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).

Surgical Predictors for Prevention of Postoperative Shoulder Imbalance in Lenke Type 2A Adolescent Idiopathic Scoliosis.

STUDY DESIGN: Multicenter, retrospective cohort study. OBJECTIVE: The aim of this study was to investigate the occurrence and surgical predictors of postoperative shoulder imbalance (PSI) in Lenke type 2A adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA: Although several studies have investigated the factors influencing PSI in Lenke type 2 curves, no studies have analyzed PSI-related factors considering upper instrumented vertebra (UIV) and lumbar modifier type simultaneously. METHODS: Patients with Lenke Type 2A AIS treated by spinal fusion were retrospectively identified and their data were extracted from six spine centers in Japan. Inclusion criteria were age between 10 and 20 years at surgery, UIV = T2, major curve 40° to 90°, and follow-up for 24 to 30 months after surgery. We analyzed patient characteristics, surgical characteristics, and preoperative and immediate-postoperative radiographic parameters. We defined patients with lower instrumented vertebra (LIV) equal or proximal to the last touching vertebra (LTV) as selective thoracic fusion (STF-LTV) and patients with LIV distal to the LTV as non-STF-LTV. t Tests, Mann-Whitney U test, χ2 tests, Fisher exact tests, and multivariate logistic regression were used for statistical analyses. RESULTS: Among the 99 consecutive patients with a mean follow-up of 25.6 months, PSI was seen in 27 (27.3%) patients immediately after and in 17 (17.2%) patients at 24 to 30 months. The univariate analysis revealed that the significant risk factors of PSI were preoperative radiographical shoulder height, non-STF-LTV, and high main thoracic curve (MTC) correction (immediate-postoperative MTC correction rate: ≥70%), with PSI incidence of 40.0%. The multivariate logistic regression analysis indicated that interaction term of non-STF-LTV and high MTC correction was an independent risk factor for PSI (non-STF-LTV and high MTC correction, odds ratio: 5.167, 95% confidence interval: 1.470-18.159, P = 0.010). CONCLUSION: To prevent PSI in Lenke Type 2A AIS patients, surgeons should avoid the combination of non-STF-LTV and high MTC correction in those surgeries with UIV as T2.Level of Evidence: 4.

Scoliosis in Shprintzen-Goldberg Syndrome.

We report a case of scoliosis in a 12-year-old girl with Shprintzen-Goldberg syndrome. She was diagnosed with Shprintzen-Goldberg syndrome at birth. She was hospitalized for a surgical treatment because scoliosis gradually progressed. Preoperative X-ray confirmed 80° symptomatic scoliosis in T10-L5. Posterior correction and fusion were performed, and postoperative X-ray showed a correction to 43°in T10-L5. Limited subcutaneous tissues and fragile bones must be considered when selecting the appropriate surgical method. Accurate placement of a screw into thin pedicle is essential to obtain sufficient correction and fusion. The use of a navigation system is recommended.

Novel Hump Measurement System With a 3D Camera for Early Diagnosis of Patients With Adolescent Idiopathic Scoliosis: A Study of Accuracy and Reliability.

