Published papers

Background: Accurate preoperative imaging and intraoperative pathological diagnosis are critical for managing intradural spinal tumors (IDST). This study aimed to assess the diagnostic accuracy of these methods and their impact on reoperation rates. Methods: A retrospective review was conducted on 1383 patients who underwent primary surgical treatment for IDST at a single institution between 2001 and 2022. Preoperative imaging diagnoses were established by spine surgeons and radiologists, while intraoperative pathological assessments were performed using frozen sections with hematoxylin and eosin staining in 929 cases. Final pathological diagnoses were confirmed through immunohistochemistry and genetic analysis. A diagnosis was defined as correct when the final pathology matched either of the two preoperative imaging diagnoses or the intraoperative frozen-section diagnosis. A discrepancy was recorded when the final pathology differed from both. Discrepancy assessments were determined retrospectively from medical records and pathology reports by a single investigator. The accuracy of preoperative imaging and intraoperative pathological diagnoses was compared with final pathology, and reoperation rates were analyzed. Results: The accuracy of preoperative imaging diagnosis was 94.2 %, while that of intraoperative pathological diagnosis was 93.6 %. In subgroup analyses of patients with intraoperative pathology, reoperation was more frequent in cases with inaccurate preoperative imaging compared with accurate imaging (7.7 % vs 2.2 %; P < 0.05). Similarly, intraoperative pathological discrepancies were associated with higher reoperation rates compared with concordant cases (10.2 % vs 2.1 %; P < 0.01). Conclusions: This study demonstrated that both preoperative imaging and intraoperative pathology achieved high diagnostic accuracy in IDST, generally exceeding 90 %. Subgroup analyses suggested that discrepancies in preoperative imaging as well as in intraoperative pathology may be associated with an increased risk of reoperation. These findings indicate that both reliable preoperative imaging and precise intraoperative evaluation could be important for guiding surgical management, while challenges remain in diagnosing rare and histologically diverse tumors. Level of evidence: Level III, retrospective cohort study.

Background Context: Postoperative outcomes in degenerative cervical myelopathy (DCM) vary considerably, yet few studies have characterized the heterogeneous recovery trajectories using longitudinal data. Purpose: To identify distinct postoperative quality of life (QOL) trajectories in DCM patients and determine baseline predictors of recovery patterns. Study Design/Setting: Prospective multicenter observational study. Patient Sample: 977 patients undergoing surgery for DCM across 10 high-volume spine centers in Japan. Outcome Measures: The QOL outcome measure comprised the Short Form-36 physical component summary (PCS) score. Functional outcomes were specifically captured through Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire. Outcomes were measured at baseline, 6, 12, and 24 months postoperatively. Methods: Latent growth mixture modeling was employed to classify patients into distinct postoperative recovery trajectories based on PCS trends. To identify independent predictors of trajectory membership, multinomial logistic regression was performed, with variable selection refined through least absolute shrinkage and selection operator regression (LASSO) regression. Model performance was assessed using area under the receiver operating characteristic curve (AUC) for discrimination and decile-based calibration plots with bootstrap validation. Results: Four distinct PCS recovery trajectories were identified: Low-to-High (L-H, 7.3%), High-to-High (H-H, 44.9%), Low-to-Low (L-L, 37.7%), and Initial-Decline (I-D, 10.1%). Preoperative lower extremity function emerged as the strongest predictor of trajectory class, reflecting the baseline QOL. Additional significant predictors included age, smoking history, symptom duration, and cervical spine function. Particularly, reduced cervical function at baseline was found to be a significant predictor of unfavorable QOL at 24 months. The prediction model demonstrated good discriminatory performance following least absolute shrinkage and selection operator (LASSO) regression for common classes (AUCs: H-H=0.86, L-L=0.80) and moderate performance for L-H class (AUC 0.74). However, accuracy was limited for the I-D class (AUC = 0.63), and calibration was compressed in rarer classes due to class imbalance. Conclusions: Distinct patterns of postoperative recovery exist among DCM patients, with baseline physical function and patient characteristics significantly influencing QOL trajectory. While predictive models reliably distinguished major recovery patterns, less frequent trajectories, particularly those involving deterioration, were difficult to forecast. These findings support the utility of trajectory modeling and patient-reported outcome measures to enhance individualized surgical prognostication in DCM.

