Adolescent Idiopathic Scoliosis Cases Research Articles

Biomechanical effect of pedicle screw distribution in AIS instrumentation using a segmental translation technique: computer modeling and simulation

BackgroundEfforts to select the appropriate number of implants in adolescent idiopathic scoliosis (AIS) instrumentation are hampered by a lack of biomechanical studies. The objective was to biomechanically evaluate screw density at different regions in the curve for AIS correction to test the hypothesis that alternative screw patterns do not compromise anticipated correction in AIS when using a segmental translation technique.MethodsInstrumentation simulations were computationally performed for 10 AIS cases. We simulated simultaneous concave and convex segmental translation for a reference screw pattern (bilateral polyaxial pedicle screws with dorsal height adjustability at every level fused) and four alternative patterns; screws were dropped respectively on convex or concave side at alternate levels or at the periapical levels (21 to 25% fewer screws). Predicted deformity correction and screw forces were compared.ResultsFinal simulated Cobb angle differences with the alternative screw patterns varied between 1° to 5° (39 simulations) and 8° (1 simulation) compared to the reference maximal density screw pattern. Thoracic kyphosis and apical vertebral rotation were within 2° of the reference screw pattern. Screw forces were 76 ± 43 N, 96 ± 58 N, 90 ± 54 N, 82 ± 33 N, and 79 ± 42 N, respectively, for the reference screw pattern and screw dropouts at convex alternate levels, concave alternate levels, convex periapical levels, and concave periapical levels. Bone-screw forces for the alternative patterns were higher than the reference pattern (p < 0.0003). There was no statistical bone-screw force difference between convex and concave alternate dropouts and between convex and concave periapical dropouts (p > 0.28). Alternate dropout screw forces were higher than periapical dropouts (p < 0.05).ConclusionsUsing a simultaneous segmental translation technique, deformity correction can be achieved with 23% fewer screws than maximal density screw pattern, but resulted in 25% higher bone-screw forces. Screw dropouts could be either on the convex side or on the concave side at alternate levels or at periapical levels. Periapical screw dropouts may more likely result in lower bone-screw force increase than alternate level screw dropouts.

Evaluating Accuracy of Free-hand Pedicle Screw Insertion in Adolescent Idiopathic Scoliosis Using Postoperative Multi-Slice Computed Tomography Scan

Background:Pedicle screw instrumentation has many advantages for correction of adolescent idiopathic scoliosis (AIS) deformity including better correction and fewer late complications. On the other hand, screw insertion in AIS is challenging. Intraoperative fluoroscopy or navigation techniques are expensive, time-consuming, and exposed to high radiation. Free-hand technique relies on the surgeon's experience and locating the pedicle entry point with anatomical landmarks. There are few studies that evaluated pedicle screw position accuracy with postoperative multi-slice computed tomography scan.Materials and Methods:We prospectively considered 38 consecutive AIS cases, who underwent corrective surgery with all pedicle screw technique. All the screws were inserted with free-hand technique using anatomic landmarks as a guide for an entry site. We divided pedicle penetration in medial, lateral, inferior, superior, and anterior vertebral body as Grades 0–4, that Grade 0 is fully contained within the pedicle, Grade 1 (<2 mm), Grade 2 (2.1–4 mm), Grade 3 (4.1–6 mm), and Grade 4 (>6 mm).Results:A total of 720 screws were inserted, of which 623 screws (86.5%) were perfect and 97 screws (13.5%) were misplaced. Of those which were misplaced, 39 screws (40.2%) were medial and 58 (59.8%) were lateral, which shows that the prevalence of lateral misplacement was more in comparison to medial misplacement. However, in all misplaced cases, the deviation of the screw was <2 mm (Grade 1). There was no misplacement in the inferior and superior.Conclusion:Pedicle screw insertion in AIS with the free-hand technique is a safe and reliable method.

