the DSN stations to the surface elements. These results are obtained from covariance studies assuming X-band data noise levels and data-arcs not exceeding 10 days. They are significant in the planning and deployment of a Mars-based navigation network necessary to support real-time operations during critical phases of manned exploration of Mars.

A Celestial Assisted INS Initialization Method for Lunar Explorers

Directory of Open Access Journals (Sweden)

Jiancheng Fang

2011-07-01

Full Text Available The second and third phases of the Chinese Lunar Exploration Program (CLEP are planning to achieve Moon landing, surface exploration and automated sample return. In these missions, the inertial navigation system (INS and celestial navigation system (CNS are two indispensable autonomous navigation systems which can compensate for limitations in the ground based navigation system. The accurate initialization of the INS and the precise calibration of the CNS are needed in order to achieve high navigation accuracy. Neither the INS nor the CNS can solve the above problems using the ground controllers or by themselves on the lunar surface. However, since they are complementary to each other, these problems can be solved by combining them together. A new celestial assisted INS initialization method is presented, in which the initial position and attitude of the explorer as well as the inertial sensors’ biases are estimated by aiding the INS with celestial measurements. Furthermore, the systematic error of the CNS is also corrected by the help of INS measurements. Simulations show that the maximum error in position is 300 m and in attitude 40″, which demonstrates this method is a promising and attractive scheme for explorers on the lunar surface.

THE ADOPTION STAGES OF MOBILE NAVIGATION TECHNOLOGY WAZE APP AS JAKARTA TRAFFIC JAM SOLUTION

Directory of Open Access Journals (Sweden)

NONI NOERKAISAR

2016-09-01

Full Text Available This study analyzes the adoption stages of Waze mobile navigation by using a hierarchy of effects models AIDA. Data were obtained through the survey method by means of direct interview using questionnaire instrument assistance. The results showed that there were two groups, one who have already used the Waze application and the other who have not yet used Waze application. The two groups were analyzed to see a series of Waze application adoption process. It can be seen that each stage in the adoption process affects each other. The interest of respondents to the Waze app is affected by the strengthening of awareness regarding the benefits offered by mobile navigation app Waze. The high interest of resondents continues to stage where the respondents are interested in using Waze application. At the final stage it is known that the majority of respondents who were exposed to information on uses and functions of the application Waze are willing to immediately adopt the Waze app as a mobile navigation application while driving

Semiotic resources for navigation

DEFF Research Database (Denmark)

Due, Brian Lystgaard; Lange, Simon Bierring

2018-01-01

This paper describes two typical semiotic resources blind people use when navigating in urban areas. Everyone makes use of a variety of interpretive semiotic resources and senses when navigating. For sighted individuals, this especially involves sight. Blind people, however, must rely on everything...... else than sight, thereby substituting sight with other modalities and distributing the navigational work to other semiotic resources. Based on a large corpus of fieldwork among blind people in Denmark, undertaking observations, interviews, and video recordings of their naturally occurring practices...... of walking and navigating, this paper shows how two prototypical types of semiotic resources function as helpful cognitive extensions: the guide dog and the white cane. This paper takes its theoretical and methodological perspective from EMCA multimodal interaction analysis....

CARS 2008: Computer Assisted Radiology and Surgery. Proceedings

Energy Technology Data Exchange (ETDEWEB)

NONE

2008-06-15

The proceedings contain contributions to the following topics: digital imaging, computed tomography, magnetic resonance, cardiac and vascular imaging, computer assisted radiation therapy, image processing and display, minimal invasive spinal surgery, computer assisted treatment of the prostate, the interventional radiology suite of the future, interventional oncology, computer assisted neurosurgery, computer assisted head and neck and ENT surgery, cardiovascular surgery, computer assisted orthopedic surgery, image processing and visualization, surgical robotics, instrumentation and navigation, surgical modelling, simulation and education, endoscopy and related techniques, workflow and new concepts in surgery, research training group 1126: intelligent surgery, digital operating room, image distribution and integration strategies, regional PACS and telemedicine, PACS - beyond radiology and E-learning, workflow and standardization, breast CAD, thoracic CAD, abdominal CAD, brain CAD, orthodontics, dentofacial orthopedics and airways, imaging and treating temporomandibular joint conditions, maxillofacial cone beam CT, craniomaxillofacial image fusion and CBCT incidental findings, image guided craniomaxillofacial procedures, imaging as a biomarker for therapy response, computer aided diagnosis. The Poster sessions cover the topics computer aided surgery, Euro PACS meeting, computer assisted radiology, computer aided diagnosis and computer assisted radiology and surgery.

CARS 2008: Computer Assisted Radiology and Surgery. Proceedings

International Nuclear Information System (INIS)

2008-01-01

The proceedings contain contributions to the following topics: digital imaging, computed tomography, magnetic resonance, cardiac and vascular imaging, computer assisted radiation therapy, image processing and display, minimal invasive spinal surgery, computer assisted treatment of the prostate, the interventional radiology suite of the future, interventional oncology, computer assisted neurosurgery, computer assisted head and neck and ENT surgery, cardiovascular surgery, computer assisted orthopedic surgery, image processing and visualization, surgical robotics, instrumentation and navigation, surgical modelling, simulation and education, endoscopy and related techniques, workflow and new concepts in surgery, research training group 1126: intelligent surgery, digital operating room, image distribution and integration strategies, regional PACS and telemedicine, PACS - beyond radiology and E-learning, workflow and standardization, breast CAD, thoracic CAD, abdominal CAD, brain CAD, orthodontics, dentofacial orthopedics and airways, imaging and treating temporomandibular joint conditions, maxillofacial cone beam CT, craniomaxillofacial image fusion and CBCT incidental findings, image guided craniomaxillofacial procedures, imaging as a biomarker for therapy response, computer aided diagnosis. The Poster sessions cover the topics computer aided surgery, Euro PACS meeting, computer assisted radiology, computer aided diagnosis and computer assisted radiology and surgery

33 CFR 401.54 - Interference with navigation aids.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Interference with navigation aids. 401.54 Section 401.54 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION... with navigation aids. (a) Aids to navigation shall not be interfered with or used as moorings. (b) No...

An additional reference axis improves femoral rotation alignment in image-free computer navigation assisted total knee arthroplasty.

Science.gov (United States)

Inui, Hiroshi; Taketomi, Shuji; Nakamura, Kensuke; Sanada, Takaki; Tanaka, Sakae; Nakagawa, Takumi

2013-05-01

Few studies have demonstrated improvement in accuracy of rotational alignment using image-free navigation systems mainly due to the inconsistent registration of anatomical landmarks. We have used an image-free navigation for total knee arthroplasty, which adopts the average algorithm between two reference axes (transepicondylar axis and axis perpendicular to the Whiteside axis) for femoral component rotation control. We hypothesized that addition of another axis (condylar twisting axis measured on a preoperative radiograph) would improve the accuracy. One group using the average algorithm (double-axis group) was compared with the other group using another axis to confirm the accuracy of the average algorithm (triple-axis group). Femoral components were more accurately implanted for rotational alignment in the triple-axis group (ideal: triple-axis group 100%, double-axis group 82%, P<0.05). Copyright © 2013 Elsevier Inc. All rights reserved.

A UHF RFID positioning system for use in warehouse navigation by employees with cognitive disability.

Science.gov (United States)

Gunther, Eric J M; Sliker, Levin J; Bodine, Cathy

2017-11-01

Unemployment among the almost 5 million working-age adults with cognitive disabilities in the USA is a costly problem in both tax dollars and quality of life. Job coaching is an effective tool to overcome this, but the cost of job coaching services sums with every new employee or change of employment roles. There is a need for a cost-effective, automated alternative to job coaching that incurs a one-time cost and can be reused for multiple employees or roles. An effective automated job coach must be aware of its location and the location of destinations within the job site. This project presents a design and prototype of a cart-mounted indoor positioning and navigation system with necessary original software using Ultra High Frequency Radio Frequency Identification (UHF RFID). The system presented in this project for use within a warehouse setting is one component of an automated job coach to assist in the job of order filler. The system demonstrated accuracy to within 0.3 m under the correct conditions with strong potential to serve as the basis for an effective indoor navigation system to assist warehouse workers with disabilities. Implications for rehabilitation An automated job coach could improve employability of and job retention for people with cognitive disabilities. An indoor navigation system using ultra high frequency radio frequency identification was proposed with an average positioning accuracy of 0.3 m. The proposed system, in combination with a non-linear context-aware prompting system, could be used as an automated job coach for warehouse order fillers with cognitive disabilities.

Accuracy of percutaneous pedicle screws for thoracic and lumbar spine fractures compared with open technique.

Science.gov (United States)

Paredes, Igor; Panero, Irene; Cepeda, Santiago; Castaño-Leon, Ana M; Jimenez-Roldan, Luis; Perez-Nuñez, Ángel; Alén, Jose A; Lagares, Alfonso

2018-06-14

This study aimed to compare the accuracy of screw placement between open pedicle screw fixation and percutaneous pedicle screw fixation (MIS) for the treatment of thoracolumbar spine fractures (TSF). Forty-nine patients with acute TSF who were treated with transpedicular screw fixation from January 2013 to December 2016 were retrospectively reviewed. The patients were divided into Open and MIS groups. Laminectomy was performed in either group if needed. The accuracy of the screw placement, the evolution of the Cobb sagital angle postoperatively and at 12-month follow up and the neurological status were recorded. AO type of fracture and TLICS score were also recorded. Mean age was 42 years old. Mean TLICS score was 6,29 and 5,96 for open and MIS groups respectively. Twenty five MIS and 24 open surgeries were performed, and 350 (175 in each group) screws were inserted (7,14 per patient). Twenty-four and 13 screws were considered ̈out ̈ in the open and MIS groups respectively (Odds ratio 1,98. 0,97-4,03 p=0,056). The Cobb sagittal angle went from 13,3o to 4,5o and from 14,9o to 8,2o in the Open and MIS groups respectively (both popen and MIS groups respectively. No neurological worsening was observed. For the treatment of acute thoracolumbar fractures, the MIS technique seems to achieve similar results to the open technique in relation to neurological improvement and deformity correction, while placing the screws more accurately.

Indications, Outcomes, and Complications of Pedicled Propeller Perforator Flaps for Upper Body Defects: A Systematic Review

Directory of Open Access Journals (Sweden)

Davide Lazzeri

2013-01-01

Full Text Available Background The aim of this investigation was to systematically review the current literatureto provide the best data for indications, outcomes, survival, and complication rates ofpedicled propeller perforator flaps for upper body defects.Methods A comprehensive literature review for articles published from January 1991 toDecember 2011 was performed using the PubMed, Medline, and Cochrane Databases. Articleswithout available full-text, single case reports or papers with excessive missing data wereexcluded. Papers reporting pedicle-perforator (propeller flaps used for lower extremityreconstruction were excluded from meta-analysis.Results From the initial 1,736 studies our search yielded, 343 studies qualified for the secondstage of selection. Of 117 full-text reports screened, 41 studies, met the definitive inclusionand exclusion criteria. Of the selected 41 articles, 26 were case series, original papers orretrospective reviews and were included, whereas 15 were case report papers and thereforewere excluded. Two hundred ninety-five propeller flaps were reported to have been used ina total of 283 patients. Indications include repair of trauma-induced injuries, post-traumarevision surgery, cancer resection, chronic infection, pressure sores, and chronic ulcers with amajor complication rate (3.3% comparable to that of free flaps. No specific exclusion criteriafor the procedure were presented in the studies reviewed.Conclusions Pedicled propeller flaps are a versatile and safe reconstructive option that areeasy and quick to raise and that provide unlimited clinical solutions because of the theoreticalpossibility of harvesting them based on any perforator chosen among those classified in the body.

Real-time precision pedestrian navigation solution using Inertial Navigation System and Global Positioning System

OpenAIRE

Yong-Jin Yoon; King Ho Holden Li; Jiahe Steven Lee; Woo-Tae Park

2015-01-01

Global Positioning System and Inertial Navigation System can be used to determine position and velocity. A Global Positioning System module is able to accurately determine position without sensor drift, but its usage is limited in heavily urbanized environments and heavy vegetation. While high-cost tactical-grade Inertial Navigation System can determine position accurately, low-cost micro-electro-mechanical system Inertial Navigation System sensors are plagued by significant errors. Global Po...

