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Extreme lateral interbody fusion (XLIF) is often used with posterior spinal fixation (PSF) to treat adult spinal deformity (ASD). However, the amount of intraoperative blood loss (IBL) reported for XLIF may underestimate the total blood loss (TBL). The objective of this study was to determine the total perioperative blood loss in XLIF for ASD.We assessed 30 consecutive ASD patients with Schwab-SRS type L (mean age: 68.7 ± 8.2 years; mean follow-up 2.0 ± 1.3 years) who were treated by multilevel XLIF (mean, 2.5 ± 0.6 levels) followed by PSF after 3-5 days. We calculated the TBL after XLIF by the Gross equation, by hemoglobin (Hb) balance, and by the Orthopedic Surgery Transfusion Hemoglobin European Overview (OSTHEO) formula. We defined hidden blood loss (HBL) as the difference between the TBL and IBL. Pearson correlation, Spearman correlation, and multiple logistic regression analysis were performed to investigate the risk factors related to HBL.Post-XLIF blood tests showed a significant decrease in the Hb (from 11.8 ± 1.1 mg/dl to 10.6 ± 1.1 mg/dl) and hematocrit (from 36.0 ± 3.2% to 32.5 ± 3.2%). Although the mean IBL was relatively small (33 ± 52 mL), we calculated the TBL as 291 ± 171 mL (Gross equation) and the HBL as 258 ± 168 mL by Gross equation, which was 8 times greater than the IBL on average. There was no difference in the results obtained using the three methods. Multiple logistic regression analysis indicated preoperative lumber lordosis was the risk factor of high HBL (Odds ratio = 1.085, 95%CI: 1.006-1.170, p = 0.035).The HBL in XLIF was 8 times greater than the IBL. During the perioperative course of correction and fusion surgery for ASD with XLIF, surgeons need to pay attention not to underestimate the TBL.

Study Design: This is a retrospective study.Purpose: This study aims to evaluate the risk factor associated with pseudoarthrosis after placement of lateral interbody fusion (LIF) cages for adult spinal deformity (ASD) treatment. Overview of Literature: LIF technique is widely used for ASD correction. Furthermore, pseudoarthrosis is a major complication of fusion surgery required for revision surgery.Methods: This study included 42 patients with ASD (two men and 40 women; 112 segments; mean, 68.5±8.4 years; and mean follow-up, 31.6±17.0 months) who underwent LIF and posterior correction surgery. The concave slot of the LIF cage was filled with an autologous iliac crest bone graft (IBG), and the convex slot with a porous hydroxyapatite/collagen (HAp/Col) composite was soaked with bone marrow aspirate. Endplate injury, the gap between vertebral endplate and cage in the coronal or sagittal plane, and fusion status were evaluated using computed tomography multiplanar reconstruction at 12 months after surgery. Moreover, the associated risk factors for pseudoarthrosis were analyzed.Results: Fusion at LIF segments were observed in 71.4% segments at 12 months after surgery. Fusion on the concave slot (autologous IBG side), convex slot (porous HAp/Col composite side), and both concave and convex slots were observed in 66.1%, 37.5%, and 36.6% of patients, respectively. Moreover, pseudoarthrosis was observed in 28.6% at 12 months after surgery. Consequently, logistic regression analysis of the fusion at the LIF segment revealed that the gap between the LIF cage and endplate in the coronal plane (p=0.030; odds ratio, 0.183; 95% confidence interval, 0.030–0.183) was significantly associated with pseudoarthrosis at the LIF segments.Conclusions: ASD surgery fusion rate using LIF cages was 71.4% at 12 months after surgery. The fusion rate was higher on the concave slot filled with autologous IBG than on the convex slot filled with a porous HAp/Col composite. The gap in the coronal plane was a risk factor for pseudoarthrosis at the LIF segment.

