Non-traumatic complete cervical spine dislocation with severe fixed kyphosis: successful multidisciplinary approach to a challenging case.

Background: To our knowledge, there is no previous report in the literature of non-traumatic neglected complete cervical spine dislocation characterized by anterior spondyloptosis of C4, extreme head drop, and irreducible cervicothoracic kyphosis.

Case Presentation: We report the case of a 33-year-old Caucasian man with a 17-year history of severe immune polymyositis and regular physiotherapy who presented with severe non-reducible kyphosis of the cervicothoracic junction and progressive tetraparesia for several weeks after a physiotherapy session. Radiographs, computed tomography, and magnetic resonance imaging revealed a complete dislocation at the C4-C5 level, with C4 spondyloptosis, kyphotic angulation, spinal cord compression, and severe myelopathy.

Total en bloc spondylectomy of T11 and spine shortening performed on a 17-month-old patient: art of the possible.

Study Design: Case report.

Purpose: The authors used spine shortening as an alternative strategy to intercalary graft fixation to restore permanent spine stability for a 17-month-old infant who received total en bloc spondylectomy (TES) of T11 to treat an embryonic rhabdomyosarcoma. TES involves complete removal of vertebra, compensated by spine reconstruction using intercalary allografts and permanent posterior instrumentation, which is not possible for skeletally immature patients with high growth potential and non-ossified vertebrae.

Clinical and demographic profile of admitted victims in a tertiary hospital after the 2015 earthquake in Nepal.

Background: In 2015, an earthquake killing 9,000 and injuring 22,000 people hit Nepal. The Tribhuvan University Teaching Hospital (TUTH), a reference tertiary hospital, was operational immediately after the earthquake. We studied the profile of earthquake victims admitted in TUTH and assessed what factors could influence hospital length of stay.

Gait in patients with adolescent idiopathic scoliosis. Effect of surgery at 10 years of follow-up.

Purpose: To assess radiological and gait biomechanical changes before, at one and 10 years after surgery in AIS patients.

Methods: This clinical prospective study included fifteen adult women (mean[SD] age: 26 [1] years) diagnosed with thoraco-lumbar/lumbar AIS and operated 10 years ago. Clinical, radiological and gait variables, including kinematics, electromyography (EMG), mechanics and energetics were compared between presurgery (S0), 1 year (S1) and 10 years (S2) postsurgery period using a one way repeated measure ANOVA.

Radiation dose reduction in thoracic and lumbar spine instrumentation using navigation based on an intraoperative cone beam CT imaging system: a prospective randomized clinical trial.

Purpose: Spine surgery still remains a challenge for every spine surgeon, aware of the potential serious outcomes of misplaced instrumentation. Though many studies have highlighted that using intraoperative cone beam CT imaging and navigation systems provides higher accuracy than conventional freehand methods for placement of pedicle screws in spine surgery, few studies are concerned about how to reduce radiation exposure for patients with the use of such technology. One of the main focuses of this study is based on the ALARA principle (as low as reasonably achievable).

Pedicle screw insertion accuracy in terms of breach and reposition using a new intraoperative cone beam computed tomography imaging technique and evaluation of the factors associated with these parameters of accuracy: a series of 695 screws.

Purpose: The goals of this study were to assess the accuracy of pedicle screw insertion using an intraoperative cone beam computed tomography (CBCT) system, and to analyze the factors potentially influencing this accuracy.

Methods: Six hundred and ninety-five pedicle screws were inserted in 118 patients between October 2013 and March 2016. Screw insertion was performed using 2D-fluoroscopy or CBCT-based navigation.

Accuracy of a new intraoperative cone beam CT imaging technique (Artis zeego II) compared to postoperative CT scan for assessment of pedicle screws placement and breaches detection.

Purpose: The goal of this study was to compare the accuracy of a novel intraoperative cone beam computed tomography (CBCT) imaging technique with that of conventional computed tomography (CT) scans for assessment of pedicle screw placement and breach detection.

