Longitudinal impact of multi-segment spinal fixation surgery on mobility status and clinical outcomes in adult spinal deformity: a multicenter retrospective study.

PURPOSE: To investigate changes in postoperative mobility status in patients with ASD, and the determining factors that influence these changes and their impact on clinical outcomes, including the rate of home discharge and long-term mobility. METHODS: A total of 299 patients with ASD who underwent multi-segment posterior spinal fusion were registered in a multi-center database were investigated. Patient mobility status was assessed using walking aids and classified into five levels (1: independent, 2: cane, 3: walker, 4: assisted, and 5: wheelchair) preoperatively, at discharge, and after 2 years. We determined improvements or declines in the patient's mobility based on changes in the classification levels. The analysis focused on the factors contributing to the deterioration of postoperative mobility. RESULTS: Two years postoperatively, 87% of patients maintained or improved mobility. However, 27% showed decreased mobility status at discharge, associated with a lower rate of home discharge (49% vs. 80% in the maintained mobility group) and limited improvement in mobility status (35% vs. 5%) after 2 years. Notably, postoperative increases in thoracic kyphosis (7.0 ± 12.1 vs. 2.0 ± 12.4°, p = 0.002) and lower lumbar lordosis (4.2 ± 13.1 vs. 1.8 ± 12.6°, p = 0.050) were substantial factors in mobility decline. CONCLUSION: Postoperative mobility often temporarily decreases but generally improves after 2 years. However, an overcorrection in sagittal alignment, evidenced by increased TK, could detrimentally affect patients' mobility status. Transient mobility decline associated with overcorrection may require further rehabilitation or hospitalization. Further studies are required to determine the biomechanical effects of surgical correction on mobility.

Does global spinal alignment affect the use of walking aids after multi-segment spinal fixation for patients with ASD? A multicenter retrospective study.

PURPOSE: This study aimed to clarify the relation between global spinal alignment and the necessity of walking aid use in patients with adult spinal deformity (ASD) and to investigate the impact of spinal fixation on mobility status after surgery. METHODS: In total, 456 older patients with ASD who had multi-segment spinal fixation surgery and were registered in a multi-center database were investigated. Patients under 60 years of age and those unable to walk preoperatively were excluded. Patients were classified by their mobility status into the independent, cane, and walker groups. Comparison analysis was conducted using radiographic spinopelvic parameters and the previously reported global spine balance (GSB) classification. In addition, preoperative and 2 years postoperative mobility statuses were investigated. RESULTS: Of 261 patients analyzed, 66 used walking aids (canes, 46; walkers, 20). Analysis of preoperative radiographical parameters showed increased pelvic incidence and pelvic incidence-lumbar lordosis mismatch in the walker group and increased sagittal vertebral axis in the cane and walker groups versus the independent group. Analysis of GSB classification showed a higher percentage of walker use in those with severe imbalance (grade 3) in the sagittal classification but not in the coronal classification. While postoperative radiographical improvements were noted, there was no significant difference in the use of walking aids before and 2 years after surgery (P = 0.085). CONCLUSION: A significant correlation was found between "sagittal" spinal imbalance and increased reliance on walking aids, particularly walkers. However, the limitation of improvement in postoperative mobility status suggested that multiple factors influence the mobility ability of elderly patients with ASD.

Preoperative low Hounsfield units in the lumbar spine are associated with postoperative mechanical complications in adult spinal deformity.

PURPOSE: To determine the most valid bone health parameter to predict mechanical complications (MCs) following surgery for adult spinal deformity (ASD). METHODS: This multicenter study retrospectively examined the records of patients who had undergone fusion of three or more motion segments, including the pelvis, with a minimum two-year follow-up period. Patients with moderate and severe global alignment and proportion scores were included in the study and divided into two groups: those who developed MCs and those who did not. Bone mineral density (BMD) of the lumbar spine and femoral neck was measured using dual-energy X-ray absorptiometry, and Hounsfield units (HUs) were measured in the lumbar spine on computed tomography. Radiographic parameters were evaluated preoperatively, immediately after surgery, and at final follow-up. RESULTS: Of 108 patients, 30 (27.8%) developed MCs, including 26 cases of proximal junctional kyphosis/failure, 2 of distal junctional failure, 6 of rod fracture, and 11 reoperations. HUs were significantly lower in patients who experienced MCs (113.7 ± 41.1) than in those who did not (137.0 ± 46.8; P = 0.02). BMD did not differ significantly between the two groups. The preoperative and two-year postoperative global tilt, as well as the immediately postoperative sagittal vertical axis, were significantly greater in patients who developed MCs than in those who did not (P = 0.02, P < 0.01, and P = 0.01, respectively). CONCLUSION: Patients who experienced MCs following surgery for ASD had lower HUs than those who did not. HUs may therefore be more useful than BMD for predicting MCs following surgery for ASD.

