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Study Design: Retrospective multicenter study., Objectives: To evaluate how preoperative neck pain influences clinical outcomes following posterior decompression for cervical ossification of the posterior longitudinal ligament (OPLL)., Setting: Fourteen medical institutions in Japan., Methods: We enrolled 90 patients with cervical OPLL who underwent posterior decompression and were followed for a minimum of two years. We collected demographic data, medical history, and imaging findings. Patients were divided into two groups based on preoperative neck pain presence (Pre-op. neck pain (-) and (+) groups), and their outcomes were compared., Results: There were no significant differences in patient demographics between the Pre-op. neck pain (-) and (+) groups. Both groups showed similar distributions of ossification types and K-line positivity. Perioperative complications were comparable between the two groups. Radiographic analysis revealed no significant differences in C2-7 angles or cervical range of motion, pre- and postoperatively. Both groups demonstrated significant improvement in postoperative Japanese orthopedic association (JOA) scores, but there were no significant differences in scores or recovery rates. In the Pre-op. neck pain (-) group, factors associated with appearance of postoperative neck pain included pre- and postoperative lower JOA scores and larger C2-7 angles in neutral and extension positions., Conclusions: It emerges that lower pre- and postoperative JOA scores or larger C2-7 angles in neutral and extension positions predispose to postoperative neck pain even in those patients without preoperative neck pain. Therefore, this is worth discussing at the time of consenting patients for surgical decompression and fixation., (© 2024. The Author(s), under exclusive licence to International Spinal Cord Society.)

Purpose: To investigate the influence of slippage reduction and correction of lumbosacral kyphosis by L5-S1 single-level posterior lumbar interbody fusion (PLIF) on spinal alignment and clinical outcomes including postoperative complications in patients with dysplastic spondylolisthesis (DS)., Methods: Twenty consecutive patients with symptomatic and severe DS who underwent L5-S1 single-level PLIF with a minimum of 2 years of follow-up after surgery were included. Clinical outcomes were evaluated using the Japanese Orthopaedic Association (JOA) and visual analog scale (VAS) scores for low back and leg pain obtained on preoperative and postoperative examinations. Postoperative instrumentation failure and L5 radiculopathy were also evaluated. The preoperative and postoperative spinopelvic parameters were measured., Results: The JOA score significantly improved from 21.5 ± 4.8 (preoperative) to 27.0 ± 2.5 (postoperative), with a mean recovery rate of 75.0% ± 30.4%. The VAS score for low back pain significantly improved from 44.5 ± 30.1 (preoperative) to 11.5 ± 15.9 (postoperative), and that for leg pain significantly improved from 31.0 ± 33.2 (preoperative) to 5.0 ± 10.2 (postoperative). The slip percentage (% slip) significantly improved from 59.6% ± 13.5% (preoperative) to 25.2% ± 15.0% (postoperative). The lumbosacral angle (LSA) significantly improved from 12.3° ± 9.5° (preoperative) to 1.0° ± 4.9° (postoperative). L5-S1 PLIF led to significant improvement of lumbar lordosis (from 52.0° ± 15.9° to 59.7° ± 8.0°) and pelvic incidence - lumbar lordosis mismatch (from 23.9° ± 20.6° to 13.3° ± 10.0°). Correction of lumbosacral kyphosis had a significant positive correlation with postoperative pelvic tilt (PT) (r = 0.50, P = 0.02), while postoperative % slip did not have a significant correlation with postoperative PT., Conclusions: L5-S1 PLIF for DS provided good clinical outcomes. Correction of lumbosacral kyphosis had a positive impact on regaining ideal spinopelvic balance and may be beneficial in the setting of treating DS., (© 2024. The Author(s), under exclusive licence to Scoliosis Research Society.)

Study Design: A retrospective comparative study., Objectives: This study aimed to evaluate the radiographical changes in cervical sagittal alignment (CSA) and clinical outcomes after tumor resection using a posterior unilateral approach without spinal fixation for patients with cervical dumbbell-shaped schwannoma (DS)., Methods: Seventy-three patients with DS who were followed up for at least 2 years were included. The Eden classification was used to designate the types of DS. The CSA and range of motion (ROM) were analyzed using radiographs. The clinical outcomes were assessed using the Japanese Orthopaedic Association (JOA) score and JOA cervical myelopathy questionnaire., Results: The CSA in the neutral, flexion, and extension position and cervical ROM were not significantly reduced in the follow-up period. The JOA scores showed significant improvement after surgery. The postoperative radiographic parameters and clinical outcomes of Eden type II or III DS, which needed facetectomy for the resection, did not show any statistically significant difference compared with those of Eden type I tumor, which was resected without facetectomy. Fifty-two cases (71.2%) achieved gross total resection, whereas 21 cases (28.8%) remained in partial resection (PR). One case underwent reoperation due to the regrowth of the remnant tumor whose margin was at the entrance of the intervertebral foramen., Conclusions: Tumor resection using the posterior unilateral approach preserved CSA and resulted in favorable clinical outcomes in patients with DS. When the resection ends in PR, the proximal margin of the remnant tumor should be located distally away from the entrance of the foramen to prevent regrowth., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Intravascular stent (IVaS) is sometimes used for suturing small vessels, but removing the stent after suturing is difficult. To overcome this problem, we developed an IVaS that integrates a stent and a manipulating string. This study aimed to investigate the usefulness of the modified IVaS (M-IVaS) by comparing it with conventional sutures (CS) and conventional IVaS (C-IVaS)., Methods: Forty-five superficial femoral arteries from rats were resected and sutured. The rats were randomly divided into the following 3 groups: CS, M-IVaS, and C-IVaS, with 15 rats per group. Patency rate, operating time, and ultrasonographic blood flow dynamics were examined immediately after suturing. Patency tests, ultrasonographic evaluations, and histological investigations were performed 1 week (n = 5), 2 weeks (n = 5), and 6 weeks (n = 5) after surgery., Results: The 3 groups showed vessel patency in all cases immediately after suturing and at 1 week, 2 weeks, and 6 weeks after surgery. The mean operative time was 22.6 minutes for the CS group, 21.5 minutes for the M-IVaS group, and 25.9 minutes for the C-IVaS group. There were no significant differences in peak flow velocity and stenosis rate among the 3 groups as evaluated by ultrasonography. Histopathological evaluation revealed a similar recovery process of endothelial cells and no damage to the vascular wall., Conclusion: The surgical time using M-IVaS was significantly shorter compared to that using C-IVaS. The M-IVaS reduced the inconvenience of C-IVaS removal. M-IVaS showed the same effectiveness as did the CS in terms of patency rate, operating time, ultrasonographic blood flow dynamics, and histological evaluation. M-IVaS can be used in the field of microsurgery., Competing Interests: Conflicts of interest and sources of funding: The authors are on the following related patents: Patent application of intravascular stent, #2022-121542 filed in the Japan Patent Office. This does not alter our adherence to journal policies on sharing data and materials. The authors have no conflicts of interest to declare., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: Retrospective comparative study., Objective: To evaluate the relationship between pelvic incidence (PI) and proximal junctional kyphosis (PJK) in patients with Lenke type 5 adolescent idiopathic scoliosis (AIS)., Summary of Background Data: Although PJK is a common complication of sagittal malalignment after posterior correction and fusion surgery (PSF), few studies have assessed its risk factors. The significance of pelvic morphology in relation to PJK has been suggested but remains unclear in Lenke type 5 AIS patients., Methods: A total of 92 patients with Lenke type 5 AIS who underwent selective thoracolumbar PSF with a minimum follow-up of two years were included. Patients were divided into PJK and non-PJK groups based on postoperative radiographs. The influence of PI on PJK occurrence was evaluated through binary logistic analysis. Subgroup analysis was performed based on the PI value (low PI,<45°; high PI, ≥ 45°) to identify factors affecting PJK occurrence., Results: PJK was observed in 17.4% of the whole cohort. Binary logistic regression analysis identified low PI and large TL/L curve as a risk factor for PJK (PI, odds ratio, 0.933; TL/L curve, odds ratio, 1.080). Subgroup analysis showed that the postoperative increase in the upper instrumented vertebra slope in PJK cases was comparable in both the low and high PI groups. Meanwhile, lordotic changes in the fused area in the PJK cases were observed only in the low PI group. No difference in the Scoliosis Research Society 22 scores were observed between the two groups., Conclusion: From this study a low PI was identified as a risk factor for the occurrence of PJK in Lenke type 5 AIS patients. The occurrence of PJK is influenced by lordotic changes in the fused area and the limited compensatory capacity of the pelvis in patients with a low PI., Competing Interests: Conflict of interest disclosure: There is no financial conflict of interest to disclose in relation to this work, (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: Retrospective case series., Objective: The aim of this study was to compare the outcomes of posterior decompression surgery for lumbar spinal canal stenosis (LSS) in patients with preoperative sagittal malalignment (MA) with those without, after adjusting for age and sex., Summary of Background Data: Sagittal balance is an important factor in spine surgery and is thought to affect postoperative outcomes after LSS. However, the relationship between sagittal MA and postoperative outcomes has not been thoroughly examined., Patients and Methods: We included 533 patients who underwent surgical treatment for LSS and also achieved 2-year follow-up. Patients were categorized into either an MA+ group (69 patients) or a matched-alignment (MA-) group (348 patients) based on age-adjusted preoperative sagittal alignment. We compared the baseline and 2-year postoperative health-related quality of life (HRQOL) using the Visual Analog Scale and Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ) scores. We also calculated clinical efficacy using the minimal clinically important difference based on JOABPEQ scores, and age and sex-adjusted JOABPEQ scores 2 years after surgery. Differences between groups were examined using the Mann-Whitney U test and χ 2 analysis, where applicable., Results: Both groups showed an improved HRQOL after decompression surgery. Similar proportions of patients showed substantial improvement, as estimated by the minimal clinically important difference, in 4 out of 5 subdomains of the JOABPEQ. A significantly smaller proportion of patients in the MA+ group showed substantial improvement in lumbar function. The age and sex-adjusted HRQOL scores 2 years after surgery were lower in the MA+ group, particularly in the lumbar function and social life function subdomains of the JOABPEQ., Conclusion: The effects of posterior decompression surgery alone can still be observed at least 2 years postoperatively for patients with LSS and concomitant sagittal MA. Patients with sagittal MA may experience lower HRQOL than those without this type of MA., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: Retrospective multicenter study., Objectives: To investigate surgical outcomes following posterior decompression for cervical ossification of the posterior longitudinal ligament (OPLL) when performed by board-certified spine (BCS) or non-BCS (NBCS) surgeons., Methods: We included 203 patients with cervical OPLL who were followed for a minimum of 1 year after surgery. Demographic information, medical history, and imaging findings were collected. Clinical outcomes were assessed preoperatively and at the final follow-up using the Japanese Orthopedic Association (JOA) score and the visual analog scale (VAS) for the neck. We compared outcomes between BCS surgeons, who must meet several requirements, including experience in more than 300 spinal surgeries, and NBCS surgeons., Results: BCS surgeons performed 124 out of 203 cases, while NBCS surgeons were primary in 79 cases, with 73.4% were directly supervised by a BCS surgeon. There was no statistically significant difference in surgical duration, estimated blood loss, and perioperative complication rates between the BCS and NBCS groups. Moreover, no statistically significant group differences were observed in each position of the C2-7 angle and cervical range of motion at preoperation and the final follow-up. Preoperative and final follow-up JOA scores, VAS for the neck, and JOA score recovery rate were comparable between the two groups., Conclusions: Surgical outcomes, including functional recovery, complication rates, and cervical dynamics, were comparable between the BCS and NBCS groups. Consequently, posterior decompression for cervical OPLL is considered safe and effective when conducted by junior surgeons who have undergone training and supervision by experienced spine surgeons., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Competing Interests: Conflicts of Interest: The authors declare that there are no relevant conflicts of interest.