Background Adolescent idiopathic scoliosis (AIS) is a potentially progressive deformity, and early detection is crucial for timely intervention. However, the methods and criteria justifying screening for pediatric scoliosis remain controversial. We have, therefore, independently developed a Digital Moiré (DM) as a tool for scoliosis screening. The purpose of this study was to assess the usefulness of DM for scoliosis screening. Methods From March 2016 to March 2017, 126 patients (18 boys, 108 girls, mean age: 13.2 ± 2.2 years) with AIS underwent radiographic imaging of their whole spine. We tested the accuracy and reliability of DM by categorizing the examination results as Class 0 (no abnormality), Class 1 (return visit in one year), and Class 2 (further examination needed) and determined the distribution of the population by Cobb angle. The intra/inter-rater reliability and receiver operating characteristic (ROC) analyses were used to categorize the patients with positive findings into Class 1 or 2. Results Regarding the population distribution per Cobb angle in each of the distributions, 11 patients (8.7%) were Class 0, of which nine and two patients had Cobb angle ≤ 10 ° and > 10 °, respectively. There were 20 (15.9% ) Class 1 cases, of which 17 and three had Cobb angle ≤ 10 ° and > 10 °, respectively. Of the 95 (75.4%) Class 2 cases, five and 90 had a Cobb angle of ≤ 10 ° and > 10 °, respectively. The receiver operating characteristic (ROC) analysis of patients with positive findings showed that the area under the curve (AUC), sensitivity, specificity, and false-positive rate were 0.76, 0.98, 0.53, and 0.47, respectively, when predicting Cobb angle > 10°. Intra-rater and inter-rater reliability were 0.73 and 0.70, respectively. Conclusions This study demonstrated the usefulness of DM for determining whether a child with AIS requires a follow-up observation such as radiograph. Our findings suggest that the novel DM shows high accuracy and reliability for scoliosis screening.

Relationship between characteristics of spinopelvic alignment and quality of life in Japanese patients with ankylosing spondylitis: a cross-sectional study.

BACKGROUND: Studies on characteristic spinal deformities in Japanese patients with ankylosing spondylitis (AS) and data demonstrating a relationship between health-related quality of life (HRQOL) and spinopelvic alignment in these patients are lacking. METHODS: In this cross-sectional study, 50 patients with AS and without a surgical history, vertebral body fracture, or scoliosis as well as 30 control patients with degenerative lumbar kyphoscoliosis (DLKS) were included. Data collected included patient sex, age, spinopelvic parameters on sagittal full-spine standing radiographs, and HRQOL questionnaire responses. Student's t-test was used to compare the characteristics of spinopelvic parameters between the groups. A multiple regression analysis was performed to analyze correlations between spinopelvic parameters and HRQOL in the AS group. RESULTS: Global kyphosis (GK; T1-12 angle) was significantly greater in the AS group than in the DLKS group (P < 0.001), whereas the pelvic tilt (PT; posterior PT angle) was smaller in the AS group (P = 0.006). Radiographic parameters correlated with HRQOL in the AS group. Multiple regression analysis identified the sagittal vertical axis (SVA) and sacral slope (SS) as factors influencing the SRS-22 total score and SVA and GK as factors influencing Japanese Orthopaedic Association Back Pain Evaluation Questionnaire mental health (subdomain). CONCLUSIONS: Patients with AS did not use lumbar lordosis or posterior PT to compensate for their large thoracic kyphosis due to spinopelvic ankylosis. These patients showed a unique compensation pattern. The correlation/regression analysis revealed a correlation between radiographic parameters and HRQOL in patients with AS, with particular importance of SVA, SS, and GK for clinical results in AS.

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.

Bi-allelic loss of function variants of TBX6 causes a spectrum of malformation of spine and rib including congenital scoliosis and spondylocostal dysostosis.

BACKGROUND: Congenital scoliosis (CS) is a common vertebral malformation. Spondylocostal dysostosis (SCD) is a rare skeletal dysplasia characterised by multiple vertebral malformations and rib anomalies. In a previous study, a compound heterozygosity for a null mutation and a risk haplotype composed by three single-nucleotide polymorphisms in TBX6 have been reported as a disease-causing model of CS. Another study identified bi-allelic missense variants in a SCD patient. The purpose of our study is to identify TBX6 variants in CS and SCD and examine their pathogenicity. METHODS: We recruited 200 patients with CS or SCD and investigated TBX6 variants. We evaluated the pathogenicity of the variants by in silico prediction and in vitro experiments. RESULTS: We identified five 16p11.2 deletions, one splice-site variant and five missense variants in 10 patients. In vitro functional assays for missense variants identified in the previous and present studies demonstrated that most of the variants caused abnormal localisation of TBX6 proteins. We confirmed mislocalisation of TBX6 proteins in presomitic mesoderm cells induced from SCD patient-derived iPS cells. In induced cells, we found decreased mRNA expressions of TBX6 and its downstream genes were involved in somite formation. All CS patients with missense variants had the risk haplotype in the opposite allele, while a SCD patient with bi-allelic missense variants did not have the haplotype. CONCLUSIONS: Our study suggests that bi-allelic loss of function variants of TBX6 cause a spectrum of phenotypes including CS and SCD, depending on the severity of the loss of TBX6 function.