Evidence of causality of low body mass index on risk of adolescent idiopathic scoliosis: a Mendelian randomization study.

Introduction: Adolescent idiopathic scoliosis (AIS) is a disorder with a three-dimensional spinal deformity and is a common disease affecting 1-5% of adolescents. AIS is also known as a complex disease involved in environmental and genetic factors. A relation between AIS and body mass index (BMI) has been epidemiologically and genetically suggested. However, the causal relationship between AIS and BMI remains to be elucidated. Material and methods: Mendelian randomization (MR) analysis was performed using summary statistics from genome-wide association studies (GWASs) of AIS (Japanese cohort, 5,327 cases, 73,884 controls; US cohort: 1,468 cases, 20,158 controls) and BMI (Biobank Japan: 173430 individual; meta-analysis of genetic investigation of anthropometric traits and UK Biobank: 806334 individuals; European Children cohort: 39620 individuals; Population Architecture using Genomics and Epidemiology: 49335 individuals). In MR analyses evaluating the effect of BMI on AIS, the association between BMI and AIS summary statistics was evaluated using the inverse-variance weighted (IVW) method, weighted median method, and Egger regression (MR-Egger) methods in Japanese. Results: Significant causality of genetically decreased BMI on risk of AIS was estimated: IVW method (Estimate (beta) [SE] = -0.56 [0.16], p = 1.8 × 10-3), weighted median method (beta = -0.56 [0.18], p = 8.5 × 10-3) and MR-Egger method (beta = -1.50 [0.43], p = 4.7 × 10-3), respectively. Consistent results were also observed when using the US AIS summary statistic in three MR methods; however, no significant causality was observed when evaluating the effect of AIS on BMI. Conclusions: Our Mendelian randomization analysis using large studies of AIS and GWAS for BMI summary statistics revealed that genetic variants contributing to low BMI have a causal effect on the onset of AIS. This result was consistent with those of epidemiological studies and would contribute to the early detection of AIS.

Identification of a Functional Susceptibility Variant for Adolescent Idiopathic Scoliosis that Upregulates Early Growth Response 1 (EGR1)-Mediated UNCX Expression.

Adolescent idiopathic scoliosis (AIS) is a serious health problem affecting 3% of live births all over the world. Many loci associated with AIS have been identified by previous genome wide association studies, but their biological implication remains mostly unclear. In this study, we evaluated the AIS-associated variants in the 7p22.3 locus by combining in silico, in vitro, and in vivo analyses. rs78148157 was located in an enhancer of UNCX, a homeobox gene and its risk allele upregulated the UNCX expression. A transcription factor, early growth response 1 (EGR1), transactivated the rs78148157-located enhancer and showed a higher binding affinity for the risk allele of rs78148157. Furthermore, zebrafish larvae with UNCX messenger RNA (mRNA) injection developed body curvature and defective neurogenesis in a dose-dependent manner. rs78148157 confers the genetic susceptibility to AIS by enhancing the EGR1-regulated UNCX expression. © 2022 American Society for Bone and Mineral Research (ASBMR).

Atypical Sotos syndrome caused by a novel splice site variant.

Sotos syndrome is usually caused by haploinsufficiency of NSD1; it is characterized by overgrowth, craniofacial features, and learning disabilities. We describe a boy with Sotos syndrome caused by a splicing variant (c.4378+5G>A). The clinical manifestations included severe connective tissue involvement, including joint hypermobility, progressive scoliosis, pectus deformity, and skin hyperextensibility; no overgrowth was observed.