Community to clinic navigation to improve diabetes outcomes

Directory of Open Access Journals (Sweden)

Nancy E. Schoenberg

2017-03-01

Full Text Available Rural residents experience rates of Type 2 Diabetes Mellitus (T2DM that are considerably higher than their urban or suburban counterparts. Two primary modifiable factors, self-management and formal clinical management, have potential to greatly improve diabetes outcomes. “Community to Clinic Navigation to Improve Diabetes Outcomes,” is the first known randomized clinical trial pilot study to test a hybrid model of diabetes self-management education plus clinical navigation among rural residents with T2DM. Forty-one adults with T2DM were recruited from two federally qualified health centers in rural Appalachia from November 2014–January 2015. Community health workers provided navigation, including helping participants understand and implement a diabetes self-management program through six group sessions and, if needed, providing assistance in obtaining clinic visits (contacting providers' offices for appointments, making reminder calls, and facilitating transportation and dependent care. Pre and post-test data were collected on T2DM self-management, physical measures, demographics, psychosocial factors, and feasibility (cost, retention, and satisfaction. Although lacking statistical significance, some outcomes indicate trends in positive directions, including diet, foot care, glucose monitoring, and physical health, including decreased HbA1c and triglyceride levels. Process evaluations revealed high levels of satisfaction and feasibility. Due to the limited intervention dose, modest program expenditures (~$29,950, and a severely affected population most of whom had never received diabetes education, outcomes were not as robust as anticipated. Given high rates of satisfaction and retention, this culturally appropriate small group intervention holds promise for hard to reach rural populations. Modifications should include expanded recruitment venues, sample size, intervention dosage and longer term assessment.

HyMoTrack: A Mobile AR Navigation System for Complex Indoor Environments.

Science.gov (United States)

Gerstweiler, Georg; Vonach, Emanuel; Kaufmann, Hannes

2015-12-24

Navigating in unknown big indoor environments with static 2D maps is a challenge, especially when time is a critical factor. In order to provide a mobile assistant, capable of supporting people while navigating in indoor locations, an accurate and reliable localization system is required in almost every corner of the building. We present a solution to this problem through a hybrid tracking system specifically designed for complex indoor spaces, which runs on mobile devices like smartphones or tablets. The developed algorithm only uses the available sensors built into standard mobile devices, especially the inertial sensors and the RGB camera. The combination of multiple optical tracking technologies, such as 2D natural features and features of more complex three-dimensional structures guarantees the robustness of the system. All processing is done locally and no network connection is needed. State-of-the-art indoor tracking approaches use mainly radio-frequency signals like Wi-Fi or Bluetooth for localizing a user. In contrast to these approaches, the main advantage of the developed system is the capability of delivering a continuous 3D position and orientation of the mobile device with centimeter accuracy. This makes it usable for localization and 3D augmentation purposes, e.g. navigation tasks or location-based information visualization.

HyMoTrack: A Mobile AR Navigation System for Complex Indoor Environments

Directory of Open Access Journals (Sweden)

Georg Gerstweiler

2015-12-01

Full Text Available Navigating in unknown big indoor environments with static 2D maps is a challenge, especially when time is a critical factor. In order to provide a mobile assistant, capable of supporting people while navigating in indoor locations, an accurate and reliable localization system is required in almost every corner of the building. We present a solution to this problem through a hybrid tracking system specifically designed for complex indoor spaces, which runs on mobile devices like smartphones or tablets. The developed algorithm only uses the available sensors built into standard mobile devices, especially the inertial sensors and the RGB camera. The combination of multiple optical tracking technologies, such as 2D natural features and features of more complex three-dimensional structures guarantees the robustness of the system. All processing is done locally and no network connection is needed. State-of-the-art indoor tracking approaches use mainly radio-frequency signals like Wi-Fi or Bluetooth for localizing a user. In contrast to these approaches, the main advantage of the developed system is the capability of delivering a continuous 3D position and orientation of the mobile device with centimeter accuracy. This makes it usable for localization and 3D augmentation purposes, e.g. navigation tasks or location-based information visualization.

Navigating oceans and cultures: Polynesian and European navigation systems in the late eighteenth century

Science.gov (United States)

Walker, M.

2012-05-01

Significant differences in the rotation of the celestial dome between the tropical and temperate zones did not stop the peoples of either the tropical Pacific or temperate Europe from using geocentric astronomy to guide exploration of the oceans. Although the differences in the night sky contributed to differences between the Pacific Island and European systems for navigation at sea, the two navigation systems exhibit substantial similarities. Both systems define positions on the surface of the Earth using two coordinates that vary at right angles to each other and use stars, and to a lesser extent the sun, to determine directions. This essay explores similarities and differences in the use of geocentric astronomy for navigation at sea by the peoples of Polynesia and Europe in the late eighteenth century. Captain Cook's orders to discover the unknown southern continent after observing the transit of Venus combined with differences in language and culture to obscure the deeper similarities between the navigation systems used by Cook and the Polynesians. Although it was a further 200 years before anthropologists studied Pacific navigation, collaborations in voyaging with communities in Oceania demonstrated the effectiveness of Pacific navigation systems, revived interest in traditional voyaging in island communities around the Pacific, and potentially open the way for further collaborations in other areas.

Multi-Flight-Phase GPS Navigation Filter Applications to Terrestrial Vehicle Navigation and Positioning

Science.gov (United States)

Park, Young W.; Montez, Moises N.

1994-01-01

A candidate onboard space navigation filter demonstrated excellent performance (less than 8 meter level RMS semi-major axis accuracy) in performing orbit determination of a low-Earth orbit Explorer satellite using single-frequency real GPS data. This performance is significantly better than predicted by other simulation studies using dual-frequency GPS data. The study results revealed the significance of two new modeling approaches evaluated in the work. One approach introduces a single-frequency ionospheric correction through pseudo-range and phase range averaging implementation. The other approach demonstrates a precise axis-dependent characterization of dynamic sample space uncertainty to compute a more accurate Kalman filter gain. Additionally, this navigation filter demonstrates a flexibility to accommodate both perturbational dynamic and observational biases required for multi-flight phase and inhomogeneous application environments. This paper reviews the potential application of these methods and the filter structure to terrestrial vehicle and positioning applications. Both the single-frequency ionospheric correction method and the axis-dependent state noise modeling approach offer valuable contributions in cost and accuracy improvements for terrestrial GPS receivers. With a modular design approach to either 'plug-in' or 'unplug' various force models, this multi-flight phase navigation filter design structure also provides a versatile GPS navigation software engine for both atmospheric and exo-atmospheric navigation or positioning use, thereby streamlining the flight phase or application-dependent software requirements. Thus, a standardized GPS navigation software engine that can reduce the development and maintenance cost of commercial GPS receivers is now possible.

[Utility of nickel-titanium shape memory alloys of vertebral body reduction fixator with assisted distraction bar].

Science.gov (United States)

Man, Yi; Zheng, Yue-huan; Cao, Peng; Chen, Bo; Zheng, Tao; Sun, Chang-hui; Lu, Jiong

2011-06-07

To test the nickel-titanium (Ni-Ti) shape memory alloys of vertebral body reduction fixator with assisted distraction bar for the treatment of traumatic and osteoporotic vertebral body fracture. A Ni-Ti shape memory alloys of vertebral body reduction fixator with assisted distraction bar was implanted into the compressed fracture specimens through vertebral pedicle with the radiographic monitoring to reduce the collapsed endplate as well as distract the compressed vertebral fracture. Radiographic film and computed tomographic reconstruction technique were employed to evaluate the effects of reduction and distraction. A biomechanic test machine was used to measure the fatigue and the stability of deformation of fixation segments. Relying on the effect of temperature shape memory, such an assembly could basically reduce the collapsed endplate as well as distract the compressed vertebral fracture. And when unsatisfied results of reduction and distraction occurred, its super flexibility could provide additional distraction strength. A Ni-Ti shape memory alloys of vertebral body reduction fixator with assisted distraction bar may provide effective endplate reduction, restore the vertebral height and the immediate biomechanic spinal stability. So the above assembly is indicated for the treatment of traumatic and osteoporotic vertebral body fracture.

Substitution of the anterior cruciate ligament: a long-term histologic and biomechanical study with autogenous pedicled grafts of the iliotibial band in dogs

NARCIS (Netherlands)

Rens, van T.J.G.; Berg, van den A.F.; Huiskes, H.W.J.; Kuypers, W.

1986-01-01

This paper reports the experience with anterior cruciate ligament (ACL) substitution by standardized pedicled strips of the iliotibial band, fixed to the tibia and femur with a bone-peg fixation technique. Thirty-two young adult (± one year old) Labrador dogs were used for the experiments (58

Computer-assisted Orthopaedic Surgery: Current State and Future Perspective

Directory of Open Access Journals (Sweden)

Guoyan eZheng

2015-12-01

Full Text Available Introduced about two decades ago, computer-assisted orthopaedic surgery (CAOS has emerged as a new and independent area, due to the importance of treatment of musculoskeletal diseases in orthopaedics and traumatology, increasing availability of different imaging modalities, and advances in analytics and navigation tools. The aim of this paper is to present the basic elements of CAOS devices and to review state-of-the-art examples of different imaging modalities used to create the virtual representations, of different position tracking devices for navigation systems, of different surgical robots, of different methods for registration and referencing, and of CAOS modules that have been realized for different surgical procedures. Future perspectives will also be outlined.

HMM based automated wheelchair navigation using EOG traces in EEG

Science.gov (United States)

Aziz, Fayeem; Arof, Hamzah; Mokhtar, Norrima; Mubin, Marizan

2014-10-01

This paper presents a wheelchair navigation system based on a hidden Markov model (HMM), which we developed to assist those with restricted mobility. The semi-autonomous system is equipped with obstacle/collision avoidance sensors and it takes the electrooculography (EOG) signal traces from the user as commands to maneuver the wheelchair. The EOG traces originate from eyeball and eyelid movements and they are embedded in EEG signals collected from the scalp of the user at three different locations. Features extracted from the EOG traces are used to determine whether the eyes are open or closed, and whether the eyes are gazing to the right, center, or left. These features are utilized as inputs to a few support vector machine (SVM) classifiers, whose outputs are regarded as observations to an HMM. The HMM determines the state of the system and generates commands for navigating the wheelchair accordingly. The use of simple features and the implementation of a sliding window that captures important signatures in the EOG traces result in a fast execution time and high classification rates. The wheelchair is equipped with a proximity sensor and it can move forward and backward in three directions. The asynchronous system achieved an average classification rate of 98% when tested with online data while its average execution time was less than 1 s. It was also tested in a navigation experiment where all of the participants managed to complete the tasks successfully without collisions.

Usability Testing of Two Ambulatory EHR Navigators.

Science.gov (United States)

Hultman, Gretchen; Marquard, Jenna; Arsoniadis, Elliot; Mink, Pamela; Rizvi, Rubina; Ramer, Tim; Khairat, Saif; Fickau, Keri; Melton, Genevieve B

2016-01-01

Despite widespread electronic health record (EHR) adoption, poor EHR system usability continues to be a significant barrier to effective system use for end users. One key to addressing usability problems is to employ user testing and user-centered design. To understand if redesigning an EHR-based navigation tool with clinician input improved user performance and satisfaction. A usability evaluation was conducted to compare two versions of a redesigned ambulatory navigator. Participants completed tasks for five patient cases using the navigators, while employing a think-aloud protocol. The tasks were based on Meaningful Use (MU) requirements. The version of navigator did not affect perceived workload, and time to complete tasks was longer in the redesigned navigator. A relatively small portion of navigator content was used to complete the MU-related tasks, though navigation patterns were highly variable across participants for both navigators. Preferences for EHR navigation structures appeared to be individualized. This study demonstrates the importance of EHR usability assessments to evaluate group and individual performance of different interfaces and preferences for each design.

Development of a Three-dimensional Surgical Navigation System with Magnetic Resonance Angiography and a Three-dimensional Printer for Robot-assisted Radical Prostatectomy.

Science.gov (United States)

Jomoto, Wataru; Tanooka, Masao; Doi, Hiroshi; Kikuchi, Keisuke; Mitsuie, Chiemi; Yamada, Yusuke; Suzuki, Toru; Yamano, Toshiko; Ishikura, Reiichi; Kotoura, Noriko; Yamamoto, Shingo

2018-01-02

We sought to develop a surgical navigation system using magnetic resonance angiography (MRA) and a three-dimensional (3D) printer for robot-assisted radical prostatectomy (RARP). Six patients with pathologically proven localized prostate cancer were prospectively enrolled in this study. Prostate magnetic resonance imaging (MRI), consisting of T2-weighted sampling perfection with application-optimized contrasts using different flip-angle evolutions (SPACE) and true fast imaging with steady-state precession (true FISP), reconstructed by volume rendering, was followed by dynamic contrast-enhanced MRA performed with a volumetric interpolated breath-hold examination (VIBE) during intravenous bolus injection of gadobutrol. Images of arterial and venous phases were acquired over approximately 210 seconds. Selected images were sent to a workstation for generation of 3D volume-rendered images and standard triangulated language (STL) files for 3D print construction. The neurovascular bundles (NVBs) were found in sequence on non-contrast images. Accessory pudendal arteries (APAs) were found in all cases in the arterial phase of contrast enhancement but were ill-defined on non-contrast enhanced MRA. Dynamic contrast-enhanced MRA helped to detect APAs, suggesting that this 3D system using MRI will be useful in RARP.

