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.

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.

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.

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.

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.

A Functional SNP in BNC2 Is Associated with Adolescent Idiopathic Scoliosis.

Adolescent idiopathic scoliosis (AIS) is the most common spinal deformity. We previously conducted a genome-wide association study (GWAS) and detected two loci associated with AIS. To identify additional loci, we extended our GWAS by increasing the number of cohorts (2,109 affected subjects and 11,140 control subjects in total) and conducting a whole-genome imputation. Through the extended GWAS and replication studies using independent Japanese and Chinese populations, we identified a susceptibility locus on chromosome 9p22.2 (p = 2.46 × 10(-13); odds ratio = 1.21). The most significantly associated SNPs were in intron 3 of BNC2, which encodes a zinc finger transcription factor, basonuclin-2. Expression quantitative trait loci data suggested that the associated SNPs have the potential to regulate the BNC2 transcriptional activity and that the susceptibility alleles increase BNC2 expression. We identified a functional SNP, rs10738445 in BNC2, whose susceptibility allele showed both higher binding to a transcription factor, YY1 (yin and yang 1), and higher BNC2 enhancer activity than the non-susceptibility allele. BNC2 overexpression produced body curvature in developing zebrafish in a gene-dosage-dependent manner. Our results suggest that increased BNC2 expression is implicated in the etiology of AIS.

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.

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.

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 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.

Spinal fusion as a viable treatment option for scoliosis management in Pompe disease: a postoperative 3-year follow-up.

PURPOSE: This study presents 3-year postoperative outcomes of posterior spinal correction and fusion of a patient diagnosed with late-onset Pompe disease (PD) for his progressive scoliosis. METHODS: The patient was diagnosed for PD during his infancy. Enzyme replacement therapy (ERT) was initiated at the age of 13. First office visit for his spinal deformity was at the age of 15, and 40°, 34°, 6° spinal curvatures were seen in T6-L3, T1-6, and L3-S, respectively. Reduced pulmonary function, limited gait function and atrophied limb were documented. Initial brace treatment could not control curve progression; therefore, posterior spinal correction and fusion were performed at the age of 17. RESULTS: Immediate preoperative curves of 55°, 42° and 23° were corrected to 18°, 26° and 7° in T6-L2, T1-T6 and L2-S, respectively. Spinal fusion was performed from T3 to L4. The patient exhibited an excessively low pulmonary function preoperatively with a VC, FVC, and %VC of 1.45 L, 1.36 L, and 35 %, respectively. This has been managed with only moderate reductions despite reduced pulmonary function from PD throughout the operative period and at 3 years. At the final follow-up, VC, FVC and %VC were 1.33 L, 1.12 L and 28.5 %, respectively. CONCLUSION: Posterior spinal correction and fusion adequately controlled spinal curvatures for 3 years after surgery. Additionally, pulmonary function was managed throughout the follow-up period. Despite ERT, skeletal muscle and pulmonary function can still be severely affected by PD. Spinal correction and fusion is a useful method for the management of spinal curvature and pulmonary function in patients with PD.

Reliability analysis of Cobb angle measurements of congenital scoliosis using X-ray and 3D-CT images.