Polygenic Risk Score of Adolescent Idiopathic Scoliosis for Potential Clinical Use.

Adolescent idiopathic scoliosis (AIS) is a common disease causing three-dimensional spinal deformity in as many as 3% of adolescents. Development of a method that can accurately predict the onset and progression of AIS is an immediate need for clinical practice. Because the heritability of AIS is estimated as high as 87.5% in twin studies, prediction of its onset and progression based on genetic data is a promising option. We show the usefulness of polygenic risk score (PRS) for the prediction of onset and progression of AIS. We used AIS genomewide association study (GWAS) data comprising 79,211 subjects in three cohorts and constructed a PRS based on association statistics in a discovery set including 31,999 female subjects. After calibration using a validation data set, we applied the PRS to a test data set. By integrating functional annotations showing heritability enrichment in the selection of variants, the PRS demonstrated an association with AIS susceptibility (p = 3.5 × 10-40 with area under the receiver-operating characteristic [AUROC] = 0.674, sensitivity = 0.644, and specificity = 0.622). The decile with the highest PRS showed an odds ratio of as high as 3.36 (p = 1.4 × 10-10 ) to develop AIS compared with the fifth in decile. The addition of a predictive model with only a single clinical parameter (body mass index) improved predictive ability for development of AIS (AUROC = 0.722, net reclassification improvement [NRI] 0.505 ± 0.054, p = 1.6 × 10-8 ), potentiating clinical use of the prediction model. Furthermore, we found the Cobb angle (CA), the severity measurement of AIS, to be a polygenic trait that showed a significant genetic correlation with AIS susceptibility (rg = 0.6, p = 3.0 × 10-4 ). The AIS PRS demonstrated a significant association with CA. These results indicate a shared polygenic architecture between onset and progression of AIS and the potential usefulness of PRS in clinical settings as a predictor to promote early intervention of AIS and avoid invasive surgery. © 2021 American Society for Bone and Mineral Research (ASBMR).

Comparison of Pulmonary Function After Selective Anterior Versus Posterior Fusion for the Correction of Thoracolumbar and Lumbar Adolescent Idiopathic Scoliosis.

STUDY DESIGN: Retrospective multicenter study. OBJECTIVES: To compare the selective anterior spinal fusion (ASF) versus posterior spinal fusion (PSF) on postoperative pulmonary function testing (PFT) whether thoracotomy with separation of the diaphragm by anterior approach influences the PFT in thoracolumbar and lumbar adolescent idiopathic scoliosis (AIS). METHODS: A multicenter series of AIS patients who underwent selective spinal fusion were retrospectively reviewed. Seventy-nine female patients were included (mean 15.8 years). There were 35 patients in the ASF group and 44 patients in the PSF group. Patient demographics, radiographic measurements, and PFT data from preoperative to 2-year follow-up were analyzed. RESULTS: Preoperatively, there were no significant differences in PFTs between the groups. The ASF group patients were more likely to undergo shorter fusions (4.5 instrumented vertebral levels) than those in the PSF group (5.2 levels). At 2-year follow-up, forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1) in ASF group were statistically lower than those in PSF group. When comparing preoperative and 2-year changes on each procedure, only %FVC showed significant difference in ASF while FVC, FEV1, and %FEV1 did not. Meanwhile, the ASF group showed a significant decrease in FVC at 6 and 12 months compared to preoperative values. In PSF group, there was a decrease at 6 months, returned to preoperative value at 1-year follow-up. CONCLUSIONS: Pulmonary function after ASF and PSF was similar at 2 years; however, anterior group did not return to the baseline at 6 months and 1 year suggesting anterior approach may affect early postoperative pulmonary function.

Excessive correction impacts postoperative shoulder imbalance in lenke type 5C adolescent idiopathic scoliosis.

