Published papers

Objective: To examine the factors influencing cervical sagittal alignment (CSA) after posterior correction and fusion surgery (PSF) for patients with Lenke type 2 adolescent idiopathic scoliosis (AIS). Methods: A total of 102 female patients with Lenke 2 AIS and a minimum 2-year follow-up were included. The upper instrumented vertebra was T2 in all patients. Sagittal and coronal parameters were measured before and 2 years after surgery. Patients were categorized into cervical malalignment (CM) and noncervical malalignment (NCM) groups following Passias’ criteria. Radiographic factors influencing CSA were analyzed. Results: Preoperatively, 57 patients (55.9%) were assigned to the CM group and 45 patients (44.1%) to the NCM groups. The cervical lordosis (CL) in CM group was more kyphotic (19.3° vs. 3.3°), smaller proximal thoracic kyphosis (PTK; 9.7° vs. 15.4°), and smaller T1 slope (7.1° vs. 14.0°) than those in the NCM group. Main thoracic kyphosis (MTK) did not show significantly difference between the 2 groups (11.3° vs. 14.4°). Two years after surgery, the CM group demonstrated significant improvements in CSA. PTK increased from 9.7° to 13.5°, T1 slope increased from 7.1° to 10.5°, and cervical kyphosis improved from-19.3° to-8.8°, while MTK remained unchanged (11.3° vs. 11.6°). Conclusion: PSF significantly improved CSA in patients with preoperative CM. Increased PTK, correlated with improved CL, suggests that PSF-induced PTK enhancement, rather than MTK, drives T1 slope and subsequent CSA improvement.

Study Design. – Prospective multicenter cohort study. Objectives. – To investigate the postoperative recovery trajectory of preoperative neurogenic bladder dysfunction (NBD) in patients with degenerative cervical myelopathy (DCM) and identify factors linked to persistent NBD after surgery. Summary of Background Data. – Although surgical intervention typically enhances neurological function, post-surgery bladder function recovery varies and may not align with improvements in other neurological areas. Longitudinal data on the postoperative progression of bladder functional recovery remain limited. Methods. – This prospective study included 352 DCM patients with preoperative NBD who underwent surgery. Patients were categorized into a full recovery group (Japanese Orthopaedic Association [JOA] bladder function score = 3 at 2-year) or a persistent dysfunction group (≤2). Patient-reported bladder outcomes were evaluated using the JOA Cervical Myelopathy Evaluation Questionnaire (JOACMEQ). General health-related quality of life was assessed using the Short Form36 Health Survey (SF-36). Binary logistic regression analysis was conducted to identify factors associated with persistent NBD. Results. – NBD showed progressive improvement over time, and 2-year post-surgery, 71.3% of patients achieved complete recovery of bladder function. Older age at the time of surgery (odds ratio [OR], 1.029; 95% confidence interval [CI], 1.002–1.055) and lower preoperative JOA bladder function scores (OR, 0.631; 95% CI, 0.406–0.982) were independently associated with postoperative persistent NBD. The overall effective rate based on the JOACMEQ bladder function domain was 26.5%, with higher postoperative scores and effective rates observed in the full recovery group. The SF-36 Physical and Mental Component Summary scores showed no significant intergroup differences. Conclusions. – Approximately 70% of patients with DCM and preoperative NBD achieved complete bladder functional recovery within 2-year post-surgery. Postoperative bladder functional recovery was mainly influenced by patient age and baseline NBD severity, following a recovery pattern that was distinct from other neurological domains. Bladder-specific evaluation remains crucial for postoperative assessment and patient counseling in DCM. Level of Evidence. – II

