To investigate and compare the biomechanical characteristics of Bipedicular versus Unipedicular Vertebroplasty in cadaveric
The lumbar spine consists of a mobile segment of 5 vertebrae, which are located between the relatively immobile segments of the thoracic and sacral segments. The bodies are wider and have shorter and heavier pedicles, and the transverse processes project somewhat more laterally and ventrally than other spinal segments. The laminae are shorter vertically than are the bodies and are bridged by strong ligaments. The spinous processes are broader and stronger than are those in the thoracic and cervical spine. Internal fixation as an adjunct to spinal fusion has become increasingly popular in recent years. Stainless steel or titanium plates or rods are longitudinally anchored to the spine by hooks or pedicle screws. Powerful forces can be applied to the spine through these implants to correct deformity. Implants provide immediate rigid spinal immobilization, which allows for early patient mobilization, and provides a more optimal environment for bone graft incorporation. Numerous clinical and experimental studies demonstrate higher fusion rates in patients with rigid internal fixation than in controls without instrumentation. Although various implants are available, pedicle fixation systems are the most commonly used implant type in the lumbosacral spine. The large size of the lumbar pedicles minimizes the number of instrumented motion segments required to achieve adequate stabilization. Many authors have reported loss of postoperative deformity correction after transpedicular screw fixation, ranging from 2.5 degrees to 7.1 degrees. The general preference is to stabilize the fractured
Purpose: The purpose of this work was to study the reliability and the precision of a lumber
Percutaneous vertebroplasty (PVP) is an emerging interventional technique for treatment of vertebral compression fractures. Bone cement is introduced to mechanically augment fracture and pain relief is almost immediate. Recent clinical and biomechanical studies have outlined the phenomenon of fractures occurring in adjacent vertebrae following PVP [. 1. ,. 2. ]. It is widely believed that rigid cement augmentation may cause a shift in the normal loading pattern of the spine thereby resulting in adjacent fractures. However, very few studies have attempted to quantify this effect [. 3. ]. Most biomechanical studies adopt a single vertebral body as a model for PVP analysis. With this approach it is not possible to determine the effect of load distribution on adjacent structures. Where multi-segment vertebrae have been used there is little documentation of the fracture characteristics produced or their repeatability. The purpose of this study was to develop a 3-vertebra model for the biomechanical analysis of PVP. The particular focus was on developing a robust technique for generating repeatable level of fracture severity from specimen to specimen. An alignment device was developed to fit into standard materials testing machine, which allowed constant axial compression without causing lateral bending or flexion-extension of the specimen’s ends. Porcine 3-segment specimens (T8-L2) were mechanically compressed to failure at a rate of 5mm/min applied vertically at a distance of 35% to the anterior edge of the specimen’s anterior-posterior length. During the test load-displacement data was displayed in real time on a PC. In order to generate uniform fractures, a protocol was devised in which the specimens were compressed for a further 6mm after initial yield point. After the initial fracture the segments were augmented with 3ml of PMMA cement injected through each pedicle and then recompressed. The fracture characteristics generated under these conditions were analysed using quantitative microcomputer tomogragy (μCT). μCT images showed that fractures were generated in the central
Considerable numbers of authors have reported the change in periprothetic bone mineral density (BMD) after hip arthroplasty. However, there have been few reports concerning the BMD in the lumbar
Study Design: A retrospective review of the functional outcome of neurologically intact patients with burst fractures of the first lumbar
Purpose: There is scant literature with respect to reproducibility in radiological measurements of vertebral morphology. The purpose was to determine the reliability of measurement of various parameters of vertebral morphology in idiopathic scoliosis. Method: Ten patients with AIS were investigated with standardised low dose multi-slice helical CT. Axial reconstructions in the plane of the T8 (apical)