Background/Objectives : An important aspect of the pathophysiology of frailty seems to be the dysregulation of inflammatory pathways and the coagulation system. However, an objective assessment of the impact of frailty on the recovery from surgery is not fully studied. This study sought to assess how frailty affects the recovery of adult spinal deformity (ASD) surgery using blood biomarkers. Methods : 153 consecutive ASD patients (age 64 ± 10 yr, 93% female) who had corrective spine surgery in a single institution and reached 2y f/u were included. The subjects were stratified by frailty using the modified frailty index-11 (robust [R] group or prefrail and frail [F] group). Results of commonly employed laboratory tests at baseline, 1, 3, 7, and 14 post-operative days (POD) were compared. Further comparison was performed in propensity-score matched-39 paired patients between the groups by age, curve type, and baseline alignment. A correlation between HRQOLs, major complications, and biomarkers was performed. Results : Among the propensity-score matched groups, CRP was significantly elevated in the F group at POD1,3(POD1; 5.3 ± 3.1 vs. 7.9 ± 4.7 p = 0.02, POD3; 6.6 ± 4.6 vs. 8.9 ± 5.2 p = 0.02). Transaminase was also elevated in the F group at POD3(ASD: 36 ± 15 vs. 51 ± 58 U/L, p = 0.03, ALT: 32 ± 16 vs. 47 ± 55 U/L, p = 0.04). Interestingly, moderate correlation was observed between transaminase at POD1 and 2 y SRS22 (AST; function r = -0.37, mental health r = -0.39, satisfaction -0.28, total r = -0.40, ALT; function r = -0.37, satisfaction -0.34, total r = -0.39). Conclusions : Frailty affected the serum CRP and transaminase differently following ASD surgery. Transaminase at early POD was correlated with 2 y HRQOLs. These findings support the hypothesis that there is a specific physiological basis to the frailty that is characterized in part by increased inflammation and that these physiological differences persist.

Background: The regenerative and adaptive capacity of skeletal muscles reduces with age, leading to severe disability and frailty in the elderly. Therefore, development of effective therapeutic interventions for muscle wasting is important both medically and socioeconomically. In the present study, we aimed to elucidate the potential contribution of fibro-adipogenic progenitors (FAPs), which are mesenchymal stem cells in skeletal muscles, to immobilization-induced muscle atrophy., Methods: Young (2-3 months), adult (12-14 months), and aged (20-22 months) mice were used for analysis. Muscle atrophy was induced by immobilizing the hind limbs with a steel wire. FAPs were isolated from the hind limbs on days 0, 3, and 14 after immobilization for transcriptome analysis. The expression of ST2 and IL-33 in FAPs was evaluated by flow cytometry and immunostaining, respectively. To examine the role of IL-33-ST2 signaling in vivo, we intraperitoneally administered recombinant IL-33 or soluble ST2 (sST2) twice a week throughout the 2-week immobilization period. After 2-week immobilization, the tibialis anterior muscles were harvested and the cross-sectional area of muscle fibers was evaluated., Results: The number of FAPs increased with the progression of muscle atrophy after immobilization in all age-groups. Transcriptome analysis of FAPs collected before and after immobilization revealed that Il33 and Il1rl1 transcripts, which encode the IL-33 receptor ST2, were transiently induced in young mice and, to a lesser extent, in aged mice. The number of FAPs positive for ST2 increased after immobilization in young mice. The number of ST2-positive FAPs also increased after immobilization in aged mice, but the difference from the baseline was not statistically significant. Immunostaining for IL-33 in the muscle sections revealed a significant increase in the number of FAPs expressing IL-33 after immobilization. Administration of recombinant IL-33 suppressed immobilization-induced muscle atrophy in aged mice but not in young mice., Conclusions: Our data reveal a previously unknown protective role of IL-33-ST2 signaling against immobilization-induced muscle atrophy in FAPs and suggest that IL-33-ST2 signaling is a potential new therapeutic target for alleviating disuse muscle atrophy, particularly in older adults., (© 2024. The Author(s).)

Purpose: This study aimed to examine the changes in thoracolumbar kyphosis (TLK) following correction surgery in patients with Lenke type 5C adolescent idiopathic scoliosis (AIS) and to evaluate its influence on postoperative spinal alignment and clinical outcomes., Methods: Sixty-six patients with Lenke type 5C AIS were included and followed up for a minimum of 5 years after surgery. First, the patients were divided into two groups according to the preoperative TLK angle (Study 1; Kyphosis and Lordosis group). The patients were further classified into two groups according to the presence or absence of postoperative changes in TLK (Study 2; Changed and Maintained groups). Finally, the outcome variables were compared between these groups and analyzed for spinal alignment and clinical outcomes., Results: In Study 1, patients demonstrated a significant kyphotic change in the Lordosis group and a significant lordotic change in the Kyphosis group postoperatively. No statistically significant differences were found between the two groups when comparing the pre- and postoperative coronal and sagittal alignment. In Study 2, there were no statistically significant differences between the Changed and the Maintained groups in each spinal alignment pre- and postoperatively. Each domain of the Scoliosis Research Society 22-item questionnaire remained unchanged at 5 years postoperation., Conclusion: In many patients with Lenke type 5C AIS, TLK changed significantly and approached 0° after surgery. However, the magnitude of the preoperative TLK and the presence or absence of improvement did not affect postoperative spinal alignment. Furthermore, the patients had satisfactory clinical outcomes irrespective of TLK modification., Level of Evidence: III., (© 2023. The Author(s), under exclusive licence to Scoliosis Research Society.)