Background The K-line in the neck-flexed position (FK-line) on radiography reflects dynamic factors and cervical alignment. Although the FK-line has been reported to affect the neurological recovery after muscle-preserving selective laminectomy for cervical spondylotic myelopathy (CSM), its influence on surgical outcomes after expansive open-door laminoplasty (ELAP) has not been investigated. Methods We reviewed the surgical outcomes in 81 patients with multilevel CSM who underwent C4–C6 ELAP combined with C3 and C7 partial laminectomy using a laminoplasty plate and were followed up for at least 2 years. We defined the K-line (−) as some portion of a bony spur or the vertebral body crossing the FK-line, whereas the FK-line (+) was defined as that never crossing the FK-line. Patients were divided into the FK-line (+) (n = 61) and FK-line (−) groups (n = 20), and the surgical outcomes were compared between the groups. A multivariate analysis was performed to identify the factors that influenced the neurological outcomes. Results The FK-line (−) group had a smaller C2–C7 angle, smaller C7 slope, greater postoperative increase in the C2–C7 sagittal vertical axis, greater kyphosis in cervical flexion and less lordosis in cervical extension, and higher incidence of postoperative residual spinal cord compression. The preoperative-to-postoperative changes in the Japanese Orthopedic Association (JOA) score and JOA score recovery rate (RR) were lower in the FK-line (−) group. The multiple linear regression analysis revealed that the K-line (−) (β = −0.327, P = 0.011) and high signal intensity (SI) changes on T2-weighted imaging (WI) combined with the low SI changes on T1-WI in the spinal cord (β = −0.320, P = 0.013) negatively affected the JOA score RR. Conclusions The FK-line can be used for patients with CSM as a simple indicator of neurological outcomes after ELAP.

Background Patients with diffuse idiopathic skeletal hyperostosis (DISH) are susceptible to spinal column injuries with neurological deterioration. Previous studies indicated that the prevalence of diabetes mellitus (DM) in patients with DISH was higher than that in patients without DISH. This study investigates the impact of DM on surgical outcomes for spinal fractures in patients with DISH. Methods We retrospectively evaluated 177 spinal fractures in patients with DISH (132 men and 45 women; mean age, 75 ± 10 years) who underwent surgery from a multicenter database. The subjects were classified into two groups according to the presence of DM. Perioperative complications, neurological status by Frankel grade, mortality rate, and status of surgical site infection (SSI) were compared between the two groups. Results DM was present in 28.2% (50/177) of the patients. The proportion of men was significantly higher in the DM group (DM group: 86.0% vs. non-DM group: 70.1%) (p = 0.03). The overall complication rate was 22.0% in the DM group and 19.7% in the non-DM group (p = 0.60). Poisson regression model revealed that SSI was significantly associated with DM (DM group: 10.0% vs. non-DM group: 2.4%, Relative risk: 4.5) (p = 0.048). Change in neurological status, mortality rate, instrumentation failure, and nonunion were similar between both groups. HbA1c and fasting blood glucose level (SSI group: 7.2% ± 1.2%, 201 ± 67 mg/dL vs. non-SSI group: 6.6% ± 1.1%, 167 ± 47 mg/dL) tended to be higher in patients with SSI; however, there was no significant difference. Conclusions In spinal fracture in patients with DISH, although DM was an associated factor for SSI with a relative risk of 4.5, DM did not negatively impact neurological recovery. Perioperative glycemic control may be useful for preventing SSI because fasting blood glucose level was high in patients with SSI.

