論文

Background: Human induced pluripotent stem cell-derived neural stem/progenitor cell (hiPSC-NS/PC)-based cell transplantation has emerged as a groundbreaking method for replacing damaged neural cells and stimulating functional recovery, but its efficacy is strongly influenced by the state of the injured spinal microenvironment. This study evaluates the impact of a dual therapeutic intervention utilizing hepatocyte growth factor (HGF) and hiPSC-NS/PC transplantation on motor function restoration following spinal cord injury (SCI). Methods: Severe contusive SCI was induced in immunocompromised rats, followed by continuous administration of recombinant human HGF protein into the subarachnoid space immediately after SCI for two weeks. Acute-phase histological and RNA sequencing analyses were conducted. Nine days after the injury, hiPSC-NS/PCs were transplanted into the lesion epicenter of the injured spinal cord, and the functional and histological outcomes were determined. Results: The acute-phase HGF-treated group exhibited vascularization, diverse anti-inflammatory effects, and activation of endogenous neural stem cells after SCI, which collectively contributed to tissue preservation. Following cell transplantation into a favorable environment, the transplanted NS/PCs survived well, facilitating remyelination and neuronal regeneration in host tissues. These comprehensive effects led to substantial enhancements in motor function in the dual-therapy group compared to the single-treatment groups. Conclusions: We demonstrate that the combined therapeutic approach of HGF preconditioning and hiPSC-NS/PC transplantation enhances locomotor functional recovery post-SCI, highlighting a highly promising therapeutic strategy for acute to subacute SCI.

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.

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.

The transplantation of neural stem/progenitor cells (NS/PCs) derived from human induced pluripotent stem cells (hiPSCs) has shown promise in spinal cord injury (SCI) model animals. Establishing a functional synaptic connection between the transplanted and host neurons is crucial for motor function recovery. To boost therapeutic outcomes, we developed an ex vivo gene therapy aimed at promoting synapse formation by expressing the synthetic excitatory synapse organizer CPTX in hiPSC-NS/PCs. Using an immunocompromised transgenic rat model of SCI, we evaluated the effects of transplanting CPTX-expressing hiPSC-NS/PCs using histological and functional analyses. Our findings revealed a significant increase in excitatory synapse formation at the transplantation site. Retrograde monosynaptic tracing indicated extensive integration of transplanted neurons into the surrounding neuronal tracts facilitated by CPTX. Consequently, locomotion and spinal cord conduction significantly improved. Thus, ex vivo gene therapy targeting synapse formation holds promise for future clinical applications and offers potential benefits to individuals with SCI.

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. – Prospective multicenter cohort study. Objective. – To comprehensively evaluate the impact of diabetes mellitus (DM) on surgical outcomes, perioperative complications, and patient-reported outcomes in patients undergoing surgery for degenerative cervical myelopathy (DCM). Summary of Background Data. – Both DM and DCM are age-related conditions, and their coexistence has become increasingly common with the aging population. DM is associated with microvascular and metabolic disturbances that may impair neurological recovery and wound healing. Previous studies have yielded inconsistent results, largely due to small sample sizes, retrospective designs, and inadequate adjustment for confounders. Methods. – A total of 875 patients with DCM, including 200 with DM, were prospectively enrolled across ten high volume centers in Japan. Clinical outcomes, including the JOA score, SF 36, Neuropathic Pain Symptom Inventory, and JOA Cervical Myelopathy Evaluation Questionnaire, were evaluated before surgery and at two years after surgery. Perioperative complications were recorded within 30 days after surgery. Clinical and surgical outcomes were analyzed using multivariable statistical models adjusting for demographic and surgical confounders, and the association between preoperative HbA1c and outcomes was examined within the diabetic cohort. Results. – Patients with DM were older and had higher BMI than those without DM. After statistical adjustment, DM was not associated with significant differences in postoperative neurological recovery, quality of life, pain, or perioperative complications. Within the diabetic cohort, higher HbA1c levels were modestly associated with smaller improvements in JOA scores (β=−0.111, P=0.045), but no significant correlations were found with other outcomes or complication rates. Conclusion. – DM did not adversely affect surgical or patient-reported outcomes in patients with DCM when perioperative glycemic control was appropriately maintained. These findings suggest that well-managed DM should not be considered a contraindication to surgical treatment for DCM and provide reassurance for clinicians and patients in shared decision-making.