PURPOSE: Therapeutic decisions for congenital scoliosis rely on Cobb angle measurements on consecutive radiographs. There have been no studies documenting the variability of measuring the Cobb angle using 3D-CT images in children with congenital scoliosis. The purpose of this study was to compare the reliability and measurement errors using X-ray images and those utilizing 3D-CT images. MATERIALS AND METHODS: The X-ray and 3D-CT images of 20 patients diagnosed with congenital scoliosis were used to assess the reliability of the digital 3D-CT images for the measurement of the Cobb angle. Thirteen observers performed the measurements, and each image was analyzed by each observer twice with a minimum interval of 1 week between measurements. The analysis of intraobserver variation was expressed as the mean absolute difference (MAD) and standard deviation (SD) between measurements and the intraclass correlation coefficient (IaCC) of the measurements. In addition, the interobserver variation was expressed as the MAD and interclass correlation coefficient (IeCC). RESULTS: The average MAD and SD was 4.5° and 3.2° by the X-ray method and 3.7° and 2.6° by the 3D-CT method. The intraobserver and interobserver intraclass ICCs were excellent in both methods (X-ray: IaCC 0.835-0.994 IeCC 0.847, 3D-CT: IaCC 0.819-0.996 IeCC 0.893). There was no significant MAD difference between X-ray and 3D-CT images in measuring each type of congenital scoliosis by each observer. CONCLUSIONS: Results of Cobb angle measurements in patients with congenital scoliosis using X-ray images in the frontal plane could be reproduced with almost the same measurement variance (3°-4° measurement error) using 3D-CT images. This suggests that X-ray images are clinically useful for assessing any type of congenital scoliosis about measuring the Cobb angle alone. However, since 3D-CT can provide more detailed images of the anterior and posterior components of malformed vertebrae, the volume of information that can be obtained by evaluating them has contributed greatly to the development of strategies for the surgical treatment of congenital scoliosis.

Medially misplaced pedicle screws in patients without neurological deficits following scoliosis surgery: to observe or to remove?

PURPOSE: This study investigated whether pedicle screws medially misplaced into the spinal canal without neurological complications should be removed or not. METHODS: A total of 86 patients with scoliosis that underwent spinal fusion using 988 pedicle screws were retrospectively reviewed after a minimum follow-up of 2 years. The inclusion criteria were: (1) patients without outstanding problems during the insertion of pedicle screws, (2) patients without neurological deficits either intraoperatively or postoperatively, and (3) patients that had all implants removed after bone union upon the request of the patient. Medial perforations were evaluated using immediate postoperative helical CT images and classified into three grades: grade 1 (0-2 mm), grade 2 (2-4 mm), and grade 3 (over 4 mm). All unexpected events were recorded at the time of removal. RESULTS: CT images obtained 2 years postoperatively exhibited neither loosening of screws nor pseudoarthrosis in all patients. CSF leakage from screw holes were recognized in 3 of 87 medially misplaced screws (3.4 %). There was no CSF leakage in grade 1 (35 screws), one CSF leakage (2.5 %) in grade 2 (40 screws), and two (16.7 %) in grade 3 (12 screws). No neurological abnormalities occurred either intraoperatively or postoperatively. CONCLUSION: This study indicated that screws medially misplaced at a distance greater than 2 mm, especially 4 mm, may be a cause of negative effects on the neural structure and should be removed during the early phase of the postoperative period, even among patients without postoperative neurological abnormalities.

Postoperative shoulder imbalance in Lenke Type 1A adolescent idiopathic scoliosis and related factors.

BACKGROUNDS: The purpose of this study was to investigate the occurrence and factors associated with postoperative shoulder imbalance (PSI) in Lenke type 1A curve. METHODS: This study included 106 patients with Lenke Type 1A curve who were followed up more than two years after posterior correction surgery. Pedicle screw (PS) constructs were used in 84 patients, and hybrid constructs in 22. The upper instrumented vertebra was rostral to the upper-end vertebra (UEV) in 70 patients, at UEV in 26, and below UEV in 10. The clavicle angle and T1 tilt angle were measured as PSI indicators, and correlations between radiographic parameters of shoulder balance and other radiographic parameters and associations between PSI and clinical parameters were investigated. For statistical analyses, paired and unpaired t-tests were used. RESULTS: The mean Cobb angles of the main and proximal thoracic curves were 54.6 ± 9.5 and 26.7 ± 7.9 degrees before surgery, 14.5 ± 7.5, and 14.9 ± 7.1 at follow-up. Clavicle angle and T1 tilt angle were -2.9 ± 2.8 and -2.6 ± 6.3 before surgery, 2.4 ± 2.8 and 4.4 ± 4.3 immediately after surgery, and 1.8 ± 2.1 and 3.4 ± 5.5 at follow-up. Twenty patients developed distal adding-on. Clavicle angle at follow-up correlated weakly but significantly with preoperative clavicle angle (r = 0.34, p = 0.001) and with the correction rates of the main thoracic curve (r = 0.34, p = 0.001); it correlated negatively with the proximal curve spontaneous correction rate (r=-0.21, p = 0.034). The clavicle angle at follow-up was significantly larger in patients with PS-only constructs (PS 2.1 degrees vs. hybrid 0.9, p = 0.02), and tended to be smaller in patients with distal adding-on (adding-on 1.1 vs. non adding-on 2.0, p = 0.09). CONCLUSIONS: PSI was more common with better correction of the main curve (using PS constructs), in patients with a larger preoperative clavicle angle, and with a larger and more rigid proximal curve. Distal adding-on may compensate for PSI.