The aim of this study was to assess the ability of morphological spinal parameters to predict the outcome of bracing in patients with adolescent idiopathic scoliosis (AIS) and to establish a novel supine correction index (SCI) for guiding bracing treatment. Patients with AIS to be treated by bracing were prospectively recruited between December 2016 and 2018, and were followed until brace removal. In all, 207 patients with a mean age at recruitment of 12.8 years (SD 1.2) were enrolled. Cobb angles, supine flexibility, and the rate of in-brace correction were measured and used to predict curve progression at the end of follow-up. The SCI was defined as the ratio between correction rate and flexibility. Receiver operating characteristic (ROC) curve analysis was carried out to assess the optimal thresholds for flexibility, correction rate, and SCI in predicting a higher risk of progression, defined by a change in Cobb angle of ≥ 5° or the need for surgery.Aims
Methods
Objective: To present the clinical features, radiological findings and differential diagnosis of this rare benign condition. Design: Melorheostosis (Leri’s Disease) is a rare mesenchymal dysplasia commonly exhibiting hyperostosis on the internal and external aspect of tubular bones in a sclerodermal distribution. It usually occurs in the limbs, frequently crosses joints and there is often ossification in local soft tissues. Presenting features may include pain, restricted joint movement and skin thickening. It very rarely affects the spine and its cause is unknown. Subject: A 40-year-old female presented with insidious onset of mild mid thoracic back pain. There was no history of trauma and she had no past medical or family history. She underwent a six-month course of physiotherapy but this failed to help her symptoms. She developed a small lump over the area of pain and her GP arranged an X-Ray. This showed an irregular area of high attenuation over the right side of the tenth thoracic
Compressive fracture of osteoporotic vertebrae has been one of the most important health problems in aged societies because severely injured spin might be a reason of bedridden for elderly people. Osteoporosis has been widely assessed by averaged bone mineral density of vertebrae measured using DEXA, however, BMD sometimes does not reflect the strength of vertebrae. CT imaged based finite element method (CT-FEM) has been applied to evaluate the strength of vertebrae based on the biomechanics theory and approved by a part of the highly advanced medical treatment in Japan. In the present study, compressive strength of more than 100 vertebrae were evaluated using CT-FEM, and the correlation between BMD and the strength was thoroughly investigated. It was found that some vertebrae with high BMD could have low strength which may cause fracture easily. Thus, a controversial point of the BMD based diagnosis of osteoporosis was clearly indicated. In this invited talk, some basic theories of CT-FEM and fracture assessment and some key results from the recent study will be presented.
To evaluate the safety and efficacy of vertebroplasty with short segmented cement augmented pedicle screws fixation for severe osteoporotic vertebral compression fractures (OVCF) with posterior/anterior wall fractured patients. A retrospective study of 24 patients of DGOU type-4 (vertebra plana) OVCF with posterior/anterior wall fracture, were treated by vertebroplasty and short segment PMMA cement augmented pedicle screws fixation. Radiological parameters (kyphosis angle and compression ratio) and clinical parameters Visual analogue scale (VAS) and Oswestry disability index (ODI) were analysed.Abstract
Objectives
Methods
A 22-year-old man was admitted to hospital after being assaulted. He complained of a painful neck and upper limbs, with weakness and numbness of his upper limbs. Initial treatment was skull traction for six weeks, during which the motor power in the upper limbs recovered. CT scan of the cervical spine showed a lytic expanding bone lesion in the atlas. At 10 weeks he was transferred to a Spinal Centre, walking normally, with good bladder and bowel control. He was complaining of intermittent occipital headaches and pain at the cervicothoracic junction. He was wearing a cervical orthosis. His neck movements were guarded and markedly restricted. No neurological deficit was detected. A right-sided brachiocephalic artery angiogram showed no abnormality. MR scan showed definite narrowing of the spinal canal at the C2 vertebral level and stress studies some vertebral instability at the atlanto-axial level. Under general anaesthetic a transoral biopsy, curettage, and bone grafting of the atlas was carried out. The biopsy material comprised white membranous-type material, which had the histological features of hydatid cysts. A posterior spinal fusion with instrumentation was performed over posterior vertebral arches Cl to C3. Postoperatively ultrasound of the abdomen and radiograph of the chest did not reveal any further evidence of hydatid disease. Treatment with albendazole was commenced. The diagnosis was not anticipated preoperatively.