Study design: Prospective multicenter cohort study. Objectives: Degenerative cervical myelopathy (DCM) is the leading cause of spinal cord dysfunction in adults, yet the duration and trajectory of postoperative recovery remain incompletely defined. Although registry studies suggest that most recovery occurs within the first postoperative year, comprehensive multicenter evidence using patient-reported outcomes (PROs) is limited. Methods: This multicenter study included 935 patients who completed at least one clinical or radiographic assessment at 24 months. Clinical characteristics, radiographic parameters, and PRO instruments—including VAS, JOACMEQ, SF-36, and NPSI—were collected preoperatively and at 6, 12, and 24 months postoperatively. Longitudinal changes were analyzed using linear mixed-effects models adjusted for demographic and clinical covariates. Results: Most PROs showed substantial improvement by 6 months and remained largely stable through 24 months. Neck and shoulder pain and pain from the chest to the toes plateaued after early improvement, whereas arm and hand symptoms continued gradual gains. JOACMEQ domains related to cervical function, upper extremity function, and QOL remained stable, while lower extremity function declined modestly and bladder function returned to near-baseline by 24 months. SF-36 PCS/MCS and NPSI scores improved early and were maintained. Radiographically, cervical lordosis showed a slight postoperative decrease without further progression, and cervical ROM decreased after surgery but remained stable. Conclusion: Substantial recovery was already evident by the 6-month assessment, with minimal additional gains thereafter. These findings highlight the importance of early postoperative assessment and may guide optimization of follow-up strategies and perioperative care.

This case report describes a 13-year-old female patient with adolescent idiopathic scoliosis (AIS) and flat back who experienced progressive kyphotic deformity after implant removal despite obtaining physiological alignment postoperatively. The patient underwent multiple surgeries, and a late-developing infection complicated her treatment course. Despite hard bracing to prevent kyphotic change, the kyphosis progressed to 74° within a year after implant removal, leading to a decrease in patient height and back pain. Revision surgery was eventually necessary. Possible factors for the kyphotic progression include injury to paraspinal back muscles due to multiple surgeries or insufficient bony fusion from late-developing infection. This case highlights the importance of thorough evaluation and follow-up for optimal patient outcomes after implant removal in AIS patients, particularly those with flat back.

Study Design: Prospective multicenter cohort study. Objectives: To determine the incidence and risk factors for postoperative complications following cervical spine surgery and to explore their association with long-term clinical outcomes. Methods: A total of 1482 patients with degenerative cervical disorders who underwent surgery at 10 high-volume institutions in Japan were prospectively enrolled. Perioperative complications were defined as events occurring within 30 days postoperatively. Risk factors were analyzed using univariate and logistic regression analyses. Clinical outcomes were assessed using the cervical Japanese Orthopaedic Association (JOA) score and the Physical Component Summary (PCS) of the SF-36 at baseline and 2 years postoperatively. Results: Perioperative complications occurred in 5.5% of patients: segmental motor paralysis (2.3%), neurological deficit (0.6%), dural tear (0.5%), CSF leakage (0.3%), epidural hematoma (0.9%), and surgical site infection (0.8%). Male sex (OR 3.049; 95% CI 1.045-8.929) and posterior fusion (OR 4.016; 95% CI, 1.518-10.620) were significant risk factors for segmental motor paralysis, while respiratory disease (OR 5.500; 95% CI, 1.462-20.694) was associated with surgical site infection. At 2 years, patients with complications showed variable neurological recovery, with many failing to reach the minimum clinically important difference. Conclusions: Male sex, posterior fusion, and respiratory disease were identified as significant risk factors for major complications. Awareness of these factors may support improved surgical planning and perioperative management. However, interpretation of long-term outcomes should be made with caution because of the limited number of cases and potential selection bias associated with incomplete follow-up.

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.

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.