Patients with DISH are susceptible to spinal fractures and subsequent neurological impairment, including after minor trauma. However, DISH is often asymptomatic and fractures may have minimal symptoms, which may lead to delayed diagnosis. The purpose of this study was to identify risk factors for delayed diagnosis of spinal fractures in patients with diffuse idiopathic skeletal hyperostosis (DISH).The subjects were 285 patients with DISH surgically treated at 18 medical centers from 2005 to 2015. Cause of injury, imaging findings, neurological status at the times of injury and first hospital examination, and the time from injury to diagnosis were recorded. A delayed diagnosis was defined as that made24 h after injury.Main causes of injury were minor trauma due to a fall from a standing or sitting position (51%) and high-energy trauma due to a fall from a high place (29%) or a traffic accident (12%). Delayed diagnosis occurred in 115 patients (40%; 35 females, 80 males; mean age 76.0 ± 10.4 years), while 170 (60%; 29 females, 141 males; mean age 74.6 ± 12.8 years) had early diagnosis. Delayed group had a significantly higher rate of minor trauma (n = 73, 63% vs. n = 73, 43%), significantly more Frankel grade E (intact neurological status) cases at the time of injury (n = 79, 69% vs. n = 73, 43%), and greater deterioration of Frankel grade from injury to diagnosis (34% vs. 8%, p 0.01). In multivariate analysis, a minor trauma fall (OR 2.08; P 0.05) and Frankel grade E at the time of injury (OR 2.29; P 0.01) were significantly associated with delayed diagnosis.In patients with DISH, it is important to keep in mind the possibility of spinal fracture, even in a situation in which patient sustained only minor trauma and shows no neurological deficit. This is because delayed diagnosis of spinal fracture can cause subsequent neurological deterioration.

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).

Chemonucleolysis with condoliase, which degrades chondroitin sulfate, could be a new, minimally invasive therapeutic option for patients with lumbar disc herniation (LDH). The purpose of this study was to analyze prognostic factors for clinical outcomes in LDH patients subjected to chemonucleolysis with condoliase.Inclusion criteria for this procedure were 1) 18-70 years of age; 2) unilateral leg pain and positive straight leg raise (SLR) (70°) or femoral nerve stretching test; 3) subligamentous extrusion verified on magnetic resonance imaging; 4) neurological symptoms consistent with a compressed nerve root on magnetic resonance imaging (MRI) images; and 5) minimum six months of follow-up. In total, 82 patients (55 men, 27 women; mean age, 47.2 ± 15.5 years; mean follow-up, 9.1 ± 3.0 months) who underwent chemonucleolysis with condoliase for painful LDH were included. An improvement of 50% or more in the Visual analogue scale (VAS) of leg pain was classified as effective.Seventy patients (85.4%) were classified into the effective (E) group and 12 patients (14.6%) into the less-effective (L) group. Surgical treatment was required in four patients. No severe adverse complications were reported; 41.3% of the patients developed disc degeneration of Pfirrmann grade 1 or more at the injected disc level. Univariate analysis revealed that young age (p = 0.036), without history of epidural or nerve root block (p = 0.024), and injection into the central portion of the intervertebral disc (p = 0.014) were significantly associated with clinical effectiveness. A logistic regression analysis revealed that injection into the central portion of the intervertebral disc (p = 0.049; odds ratio, 4.913; 95% confidence interval, 1.006-26.204) was significantly associated with clinical effectiveness.Chemonucleolysis with condoliase is a safe and effective treatment for painful LDH; 85.4% of the patients showed improvement after the treatment without severe adverse events. To obtain the best outcome, condoliase should be injected into the center of the intervertebral disc.

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).