BACKGROUND: Postoperative shoulder imbalance (PSI) has a negative impact on the surgical outcomes of patients with adolescent idiopathic scoliosis. This study aimed to evaluate the risk factors of PSI in patients with Lenke type 5C curves. METHODS: This study included 100 patients who underwent posterior correction surgery using pedicle screw constructs for Lenke type 5C curves. The mean age of the patients at surgery was 15.5 ± 2.3 years, and the mean follow-up period was 36.6 ± 15.0 months. The subjects were classified into the following two groups: PSI and non-PSI. Radiographic parameters, including the preoperative and 2-year postoperative coronal and sagittal profiles, were compared between the two groups. RESULT: PSI was found in eight patients (8.0%). The preoperative Cobb angles were 47.3° ± 8.7° and 48.0° ± 3.9° in the non-PSI and PSI groups, respectively. The correction rate in the PSI group was significantly higher than that in the non-PSI group (81.0% ± 17.7% vs. 67.7% ± 14.7%; p = 0.018). The preoperative T1 tilt angle in the PSI group was significantly larger than that in the non-PSI group (6.1° ± 3.3° vs. 3.1° ± 2.8°; p = 0.005). Receiver operating characteristic (ROC) analysis showed that the area under the ROC curve was 0.769 (p = 0.012, 95% confidence interval [CI], 0.556-0.982) and 0.763 (p = 0.014, 95% CI, 0.598-0.928) for the correction rate and preoperative T1 tilt, respectively. The cut-off value was 73% and 4° for the correction rate and preoperative T1, respectively. CONCLUSION: PSI was found in 8.0% of Lenke type 5C curves. Excessive correction of the lumbar curve of >73% and preoperative T1 tilt of >4° can be risk factors for PSI in patients with Lenke type 5C curve.

Genome-wide association study identifies 14 previously unreported susceptibility loci for adolescent idiopathic scoliosis in Japanese.

Adolescent idiopathic scoliosis (AIS) is the most common pediatric spinal deformity. Several AIS susceptibility loci have been identified; however, they could explain only a small proportion of AIS heritability. To identify additional AIS susceptibility loci, we conduct a meta-analysis of the three genome-wide association studies consisting of 79,211 Japanese individuals. We identify 20 loci significantly associated with AIS, including 14 previously not reported loci. These loci explain 4.6% of the phenotypic variance of AIS. We find 21 cis-expression quantitative trait loci-associated genes in seven of the fourteen loci. By a female meta-analysis, we identify additional three significant loci. We also find significant genetic correlations of AIS with body mass index and uric acid. The cell-type specificity analyses show the significant heritability enrichment for AIS in multiple cell-type groups, suggesting the heterogeneity of etiology and pathogenesis of AIS. Our findings provide insights into etiology and pathogenesis of AIS.

Modic changes and disc degeneration in adolescent idiopathic scoliosis patients who reach middle age without surgery: Can residual deformity cause lumbar spine degeneration?

BACKGROUND: We have yet to determine what types of lumbar degenerative changes can be observed on MRI in middle-aged adolescent idiopathic scoliosis (AIS) patients without undergoing surgery. The aims of this study were to investigate AIS patients who have reached middle age without undergoing surgery and to clarify if residual spinal deformities may have affected health-related quality of life (HRQOL) and lumbar spine degeneration. METHODS: Subjects comprised AIS patients who reached middle age without surgery and who underwent whole-spine X-rays, lumbar MRI, and SRS-22 surveys. Of the 60 cases collected from five scoliosis centers, 25 patients who met the inclusion criteria were enrolled into the residual deformity (RD) group and analyzed. Controls (CTR) group comprised 25 individuals matched for age, sex, and BMI with the patient group. RESULTS: MRI revealed no significant differences in the percentage of individuals with Pfirrmann grade 4 or 5 disc degeneration in 1 or more segments (RD group: 84%, CTR group: 60%, p = 0.059). Significantly more patients with Modic changes in 1 or more segments were observed in the RD group (RD group: 56%, CTR group: 8%, p < 0.001). All SRS-22 scores were significantly lower in the RD group. The lumbar curve cutoff point based on whether or not Modic change could be observed using ROC analysis was 39.5°. CONCLUSIONS: Compared to healthy individuals, AIS patients with residual deformity who have never had surgery showed similar prevalence of disc degeneration, but they had more Modic changes and poor HRQOL. The cutoff point for lumbar curves of patients with and without Modic changes in middle age was 39.5°.

