Kariman Abelin-Genevois

Functional variants of POC5 identified in patients with idiopathic scoliosis

Idiopathic scoliosis (IS) is a spine deformity that affects approximately 3% of the population. The underlying causes of IS are not well understood, although there is clear evidence that there is a genetic component to the disease. Genetic mapping studies suggest high genetic heterogeneity, but no IS disease-causing gene has yet been identified. Here, genetic linkage analyses combined with exome sequencing identified a rare missense variant (p.A446T) in the centriolar protein gene POC5 that cosegregated with the disease in a large family with multiple members affected with IS. Subsequently, the p.A446T variant was found in an additional set of families with IS and in an additional 3 cases of IS. Moreover, POC5 variant p.A455P was present and linked to IS in one family and another rare POC5 variant (p.A429V) was identified in an additional 5 cases of IS. In a zebrafish model, expression of any of the 3 human IS-associated POC5 variant mRNAs resulted in spine deformity, without affecting other skeletal structures. Together, these findings indicate that mutations in the POC5 gene contribute to the occurrence of IS.

Tridimensional trunk surface acquisition for brace manufacturing in idiopathic scoliosis

AbstractIntroduction Brace manufacturing for idiopathic scoliosis requires trunk surface acquisition. Two methods are currently available to design the trunk shape: craft made technique based on a plaster mold and computer-aided design with 3-D reconstruction of the trunk by optical scanning. The objective of the present review was to compare these two methods.Methodology We describe the different steps to design and manufacture braces used for spinal deformities.ResultsOur prospective evaluation showed good results in terms of the correction achieved and regarding patients’ in-brace comfort.DiscussionOptical scanning for computer-aided design and manufacturing (CAD-CAM) of trunk orthoses have proven their effectiveness. These technologies may help in monitoring conservative treatment and may enhance the brace interaction with the spinal deformity when orthopedic treatment is indicated.

Acl Reconstruction in Children: An Original Technique

Early reconstruction after anterior cruciate ligament (ACL) rupture in children with open physis was found to be a better strategy compared with delayed ACL reconstruction at skeletal maturity. This article focuses on an original technique for ACL reconstruction in children and adolescents. The rationale of the procedure is based on avoiding the danger of a femoral tunnel and fixation systems that may lead to growth arrest. Part of the quadriceps tendon with a trapezoidal patella bone block was harvested after arthroscopic exploration and addressing other intra-articular injuries like meniscal tears. The bone-tendon graft was inserted through a combined intraepiphyseal femoral tunnel drilled from outside-in under fluoroscopic imaging and a long vertical arthroscopically drilled transphyseal tibial tunnel. The bone block was impacted in the femoral tunnel, allowing primary fixation without any associated material. The tibial fixation is obtained with a strictly metaphyseal screw and postfixation with a staple. The advantages of the technique are multiple: anatomic and isometric reconstruction, arthroscopically surgery, strong adaptable long graft with excellent bone to bone press-fit fixation on the femur, and preservation of the femoral physis. Indications, the step-by-step procedure, postoperative care, complications, and results are reported in this paper.

Evolution of adolescent idiopathic scoliosis: Results of a multicenter study at 20 years’ follow-up

INTRODUCTION To date there is no consensus on therapeutic indications in adolescent idiopathic scoliosis (AIS) with curvature between 30° and 60° at the end of growth. OBJECTIVE The objective of this study was to assess outcome in patients with moderate AIS. MATERIAL AND METHODS A multicenter retrospective study was conducted. Inclusion criteria were: Cobb angle, 30-60° at end of growth; and follow-up > 20 years. The data collected were angular values in adolescence and at last follow-up, and quality of life scores at follow-up. RESULTS A total of 258 patients were enrolled: 100 operated on in adolescence, 116 never operated on, and 42 operated on in adulthood. Mean follow-up was 27.8 years. Cobb angle progression significantly differed between the 3 groups: 3.2° versus 8.8° versus 23.6°, respectively; P < 0.001. In lumbar scoliosis, the risk of progression to ≥ 20° was significantly higher for initial Cobb angle > 35° (OR=4.278, P=0.002). There were no significant differences in quality of life scores. DISCUSSION Patients operated on in adolescence showed little radiological progression, demonstrating the efficacy of surgical treatment for curvature greater than 50°. Curvature greater than 40° was progressive and may require surgery in adulthood. Lumbar scoliosis showed greater potential progression than thoracic scoliosis in adulthood, requiring fusion as of 35° angulation. LEVEL OF EVIDENCE IV, retrospective study.

Early Detection of Progressive Adolescent Idiopathic Scoliosis: A Severity Index.

Study Design. Early detection of progressive adolescent idiopathic scoliosis (AIS) was assessed based on 3D quantification of the deformity. Objective. Based on 3D quantitative description of scoliosis curves, the aim is to assess a specific phenotype that could be an early detectable severity index for progressive AIS. Summary of Background Data. Early detection of progressive scoliosis is important for adapted treatment to limit progression. However, progression risk assessment is mainly based on the follow up, waiting for signs of rapid progression that generally occur during the growth peak. Methods. Sixty-five mild scoliosis (16 boys, 49 girls, Cobb Angle between 10 and 20°) with a Risser between 0 and 2 were followed from their first examination until a decision was made by the clinician, either considering the spine as stable at the end of growth (26 patients) or planning to brace because of progression (39 patients). Calibrated biplanar x-rays were performed and 3D reconstructions of the spine allowed calculating six local parameters related to main curve deformity. For progressive curve 3D phenotype assessment, data were compared with those previously assessed for 30 severe scoliosis (Cobb Angle > 35°), 17 scoliosis before brace (Cobb Angle > 29°) and 53 spines of nonscoliosis subjects. A predictive discriminant analysis was performed to assess similarity of mild scoliosis curves either to those of scoliosis or nonscoliosis spines, yielding a severity index (S-index). S-index value at first examination was compared with clinical outcome. Results. At the first exam, 53 out of 65 predictions (82%) were in agreement with actual clinical outcome. Approximately, 89% of the curves that were predicted as progressive proved accurate. Conclusion. Although still requiring large scale validation, results are promising for early detection of progressive curves. Level of Evidence: 2

Mechanical coupling effects into a L3-L5 vertebral segment.

In the surgery of the adolescent idiopathic scoliosis (AIS), it has been shown that arthrodesis was increasing the intervertebral disc volume of discs below spine fusion post-operatively. Another consequence was the variation of hydration of disc remained free. The surgery induced a redistribution of strain energy but it is challenging to identify the mechanical loadings in-vivo. We hypothesized that the direct simulation of a vertebral segment under compression, bending and shear supported the analysis of mechanical transfers in-vivo.