Radiographic evaluation of posterior selective thoracolumbar or lumbar fusion for moderate Lenke 5C curves

IntroductionPosterior selective thoracolumbar or lumbar (TL/L) fusion with pedicle screw constructs for adolescent idiopathic scoliosis (AIS) has been studied in a few researches. However, few studies have discussed the indication for selective TL/L fusion and the behaviors of its adjacent disc angle. The present study aims to discuss the indication for posterior selective TL/L fusion and the behavior of the adjacent disc angle.Methods45 consecutive cases of AIS undergoing posterior selective TL/L fusion were retrospectively evaluated, with an average follow-up of 36 months. Radiographs were reviewed to determine the coronal curve magnitude and the sagittal alignment preoperatively, postoperatively and at final follow-up. Thoracic curves in groups A had a correction loss of more than 5°, while thoracic curves in group B had a correction loss of not more than 5°.ResultsThe coronal curve magnitude of the TL/L curve averaged 44° preoperatively and it was corrected to 6° immediately with a correction rate of 84.8 %. At final follow-up it was 9° with a correction loss of 3°. The minor thoracic curve was 26° preoperatively, and the convex side bending curve magnitude averaged 8° with a flexibility of 72.7 %. It was corrected to 13° immediately with a spontaneous correction of 48.5 %. At final follow-up it was 14° with a correction loss of 1°. UIVA decreased from 4° to 2° after surgery, and it was 2° at final follow-up. LIVA decreased from 7° to 4° after surgery, and it was 5° at final follow-up. Maximal correction of TL/L curves in group A is significantly less than that in group B. 1 patient received revision surgery to fuse the progressive thoracic curve.ConclusionPosterior selective TL/L fusion with pedicle screw constructs allows for spontaneous thoracic correction and maintains coronal and sagittal balance during the follow-up. Maximal correction instead of undercorrection was recommended for moderate Lenke 5C curves. Disc wedging could be improved after surgery and well maintained during the follow-up.

Video-Assisted Thoracoscopic Surgery (VATS) for Anterior Release of Rigid Thoracic Scoliosis

Introduction Standard anterior approach to the dorsal spine using thoracotomy carries a great morbidity; video-assisted thoracic surgery (VATS) has been used as a less invasive approach for many intrathoracic disease processes; among which anterior releases in rigid dorsal scoliosis. The authors performed (VATS) in patients with Adolescent Idiopathic Scoliosis (AIS), attempting to reduce the morbidity attributable to standard open thoracotomy surgery for anterior curve release; reporting their experience with thoracoscopy as part of the treatment for adolescent idiopathic scoliosis with rigid thoracic curves. Material and Method: A prospective randomized study of 34 cases of AIS with rigid thoracic curves underwent VATS for anterior release surgery between March 2008 and April 2013 was performed. The ages of the patients ranged from 11 to 27 years with a mean of 16.3 +/− 4.2 SD years. Spinal flexibility was assessed by the fulcrum bending technique. Cobb angle before and after the anterior release was compared. All patients had an anterior spinal release and posterior spinal fusion at two separate surgeries to evaluate the flexibility after anterior release without posterior instrumentation. Results The average follow up ranged from 22.3 to 39.2 months (mean 30.33 +/− 4.64 SD months). The mean preoperative Cobb angle was 78.4° +/− 8.87° SD on standing radiographs and 70.3° +/− 8.48° SD with the fulcrum-bending radiograph. After anterior release, the fulcrum bending radiograph showed reduction of mean Cobb angle to mean angle of 41.6° +/− 6.98°. The mean fulcrum bending flexibility index was improved from 10.41% +/− 3.97 SD (prior to VATS release) to 46.97% +/− 5.23 SD after release. VATS was successfully completed in all patients without major morbidities. The mean operative time for the anterior procedure was 123.96 minutes +/− 28.77 SD. The average number of excised discs was four. Conclusion Anterior spinal release using VATS may reduce postoperative morbidity and produces satisfactory degree of flexibility for rigid thoracic curves. It can be considered as a good and safe alternate to open thoracotomy for anterior release.

Postoperative Evaluation of Sagittal Spinal Balance in Lenke 1A and 5C Type of Adolescent Idiopathic Scoliosis: A Prospective Study