A Replication Study for the Association of rs11190870 With Curve Severity in Adolescent Idiopathic Scoliosis in Japanese.

STUDY DESIGN: Case-only study. OBJECTIVE: The aim of this study was to confirm the association of rs11190870 with adolescent idiopathic scoliosis (AIS) severity in Japanese patients with AIS. SUMMARY OF BACKGROUND DATA: Although the association of rs11190870 with AIS susceptibility is replicated in multiple ethnics, the association of rs11190870 with curve severity is controversial. Since the previous studies are of small, we performed a replication study using far larger number of patients than previous studies. METHODS: A total of 1860 Japanese patients with AIS who had reached skeletal maturity or undergone surgical fusion were included in the study. We evaluated the association between rs11190870 and AIS progression for the entire group, and then for patients grouped according to a severe curve (a Cobb angle of ≥40°) or mild curve (a Cobb angle <30°). Because braces could affect the results of the present study, patients in the mild-curve group were divided according to whether or not they had worn a brace. We then evaluated associations between rs11190870 genotype and curve severity in these groups. RESULTS: The mean Cobb angles were 54.8°â€Š±â€Š12.1° in the severe-curve group and 24.4°â€Š±â€Š4.0° in the mild-curve group. The difference in rs11190870 risk-allele frequency between the severe- and mild-curve groups was evaluated. No significant differences were observed. We then examined the association of rs11190870 risk-allele frequency between patients in the mild- and severe-curve groups using the χ test for three models, and found a marginal association between rs11190870 and curve severity in the dominant model (P = 0.035, odds ratio = 1.51). CONCLUSION: We found no association between rs11190870 and curve severity using the criteria of previous study. However, we found a marginal association between rs11190870 and curve severity. Large-scale replication studies that consider skeletal maturity and brace history, including replication studies in other ethnic groups, would be helpful for clarifying the association. LEVEL OF EVIDENCE: 4.

Three-Dimensional Analysis of Hemimetameric Segmental Shift in Congenital Scoliosis.

STUDY DESIGN: This is a retrospective cohort study. BACKGROUND: Hemimetameric segmental shift (HMMS) is defined as a hemivertebral deformation in which 2 or more hemivertebrae exist on both sides of the spine and are separated by at least 1 normal vertebra. Reports of HMMS are rare and based on simple anterior x-ray images. No reports have used 3-dimensional computed tomography (3D-CT) to analyze both the anterior and posterior elements. The objective of this study was to analyze the morphology and clinical features of HMMS 3 dimensionally. METHODS: HMMS was confirmed in 32 (6.6%, 16 males and 16 females) of 483 patients diagnosed with congenital scoliosis at the study institution between 1998 and 2013. The average age at the first visit was 6 years and 3 months. 3D-CT imaging was performed for 30 patients older than 2 years (average age: 9 y and 8 mo) and used to classify cases according to posterior elements. RESULTS: With regard to the number of hemivertebrae present, 21 patients had 2 hemivertebrae, 7 patients had 3 hemivertebrae, and 2 patients had 4 hemivertebrae. Patients with 2 hemivertebrae predominantly had hemivertebrae in the thoracolumbar spine. Patients were classified into 2 categories: malformation existing at an equal level in anterior and posterior sides (unison HMMS) and malformation existing at nonequal levels (discordant HMMS). Nine patients had unison HMMS and all of them had 2 hemivertebrae (average: 4.6 vertebrae). Twenty-one patients had discordant HMMS, with 12 having 2 hemivertebrae, 7 having 3 hemivertebrae, and 2 having 4 hemivertebrae. CONCLUSIONS: Through 3D-CT analysis, HMMS was categorized as unison or discordant. Discordant HMMS was observed in 21 of 30 (70%) patients and in all patients with >3 hemivertebrae. Diagnosing HMMS, whether unison or discordant, is clinically important and should be done with careful analysis of bone models and/or radiologic images to determine the correct spinal levels. LEVEL OF EVIDENCE: Level IV-diagnostic study.

Clinical Characteristics and Thoracic factors in patients with Idiopathic and Syndromic Scoliosis Associated with Pectus Excavatum.