75 FR 50884 - Navigation and Navigable Waters; Technical, Organizational, and Conforming Amendments, Sector...

Science.gov (United States)

2010-08-18

... 3 and 165 to reflect changes in Coast Guard internal organizational structure. Sector Portland and... 1625-ZA25 Navigation and Navigable Waters; Technical, Organizational, and Conforming Amendments, Sector... Waters; Technical, Organizational, and Conforming Amendments, Sector Columbia River.'' 2. On page 48564...

Reflecting on the tensions faced by a community-based multicultural health navigator service.

Science.gov (United States)

Henderson, Saras; Kendall, Elizabeth

2014-11-01

The community navigator model was developed to assist four culturally and linguistically diverse communities (Sudanese, Burmese, Pacific Islander Group, Afghani) in south-east Queensland to negotiate the Australian health system and promote health. Using participatory action research, we developed the model in partnership with community leaders and members, the local health department and two non-governmental organisations. Following implementation, we evaluated the model, with the results published elsewhere. However, our evaluation revealed that although the model was accepted by the communities and was associated with positive health outcomes, the financial, social and organisational durability of the model was problematic. Ironically, this situation was inadvertently created by critical decisions made during the development process to enhance the durability and acceptability of the model. This paper explores these critical decisions, our rationale for making those decisions and the four hidden tensions that subsequently emerged. Using a reflective case study method to guide our analysis, we provide possible resolutions to these tensions that may promote the longevity and utility of similar models in the future. WHAT IS KNOWN ABOUT THE TOPIC?: The use of community navigators to assist culturally diverse communities to access health services is not new. Many benefits have been documented for communities, individuals and heath service providers following the use of such models. What is not well documented is how to maintain these models in a safe and cost-effective way within the Australian health system while respecting cultural and community practices and reducing the burden of service delivery on the navigators. WHAT DOES THIS PAPER ADD?: This paper provides a perspective on how the development of community-based service models inherently places them in a position of tension that must be resolved if they are to be long lasting. Four core tensions experienced

Getting Lost Through Navigation

DEFF Research Database (Denmark)

Debus, Michael S.

2017-01-01

In this presentation, I argued two things. First, that it is navigation that lies at the core of contemporary (3D-) videogames and that its analysis is of utmost importance. Second, that this analysis needs a more rigorous differentiation between specific acts of navigation. Considering the Oxford...... in videogames is a configurational rather than an interpretational one (Eskelinen 2001). Especially in the case of game spaces, navigation appears to be of importance (Wolf 2009; Flynn 2008). Further, it does not only play a crucial role for the games themselves, but also for the experience of the player...

Inertial navigation without accelerometers

Science.gov (United States)

Boehm, M.

The Kennedy-Thorndike (1932) experiment points to the feasibility of fiber-optic inertial velocimeters, to which state-of-the-art technology could furnish substantial sensitivity and accuracy improvements. Velocimeters of this type would obviate the use of both gyros and accelerometers, and allow inertial navigation to be conducted together with vehicle attitude control, through the derivation of rotation rates from the ratios of the three possible velocimeter pairs. An inertial navigator and reference system based on this approach would probably have both fewer components and simpler algorithms, due to the obviation of the first level of integration in classic inertial navigators.

Application of an expandable pedicle screw in the severe osteoporotic spine: a preliminary study.

Science.gov (United States)

Wu, Zi-xiang; Cui, Geng; Lei, Wei; Fan, Yong; Wan, Shi-yong; Ma, Zhen-sheng; Sang, Hong-xun

2010-12-01

To investigate the clinical abstract and radiographic outcome of multi-axial expandable pedicle screws (MEPS) in patients with osteoporosis. One hundred and twenty-five consecutive patients received MEPS from the UPASS spinal fixation system to obtain thoracolumbar or lumbosacral stabilization. All patients underwent bone mineral density (BMD) scans. The indications for use of the MEPS were spinal diseases with severe osteoporosis (degenerative diseases 46 cases, compression fractures 28 cases, lumbar tuberculosis 27 cases and revision spine surgery 24 cases). The pre-operative and three months post-operative functional evaluations were graded with JOA and VAS scoring system. One week, six months and 12 months after surgery, plain film and three-dimensional CT scans were obtained to evaluate the spinal fusion and fixation effectiveness of MEPS. The mean follow-up period was 18 months (ranged from 6 to 33 months). All patients suffered from severely osteoporosis with a decrease of 25.3% in BMD. The pre-operative JOA and VAS scores were 11.3±3.0 and 6.7±1.8 mm, respectively. Three months after operation, the JOA and VAS scores were 25.2±2.0 and 2.3±1.7 mm. The recovery rate was 78.1±11.5％ and the clinical results were satisfying. There were no instances of screw loosening or pullout of the MEPS and the screw-bone interface was excellent. The radiographic results showed that bone healing, both around the screws and inter-vertebral, was achieved. In osteoporosis spine surgery, excellent bone-screw interface and fixation strength can be achieved by using MEPS. MEPS are a novel approach to increase the pedicle screw fixation in osteoporotic and revision spine surgeries.

78 FR 41304 - Navigation and Navigable Waters; Technical, Organizational, and Conforming Amendments; Correction

Science.gov (United States)

2013-07-10

... DEPARTMENT OF HOMELAND SECURITY Coast Guard 33 CFR Part 105 [Docket No. USCG-2013-0397] RIN 1625-AC06 Navigation and Navigable Waters; Technical, Organizational, and Conforming Amendments; Correction AGENCY: Coast Guard, DHS. ACTION: Final rule; correction. SUMMARY: The Coast Guard published a final rule...

Restricted Navigation Areas - USACE IENC

Data.gov (United States)

Department of Homeland Security — These inland electronic Navigational charts (IENCs) were developed from available data used in maintenance of Navigation channels. Users of these IENCs should be...

NFC Internal: An Indoor Navigation System

Science.gov (United States)

Ozdenizci, Busra; Coskun, Vedat; Ok, Kerem

2015-01-01

Indoor navigation systems have recently become a popular research field due to the lack of GPS signals indoors. Several indoors navigation systems have already been proposed in order to eliminate deficiencies; however each of them has several technical and usability limitations. In this study, we propose NFC Internal, a Near Field Communication (NFC)-based indoor navigation system, which enables users to navigate through a building or a complex by enabling a simple location update, simply by touching NFC tags those are spread around and orient users to the destination. In this paper, we initially present the system requirements, give the design details and study the viability of NFC Internal with a prototype application and a case study. Moreover, we evaluate the performance of the system and compare it with existing indoor navigation systems. It is seen that NFC Internal has considerable advantages and significant contributions to existing indoor navigation systems in terms of security and privacy, cost, performance, robustness, complexity, user preference and commercial availability. PMID:25825976

Spontaneus bilateral pedicle fracture 30 years after Harrington Instrumentation for idiopathic scoliosis: a case report

Directory of Open Access Journals (Sweden)

Obid Peter

2012-01-01

Full Text Available Abstract Introduction Spontaneous fractures of the spine are a common entity. They usually occur in older people with osteoporosis. This case is presented on account of its rarity. To the best of the authors' knowledge only one case of an osteoporotic pedicle fracture after Harrington Instrumentation has been described before. Case presentation We report the case of a 46-year-old Caucasian woman who underwent surgery due to idiopathic scoliosis with a Harrington Instrumentation (T4 to L3 30 years ago. During the operation she was infected with hepatitis C while receiving erythrocyte concentrates and has suffered from liver cirrhosis since then. She presented with a sudden pain in her lower back and paraesthesia in both her legs but no other neurological symptoms. A computed tomography scan showed a bilateral pedicle fracture of L3 and an additional compression fracture of L4. In the first session we performed a dorsal stabilization with massive intraoperative bleeding and a postoperative failure of liver synthesis. In a second session an additional ventral augmentation was done. After the second operation she developed a hepatorenal syndrome. Both operations left the patient in a very critical state which led to a prolonged stay in the intensive care and rehabilitation unit. At her 12-month follow-up visit, she was free of complaints. Conclusion The un-physiological load of the spine after Harrington Instrumentation can lead to osteoporosis due to inactivity even in younger patients. Although these implants are not used anymore one should keep this possibility in mind when dealing with patients who have received Harrington rods in surgical procedures.

75 FR 48564 - Navigation and Navigable Waters; Technical, Organizational, and Conforming Amendments, Sector...

Science.gov (United States)

2010-08-11

... DEPARTMENT OF HOMELAND SECURITY Coast Guard 33 CFR Parts 3 and 165 [Docket No. USCG-2010-0351] RIN 1625-ZA25 Navigation and Navigable Waters; Technical, Organizational, and Conforming Amendments, Sector Columbia River, WA AGENCY: Coast Guard, DHS. ACTION: Final rule. SUMMARY: This rule makes non-substantive...

Blind MuseumTourer: A System for Self-Guided Tours in Museums and Blind Indoor Navigation

Directory of Open Access Journals (Sweden)

Apostolos Meliones

2018-01-01

Full Text Available Notably valuable efforts have focused on helping people with special needs. In this work, we build upon the experience from the BlindHelper smartphone outdoor pedestrian navigation app and present Blind MuseumTourer, a system for indoor interactive autonomous navigation for blind and visually impaired persons and groups (e.g., pupils, which has primarily addressed blind or visually impaired (BVI accessibility and self-guided tours in museums. A pilot prototype has been developed and is currently under evaluation at the Tactual Museum with the collaboration of the Lighthouse for the Blind of Greece. This paper describes the functionality of the application and evaluates candidate indoor location determination technologies, such as wireless local area network (WLAN and surface-mounted assistive tactile route indications combined with Bluetooth low energy (BLE beacons and inertial dead-reckoning functionality, to come up with a reliable and highly accurate indoor positioning system adopting the latter solution. The developed concepts, including map matching, a key concept for indoor navigation, apply in a similar way to other indoor guidance use cases involving complex indoor places, such as in hospitals, shopping malls, airports, train stations, public and municipality buildings, office buildings, university buildings, hotel resorts, passenger ships, etc. The presented Android application is effectively a Blind IndoorGuide system for accurate and reliable blind indoor navigation.

Sex differences in navigation strategy and efficiency.

Science.gov (United States)

Boone, Alexander P; Gong, Xinyi; Hegarty, Mary

2018-05-22

Research on human navigation has indicated that males and females differ in self-reported navigation strategy as well as objective measures of navigation efficiency. In two experiments, we investigated sex differences in navigation strategy and efficiency using an objective measure of strategy, the dual-solution paradigm (DSP; Marchette, Bakker, & Shelton, 2011). Although navigation by shortcuts and learned routes were the primary strategies used in both experiments, as in previous research on the DSP, individuals also utilized route reversals and sometimes found the goal location as a result of wandering. Importantly, sex differences were found in measures of both route selection and navigation efficiency. In particular, males were more likely to take shortcuts and reached their goal location faster than females, while females were more likely to follow learned routes and wander. Self-report measures of strategy were only weakly correlated with objective measures of strategy, casting doubt on their usefulness. This research indicates that the sex difference in navigation efficiency is large, and only partially related to an individual's navigation strategy as measured by the dual-solution paradigm.

Celestial Navigation in the USA, Fiji, and Tunisia

Science.gov (United States)

Holbrook, Jarita C.

2015-05-01

Today there are many coastal communities that are home to navigators who use stars for position finding at night; I was, however, unaware of this fact when I began researching celestial navigation practices in 1997. My project focused on three communities: the Moce Islanders of Fiji, the Kerkennah Islanders in Tunisia, and the U.S. Navy officers and students at the United States Naval Academy, Annapolis, Maryland. My goal was to answer the question of why people continue to navigate by the stars, but also to understand the role of technology in their navigation practices. Using anthropology techniques of ethnography including participant observation, formal and informal interviews, audio and videotaping, I gathered data over five years at the three communities. I began by learning the details of how they use the stars for navigation. Next, I learned about who did the navigation and where they learned to navigate. I gathered opinions on various navigation aids and instruments, and opinions about the future of using the stars for navigation. I listened to the stories that they told about navigating. In the United States I worked in English, in Fiji, in Fijian and English, and in Tunisia, French and English. For the formal interviews I worked with translators. The navigators use stars for navigating today but the future of their techniques is not certain. Though practiced today, these celestial navigation traditions have undergone and continue to undergo changes. New navigational technologies are part of the stimulation for change, thus 'a meeting of different worlds' is symbolized by peoples encounters with these technologies.

Adolescent idiopathic scoliosis: sagital plane and low density pedicle screws

Directory of Open Access Journals (Sweden)

Rodrigo Augusto do Amaral

2014-03-01

Full Text Available OBJECTIVE: To examine the sagittal curves of patients treated with CD instrumentation using exclusively pedicle screws. METHODS: Image analysis of medical records of 27 patients (26 M and 1 F with a minimum follow-up of 6 months, who underwent surgical treatment in our service between January 2005 and December 2010. The curves were evaluated on coronal and sagittal planes, taking into account the potential correction of the technique. RESULTS: In the coronal plan the following curves were evaluated: proximal thoracic (TPx, main thoracic (TPp, and thoracolumbar; lumbar (TL, L, and the average flexibility was 52%, 52%, and 92% and the capacity of correction was 51%, 72%, and 64%, respectively. In the sagittal plane there was a mean increase in thoracic kyphosis (CT of 41% and an average reduction of lumbar lordosis (LL of 17%. Correlation analysis between variables showed Pearson coefficient of correlation of 0.053 and analysis of dispersion of R2 = <0.001. CONCLUSION: The method has shown satisfactory results with maintenance of kyphosis correction in patients with normal and hyper kyphotic deformities.