Age-related changes in the posterior extensor muscles of the cervical and lumbar spine have been reported in some studies; however, longitudinal changes in the thoracic spine of healthy subjects are rarely reported. Therefore, this study aimed to evaluate changes in the cross-sectional areas (CSAs) of posterior extensor muscles in the thoracic spine over 10 years and identify related factors. The subjects of this study were 85 volunteers (mean age: 44.7 ± 11.5) and the average follow-up period was about 10 years. The CSAs of the transversospinalis muscles, erector spinae muscles, and total CSAs of the extensor muscles from T1/2 to T11/12 were measured on magnetic resonance imaging. The extent of muscle fat infiltration was assessed by the signal intensity (luminance) of the extensor muscles’ total cross-section compared to a section of pure muscle. We applied a Poisson regression model, which is included in the generalized linear model, and first examined the univariate (crude) association between each relevant factor (age, sex, body mass index, lifestyle, back pain, neck pain, neck stiffness, and intervertebral disc degeneration) and CSA changes. Then, we constructed a multivariate model, which included age, sex, and related factors in the univariate analysis. The mean CSAs of the transversospinalis muscles, erector spinae muscles, and total CSAs of the extensor muscles significantly increased over 10 years. Exercise habit was associated with increased CSAs of the erector spinae muscles and the total area of the extensor muscles. The cross-section mean luminance significantly increased from baseline, indicating a significant increase of fat infiltration in the posterior extensor muscles. Progression of disc degeneration was inversely associated with increased fat infiltration in the total extensor muscles.

Objective Diffuse idiopathic skeletal hyperostosis (DISH) causes spinal ankylosis, which can result in patients suffering specific spinal fractures that lead to a reduction in the activities of daily life in older patients. Currently, DISH is associated with diabetes mellitus and cardiovascular disease; however, the association between DISH and metabolic syndrome has not been established. The purpose of this study was to investigate a potential association between DISH and metabolic syndrome. Methods We retrospectively reviewed clinical data from consecutive subjects undergoing the musculoskeletal health medical checkups, and enrolled 327 subjects (174 men and 153 women; mean, 63.4 ± 13.7-years). Subjects who had spinal ankylosis at least 4 contiguous vertebral bodies were classified as the DISH group (n = 39) while the others were part of the non-DISH group (n = 288). The definition of the metabolic syndrome comes from diagnostic criteria used by the Japanese Society for Internal Medicine. Age, sex, body max index (BMI), hematological evaluation, blood pressure, presence of metabolic syndrome, the visceral fat area on abdominal computed tomography, and spinal epidural lipomatosis (SEL) on magnetic resonance imaging were evaluated. Results Compared to the non-DISH group, in the DISH group, mean age (DISH group, 74.3 years; non-DISH group, 1.9 years; p < 0.001), male prevalence were higher (DISH group, 82.1%; non-DISH group, 49.3%; p < 0.001), and BMI was greater (DISH group, 24.8; non-DISH group, 23.0; p = 0.006). the metabolic syndrome was more frequently observed in DISH group (28.9%) than in the non-DISH group (16.0%) (p = 0.045). The visceral fat area was significantly larger in the DISH group than in the non-DISH group (DISH group, 130.7 ± 58.2 cm2; Non-DISH group, 89.0 ± 48.1 cm2; p < 0.001). The prevalence of SEL was similar between the 2 groups (10.3% in the DISH group vs. 8.7% in the nonDISH group; p = 0.464). Poisson regression analysis revealed that the metabolic syndrome was significantly associated with DISH with odds ratio of 2.0 (95% confidence interval, 1.0–3.7; p = 0.004). Conclusion Metabolic syndrome was significantly associated with DISH. Our data showed metabolic syndrome is potentially related to DISH.