Introduction The aim of the study to evaluate the effect on sagittal spinal balance parameters postoperatively between short segment Bone-On-Bone anterior spinal fusion (ASF) and selective posterior spinal fusion (PSF) treated adolescent idiopathic scoliosis (AIS) (Lenke1A &amp; 5C) patients. Material and Methods This prospective study evaluates radiographs (lateral and AP view) for sagittal spinal balance parameters pre and postoperatively on 36 AIS (Lenke1A &amp; 5C) patients, who were divided into two groups of 18 each according to the treatment underwent in a single clinical institute since 2006–2013. Group 1 underwent short segment Bone-On-Bone ASF (mean age 17 years, 12–25) and Group 2 with selective PSF (mean age 16 years, 12–27). Results In Group 1, lumbar lordosis and sacral slope decreased (mean pre-op 50.4 &amp; 38.6 to mean post-op 36.0 &amp; 35.4), pelvic tilt increased (mean pre-op 12.8 to mean post-op 14.5), whereas thoracic kyphosis and pelvic incidence were similar enough to pre-op values. In Group 2, lumbar lordosis, sacral slope, pelvic incidence and pelvic tilt were decreased(mean pre-op 41.9, 35.5, 56.1 &amp; 16.0 to mean post-op 34.1, 29.7, 52.7 &amp; 12.1), whereas thoracic kyphosis similar enough to pre-op value. Conclusion According to our study, no significant difference found in sagittal spinal balance parameters postoperatively on radiographs between two groups except with slight decrease in lumbar lordosis post-op mean value in both groups. So, our study suggest that short segment Bone-On-Bone ASF and selective PSF procedures do not affect the sagittal spinal balance significantly in the treatment of Lenke1A and 5C type AIS cases postoperatively.

Post-operative shoulder imbalance in adolescent idiopathic scoliosis: a study of clinical photographs.

Study designRetrospective observational study.ObjectiveTo assess what features determine post-operative shoulder asymmetry in Adolescent Idiopathic Scoliosis (AIS).Summary of background dataShoulder balance is one of the major determinants of the cosmetic outcomes of AIS surgery. Yet, other than level of the shoulders we are not clear what parameters are to be measured to assess torso symmetry. This study looks at the various features that might affect the appearance of the shoulder region.MethodsThe records of 157 operated cases of AIS were retrospectively reviewed. Eight patients with documented post-operative shoulder asymmetry and were dissatisfied with their cosmetic outcomes were selected for the study. Their clinical photographs alone were studied. Three regions- the base of the neck, the shoulder and upper arm region- were analysed separately. Four measures each for the neck and shoulder and two for the arms were documented. No statistical tools were employed since the numbers were quite small but consensus was obtained between two Consultant Orthopaedic surgeons regarding the cosmetic impact of each parameter.ResultsThe neck and the shoulder appeared independent determinants of cosmesis of the proximal trunk. The base of neck symmetry seemed to be dependent on four features viz. centralization of the neck, neck tilt, trapezius angle and base of neck angle. The appearance of the shoulder itself depended on its level, axillary fold level, scapular level and the scapular prominence. The upper arm parameters appeared less critical in determining the cosmetic impact.ConclusionsProximal trunk symmetry in AIS depends on the symmetry of the base of the neck and shoulder regions. The level of the shoulders, axillary folds along with the base of neck angle, Trapezius angle appear to be key determinants of symmetry.

A polygenic burden of rare variants across extracellular matrix genes among individuals with adolescent idiopathic scoliosis.

Adolescent idiopathic scoliosis (AIS) is a complex inherited spinal deformity whose etiology has been elusive. While common genetic variants are associated with AIS, they explain only a small portion of disease risk. To explore the role of rare variants in AIS susceptibility, exome sequence data of 391 severe AIS cases and 843 controls of European ancestry were analyzed using a pathway burden analysis in which variants are first collapsed at the gene level then by Gene Ontology terms. Novel non-synonymous/splice-site variants in extracellular matrix genes were significantly enriched in AIS cases compared with controls (P = 6 × 10(-9), OR = 1.7, CI = 1.4-2.0). Specifically, novel variants in musculoskeletal collagen genes were present in 32% (126/391) of AIS cases compared with 17% (146/843) of in-house controls and 18% (780/4300) of EVS controls (P = 1 × 10(-9), OR = 1.9, CI = 1.6-2.4). Targeted resequencing of six collagen genes replicated this association in combined 919 AIS cases (P = 3 × 10(-12), OR = 2.2, CI = 1.8-2.7) and revealed a highly significant single-gene association with COL11A2 (P = 6 × 10(-9), OR = 3.8, CI = 2.6-7.2). Importantly, AIS cases harbor mainly non-glycine missense mutations and lack the clinical features of monogenic musculoskeletal collagenopathies. Overall, our study reveals a complex genetic architecture of AIS in which a polygenic burden of rare variants across extracellular matrix genes contributes strongly to risk.

Lenke 5C Curves in Adolescent Idiopathic Scoliosis: Anterior vs Posterior Selective Fusion.