Surgical treatment for kyphoscoliosis in Cohen syndrome.

Cohen syndrome is a very rare disease. Complication by spinal deformity has been reported, but management and surgery for spinal deformity in Cohen syndrome has not been previously described. The objective of this study was to examine the outcome of surgical treatment for kyphoscoliosis of Cohen syndrome with a literature review. The patient was a 14-year-old male with the characteristics of Cohen syndrome: truncal obesity, mental retardation, arachnodactyly, microcephalia, and a facial malformation. Scoliosis was conservatively treated with a brace at 13 years of age, but the spinal deformity rapidly progressed within a year. Plain radiographs before surgery showed scoliosis of 47 degrees (T5-T11) and 79 degrees (T11-L3), and kyphosis of 86 degrees (T7-L1). One-stage anteroposterior corrective fusion of T4-L3 was scheduled after 2-week Halo traction. Postoperative respiratory management was carefully performed because of Cohen syndrome-associated facial malformation, obesity, and reduced muscle tonus. Respiration was managed with intubation until the following day and no respiratory problems occurred. After surgery, thoracolumbar scoliosis was 28 degrees (correction rate: 65%). Kyphosis was markedly improved from 86 degrees to 20 degrees, achieving a favorable balance of the trunk. The outcome is favorable at 6.5 years after surgery. In conclusion, Cohen syndrome is often complicated by spinal deformity, particularly kyphosis, that is likely to progress even in adulthood. In our patient, spinal deformity progressed within a short period, even with brace treatment. Surgery should be required before progression to the severe spinal deformity with careful attention to general anesthesia.

Reconstructive surgery for the post-hemiepiphysiodesis residual deformity in congenital scoliosis.

Spinal hemiepiphysiodesis is a well-known surgical procedure for correcting angular deformity in which the anterior and/or posterior epiphyseal plates of several vertebrae are fused on the convex side of the curvature with the expectation of spontaneous correction through continued growth of the concave side. We report on a patient with congenital scoliosis that had problems after hemiepiphysiodesis and required a salvage, reconstructive, antero-posterior combined surgery with instrumentation and osteotomy. After hemiepiphysiodesis, a marked fusion mass and a loss of bony landmarks made osteotomy and correction with a salvage surgery extremely difficult. We suggest that confirming the fusion area after hemiepiphysiodesis and determining the appropriate osteotomy site by 3D reconstruction images are important before salvage operations.

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).

Kyphoscoliosis associated with congenital neuromuscular disease with uniform type 1 fibers.