Study Design: Single-center retrospective study.Purpose: We aimed to explore the postoperative prognostic factors for spinal intramedullary ependymoma.Overview of Literature: Ependymoma (World Health Organization grade II) is the most frequent intramedullary spinal tumor and is treated by total resection. However, postoperative deterioration of motor function occasionally occurs.Methods: Eighty patients who underwent surgical resection at Keio University and Fujita Health University in Tokyo, Japan between 2003 and 2015 with more than 2 years of follow-up were enrolled. A good surgical result was defined as an improvement in the modified McCormick Scale score by one grade or more or having the same clinical grade as was observed preoperatively. Meanwhile, a poor result was defined as a reduction in the McCormick Scale score of one grade or more or remaining in grade IV or V at final follow-up. Univariate and multivariate logistic regression analyses of the following factors were performed in the two groups: sex, age, preoperative Visual Analog Scale (VAS), tumor location, the extent of tumor resection, hemosiderin caps, cavity length, and tumor length on magnetic resonance imaging.Results: At final follow-up, 15 patients were included in the poor results group and 65 in the good results group. In the univariate analysis, the factors related to poor results were as follows: higher age, preoperative McCormick Scale score severity, higher preoperative VAS, thoracic location, hemosiderin capped, and non-gross total resection (GTR). A multiple logistic regression analysis was conducted and showed that age, worse preoperative McCormick Scale score, and non-GTR were significant factors for poor prognosis.Conclusions: The independent risk factors for motor deterioration after ependymoma resection were age, worse preoperative McCormick Scale score, and non-GTR. Early surgery for patients with even mild neurological disorders could facilitate functional outcomes. These results may contribute to determining the optimal timing of surgery for spinal intramedullary ependymoma.

Study Design: This is a retrospective observational study with an outpatient setting.Purpose: This study aimed to describe the effects of duloxetine (DLX) administration for postsurgical chronic neuropathic disorders (both pain and numbness) following spinal surgery in patients without depression.Overview of Literature: Although several reports indicated the potential of DLX to effectively treat postoperative symptoms as a perioperative intervention, there have been no reports of its positive effect on postsurgical chronic neuropathic disorders.Methods: A total of 24 patients with postsurgical chronic pain and/or numbness Numeric Rating Scale (NRS) scores of ≥4 were enrolled. All patients underwent spine or spinal cord surgery at Keio University Hospital and received daily administration of DLX for more than 3 months. The mean postoperative period before the first administration of DLX was 35.5±57.0 months. DLX was administered for more than 3 months at a dose of 20, 40, or 60 mg/day, and the degree of pain and numbness was evaluated using the NRS before administration and 3 months after administration. Effectiveness was defined as more than a 2-point decrease in the NRS score following administration.Results: In terms of the type of symptoms, 15 patients experienced only numbness, eight experienced both pain and numbness, and one experienced only pain. Of the 24 patients, 19 achieved effective relief with DLX. DLX was effective for all patients with postsurgical chronic pain (n=9), and it reduced postsurgical chronic numbness in 18 of 23 patients. No significant difference was observed in background spinal disorders. DLX was not effective for five patients who complained only of postsurgical chronic numbness.Conclusions: This study reports the effectiveness of DLX for postsurgical chronic neuropathic disorders. Although DLX reduced postsurgical chronic pain (efficacy rate=100%) and numbness (78.3%) in certain patients, further investigation is needed to determine its optimal use.

Chin on chest deformity caused by upper cervical kyphosis associated with ankylosing spondylitis is rare. A 66-year-old woman presented at our institute with chief complaints of difficulty in horizontal gaze and opening her mouth. Cervical radiographs showed a C0-2 angle of 1° on flexion and 7° on extension, and her chin-brow vertical angle was 49°. We planned fixation surgery at C0-5 posteriorly to prevent the progression of kyphosis, with slight correction of the kyphosis at C0-2. The correction was performed by pushing down the over lordotically contoured titanium rods connected to an occipital plate onto the C3-5 lateral mass screws, just like cantilever technique. No palpable cracking or loss of resistance was noticed during the correction. However, intraoperative radiographs revealed apparent anterior separation of the vertebral bodies between C3 and C4. Postoperative computed tomography images at the C3/4 level suggested hemorrhage from the fracture site. Tracheostomy was performed because of massive edema around the pharynx. To secure solid bone fusion, staged surgery to extend the fusion to T3 and to graft an additional iliac bone was performed. Fortunately, the C2-7 angle was corrected to 40°, and her chin-brow vertical angle was restored to 17° without any catastrophic complications. Although the patient finally obtained an ideal sagittal alignment, the surgeon should be aware that the technique had a higher perioperative risk for iatrogenic fracture, resulting in neurological and vascular injuries.