Purpose: The importance of coronal alignment is unclear, while the importance of sagittal alignment in the treatment of adult patients with spinal deformities is well described. This study sought to elucidate the impact of global coronal malalignment (GCMA) in surgically treated adult symptomatic lumbar deformity (ASLD) patients., Methods: A multicentre retrospective analysis of a prospective ASD database. GCMA was defined as GCA (C7PL-CSVL) ≥ 3 cm. GCMA is categorized based on the Obeid-Coronal Malalignment Classification (O-CM). Demographic, surgical, radiographic, HRQOL, and complication data were analysed. The risk for postoperative GCMA was analysed by univariate and multivariate analyses., Results: Of 230 surgically treated ASLD patients, 96 patients showed GCMA preoperatively and baseline GCA was correlated with the baseline SRS-22 pain domain score (r = - 30). Postoperatively, 62 patients (27%, O-CM type 1: 41[18%], type 2: 21[9%]) developed GCMA. The multivariate risk analysis indicated dementia (OR 20.1[1.2-304.4]), diabetes (OR 5.9[1.3-27.3]), and baseline O-CM type 2 (OR 2.1[1.3-3.4]) as independent risk factors for postoperative GCMA. The 2-year SRS-22 score was not different between the 2 groups, while 4 GCMA patients required revision surgery within 1 year after surgery due to coronal decompensation (GCMA+ vs. GCMA- function: 3.6 ± 0.6 vs. 3.7 ± 0.7, pain: 3.7 ± 0.8 vs. 3.8 ± 0.8, self-image: 3.6 ± 0.8 vs. 3.6 ± 0.8, mental health: 3.7 ± 0.8 vs. 3.8 ± 0.9, satisfaction: 3.9 ± 0.9 vs. 3.9 ± 0.8, total: 3.7 ± 0.7 vs. 3.7 ± 0.7). Additionally, the comparisons of 2-yr SRS-22 between GCMA ± showed no difference in any UIV and LIV level or O-CM type., Conclusions: In ASLD patients with corrective spine surgery, GCMA at 2 years did not affect HRQOL or major complications at any spinal fusion extent or O-CM type of malalignment, whereas GCA correlated with pain intensity before surgery. These findings may warrant further study of the impact of GCMA on HRQOL in the surgical treatment of ASLD patients., (© 2023. The Author(s), under exclusive licence to Scoliosis Research Society.)

Introduction: Precise prediction of hospital stay duration is essential for maximizing resource utilization during surgery. Existing lumbar spinal stenosis (LSS) surgery prediction models lack accuracy and generalizability. Machine learning can improve accuracy by considering preoperative factors. This study aimed to develop and validate a machine learning-based model for estimating hospital stay duration following decompression surgery for LSS., Methods: Data from 848 patients who underwent decompression surgery for LSS at three hospitals were examined. Twelve prediction models, using 79 preoperative variables, were developed for postoperative hospital stay estimation. The top five models were chosen. Fourteen models predicted prolonged hospital stay (≥14 days), and the most accurate model was chosen. Models were validated using a randomly divided training sample (70%) and testing cohort (30%)., Results: The top five models showed moderate linear correlations (0.576-0.624) between predicted and measured values in the testing sample. The ensemble of these models had moderate prediction accuracy for final length of stay (linear correlation 0.626, absolute mean error 2.26 days, standard deviation 3.45 days). The c5.0 decision tree model was the top predictor for prolonged hospital stay, with accuracies of 89.63% (training) and 87.2% (testing). Key predictors for longer stay included JOABPEQ social life domain, facility, history of vertebral fracture, diagnosis, and Visual Analogue Scale (VAS) of low back pain., Conclusions: A machine learning-based model was developed to predict postoperative hospital stay after LSS decompression surgery, using data from multiple hospital settings. Numerical prediction of length of stay was not very accurate, although favorable prediction of prolonged stay was accomplished using preoperative factors. The JOABPEQ social life domain score was the most important predictor., Competing Interests: Conflicts of Interest: The authors declare that there are no relevant conflicts of interest., (Copyright © 2024 The Japanese Society for Spine Surgery and Related Research.)

Background: Although the prognosis of incomplete cervical spinal cord injury (SCI) diagnosed as American Spinal Injury Association Impairment Scale grade C (AIS C) is generally favorable, some patients remain non-ambulatory. The present study explored the clinical factors associated with the non-ambulatory state of AIS C patients., Methods: This study was a single-center retrospective observational study. Seventy-three participants with AIS C on admission were enrolled and divided into two groups according to ambulatory ability after one year. Prognostic factors of SCI were compared in ambulatory (A-group) and non-ambulatory participants (NA-group). Univariable and multivariable logistic regression analyses were performed on demographic information, medical history, mechanism of injury, presence of fracture, ASIA motor scores (MS) of the extremities, neurological findings, including an anorectal examination on admission, and imaging findings., Results: Forty-one patients were included in the A-group and 32 in the NA-group. Univariable analysis revealed that the following factors were related to poor outcomes (p < 0.05): older age, history of cerebrovascular disorder, impairment/absence of S4-5 sensory score, deep anal pressure (DAP) (-), voluntary anal contraction (VAC) (-), anorectal tone (-), anal wink reflex (-), and low MS of the upper and lower extremities. In the multivariable analysis using age, presence or absence of sacral abnormality, and history of cerebrovascular disorders (adjusted for these three factors), older age and presence of sacral abnormality on admission were independent risk factors for a non-ambulatory state at the 1-year follow-up., Conclusions: Incomplete AIS C SCI individuals with older age and/or impairment of anorectal examination could remain non-ambulatory at 1-year follow-up., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2022 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Background: Posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS) has a potential risk for postoperative pleural effusion. Although pleural effusion at an early period after PSF for AIS occurs with a relatively high frequency and occasionally requires some treatments, the impact of postoperative pleural effusion on future pulmonary function or lung volume (LV) has not been clarified to date. The aim of this study was to evaluate the effect of pleural effusion after PSF for AIS on the postoperative pulmonary function and LV., Methods: A total of 114 consecutive patients who underwent PSF for AIS followed up greater than 2 years at our institute were retrospectively reviewed. We evaluated postoperative pleural effusion by computed tomography (CT) at the 1-week follow-up and divided patients into the pleural effusion (PF) and non-pleural effusion (NP) groups. We investigated spirometry parameters recorded for testing included vital capacity (VC), forced expiratory volume in the first second (FEV1), %VC, and FEV1% and measured the LV using CT images and a workstation at baseline and 2 years after surgery., Results: A total of 87 (76.3%) patients with postoperative pleural effusion were identified, but all patients were asymptomatic and did not require additional treatment for postoperative pleural effusion. All pulmonary function parameters at the 2-year follow-up exhibited no significant differences between the two groups. Although preoperative left LV (1.21±0.30 L vs. 1.36±0.34 L; p=.022) and total LV (2.68±0.62 L vs. 2.99±0.73 L; p=.031) were significantly lower in the PF group than in the NP group, all postoperative LV parameters were similar between the two groups., Conclusions: Pleural effusion at an early period after PSF for AIS was a postoperative occurrence without an impact on future pulmonary function and LV., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Author(s).)

Study Design: A retrospective comparative study., Objectives: This study investigated radiographical changes in global spinal sagittal alignment (GSSA) and clinical outcomes after tumor resection without spinal fusion in patients with thoracic dumbbell tumors., Methods: Thirty patients with thoracic dumbbell tumors who were followed up for at least 3 years were included in this study. Variations in the outcome variables were analyzed using individual GSSA parameters measured on radiography. Clinical outcomes were assessed using the modified McCormick scale (MMCS), Japan Orthopaedic Association (JOA) score, and visual analog scale (VAS). To assess the impact of the affected levels on these outcomes, we divided the patients into three groups according to the location of the tumor (upper [T1-4], middle [T5-8], or lower [T9-12] thoracic spine)., Results: The GSSA parameters (cervical lordosis, T1 slope, thoracic kyphosis [global, upper, middle, and lower], thoracolumbar kyphosis, lumbar lordosis, sacral slope, pelvic incidence, and pelvic tilt) of all the patients did not change significantly after surgery. Eleven of thirty patients had preoperative gait disturbances but they could walk without support (MMCS grade I or II) at the final follow-up. The JOA score and VAS showed significant postoperative improvements. No statistically significant differences were observed in each postoperative sagittal profile or clinical outcome between the upper, middle, and lower groups., Conclusions: Tumor resection without spinal fusion did not affect the various GSSA parameters and resulted in satisfactory clinical outcomes, indicating that spinal fusion may not always be necessary when resecting thoracic dumbbell tumors., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Spinal cord injury (SCI) causes severe sequelae and significant social loss, depending on the extent of the damage. Most previous studies have focused on the pathology of the spinal cord to develop treatments for SCI. However, it is now known that the brain, which is not directly damaged, also undergoes morphological changes after spinal cord injury, which could affect natural recovery and treatment. In recent years, magnetic resonance imaging (MRI) has been developed to analyze functional changes in the brain. Resting-state functional MRI (rsfMRI), which captures brain activity at rest, can calculate functional connections between brain areas and identify central hubs by network analysis., Purpose: We aim to investigate functional connectivity in the brain using rsfMRI after SCI and to determine how brain-network main hubs change over time., Methods: We evaluated rsfMRI in 10 mice of the contusional SCI model and calculated connectivity using graph theory. We evaluated "centrality," a representative parameter of network analysis. The subtype of centrality was degree centrality, which indicates the hub function of a single area. The five times of rsfMRI were performed in each individual mouse: before injury and at 1, 3, 7, and 14 weeks post-injury., Results: Before the injury, the degree centralities of the primary and secondary motor cortex were high, suggesting that these motor cortices served as main hubs for motor function. After SCI, the hub function of the motor cortices decreased by 14 weeks. In contrast, hub function in the external capsule and the putamen comparatively increased with time after injury, suggesting that the extrapyramidal/subcortical system, which runs the ventral side of the spinal cord and remains after injury in this model, becomes dominant., Conclusion: We demonstrated the shift of the brain network hub after SCI. The results of this study provide basic information for understanding brain network changes after SCI and would be useful for treatment selection and evaluation of its efficacy in SCI patients., Competing Interests: HO is a compensated scientific consultant at SanBio Co., Ltd. and K Pharma Inc. MN and MS are consultancy scientists at K Pharma Inc. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Matsubayashi, Shinozaki, Hata, Komaki, Nagoshi, Tsuji, Fujiyoshi, Nakamura and Okano.)