The optimal treatment of Lenke 5C curves in adolescent idiopathic scoliosis is still unclear. To compare the outcomes and the spontaneous correction behavior between anterior and posterior selective fusion techniques in a large case series. Demographic and surgical data for patients with Lenke 5C curves treated with anterior or posterior fusion were collected from July 2002 to September 2011. Clinical assessment and radiographic parameters were compared preoperatively and postoperatively and at a minimum of 2 years of follow-up. Fifty-three Lenke 5C adolescent idiopathic scoliosis cases with an average follow-up of 4 years (range, 2-9.6 years) were included. The clinical scores were similar between the 2 groups. Postoperative major thoracic curvature changes were similar. The minor thoracic curve demonstrated a higher spontaneous correction rate in the posterior group. At follow-up, the minor thoracic curve showed a greater loss of correction in the posterior group, and finally both groups were comparable. Surgical time, intraoperative blood loss, and complications were comparable. A total of 5 patients had a final thoracic curve larger than the preoperative degrees. Selective fusion of the major thoracolumbar/lumbar curve in Lenke 5C adolescent idiopathic scoliosis can be achieved by anterior and posterior techniques. The spontaneous correction of the unfused thoracic curve was comparable after an average of 4 years follow-up.

Polymorphism of rs2767485 in Leptin Receptor Gene is Associated With the Occurrence of Adolescent Idiopathic Scoliosis.

A genetic association study of leptin receptor (LEPR) gene with adolescent idiopathic scoliosis (AIS) in the Chinese Han population. To determine whether LEPR gene polymorphisms are associated with the predisposition and/or disease severity of AIS. Patients with AIS were reported to have lower body mass index (BMI), abnormal leptin bioavailability, and systemic lower bone mass, which implied that leptin/LEPR signaling pathway may be implicated in the etiology of AIS. Previous association study of the polymorphisms in leptin gene did not show significant differences between AIS cases and controls. However, no study has been done to investigate the relationship between genetic polymorphisms of the LEPR gene and susceptibility to AIS. 570 patients with AIS aged 10 to 18 years were enrolled, and 570 age-matched healthy subjects were recruited as controls. 6 single nucleotide polymorphisms (SNPs) (rs1137101, rs1137100, rs4655555, rs2767485, rs1751492, and rs8179183) of LEPR gene were selected. The polymorphisms were genotyped using the polymerase chain reaction (PCR)-based Invader assay. Case-control study was performed to define the contribution of the 6 SNPs to predisposition of AIS. 1-way analysis of variance (ANOVA) test was used to compare the mean Cobb angles and BMI among patients with different genotypes in case-only analyses. Statistical significance was set at P < 0.05. Both the genotype and allele frequencies of SNP rs2767485 were significantly different between the patient with AIS and the control groups. No significant difference of allele frequency was noted in other 5 SNPs between the patients with AIS and the normal controls. Both the mean maximum Cobb angles and BMI of different genotype AIS groups were similar to each other for all the 6 SNPs (P > 0.05). Polymorphism of rs2767485 in LEPR gene is associated with the occurrence of AIS, suggesting LEPR is a predisposition gene.

The Association of rs4753426 Polymorphism in the Melatonin Receptor 1B (MTNR1B) Gene and Susceptibility to Adolescent Idiopathic Scoliosis: A Systematic Review and Meta-analysis

