Mechanical failure of spine posterior fixation in the lumbar region Is suspected to occur more frequently when the
Study Design: Retrospective chart review. Summary of Background Data: Spinal osteotomy in ankylosing spondylitis is performed to restore forward gaze and
Objectives. The objective of this study was to assess the association between whole body
Introduction: Total lumbar disc replacement (TLDR) is a motion-preserving alternative to lumbar spinal fusion for degenerative disc disease. Although in vitro cadaveric studies have provided invaluable information in preserving motion and possibly prevent abnormal loading at the adjacent level for TLDR, there is still lack evidence of in vivo consequences for
Objective. To determine if there is a differing effect between two spinal implant systems on
This study is a retrospective monocentric analysis of changes in spinopelvic sagittal alignment after in situ fusion of L5-S1 spondylolisthesis. In situ fusion is a safety procedure with good functionnal outcome, but the consequences on the spinopelvic
Introduction
Purpose: Single-segment wedge osteotomy is classically proposed to correct for kyphosis subsequent to ankylosing spondylitits. We analysed the usefulness of this technique for other indications (revision procedures for flat back and deformed calluses of the lumbar spine) by studying the overall
Introduction: Surgical treatment is indicated in Scheuermann’s disease with severe kyphotic deformity, and/or unremitting pain. Proximal or distal junctional kyphosis and loss of correction have been reported in the literature, due to short fusion level, overcorrection, or posterior only surgery with failure to release anterior tethering. We reviewed surgically treated Scheuermann’s kyphosis cases, to evaluate the factors affecting the
Purpose. compare the radiological results in
Background Context: Total disc replacement (TDR) gained enormous popularity as a treatment option for symptomatic degenerative disc disease in the last few years. But the impact of the prosthesis design on the segmental biomechanics in most instances still remains unclear. As TDR results in a distraction of the capsuloligamentous structures, the disc height seems to be of crucial importance for the further biomechanical function of the operated level. Yet the biomechanical role of disc height after TDR still remains unclear. Purpose: The purpose of study was to evaluate the influence of prosthesis height after total disc replacement on: 1) the
High-grade dysplastic spondylolisthesis is a disabling disorder for which many different operative techniques have been described. The aim of this study is to evaluate Scoliosis Research Society 22-item (SRS-22r) scores, global balance, and regional spino-pelvic alignment from two to 25 years after surgery for high-grade dysplastic spondylolisthesis using an all-posterior partial reduction, transfixation technique. SRS-22r and full-spine lateral radiographs were collected for the 28 young patients (age 13.4 years (SD 2.6) who underwent surgery for high-grade dysplastic spondylolisthesis in our centre (Scottish National Spinal Deformity Service) between 1995 and 2018. The mean follow-up was nine years (2 to 25), and one patient was lost to follow-up. The standard surgical technique was an all-posterior, partial reduction, and S1 to L5 transfixation screw technique without direct decompression. Parameters for segmental (slip percentage, Dubousset’s lumbosacral angle) and regional alignment (pelvic tilt, sacral slope, L5 incidence, lumbar lordosis, and thoracic kyphosis) and global balance (T1 spino-pelvic inclination) were measured. SRS-22r scores were compared between patients with a balanced and unbalanced pelvis at final follow-up.Aims
Methods
Ongoing debate exists as to the integrity of the abdominal musculature unit in maintaining spinal support and stability. It is thought that the intra-abdominal pressure generated is important in spine stabilisation. Congenital aplasia of the abdominal musculature, i.e. prune belly syndrome (PBS), might therefore result in loss of spinal function and stability. We discuss the possible role of an intact abdominal musculature mechanism in maintaining spinal saggital balance and its relevance to low back pain with this case illustration of PBS. We also review the literature for the incidence of spinal deformities related to PBS. We present a unique case of a 33-year-old male with PBS that resulted in loss of spinal saggital balance and development of a thoracic hypokyphotic deformity and thoracolumbar scoliosis. The patient also suffered from mild low back pain. Literature review suggests that secondary scoliosis appears to be the most commonly reported spinal deformity with up to 36% of cases being affected in one study. Unequal compressive forces on the vertebral end-plates as a result of changes in static rib support, dynamic paraspinal muscle support, and changes in intrathoracic and intra-abdominal pressures may be the proposed mechanisms for the spinal deformities. Compensatory lumbar paraspinal over-activity due to the inability to generate normal intra-abdominal pressures because of a deficient abdominal wall musculature mechanism seems to be the plausible explanation for the thoracic hypokyphotic deformity observed. As a corollary, a failing abdominal wall musculature mechanism has been implicated in the risk for low back pain and its sequelae. Our case implicates that an intact abdominal musculature unit might be important in the maintenance of overall spinal function and stability. Maintaining normal intra-abdominal pressures, and the effects of abdominal exercises on this mechanism, i.e. training specificity, remain an important adjunct to our routine treatment of patients with low back pain.