Background: Since osteopenia has been reported to potentially associated with the progression of scoliosis, bone mineral density (BMD) might have some influences on adolescent idiopathic scoliosis (AIS). However, little is known about longitudinal BMD changes in AIS patients. This study aimed to investigate whether osteopenia in preoperative AIS patients persist at bone maturity, and to evaluate the association between BMD and AIS severity., Methods: We reviewed 61 AIS patients who underwent surgery when they were Risser grade 4 or below and less than 20 years old (16.6 ± 1.9 years), were followed until they were at least 18 years old and had a Risser grade of 5, and followed at least 2 years after the surgery (mean follow-up 4.9 ± 1.7 years). We evaluated radiographical parameters and proximal femur BMD before surgery and at the final follow-up. A BMD of less than the mean minus 1SD was considered as low BMD. Based on preoperative BMD, 37 patients were assigned to normal BMD (N) group (1.02 ± 0.08 g/cm 2 ) and 24 patients to low BMD (L) group (0.82 ± 0.06 g/cm 2 )., Results: All patients in the N-group had normal BMD at the final follow-up. In the L group, 15 patients (62.5%) had low BMD at the final follow-up (L-L group; preoperative 0.79 ± 0.05 g/cm 2 and final follow-up 0.78 ± 0.05 g/cm 2 ). The mean preoperative Cobb angle was significantly larger in the L-L group (67.8 ± 11.2°) than in those with normal BMD at the final follow-up (L-N group, 55.6 ± 11.8°) or the N-N group (50.8 ± 7.6°). Preoperative BMD was significantly negative correlated with the preoperative Cobb angle. The age at surgery and mean preoperative BMI were similar in the L-N and L-L groups., Conclusions: Of AIS patients with low preoperative BMD, 62.5% still had low BMD after reaching bone maturity, and low BMD was associated with the severity of scoliosis., (Copyright © 2022 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Study Design: Retrospective comparative study., Objectives: The present study investigated radiographical changes in global spinal sagittal alignment (GSSA) and clinical outcomes following tumor resection using spinous process-splitting laminectomy (SPSL) approach without fixation in patients with conus medullaris (CM) or cauda equina (CE) tumor., Methods: Forty-one patients with CM or CE tumor (19 males, 22 females, mean age at surgery of 52.9 ± 13.0 years) were included in this study. The variations of outcome variables were analyzed in various GSSA profiles using radiographic outcomes. The clinical outcomes were assessed using Japan Orthopaedic Association (JOA) score and JOA back pain evaluation questionnaire (JOABPEQ)., Results: In all cases, the various GSSA parameters (sagittal vertical axis, C2-7 lordosis, T1 slope, thoracic kyphosis, T10-L2 kyphosis, lumbar lordosis [LL; upper, middle, and lower], sacral slope, pelvic incidence, and pelvic tilt) did not significantly change in the 2-years postoperative period. Moreover, age at surgery, the number of resected laminae, preoperative T12-L2 kyphosis, or LL did not affect the postoperative changes in T12-L2 kyphosis or LL, and had no statistically significant correlation among them. The scores of each postoperative JOA domain and the Visual Analogue Scale included in the JOABPEQ were significantly improved. There was no statistical significant group difference in each sagittal profile or clinical outcomes between CM and CE groups postoperatively., Conclusions: Tumor resection using SPSL approach did not affected the various GSSA parameters examined and resulted in satisfactory clinical outcomes, indicating that SPSL approach is a suitable surgical technique for patients with CM or CE tumor.

Study Design: Retrospective multicenter study., Objectives: Although surgery is frequently selected for the treatment of idiopathic spinal cord herniation (ISCH), its impact on functional outcomes has yet to be fully understood given the limited number of patients in previous studies. This study aims to evaluate the symptomatic history and surgical outcomes of ISCH., Setting: Three institutions in Japan., Methods: A total of 34 subjects with ISCH were retrospectively enrolled and followed up for at least 2 years. Demographic information, imaging findings, and clinical outcomes were collected. Functional status was assessed using the JOA score., Results: The types of neurologic deficit were monoparesis, Brown-Sequard, and paraparesis in 5, 17, and 12 cases, with their mean disease duration being 1.2, 4.2, and 5.8 years, respectively. Significant differences in disease duration were observed between the monoparesis and Brown-Sequard groups (p < 0.01) and between the monoparesis and paraparesis groups (p = 0.04). Surgery promoted significantly better recovery rates from baseline. Correlations were observed between age at surgery and recovery rate (p < 0.01) and between disease duration and recovery rate (p = 0.04). The mean recovery rates were 82.6%, 51.6%, and 29.1% in the monoparesis, Brown-Sequard, and paraparesis groups, respectively. The monoparesis group had a significantly higher recovery rate than did the Brown-Sequard (p = 0.045) and paraparesis groups (p < 0.01)., Conclusions: Longer disease duration was correlated with the progression of neurologic deficit. Older age, and worse preoperative neurologic status hindered postoperative functional recovery. These results highlight the need to consider surgical timing before neurologic symptoms deteriorate., (© 2023. The Author(s), under exclusive licence to International Spinal Cord Society.)

Competing Interests: Conflicts of Interest: The authors declare that there are no relevant conflicts of interest.

Study Design: A prospective longitudinal magnetic resonance imaging (MRI) study., Objective: The objective of this study was to describe the progression of intervertebral disk (IVD) degeneration in patients who underwent posterior decompression surgery for lumbar spinal canal stenosis (LSS)., Summary of Background Data: IVD degeneration contributes to the pathogenesis of LSS; however, the long-term consequences of degenerative changes after decompression surgery remain unknown., Materials and Methods: Of 258 consecutive patients who underwent posterior lumbar decompression surgery for LSS, 62 who underwent MRI at their 10-year follow-up were included; 17 age-matched asymptomatic volunteers were analyzed as controls. Three MRI findings representing IVD degeneration were graded on their severity: decrease in signal intensity, posterior disk protrusion (PDP), and disk space narrowing (DSN). Clinical outcome was assessed using the low back pain (LBP) score from the Japanese Orthopaedic Association scoring system. We examined the association between the progression of degenerative changes on MRI and LBP/associated factors using logistic regression adjusting for age at baseline and sex., Results: The severity of IVD degeneration tended to be higher in patients with LSS than asymptomatic volunteers at both baseline and follow-up. IVD degeneration progressed in all patients during the 10-year follow-up period. Progression of decrease in signal intensity and PDP was observed at L1/2 in 73% and at L2/3 in 34%, respectively (the highest frequencies in the lumbar spine). Progression of DSN was highest at L4/5 in 42%. The rates of PDP and DSN progression during the 10-year follow-up period tended to be greater in patients with LSS than in asymptomatic volunteers. No significant difference in the proportion of LBP deterioration was evident for individuals with and without MRI findings of progression., Conclusions: Our study reveals a natural history of the long-term postoperative course of IVD degeneration after posterior decompression surgery for LSS. Compared with healthy controls, patients with LSS seemed to be predisposed to IVD degeneration. Lumbar decompression surgery may promote the progression of DSN; however, progression of IVD degeneration after lumbar decompression surgery was not associated with worsening LBP scores., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

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.

Background: Occult proximal femoral fractures do not appear as fracture lines in radiographs, causing misdiagnosis and delayed diagnosis unless additional imaging studies, such as computed tomography or magnetic resonance imaging, are performed. Here, we present a 51-year-old male with an occult proximal femoral fracture who experienced radiating unilateral leg pain that took 3 months to be diagnosed because his symptoms mimicked lumbar spine disease., Case Presentation: A 51-year-old Japanese male experienced persistent lower back and left thigh pain after falling off a bicycle, and was referred to our hospital 3 months thereafter. Whole-spine computed tomography and magnetic resonance imaging revealed minute ossification of the ligamentum flavum at T5/6 without spinal nerve compression, but this did not explain his leg pain. Additional magnetic resonance imaging of the hip joint revealed a fresh left proximal femoral fracture without displacement. He underwent surgery for in situ fixation using a compression hip screw. Post-surgical pain relief was immediate., Conclusions: Misdiagnosis of occult femoral fractures as lumbar spinal disease may occur if distally radiating referred pain is present. Hip joint disease should be considered as a differential diagnosis in cases of sciatica-like pain with an unknown spinal origin and no specific findings on spinal computed tomography or magnetic resonance imaging accounting for the leg pain, especially following trauma., (© 2023. The Author(s).)