Background: Adolescent idiopathic scoliosis (AIS) is a tridimensional structural deformity of the spine that may deteriorate progressively, leading to significant functional limitations and pain problems. Several previous studies have implicated the rs4753426 single nucleotide polymorphism in the melatonin receptor 1B (MTNR1B) gene in the etiology of AIS. However the sample sizes were limited and the findings of those studies were inconsistent. An overall assessment of the evidence supporting this association has not been previously conducted. Objectives: To provide a comprehensive assessment and synthesis of the currently available evidence on the association between rs4753426 and AIS. Study Design: A systematic review and meta-analysis. Setting: University hospital, China. Methods: This review followed the Preferred Reporting Items for Systematic Review and MetaAnalyses guidelines. PubMed (MEDLINE), EMBASE, Scopus databases, and WANFANG databases were systematically searched through December 2014 to identify relevant studies following a sensitive strategy. Statistical analysis was performed using the Review Manager 5.2 software. Summary odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were estimated using the fixed-effect inverse variance model for allelic (C vs. T) and genotypic comparisons. Results: Four papers including 5 studies which involved 2,552 AIS cases and 2,738 controls were identified for this meta-analysis. The results showed that C allele of the rs4753426 was significantly associated with AIS (OR = 1.12, 95% CI: 1.03 – 1.21, P = 0.01). CT and CC genotypes were 26% (OR = 1.26, 95% CI: 1.04 – 1.53, P = 0.01) and 28% (OR = 1.28, 95% CI: 1.05 – 1.56, P = 0.01), respectively, more likely to have AIS compared with CC genotype. As for the dominant model (CC+TT vs. TT), summary ORs showed statistically significant association with AIS (OR = 1.28, 95% CI: 1.06 – 1.53, P = 0.009). Compared with the CT+TT genotype, the summary ORs of the CC genotype showed marginally statistically significant association with AIS (OR = 1.11, 95 % CI: 0.99 – 1.24, P = 0.07). The subgroup meta-analysis results showed the C allele and each genotype were significantly associated with AIS in the Asian group but not in the Caucasian group. Limitations: Paucity of available literature. Conclusions: To our knowledge, there has been no meta-analysis to analyze the association between rs4753426 polymorphism in the MTNR1B gene and AIS. This systematic review was a comprehensive analysis of the currently available evidence, and found an overall significant association of rs4753426 polymorphism with the risk of AIS, especially in the Asian population. Further investigation of this association is necessary in other populations. Key words: Adolescent idiopathic scoliosis, MTNR1B, Rs4753426, single nucleotide polymorphism, occurrence, curve severity, meta-analysis

Genetic Risk for Aortic Aneurysm in Adolescent Idiopathic Scoliosis.

Scoliosis is a feature of several genetic disorders that are also associated with aortic aneurysm, including Marfan syndrome, Loeys-Dietz syndrome, and type-IV Ehlers-Danlos syndrome. Life-threatening complications of aortic aneurysm can be decreased through early diagnosis. Genetic screening for mutations in populations at risk, such as patients with adolescent idiopathic scoliosis, may improve recognition of these disorders. The coding regions of five clinically actionable genes associated with scoliosis (COL3A1, FBN1, TGFBR1, TGFBR2, and SMAD3) and aortic aneurysm were sequenced in 343 adolescent idiopathic scoliosis cases. Gene variants that had minor allele frequencies of <0.0001 or were present in human disease mutation databases were identified. Variants were classified as pathogenic, likely pathogenic, or variants of unknown significance. Pathogenic or likely pathogenic mutations were identified in 0.9% (three) of 343 adolescent idiopathic scoliosis cases. Two patients had pathogenic SMAD3 nonsense mutations consistent with type-III Loeys-Dietz syndrome and one patient had a pathogenic FBN1 mutation with subsequent confirmation of Marfan syndrome. Variants of unknown significance in COL3A1 and FBN1 were identified in 5.0% (seventeen) of 343 adolescent idiopathic scoliosis cases. Six FBN1 variants were previously reported in patients with Marfan syndrome, yet were considered variants of unknown significance based on the level of evidence. Variants of unknown significance occurred most frequently in FBN1 and were associated with greater curve severity, systemic features of Marfan syndrome, and joint hypermobility. Clinically actionable pathogenic mutations in genes associated with adolescent idiopathic scoliosis and aortic aneurysm are rare in patients with adolescent idiopathic scoliosis who are not suspected of having these disorders, although variants of unknown significance are relatively common. Routine genetic screening of all patients with adolescent idiopathic scoliosis for mutations in clinically actionable aortic aneurysm disease genes is not recommended on the basis of the high frequency of variants of unknown significance. Clinical evaluation and family history should heighten indications for genetic referral and testing.

Intra-operative MEP monitoring can work well in the patients with neural axis abnormality.

To explain the intra-operative transcranial motor evoked potential (MEP) monitoring can work well in patients with neural axis abnormality (NAA). One hundred eighteen consecutive NAA and 334 adolescent idiopathic scoliosis (AIS) patients who underwent spinal deformity surgery between June 2010 and April 2013 in our spine center were included. The MEP data including the success rate of obtaining a baseline, amplitude, sensitivity and specificity were analyzed. High-efficiency MEPs baseline could be obtained in 117/118 NAA (74 congenital scoliosis, 32 neuromuscular scoliosis, 8 adult scoliosis, 3 congenital kyphoscoliosis and 1 neurofibromatosis scoliosis) and 334 AIS cases. They had an approximate level in success rate of MEPs baseline (99.2 vs. 99.7%) and MEPs amplitude (317μV, n=118; vs. 312μV, n=334). The sensitivity and specificity for MEP were 100 and 98.2% in patients with NAA. And the MEPs amplitude value fitted positive-skewed distribution in both of NAA and AIS. Intraoperative MEP monitoring can be used accurately and satisfactorily in NAA patients and show no difference compared with AIS.