To reduce vertebral fractures, emerging techniques such as vertebroplasty need to be improved by studying cement infiltration and leakage within bone. Thus we investigated samples extracted from lumbar spines using μCT to evaluate morphological parameters (trabecular thickness and separation, structural index). The specific finding is that relevant shifts of the trabecular thickness and separation Gaussian medians associated to sharpened distributions are related to donors’ age. These morphological parameters, correlated to common fluid laws, enable the prediction of bone cement flow within vertebrae and provide new ways for designing biomaterials and estimate key vertebroplasty parameters regarding time, pressure and injection site. Osteoporosis, a pathological bone decay leading to fractures, is an economical burden on society. A prevalent fracture site is the spine. To avoid vertebral fractures, emerging techniques such as vertebroplasty are used. Nevertheless, the lack of knowledge relating to cement infiltration, distribution and leakage within vertebrae during cement injection interferes with an appropriate medical practice. This study, by assessing morphological parameters, aims at a better understanding of these processes. The investigation includes size-controlled cylindrical samples (diameter of 18mm and height of 18mm), extracted from five lumbar spines (L1 to L5) of four female donors aged from forty-nine to eighty years old, analysed using micro-Computed Tomography technique (with a voxel size of 18μm*18μm*36μm) and three-dimensional computed reconstructions. Then morphological parameters such as porosity, trabecular thickness, trabecular separation, tissue surface and structural index were extracted from the reconstructed volume using dedicated software. The general findings are significant decreases in bone mass and mineral density while porosity increased and bone anisotropy remains unchanged. The specific finding is that relevant shifts of the trabecular thickness and separation Gaussian medians associated to sharpened distributions are related to donors’ age Previously determined morphological parameters correlated to common fluid laws (Stokes, Reynolds) enable the prediction of bone cement flow, infiltration and leakage during vertebroplasty and thus provide new ways for designing and evaluating biomaterials and estimating key vertebroplasty parameters regarding time, pressure and injection site. Please contact author for diagrams and graphs.
In the previous study regarding the relationship among maximum hip flexion, the pelvis, and the lumbar vertebrae on the sagittal plane, we have found in X-rays that the lumbo lordotic angle (LLA) and the sacral slope angle (SSA) have a large impact on hip flexion angle. We examined hip flexion angles to the various height of the objects (half round plastic tube) placed under the subject's lower back and compared the passive hip flexion angles in the supine position between younger and middle age groups. The participants were 14 healthy volunteers: 7 females with an average age of 17 years (Group 1: G-1), 7 females with an average age of 45 years (Group 2: G-2). The average BMI (Body Mass Index) of volunteers was less than 25, and their Tomas Tests were negative.Introduction
Participants
Variations in pelvic anatomy are a major risk factor for misplaced percutaneous sacroiliac screws used to treat unstable posterior pelvic ring injuries. A better understanding of pelvic morphology improves preoperative planning and therefore minimises the risk of malpositioned screws, neurological or vascular injuries, failed fixation or malreduction. Hence a classification system which identifies the clinically important anatomical variations of the sacrum would improve communication among pelvic surgeons and inform treatment strategy. 300 Pelvic CT scans from skeletally mature trauma patients that did not have pre-existing posterior pelvic pathology were identified. Axial and coronal transosseous corridor widths at both S1 and S2 were recorded. Additionally, the S1 lateral mass angle were also calculated. Pelvises were classified based upon the sacroiliac joint (SIJ) height using the midpoint of the anterior cortex of L5 as a reference point. Four distinct types could be identified:. Type-A – SIJ height is above the midpoint of the anterior cortex of the L5