Background: 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., Methods: 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., Results: 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)., Conclusions: 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., Competing Interests: Declaration of competing interest Department of Orthopedic Surgery, Keio University of Medicine received a grant for medical research from NuVasive Japan., (Copyright © 2022 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Study Design: This is a single-center retrospective cohort study with a university hospital setting., Purpose: This study aims to evaluate the short-term course of physical function and walking ability after intramedullary spinal cord tumor (ISCT) resection and predict walking independence 1 year after surgery., Overview of Literature: Although several reports have shown the postoperative functional prognosis of spinal intramedullary tumors with long-term follow-up, no reports have identified the predictors associated with the functional outcome at an early stage., Methods: A total of 79 individuals who underwent ISCT resection at our institute between 2014 and 2019 were enrolled in the study, whose preoperative walking state was independent ambulator regardless of cane support with the Functional Independence Measure Locomotor Scale (FIM-L) score of ≥6. The FIM-L, the American Spinal Injury Association (ASIA) motor and sensory scores in the lower extremities, and the Walking Index for Spinal Cord Injury II (WISCI II) were assessed for walking independence, lower-limb function, and walking ability, respectively. These evaluations were performed at 4 time points: preoperatively, 1 week (1W), 2 weeks (2W), and 1 year after surgery., Results: In the early phase after surgery, 71% and 43% of the participants were nonindependent ambulators at 1W and 2W, respectively. Histopathology indicated that patients with solid tumors (ependymoma, astrocytoma, or lipoma) showed significantly lower indices at 1W and 2W than those with vascular tumors (hemangioblastoma or cavernous hemangioma). Regarding tumor location, thoracic cases exhibited poorer lower-limb function at 1W and 2W and poorer walking ability at 2W than cervical cases. According to the receiver operating characteristic (ROC) analysis, 2 WISCI II points at 2W had the highest sensitivity (100%) and specificity (92.2%) in predicting the level of walking independence at 1 year postoperatively (the area under the ROC curve was 0.99 (95% confidence interval, 0.93-1.00)., Conclusions: The higher the lower-limb function scores in the early phase, the better the improvement in walking ability is predicted 1 year after ISCT resection.

Introduction: Adolescent idiopathic scoliosis (AIS) with a major curve at the main thoracic (MT) area is classified as Lenke type 1, 2, or 3 depending on the flexibility of the proximal thoracic (PT) curve and lumbar curve. No definite classification has been established for a major curve at the PT spine. The purpose of this study is to investigate the radiographic characteristics before and after correction surgery for AIS with a major curve at the PT area., Methods: This is a retrospective cohort study at a single academic institution. Twelve patients with a major curve at the PT spine participated in our study and followed for at least two years after surgery. We evaluated the pre- and postoperative Cobb angles of the curve, curve range, location of the apex, sagittal parameters, and shoulder balance-related parameters. All patients were treated by posterior correction and fusion surgery using pedicle screw constructs., Results: The patients were classified as having a double-curve (DC) type, in which the MT curve was structural, or a single-curve (SC) type, in which the MT curve was corrected to less than 25° on supine side-bending films. The mean correction rates for the PT curve were favorable in both groups (DC, 65.7%±9.6%; SC, 39.2%±4.9%). The mean Cobb angle of the lumbar curve improved in the DC group (preoperative, 17.1°±4.0°; postoperative, 5.0°±4.2°) but deteriorated in the SC group (preoperative, 7.1°±1.2°; postoperative, 12.4°±4.4°) after surgery., Conclusions: We illustrated the postoperative radiographical changes of 12 consecutive patients with the major curve at the PT curve. Although posterior correction and fusion surgery corrected the PT curve satisfactorily in both DC and SC patients, the Cobb angle of the lumbar curve deteriorated after surgery in all SC patients. Surgeons need to pay attention to the fusion area, especially LIV, when operating the SC curve type., Competing Interests: Conflicts of Interest: The authors declare that there are no relevant conflicts of interest., (Copyright © 2023 The Japanese Society for Spine Surgery and Related Research.)

Introduction: Pneumonia is one of the leading causes of acute- and chronic-phase mortality in patients with cervical spinal cord injury (CSCI) with quadriplegia. The risk factors for chronic-phase pneumonia recurrence in CSCI are still unknown. This study aimed to investigate the incidence of pneumonia in the chronic phase after injury and to identify its risk factors., Methods: This retrospective clinical observational study included patients with CSCI with American Spinal Injury Association Impairment Scale grades of A or B admitted to our center within 72 h of CSCI injury who started treatment and were available for follow-up for at least 90 days. The patients were assessed for incidences of pneumonia and its associations with clinical characteristics, including risk factors at the time of injury. Patients in whom pneumonia developed within 30 days postadmission and those after 30 days of hospitalization were comparatively examined using univariate and multivariate analyses., Results: Pneumonia occurred in 36% of the 69 enrolled patients throughout the study period and in 20% of all patients after 30 days of hospitalization. Multivariate analysis of risk factors for pneumonia showed that atelectasis (adjusted OR [aOR], 95% confidence interval [CI]: 4.9, 1.2-20.0), enteral feeding (aOR [95% CI]: 13.3 [3.0-58.9]), mechanical ventilation (aOR [95% CI]: 4.0 [1.0-15.0]), and tracheotomy (aOR [95% CI]: 14.6 [2.3-94.6]) within 30 days of admission were significantly associated with the occurrence of pneumonia even after 30 days of hospitalization., Conclusions: The risk factors for developing pneumonia in the chronic phase were atelectasis, enteral feeding, mechanical ventilation, and tracheotomy within 30 days of hospitalization. This study suggests that treatment of atelectasis, long-term respiratory muscle rehabilitation, and training to improve swallowing function are essential to prevent the recurrence of pneumonia after 30 days of hospitalization., Competing Interests: Conflicts of Interest: The authors declare that there are no relevant conflicts of interest., (Copyright © 2023 The Japanese Society for Spine Surgery and Related Research.)

Study Design: Multicenter retrospective study., Objective: This study reports long-term clinical and radiographic outcomes in surgically treated patients with adult symptomatic lumbar deformity (ASLD)., Summary of Background Data: The short-term results of corrective spinal surgery for ASLD are often favorable despite a relatively high complication profile. However, long-term outcomes have not been completely characterized., Methods: A total of 169 surgically treated consecutive ASLD patients (≥50 yr) who achieved minimum 5 year follow-up were included (average 7.5 yr observation window, average age 67±8 yr, 96% female). The subjects were stratified by current age (50s, 60s, and 70s) and compared. Kaplan-Meier analysis was used to estimate the cumulative incidence of unplanned reoperation stratified by age group. Initial and overall direct costs of surgery were also analyzed., Results: The SRS-22 at final follow-up was similar among the three groups (50s, 60s, and 70s; 4.0±0.5 vs. 3.8±0.7 vs. 3.8±0.7, respectively). The overall major complication rate was 56%, and 12% experienced late complications. The cumulative reoperation rate was 23%, and 4% required late reoperation. Patients in their 70s had a significantly higher reoperation rate (33%) and overall complication rate (65%). However, the late complication rate was not significantly different between the three groups (9% vs. 12% vs. 13%). Sagittal alignment was improved at two years and maintained to the final follow-up, whereas reciprocal thoracic kyphosis developed in all age groups. The direct cost of initial surgery was $45K±9K and increased by 13% ($53K±13K) at final follow-up., Conclusions: Long-term surgical outcomes for ASLDs were favorable, with a relatively low rate of late-stage complications and reoperations, as well as reasonable direct costs. Despite the higher reoperation and complication rate, ASLD patients of more advanced age achieved similar improvement to those in the younger age groups., Competing Interests: The authors report no conflicts of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: Retrospective cohort study., Objectives: Intraspinal solitary fibrous tumor (SFT)/hemangiopericytoma (HPC) is often misdiagnosed preoperatively as schwannoma or meningioma because its imaging characteristics are not well understood. As postoperative prognosis differs among the 3 lesions, predicting the probability of SFT/HPC preoperatively is essential. Thus, this study investigates the imaging characteristics of SFT/HPC compared with those of schwannoma or meningioma and evaluates surgical outcomes., Methods: The preoperative imaging findings, tumor resection extent, recurrence and regrowth rates, and neurological improvement were compared between 10 patients with SFT/HPC and 42 patients with schwannoma or 40 patients with meningioma., Results: Most patients with SFT/HPC showed isointensity on both T1- and T2-weighted images compared with patients with schwannoma ( P = 0.011 and 0.029, respectively) and no significant difference compared with patients with meningioma ( P = 0.575 and 0.845, respectively). Almost all patients with SFT/HPC showed highly uniformizing enhancement patterns, similar to those with meningioma ( P = 0.496). Compared with meningioma, SFT/HPC lacked the dural tail sign and intratumoral calcification and exhibited irregular shape. Of the 5 patients who underwent partial resection, 60% exhibited tumor recurrence and regrowth following surgery., Conclusions: Complete en bloc surgical resection should be attempted in patients with intraspinal SFT/HPC to prevent postoperative recurrence or regrowth. As this tumor is often preoperatively misdiagnosed, we recommend that the imaging findings exhibited in this study should be used to positively suspect SFT/HPC. This will enhance patient outcomes by enabling more appropriate preoperative surgical planning.

