Risk Factors for Proximal Junctional Fracture Following Fusion Surgery for Osteoporotic Vertebral Collapse with Delayed Neurological Deficits: A Retrospective Cohort Study of 403 Patients.

INTRODUCTION: Approximately 3% of osteoporotic vertebral fractures develop osteoporotic vertebral collapse (OVC) with neurological deficits, and such patients are recommended to be treated surgically. However, a proximal junctional fracture (PJFr) following surgery for OVC can be a serious concern. Therefore, the aim of this study is to identify the incidence and risk factors of PJFr following fusion surgery for OVC. METHODS: This study retrospectively analyzed registry data collected from facilities belonging to the Japan Association of Spine Surgeons with Ambition (JASA) in 2016. We retrospectively analyzed 403 patients who suffered neurological deficits due to OVC below T10 and underwent corrective surgery; only those followed up for　≥2 years were included. Potential risk factors related to the PJFr and their cut-off values were calculated using multivariate logistic regression analysis and receiver operating characteristic (ROC) analysis. RESULTS: Sixty-three patients (15.6%) suffered PJFr during the follow-up (mean 45.7 months). In multivariate analysis, the grade of osteoporosis (grade 2, 3: adjusted odds ratio (aOR) 2.92; p=0.001) and lower instrumented vertebra (LIV) level (sacrum: aOR 6.75; p=0.003) were independent factors. ROC analysis demonstrated that lumbar bone mineral density (BMD) was a predictive factor (area under curve: 0.72, p=0.035) with optimal cut-off value of 0.61 g/cm2 (sensitivity, 76.5%; specificity, 58.3%), but that of the hip was not (p=0.228). CONCLUSIONS: PJFr was found in 16% cases within 4 years after surgery; independent risk factors were severe osteoporosis and extended fusion to the sacrum. The lumbar BMD with cut-off value 0.61 g/cm2 may potentially predict PJFr. Our findings can help surgeons select perioperative adjuvant therapy, as well as a surgical strategy to prevent PJFr following surgery.

Analysis of skeletal muscle mass in women over 40 with degenerative lumbar scoliosis.

PURPOSE: We investigated the involvement of sarcopenia in middle-aged and elderly women with degenerative lumbar scoliosis (DLS). METHODS: A total of 971 women (mean age 70.4 years) were included in our study. These included 87 cases of DLS (mean 73.8 years) and 884 controls (69.8). Lumbar and femur BMD was measured for all participants using dual-energy X-ray absorptiometry. We used a bioelectrical impedance analyzer to analyze body composition, including appendicular skeletal muscle mass index (SMI; appendicular lean mass (kg)/(height (m))2. We determined bone density and skeletal muscle mass in both groups and determined the prevalence of sarcopenia. We examined the correlation between bone density and appendicular muscle mass in both groups. We also examined factors related to scoliosis using logistic regression analysis. RESULTS: The DLS group showed significantly higher lumbar BMD, lower femur BMD, lower lean mass arm, and lower lean mass leg, and lower lean mass trunk (p < 0.05). Sarcopenia prevalence (SMI < 5.75) was 59.8% in DLS subjects and 42.8% in controls, revealing a high prevalence in DLS (p < 0.05). In both groups, lumbar and femur BMD were positively correlated with appendicular muscle mass. By logistic regression analysis, trunk muscle mass was detected as a risk factor for DLS independent of age (p < 0.05). CONCLUSIONS: In middle-aged and elderly women, prevalence of sarcopenia was 59.8% in DLS cases and 42.8% in controls, which revealed a high prevalence in DLS. A decrease in trunk muscle was a significant risk factor for DLS that was independent of age. These slides can be retrieved under Electronic Supplementary Material.