Methods: Three hundred and forty-eight pedicle screws were inserted in 58 patients between October 2013 and March 2016. All patients had an intraoperative CBCT scan and a conventional CT scan to verify the placement of the screws.

Patient Specific Instruments for Complex Tumor Resection-Reconstruction Surgery within the Pelvis: A Series of 4 Cases.

The pelvis bone resection-reconstruction surgery is one of the most challenging fields in orthopedics. Being applied for tumors, as for other complex reconstruction cases, this type of surgery needs careful planning and is time consuming, in order to obtain proper accuracy. Unfortunately not all the time the expected accuracy is met, with consequences for the patients.

CorMatrix valved conduit in a porcine model: long-term remodelling and biomechanical characterization.

Objectives: Porcine small intestinal submucosa extracellular matrix (CorMatrix; CorMatrix Cardiovascular, Rosewell, GA) is a relatively novel tissue substitute used in cardiovascular applications. We investigated the biological reaction and remodelling of CorMatrix as a tri-leaflet valved conduit in a pig model. We hypothesized that CorMatrix maintains a durable architecture as a valved conduit and remodels to resemble surrounding tissues.

MRI-Based Assessment of Safe Margins in Tumor Surgery.

Introduction. In surgical oncology, histological analysis of excised tumor specimen is the conventional method to assess the safety of the resection margins. We tested the feasibility of using MRI to assess the resection margins of freshly explanted tumor specimens in rats.

Effect of long-term orthotic treatment on gait biomechanics in adolescent idiopathic scoliosis.

Background Context: A previous study showed subtle biomechanical changes in the gait of unbraced adolescent idiopathic scoliosis (AIS) patients such as a reduction of pelvic, hip, knee, and ankle displacements. However, lumbopelvic muscles' timing activity was bilaterally increased during gait and correlated to excessive oxygen consumption as compared with healthy subjects. Usually, a brace, when indicated, is worn strictly for 22 hours every day in skeletally immature idiopathic scoliotic girls.

Improved accuracy with 3D planning and patient-specific instruments during simulated pelvic bone tumor surgery.

In orthopaedic surgery, resection of pelvic bone tumors can be inaccurate due to complex geometry, limited visibility and restricted working space of the pelvis. The present study investigated accuracy of patient-specific instrumentation (PSI) for bone-cutting during simulated tumor surgery within the pelvis. A synthetic pelvic bone model was imaged using a CT-scanner.

Very short-term effect of brace wearing on gait in adolescent idiopathic scoliosis girls.

Purpose: Adolescent idiopathic scoliotic (AIS) deformity induces excessive oxygen consumption correlated to a bilateral increase of lumbo-pelvic muscles timing activity (EMG) during gait. Wearing a brace, the usual treatment for AIS, by supporting the spine and the pelvis, would generate lumbo-pelvic muscular relaxation and consequently reduce excessive oxygen consumption. The purpose of this study was to evaluate the short-term effect of bracing on gait biomechanics in scoliotic spine when compared with normal braced spine.

Time spent per patient in lumbar spinal stenosis surgery.

Purpose: To examine the time needed from a surgeon's viewpoint to treat a patient operated for lumbar spinal stenosis. We firstly aimed to give evidence of the wide ranging duration of standardized procedure. Secondly, we investigated factors affecting the time allocated to each patient.

Computer-assisted planning and navigation improves cutting accuracy during simulated bone tumor surgery of the pelvis.

Background: Resection of bone tumors within the pelvis requires good cutting accuracy to achieve satisfactory safe margins. Manually controlled bone cutting can result in serious errors, especially due to the complex three-dimensional geometry, limited visibility, and restricted working space of the pelvic bone. This experimental study investigated cutting accuracy during navigated and non-navigated simulated bone tumor cutting in the pelvis.

A multibody-based approach to the computation of spine intervertebral motions in scoliotic patients.

In idiopathic scoliotic patients, dynamical intervertebral efforts acting between vertebrae seem to be correlated with the spinal deformity. The quantification of these efforts, which is useful for the orthopedic surgeons to set up their surgical planning is the final objective of the present research. As a first step, we focus in this contribution on the geometrical reconstruction of the spine and especially on the rotation sequences between vertebrae in a multibody approach.