Introduction: Osteoporotic vertebral fracture (OVF) is the most common osteoporotic fracture, and some patients require surgical intervention to improve their impaired activities of daily living with neurological deficits. However, many previous reports have focused on OVF around the thoracolumbar junction, and the surgical outcomes of lumbar OVF have not been thoroughly discussed. We aimed to investigate the surgical outcomes for lumbar OVF with a neurological deficit. Methods: Patients who underwent fusion surgery for thoracolumbar OVF with a neurological deficit were enrolled at 28 institutions. Clinical information, comorbidities, perioperative complications, Japanese Orthopaedic Association scores, visual analog scale scores, and radiographic parameters were compared between patients with lower lumbar fracture (L3-5) and those with thoracolumbar junction fracture (T10-L2). Each patient with lower lumbar fracture (L group) was matched with to patients with thoracolumbar junction fracture (T group). Results: A total 403 patients (89 males and 314 females, mean age: 73.8 ± 7.8 years, mean follow-up: 3.9 ± 1.7 years) were included in this study. Lower lumbar OVF was frequently found in patients with lower bone mineral density. After matching, mechanical failure was more frequent in the L group (L group: 64%, T group: 39%; p < 0.001). There was no difference between groups in the clinical and radiographical outcomes, although the rates of complication and revision surgery were still high in both groups. Conclusions: The surgical intervention for OVF is effective in patients with myelopathy or radiculopathy regardless of the surgical level, although further study is required to improve clinical and radiographical outcomes. Level of evidence: Level III

Background The pathogenesis of intervertebral disc (IVD) degeneration is complex and involves the interaction of multiple factors. However, few systemic studies have explored the associations of metabolic disorders and age-related musculoskeletal disorders with the development of IVD degeneration. Methods We analyzed clinical data obtained from healthy individuals who had undergone a musculoskeletal checkup. In total, 276 subjects comprising 142 males and 134 females were enrolled. The subjects were divided into two groups based on the degree of IVD degeneration according to Pfirrmann grading: those with grades 1–3, the group with non-degenerative discs; and grades 4 and 5, the group with degenerative discs. The subjects underwent examinations including abdominal circumference, blood pressure, bilateral hand grip strength, abdominal computed tomography, magnetic resonance imaging of the lumbar spine, and dual X-ray absorptiometry. To examine the independent association with IVD degeneration at L3/4, L4/5, and L5/S levels, we constructed a Poisson regression model and estimated relative risks (RRs) and 95% confidence intervals (CIs) of IVD degeneration. Results Multivariable analysis showed that advanced age was markedly associated with IVD degeneration at all levels and that men had an inverse association with the IVD degeneration, particularly at the L4/5 level (RR = 0.7, 95% CI = 0.6–0.9). In addition, metabolic syndrome was significantly associated with IVD degeneration at the L5/S level (RR = 1.4, 95% CI = 1.1–1.8). Meanwhile, sarcopenia showed no significant association with IVD degeneration at any level. Osteoporosis was inversely associated with IVD degeneration, particularly at the L4/5 level (RR = 0.7, 95% CI = 0.6–0.9). Conclusions Our data suggest that advanced age, female sex, and metabolic syndrome are associated with IVD degeneration. In addition, osteoporosis showed an inverse association with IVD degeneration. Our data should promote understanding of the etiology of lumbar IVD degeneration.