Study Design: Retrospective case series., Objective: The purpose of this study was to investigate the outcome of multilevel posterior decompression surgery for degenerative lumbar spinal stenosis compared with single-level surgery., Summary of Background Data: The clinical outcomes of multilevel decompression surgery are still controversial because previous studies have not been designed to randomize or adjust the patient background., Materials and Methods: A retrospective review of prospectively collected data from 659 surgically treated lumbar spinal stenosis patients with a minimum 2-year follow-up was performed. Among them, we compared baseline and 2-year postoperative patient-reported outcomes (PROs) including the Visual Analog Scale and Japanese Orthopaedic Association Back Pain Evaluation Questionnaire scores of 122 patients who underwent three or more levels of surgery (M group) and 304 patients who underwent single-level surgery (S group). Further analyses were performed of 116 paired patients from both groups who were propensity score matched by age and baseline PROs., Results: The number of perioperative complications including extradural hematoma, surgical site infection, and spinal fluid leakage [M vs. S: 10 (8%) vs. 19 (6%), P =0.47], and frequency of revision surgery [5 (4%) vs. 23 (8%), P =0.10] were similar between the two groups. In the analysis of propensity score-matched patients, there were comparable improvements in the Visual Analog Scale score for lower back pain (2.6 vs. 2.4, P =0.55), buttock-leg pain (3.1 vs. 3.4, P =0.48), and buttock-leg numbness (2.9 vs. 2.9, P =0.77) in both groups. There were also similar improvements in the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire scores including lower back pain, lumbar function, walking ability, and mental health domains, except for the social life function domain (20.7±26.5 vs. 28.0±27.5, P =0.04)., Conclusions: Despite the longer surgical time and a larger volume of estimated blood loss, multilevel decompression surgery showed similar improvement to that of single-level surgery in terms of recovery of PROs and frequency of revision surgery. Multilevel decompression surgery provides good clinical outcomes with acceptable complication and revision rates when selecting appropriate patient and spinal levels., Competing Interests: The authors report no conflicts of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Introduction: Only a few reports have described the clinical features of recurrent spinal cord tumors. This study aimed to report the recurrence rates (RRs), radiographic imaging, and pathological features of various histopathological recurrent spinal cord tumors using a large sample size., Methods: This study adopted the retrospective observational study design using a single-center study setting. We retrospectively reviewed 818 consecutive individuals operated for spinal cord and cauda equina tumors between 2009 and 2018 in a university hospital. We first determined the number of surgeries and then the histopathology, duration to reoperation, number of surgeries, location, degree of tumor resection, and tumor configuration of the recurrent cases., Results: A total of 99 patients (46 men and 53 women) who underwent multiple surgeries were identified. The mean duration between the primary and second surgeries was 94.8 months. A total of 74 patients underwent surgery twice, 18 patients thrice, and 7 patients 4 or more times. The recurrence sites were broadly distributed over the spine, with mainly intramedullary (47.5%) and dumbbell-shaped (31.3%) tumors. The RRs for each histopathology were as follows: schwannoma, 6.8%; meningioma and ependymoma, 15.9%; hemangioblastoma, 15.8%; and astrocytoma, 38.9%. The RRs after total resection were significantly lower (4.4%) than that after partial resection. Neurofibromatosis-associated schwannomas had a higher RR than sporadic schwannomas (p<0.001, odds ratio [OR]=8.54, 95% confidence interval [95% CI]: 3.67-19.93). Among the meningiomas, the RR increased to 43.5% in ventral cases (p<0.001, OR=14.36, 95% CI: 3.66-55.29). Within the ependymomas, partial resection (p<0.001, OR=2.871, 95% CI: 1.37-6.03) was found to be significantly correlated with recurrence. Dumbbell-shaped schwannomas exhibited a higher RR than non-dumbbell-shaped ones. Furthermore, dumbbell-shaped tumors other than schwannoma had a higher RR than dumbbell-shaped schwannomas (p<0.001, OR=16.0, 95% CI: 5.518-46.191)., Conclusions: Aiming for total resection is essential to prevent recurrence. Dumbbell-shaped schwannomas and ventral meningiomas exhibited higher RR requiring revision surgery. As for dumbbell-shaped tumors, spinal surgeons should pay attention to the possibilities of non-schwannoma histopathologies., Competing Interests: Conflicts of Interest: The authors declare that there are no relevant conflicts of interest., (Copyright © 2023 The Japanese Society for Spine Surgery and Related Research.)

The features of non-neoplastic lesions are often similar to those of intramedullary tumors, and a differential diagnosis is challenging to obtain in some cases. A surgical biopsy, which is performed on highly invasive tumors, should be avoided in cases of non-neoplastic lesions. Therefore, an accurate diagnosis is important prior to treatment. We evaluated 43 patients suspected of having spinal cord tumors and, finally, were diagnosed with non-neoplastic intramedullary lesions via magnetic resonance imaging. The patients commonly presented with myelitis. The patients with non-neoplastic neurological diseases had a significantly shorter symptom duration than those with intramedullary astrocytomas. The proportion of patients with non-neoplastic neurological diseases who presented with lesions at the cervical spinal level and focal lesions on axial imaging but without a spinal cord enlargement was significantly higher than that of patients with intramedullary astrocytomas. The current study aimed to distinguish spinal cord tumors from non-neoplastic intramedullary lesions based on their distinct features.

Background Context: Although the results of decompression surgery for lumbar spinal canal stenosis (LSS) are favorable, it is still difficult to predict the postoperative health-related quality of life of patients before surgery., Purpose: The purpose of this study was to develop and validate a machine learning model to predict the postoperative outcome of decompression surgery for patients with LSS., Study Design/setting: A multicentered retrospective study., Patient Sample: A total of 848 patients who underwent decompression surgery for LSS at an academic hospital, tertiary center, and private hospital were included (age 71±9 years, 68% male, 91% LSS, level treated 1.8±0.8, operation time 69±37 minutes, blood loss 48±113 mL, and length of hospital stay 12±5 days)., Outcome Measures: Baseline and 2 years postoperative health-related quality of life., Methods: The subjects were randomly assigned in a 7:3 ratio to a model building cohort and a testing cohort to test the models' accuracy. Twelve predictive algorithms using 68 preoperative factors were used to predict each domain of the Japanese Orthopedic Association Back Pain Evaluation Questionnaire and visual analog scale scores at 2 years postoperatively. The final predictive values were generated using an ensemble of the top five algorithms in prediction accuracy., Results: The correlation coefficients of the top algorithms for each domain established using the preoperative factors were excellent (correlation coefficient: 0.95-0.97 [relative error: 0.06-0.14]). The performance evaluation of each Japanese Orthopedic Association Back Pain Evaluation Questionnaire domain and visual analog scale score by the ensemble of the top five algorithms in the testing cohort was favorable (mean absolute error [MAE] 8.9-17.4, median difference [MD] 8.1-15.6/100 points), with the highest accuracy for mental status (MAE 8.9, MD 8.1) and the lowest for buttock and leg numbness (MAE 1.7, MD 1.6/10 points). A strong linear correlation was observed between the predicted and measured values (linear correlation 0.82-0.89), while 4% to 6% of the subjects had predicted values of greater than±3 standard deviations of the MAE., Conclusions: We successfully developed a machine learning model to predict the postoperative outcomes of decompression surgery for patients with LSS using patient data from three different institutions in three different settings. Thorough analyses for the subjects with deviations from the actual measured values may further improve the predictive probability of this model., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Competing Interests: Conflicts of Interest: The authors declare that there are no relevant conflicts of interest.

Study Design: Retrospective multicenter study., Objective: To compare the surgical outcomes and complications of posterior decompression between individuals with cervical spondylotic myelopathy (CSM) and those with ossification of the posterior longitudinal ligament (OPLL)., Setting: Seventeen medical institutions in Japan., Methods: This study included 814 individuals with CSM (n = 636) and OPLL (n = 178) who underwent posterior decompression. Propensity score matching of the baseline characteristics was performed to compare surgical outcomes and perioperative complications between the CSM and OPLL groups., Results: Before propensity score matching, the OPLL group had higher percentage of male individuals, body mass index, and number of stenosis levels and longer duration of symptoms (P < 0.01, P < 0.01, P < 0.01, and P < 0.01, respectively). After matching, the baseline characteristics were comparable between the CSM (n = 98) and OPLL (n = 98) groups. The postoperative Japanese Orthopaedic Association (JOA) scores, preoperative-to-postoperative changes in the JOA scores, and JOA score recovery rates were not significantly different between the groups (P = 0.42, P = 0.47, and P = 0.09, respectively). The postoperative visual analog scale (VAS) score for neck pain and preoperative-to-postoperative changes in the VAS score for neck pain were not significantly different between the groups (P = 0.25 and P = 0.50, respectively). The incidence of perioperative complications was comparable between groups., Conclusion: Neurological improvement and complication rates after surgery were comparable between individuals with CSM and those with OPLL, suggesting similar effectiveness and safety of posterior decompression for both conditions., (© 2022. The Author(s), under exclusive licence to International Spinal Cord Society.)