Computer-Navigated Bone Cutting in the Resection of a Pelvic Bone Tumor and Reconstruction with a Massive Bone Allograft.

Introduction: We present here a surgical technique using a navigation system and an oscillating saw for the resection of a pelvic bone tumor combined with an allograft reconstruction.

Step 1 Preoperative Planning: The surgeon and radiologist together delineate the tumor on each magnetic resonance imaging (MRI) slice; then the surgeon defines target planes for tumor resection and transfers them to the allograft.

Step 2 Patient Positioning And Surgical Exposure: With the patient in the lateral decubitus position, combine ilioinguinal with iliocrural and obturator surgical approaches to expose the ilium.

Computer-assisted resection and reconstruction of pelvic tumor sarcoma.

Pelvic sarcoma is associated with a relatively poor prognosis, due to the difficulty in obtaining an adequate surgical margin given the complex pelvic anatomy. Magnetic resonance imaging and computerized tomography allow valuable surgical resection planning, but intraoperative localization remains hazardous. Surgical navigation systems could be of great benefit in surgical oncology, especially in difficult tumor location; however, no commercial surgical oncology software is currently available.

Computer-assisted and robot-assisted technologies to improve bone-cutting accuracy when integrated with a freehand process using an oscillating saw.

Background: In orthopaedic surgery, many interventions involve freehand bone cutting with an oscillating saw. Such freehand procedures can produce large cutting errors due to the complex hand-controlled positioning of the surgical tool. This study was performed to investigate the potential improvements in cutting accuracy when computer-assisted and robot-assisted technologies are applied to a freehand bone-cutting process when no jigs are available.

Synergetic effect of freeze-drying and gamma irradiation on the mechanical properties of human cancellous bone.

Freeze-drying and irradiation are common process used by tissue banks to preserve and sterilize bone allografts. Freeze dried irradiated bone is known to be more brittle. Whether bone brittleness is due to irradiation alone, temperature during irradiation or to a synergetic effect of the freeze-drying-irradiation process was not yet assessed.

Selection of massive bone allografts using shape-matching 3-dimensional registration.

Background And Purpose: Massive bone allografts are used when surgery causes large segmental defects. Shape-matching is the primary criterion for selection of an allograft. The current selection method, based on 2-dimensional template comparison, is inefficient for 3-dimensional complex bones.

Ergonomic evaluation of 3D plane positioning using a mouse and a haptic device.

Background: Preoperative planning and intraoperative assistance are needed to improve accuracy in tumour surgery. To be accepted, these processes must be efficient. An experiment was conducted to compare a mouse and a haptic device, with and without force feedback, to perform plan positioning in a 3D space.

Particle size influence in an impaction bone grafting model. Comparison of fresh-frozen and freeze-dried allografts.

Background: Impaction bone grafting with large particles is considered as mechanically superior to smaller morsels. Interest of freeze-dried irradiated bone for impaction bone grafting has been observed with small particles. Influence of bone process on other particle sizes still needed to be assessed.

Measurement of bone cyst fluid volume using k-means clustering.

We designed a semiautomatic segmentation method to easily measure the volume of a bone cyst (simple or aneurysmal) from magnetic resonance imaging (MRI). This method only considers the fluid part of the cyst, even when there are several fluid intensities (fluid-fluid levels) or the cyst is multi-loculated. The nonhomogeneity phenomenon inherent in MRI was handled by a k-means clustering algorithm that classified all of the voxels corresponding to the cyst fluid as the same voxel intensity.

Accuracy in planar cutting of bones: an ISO-based evaluation.

Background: Computer- and robot-assisted technologies are capable of improving the accuracy of planar cutting in orthopaedic surgery. This study is a first step toward formulating and validating a new evaluation methodology for planar bone cutting, based on the standards from the International Organization for Standardization.

Methods: Our experimental test bed consisted of a purely geometrical model of the cutting process around a simulated bone.