Study Design.A retrospective comparative study.Objective.The aim of this study was to examine the changes in cervical sagittal alignment (CSA) following surgical correction in a patient with Lenke type 5 adolescent idiopathic scoliosis (AIS) and evaluate any possible factors influencing postoperative CSA.Summary of Background Data.Few studies have assessed the association between CSA and thoracic or lumbar sagittal alignment in AIS patients with major thoracolumbar/lumbar curve who underwent posterior correction and fusion surgery.Methods.Sixty-six patients with Lenke type 5 AIS (two males and 64 females, the mean age at surgery of 16.2 years) were included in this study. They were followed up for minimum 5 years after surgery. Multiple linear regression analysis was used to evaluate possible factors influencing the postoperative CSA. To determine the influence of upper end vertebra (UEV) level on postoperative CSA, the subjects were divided into two groups according to UEV level of ≥T9 or ≤T10. The outcome variables were compared between the two groups and analyzed for changes in various spinal sagittal profiles using radiographic outcomes.Results.Multiple linear regression analysis revealed that preoperative T10-L2 kyphosis and LL were significantly correlated with postoperative C2-7 lordosis. However, CSA did not significantly change at 5 years after surgery. Sub-analysis of the cohort revealed that in the UEV ≥T9 group, the mean thoracic kyphosis significantly increased from 20.3° ± 10.6° to 24.0° ± 8.9° and the mean C2-7 lordosis also significantly increased from -12.5° ± 8.3° to -4.3° ± 10.3° at 5-year postoperatively. SRS-22 outcomes were comparable between the groups.Conclusion.We indicated that the CSA was not influenced by surgical correction in most Lenke type 5 AIS patients. However, in a patient whose UEV was located at T9 or higher levels, CSA was influenced through the changes in thoracic kyphosis following posterior correction surgery.Level of Evidence: 4.

Study Design: Prospective multicenter cohort study. Objective: To evaluate the impact of surgeon experience on surgical safety, radiographic outcomes, and patient-reported outcomes (PROMs) following anterior cervical discectomy and fusion (ACDF) in patients with cervical degenerative disc disease (CDDD). Methods: This prospective cohort study was conducted at five spine-specialized institutions in Japan. A total of 208 patients with CDDD who underwent ACDF between 2019 and 2022 were enrolled. Procedures were performed by either board-certified spine (BCS) surgeons (n = 150) or non-BCS (NBCS) surgeons (n = 58) under direct BCS supervision. Demographics, surgical variables, radiographic outcomes, and clinical results were compared. Evaluations included surgical duration, estimated blood loss (EBL), complications, cervical alignment and range of motion (ROM), Japanese Orthopaedic Association (JOA) scores, Visual Analog Scale (VAS), JOACMEQ, and SF-36 scores. Results: Surgical duration was comparable between groups, but EBL was significantly greater in the NBCS group (20.2 ± 35.0 mL vs 12.2 ± 13.7 mL, P = .020). Complication rates were low and similar. No major adverse events occurred in either group. Cervical alignment was maintained, and ROM slightly decreased postoperatively without intergroup differences. Both groups showed significant neurological improvement. Gains in JOA scores, reductions in VAS scores, and improvements in JOACMEQ and SF-36 scores were comparable. Conclusions: ACDF performed by NBCS surgeons under BCS supervision achieved clinical outcomes equivalent to those by BCS surgeons. These findings underscore the effectiveness of structured supervision in ensuring surgical safety and fostering competency in spine surgery.