INTRODUCTION: The purpose of this study is to demonstrate the clinical characteristics and thoracic factors such as sternal tilt angle and Haller index in patients with idiopathic or syndromic scoliosis associated with pectus excavatum. METHODS: We performed a retrospective review on a cohort of 70 patients (37 males and 33 females) diagnosed with idiopathic and syndromic scoliosis associated with pectus excavatum between 1985 and 2014. We investigated age, location and Cobb angle of the main curve, and thoracic factors including sternal deviation and tilting angle and Haller index using radiographs and computed tomography of the chest. RESULTS: Patients' mean age at the first visit to our hospital was 10.3 years (1-18 years old). There were 41 patients with idiopathic scoliosis and 29 with syndromic scoliosis. Main curve locations were thoracic in 52 patients, thoracolumbar in 10, and lumbar in 8. The mean Cobb angle of the main curve was 45.0 degrees (11-109 degrees). The sternum was displaced on the left side in 72% of patients, central in 23%, and right in 5%. Mean sternal tilt angle was 12.4 degrees (2.3-34 degrees), and mean Haller index score was 4.9 (2.9-9.2). There was no significant correlation between Cobb angle and sternal tilt angle/Haller index. However, a significant difference was found between sternal tilt angle and Haller index. CONCLUSION: Most patients with both scoliosis and pectus excavatum have left side deviated sternum and a higher Haller index score; therefore this can negatively impact cardiac function. Prone positioning and the corrective force applied during scoliosis surgery as well as thoracic compression during cast or brace treatment may have a negative effect on cardiac function in these patients.

Evaluation of thoracic factors after scoliosis surgery in patients with both scoliosis and pectus excavatum.

PURPOSE: Pectus excavatum can negatively impact cardiac function during scoliosis surgery. Several authors reported severe hypotension associated with the prone position during scoliosis surgery in children that had both scoliosis and pectus excavatum. However, we could find no studies that evaluated the change in the thoracic factors, such as sternal tilt angle and Haller index after scoliosis surgery in patients with both scoliosis and pectus excavatum. The purpose of this study is to evaluate the change in thoracic factors after surgical treatment for scoliosis associated with pectus excavatum. METHODS: We performed a retrospective review on 20 patients (10 males and 10 females) who underwent surgical treatment for scoliosis associated with pectus excavatum from August 2004 to April 2014 in our hospital. We investigated the scoliosis diagnosis, preoperative and postoperative Cobb and thoracic kyphosis (TK) angles, the change in TK after surgery and thoracic factors, including the AP and transverse diameters of the chest, the sternal tilt angle, and Haller index. RESULTS: Patient mean age was 13.2 years old (4-27 years old) at surgery. Types of scoliosis were idiopathic in 8 patients, syndromic in 10, and neuromuscular in 2. The mean Cobb angles were 72.1° preoperatively and 19.0° postoperatively. Curve locations were thoracic in 13 patients, thoracolumbar in 4, and lumbar in 3. Surgical treatment of pectus excavatum was performed in 9 patients (45 %) before scoliosis treatment. Mean sternal tilt angles were 11.5° preoperatively and 11.1° postoperatively. Mean Haller indices were 4.8 preoperatively and 5.3 postoperatively. This was especially true for syndromic or neuromuscular scoliosis and thoracolumbar/lumbar curve type patients in which scoliosis surgery tended to worsen the Haller index. CONCLUSION: The Haller index increased postoperatively in 11 of 20 patients, which means sternal depression deteriorated after scoliosis surgery in about 50 % of patients. We suggest that surgeons fully assess the thoracic factors in patients with scoliosis and pectus excavatum prior to performing scoliosis surgery and carefully monitor their patient's general condition during surgery.

Intervertebral Disc Degeneration During Postoperative Follow-up More Than 10 Years After Corrective Surgery in Idiopathic Scoliosis: Comparison Between Patients With and Without Surgery.