Study Design: Single-institution retrospective study. Objective: To assess the impact of growing rods (GRs) on postoperative cervical sagittal alignment in patients with early-onset scoliosis (EOS). Summary of Background Data: Cervical sagittal malalignment is associated with neck and cervical spine dysfunction. The impact of surgery for adolescent idiopathic scoliosis on postoperative changes in cervical spine alignment has been reported by studies. Nevertheless, research on sagittal and spinopelvic parameters in patients with EOS is limited. Methods: In this study, 28 patients who underwent GR and were followed up until final fusion or bone maturity were included. Standing whole-spine radiographs obtained before GR, after the initial GR surgery, and at the final follow-up were utilized to measure the radiographic parameters. Patients with one or more of the previously reported poor prognostic factors were included in the cervical malalignment (CM) group (n=13), and those with none of the factors were included in the non-CM group (n=15) at the final follow-up, which was followed by correlation analysis and multivariate logistic regression analysis. Results: No significant change in sagittal alignment between preoperative and final follow-up measurements was found. Pearson correlation analysis revealed a significant positive correlation between the change in the C2-7 angle and T1 slope (T1S) or thoracic kyphosis and a negative correlation between the change in the C2-7 angle and T1S minus C2-7 angle (T1S−CL). The percentage of patients in the CM group increased from 25% preoperatively to 46% at the final follow-up but without significant change. The CM group had significantly smaller preoperative C2-7 angles and lumbar lordosis (LL) and larger T1S−CL and pelvic incidence minus LL (PI−LL) values than the non-CM group. Conclusion: Smaller preoperative C2-7 angles and larger T1S−CL values were identified as risk factors for CM. Postoperative CM is more likely to occur in patients with reduced compensatory function to maintain preoperative cervical kyphosis.

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.

Study Design: Prospective multicenter cohort study. Objectives: To investigate how surgeon experience influences surgical, radiologic outcomes, and patient-reported outcomes (PROMs) after posterior decompression in patients with degenerative cervical myelopathy (DCM). Setting: The multiple institutions in Japan. Methods: We prospectively enrolled 775 patients with DCM who underwent posterior decompression at 10 academic institutions in Japan. Surgeries were performed by either board-certified spine (BCS) surgeons or non-BCS (NBCS) surgeons under direct BCS supervision. Outcomes included surgical parameters, radiographic findings, physician-reported measures, and PROMs, such as the JOA score, Visual Analog Scale (VAS) for pain, JOACMEQ, and SF-36 scores, assessed preoperatively and at 2 years follow-up. Results: Baseline demographics were comparable between groups, except for a higher prevalence of diabetes in the BCS group (p = 0.044). The NBCS group had longer surgical duration (91.1 ± 33.1 minutes vs. 109.4 ± 51.8 minutes, p < 0.001) and greater blood loss (33.7 ± 56.3 mL vs. 45.9 ± 79.4 mL, p = 0.018), despite fewer operated laminae (4.1 ± 1.1 vs. 3.8 ± 1.2, p < 0.001). Perioperative complication rates and radiographic outcomes at 2 years were similar between groups. Both groups showed significant improvements in JOA scores, VAS, all JOACMEQ domains, and most SF-36 subscales, with no significant differences between groups. Conclusion: Posterior decompression for DCM can achieve favorable results when performed by NBCS surgeons under BCS supervision, with outcomes equivalent to those of BCS surgeons. These findings support the safety and educational value of supervised training in spine surgery.

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.