Abnormalities in primary cilium of osteoblasts of adolescent idiopathic scoliosis patients

Adolescent Idiopathic Scoliosis (AIS) is a common complex genetic disease and one of the most prevalent childhood deformities. AIS is clinically characterized by a 3D spinal deformity with unknown cause. The aim of this study is to identify rare genetic variants and associated biological pathways involved in AIS onset and its progression. We recently completed exome sequencing of 69 AIS cases vs. 70 matched controls in a French-Canadian AIS cohort using SOLiD 5 technology. Results showed two gene families with significant enrichment for single nucleotide variants (SNVs) involved in cilia signalling pathways. To investigate the functional effect of these SNVs, we explored biomechanical responses on osteoblasts from AIS patients carrying these SNVs. More specifically, we applied a sinusoidal/oscillatory fluid flow at 2Pa, 0.5Hz for 90min using parallel plate flow chamber. Preliminary qPCR results of the cells post flow showed a significant increase (+10-folds) in the expression of cyclooxygenase-2 (COX2) in AIS cells versus control ones. Interestingly, microscopy imaging of the same cells revealed a 30% increase in the length of cilia (p<0.01) of AIS cells when compared to control ones. Of note, increased COX2 expression has been reported as a flow mediated response for bone cells. Our results suggest an increased sensitivity of AIS bone cells to fluid flow due to the elongation of cilia. Although cilia abnormalities have never been investigated in idiopathic scoliosis, ciliary structural and functional abnormalities in AIS osteoblasts might be involved in the onset and progression of the disease. More extensive experiments are currently underway to confirm the role of cilia in AIS pathogenesis.

High Density Pedicle Screws through Posterior Only Approach for Surgical Correction of Severe Adolescent Idiopathic Scoliosis &gt; 70o

Background Data: The classic treatment of severe rigid adolescent idiopathic scoliosis (AIS) was performed by combined anterior and posterior surgery which carries higher morbidity to the patient. Recently, posterior only surgery using allpedicle screws has been used for treatment of severe AIS with many advantages over combined approaches.Purpose: To evaluate the safety and effectiveness of high density pedicle screws through posterior only approach in correction of severe cases of adolescent idiopathic scoliosis (AIS) with curves > 70o. Study Design: Prospective cohort study. Patients and Methods: Between 2012 and 2014, fourteen patients were surgically treated for severe AIS with curves > 70o and were prospectively followed up for a minimum of 1 year (Range 1-4 years). Clinical outcomes were evaluated using SRS- 22 questionnaire. All patients were classified according to Lenke et al classification.Major and minor curves Cobb angle as well as sagittal parameters were measured on whole spine X-rays. Side bending films were used to assess curve flexibility. High density pedicle screws and multiple Ponte osteotomies were used in all patients. Five patients required asymmetrical pedicle subtraction osteotomy due to very rigid curve. Results: This study included 14 patients (8 females, 6 males).The mean age at time of surgery was 17.4 years (range 14-24 years). The mean correction rate for the coronal Cobb angle of the major and minor curves was 73.7% (80.4o preoperativeand 21.7o postoperative) and 68.7% (51.5o preoperative and 19.63o postoperative) respectively. The mean thoracic kyphosis angle was 44.2o preoperatively, 28.55o postoperatively and 28.1o at latest follow up. The mean SRS-22 questionnaire scores improved significantly from 2.8 preoperatively to 3.7 at the final follow up (P>0.001). No cases of pseudarthrosis, metal failure or neurological deficits were encountered. One patient with asymmetrical PSO developed hemothorax that was managed with chest tube insertion and follow up. Conclusion: High density pedicle screws through posterior only approach is a safe and effective method in treatment of severe AIS. It can achieve coronal curve correction comparable to combined anterior and posterior approaches without the morbidity of combined approaches. It also restores the sagittal profile leading to good functional outcomes and better quality of life. (2014ESJ073)

A rule-based algorithm can output valid surgical strategies in the treatment of AIS.