[Direct repair of adolescent lumbar spondylolysis using a pedicle screw-laminar hook system by paramedian approach].

Science.gov (United States)

Wang, Bin; Tang, Yong-hua; Tang, Hong-chao; Jin, Cai-yi

2011-08-01

To discuss the indication and clinical effect of direct repair of adolescent lumbar spondylolysis by screw-laminar hook system. From August 2003 to December 2008, 28 patients (13 males and 15 females,ranging in age from 15 and 26 years, averaged 21.6 years) with lumbar spondylolysis were treated with isthmic bone grafting and internal fixation with a pedicle screw-laminar hook system. Three patients had spondylolysis at L3, L4; 5 patients had spondylolysis at L4, L5; 8 patients had spondylolysis at L4; and 12 patients had spondylolysis at L5. All the patients had low back pain and lasted over 6 months. According to preoperative and postoperative plain radiograph, CT scan and Macnab criteria, the fusion rate and clinical effect of this technique were evaluated. All the patients were followed up with a mean period of 14.9 months, ranging from 9 to 24 months. All the patients had bony union according to the X-rays and CT scan. According to the calculation results of Macnab criteria, 22 patients got an excellent result, 5 good and 1 fair. The direct repair of adolescent lumbar spondylolysis with pedicle screw-laminar hook system can shorten length of operation,decrease blood loss, preserve more posterior structures of spine and avoid iatrogenic instability of spine. The postoperative immediate stability of vertebral segment is acquired and the mobility of adjacent intervertebral discs is reserved. The screw-laminar hook system for the treatment of adolescent spondylolisthesis can get satisfactory clinical results.

Vibrotactile Feedbacks System for Assisting the Physically Impaired Persons for Easy Navigation

Science.gov (United States)

Safa, M.; Geetha, G.; Elakkiya, U.; Saranya, D.

2018-04-01

NAYAN architecture is for a visually impaired person to help for navigation. As well known, all visually impaired people desperately requires special requirements even to access services like the public transportation. This prototype system is a portable device; it is so easy to carry in any conduction to travel through a familiar and unfamiliar environment. The system consists of GPS receiver and it can get NEMA data through the satellite and it is provided to user's Smartphone through Arduino board. This application uses two vibrotactile feedbacks that will be placed in the left and right shoulder for vibration feedback, which gives information about the current location. The ultrasonic sensor is used for obstacle detection which is found in front of the visually impaired person. The Bluetooth modules connected with Arduino board is to send information to the user's mobile phone which it receives from GPS.

Design of all-weather celestial navigation system

Science.gov (United States)

Sun, Hongchi; Mu, Rongjun; Du, Huajun; Wu, Peng

2018-03-01

In order to realize autonomous navigation in the atmosphere, an all-weather celestial navigation system is designed. The research of celestial navigation system include discrimination method of comentropy and the adaptive navigation algorithm based on the P value. The discrimination method of comentropy is studied to realize the independent switching of two celestial navigation modes, starlight and radio. Finally, an adaptive filtering algorithm based on P value is proposed, which can greatly improve the disturbance rejection capability of the system. The experimental results show that the accuracy of the three axis attitude is better than 10″, and it can work all weather. In perturbation environment, the position accuracy of the integrated navigation system can be increased 20% comparing with the traditional method. It basically meets the requirements of the all-weather celestial navigation system, and it has the ability of stability, reliability, high accuracy and strong anti-interference.

An on-line monitoring system for navigation equipment

Science.gov (United States)

Wang, Bo; Yang, Ping; Liu, Jing; Yang, Zhengbo; Liang, Fei

2017-10-01

Civil air navigation equipment is the most important infrastructure of Civil Aviation, which is closely related to flight safety. In addition to regular flight inspection, navigation equipment's patrol measuring, maintenance measuring, running measuring under special weather conditions are the important means of ensuring aviation flight safety. According to the safety maintenance requirements of Civil Aviation Air Traffic Control navigation equipment, this paper developed one on-line monitoring system with independent intellectual property rights for navigation equipment, the system breakthroughs the key technologies of measuring navigation equipment on-line including Instrument Landing System (ILS) and VHF Omni-directional Range (VOR), which also meets the requirements of navigation equipment ground measurement set by the ICAO DOC 8071, it provides technical means of the ground on-line measurement for navigation equipment, improves the safety of navigation equipment operation, and reduces the impact of measuring navigation equipment on airport operation.

32 CFR 644.3 - Navigation Projects.

Science.gov (United States)

2010-07-01

... 32 National Defense 4 2010-07-01 2010-07-01 true Navigation Projects. 644.3 Section 644.3 National... HANDBOOK Project Planning Civil Works § 644.3 Navigation Projects. (a) Land to be acquired in fee. All... construction and borrow areas. (3) In navigation-only projects, the right to permanently flood should be...

Novel free-hand T1 pedicle screw method: Review of 44 consecutive cases

Directory of Open Access Journals (Sweden)

Mark A Rivkin

2014-01-01

Full Text Available Summary of Background Data: Multilevel posterior cervical instrumented fusions are becoming more prevalent in current practice. Biomechanical characteristics of the cervicothoracic junction may necessitate extending the construct to upper thoracic segments. However, fixation in upper thoracic spine can be technically demanding owing to transitional anatomy while suboptimal placement facilitates vascular and neurologic complications. Thoracic instrumentation methods include free-hand, fluoroscopic guidance, and CT-based image guidance. However, fluoroscopy of upper thoracic spine is challenging secondary to vertebral geometry and patient positioning, while image-guided systems present substantial financial commitment and are not readily available at most centers. Additionally, imaging modalities increase radiation exposure to the patient and surgeon while potentially lengthening surgical time. Materials and Methods: Retrospective review of 44 consecutive patients undergoing a cervicothoracic fusion by a single surgeon using the novel free-hand T1 pedicle screw technique between June 2009 and November 2012. A starting point medial and cephalad to classic entry as well as new trajectory were utilized. No imaging modalities were employed during screw insertion. Postoperative CT scans were obtained on day 1. Screw accuracy was independently evaluated according to the Heary classification. Results: In total, 87 pedicle screws placed were at T1. Grade 1 placement occurred in 72 (82.8% screws, Grade 2 in 4 (4.6% screws and Grade 3 in 9 (10.3% screws. All Grade 2 and 3 breaches were <2 mm except one Grade 3 screw breaching 2-4 mm laterally. Only two screws (2.3% were noted to be Grade 4, both breaching medially by less than 2 mm. No new neurological deficits or returns to operating room took place postoperatively. Conclusions: This modification of the traditional starting point and trajectory at T1 is safe and effective. It attenuates additional bone

Compression-Based Tools for Navigation with an Image Database

Directory of Open Access Journals (Sweden)

Giovanni Motta

2012-01-01

Full Text Available We present tools that can be used within a larger system referred to as a passive assistant. The system receives information from a mobile device, as well as information from an image database such as Google Street View, and employs image processing to provide useful information about a local urban environment to a user who is visually impaired. The first stage acquires and computes accurate location information, the second stage performs texture and color analysis of a scene, and the third stage provides specific object recognition and navigation information. These second and third stages rely on compression-based tools (dimensionality reduction, vector quantization, and coding that are enhanced by knowledge of (approximate location of objects.

14 CFR 121.349 - Communication and navigation equipment for operations under VFR over routes not navigated by...

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Communication and navigation equipment for... § 121.349 Communication and navigation equipment for operations under VFR over routes not navigated by... receiver providing visual and aural signals; and (iii) One ILS receiver; and (3) Any RNAV system used to...

Quantum imaging for underwater arctic navigation

Science.gov (United States)

Lanzagorta, Marco

2017-05-01

The precise navigation of underwater vehicles is a difficult task due to the challenges imposed by the variable oceanic environment. It is particularly difficult if the underwater vehicle is trying to navigate under the Arctic ice shelf. Indeed, in this scenario traditional navigation devices such as GPS, compasses and gyrocompasses are unavailable or unreliable. In addition, the shape and thickness of the ice shelf is variable throughout the year. Current Arctic underwater navigation systems include sonar arrays to detect the proximity to the ice. However, these systems are undesirable in a wartime environment, as the sound gives away the position of the underwater vehicle. In this paper we briefly describe the theoretical design of a quantum imaging system that could allow the safe and stealthy navigation of underwater Arctic vehicles.

To the North Coast of Devon: Collaborative Navigation While Exploring Unfamiliar Terrain

Science.gov (United States)

Clancey, William J.; Lee, Pascal; Cockell, Charles S.; Braham, Stephen; Shafto, Mike

2006-01-01

Navigation-knowing where one is and finding a safe route-is a fundamental aspect of all exploration. In unfamiliar terrain, one may use maps and instruments such as a compass or binoculars to assist, and people often collaborate in finding their way. This paper analyzes a group of people driving a humvee from a base camp to the north coast of Devon Island in the High Canadian Arctic. A complete audio recording and video during most stops allows a quantitative and semantic analysis of the conversations when the team stopped to take bearings and replan a route. Over a period of 2 hours, the humvee stopped 20 times, with an average duration of 3.15 min/pause and 3.85 min moving forward. The team failed to reach its goal due to difficult terrain causing mechanical problems. The analysis attempts to explain these facts by considering a variety of complicating factors, especially the navigation problem of relating maps and the world to locate the humvee and to plan a route. The analysis reveals patterns in topic structure and turn-taking, supporting the view that the collaboration was efficient, but the tools and information were inadequate for the task. This work is relevant for planning and training for planetary surface missions, as well as developing computer systems that could aid navigation.

Autonomous Robot Navigation based on Visual Landmarks

DEFF Research Database (Denmark)

Livatino, Salvatore

2005-01-01

The use of landmarks for robot navigation is a popular alternative to having a geometrical model of the environment through which to navigate and monitor self-localization. If the landmarks are defined as special visual structures already in the environment then we have the possibility of fully a...... automatically learn and store visual landmarks, and later recognize these landmarks from arbitrary positions and thus estimate robot position and heading.......The use of landmarks for robot navigation is a popular alternative to having a geometrical model of the environment through which to navigate and monitor self-localization. If the landmarks are defined as special visual structures already in the environment then we have the possibility of fully...... autonomous navigation and self-localization using automatically selected landmarks. The thesis investigates autonomous robot navigation and proposes a new method which benefits from the potential of the visual sensor to provide accuracy and reliability to the navigation process while relying on naturally...

NFC Internal: An Indoor Navigation System

Directory of Open Access Journals (Sweden)

Busra Ozdenizci

2015-03-01

Full Text Available Indoor navigation systems have recently become a popular research field due to the lack of GPS signals indoors. Several indoors navigation systems have already been proposed in order to eliminate deficiencies; however each of them has several technical and usability limitations. In this study, we propose NFC Internal, a Near Field Communication (NFC-based indoor navigation system, which enables users to navigate through a building or a complex by enabling a simple location update, simply by touching NFC tags those are spread around and orient users to the destination. In this paper, we initially present the system requirements, give the design details and study the viability of NFC Internal with a prototype application and a case study. Moreover, we evaluate the performance of the system and compare it with existing indoor navigation systems. It is seen that NFC Internal has considerable advantages and significant contributions to existing indoor navigation systems in terms of security and privacy, cost, performance, robustness, complexity, user preference and commercial availability.

A clinical study of navigation accuracy during surgery

International Nuclear Information System (INIS)

Hirabayashi, Hidehiro; Uchiyama, Yoshitomo; Hoshida, Toru; Nakase, Hiroyuki; Morimoto, Tetsuya; Sakaki, Toshisuke

2000-01-01

It is essential to implement image-guided surgery or neuronavigation technologies that can be applied during functional surgery to localize targets accurately in the surgical field. Various navigation systems have been developed, such as the optical system and mechanical-arm-based system, to localize targets in the operative field. However, either the reference system, in optical systems, or the arm joint, in mechanical-arm-based systems, can sometimes interfere with surgical maneuvers. Therefore, we used the magnetic-force-based Computed Assisted Neurosurgery system (CANS system, Shimadzu, Co. Ltd., Kyoto, Japan) for neuronavigation. The purpose of this study was to evaluate the accuracy of the CANS navigation system. Ten patients with medically refractory epilepsy underwent implantation of subdural electrode grids to detect the epilepsy focus, and then lobectomy or multiple subpial transection was performed after informed consent was obtained. The male/female ratio was 6:4 and the mean age was 30.7 years. The CANS navigator system consists mainly of a magnetic source, a localizer probe with magnetic sensor, a three-dimensional locating measuring instrument (digitizer), an image scanner, and a personal computer. To determine the localization accuracy, the probe was moved on the subdural electrode grid which typically consists of 64 or 16 platinum-iridium electrode contacts (3 mm in the diameter) embedded in a Silastic sheet. The array of electrodes was 8 x 8 cm or 2 x 8 cm and the center-to-center inter-electrode distance was 10 mm. We evaluated the inter-electrode distances and spatial relationships among the electrodes to quantitate the precision of the probe tip localization and assumed the nasion origin reference system to assess the distribution of target coordinates. The measurement errors of each component derived from different planes for the same targets were evaluated in ten patients. The error in X-dimension ranged from 0.38 mm to 7.8 mm, the error in Y

Inland Electronic Navigational Charts (IENC)

Data.gov (United States)

Army Corps of Engineers, Department of the Army, Department of Defense — These Inland Electronic Navigational Charts (IENCs) were developed from available data used in maintenance of Navigation channels. Users of these IENCs should be...