Study Design: Retrospective cohort study. Objective: This study aimed to determine whether the outcomes of posterior correction and fusion surgery (PSF) in patients with residual adolescent idiopathic scoliosis (AIS) during adulthood (Lenke type 5 AdIS) are inferior to those in patients with AIS treated during adolescence. Methods: We retrospectively evaluated 48 patients with type 5 AdIS who underwent PSF after 20 years old. As controls, we selected 67 patients with type 5 AIS who underwent PSF before 18 years old. Both groups were matched based on the preoperative thoracic and thoracolumbar/lumbar Cobb angles, resulting in 33 patients in each group. We compared preoperative and postoperative radiographic parameters and SRS-22 scores between the 2 groups. Results: Preoperatively, the AdIS group had significantly lower flexibility index (59.0% ± 13.0% vs 66.6% ± 16.7%; P = 0.01). The preoperative SRS-22 scores for pain and mental health domain were significantly worse in the AdIS group (pain, 3.9 ± 0.8 vs 4.3 ± 0.7, P < 0.01; mental health, 3.6 ± 0.8 vs 4.2 ± 0.6, P < 0.01). The AdIS group had significantly more fused vertebrae and longer intraoperative time than the AIS group. Postoperatively, lumber Cobb angle (16.1° ± 5.6° vs 8.6° ± 4.0°, P < 0.01) and correction rate were both less favorable in the AdIS group. Both pain and mental health scores remained significantly worse in the AdIS group (pain: AdIS, 4.3 ± 0.6 vs AIS, 4.7 ± 0.3; P < 0.01; mental health: AdIS, 4.1 ± 0.7 vs AIS, 4.5 ± 0.5; P = 0.02). Conclusion: Patients with type 5 AdIS had a similar correction of the major curve as those with AIS; however, the surgery was more invasive, with inferior postoperative clinical outcomes, than those with AIS. These findings suggest that the surgical timing should be carefully considered in patients with type 5 AIS to optimize outcomes.

Study Design. – Multicenter prospective cohort study. Objective. – To evaluate the influence of preoperative mental health status on clinical outcomes following surgery for degenerative cervical myelopathy (DCM). Summary of Background Data. – Surgical treatment for DCM is known to improve neurological function and relieve symptoms. However, the impact of preoperative mental health on postoperative changes in pain, function, and quality of life (QOL) remains unclear. Materials and Methods. – A total of 759 patients who underwent surgery for DCM at 10 institutions were prospectively enrolled and stratified into two groups based on preoperative 36-Item Short-Form Health Survey (SF-36) Mental Component Summary (MCS) scores: lower MCS (<50; n=339) and higher MCS (≥50; n=420). Demographic, surgical, and radiographic data, along with clinical outcomes, were compared between groups. Outcome measures included the Japanese Orthopaedic Association (JOA) score, visual analog scale (VAS), JOA Cervical Myelopathy Evaluation Questionnaire, SF-36, and Neuropathic Pain Symptom Inventory. Results. – Baseline demographics and surgical characteristics were similar; however, psychiatric disorders (4.7% vs. 1.2%, P=0.003) and diabetes (26.0% vs. 19.8%, P=0.042) were more prevalent in the lower MCS group. Neurological recovery was comparable (ΔJOA: 3.0 vs. 2.9, P=0.948). However, the lower MCS group demonstrated significantly greater improvement in neck pain (ΔVAS: –10.4 vs. –4.7, P=0.016), vitality (15.0 vs. 0.7, P<0.001), mental health (15.9 vs. 2.3, P<0.001), and burning pain (–0.5 vs. –0.3, P=0.014). Preoperative MCS was not associated with ΔJOA or recovery rate, but positively correlated with changes in SF-36 mental domains and negatively with burning pain. Conclusions. – Preoperative mental health status does not impact neurological improvement but significantly affects recovery in pain and QOL. These findings suggest that evaluating patients’ psychological well-being before surgery could enhance perioperative planning and support more accurate prognostic counseling. Level of Evidence. – Level II.

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. Level of evidence IV.