Background Owing to musculoskeletal dysfunction, locomotive syndrome elevates the risk of requiring nursing care. Among degenerative musculoskeletal disorders, lumbar spinal canal stenosis (LSS) associates with locomotive syndrome; however, whether lumbar spinal surgery for LSS improves locomotive syndrome remains unclear. Hence, this study aimed to identify the efficacy of lumbar spinal surgery on locomotive syndrome among elderly patients with LSS. Methods We prospectively collected the clinical data from multiple institutions of patients (age >65 years) who underwent lumbar spinal surgery. Patients were examined for the locomotive syndrome risk test, including the stand-up Test, the two-step Test, and the 25-question risk assessment, 1-day preoperatively and 6-month and 1-year postoperatively. Using a logistic regression model, we identified factors associated with improvement of locomotive syndrome in the total assessment. Results Overall, we examined the data of 166 patients in this study. Upon converting each score of three tests to the stage of locomotive syndrome, the two-step test and the 25-question risk assessment revealed marked improvement in the postoperative distribution of stages. However, the stand-up test revealed a comparable distribution of stages pre- and postoperatively. In the total assessment, the postoperative distribution of stages was significantly improved than that preoperatively. The multivariable analysis revealed that failed back surgery syndrome [odds ratio (OR), 0.2; 95% confidence interval (CI): 0.04–1.05; P = 0.057)] and preoperative stage of 2 in stand-up test (OR, 0.2; 95% CI: 0.05–1.02; P = 0.054) tended to have inverse association with postoperative improvement of locomotive syndrome in the total assessment. Conclusions Lumbar spinal surgery improved the stage of locomotive syndrome among elderly patients with LSS. This study suggests that lumbar spinal surgery for LSS could be beneficial in alleviating locomotive syndrome.

A retrospective multicenter study. Body mass index (BMI) is recognized as an important determinant of osteoporosis and spinal postoperative outcomes; however, the specific impact of BMI on surgery for osteoporotic vertebral fractures (OVFs) remains inconclusive. This retrospective multicenter study investigated the impact of BMI on clinical outcomes following fusion surgery for OVFs. 237 OVF patients (mean age, 74.3 years; 48 men and 189 women) with neurological symptoms who underwent spinal fusion were included in this study. Patients were grouped by World Health Organization BMI categories: low BMI (18.5 kg/m2), normal BMI (≥18.5 and 25 kg/m2), and high BMI (≥25 kg/m2). Patients' backgrounds, surgical method, radiological findings, pain measurements, activities of daily living (ADL), and postoperative complications were compared after a mean follow-up period of 4 years. As results, the proportion of patients able to walk independently was significantly smaller in the low BMI group (75.0%) compared with the normal BMI group (89.9%; P = .01) and the high BMI group (94.3%; P = .04). Improvement in the visual analogue scale for leg pain was significantly less in the low BMI group than the high BMI group (26.7 vs 42.8 mm; P = .046). Radiological evaluation, the Frankel classification, and postoperative complications were not significantly different among all 3 groups. Improvement of pain intensity and ADL in the high BMI group was equivalent or non-significantly better for some outcome measures compared with the normal BMI group. Leg pain and independent walking ability after fusion surgery for patients with OVFs improved less in the low versus the high BMI group. Surgeons may want to carefully evaluate at risk low BMI patients before fusion surgery for OVF because poor clinical results may occur.

Objective: The purpose of our study was to investigate the risk factors of remnant tumor growth after incomplete resection (IR) of cervical dumbbell-shaped schwannomas (DS).Methods: Twenty-one patients with IR of cervical DS with at least 2 years of follow-up were included and were divided into 2 groups: the remnant tumor growth (G) (n = 10) and no growth (NG) (n = 11) groups. The tumor location in the axial plane according to Toyama classification, the location of the remnant tumor margin, and the tumor growth rate (MIB-1 index) index were compared.Results: No significant differences in Toyama classification and MIB-1 index were found. Age was significantly higher in the G group (61.4 years vs. 47.6 years; p = 0.030), but univariate logistic regression analysis revealed little correlation to the growth (odds ratio [OR], 1.08; 95% confidence interval [CI], 1.001–1.166; p = 0.047). Seventeen patients (9 in the G and 8 in the NG group) underwent the posterior one-way approach, and significant differences in the location of the remnant tumor margin were confirmed: within the spinal canal in 1 and 0 case, at the entrance of the intervertebral foramen in 7 and 1 cases, and in the foramen distal from the entrance in 1 and 7 cases, in the G and NG groups, respectively (p = 0.007). The proximal margin was identified as a significant predictor of the growth (OR, 56.0; 95% CI, 2.93–1,072; p = 0.008).Conclusion: Remnant tumors with margins distally away from the entrance of the foramen were less likely to grow after IR of cervical DS.