Distally based sural neuro-fasciocutaneous perforator flap for foot and ankle reconstruction: Surgical modifications for flap pedicle and donor site closure without skin graft.

Science.gov (United States)

Chi, Zhenglin; Chen, Yiheng; Chu, Tinggang; Gao, Weiyang; Li, Zhijie; Yan, Hede; Song, Yonghuan

2018-02-01

The conventional procedure of the sural neuro-fasciocutaneous flap enables the supply of blood and venous drainage by increasing the width of the adipofascial tissue and preserving tiny venous return routes. Moreover, skin graft is a common method for donor site closure, which may lead to some complications and influence the aesthetic appearance. We report modifications for a distally based sural neuro-fasciocutaneous perforator flap and a relaying flap for donor site closure without skin graft. Twelve patients undergoing the modified flap for foot and ankle reconstruction were included in this study between 2014 and 2016. A peroneal-based perforator, a superficial vein, and the vascular axis of the sural nerve were included in the pedicle. A Z-shape skin incision was performed to explore the perforator vessels and a relaying island perforator flap was used to close the donor site. All flaps survived completely without necrosis. The area of the flaps ranged from 16 × 8 cm to 30 × 15 cm. The diameter width of the pedicle ranged from 1.0 to 2.0 cm. A relaying perforator island flap was used in 10 cases for donor site closure and no skin graft was performed. There were no serious donor site complications. All patients were satisfied with the aesthetic outcome postoperatively at the final follow-up. The distally based sural neuro-fasciocutaneous perforator flap is considered a reliable method for foot and ankle reconstruction. The modification for flap pedicle and donor site closure method without skin graft should be recommended. Copyright © 2017. Published by Elsevier Ltd.

Low Cost Integrated Navigation System for Unmanned Vessel

Directory of Open Access Journals (Sweden)

Yang Changsong

2017-11-01

Full Text Available Large errors of low-cost MEMS inertial measurement unit (MIMU lead to huge navigation errors, even wrong navigation information. An integrated navigation system for unmanned vessel is proposed. It consists of a low-cost MIMU and Doppler velocity sonar (DVS. This paper presents an integrated navigation method, to improve the performance of navigation system. The integrated navigation system is tested using simulation and semi-physical simulation experiments, whose results show that attitude, velocity and position accuracy has improved awfully, giving exactly accurate navigation results. By means of the combination of low-cost MIMU and DVS, the proposed system is able to overcome fast drift problems of the low cost IMU.

Intelligent personal navigator supported by knowledge-based systems for estimating dead reckoning navigation parameters

Science.gov (United States)

Moafipoor, Shahram

Personal navigators (PN) have been studied for about a decade in different fields and applications, such as safety and rescue operations, security and emergency services, and police and military applications. The common goal of all these applications is to provide precise and reliable position, velocity, and heading information of each individual in various environments. In the PN system developed in this dissertation, the underlying assumption is that the system does not require pre-existing infrastructure to enable pedestrian navigation. To facilitate this capability, a multisensor system concept, based on the Global Positioning System (GPS), inertial navigation, barometer, magnetometer, and a human pedometry model has been developed. An important aspect of this design is to use the human body as navigation sensor to facilitate Dead Reckoning (DR) navigation in GPS-challenged environments. The system is designed predominantly for outdoor environments, where occasional loss of GPS lock may happen; however, testing and performance demonstration have been extended to indoor environments. DR navigation is based on a relative-measurement approach, with the key idea of integrating the incremental motion information in the form of step direction (SD) and step length (SL) over time. The foundation of the intelligent navigation system concept proposed here rests in exploiting the human locomotion pattern, as well as change of locomotion in varying environments. In this context, the term intelligent navigation represents the transition from the conventional point-to-point DR to dynamic navigation using the knowledge about the mechanism of the moving person. This approach increasingly relies on integrating knowledge-based systems (KBS) and artificial intelligence (AI) methodologies, including artificial neural networks (ANN) and fuzzy logic (FL). In addition, a general framework of the quality control for the real-time validation of the DR processing is proposed, based on a

Optical augmented reality assisted navigation system for neurosurgery teaching and planning

Science.gov (United States)

Wu, Hui-Qun; Geng, Xing-Yun; Wang, Li; Zhang, Yuan-Peng; Jiang, Kui; Tang, Le-Min; Zhou, Guo-Min; Dong, Jian-Cheng

2013-07-01

This paper proposed a convenient navigation system for neurosurgeon's pre-operative planning and teaching with augmented reality (AR) technique, which maps the three-dimensional reconstructed virtual anatomy structures onto a skull model. This system included two parts, a virtual reality system and a skull model scence. In our experiment, a 73 year old right-handed man initially diagnosed with astrocytoma was selected as an example to vertify our system. His imaging data from different modalities were registered and the skull soft tissue, brain and inside vessels as well as tumor were reconstructed. Then the reconstructed models were overlayed on the real scence. Our findings showed that the reconstructed tissues were augmented into the real scence and the registration results were in good alignment. The reconstructed brain tissue was well distributed in the skull cavity. The probe was used by a neurosurgeon to explore the surgical pathway which could be directly posed into the tumor while not injuring important vessels. In this way, the learning cost for students and patients' education about surgical risks reduced. Therefore, this system could be a selective protocol for image guided surgery(IGS), and is promising for neurosurgeon's pre-operative planning and teaching.

Development of field navigation system; Field navigation system no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

Ibara, S; Minode, M; Nishioka, K [Daihatsu Motor Co. Ltd., Osaka (Japan)

1995-04-20

This paper describes the following matters on a field navigation system developed for the purpose of covering a field of several kilometer square. This system consists of a center system and a vehicle system, and the center system comprises a map information computer and a communication data controlling computer; since the accuracy for a vehicle position detected by a GPS is not sufficient, an attempt of increasing the accuracy of vehicle position detection is made by means of a hybrid system; the hybrid system uses a satellite navigation method of differential system in which the error components in the GPS are transmitted from the center, and also uses a self-contained navigation method which performs an auxiliary function when the accuracy in the GPS has dropped; corrected GPS values, emergency messages to all of the vehicles and data of each vehicle position are communicated by wireless transmission in two ways between the center and vehicles; and accommodation of the map data adopted a system that can respond quickly to any change in roads and facilities. 3 refs., 13 figs., 1 tab.

The Weatherization Assistant User's Manual (Version 8.9)

Energy Technology Data Exchange (ETDEWEB)

Gettings, Michael B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Malhotra, Mini [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ternes, Mark P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2015-01-01

The Weatherization Assistant is a Windows-based energy audit software tool that was developed by Oak Ridge National Laboratory (ORNL) to help states and their local weatherization agencies implement the U.S. Department of Energy (DOE) Weatherization Assistance Program. The Weatherization Assistant is an umbrella program for two individual energy audits or measure selection programs: the National Energy Audit Tool (NEAT) for site-built single-family homes and the Manufactured Home Energy Audit (MHEA) for mobile homes. The Weatherization Assistant User's Manual documents the operation of the user interface for Version 8.9 of the software. This includes how to install and setup the software, navigate through the program, and initiate an energy audit. All of the user interface forms associated with the software and the data fields on these forms are described in detail. The manual is intended to be a training manual for new users of the Weatherization Assistant and as a reference manual for experienced users.

Compact autonomous navigation system (CANS)

Science.gov (United States)

Hao, Y. C.; Ying, L.; Xiong, K.; Cheng, H. Y.; Qiao, G. D.

2017-11-01

Autonomous navigation of Satellite and constellation has series of benefits, such as to reduce operation cost and ground station workload, to avoid the event of crises of war and natural disaster, to increase spacecraft autonomy, and so on. Autonomous navigation satellite is independent of ground station support. Many systems are developed for autonomous navigation of satellite in the past 20 years. Along them American MANS (Microcosm Autonomous Navigation System) [1] of Microcosm Inc. and ERADS [2] [3] (Earth Reference Attitude Determination System) of Honeywell Inc. are well known. The systems anticipate a series of good features of autonomous navigation and aim low cost, integrated structure, low power consumption and compact layout. The ERADS is an integrated small 3-axis attitude sensor system with low cost and small volume. It has the Earth center measurement accuracy higher than the common IR sensor because the detected ultraviolet radiation zone of the atmosphere has a brightness gradient larger than that of the IR zone. But the ERADS is still a complex system because it has to eliminate many problems such as making of the sapphire sphere lens, birefringence effect of sapphire, high precision image transfer optical fiber flattener, ultraviolet intensifier noise, and so on. The marginal sphere FOV of the sphere lens of the ERADS is used to star imaging that may be bring some disadvantages., i.e. , the image energy and attitude measurements accuracy may be reduced due to the tilt image acceptance end of the fiber flattener in the FOV. Besides Japan, Germany and Russia developed visible earth sensor for GEO [4] [5]. Do we have a way to develop a cheaper/easier and more accurate autonomous navigation system that can be used to all LEO spacecraft, especially, to LEO small and micro satellites? To return this problem we provide a new type of the system—CANS (Compact Autonomous Navigation System) [6].

Parsimonious Ways to Use Vision for Navigation

Directory of Open Access Journals (Sweden)

Paul Graham

2012-05-01

Full Text Available The use of visual information for navigation appears to be a universal strategy for sighted animals, amongst which, one particular group of expert navigators are the ants. The broad interest in studies of ant navigation is in part due to their small brains, thus biomimetic engineers expect to be impressed by elegant control solutions, and psychologists might hope for a description of the minimal cognitive requirements for complex spatial behaviours. In this spirit, we have been taking an interdisciplinary approach to the visual guided navigation of ants in their natural habitat. Behavioural experiments and natural image statistics show that visual navigation need not depend on the remembering or recognition of objects. Further modelling work suggests how simple behavioural routines might enable navigation using familiarity detection rather than explicit recall, and we present a proof of concept that visual navigation using familiarity can be achieved without specifying when or what to learn, nor separating routes into sequences of waypoints. We suggest that our current model represents the only detailed and complete model of insect route guidance to date. What's more, we believe the suggested mechanisms represent useful parsimonious hypotheses for the visually guided navigation in larger-brain animals.

Risk management model of winter navigation operations

International Nuclear Information System (INIS)

Valdez Banda, Osiris A.; Goerlandt, Floris; Kuzmin, Vladimir; Kujala, Pentti; Montewka, Jakub

2016-01-01

The wintertime maritime traffic operations in the Gulf of Finland are managed through the Finnish–Swedish Winter Navigation System. This establishes the requirements and limitations for the vessels navigating when ice covers this area. During winter navigation in the Gulf of Finland, the largest risk stems from accidental ship collisions which may also trigger oil spills. In this article, a model for managing the risk of winter navigation operations is presented. The model analyses the probability of oil spills derived from collisions involving oil tanker vessels and other vessel types. The model structure is based on the steps provided in the Formal Safety Assessment (FSA) by the International Maritime Organization (IMO) and adapted into a Bayesian Network model. The results indicate that ship independent navigation and convoys are the operations with higher probability of oil spills. Minor spills are most probable, while major oil spills found very unlikely but possible. - Highlights: •A model to assess and manage the risk of winter navigation operations is proposed. •The risks of oil spills in winter navigation in the Gulf of Finland are analysed. •The model assesses and prioritizes actions to control the risk of the operations. •The model suggests navigational training as the most efficient risk control option.