Purpose: Analysis of the
Introduction. Flexion instability of the knee accounts for, up to, 22% of reported revisions following TKA. It can present in the early post-operative phase or present— secondary to a rupture of the PCL— in the late post-operative phase. While most reports of instability occur in conjunction with cruciate retaining implants, instability in a posterior-stabilized knee is not uncommon. Due to the prevalence of revision due to instability, the purpose of constructing the following techniques is to utilize intraoperative sensors to quantify flexion gap stability. Methods. 500 posterior cruciate-retaining TKAs were performed between September 2012 and April 2013, by four collaborating surgeons. All surgeons used the same implant system, compatible with a microelectronic tibial insert with which to receive real-time feedback of femoral contact points and joint kinetics. Intraoperative kinematic data, as reported on-screen by the VERASENSE™ knee application, displayed similar loading patterns consistent with identifiable sagittal plane abnormalities. These abnormalities were classified as: “Balanced Flexion Gap,” “Flexion Instability” and “Tight Flexion Gap.” All abnormalities were addressed with the techniques described herein. Results. Balanced Flexion Gap. Flexion balance was achieved when femoral contact points were within the mid-posterior third (Figure 1) of the tibial insert, symmetrical rollback was seen through ROM, intercompartmental loads were balanced, and central contact points displayed less than 10 mm of excursion across the bearing surface during a posterior drawer test. Flexion Instability. The femoral contact point tracking option dynamically displayed the relative motion of distal femur to the proximal tibia during the posterior drawer test, and through range of motion. Excessive excursion of the femoral contact points across the bearing surface, and femoral contact points translating through the anterior third of the tibial trial, was an indication of laxity in the PCL. Surgical correction requires use of a thicker tibial insert, anterior-constrained insert, or a posterior-stabilized knee design (Figure 2). Tight Flexion Gap. Excessive tension in the PCL was displayed during surgery via femoral contact points and excessive high pressures in the posterior compartment during flexion. When a posterior drawer test was applied no excursion of the femoral tibia contact point was seen. Excessively high loading in the posteromedial compartment was corrected through recession of the PCL using an 19 gauge needle or 11 blade. Additional tibial slope was added when excessive loads were seen in both compartments (Figure 3). Discussion. Flexion gap instability, or excessive PCL tension, is a common error resulting in poor patient outcomes and early revision surgery. The techniques described, utilized intraoperative sensor data to address sagittal plane abnormalities in a quantified manner. By using technology to guide the surgeon through appropriate sagittal plane correction, the subtleties in soft-tissue imbalance or suboptimal bone cuts can be accounted for, which otherwise may be overlooked by traditional methods of subjective surgeon “feel.” Longer clinical follow-up of these patients will be necessary to track the outcomes associated with quantifiable
Sagittal alignment of the lumbosacral spine, and specifically pelvic incidence (PI), has been implicated in the development of spine pathology, but generally ignored with regards to diseases of the hip. We aimed to determine if increased PI is correlated with higher rates of hip osteoarthritis (HOA). The effect of PI on the development of knee osteoarthritis (KOA) was used as a negative control. We studied 400 well-preserved cadaveric skeletons ranging from 50 to 79 years of age at death. Each specimen’s OA of the hip and knee were graded using a previously described method. PI was measured from standardised lateral photographs of reconstructed pelvises. Multiple regression analysis was performed to determine the relationship between age and PI with HOA and KOA.Objectives
Methods
Aims. The effect of pelvic tilt (PT) and
To determine if the use of high density implants (i.e. high proportion of pedicle screws relative to number of spinal levels involved) causes significant loss of thoracic kyphosis and its effect on