Screening of known disease genes in congenital scoliosis.

BACKGROUND: Congenital scoliosis (CS) is defined as a lateral curvature of the spine due to the vertebral malformations and has an incidence of 0.5-1/1,000 births. We previously examined TBX6 in Japanese CS patients and revealed that approximately 10% of CS was caused by TBX6 mutations. However, the genetic cause of remaining CS is unknown. METHODS: We recruited 78 CS patients without TBX6 mutations and major comorbidities, and investigated the genes previously reported to be associated with CS and congenital vertebral malformations by whole-exome sequencing. RESULTS: We identified the compound heterozygous missense variants in LFNG in one patient. No likely disease-causing variants were identified in other patients, however. LFNG encodes a GlcNAc-transferase. The LFNG variants showed loss of their enzyme function. CONCLUSIONS: A LFNG mutation is reported in a case of spondylocostal dysostosis (SCD), a skeletal dysplasia with severe malformations of vertebra and rib. The CS patient with LFNG mutations had multiple vertebral malformations including hemivertebrae, butterfly vertebrae, and block vertebrae, and rib malformations. LFNG mutations may cause a spectrum of phenotypes including CS and SCD. The current list of known disease genes could explain only a small fraction of genetic cause of CS.

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.

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.

Surgical treatment for lumbar hyperlordosis after resection of a spinal lipoma associated with spina bifida: A case report.

RATIONALE: A hyperlordosis deformity of the lumbar spine is relatively rare, and surgical treatment has not been comprehensively addressed. In this case report, we describe the clinical presentation, surgical treatment, and medium-term follow-up of a patient presenting with a progressive lumbar hyperlordosis deformity after resection of a spinal lipoma associated with spina bifida. PATIENT CONCERNS: The patient was a 20-year-old woman presenting with a progressive hyperlordosis deformity of the lumbar spine associated with significant back pain (visual analog pain score of 89/100 mm), but with no neurological symptoms. DIAGNOSES: The lumbar lordosis (LL), measured on standing lateral view radiographs, was 114°, with a sagittal vertical axis (SVA) of -100 mm. The patient had undergone excision of a lipoma, associated with spina bifida of the lumbar spine, at 7 months of age.She was first evaluated at our hospital at 18 years of age for progressive spinal deformity and lumbago. INTERVENTIONS: An in situ fusion, from T5 to S1, using pedicle screws with bone graft obtained from the iliac crest, was performed. OUTCOMES: Postoperatively, the LL decreased to 93°, and the SVA decreased to -50 mm. The decision to not correct the hyperlordosis deformity fully was intentional. Seven years and 1 month postsurgery, the patient had no limitations in standing and walking and reported a pain score of 8/100 mm; there was no evidence of a loss of correction. LESSONS: Lumbar hyperlordosis after resection of a spinal lipoma associated with spina bifida is rare. Posterior fixation provided an effective treatment in this case. As the lumbar hyperlordosis deformity is often high, correction can be difficult. In this case, although the correction and fusion were performed in situ, there was no progression of either the deformity or the lumbago. Early detection remains an essential component of effective treatment, allowing correction when the spinal deformity is easily reversible.

Physical Activities and Lifestyle Factors Related to Adolescent Idiopathic Scoliosis.