Study design: Retrospective chart audit. Objectives: This study aimed to identify conventional routine blood testing biomarkers associated with the progression of intramedullary injured area in patients with spinal cord injury (SCI). Setting: A spinal cord injury center in Hokkaido, Japan. Methods: We retrospectively reviewed 71 consecutive adults with acute SCI who were admitted within 24 h after injury and diagnosed as American Spinal Injury Association Impairment Scale Grade A or B at admission. Participants were divided into the progression (P group) and no progression group (NP group) based on the change of the hyperintense signal abnormality in the spinal cord on magnetic resonance imaging from the time of admission to 4 weeks after injury. Individual characteristics and blood testing data obtained in the first 4 weeks after injury were compared between groups. Results: The P and NP groups were comprised of 16 and 55 participants, respectively. In univariate analyses, white blood cell (WBC) count on day 3 was significantly higher in group P than group NP (P = 0.021), as was serum C-reactive protein (CRP) level on day 3 (P = 0.015) and day 7 (P = 0.047). Multivariable analysis identified serum CRP level on day 3 as a significant independent prognostic factor for the progression of secondary SCI (OR, 1.138; 95% confidence interval, 1.01–1.28; P = 0.034). Conclusions: Serum CRP level on day 3 after injury was a good predictor for the progression of intramedullary signal intensity change on MRI from acute to subacute stage in patients with SCI.

Case:A 7-year-old boy with chondrodysplasia punctata (CDP) and cervical myelopathy due to kyphosis with os odontoideum underwent anterior and posterior fusion from C2 to T2 with the aim of avoiding occipital fusion. However, occipital fusion was required 9 months after the initial surgery because of dysphagia caused by atlantoaxial subluxation.Conclusion:The surgical strategy for cervical kyphosis with os odontoideum in patients with CDP remains controversial. We attempted to avoid occipital fusion; however, midcervical fusion resulted in instability at the os odontoideum, which necessitated extending the fusion to the occiput.

Purpose: To compare staged, foundation-first (anchor-first) versus single-stage (same-day) traditional growing rod (TGR) implantation for early-onset scoliosis (EOS), with a prespecified focus on severe deformity and/or thoracic hyperkyphosis. Methods: In this single-center cohort study, we performed a retrospective analysis of prospectively collected data from EOS patients treated with TGR. The primary outcome was the proportion of patients with at least one complication requiring unplanned surgery during growing-rod treatment (excluding post-final fusion surgeries). Radiographic outcomes were assessed at early postoperative (PO1mo) and final follow-up. A prespecified severe cohort was defined as preoperative max Cobb > 100° and/or thoracic kyphosis (T2-T12) ≥ 60°. Results: Fifty-four patients were included (same-day n = 39; staged n = 15), including 18 severe-eligible patients (same-day n = 6; staged n = 12). In the overall cohort, complications requiring unplanned surgery were similar between same-day and staged implantation (same-day 33.3% vs. staged 26.7%; RR 0.80; P = 0.751). In the severe cohort, staged implantation was associated with fewer complications requiring unplanned surgery (same-day 83.3% vs. staged 25.0%; RR 0.30; P = 0.043) and fewer total complication events per patient (P = 0.005). Radiographic correction and growth at PO1mo and final follow-up were comparable between strategies in the severe cohort. Conclusion: Staged anchor-first TGR implantation was associated with fewer complications requiring unplanned surgery in the prespecified severe cohort, with comparable radiographic outcomes. These hypothesis-generating findings support further evaluation of staged implantation as a selective strategy for severe EOS in larger multicenter cohorts. Level of evidence: III.

Study Design: Retrospective comparative study. Objectives: To compare the surgical and clinical outcomes of ventral intradural extramedullary (IDEM) schwannomas to those of dorsal/lateral IDEM schwannomas. Setting: The single institution in Japan. Methods: This study included 94 patients with cervical or thoracic IDEM schwannomas who underwent tumor resection via a posterior approach between 2012 and 2022. Patients were categorized into Ventral (n = 12) and Dorsal/Lateral (n = 82) groups based on tumor localization. Demographic and surgical data, including surgical time and intraoperative motor evoked potential (MEP) changes, as well as clinical outcomes such as Japanese Orthopaedic Association (JOA) scores and gait function (modified McCormick scale, MMCS), were evaluated. Results: The Ventral group had a significantly longer surgical time (p = 0.039) and was more likely to experience a temporary decrease in intraoperative MEP waveforms (p = 0.008) compared to the Dorsal/Lateral group. However, there were no significant differences between the groups in age at surgery, sex, level, tumor size, estimated blood loss, JOA score improvement, JOA recovery rate, or gait function at the final follow-up. Gross total resection (GTR) was achieved in all cases. Conclusions: Despite longer surgical times and more likely to experience a temporary decrease in intraoperative MEP waveforms, ventral IDEM schwannomas do not result in significantly worse surgical or clinical outcomes compared to dorsal/lateral IDEM schwannomas. These findings suggest that even if the surgical procedure requires longer, gross total resection of ventral schwannomas via a posterior approach is resulting in favorable treatment outcomes.