Study design: Retrospective comparative study. Objective: This study aimed to determine whether the degree of preoperative gait disturbance remains following surgical resection in patients with intradural extramedullary spinal cord tumors (IDEMSCTs), and to investigate any factors that may influence poor improvement in postoperative gait disturbance. Setting: The single institution in Japan. Methods: In total, 78 IDEMSCTs patients who required surgical excision between 2010 and 2019 were included. According to the degree of preoperative gait disturbance using modified McCormick scale (MMCS) grade, they were divided into the Mild and Severe groups. The mean postoperative follow-up period was 50.7 ± 17.9 months. Data on demographic and surgical characteristics were compared between the two groups. Results: There was no significant difference in terms of age at surgery, sex, tumor size, surgical time, estimated blood loss, tumor histopathology, and postoperative follow-up period between the Mild and Severe groups. At the final follow-up, 84.6% of IDEMSCTs patients were able to walk without support. Gait disturbance improved after surgery in most of the patients with preoperative MMCS grades II–IV, but remained in approximately half of patients with preoperative MMCS grade V. Age at surgery was correlated with poor improvement in postoperative gait disturbance in the Severe group. Conclusions: Regardless of the degree of preoperative gait disturbance, it improved after tumor resection in most of the IDEMSCTs patients. However, in the preoperative MMCS grade III–V cases, older age at surgery would be an important factor associated with poor improvement in postoperative gait disturbance.

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.

Study design: Retrospective comparative study Objectives: To investigate whether the presence or absence of preoperative lower extremities neurological symptoms (LENS) influences clinical outcomes following tumor resection in patients with cervical intradural extramedullary (IDEM) tumors. Setting: The single institution in Japan. Methods: Ninety-two patients with cervical IDEM tumors requiring surgical resection were included. Based on the degree of preoperative LENS assessed using the modified McCormick scale (MMCS), patients were categorized into LENS (–) and (+) groups. Demographic and surgical characteristics were compared between both groups. Results: There were no significant differences observed in sex, tumor location, tumor size, surgical time, estimated blood loss, approach for tumorectomy, or tumor histopathology between the two groups. Additionally, the overall surgical outcomes were favorable for both groups. At the final follow-up, 91.1% of the patients in the LENS (+) group were able to walk without support. Improvement in LENS was observed after surgery in most patients with preoperative MMCS II–IV, but it persisted in approximately 40% of patients with preoperative MMCS V. In the LENS (+) group, there were no significant differences in demographic or surgical data between the patients with MMCS I and II–III at the final follow-up. Conclusions: Regardless of the presence or absence of preoperative LENS, clinical improvement was observed after tumor resection in most patients with cervical IDEM tumors. These findings suggest that neurological status is likely to improve sufficiently if tumor resection is performed before preoperative LENS deteriorates to an extremely severe stage as MMCS V.

Study Design: Retrospective cohort study. Purpose: To evaluate the effect of discrepancies between sacral and pelvic obliquity on postoperative disk wedging below the lower instrumented vertebra in Lenke type 5 adolescent idiopathic scoliosis (AIS). Overview of Literature: Previous studies have not fully explored the effect of discrepancies between sacral and pelvic obliquity on postoperative outcomes in patients with Lenke type 5 AIS. Methods: Data from 35 patients with Lenke type 5 AIS (mean age, 14.7±1.8 years) followed for a minimum of 5 years were retrospectively analyzed. We investigated the effect of sacral coronal obliquity (S angle) and pelvic coronal obliquity (P angle) on postoperative coronal radiographic parameters. The angle between the S and P angles was defined as the sacral and pelvic (SP) angle. The patients were grouped by preoperative SP angle (<5°, n=23; ≥5°, n=12). Pre- and post-operative radiographic parameters were compared to determine whether the preoperative SP angle affected postoperative spinal alignment. Results: The discrepancy between SP obliquity was reduced by correction surgery 5 years postoperatively. The mean lumbar Cobb angle correction rate in the ≥5° group was significantly lower than that in the <5° group (52.1%±17.8% vs. 65.5%±12.7%), and the mean wedge angle below the lower instrumented vertebra (LIV) in the ≥5° group was significantly larger than that in the <5° group (9.0°±2.6° vs. 4.7°±3.4°) 5 years postoperatively. No significant between-group differences were observed in age, Risser grade, thoracic Cobb angle correction rate, LIV-central sacral vertical line (CSVL), and C7-CSVL. The Scoliosis Research Society-22 outcomes were comparable between the two groups. Conclusions: The ≥5° group exhibited a larger wedge angle below the LIV and lower lumbar Cobb angle correction rate than the <5° group 5 years postoperatively. Preoperative discrepancies between SP obliquity should be considered when planning corrective surgery for patients with Lenke type 5 AIS.