Biomechanical comparison between titanium and cobalt chromium rods used in a pedicle subtraction osteotomy model

Directory of Open Access Journals (Sweden)

Kalpit N. Shah

2018-03-01

Full Text Available Instrumentation failure is a common complication following complex spinal reconstruction and deformity correction. Rod fracture is the most frequent mode of hardware failure and often occurs at or near a 3-column osteotomy site. Titanium (Ti rods are commonly utilized for spinal fixations, however, theoretically stiffer materials, such as cobalt-chrome (CoCr rods are also available. Despite ongoing use in clinical practice, there is little biomechanical evidence that compares the construct ability to withstand fatigue stress for Ti and Co-Cr rods. Six models using 2 polyethylene blocks each were used to simulate a pedicle subtraction osteotomy. Within each block 6.0×45 mm polyaxial screws were placed and connected to another block using either two 6.0×100 mm Ti (3 models or CoCr rods (3 models. The rods were bent to 40° using a French bender and were secured to the screws to give a vertical height of 1.5 cm between the blocks. The blocks were fatigue tested with 700N at 4 Hz until failure. The average number of cycles to failure for the Ti rod models was 12840 while the CoCr rod models failed at a significantly higher, 58351 cycles (P=0.003. All Ti models experienced rod fracture as the mode of failure. Two out of the three CoCr models had rod fractures while the last sample failed via screw fracture at the screw-tulip junction. The risk of rod failure is substantial in the setting of long segment spinal arthrodesis and corrective osteotomy. Efforts to increase the mechanical strength of posterior constructs may reduce the occurrence of this complication. Utilizing CoCr rods in patients with pedicle subtraction osteotomy may reduce the rate of device failure during maturation of the posterior fusion mass and limit the need for supplemental anterior column support.

Adaptive Landmark-Based Navigation System Using Learning Techniques

DEFF Research Database (Denmark)

Zeidan, Bassel; Dasgupta, Sakyasingha; Wörgötter, Florentin

2014-01-01

The goal-directed navigational ability of animals is an essential prerequisite for them to survive. They can learn to navigate to a distal goal in a complex environment. During this long-distance navigation, they exploit environmental features, like landmarks, to guide them towards their goal. In...... hexapod robots. As a result, it allows the robots to successfully learn to navigate to distal goals in complex environments.......The goal-directed navigational ability of animals is an essential prerequisite for them to survive. They can learn to navigate to a distal goal in a complex environment. During this long-distance navigation, they exploit environmental features, like landmarks, to guide them towards their goal....... Inspired by this, we develop an adaptive landmark-based navigation system based on sequential reinforcement learning. In addition, correlation-based learning is also integrated into the system to improve learning performance. The proposed system has been applied to simulated simple wheeled and more complex...

A navigational evaluation model for content management systems

International Nuclear Information System (INIS)

Gilani, S.; Majeed, A.

2016-01-01

Web applications are widely used world-wide, however it is important that the navigation of these websites is effective, to enhance usability. Navigation is not limited to links between pages, it is also how we complete a task. Navigational structure presented as hypertext is one of the most important component of the Web application besides content and presentation. The main objective of this paper is to explore the navigational structure of various open source Content Management Systems from the developer's perspective. For this purpose three CMS are chosen which are WordPress, Joomla, and Drupal. Objective of the research is to identify the important navigational aspects present in these CMSs. Moreover, a comparative study of these CMSs in terms of navigational support is required. For this purpose an industrial survey is conducted based on our proposed navigational evaluation model. The results shows that there exist correlation between the identified factors and these CMSs provide helpful and effective navigational support to their users. (author)

Comparison of Direct Pars Repair Techniques of Spondylolysis in Pediatric and Adolescent Patients: Pars Compression Screw Versus Pedicle Screw-Rod-Hook.

Science.gov (United States)

Karatas, Ali F; Dede, Ozgur; Atanda, Alfred A; Holmes, Larry; Rogers, Kenneth; Gabos, Peter; Shah, Suken A

2016-08-01

Retrospective clinical cohort study. To compare the clinical and radiographic outcomes of patients who were treated with intrasegmental pars fixation by either laminar compression screw (LS) or a pedicle screw, rod, and laminar hook (PSRH) construct. Spondylolysis is a nonunion defect of the pars interarticularis. In symptomatic spondylolysis, direct repair of the pars interarticularis defect can preserve motion and prevent abnormal stresses at the adjacent levels. Sixteen patients who failed nonoperative treatment and underwent direct pars repair by using LS (n=9) or PSRH (n=7) constructs were included in the study. Clinical outcome was assessed by using the MacNab criteria. Radiologic fusion and complications were evaluated using plain radiographs or computed tomography images and patient charts. The healing rate was 100% after 6 months. The healing time was similar in both the groups: LS, 6.5 months; PSRH, 6.2 months. Patients with PSRH (5.9 mo) were more likely to return to sports earlier relative to patients with LS (7.7 mo). There were no complications in the LS group; in the PSRH group, 1 patient had mild sensory deficit and 2 had superficial wound infections. The MacNab criteria for pain assessment showed an excellent or good outcome in 8 of 9 patients in LS group and 6 of 7 patients in PSRH group. Relative to LS patients, there was a significant increase in surgical time and estimated blood loss among PSRH patients. Either of the mentioned 2 techniques appears to produce acceptable results. Biplanar fluoroscopy and navigation systems could minimize the risk of screw misplacement with LS construct. Familiarity with the various fixation techniques will allow the surgeon to select the most appropriate surgical technique.

Evaluation of electrosurgery and titanium clips for ovarian pedicle haemostasis in video-assisted ovariohysterectomy with two portals in bitches

Directory of Open Access Journals (Sweden)

Rogério Luizari Guedes

Full Text Available ABSTRACT: This study evaluated the use of bipolar electrosurgery and laparoscopic clipping, and their effects on blood loss and the inflammatory response, during a two portal video-assisted ovariohysterectomy technique (two groups with 10 animals each. Surgical time and blood loss volume were significantly lower in the electrosurgery group. There were no significant changes in haematocrit between groups; however, haematocrit did differ between evaluated times, and decreased 10% from the initial measurement to four hours after the procedure. The inflammatory response was significantly higher throughout the post-surgical period, but without any different clinical signs between the two groups. Both techniques had good application for the two portal video-assisted procedure; however, the bipolar electrosurgery allowed for shorter surgical times, reduced blood loss and a minimal learning curve for the surgeon.

Vibrotactile in-vehicle navigation system

NARCIS (Netherlands)

Erp, J.B.F. van; Veen, H.J. van

2004-01-01

A vibrotactile display, consisting ofeight vibrating elements or tactors mounted in a driver's seat, was tested in a driving simulator. Participants drove with visual, tactile and multimodal navigation displays through a built-up area. Workload and the reaction time to navigation messages were

The Retrospective Analysis of Posterior Short-Segment Pedicle Instrumentation without Fusion for Thoracolumbar Burst Fracture with Neurological Deficit

Directory of Open Access Journals (Sweden)

Zhouming Deng

2014-01-01

Full Text Available This study aims to investigate the efficacy of posterior short-segment pedicle instrumentation without fusion in curing thoracolumbar burst fracture. All of the 53 patients were treated with short-segment pedicle instrumentation and laminectomy without fusion, and the restoration of retropulsed bone fragments was conducted by a novel custom-designed repositor (RRBF. The mean operation time and blood loss during surgery were analyzed; the radiological index and neurological status were compared before and after the operation. The mean operation time was 93 min (range: 62–110 min and the mean intraoperative blood loss was 452 mL in all cases. The average canal encroachment was 50.04% and 10.92% prior to the surgery and at last followup, respectively (P<0.01. The preoperative kyphotic angle was 17.2 degree (±6.87 degrees, whereas it decreased to 8.42 degree (±4.99 degrees at last followup (P<0.01. Besides, the mean vertebral body height increased from 40.15% (±9.40% before surgery to 72.34% (±12.32% at last followup (P<0.01. 45 patients showed 1-2 grades improvement in Frankel’s scale at last followup. This technique allows for satisfactory canal clearance and restoration of vertebral body height and kyphotic angle, and it may promote the recovery of neurological function. However, further research is still necessary to confirm the efficacy of this treatment.

The attack navigator

DEFF Research Database (Denmark)

Probst, Christian W.; Willemson, Jan; Pieters, Wolter

2016-01-01

The need to assess security and take protection decisions is at least as old as our civilisation. However, the complexity and development speed of our interconnected technical systems have surpassed our capacity to imagine and evaluate risk scenarios. This holds in particular for risks...... that are caused by the strategic behaviour of adversaries. Therefore, technology-supported methods are needed to help us identify and manage these risks. In this paper, we describe the attack navigator: a graph-based approach to security risk assessment inspired by navigation systems. Based on maps of a socio...

ANALYSIS OF FREE ROUTE AIRSPACE AND PERFORMANCE BASED NAVIGATION IMPLEMENTATION IN THE EUROPEAN AIR NAVIGATION SYSTEM

Directory of Open Access Journals (Sweden)

Svetlana Pavlova

2014-12-01

Full Text Available European Air Traffic Management system requires continuous improvements as air traffic is increasingday by day. For this purpose it was developed by international organizations Free Route Airspace and PerformanceBased Navigation concepts that allow to offer a required level of safety, capacity, environmental performance alongwith cost-effectiveness. The aim of the article is to provide detailed analysis of Free Route Airspace and PerformanceBased Navigation implementation status within European region including Ukrainian air navigation system.

Double Back Cut in Post-mastectomy Breast Skin (Fish-Shaped Skin Paddle) in Delayed Pedicled TRAM Flap Breast Reconstruction.

Science.gov (United States)

Berezovsky, Alexander Bogdanov; Pagkalos, Vasileios A; Shoham, Yaron; Krieger, Yuval; Silberstein, Eldad

2015-08-01

Breast reconstruction has become standard of care for female patients with breast cancer. The transverse rectus abdominis musculo-cutaneous flap (TRAMf) is the most common method of immediate or delayed autologous breast reconstruction following mastectomy. We share our experience with modified, double back cut of post-mastectomy skin in delayed pedicled TRAMf breast reconstruction, resulting in fish-shaped skin paddle. This sort of back cut is a simple, reliable way to obtain a natural, esthetically pleasant breast mound with inconspicuous hidden scars.

SLS Model Based Design: A Navigation Perspective

Science.gov (United States)

Oliver, T. Emerson; Anzalone, Evan; Park, Thomas; Geohagan, Kevin

2018-01-01

The SLS Program has implemented a Model-based Design (MBD) and Model-based Requirements approach for managing component design information and system requirements. This approach differs from previous large-scale design efforts at Marshall Space Flight Center where design documentation alone conveyed information required for vehicle design and analysis and where extensive requirements sets were used to scope and constrain the design. The SLS Navigation Team is responsible for the Program-controlled Design Math Models (DMMs) which describe and represent the performance of the Inertial Navigation System (INS) and the Rate Gyro Assemblies (RGAs) used by Guidance, Navigation, and Controls (GN&C). The SLS Navigation Team is also responsible for navigation algorithms. The navigation algorithms are delivered for implementation on the flight hardware as a DMM. For the SLS Block 1B design, the additional GPS Receiver hardware model is managed as a DMM at the vehicle design level. This paper describes the models, and discusses the processes and methods used to engineer, design, and coordinate engineering trades and performance assessments using SLS practices as applied to the GN&C system, with a particular focus on the navigation components.

Management of Anterior Abdominal Wall Defect Using a Pedicled Tensor Fascia Lata Flap: A Case Report

Directory of Open Access Journals (Sweden)

K. D. Ojuka

2012-01-01

Full Text Available Degloving injuries to anterior abdominal wall are rare due to the mechanism of injury. Pedicled tensor fascia lata is known to be a versatile flap with ability to reach the lower anterior abdomen. A 34-year-old man who was involved in a road traffic accident presented with degloving injury and defect at the left inguinal region, sigmoid colon injury, and scrotal bruises. At investigation, he was found to have pelvic fracture. The management consisted of colostomy and tensor fascia lata to cover the defect at reversal. Though he developed burst abdomen on fifth postoperative day, the flap healed with no complications.

Applications of navigation for orthognathic surgery.

Science.gov (United States)

Bobek, Samuel L

2014-11-01

Stereotactic surgical navigation has been used in oral and maxillofacial surgery for orbital reconstruction, reduction of facial fractures, localization of foreign bodies, placement of implants, skull base surgery, tumor removal, temporomandibular joint surgery, and orthognathic surgery. The primary goals in adopting intraoperative navigation into these different surgeries were to define and localize operative anatomy, to localize implant position, and to orient the surgical wound. Navigation can optimize the functional and esthetic outcomes in patients with dentofacial deformities by identifying pertinent anatomic structures, transferring the surgical plan to the patient, and verifying the surgical result. This article discusses the principles of navigation-guided orthognathic surgery. Copyright © 2014 Elsevier Inc. All rights reserved.

Collective navigation of complex networks: Participatory greedy routing.

Science.gov (United States)

Kleineberg, Kaj-Kolja; Helbing, Dirk

2017-06-06

Many networks are used to transfer information or goods, in other words, they are navigated. The larger the network, the more difficult it is to navigate efficiently. Indeed, information routing in the Internet faces serious scalability problems due to its rapid growth, recently accelerated by the rise of the Internet of Things. Large networks like the Internet can be navigated efficiently if nodes, or agents, actively forward information based on hidden maps underlying these systems. However, in reality most agents will deny to forward messages, which has a cost, and navigation is impossible. Can we design appropriate incentives that lead to participation and global navigability? Here, we present an evolutionary game where agents share the value generated by successful delivery of information or goods. We show that global navigability can emerge, but its complete breakdown is possible as well. Furthermore, we show that the system tends to self-organize into local clusters of agents who participate in the navigation. This organizational principle can be exploited to favor the emergence of global navigability in the system.