Case: A 45-year-old woman had a grade II chondrosarcoma (T2N0M0G2) located at the spinous processes and laminas of T3-6 with the tumor extension into the spinal canal at T3-4. To perform en bloc tumor resection, we released or disarticulated bilateral costovertebral ligaments from T3-6 and cut the bilateral pedicles at T3-5 all from posteriorly. Then, we completed en bloc resection without violating the tumor capsule., Conclusion: Our novel procedure, bilateral osteotomy of pedicles for en bloc resection successfully allowed for en bloc tumor resection involving the posterior elements with wide surgical margins., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJSCC/B926)., (Copyright © 2022 by The Journal of Bone and Joint Surgery, Incorporated.)

Background: Few studies have examined the changes in cervical sagittal alignment (CSA) and its relationship with other sagittal alignments in AIS patients with major thoracolumbar/lumbar (TL/L) curve who underwent correction surgery. This study investigated the radiographical changes in CSA after correction surgery in patients with Lenke type 6 adolescent idiopathic scoliosis (AIS) and assess any possible factors affecting postoperative CSA., Methods: Forty-four patients with Lenke type 6 AIS (3 males and 41 females, mean age at surgery of 15.6 ± 2.8 years) who could be followed up for 3 years after correction surgery were included in this study. Variations of outcome variables were analyzed in various spinal sagittal parameters using radiographic outcomes. Univariate correlation analyses were used to evaluate possible factors influencing the postoperative CSA. The Scoliosis Research Society (SRS)-22 questionnaires and the Oswestry Disability Index (ODI) were used for clinical evaluation, and the changes between pre- and 3-year post-operation were compared., Results: The Cobb angle of the major and minor curve was significantly improved after correction surgery. Furthermore, CSA, such as C2-7 angle and T1 slope, changed significantly postoperatively. The magnitude of coronal curve correction did not affect CSA postoperatively, while the postoperative TK, T10-L2 kyphosis and LL were significantly correlated with the postoperative C2-7 angle, respectively. None of the patients in this study complained of neck or low back pain during the period up 3 years after the operation. Comparing each domain of SRS-22 or ODI score, these were unchanged between pre-, 1-year, and 3-year post-operation, with no statistically significant differences., Conclusions: CSA changed significantly after correction surgery, and cervical kyphosis indicated a tendency to decrease in Lenke type 6 AIS patients, which was associated with an improvement in thoracic and lumbar sagittal alignment, not correction for coronal deformity., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2022 The Author(s).)

Background: The biopsychosocial mechanism by which exercise leads to improvement in chronic low back pain (CLBP) remains unstudied. This prospective cohort study was performed to examine the effectiveness of exercise on pain, disability, and psychological status for CLBP. We also tested path analytic models in which changes in these variables were included., Methods: CLBP patients who visited the Interdisciplinary Pain Center of Keio University Hospital from July 2018 to April 2020 were included. The propensity score matching was performed between patients who underwent exercise (the exercise group) and those who did not (the control group). At the first visit and at the 3-month follow-up, pain (Numerical Rating Scale (NRS)), disability (Pain Disability Assessment Scale (PDAS)), and psychological status (Pain Self-Efficacy Questionnaire (PSEQ), and Pain Catastrophizing Scale (PCS)) were assessed. Changes in pain and disability at the follow-up were compared between the groups. The relationships between changes in pain, disability, and psychological variables were examined using Pearson's correlation and mediation analysis., Results: A significantly larger decrease in the PDAS was observed in the exercise group ( N  = 49) than in the control ( N  = 49) ( p < 0.05). Increased PSEQ scores were significantly correlated with decreased NRS scores in both groups. In the exercise group, decreased PDAS fully mediated the relationship between increased PSEQ and decreased NRS ( P < 0.05)., Conclusion: Exercise improved disability, and the improved disability by exercise mediated the effect of increased self-efficacy on pain relief in CLBP patients., Competing Interests: The authors declare that there are no conflicts of interest., (Copyright © 2022 Yuta Shinohara et al.)

Background Context: The risk factors for radiographical adjacent segment disease (ASD) in patients with degenerative spondylolisthesis have been previously reported. However, there are only few reports on patients with spondylolytic spondylolisthesis who underwent single-level posterior lumbar interbody fusion (PLIF)., Purpose: The study aimed to investigate the risk factors for radiographical ASD in patients with L5-S1 spondylolytic spondylolisthesis who underwent single-level PLIF., Study Design/setting: A retrospective study PATIENT SAMPLE: This study retrospectively reviewed 135 consecutive patients (91 men and 44 women) with symptomatic L5-S1 spondylolytic spondylolisthesis who underwent single-level PLIF., Outcome Measures: The pre- and postoperative (at the final follow-up) spinopelvic parameters, % slip, sacral slope, lumbar lordosis (LL), pelvic tilt, pelvic incidence (PI), PI minus LL (PI - LL), lumbosacral angle, C7 sagittal vertical axis, and thoracic kyphosis were measured using standing radiographs., Methods: Radiographical ASD was defined as disc height loss (>3 mm), increase of posterior angulation (>5°), or progression of spondylolisthesis (>3 mm) between the pre- and postoperative radiographs. Pfirrmann's classification was used to evaluate disc degeneration. The radiographical parameters and changes between the pre- and postoperative values were evaluated and compared for the non-ASD and ASD groups. Binary logistic regression analysis was performed to evaluate the adjusted associations between each potential explanatory variable and ASD development., Results: The radiographical ASD incidence was 11%. Additionally, 60% of the patients with ASD had radiographical ASD at 1 year and all cases of radiographical ASD in this follow-up period occurred within 3 years after the initial surgery. The mean period of ASD occurrence after initial surgery was 21.7 ± 12.6 months. No patients required reoperation for radiographical ASD. Multivariate analysis revealed that a preoperative (odds ratio [OR], 5.9; 95% confidence interval [CI], 1.2-28.9; p=.03) and a postoperative (OR, 6.5; 95% CI, 1.2-34.5; p=.03) PI - LL of ≥15° were risk factors for radiographical ASD., Conclusions: Pre- and postoperative PI - LL value mismatch was identified as significant independent risk factors for radiographical ASD in patients with L5-S1 spondylolytic spondylolisthesis. Obtaining larger lordosis at L5-S1 may be the key to preventing radiographical ASD., (Copyright © 2022 Elsevier Inc. All rights reserved.)

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.

Study Design: This was a retrospective case series of prospectively collected data., Objective: The present study first described the effect of sublaminar tethering (SLT) on proximal junctional failure (PJF) in adult spinal deformity (ASD) surgery., Summary of Background Data: PJF is a devastating complication following ASD surgery. Teriparatide administration and spinous process tethering have been reported as alternatives for the prevention of PJF, but a clinically effective prevention strategy is still a matter of debate., Materials and Methods: We used data from an ASD database that included 381 patients with ASD (minimum 2-y follow-up). Among them, the data of patients who had a severe sagittal deformity and had surgery from the lower thoracic spine (T9-T11) to the pelvis were extracted and propensity score matched by age, sex, body mass index, bone mineral density, curve type, sagittal alignment, and fused level to clarify whether SLT prevented the development of PJF [SLT vs. control (CTR); age: 67±7 vs. 66±8 y, T-score: -1.4±0.7 vs. -1.3±0.6, body mass index: 22±4 vs. 22±5 kg/m2, C7 sagittal vertical axis (C7SVA): 12±7 vs. 11±5 cm, pelvic incidence-lumbar lordosis (PI-LL): 51±22 vs. 49±21 degrees, pelvic tilt (PT): 36±10 vs. 34±10 degrees, level fused: 11±2 vs. 11±2]. Sixty-four patients were matched into 32 pairs and compared in terms of the postoperative alignment and frequency of PJF., Results: Two years postoperatively, C7SVA and PT were significantly larger in the CTR group, while no significant difference in PI-LL was found (C7SVA: 3±3 vs. 6±4 cm, P<0.01, PT: 16±6 vs. 24±9 degrees, P<0.01, PI-LL: 7±9 vs. 11±11 degrees, P=0.22). The proximal junctional angle was significantly greater in the CTR group (proximal junctional kyphosis: 8±8 vs. 17±13 degrees, P<0.01). The incidence of PJF was significantly lower in the SLT group (3% vs. 25%, P=0.03), with an odds ratio of 0.1 (95% confidence interval: 0.0-0.8, P=0.03)., Conclusion: In the propensity score-matched cohort, the incidence of PJF was significantly lower in the SLT group. SLT is a promising procedure that may reduce the risk of PJF in severe ASD surgery., Competing Interests: The authors declare no conflict of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: Multicenter retrospective study., Objectives: We aim to investigate features of cervical spondylotic myelopathy (CSM) associated with anterior cervical spondylolisthesis (ACS) during posterior decompression surgery., Methods: A total of 732 patients with CSM were enrolled, who underwent posterior decompression surgery between July 2011 and November 2015 at 17 institutions. The patients with ACS (group A), defined as an anterior slippage of ≥2 mm on plain radiographs, were compared with those without ACS (group non-A). Also, the characteristics of patients with ACS progression (group P), defined as postoperative worsening of ACS ≥2 mm or newly developed ACS, were investigated. Moreover, kyphosis was defined as C2-C7 angle in neutral position ≤-5°. The Japanese Orthopedic Association (JOA) scoring system was used for clinical evaluation., Results: Group A consisting of 62 patients (8.5%) had worse preoperative clinical status but comparable surgical outcomes to group non-A. Furthermore, ACS was associated with greater age, and the degree of slippage did not affect myelopathy grades. Seventeen patients (2.3%) were observed in group P, and preoperative ACS was a significant predisposing factor for the progression without clinical impact. Among the patients in group A, preoperative cervical kyphosis was a risk factor for lower JOA recovery rate., Conclusions: Although the presence of ACS increases the risk of postoperative progression, it is not a contraindication for posterior decompression. However, surgeons need to consider the indication of fusion surgery for the patients who have ACS accompanied by kyphosis because of the poor surgical outcomes.