Study Design: This study adopted a cross-sectional study design. Purpose: This study was designed to investigate the effects of bone cross-link bridging on fracture mechanism and surgical outcomes in vertebral fractures using the maximum number of vertebral bodies with bony bridges between adjacent vertebrae without interruption (maxVB). Overview of Literature: The complex interplay of bone density and bone bridging in the elderly can complicate vertebral fractures, necessitating a better understanding of fracture mechanics. Methods: We examined 242 patients (age?>60 years) who underwent surgery for thoracic to lumbar spine fractures from 2010 to 2020. Subsequently, the maxVB was classified into three groups: maxVB (0), maxVB (2–8), and maxVB (9–18), and parameters, including fracture morphology (new Association of Osteosynthesis classification), fracture level, and neurological deficits were compared. In a sub-analysis, 146 patients with thoracolumbar spine fractures were classified into the three aforementioned groups based on the maxVB and compared to determine the optimal operative technique and evaluate surgical outcomes. Results: Regarding the fracture morphology, the maxVB (0) group had more A3 and A4 fractures, whereas the maxVB (2–8) group had less A4 and more B1 and B2 fractures. The maxVB (9–18) group exhibited an increased frequency of B3 and C fractures. Regarding the fracture level, the maxVB (0) group tended to have more fractures in the thoracolumbar transition region. Furthermore, the maxVB (2–8) group had a higher fracture frequency in the lumbar spine area, whereas the maxVB (9–18) group had a higher fracture frequency in the thoracic spine area than the maxVB (0) group. The maxVB (9–18) group had fewer preoperative neurological deficits but a higher reoperation rate and postoperative mortality than the other groups. Conclusions: The maxVB was identified as a factor influencing fracture level, fracture type, and preoperative neurological deficits. Thus, understanding the maxVB could help elucidate fracture mechanics and assist in perioperative patient management.

Study Design: Retrospective multicenter study. Objectives: To investigate the impact of preoperative cervical range of motion (ROM) on clinical outcomes after posterior decompression for cervical ossification of the posterior longitudinal ligament (OPLL). Methods: We analyzed data from 156 patients with cervical OPLL who underwent posterior decompression and were followed for at least 2 years. Patients were divided into two groups based on preoperative gap ROM, which was a novel indicator representing the difference between flexion and extension ROM: the gROM <0° and >0° groups, and their outcomes were compared. Results: There were no significant differences in patient demographics or surgical details between the gROM <0° and >0° groups. The gROM <0° group exhibited less lordosis in C2-7 angles before and after surgery compared to the gROM >0° group. Cervical ROM significantly decreased following posterior decompression regardless of whether preoperative gROM was <0° or >0°. Meanwhile, the incidence of perioperative complications was similar between the two groups. Furthermore, both groups showed significant improvement in Japanese Orthopaedic Association (JOA) scores postoperatively; however, there were no significant group differences in JOA scores, recovery rates, or visual analog scale for neck pain between the two groups at the preoperation and final follow-up. Conclusions: The incidence of perioperative complications and postoperative clinical outcomes were comparable regardless of the magnitude of preoperative cervical gROM. Although cervical ROM decrease postoperatively, posterior decompression for cervical OPLL can offer favorable clinical outcomes irrespective of the preoperative cervical ROM magnitude, consequently.