Navigating the fifth dimension: new concepts in interactive multimodality and multidimensional image navigation

Science.gov (United States)

Ratib, Osman; Rosset, Antoine; Dahlbom, Magnus; Czernin, Johannes

2005-04-01

Display and interpretation of multi dimensional data obtained from the combination of 3D data acquired from different modalities (such as PET-CT) require complex software tools allowing the user to navigate and modify the different image parameters. With faster scanners it is now possible to acquire dynamic images of a beating heart or the transit of a contrast agent adding a fifth dimension to the data. We developed a DICOM-compliant software for real time navigation in very large sets of 5 dimensional data based on an intuitive multidimensional jog-wheel widely used by the video-editing industry. The software, provided under open source licensing, allows interactive, single-handed, navigation through 3D images while adjusting blending of image modalities, image contrast and intensity and the rate of cine display of dynamic images. In this study we focused our effort on the user interface and means for interactively navigating in these large data sets while easily and rapidly changing multiple parameters such as image position, contrast, intensity, blending of colors, magnification etc. Conventional mouse-driven user interface requiring the user to manipulate cursors and sliders on the screen are too cumbersome and slow. We evaluated several hardware devices and identified a category of multipurpose jogwheel device that is used in the video-editing industry that is particularly suitable for rapidly navigating in five dimensions while adjusting several display parameters interactively. The application of this tool will be demonstrated in cardiac PET-CT imaging and functional cardiac MRI studies.

Undertapping of Lumbar Pedicle Screws Can Result in Tapping With a Pitch That Differs From That of the Screw, Which Decreases Screw Pullout Force.

Science.gov (United States)

Bohl, Daniel D; Basques, Bryce A; Golinvaux, Nicholas S; Toy, Jason O; Matheis, Erika A; Bucklen, Brandon S; Grauer, Jonathan N

2015-06-15

Survey of spine surgeons and biomechanical comparison of screw pullout forces. To investigate what may be a suboptimal practice regularly occurring in spine surgery. In order for a tap to function in its intended manner, the pitch of the tap should be the same as the pitch of the screw. Undertapping has been shown to increase the pullout force of pedicle screws compared with line-to-line tapping. However, given the way current commercial lumbar pedicle screw systems are designed, undertapping may result in a tap being used that has a different pitch from that of the screw (incongruent pitch). A survey asked participants questions to estimate the proportion of cases each participant performed in the prior year using various hole preparation techniques. Participant responses were interpreted in the context of manufacturing specifications of specific instrumentation systems. Screw pullout forces were compared between undertapping with incongruent pitch and undertapping with congruent pitch using 0.16 g/cm polyurethane foam block and 6.5-mm screws. Of the 3679 cases in which participants reported tapping, participants reported line-to-line tapping in 209 cases (5%), undertapping with incongruent pitch in 1156 cases (32%), and undertapping with congruent pitch in 2314 cases (63%). The mean pullout force for undertapping with incongruent pitch was 56 N (8%) less than the mean pullout force for undertapping with congruent pitch. This is equivalent to 13 lb. This study estimates that for about 1 out of every 3 surgical cases with tapping of lumbar pedicle screws in the United States, hole preparation is being performed by undertapping with incongruent pitch. This study also shows that undertapping with incongruent pitch results in a decrease in pullout force by 8% compared with undertapping with congruent pitch. Steps should be taken to correct this suboptimal practice. 3.

Patient-specific instrumentation for total knee arthroplasty does not match the pre-operative plan as assessed by intra-operative computer-assisted navigation.

Science.gov (United States)

Scholes, Corey; Sahni, Varun; Lustig, Sebastien; Parker, David A; Coolican, Myles R J

2014-03-01

The introduction of patient-specific instruments (PSI) for guiding bone cuts could increase the incidence of malalignment in primary total knee arthroplasty. The purpose of this study was to assess the agreement between one type of patient-specific instrumentation (Zimmer PSI) and the pre-operative plan with respect to bone cuts and component alignment during TKR using imageless computer navigation. A consecutive series of 30 femoral and tibial guides were assessed in-theatre by the same surgeon using computer navigation. Following surgical exposure, the PSI cutting guides were placed on the joint surface and alignment assessed using the navigation tracker. The difference between in-theatre data and the pre-operative plan was recorded and analysed. The error between in-theatre measurements and pre-operative plan for the femoral and tibial components exceeded 3° for 3 and 17% of the sample, respectively, while the error for total coronal alignment exceeded 3° for 27% of the sample. The present results indicate that alignment with Zimmer PSI cutting blocks, assessed by imageless navigation, does not match the pre-operative plan in a proportion of cases. To prevent unnecessary increases in the incidence of malalignment in primary TKR, it is recommended that these devices should not be used without objective verification of alignment, either in real-time or with post-operative imaging. Further work is required to identify the source of discrepancies and validate these devices prior to routine use. II.

Target relative navigation results from hardware-in-the-loop tests using the sinplex navigation system

NARCIS (Netherlands)

Steffes, S.; Dumke, M.; Heise, D.; Sagliano, M.; Samaan, M.; Theil, S.; Boslooper, E.C.; Oosterling, J.A.J.; Schulte, J.; Skaborn, D.; Söderholm, S.; Conticello, S.; Esposito, M.; Yanson, Y.; Monna, B.; Stelwagen, F.; Visee, R.

2014-01-01

The goal of the SINPLEX project is to develop an innovative solution to significantly reduce the mass of the navigation subsystem for exploration missions which include landing and/or rendezvous and capture phases. The system mass is reduced while still maintaining good navigation performance as

Time and Motion Study of a Community Patient Navigator

Directory of Open Access Journals (Sweden)

Sara S. Phillips

2014-04-01

Full Text Available Research on patient navigation has focused on validating the utility of navigators by defining their roles and analyzing their effects on patient outcomes, patient satisfaction, and cost effectiveness. Patient navigators are increasingly used outside the research context, and their roles without research responsibilities may look very different. This pilot study captured the activities of a community patient navigator for uninsured women with a positive screening test for breast cancer, using a time and motion approach over a period of three days. We followed the actions of this navigator minute by minute to assess the relative ratios of actions performed and to identify areas for time efficiency improvement to increase direct time with patients. This novel approach depicts the duties of a community patient navigator no longer fettered by navigation logs, research team meetings, surveys, and the consent process. We found that the community patient navigator was able to spend more time with patients in the clinical context relative to performing paperwork or logging communication with patients as a result of her lack of research responsibilities. By illuminating how community patient navigation functions as separate from the research setting, our results will inform future hiring and training of community patient navigators, system design and operations for improving the efficiency and efficacy of navigators, and our understanding of what community patient navigators do in the absence of research responsibilities.

Mandible vertical height correction using lingual bone-split pedicle onlay graft technique

Directory of Open Access Journals (Sweden)

Coen Pramono D

2006-09-01

Full Text Available As edentulous mandible become atrophic, a denture bearing area will also be reduced. Difficulty in the removable prosthesis rehabilitation will be present as well. The purpose of this paper reports an innovative surgical technique to cope a problem of unstable complete lower denture due to bone atrophy and resulted of vertical height reduction of the anterior region of the mandible necessary for denture retention. Vertical advancement of the lower jaw using lingual bone split pedicle onlay graft technique in the anterior region of the mandible and followed by secondary epithelization vestibuloplasty in achieving the vertical height dimension. The surgery was achieved satisfactorily as the vertical dimension of the mandible anterior region had increased and the denture seated more stable comparing with the previous denture worn by the patient. It concluded that the surgery was achieved with a great result as the vertical height of the anterior region of the mandible had increased positively therefore lead the denture seated more stable.

[epiDRB--a new minimally invasive concept for referencing in the field of computer-assisted orthopaedic surgery].

Science.gov (United States)

Ohnsorge, J A K; Weisskopf, M; Siebert, C H

2005-01-01

Optoelectronic navigation for computer-assisted orthopaedic surgery (CAOS) is based on a firm connection of bone with passive reflectors or active light-emitting diodes in a specific three-dimensional pattern. Even a so-called "minimally-invasive" dynamic reference base (DRB) requires fixation with screws or clamps via incision of the skin. Consequently an originally percutaneous intervention would unnecessarily be extended to an open procedure. Thus, computer-assisted navigation is rarely applied. Due to their tree-like design most DRB's interfere with the surgeon's actions and therefore are at permanent risk to be accidentally dislocated. Accordingly, the optic communication between the camera and the operative site may repeatedly be interrupted. The aim of the research was the development of a less bulky, more comfortable, stable and safely trackable device that can be fixed truly percutaneously. With engineering support of the industrial partner the radiolucent epiDRB was developed. It can be fixed with two or more pins and gains additional stability from its epicutaneous position. The intraoperative applicability and reliability was experimentally tested. Its low centre of gravity and its flat design allow the device to be located directly in the area of interest. Thanks to its epicutaneous position and its particular shape the epiDRB may perpetually be tracked by the navigation system without hindering the surgeon's actions. Hence, the risk of being displaced by accident is minimised and the line of sight remains unaffected. With the newly developed epiDRB computer-assisted navigation becomes easier and safer to handle even in punctures and other percutaneous procedures at the spine as much as at the extremities without an unproportionate amount of additional trauma. Due to the special design referencing of more than one vertebral body is possible at one time, thus decreasing radiation exposure and increasing efficiency.

Optical surgical navigation system causes pulse oximeter malfunction.

Science.gov (United States)

Satoh, Masaaki; Hara, Tetsuhito; Tamai, Kenji; Shiba, Juntaro; Hotta, Kunihisa; Takeuchi, Mamoru; Watanabe, Eiju

2015-01-01

An optical surgical navigation system is used as a navigator to facilitate surgical approaches, and pulse oximeters provide valuable information for anesthetic management. However, saw-tooth waves on the monitor of a pulse oximeter and the inability of the pulse oximeter to accurately record the saturation of a percutaneous artery were observed when a surgeon started an optical navigation system. The current case is thought to be the first report of this navigation system interfering with pulse oximetry. The causes of pulse jamming and how to manage an optical navigation system are discussed.

33 CFR 117.458 - Inner Harbor Navigation Canal, New Orleans.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Inner Harbor Navigation Canal, New Orleans. 117.458 Section 117.458 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF... Harbor Navigation Canal, New Orleans. (a) The draws of the SR 46 (St. Claude Avenue) bridge, mile 0.5...

33 CFR 209.170 - Violations of laws protecting navigable waters.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Violations of laws protecting navigable waters. 209.170 Section 209.170 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF... navigable waters. (a) [Reserved] (b) Injuries to Government works. Section 14 of the River and Harbor Act of...

Fault-tolerant and Diagnostic Methods for Navigation

DEFF Research Database (Denmark)

Blanke, Mogens

2003-01-01

to diagnose faults and autonomously provide valid navigation data, disregarding any faulty sensor data and use sensor fusion to obtain a best estimate for users. This paper discusses how diagnostic and fault-tolerant methods are applicable in marine systems. An example chosen is sensor fusion for navigation......Precise and reliable navigation is crucial, and for reasons of safety, essential navigation instruments are often duplicated. Hardware redundancy is mostly used to manually switch between instruments should faults occur. In contrast, diagnostic methods are available that can use analytic redundancy...

Navigating ‘riskscapes’

DEFF Research Database (Denmark)

Gee, Stephanie; Skovdal, Morten

2017-01-01

This paper draws on interview data to examine how international health care workers navigated risk during the unprecedented Ebola outbreak in West Africa. It identifies the importance of place in risk perception, including how different spatial localities give rise to different feelings of threat...... or safety, some from the construction of physical boundaries, and others mediated through aspects of social relations, such as trust, communication and team dynamics. Referring to these spatial localities as ‘riskscapes’, the paper calls for greater recognition of the role of place in understanding risk...... perception, and how people navigate risk....

Late Proximal Pedicle Hook Migration Into Spinal Canal After Posterior Correction Surgery of Scoliosis Causing Neurologic Deficit: "Proximal Junctional Scoliosis"? Case Series and a Review of the Literature

NARCIS (Netherlands)

Vereijken, I.M.P.; de Kleuver, M.

2013-01-01

Study Design: Case series. Objectives: We describe 4 patients with proximal pedicle hook migration as a late complication (greater than 12 months postoperatively) of posterior correction surgery in adolescent idiopathic scoliosis. We studied failure mechanisms and propose strategies for revision

Implications of Wind-Assisted Aerial Navigation for Titan Mission Planning and Science Exploration

Science.gov (United States)

Elfes, A.; Reh, K.; Beauchamp, P.; Fathpour, N.; Blackmore, L.; Newman, C.; Kuwata, Y.; Wolf, M.; Assad, C.