STUDY DESIGN: A retrospective comparative study. OBJECTIVE: The aim of this study was to evaluate the difference in trends of disc degeneration (DD) at lower unfused segments (LUS) for postoperative patients who have gone through spinal instrumentation at 10-year follow-up with the natural progression of idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: Studies that used magnetic resonance imaging (MRI) state that DD rates at LUS are higher than in the normal population. However, current studies do not prove that surgery is the most effective clinical method to treat idiopathic scoliosis, as no existing report compares the rates of DD with the natural history of idiopathic scoliosis. METHODS: Female patients diagnosed of scoliosis were divided into three groups: 1) surgical group: postoperative 10-year patients with severe scoliosis before operation; 2) mild scoliosis group: with comparatively equal scoliosis to postoperative patients of the same age at 10 years follow-up; 3) severe scoliosis group: without any record of corrective surgery under the assumption that the scoliosis of the surgical group have progressed according to natural history. RESULTS: MRI findings of the surgical group show DD in 32 patients (62.7%) where the highest rate of DD occurred at L5/S. In the mild scoliosis group, 21 patients (47.7%) had DD, with higher rates at L4/5 and L5/S. DD was most common in L3/4 and L4/5 in the severe scoliosis group where 27 patients (81.8%) had DD. As such, DD rates were significantly higher in the severe scoliosis group than the surgical group at the same spinal level. The same was true for the existence of low back pain, where the severe scoliosis group had greater incidence of low back pain than the surgical group. CONCLUSION: Corrective surgeries were able to reduce the incidence of DD. Radiological analysis also suggests that surgical intervention is a clinically feasible treatment for idiopathic scoliosis patients. LEVEL OF EVIDENCE: 3.

A functional variant in MIR4300HG, the host gene of microRNA MIR4300 is associated with progression of adolescent idiopathic scoliosis.

Adolescent idiopathic scoliosis (AIS) is a common spinal deformity affecting millions of children. Since treatment and prognosis of AIS depend on curve progression, identifying factors related to AIS curve progression is important in its management. Although several genetic loci for AIS occurrence are reported, no locus for curve progression has been identified. To identify genes associated with AIS progression, we conducted a genome-wide association study followed by a replication study using a total of 2,543 AIS subjects who were evaluated for the curve progression. We identified a significantly associated locus on chromosome 11q14.1 (P = 1.98 × 10-9, odds ratio = 1.56). In silico and in vitro analyses identified a functional variant, rs35333564 in MIR4300HG, the host gene of a microRNA, MIR4300. The genomic region containing rs35333564 had enhancer activity, which was decreased in its risk allele. Our data suggest that decrease of MIR4300 is related to AIS progression.

Proximal Junctional Kyphosis Following Posterior Hemivertebra Resection and Short Fusion in Children Younger Than 10 Years.

STUDY DESIGN: A retrospective study. OBJECTIVE: To investigate whether proximal junctional kyphosis (PJK) or obvious proximal junctional angle (PJA) changes in the sagittal plane develops following short fusion in children younger than 10 years of age with congenital scoliosis, and to investigate the possible risk factors. SUMMARY OF BACKGROUND DATA: PJK following long spinal fusion in adolescents and adults is a serious postoperative complication. Although the same problem may occur in patients with early-onset scoliosis who have undergone spine fusion, few studies have been reported any relationship between PJK and spinal fusion in young children with congenital scoliosis. MATERIALS AND METHODS: Thirty-seven children treated in a single institution between 1998 and 2010 were reviewed retrospectively. The inclusion criteria included (1) younger than 10 years of age at the time of operation; (2) simple congenital deformity; (3) hemivertebra treated by posterior hemivertebrectomy with short fusion at a maximum of 5 motion segments; and (4) minimum follow-up for 2 years. The PJA from the caudal endplate of the upper instrumented vertebra (UIV) to the cephalad endplate of the vertebra adjacent to the UIV, thoracic kyphosis (T5-T12), lumbar lordosis (T12-S1), global sagittal balance, and magnitude of scoliosis of the major curves and upper compensated curves were measured on lateral radiographs. PJK was defined by a PJA>10 degrees during the follow-up and at least 10 degrees greater than the preoperative or early postoperative measurement. Wilcoxon tests were performed for statistical analysis. RESULTS: PJK occurred in 7 of 37 patients (18.9%), during an average of 4.5±3.2 years of follow-up (2-12 y). The UIV level of children with PJK was on T9 in 4 patients, and T11, T12, and L1 in 1. Screw malposition at UIV was confirmed by postoperative computed tomography images in 6 patients. Only 1 patient with a screw deviation did not develop PJK during the follow-up period. None of the patients with PJK was symptomatic, and no patients required revision surgery because of PJK. PJK occurred and progressed during the first 6 months after surgery followed by almost no progression or slight improvement in patients that could be followed up beyond 6 months postoperatively; in association with an increase of the lumbar lordosis. CONCLUSIONS: PJK occurred in pediatric patients with simple congenital deformities following hemivertebrectomy and short fusion. PJK was more common in patients with (1) greater immediately postoperative segmental kyphosis and PJA; (2) screw malposition on the UIV; and (3) hemivertebra located on the lower thoracic or the thoracolumbar region.