Introduction: Surgical interventions for cervical spine and spinal cord diseases may lead to life-threatening postoperative airway obstruction, requiring urgent airway management. This study aimed to assess the feasibility and effectiveness of our respiratory management protocol for patients undergoing anterior cervical approaches, posterior occipitocervical fusion, and intramedullary tumor resection. Methods: This single-center retrospective study consisted of 497 patients who underwent cervical surgeries, including anterior fusion, posterior occipitocervical fusion, combined anterior and posterior fusions, and intramedullary tumor resection between January 2006 and June 2022. Our institution implemented a specific postoperative airway management protocol from September 2014 onward. The protocol involved continued intubation for at least the first postoperative night, followed by a spontaneous breathing trial with a cuff leak test and extubation one or more days after surgery. We compared the outcomes between the pre-protocol period (non-protocol group, n=234) and the protocol period (protocol group, n=263). Results: There were no significant between-group differences regarding demographic, clinical, or surgical details. In the non-protocol group, four subjects required reintubation because of postoperative airway complications (anterior fusion: 1 patient, posterior occipitocervical fusion: 1 patient, and intramedullary tumor resection: 2 patients). After the airway protocol implementation, the reintubation rate dropped to zero (P=0.048). Conclusions: Our airway management protocol substantially reduced the need for reintubation. These findings emphasize the importance of postoperative respiratory management after cervical spine surgeries and underscore the need for appropriate measures to prevent complications.

Study design: Retrospective cohort study. Objectives: Due to the rarity of intradural spinal tumors (ISTs) in individuals under 20, comprehensive studies are lacking. This study aims to compare the clinical data of intramedullary and extramedullary IST cases in patients under 20 years of age with those of adult cases and to identify functional predictors that affect surgical outcomes. Setting: The single institution in Japan. Methods: This retrospective study included 1367 patients diagnosed with extramedullary or intramedullary ISTs who underwent surgery at our institution from 2001 to 2021. Patients were divided into two groups: under 20 years old (Under-20) and 20 years and older. Collected data included demographics, magnetic resonance imaging (MRI) results, and surgical and clinical information. Neurological status was evaluated using the modified McCormick Scale (mMS). Results: Among 1367 cases, 55 patients (4.0%) were under 20 years old. The most frequent tumors in the Under-20 group were astrocytoma (18.2%), followed by myxopapillary ependymoma (16.4%). Seven patients in the Under-20 group died during follow-up. Among the surviving patients, unstable gait post-surgery was associated with malignant tumors and worse preoperative mMS scores. Conclusions: This study highlights significant differences in IST epidemiology and pathology between minors and adults, emphasizing the need for early MRI to prevent paralysis progression and improve outcomes. Understanding these differences is crucial for effective diagnosis and treatment during the first two decades of life.

Objective: To determine the effects of exercise on trunk performance and balance in patients with spinal cord injury (SCI). Methods: We searched the databases MEDLINE, Cochrane Library, EMBASE, Physiotherapy Evidence Database, Web of Science, PsycINFO, and CINAHL from inception to June 2020. Our search targeted studies such as randomized or non-randomized controlled trials and randomized crossover trials that evaluated the effects of exercise on trunk performance and balance in patients with SCI. Results: Seventeen eligible studies with 432 patients with SCI were included in the meta-analysis. The exercise significantly improved several measures: Berg Balance Scale (mean differences [MD] = 4.58; 95% confidence intervals [CI], 0.35, 8.8; p = 0.03), Modified Functional Reach Test (MD = 5.29; 95% CI, 4.16, 6.42; p < 0.01), T-shirt test (MD = 5.62; 95% CI, − 3.82, − 7.42; p < 0.01), Timed Up and Go (MD = − 1.70; 95% CI, − 0.23, − 3.16; p = 0.02). Improvements were also noted in total static sitting balance (standardized mean differences [SMD] = 1.21; 95% CI, 0.79, 1.63; p < 0.01), and total dynamic sitting balance (SMD = 1.01; 95% CI, 0.30, 1.73; p < 0.01). In the subgroup analysis, exercise with sensory input enhancement significantly improved total static (SMD = 1.37; 95% CI, 0.64, 2.11; p < 0.01) and total dynamic sitting balance (SMD = 1.78; 95% CI, 0.28, 3.29; p = 0.02). Conclusions: Exercise may improve sitting balance in patients with SCI. Moreover, enhancement of sensory input had an add-on effect in improving sitting balance. Registration: PROSPERO (CRD42020185904).