2010-01-01

The recent Titan Saturn System Mission (TSSM) proposal incorporates a montgolfiere (hot air balloon) as part of its architecture. Standard montgolfiere balloons generate lift through heating of the atmospheric gases inside the envelope, and use a vent valve for altitude control. A Titan aerobot (robotic aerial vehicle) would have to use radioisotope thermoelectric generators (RTGs) for electric power, and the excess heat generated can be used to provide thermal lift for a montgolfiere. A hybrid montgolfiere design could have propellers mounted on the gondola to generate horizontal thrust; in spite of the unfavorable aerodynamic drag caused by the shape of the balloon, a limited amount of lateral controllability could be achieved. In planning an aerial mission at Titan, it is extremely important to assess how the moon-wide wind field can be used to extend the navigation capabilities of an aerobot and thereby enhance the scientific return of the mission. In this paper we explore what guidance, navigation and control capabilities can be achieved by a vehicle that uses the Titan wind field. The control planning approach is based on passive wind field riding. The aerobot would use vertical control to select wind layers that would lead it towards a predefined science target, adding horizontal propulsion if available. The work presented in this paper is based on aerodynamic models that characterize balloon performance at Titan, and on TitanWRF (Weather Research and Forecasting), a model that incorporates heat convection, circulation, radiation, Titan haze properties, Saturn's tidal forcing, and other planetary phenomena. Our results show that a simple unpropelled montgolfiere without horizontal actuation will be able to reach a broad array of science targets within the constraints of the wind field. The study also indicates that even a small amount of horizontal thrust allows the balloon to reach any area of interest on Titan, and to do so in a fraction of the time needed

SMART STICK DESIGN WITH OBSTACLE DETECTION AND NAVIGATION AS THE HELPING TOOL FOR BLIND PEOPLE

OpenAIRE

Sumar Hadi*, Susilo Adi Widyanto, Paryanto, Kurnia Chamid, Rachmat Muhamad Andika

2018-01-01

Smart stick designed for the blind people, this appliance can help detect obstacles with the use of infrared sensor, ultrasonic and water. The obstacles in a distance of about 3 m can be detected assistance from this sensor. In addition, we use GPS (Global Positioning System) to give the position and navigation on the stick. Using GPS (Global Positioning System) help the blind people reaches its destination. GPS (Global Positioning System) recipients to get the location of the latest and the ...

Magnetic navigation in a coronary phantom: experimental results.

Science.gov (United States)

García-García, Héctor M; Tsuchida, Keiichi; Meulenbrug, Hans; Ong, Andrew T L; Van der Giessen, Willem J; Serruys, Patrick W

2005-11-01

The objective was to investigate the efficacy of a magnetic navigation system (MNS) in a coronary phantom. The number of coronary interventional procedures performed is steadily increasing with the availability of new devices to treat more complex lesions. Vessel tortuosity remains an important limiting factor in percutaneous coronary intervention. The MNS can orient the tip of magnetized wire. The coronary phantom is a representation of the coronary tree. Two operators using both a magnetic wire and a standard wire, measured the procedural time (PT), the fluoroscopic time (FT) and the radiation exposure/area product (DAP) required to navigate through to fourteen segments. Ten wire advancements were performed per segment. In all but two segments, the PT was significantly longer using magnetic navigation than using manual navigation. The median FT in the left main artery (LMA) - first septal segment was 7 seconds vs. 18 seconds, with magnetic and manual navigation respectively, (p=0.05); in the LMA - obtuse marginal segment the median FT was 15 seconds with magnetic navigation vs. 29.5 seconds with manual navigation, (p=0.01); in the segment from proximal right coronary artery (RCA1) to the acute marginal branch, the median FT was 8 seconds with magnetic vs. 11 seconds with manual navigation, (p=0.05); and in the RCA1 -posterior descending segment the median FT was 9.5 seconds with magnetic vs. 15 seconds with manual navigation, (p=0.006). The MNS facilitates wire access to distal segments in a coronary phantom, with a reduction in FT and radiation exposure using magnetic navigation in tortuous segments.

Integrated INS/GPS Navigation from a Popular Perspective

Science.gov (United States)

Omerbashich, Mensur

2002-01-01

Inertial navigation, blended with other navigation aids, Global Positioning System (GPS) in particular, has gained significance due to enhanced navigation and inertial reference performance and dissimilarity for fault tolerance and anti-jamming. Relatively new concepts based upon using Differential GPS (DGPS) blended with Inertial (and visual) Navigation Sensors (INS) offer the possibility of low cost, autonomous aircraft landing. The FAA has decided to implement the system in a sophisticated form as a new standard navigation tool during this decade. There have been a number of new inertial sensor concepts in the recent past that emphasize increased accuracy of INS/GPS versus INS and reliability of navigation, as well as lower size and weight, and higher power, fault tolerance, and long life. The principles of GPS are not discussed; rather the attention is directed towards general concepts and comparative advantages. A short introduction to the problems faced in kinematics is presented. The intention is to relate the basic principles of kinematics to probably the most used navigation method in the future-INS/GPS. An example of the airborne INS is presented, with emphasis on how it works. The discussion of the error types and sources in navigation, and of the role of filters in optimal estimation of the errors then follows. The main question this paper is trying to answer is 'What are the benefits of the integration of INS and GPS and how is this, navigation concept of the future achieved in reality?' The main goal is to communicate the idea about what stands behind a modern navigation method.

Development of a multimode navigation system for an assistive robotics project

OpenAIRE

Cherubini , Andrea; Oriolo , G; Macri , F; Aloise , F; Babiloni , F; Cincotti , F; Mattia , D

2007-01-01

International audience; Assistive technology is an emerging area where robotic devices can be used to strengthen the residual abilities of individuals with motor disabilities or to help them achieve independence in the activities of daily living. This paper deals with a project aimed at designing a system that provides remote control of home-installed appliances, including the Sony AIBO, a commercial mobile robot. The development of the project is described by focusing on the design of the ro...

Piles, tabs and overlaps in navigation among documents

DEFF Research Database (Denmark)

Jakobsen, Mikkel Rønne; Hornbæk, Kasper

2010-01-01

Navigation among documents is a frequent, but ill supported activity. Overlapping or tabbed documents are widespread, but they offer limited visibility of their content. We explore variations on navigation support: arranging documents with tabs, as overlapping windows, and in piles. In an experim......Navigation among documents is a frequent, but ill supported activity. Overlapping or tabbed documents are widespread, but they offer limited visibility of their content. We explore variations on navigation support: arranging documents with tabs, as overlapping windows, and in piles....... In an experiment we compared 11 participants’ navigation with these variations and found strong task effects. Overall, overlapping windows were preferred and their structured layout worked well with some tasks. Surprisingly, tabbed documents were efficient in tasks requiring simply finding a document. Piled...... on document navigation and its support by piling....

An Integrated Approach to Electronic Navigation

National Research Council Canada - National Science Library

Shaw, Peter; Pettus, Bill

2001-01-01

While the Global Positioning System (GPS) is and will continue to be an excellent navigation system, it is neither flawless nor is it the only system employed in the navigation of today's seagoing warfighters...

Fault-tolerant Sensor Fusion for Marine Navigation

DEFF Research Database (Denmark)

Blanke, Mogens

2006-01-01

Reliability of navigation data are critical for steering and manoeuvring control, and in particular so at high speed or in critical phases of a mission. Should faults occur, faulty instruments need be autonomously isolated and faulty information discarded. This paper designs a navigation solution...... where essential navigation information is provided even with multiple faults in instrumentation. The paper proposes a provable correct implementation through auto-generated state-event logics in a supervisory part of the algorithms. Test results from naval vessels document the performance and shows...... events where the fault-tolerant sensor fusion provided uninterrupted navigation data despite temporal instrument defects...

Pedicled Instep Flap and Tibial Nerve Reconstruction in a Cynomolgus Monkey [Macaca fascicularis

Directory of Open Access Journals (Sweden)

Ruth Weiss

2016-01-01

Full Text Available A male cynomolgus monkey experienced extensive soft tissue trauma to the right caudal calf area. Some weeks after complete healing of the original wounds, the monkey developed a chronic pressure sore on plantar surface of the heel of its right foot. A loss of sensitivity in the sole of the foot was hypothesized. The skin defect was closed by a medial sensate pedicled instep flap followed by counter transplantation of a full thickness graft from the interdigital webspace. The integrity of the tibial nerve was revised and reconstructed by means of the turnover flap technique. Both procedures were successful. This is an uncommon case in an exotic veterinary patient as it demonstrates a reconstructive skin flap procedure for the treatment of a chronic, denervated wound in combination with the successful reconstruction of 2.5 cm gap in the tibial nerve.

Black Women Resident Assistants: Seeking and Serving as Bridges, Mentors, Advisors, Filters, and Community Builders

Science.gov (United States)

Roland, Ericka; Agosto, Vonzell

2017-01-01

This article reports on a phenomenographic study of Black women undergraduates who were resident assistants in a predominantly White institution (PWI) of higher education. Critical race feminism, namely intersectionality, was used to explore how they navigated the responsibilities of their position and social identities. Findings are that…

Navigation in Cross-cultural business relationships

DEFF Research Database (Denmark)

Andersen, Poul Houman

2001-01-01

Cross-cultural business navigation concerns the process of handling the complexity of several interacting cultural spheres of influence......Cross-cultural business navigation concerns the process of handling the complexity of several interacting cultural spheres of influence...

Registration of 2D C-Arm and 3D CT Images for a C-Arm Image-Assisted Navigation System for Spinal Surgery

Directory of Open Access Journals (Sweden)

Chih-Ju Chang

2015-01-01

Full Text Available C-Arm image-assisted surgical navigation system has been broadly applied to spinal surgery. However, accurate path planning on the C-Arm AP-view image is difficult. This research studies 2D-3D image registration methods to obtain the optimum transformation matrix between C-Arm and CT image frames. Through the transformation matrix, the surgical path planned on preoperative CT images can be transformed and displayed on the C-Arm images for surgical guidance. The positions of surgical instruments will also be displayed on both CT and C-Arm in the real time. Five similarity measure methods of 2D-3D image registration including Normalized Cross-Correlation, Gradient Correlation, Pattern Intensity, Gradient Difference Correlation, and Mutual Information combined with three optimization methods including Powell’s method, Downhill simplex algorithm, and genetic algorithm are applied to evaluate their performance in converge range, efficiency, and accuracy. Experimental results show that the combination of Normalized Cross-Correlation measure method with Downhill simplex algorithm obtains maximum correlation and similarity in C-Arm and Digital Reconstructed Radiograph (DRR images. Spine saw bones are used in the experiment to evaluate 2D-3D image registration accuracy. The average error in displacement is 0.22 mm. The success rate is approximately 90% and average registration time takes 16 seconds.

Can computer assistance improve the clinical and functional scores in total knee arthroplasty?

Science.gov (United States)

Hernández-Vaquero, Daniel; Suarez-Vazquez, Abelardo; Iglesias-Fernandez, Susana

2011-12-01

Surgical navigation in TKA facilitates better alignment; however, it is unclear whether improved alignment alters clinical evolution and midterm and long-term complication rates. We determined the alignment differences between patients with standard, manual, jig-based TKAs and patients with navigation-based TKAs, and whether any differences would modify function, implant survival, and/or complications. We retrospectively reviewed 97 patients (100 TKAs) undergoing TKAs for minimal preoperative deformities. Fifty TKAs were performed with an image-free surgical navigation system and the other 50 with a standard technique. We compared femoral angle (FA), tibial angle (TA), and femorotibial angle (FTA) and determined whether any differences altered clinical or functional scores, as measured by the Knee Society Score (KSS), or complications. Seventy-three patients (75 TKAs) had a minimum followup of 8 years (mean, 8.3 years; range, 8-9.1 years). All patients included in the surgical navigation group had a FTA between 177° and 182º. We found no differences in the KSS or implant survival between the two groups and no differences in complication rates, although more complications occurred in the standard technique group (seven compared with two in the surgical navigation group). In the midterm, we found no difference in functional and clinical scores or implant survival between TKAs performed with and without the assistance of a navigation system. Level II, therapeutic study. See the Guidelines online for a complete description of levels of evidence.

Comparative advantage between traditional and smart navigation systems

Science.gov (United States)

Shin, Jeongkyu; Kim, Pan-Jun; Kim, Seunghwan

2013-03-01

The smart navigation system that refers to real-time traffic data is believed to be superior to traditional navigation systems. To verify this belief, we created an agent-based traffic model and examined the effect of changing market share of the traditional shortest-travel-time algorithm based navigation and the smart navigation system. We tested our model on the grid and actual metropolitan road network structures. The result reveals that the traditional navigation system have better performance than the smart one as the market share of the smart navigation system exceeds a critical value, which is contrary to conventional expectation. We suggest that the superiority inversion between agent groups is strongly related to the traffic weight function form, and is general. We also found that the relationship of market share, traffic flow density and travel time is determined by the combination of congestion avoidance behavior of the smartly navigated agents and the inefficiency of shortest-travel-time based navigated agents. Our results can be interpreted with the minority game and extended to the diverse topics of opinion dynamics. This work was supported by the Original Technology Research Program for Brain Science through the National Research Foundation of Korea funded by the Ministry of Education, Science and Technology(No. 2010-0018847).

A fuzzy logic based navigation for mobile robot