Study design: Single-institution retrospective study. Objectives: To assess postoperative functional and quality of life (QOL) outcomes in elderly patients who underwent cervical spinal cord tumor surgery using the Japanese Orthopedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ). Setting: Single university hospital. Methods: This retrospective study included 97 patients who underwent surgery for cervical spinal cord tumors between 2000 and 2016. Patients were divided into two groups: a younger group (patients < 65 years old) and an elderly group (patients ≥ 65 years old). Surgical outcomes were evaluated using JOA scores and JOACMEQ, with statistical comparisons between age (younger vs. elderly) and tumor types (intramedullary vs. extramedullary). Results: Preoperative JOA scores were significantly lower in the elderly group compared to the younger group. Postoperative recovery rates were similar between the two groups. Extramedullary tumor resections in the elderly showed notable functional improvements. Conversely, elderly patients with intramedullary tumors exhibited poorer outcomes in lower extremity function and QOL, as measured by the JOACMEQ. Conclusion: Surgical intervention for cervical spinal cord tumors in elderly patients can yield functional and QOL outcomes similar to those in younger patients, especially for extramedullary tumors. However, intramedullary tumor resections in the elderly may result in less favorable outcomes, particularly in lower limb function and QOL. These findings underscore the importance of thorough preoperative counseling for elderly patients, highlighting potential risks and benefits based on tumor type.

Study design: Retrospective cohort study Objectives: Ventrally located cervical spinal meningiomas present significant surgical challenges due to their proximity to the spinal cord and nerve roots. This study aimed to evaluate the surgical outcomes of these tumors resected via the posterior approach and to compare them with dorsolaterally located meningiomas. Setting: The single institution in Japan. Methods: A retrospective review was conducted on 39 patients who underwent posterior surgical resection of cervical spinal meningiomas between 2008 and 2023, with a minimum follow-up of one year. Patients were classified into ventral (n = 17) and dorsolateral (n = 22) groups based on tumor localization. Neurological function was assessed using the Japanese Orthopedic Association (JOA) score, and surgical outcomes were compared. Results: The groups had no significant differences in operative time or blood loss. However, nerve root resection was significantly more frequent in the ventral group (41.2 vs. 9.1%, p = 0.02), and perioperative complications and intraoperative motor-evoked potential amplitude reduction (35.3 vs. 4.5%, p = 0.03) were more common (41.2 vs. 13.6%, p = 0.06). Although postoperative JOA scores were lower in the ventral group (14.6 ± 0.6 vs. 16.4 ± 0.3, p = 0.01), both groups showed significant postoperative improvement compared to preoperative scores (p < 0.01). Conclusions: Despite the higher risk of nerve root sacrifice and limited neurological recovery associated with the posterior approach, considering the functional improvements from baseline, it remains a viable surgical option for ventrally located cervical meningiomas. Further studies comparing different surgical approaches are needed to optimize treatment strategies.