Corrective surgery for kyphosis in a case of Gaucher's disease without history of vertebral compression fractures.

INTRODUCTION: Gaucher's disease is a congenital metabolic disorder characterized by the accumulation of glucocerebroside in the reticuloendothelial system. Its clinical manifestations include splenomegaly, osteopenia, and pathological fractures. Cases of patients with kyphotic deformities caused by pathological vertebral compression fractures associated with Gaucher's disease are well reported. However, there has been no report regarding surgical treatment of kyphotic deformity caused by Gaucher's disease without compression fractures. In the present report, we describe surgical treatment for kyphotic deformity caused by Gaucher's disease without a past history of vertebral compression fractures. CASE REPORT: The patient was diagnosed with Gaucher's disease at the age of 15 months. The patient was a 10-year-old girl with progressive kyphosis (84° between T6 and L3, with T12 as the apical vertebra) without compression fractures. Although the patient had been treated using a brace since the age of 3 years, the kyphosis progressed to the point where corrective surgery was required. We initially performed T3-L3 posterior spinal fusion, followed by anterior fusion 3 months later, which corrected the kyphosis to 35°. Postoperatively, the patient suffered fractures of the upper and lower extremities but did not have spinal fractures. CONCLUSIONS: Two-stage anterior/posterior combined correction and fusion was performed in a patient with kyphotic deformity caused by Gaucher's disease without compression fractures. Because of bone fragility in Gaucher's disease, careful selection of the fusion range and postoperative therapy was necessary.

A Japanese nationwide multicenter survey on perioperative complications of corrective fusion for elderly patients with adult spinal deformity.

BACKGROUND: Recently, corrective fusion surgery for patients with adult spinal deformity (ASD) has become common in Japan. This study aimed to clarify the status of surgeries for ASD in Japan, focusing on perioperative complications. A nationwide multicenter survey gathering information on surgically treated ASD patients was conducted by the committee for Adult Spinal Deformity of the Japanese Scoliosis Society. METHODS: This study was a review of retrospectively collected data from 18 spine scoliosis centers belonging to the Japanese Scoliosis Society. Patients who underwent corrective fusion surgery for ASD between 2011 and 2013 were included. Demographics, comorbidities, surgical data, and complications were investigated. RESULTS: A total of 1192 patients (mean age, 57.7 years) were included in this study. Of these, 611 patients were aged less than 65 years and 581 patients were aged 65 years or greater. The age distribution had two peaks, in the third and eighth decades. Deformities caused by degeneration represented 67% of the pathology in patients aged over 65 years; however, non-degenerative disease such as adult idiopathic scoliosis and syndromic or congenital deformity represented over 60% of pathology in patients aged less than 65 years. The iatrogenic deformity and reoperation rates were both less than 3%. The mean operation time and estimated blood loss were 370 min and 1642 ml, respectively. Major perioperative complications occurred in 160 patients (14.5%). The incidence of complications was significantly higher in patients aged over 65 years, including neurological deficits, hemorrhagic shock, hematoma, heart failure, and surgical site infection (p < 0.05). CONCLUSIONS: Older (aged over 65 years) ASD patients showed greater rates of deformity due to the occurrence of degeneration and vertebral fractures, as well as a higher incidence of peri-and postoperative complications. Efforts to reduce perioperative complications are therefore imperative, especially for elderly ASD patients in our aging society.