OBJECTIVE: To report the first case of surgical treatment for severe kyphoscoliosis associated with respiratory disorder in a patient with congenital neuromuscular disease with uniform type 1 fibers (CNMDU1), including management of the possible onset of malignant hyperthermia (MH) in general anesthesia. CNMDU1 is rare among congenital neuromuscular diseases, and surgery for spinal deformity in CNMDU1 has not been described. Onset of MH in general anesthesia is a concern in this disease. METHODS: A 13-year-old female with motor retardation, suspected myopathy, and severe spinal deformity was followed at another pediatric hospital before referral to Meijo Hospital. Symptoms at the initial consultation were mild general muscular weakness and muscular atrophy. The rib hump was 60° and trunk balance was poor. The tendon reflex showed hyporeflexia, and blood tests were normal. Vital capacity was 0.69 L and forced expiratory volume percentage in 1 s was 75.5%, showing a restrictive and obstructive ventilatory defect. A plain radiograph showed severe kyphoscoliosis with thoracic scoliosis of 130° (T5-L1) and thoracic kyphosis of 110° (T2-T12) with almost no flexibility in bending or traction film. RESULTS: After preoperative halo traction for 2 months, one-stage anterior and posterior correction and fusion from T2 to L3 was conducted. MH did not occur, but recovery of respiratory function required 8 days by intubation after surgery. Postoperatively, thoracic kyphosis improved to 25° and thoracic scoliosis was 66° (correction rate: 49%). Pathological results of an intraoperative muscle biopsy from the paraspinal muscles confirmed the diagnosis of CNMDU1. At 6 years after surgery, the patient has no problems in daily life and no respiratory difficulty. CONCLUSION: Spinal deformity in CNMDU1 has a risk of severe progression, which makes early diagnosis by biopsy important. The surgery may be recommended before severe progression of spinal deformity and respiratory disorder. Perioperative MH is a concern, but can be managed by appropriate procedures.

Increase in spinal longitudinal length by correction surgery for adolescent idiopathic scoliosis.

PURPOSE: One of the downsides of spinal correction surgery for adolescent idiopathic scoliosis (AIS) is the cessation of spinal longitudinal growth within the fused levels in growing children. However, the surgery itself has the potential to increase spinal longitudinal length by correcting the curvature. The purpose of this study was to evaluate the correlation between curve correction and increased spinal longitudinal length by corrective surgery for AIS. METHODS: This study included 208 consecutive patients (14 male, 194 female) with AIS who underwent posterior or anterior correction and fusion surgeries. Mean age at the time of surgery was 15.7 ± 3.3 years (range 10-20 years). Patients with hyperkyphosis of more than 40° were excluded. All patients had main curves in the thoracic spine (Lenke type 1 or 2). Forty-three patients underwent anterior spinal correction and fusion (ASF) and 164 underwent posterior spinal correction and fusion (PSF). The mean preoperative height was 154.7 ± 6.9 cm (range 133-173 cm). Pre and postoperative PA standing X-ray films were used to measure the Cobb angle and spinal length between the end vertebrae of the main thoracic curve, and between T1 and L5. The patients were divided into ASF and PSF groups, within which correlations between the Cobb angle correction and spinal length increase were evaluated. RESULTS: In the ASF group, the mean preoperative Cobb angle of the main thoracic curve was 54.9 ± 8.3° (range 41-83°) and it was corrected to 19.7 ± 9.5° (range 0-47°) with a mean correction of 35.2 ± 11.1° (range 10-74°) after surgery. The mean increase in the length of the main thoracic curve was 1.5 ± 4.6 mm (range -8 to 13 mm), and the mean increase in T1-L5 length was 16.6 ± 7.7 mm (range -3 to 51 mm). Significant correlation between the correction of the Cobb angle and increase in T1-L5 length was observed, with a correlation coefficient of 0.44. In the PSF group, the mean preoperative Cobb angle of the main thoracic curve was 58.8 ± 11.6° (range 36-107°) and it was corrected to 17.1 ± 7.6° (range 10-49°), with a mean correction of 41.7 ± 10.2° (range 21-73°) after surgery. The mean increase in the length of the main thoracic curve was 14.0 ± 5.2 mm (range 0-42 mm), and the mean increase in T1-L5 length was 32.4 ± 10.8 mm (10-61 mm). Correlation between the correction of the Cobb angle and increase in T1-L5 length was high, with a correlation coefficient of 0.64. The increase in T1-L5 length could be calculated by the following formula based on linear regression analysis: increase in T1-L5 length (mm) = correction of the Cobb angle (º) × 0.77. CONCLUSION: Spinal longitudinal length was significantly increased after surgery in both the ASF and PSF groups. Correction of the Cobb angle and increase in T1-L5 length were highly correlated with each other, especially in the PSF group.