Study Design. – A retrospective multicenter study. Objectives. – To analyze symptom-specific surgical outcomes in patients with mild degenerative cervical myelopathy (DCM) and identify predictors of postoperative residual symptoms. Summary of Background Data. – DCM is the most common cause of spinal cord impairment in adults. While surgical intervention is recommended for moderate to severe DCM, optimal treatment strategies for mild DCM remain unclear. Previous studies have focused on total Japanese Orthopaedic Association (JOA)/modified JOA (mJOA) score without detailed symptom-specific analyses. Materials and Methods. – We reviewed 679 consecutive patients who underwent surgical decompression with or without fusion for DCM across three institutions in Japan. Among them, 104 patients with mild DCM (JOA score 14.5–16.5) were included. We assessed demographic data, radiographic factors, magnetic resonance imaging parameters, and clinical scores. Symptom-specific analyses were conducted using preoperative and 2-year postoperative JOA scores, and the predictors of persistent symptoms were analyzed using multivariable logistic regression. Results. – The mean maximum canal compromise was 49.7%, and maximum spinal cord compression was 37.2%. The most common factors leading to surgery was symptom deterioration (94.2%). In symptom-specific analysis, 60.9% of patients exhibited persistent upper extremity sensory impairment, significantly higher than other domains. Multivariable analysis identified angular-edged deformity of the spinal cord on axial MRI as an independent predictor of persistent upper extremity sensory impairment (odds ratio: 4.264, 95% CI: 1.312–13.854, P=0.016). Conclusion. – The majority of mild DCM patients who underwent surgery had severe spinal cord compression, with symptom progression serving as the trigger for surgical intervention. While surgical intervention improves overall function, upper extremity sensory impairments frequently persisted postoperatively, even in mild cases. Angular-edged deformity was a significant predictor for postoperative upper extremity sensory deficits, emphasizing the need for careful preoperative evaluation of spinal cord morphology to better inform prognosis and guide treatment decisions in patients with mild DCM. Level of Evidence. – Level 4.

Introduction: The efficacy of minimally invasive surgeries for thoracolumbar flexion-distraction injuries (FDIs) has been reported, but those surgeries were monosegmental fusion surgeries of two adjacent vertebrae with bone grafts or temporary fixations using percutaneous pedicle screws (PPSs) that were at least bisegmental. Our idea was to fuse the fracture itself, not to fuse the fractured vertebra with an adjacent vertebra or to stabilize the fractured vertebra by bridging rostrally/caudally adjacent intact vertebrae, specifically when the displacement is minimal. This study aimed to present the surgical techniques of reduction and temporary monosegmental fixation of neurologically intact thoracolumbar bony FDIs using multiaxial PPSs, which can minimize the surgical invasiveness and preserve all motion segments, as well as report three cases treated with this procedure. Technical Note: When the fracture extended from the vertebral body to the spinous process at the same level, screws were placed into the fractured vertebra rostrally to the fracture along the rostral endplate, and the caudally adjacent vertebra was instrumented beyond the fracture line. When the fracture extended from the vertebral body to the spinous process of the rostrally adjacent vertebra, screws were placed into the fractured vertebra caudally to the fracture line, and the rostrally adjacent vertebra was instrumented. The kyphotic deformity was reduced through ligamentotaxis by using MPPSs in the rostral vertebra as rigid joysticks to apply direct buttress leverage to the rostral endplate. Intraoperative blood loss was minimal. The correction of kyphotic deformity and its durability were acceptable, and the segmental range of motion of the two affected vertebrae from flexion to extension was maintained after implant removal. Conclusions: This surgery can act as the least-invasive option for the management of thoracolumbar bony FDIs to allow early ambulation without external bracing and to preserve all the motion segments.