Study Design: This is an international multicenter retrospective review of 219 surgically treated consecutive adult spinal deformity (ASD) patients who had a minimum of five fused segments, completed a 2-year follow-up., Objective: The purpose of this study was to add the indices of preventive procedures to improve and to validate the predictive probability of the PRISM (patient demographics, radiographic index, and surgical invasiveness for mechanical failure) for mechanical failure (MF) following ASD surgery., Summary of Background Data: The PRISM was developed from the data of 321 ASD patients, which stratified the risk of MF from six types of risk., Methods: Data from 136 Japanese ASD patients (age 49 ± 21 yr, 88% female) were used to develop PRISM2, and data from 83 US ASD patients (age 58 ± 12 yr, 86% female) were used for the external validation. We analyzed the associations between three preventive procedures (UIV+1 tethering [TH], teriparatide [TP], and multirod [MR]) and MF by multivariate logistic regression analysis (MRA). The values for the nearest integer of the β of the procedures were added to the six indices of the original PRISM to establish the PRISM2. The discriminative ability of the PRISM/ PRISM2 for MF was evaluated using the area under the receiver operating characteristic curve (AUC) and the precision-recall (PR) curve. The Cochran-Armitage test was used to analyze the trend between PRISM/PRISM2 scores and MF., Results: MF developed in 25% (34 cases). The β values for the preventive procedures calculated by MRA were TH: -2.5, TP: -3.0, and MR: -2.1. The Cochran-Armitage test showed an excellent trend between MF and PRISM/2. The diagnostic ability was superior for the PRISM2 compared with the PRISM (PRISM2; AUC = 0.94 [0.90-0.98], PRISM; AUC = 0.87 [0.81-0.93], difference = -0.07 [-0.11 to -0.03], P  < 0.01). The AUC of the PRISM2 was 0.70 [0.59-0.81, P < 0.01] in the US patient cohort., Conclusion: We refined the PRISM by adding preventive procedures to the risk indices. Further validation and adjustment in a large different patient cohorts may improve the predictive probability of PRISM2.Level of Evidence: 3., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

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., Competing Interests: Declaration of competing interest The authors declare that they have no conflicts of interest., (Copyright © 2021 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Study Design: Multicenter retrospective case series of patients treated surgically for lumbar spinal stenosis (LSS)., Objective: We investigated how laminectomy improves lower back pain (LBP) and the factors associated with poor improvement., Summary of Background Data: Lumbar laminectomy is effective for alleviating neurological symptoms caused by LSS, whereas its effect on LBP is still controversial., Methods: A retrospective review of prospectively collected data from 436 patients (age 72 yrs, 69% males) who underwent laminectomy for LSS with 2 years of follow-up. We analyzed the following risk factors for residual LBP by uni- and multivariate analyses: age, sex, smoking, occupation, comorbidities, frailty, joint replacement, vertebral fracture, DISH, HRQOL, complications, and the presence of spinal instability. The LBP of male and female patients was analyzed after propensity score matching of known confounders. Patient-reported outcomes (JOABPEQ and VAS scores) were obtained at baseline and the 2-year postoperative follow-up., Results: LBP was significantly improved at 2 years post operation (VAS change 2.3 [95% CI 2.0-2.6], P < 0.01). Fifty-five percent of the patients achieved an MCID, with 67% having no or mild LBP. In the multivariate analysis, sex and baseline LBP were independent risk factors (female: OR 1.9 [1.2-3.0], baseline LBP [VAS≥7.5]: OR 1.9 [1.2-3.1]). Furthermore, the independent risk factors for severe baseline LBP were sex and mental status (female: OR 1.7 [1.1-2.7], P = 0.03, mental status: OR 3.8 [2.4-6.0], P < 0.01). However, an analysis of 102 pairs of propensity-score-matched male and female patients showed no difference in the improvement of LBP (male vs. female: VAS 3.8 ± 2.8 vs. 4.0 ± 2.9, P = 0.61, VAS change 3.1 ± 2.9 vs. 2.7 ± 3.0, P = 0.38)., Conclusion: Decompression surgery for LSS significantly improved LBP. Sex and baseline LBP were risk factors for residual LBP. However, when males and females were matched by confounders, no difference was found in the LBP after surgery. Patients with severe baseline LBP may need further evaluation for their mental status because these patients are likely to have mental problems that potentially contribute to persistent LBP.Level of Evidence: 4., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: A retrospective study of consecutive collected data., Objective: To investigate risk factors for postoperative distal adding-on (DA) in Lenke Type 1B and 1C curves using intraoperative radiographs., Summary of Background Data: In adolescent idiopathic scoliosis (AIS), DA radiographic complication can negatively affect postoperative clinical results. However, few studies have focused on assessing risk factors for DA using intraoperative radiographs., Methods: We retrospectively evaluated 69 AIS patients with Lenke Type 1B or 1C curves who underwent posterior selective thoracic fusion. We divided patients into DA and non-DA groups based on radiograph data at 2-year follow-up using Wang et al (Spine 2011) definition of DA. We compared coronal radiographic parameters, including relative positions of end vertebra (EV), stable vertebra (SV), neutral vertebra (NV), and last touching vertebra (LTV) to lowest instrumented vertebra (LIV), and intraoperative radiographic parameters, between the two groups., Results: DA was present in 13 patients (18.8%) at 2-year follow-up. The mean LIV-EV, LIV-NV, LIV-SV, and LIV-LTV relative positions were significantly smaller in the DA group than in the non-DA group. Multivariate analysis showed that LIV-LTV was significantly associated with DA (DA: -0.2 ± 0.7, non-DA: 0.6 ± 0.7). Intraoperative radiographs showed that the mean angulation of the first disc below the LIV after final adjustment was significantly larger in the DA group (2.3° ± 1.1°) than in the non-DA group (0.9° ± 0.7°). Patients whose angulation of the first disc below the LIV was more than 3° were significantly associated with DA., Conclusion: The LIV selected at more cranial to the LTV may be a risk factor for postoperative DA in Lenke Type 1B and 1C curves. Moreover, it was suggested that LIV extension might be considered when the first disc's angulation below the LIV is >3° in intraoperative radiographs.Level of Evidence: 3., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: Retrospective multicenter study., Objective: To identify the impact of the intervertebral level of stenosis on surgical outcomes of posterior decompression for cervical spondylotic myelopathy (CSM)., Summary of Background Data: As the upper affected cervical levels in elderly patients result from degenerative changes in the lower cervical levels with aging, it is usually difficult to determine the influence of the upper affected cervical levels on surgical outcomes after posterior decompression for CSM in older age., Methods: This study involved 636 patients with CSM who underwent posterior decompression. According to the most stenotic intervertebral level, patients were divided into upper (n = 343, the most stenotic intervertebral level was C2/3, C3/4, or C4/5) and lower (n = 293, the most stenotic intervertebral level was C5/6, C6/7, or C7/T1) cervical stenosis groups. Propensity score matching of the baseline factors (characteristics, comorbidities, and neurological function) was performed to compare surgical outcomes, the Japanese Orthopaedic Association (JOA) scores, and visual analog scale (VAS) for neck pain between the upper (n = 135) and lower (n = 135) cervical stenosis groups., Results: Before propensity score matching, age at surgery was older and pre- and postoperative JOA scores were lower in the upper cervical stenosis group (P < 0.001, P < 0.001, and P < 0.001, respectively). Following matching, baseline factors were comparable between the groups. Postoperative JOA scores, preoperative-to-postoperative changes in the JOA scores, and the JOA score recovery rate were not significantly different between the groups (P = 0.866, P = 0.825, and P = 0.753, respectively). No differences existed in postoperative VAS for neck pain and preoperative-to-postoperative changes in VAS for neck pain between the groups (P = 0.092 and P = 0.242, respectively)., Conclusion: The intervertebral level of stenosis did not affect surgical outcomes after posterior decompression for CSM.Level of Evidence: 3., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)