Introduction: Our group has conducted extensive basic and preclinical studies of the use of human induced pluripotent cell (iPSC)-derived neural stem/progenitor cell (hiPSC-NS/PC) grafts in models of spinal cord injury (SCI). Evidence from animal experiments suggests this approach is safe and effective. We are preparing to initiate a first-in-human clinical study of hiPSC-NS/PC transplantation in subacute SCI. Setting: NS/PCs were prepared at a Good Manufacturing Practice-grade cell processing facility at Osaka National Hospital using a clinical-grade integration-free hiPSC line established by the iPSC Stock Project organized by the Kyoto University Center for iPS Cell Research and Application. After performing all quality checks, the long-term safety and efficacy of cells were confirmed using immunodeficient mouse models. Methods: The forthcoming clinical study uses an open-label, single-arm design. The initial follow-up period is 1 year. The primary objective is to assess the safety of hiPSC-NS/PC transplantation in patients with subacute SCI. The secondary objective is to obtain preliminary evidence of its impact on neurological function and quality-of-life outcomes. Four patients with C3/4-Th10 level, complete subacute (within 24 days post-injury) SCI will be recruited. After obtaining consent, cryopreserved cells will be thawed and prepared following a multi-step process including treatment with a γ-secretase inhibitor to promote cell differentiation. A total of 2 × 106 cells will be transplanted into the injured spinal cord parenchyma 14–28 days post-injury. Patients will also receive transient immunosuppression. This study protocol has been reviewed and approved by the Certified Committee for Regenerative Medicine and the Japanese Ministry of Health, Labor and Welfare (University Hospital Medical Information Network Clinical Trials Registry [UMIN-CTR] number, UMIN000035074; Japan Registry of Clinical Trials [jRCT] number, jRCTa031190228). Discussion/conclusion: We plan to start recruiting a patient as soon as the COVID-19 epidemic subsides. The primary focus of this clinical study is safety, and the number of transplanted cells may be too low to confirm efficacy. After confirming safety, a dose-escalation study is planned.

Study design: Retrospective cohort study. Objectives: To evaluate surgical consistency and clinical outcomes in intramedullary ependymoma (WHO grade II) cases by using X-bar charts as a tool to assess procedural stability. Setting: The single institution in Japan. Methods: This study included patients who underwent resection of intramedullary ependymomas between 2001 and 2023. All surgeries were performed by one of five board-certified spine surgeons. Operative time was analyzed for stability using X-bar charts. Neurological outcomes were assessed using the modified McCormick Scale (mMS), and regression analysis was performed to evaluate the relationship between operative time and mMS. Results: The study included 144 patients (82 men, 62 women; average age 50.3 ± 14.6 years). Tumors were located at cervical (67.4%) or thoracic (32.6%) levels, averaging 3.0 ± 1.2 vertebrae. The surgeon who performed 71 cases was defined as the experienced surgeon, and the other surgeons performed 10–24 cases, respectively. The mean operative time was 380.6 ± 140.7 min, and 135 cases achieved gross total resection. The average follow-up duration was 6.9 ± 3.9 years. X-bar charts showed surgical stability once the average number of cases exceeded 17. No significant correlation was found between operative time and mMS for any surgeon. Perioperative complications were minimal. Conclusions: X-bar charts are a valuable tool for objectively evaluating surgical stability. In intramedullary ependymoma surgeries, consistency in operative time was achieved after 17 cases, and longer procedures did not adversely affect neurological outcomes. This method could be extended to monitor procedural reliability in other complex surgical interventions.