Variability in surgical strategies for the treatment of adolescent idiopathic scoliosis (AIS) has been demonstrated despite the existence of classifications to guide selection of AIS curves to include in fusion. Decision trees and rule-based algorithms have demonstrated their potential to improve reliability of AIS classification because of their systematic approach and they have also been proposed in algorithms for selection of instrumentation levels in scoliosis. Our working hypothesis is that a rule-based algorithm with a knowledge base extracted from the literature can efficiently output surgical strategies alternatives for a given AIS case. Our objective is to develop a rule-based algorithm based on peer-reviewed literature to output alternative surgical strategies for approach and levels of fusion. A literature search of all English Manuscripts published between 2000 and December 2009 with Pubmed and Google scholar electronic search using the following keywords: "adolescent idiopathic scoliosis" and "surgery" alternatively with "levels of fusion" or "approach". All returned abstracts were screened for contents that could contain rules to include in the knowledge base. A dataset of 1,556 AIS cases treated surgically was used to test the surgical strategy rule-based algorithm (SSRBA) and evaluate how many surgical treatments are covered by the algorithm. The SSRBA was programmed using Matlab. Descriptive statistic was used to evaluate the ability of the rule-based algorithm to cover all treatment alternatives. A SSRBA was successfully developed following Lenke classification's concept that the spine is divided into three curve segments [proximal thoracic (PT), main thoracic (MT) and thoracolumbar/lumbar (TL)]. Each of the 1,556 AIS patients in the dataset was ran through the SSRBA. It proposed an average of 3.78 (±2.06) surgical strategies per case. Overall, the SSRBA is able to match the treatment offered by the surgeon in approach and level of fusion 70% of the time (with one vertebral level leeway). This study is to the author's knowledge the first attempt at proposing an algorithm to output all surgical alternatives for a given AIS case. It uses a rule-based algorithm with a knowledge base extracted from peer-reviewed literature in an area with great variability. When tested against a database of AIS patients treated surgically, the SSRBA developed has the ability to propose a surgical plan with respect to approach and levels of fusion that match the surgeon's plan in a great majority of cases. Since this SSRBA seems to output multiple valid surgical strategies, it could allow the comparisons of various strategies and the outcomes achieved in similar cases in large databases for a given case and guide surgical treatment.

Patterns of shoulder imbalance in adolescent idiopathic scoliosis: a retrospective observational study.

Retrospective cohort study. To study the relationship between the proximal spine and shoulder levels in adolescent idiopathic scoliosis (AIS). It has been frequently observed that the shoulder levels do not correspond to the spinal curve direction in AIS. Eighty-five operated cases of AIS were analyzed retrospectively of which 69 were Lenke type I and II curves. Preoperative anteroposterior standing x-rays of the spine and clinical photographs were studied. T1 tilt and intercoracoid line (ICL) tilt and their mutual relationship were documented. The curve type (Lenke), magnitude, and direction of the proximal and main thoracic (PT and MT) curves were also noted. The shoulder level as depicted by the ICL showed 3 patterns-horizontal, left side elevated, or right side elevated. The T1-ICL relationship was either concordant or discordant. In the concordant case the T1 was tilted to the same side as the ICL; and vice versa in the discordant. The shoulder level was dependent on the MT curve if the ICL tilted to the same side as the MT curve and it was dependent on the PT curve if it tilted to the same side as the PT curve. This relationship appeared unrelated to curve type. Preoperative shoulder levels in AIS may be concordant with the T1 or discordant-each can have left or right shoulder elevation or balanced shoulders. Further, the shoulder might be MT dependent or PT dependent. Theoretically therefore, surgical balancing of the shoulder and upper instrumented vertebra placement should not depend only on the magnitude and stiffness of the PT curve.

Association between the ESR1 -351A>G single nucleotide polymorphism (rs9340799) and adolescent idiopathic scoliosis: a systematic review and meta-analysis.