Study Design: Retrospective Cohort Study. Objective: Modic changes (MCs) have been associated with low back pain; however, their prognostic value in surgical outcomes—particularly in patients with lumbar spinal stenosis (LSS) treated with decompression alone—remains unclear. Few studies have investigated the progression and long-term clinical impact of MCs. This study aimed to evaluate the 10-year progression of MCs and their association with clinical outcomes following posterior decompression surgery for LSS. Methods: This study included 62 patients who underwent posterior decompression for LSS and completed a 10-year follow-up with MRI and clinical assessments. MCs and disc degeneration were evaluated using standardized MRI criteria. Japanese Orthopaedic Association (JOA) scores and recovery rates were assessed preoperatively and at follow-up. Outcomes were compared between Modic-negative patients and those with preoperative Modic Type 1 or Type 2 changes. Analysis of covariance adjusted for confounding variables. Results: The prevalence of MCs increased from 37.1% preoperatively to 74.2% at 10 years. Type 1 changes were dynamic, often progressing to Type 2 or 3. Type 2 changes were more stable and associated with significantly lower postoperative JOA scores and recovery rates compared to Modic-negative or Type 1 patients (P < 0.05), after adjustment for age, sex, sagittal alignment parameters, and disc degeneration. Type 2 MCs were also linked with minimal improvement in back pain. Conclusion: Modic changes, particularly Type 2, are associated with inferior long-term outcomes. These findings suggest that Modic Type 2 may serve as a prognostic marker of advanced degeneration and may be associated with reduced recovery following decompression surgery.

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 χ2 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.

Purpose: Intradural spinal metastases, including intramedullary (IM) and intradural extramedullary (IDEM) lesions, are rare manifestations of advanced systemic malignancy, and the role of surgery remains controversial. This study aimed to clarify how anatomical compartments influence surgical intent, feasibility, and postoperative neurological outcomes. Methods: We retrospectively reviewed fifteen consecutive patients who underwent surgery for intradural spinal metastases between 2010 and 2024. Lesions were classified as IM (n = 6) or IDEM (n = 9). Clinical presentation, operative characteristics, extent of resection, and adjuvant therapy were evaluated. Neurological function was assessed using the modified McCormick scale (MMCS) before and after surgery. Results: IM lesions were more frequently associated with severe preoperative neurological impairment and were predominantly located in the thoracic spine, whereas IDEM lesions were distributed across cervical, thoracic, and lumbar levels. Gross total resection was achieved more often in IDEM lesions (44.4%) than in IM lesions (16.7%). Postoperatively, neurological function improved in 5 patients (33.3%), remained stable in 6 (40.0%), and deteriorated in 4 (26.7%). Although improvement occurred in both groups, IDEM lesions more often achieved a favorable final functional status (MMCS grades I–II), whereas IM lesions frequently showed limited functional recovery. No perioperative complications were observed. Conclusions: Surgical intervention for intradural spinal metastases may be considered selectively as part of a multidisciplinary palliative strategy focused on neurological function. Anatomical compartment influences surgical feasibility, intent, and achievable outcomes. IDEM lesions may allow resection with functional recovery in selected patients, whereas IM lesions generally require a conservative, function-preserving approach with clearly defined goals.

Objective: This study examined radiographic changes in local and global spinal alignments and clinical outcomes following tumor resection without spinal fixation in patients with lumbar dumbbell tumors (LDTs). Methods: We included 28 patients with LDTs who were followed for at least 2 years after surgery. We analyzed variations in the outcome variables by measuring individual coronal and sagittal parameters from radiographs. Clinical outcomes were assessed using the modified McCormick scale, the Japanese Orthopedic Association score, and the visual analog scale. To evaluate the impact of tumor location on these outcomes, we categorized the patients into 3 groups based on tumor location: upper (T12–L1), middle (L2–3), or lower (L4–S1) group. Results: The local and global spinal parameters (including Cobb angle, cervical lordosis, T1 slope, thoracic kyphosis, thoracolumbar kyphosis, lumbar lordosis [global, upper, middle, lower], sacral slope, pelvic incidence, and pelvic tilt) did not show significant changes after surgery. Preoperatively, all patients experienced gait disturbances, but at the final follow-up, nearly all of them (27 cases, 96.4%) could walk without support. The Japanese Orthopedic Association score and visual analog scale demonstrated significant postoperative improvements. There were no statistically significant group differences in postoperative coronal and sagittal profiles or clinical outcomes among the upper, middle, and lower groups. Conclusions: Tumor resection without spinal fixation had no substantial impact on local and global spinal alignments and led to satisfactory clinical outcomes, suggesting that spinal fixation may not always be necessary when resecting LDTs.