BACKGROUND: In addition to genetic factors, environmental and lifestyle factors are thought to play an important role in the onset of adolescent idiopathic scoliosis (AIS). This cross-sectional study was conducted to explore lifestyle factors related to AIS. METHODS: This study included 2,759 Japanese female junior high school students who planned a secondary screening after an initial moiré topography screening indicated possible scoliosis. The students and their mothers, or guardians, were asked to fill out a questionnaire consisting of 38 questions about demographic factors, lifestyle-related factors, social factors, household environment, participation in sports, health status, and factors related to the mother's pregnancy and delivery. The questionnaire was completed by 2,747 students (a 99.6% response rate). After excluding students with heart disease, neurological disease, or a congenital vertebral anomaly, 2,600 students were eligible for assessment. After undergoing a secondary screening with standing radiographs of the spine, students were assigned to the normal (control) group if radiographs showed a curve of <15° or to the scoliosis group if they had a curve of ≥15°. The odds ratios (ORs) for AIS in relation to the possible risk or preventive factors were estimated by logistic regression analyses. RESULTS: No lifestyle-related factor was significantly associated with AIS. However, AIS was associated with classical ballet training (OR, 1.38; 95% confidence interval [CI], 1.09 to 1.75); the odds of AIS developing increased as the child's frequency of training, number of years of experience, and duration of training in ballet increased. The OR for AIS was 1.5 times higher for participants whose mothers had scoliosis. AIS was also associated with a low body mass index (BMI). These associations remained even after mutual adjustment was performed. CONCLUSIONS: No association was found between AIS and lifestyle-related factors. However, classical ballet training, a family history of scoliosis, and low BMI may be associated with AIS. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Spontaneous improvement of cervical kyphosis in eosinophilic granuloma: a case report.

We describe the case of a spontaneous improvement of the cervical kyphosis in eosinophilic granuloma with long-term follow-up. A collapse of the C5 vertebral body was confirmed by cervical spine radiography and computed tomography. The patient wore a sterno-occipitalmandibular immobilizer brace for 6 months, and remodeling of the vertebral body was confirmed 18 months after onset. Seven years have passed since the onset of symptoms, and the patient's cervical spine has maintained normal alignment. Management of eosinophilic granuloma of the pediatric cervical spine is still controversial. Conservative treatment suffices as adequate management of cervical eosinophilic granuloma, even with kyphotic deformity.

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.

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.

Association of postoperative shoulder balance with adding-on in Lenke Type II adolescent idiopathic scoliosis.

STUDY DESIGN: A retrospective, multicenter study. OBJECTIVE: To investigate the relationship between postoperative shoulder balance and adding-on in Lenke type 2 adolescent idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: Postoperative shoulder imbalance (PSI) and adding-on are the main postoperative complications occurring at the proximal to upper instrumented vertebra and the distal to the lower instrumental vertebra (LIV), respectively. Inadequate selection of LIV in the selective thoracic fusion surgery may result in postoperative distal adding-on. It remains unclear whether postoperative shoulder balance is associated with postoperative adding-on. METHODS: Preoperative, postoperative, and 2-year follow-up radiographs of 142 consecutive patients with Lenke type 2 curves who underwent posterior-fusion surgery were analyzed. The patients were grouped into PSI positive and negative at follow-up. Radiographical and categorical factors between patients with and without PSI were compared. The relationship between the radiographical shoulder height and the parameters of adding-on were analyzed. RESULTS: PSI occurred in 23 patients (16.2%) and distal adding-on was recognized in 20 patients (14.1%) at final follow-up. The occurrence of adding-on was significantly lower in the shoulder imbalance group at follow-up (P < 0.01). There was no shoulder imbalance occurring in the patients with distal adding-on at final follow-up (P < 0.01). Correlation analysis showed that the radiographical shoulder height was positively correlated with the change in the angulation of the first disc below LIV (r = 0.228, P ≤ 0.01) and negatively correlated with the deviation change of the LIV+1 at follow-up (r = -0.254, P ≤ 0.01). CONCLUSION: The postoperative shoulder balance and postoperative distal adding-on were weakly but significantly associated with each other, and both shoulder imbalance and adding-on need to be prevented in Lenke type 2 curves.

Promotion of normal healing of bone defects under estrogen deficiency by implantation of beta-tricalcium phosphate composed of rod-shaped particles.