Study Design: Retrospective single-center study. Objective: We investigated the risk factors of postoperative shoulder imbalance (PSI) in patients with Lenke type 2 adolescent idiopathic scoliosis (AIS) including the position of preoperative upper end vertebra (UEV). Methods: Seventy-five patients with Lenke type 2 AIS who underwent posterior correction and fusion surgeries from 2008 to 2018 were included. We included only patients whose upper instrumented vertebrae were at T2. The patients were divided into 2 groups based on radiographic shoulder height (RSH) at final follow-up, namely PSI group and non-PSI group, and PSI was defined as RSH > 10 mm. UEV, RSH, Cobb angle, curve flexibility, T1 and T2 tilt, correction rate, Risser grade, Scoliosis Research Society-22 scores, and demographic data were compared between the groups using independent t-tests or chi-square tests. Variables with P value < 0.20 in univariate analysis were assessed in logistic regression analysis. Results: Thirty-four patients in the PSI group and 37 patients in the non-PSI group were analyzed. Univariate analysis revealed that there were more patients with UEV at T1 (PSI: 85%, non-PSI: 54%, P < 0.01) and Risser grade ≥ 3 (PSI: 88%, non-PSI: 62%; P < 0.05) in the PSI group than in the non-PSI group. Logistic regression analysis revealed that UEV at T1 (odds ratio [OR] = 4.1 [1.2–14.4], P < 0.05) and Risser grade ≥ 3 (OR = 3.9 [1.1–14.5], P < 0.05) are significantly associated with PSI. Conclusions: UEV at T1 and Risser grade ≥ 3 at the time of surgery are significant risk factors of PSI.

Short stride length is one of clinical symptoms associated with lumbar spinal stenosis (LSS). Short stride is a risk factor for falls; therefore, identification of factors associated with short stride is critical for fall prevention in LSS patients. Although the Two-Step test can conveniently assess maximal stride length, it has not become widely used; therefore, its data are limited. We identified the potential factors associated with short stride of elderly LSS patients using Two-Step test.Clinical data of patients aged65 years who planned to undergo surgery for LSS were prospectively collected at multiple institutions. Patients were assessed with the Two-Step test and Timed Up-and-Go Test prior to surgery; 357 consecutive patients were enrolled. We determined the cut-off value of the Two-Step test score for short stride, referring to the Timed Up-and-Go Test score of 13.5 s, used to indicate high risk of falls in elderly individuals. Logistic regression model was constructed to identify factors associated with short stride.The Two-Step test score showed moderate-to-strong inverse correlation with that of Timed Up-and-Go Test (r = -0.65, p 0.001). Using the tentative Two-Step test cut-off value (0.93) for short stride, multivariable analysis showed that age ≥80 years (OR = 2.3, 95% CI:1.1-4.8), a score of60 for lumbar function in Japanese Orthopedic Association Back Pain Evaluation Questionnaire (OR = 2.7, 95% CI:1.5-4.7), motor deficit (OR = 2.7, 95% CI:1.2-6.1), and sagittal vertical axis ≥50 mm (OR = 2.1, 95% CI:1.2-3.5) were factors significantly associated with short stride in elderly patients with LSS.Using the Two-Step test, we found that 80 years old and over, lumbar dysfunction, motor deficit of the lower extremities, and forward-bent posture were associated with short stride in LSS patients. Therefore, elderly LSS patients with these conditions may have a higher risk for falls.