Aims. The aim of this study was to review the current evidence surrounding curve type and morphology on curve progression risk in adolescent idiopathic scoliosis (AIS). Methods. A comprehensive search was conducted by two independent reviewers on PubMed, Embase, Medline, and Web of Science to obtain all published information on morphological predictors of AIS progression. Search items included ‘adolescent idiopathic scoliosis’, ‘progression’, and ‘imaging’. The inclusion and exclusion criteria were carefully defined. Risk of bias of studies was assessed with the Quality in Prognostic Studies tool, and level of evidence for each predictor was rated with the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach. In all, 6,286 publications were identified with 3,598 being subjected to secondary scrutiny. Ultimately, 26 publications (25 datasets) were included in this review. Results. For unbraced patients, high and moderate evidence was found for Cobb angle and curve type as predictors, respectively. Initial Cobb angle > 25° and thoracic curves were predictive of curve progression. For braced patients, flexibility < 28% and limited in-brace correction were factors predictive of progression with high and moderate evidence, respectively. Thoracic curves, high apical vertebral rotation, large rib
7% of adolescent idiopathic scoliosis (AIS) patients also present with a pars defect. To date, there are no available data on the results of fusion ending proximal to a spondylolysis in the setting of AIS. The aim of this study was to analyze the outcomes of posterior spinal fusion (PSF) in this patient cohort, to investigate if maintaining the lytic segment unfused represents a safe option. Retrospective review of all patients who received PSF for AIS, presented with a spondylolysis or spondylolisthesis and had a min. 2-years follow-up. Demographic data, instrumented levels and preoperative radiographic data were collected. Mechanical complications, coronal or sagittal parameters, amount of slippage and pain levels were evaluated. Data from 22 patients were available (age 14.4 ± 2.5 years), 18 Lenke 1–2 and four Lenke 3–6. Five patients (24%) had an isthmic spondylolisthesis, all Meyerding I. The mean preoperative Cobb angle of the instrumented curves was 58 ± 13°. For 18 patients the lowest instrumented
Background. Surgical site infection following spine surgery is associated with increased morbidity, mortality and increased cost for the health care system. The reported pooled incidence is 3%. Perioperative antibiotic prophylaxis is a key factor in lowering the risk of acquiring an infection. Previous studies have assessed perioperative cefuroxime concentrations in the anterior column of the cervical spine with an anterior surgical approach. However, the majority of surgeries are performed in the posterior column and often involve the lumbar spine. Accordingly, the objective was to compare the perioperative tissue concentrations of cefuroxime in the anterior and posterior column of the same lumbar
Intra-Discal Vacuum Phenomenon (IDVP) represents an intradiscal nitrogen gas accumulation where a cavity opens in a supine position, lowering intra-discal pressure and generating a bubble. IDVP has been observed in up to 20% of elderly patients and reported in almost 50% of chronic LBP patients. With a highly accurate detection on CT, its significance lacks clarity and consideration within normative data. IDVP occurs with patterns of lumbar and/or lumbopelvic morphology and associated diagnoses. Over-60s population based sample of 2020 unrelated CT abdomen scans without acute spinal presentations, with sagittal reconstructions, inclusive of T12 to femoral heads, were analyzed for IDVP and pelvic incidence (PI). Subjects with diagnostic morphological associations of the lumbar spine, including previous fracture, autofusion, transitional
Dysmorphic pelves are a known risk factor for malpositioned iliosacral screws. Improved understanding of pelvic morphology will minimise the risk of screw misplacement, neurovascular injuries and failed fixation. Existing classifications for sacral anatomy are complex and impractical for clinical use. We propose a CT-based classification using variations in pelvic anatomy to predict the availability of transosseous corridors across the sacrum. The classification aims to refine surgical planning which may reduce the risk of surgical complications. The authors postulated 4 types of pelves. The “superior most point of the sacroiliac joint” (sSIJ) typically corresponds with the mid-lower half of the L5 vertebral body. Hence, “the anterior cortex of L5” (L5. a. ) was divided to reference 3 distinct pelvic groups. A 4. th. group is required to represent pelves with a lumbosacral transitional