Study Design: Retrospective multi-institutional study. Objectives: Although previous studies have evaluated the surgical outcomes of laminoplasty in patients with cervical ossification of the posterior longitudinal ligament (OPLL), the long-term results remain unclear. The purpose of this study is to assess outcomes more than 10 years post-surgery and identify to identify factors that affect the long-term prognosis. Methods: Eighty-four OPLL patients with more than a minimum of 10-year follow-up after surgery were divided into a good group with more than 50% improvement of the recovery rate of the cervical Japanese Orthopaedic Association (JOA) score, and a poor group with less than 50% improvement. The demographic data and radiographic parameters of cervical spinal alignment were compared, and significant poor prognostic factors were evaluated by multivariate logistic regression. Results: Four preoperative factors showed significant differences between 2 groups: the presence of type 2 diabetes (P = 0.012), the baseline JOA scores (P = 0.001), the narrowest segment in the cervical (P < 0.001) and the presence of T2-weighted high signal on MRI (P = 0.030). Logistic regression analysis identified 3 of 4 factors were significantly associated with postoperative poor outcomes: the presence of type 2 diabetes (P = 0.011), the baseline JOA scores (P = 0.022), and the presence of T2-weighted high signal on MRI (P = 0.035). Conclusion: This study identified three risk factors associated with poor long-term surgical outcomes following laminoplasty for cervical OPLL. These findings could be significant indicators for predicting long-term outcomes in cervical OPLL patients.

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: 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.

Study Design. – Prospective multicenter cohort study. Objectives. – To investigate the impact of symptom duration on surgical outcomes and functional recovery in patients with degenerative cervical myelopathy (DCM). Methods. – A total of 874 patients with DCM who underwent surgery across 10 institutions were analyzed. Patients were stratified into four groups according to symptom duration: <0.5 years, 0.5–2 years, 2–5 years, and ≥5 years. Clinical outcomes, including JOA score, SF-36, VAS, NPSI, and JOACMEQ, were assessed preoperatively and at 2-year follow-up. The minimum clinically important difference (MCID) was defined as 2.5 points for JOA and 4.0 points for PCS. Multivariate analyses were performed to identify associations between symptom duration and outcomes, adjusting for relevant covariates. Results. – All groups exceeded the MCID for ΔJOA. However, only patients with<2 years of symptoms achieved a ΔPCS exceeding the MCID. Shorter symptom duration was associated with better recovery in extremity and bladder function, as well as quality of life, as assessed by the JOACMEQ. Conclusion. – Although neurological recovery exceeded the MCID even after five years of symptoms, patient-reported physical function fell below the MCID beyond two years. This discrepancy underscores the importance of performing surgical intervention within two years of symptom onset to optimize both clinical and patient-centered outcomes.

Background: No study has assessed the incidence or predictors of postoperative shoulder imbalance (PSI) in patients with Lenke type 5C adolescent idiopathic scoliosis (AIS) who underwent selective anterior spinal fusion (ASF). This study evaluated the incidence and predictors of shoulder imbalance after selective ASF for Lenke type 5C AIS. Methods: In total, 62 patients with Lenke type 5C AIS (4 men and 58 women, mean age at surgery of 15.5 ± 1.5 years) were included and divided into the following two groups according to the radiographic shoulder height (RSH) at the final follow-up: PSI and non-PSI groups. All patients in this study underwent a whole-spine radiological evaluation. Various spinal coronal and sagittal profiles on radiographs were compared between the 2 groups. The clinical outcomes were assessed using the Scoliosis Research Society (SRS)-22 questionnaires. Results: The mean final follow-up duration was 8.6 ± 2.7 years. PSI was observed in 10 patients (16.1%) immediately after surgery; however, in the long-term follow-up period, PSI improved in 3 patients spontaneously, whereas the remaining 7 patients had residual PSI. The preoperative RSH and correction rates of the major curve immediately after surgery or at the final follow-up were significantly larger in the PSI group than in the non-PSI group (p=.001, p=.023, and p=.019, respectively). Receiver operating characteristic curve analysis indicated that the cutoff values for preoperative RSH and the correction rates immediately after surgery and at the final follow-up were 11.79 mm (p=.002; area under the curve [AUC], 0.948), 71.0% (p=.026; AUC, 0.822), and 65.4% (p=.021; AUC, 0.835), respectively. No statistically significant difference was observed in the preoperative and final follow-up SRS-22 scores in any domain between the PSI and non-PSI groups. Conclusions: Paying attention to the preoperative RSH and avoiding excessive correction of the major curve can prevent the occurrence of shoulder imbalance after selective ASF for Lenke type 5C AIS.