A single nucleotide polymorphism in the promoter region of the estrogen receptor alpha gene (ESR1), rs9340799, has been linked with adolescent idiopathic scoliosis (AIS) in several association studies with limited sample size and inconsistent findings. A systematic review can provide a comprehensive appraisal of literature evidence and a meta-analysis can obtain a more precise estimate of any association. The purpose of the present study was to assess and synthesize the currently available evidence on the association between rs9340799 and AIS by conducting a systematic review and meta-analysis. This review followed the Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines. PubMed (MEDLINE), EMBASE, Scopus and HuGE Literature Finder databases were systematically searched to identify relevant studies following a sensitive strategy. Summary odds ratios and corresponding 95% confidence intervals (95 % CI) were estimated using the fixed-effect inverse variance model for allelic (G vs. A) and genotypic comparisons. Meta-analysis of four studies (n = 1,827 AIS cases and n = 1,253 controls) found a non-significant association between rs9340799 and AIS (allelic odds ratio 1.09, 95 % CI 0.96-1.23, p = 0.17). When examined in isolation, the rs9340799 polymorphism does not appear to be a likely susceptibility variant for AIS predisposition. However, rs9340799 may be associated with AIS severity, progression and treatment; further investigation is necessary to confirm these potential associations.

Positioning thoracic pedicle screw entry point using a new landmark: a study based on 3-dimensional computed tomographic scan.

A novel method to identify the entry point. To quantify the position of thoracic pedicle screw entry points on the lamina at various segments of the thoracic vertebrae in normal subjects and patients with adolescent idiopathic scoliosis and propose a new technique to select entry points using a new landmark. Thoracic pedicle screws have been widely used in thoracic surgery, and the placement of pedicle screws has been studied extensively. However, there are only qualitative studies on selecting the entry point, and no study has quantified the position of entry points. A retrospective study using 3-dimensional computed tomographic reconstruction techniques were used to study the morphology of thoracic vertebrae in 110 adolescents (56 cases of adolescent idiopathic scoliosis and 54 normal subjects). A quantitative area was used to select the entry point. Thoracic pedicle screw entry point was determined using the new landmark as reference and thoracic pedicle screws were placed in 21 patients. Postoperative computed tomographic scanning was performed to assess the safety and effectiveness of this entry point selection technique. We determined that the accuracy of pedicle screw placing after positioning entry point using the quantitative area was significantly superior to that after positioning entry point using the traditional method (P < 0.05). The new technique quantifies the position of each thoracic pedicle screw entry point and it is convenient, easy to operate, and has relatively high accuracy of screw placement. This positioning technique can provide safe and accurate clinical guidance for selecting thoracic pedicle screw entry point.

Intraoperative Push–Prone Test

A retrospective review of 24 cases of adolescent idiopathic scoliosis (AIS). Intraoperative push-prone test to determine the lowest instrumented vertebrae (LIV). To determine the LIV using intraoperative push-prone test. Determination of the LIV in surgical treatment of the AIS remains controversial. Different classifications schemes have been proposed to help surgeons in making this decision. Most schemes depend on flexibility views. However, variability in technique of obtaining flexibility views and interpretation of these views in relation to the classification schemes make decision making in choosing the LIV difficult. An intraoperative push-prone image was used to determine LIV. We were able to stop 1 or 2 levels above the stable vertebra in most cases. All patients had a well-balanced thorax over the pelvis. Intraoperative push-prone test is a useful adjunct to predict the LIV in AIS.

Association of rs11190870 near LBX1 with adolescent idiopathic scoliosis in East Asians: a systematic review and meta-analysis

Background contextThe rs11190870 single nucleotide polymorphism in the 3'-flanking region of the LBX1 gene has been implicated in the etiology of adolescent idiopathic scoliosis (AIS). A thorough appraisal of the evidence supporting this association has not been previously attempted. PurposeTo provide a comprehensive assessment and synthesis of the currently available evidence on the association between rs11190870 and AIS. Study designA systematic review and meta-analysis. MethodsThis review followed the Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines. PubMed (MEDLINE), EMBASE, Scopus, and HuGE Literature Finder databases were systematically searched through November 2013 to identify relevant studies following a sensitive strategy. Summary odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were estimated using the fixed-effect inverse variance model for allelic (T vs. C) and genotypic comparisons. ResultsMeta-analysis of four studies conducted in East Asian populations (n=3,215 AIS cases and n=15,347 controls) found a highly statistically significant and robust association between rs11190870 and AIS. Comparison of summary ORs indicated a codominant model effect of the T allele. Carriers of the TC and TT genotypes were 69% (OR=1.69, 95% CI: 1.48–1.94, p<.001) and 162% (OR=2.62, 95% CI: 2.28–3.02, p<.001), respectively, more likely to have AIS compared with carriers of the CC genotype. ConclusionsBased on a comprehensive analysis of the currently available evidence, rs11190870 is likely a susceptibility variant for AIS in East Asians. Further investigation of this association is necessary in other populations.