We compared the healing of bone defects in ovariectomized rats implanted with beta-tricalcium phosphate (b-TCP)composed of rod-shaped particles, which were prepared using the applied hydrothermal method (HTCP), and that of bone defects implanted with conventional b-TCP composed of globular-shaped particles (CTCP), which were prepared by normal sintering. Eight week-old female Wistar rats were ovariectomized, and 2 weeks after the operation, 0.5- to 0.6-mm diameter spherical granules of each ceramic were implanted in a bone defect created in the distal end of the femur. Four, 8, and 12 weeks after implantation, the amount of newly formed bone implanted with HTCP was significantly larger than that implanted with CTCP and was equivalent to that in non-ovariectomized sham-operated rats. Without implantation, spontaneous repair of the trabecular bone was barely observed. The physiological structure of the trabecular network was maintained in the region implanted with HTCP, but that in the region implanted with CTCP was severely destroyed. Gene expression microarray analysis revealed that the expression of genes involved in interferon signaling pathways was upregulated in osteoclasts cultured on HTCP compared with that cultured on CTCP. Our results suggest that the microstructure of b-TCP affected the biological behavior of osteoclasts and regulated local bone metabolism.

Selection of lower instrumented vertebra in treating Lenke type 2A adolescent idiopathic scoliosis.

STUDY DESIGN: A retrospective, observational, and multicenter study. OBJECTIVE: To identify the ideal lower instrumented vertebra (LIV) to prevent distal adding-on after surgical correction of Lenke type 2A curve. SUMMARY OF BACKGROUND DATA: LIV level may affect the risk of postsurgical adding-on. The choice of the last touching vertebra (LTV)-the most caudal vertebra of the main thoracic curve that touches the central sacral vertical line when standing-as an appropriate LIV has been validated for Lenke type 1A but not type 2A curve. METHODS: Radiographs obtained before, immediately after, and 2 years after surgery were evaluated for 116 consecutive patients who underwent posterior thoracic fusion surgery for Lenke type 2A curve. The LIV was proximal to the LTV in 18 patients (PLTV), distal in 43 (DLTV), and at the LTV in 55 (ALTV). Significant independent factors associated with adding-on were analyzed first by univariate analysis, and then by stepwise logistic regression analysis. RESULTS: Distal adding-on was present in 16 patients (13.8%) at follow-up: 9 PLTV (50.0%), 3 DLTV (7.0%), and 4 ALTV (7.3%). Adding-on was significantly more common in the PLTV group. One PLTV-group patient required revision surgery to treat adding-on. Univariate analysis identified the following significant factors associated with adding-on: the T2-T5 kyphosis angle and shoulder height before, immediately after, and 2 years after surgery; the lumbar Cobb angle at the 2-year follow-up; the 2-year postoperative lumbar curve correction rate; and the difference between the LIV and the end vertebra, neutral vertebra, and LTV levels. Significant independent risk factors identified by stepwise logistic regression analysis included the clavicle angle at follow-up, the correction rate of the lumbar curve immediately after surgery, and the difference between the LIV and LTV levels. CONCLUSION: A LIV at or distal to the LTV may prevent postoperative adding-on in Lenke type 2A curve. LEVEL OF EVIDENCE: 3.

A case of paraparesis with thoracic ossification of the posterior longitudinal ligament and the ligamentum flavum induced by falling down on the abdomen.

AIM: To describe an educational case. METHODS: Case report. RESULTS: A 71-year-old female was transported to our emergency department with complaints of lower abdominal pain and gate disturbance after falling down on her abdomen. She had lower abdominal painful paresthesia in the dermatome from the twelfth thoracic to the first lumbar level without signs of peritoneal stimulation. Paraparesis and dysesthesia of the lower extremities was predominant on the left side. Abdominal computed tomography revealed severe thoracic ossification of the posterior longitudinal ligament and the ligamentum flavum at the thoracic level 10/11. Laminectomy and spinal fusion with rods resulted in recovery of the patient's symptoms. CONCLUSION: Physician should pay attention to thoracic spinal cord injury induced by hyperextensive stress on the spine, even in cases of minor trauma, among patients with preexisting bony pathologies at the thoracolumbar level.