Study design: Prospective multicenter cohort study. Objectives: To evaluate the association of smoking status and cumulative smoking exposure with postoperative neurological outcomes in patients undergoing surgery for degenerative cervical myelopathy (DCM). Setting: Multiple institutions in Japan. Methods: A total of 935 patients with DCM were categorized as non-, past-, or current-smokers. Demographic characteristics, operative variables, and postoperative outcomes, including the Japanese Orthopaedic Association (JOA) score and recovery rate, JOA Cervical Myelopathy Evaluation Questionnaire (JOACMEQ), Short Form-36, visual analog scale, and Neuropathic Pain Symptom Inventory, were evaluated over a 2-year follow-up. Postoperative outcomes were analyzed across smoking categories using general linear models. Among current-smokers, cumulative smoking exposure was quantified using the Brinkman index and examined in relation to postoperative outcomes. Results: Differences in postoperative functional outcomes, including the JOA recovery rate and JOACMEQ upper and lower extremity functions, were observed across smoking categories. In contrast, neurological recovery, health-related quality-of-life measures, pain intensity, and overall neuropathic pain scores were generally comparable between the groups. Among current-smokers, cumulative smoking exposure did not demonstrate a clear association with neurological or functional outcomes; however, exploratory analyses identified differences in improvement in specific neuropathic sensory symptoms. Conclusion: Smoking status was associated with differences in postoperative functional recovery after DCM surgery. In contrast, cumulative smoking exposure among current-smokers showed exploratory associations with specific neuropathic sensory outcomes but not with overall neurological or functional recovery. These findings suggest that smoking status and cumulative exposure may influence different outcome domains, supporting smoking cessation as part of preoperative patient management.

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.

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.

BACKGROUND CONTEXT: Health-related quality of life (HRQoL) is a key outcome in degenerative cervical myelopathy (DCM), however, conventional score-based analyses do not capture the complex interdependencies among HRQoL domains or how these relationships change following surgery. PURPOSE: To characterize the structural organization of HRQoL in patients with DCM using a network-based approach. STUDY DESIGN/SETTING: Prospective multicenter observational study. PATIENT SAMPLE: A total of 849 patients undergoing surgical treatment for DCM at 10 high-volume spine centers in Japan. OUTCOME MEASURES: HRQoL was assessed using the Short Form-36 (SF-36), including 8 domain scores and summary component scores, measured at baseline, 1 to 2 years postoperatively. METHODS: Gaussian graphical models were used to construct item-level and domain-level HRQoL networks from preoperative and postoperative SF-36 data. Network comparison tests assessed changes in network structure, global strength, and individual edge weights following surgery. Centrality was quantified using strength and expected influence. Subgroup analyses were performed based on postoperative Japanese Orthopaedic Association (JOA) score responsiveness. RESULTS: Network structure differed significantly between preoperative and postoperative phases at the domain level, whereas global network strength remained unchanged, indicating a reconfiguration of HRQoL relationships rather than uniform strengthening. Role physical (RP) emerged as the most central domain preoperatively and demonstrated a further increase in centrality after surgery. In both subgroups, RP remained highly central after surgery, whereas nonresponders additionally exhibited an increase in the centrality of general health. CONCLUSIONS: Surgical treatment for DCM is associated with a reorganization of the HRQoL network structure rather than a global increase in connectivity. The increasing centrality of RP highlights its potential role in postoperative HRQoL recovery. Network analysis provides a novel framework for understanding HRQoL in DCM and underscores the importance of postoperative strategies aimed at restoring daily role functioning to maximize patient-centered outcomes.

Background: Degenerative cervical spine disorders, including cervical spondylotic myelopathy (CSM), ossification of the posterior longitudinal ligament (OPLL), and cervical disc herniation (CDH), are common surgical indications in aging populations. OPLL is more prevalent in East Asians, likely due to genetic and metabolic factors, yet large-scale prospective data from Asia remain limited. Objective: To characterize diagnosis-specific and age-related clinical features in Japanese patients undergoing cervical spine surgery for degenerative conditions, with a focus on frailty, body mass index (BMI), and neurological status. Methods: This prospective multicenter study enrolled 1482 patients undergoing surgery for degenerative, non-traumatic cervical spine disorders at 10 Japanese institutions between 2019 and 2022. Diagnoses included CSM, OPLL, CDH, cervical radiculopathy (CSR), cervical spondylotic amyotrophy (CSA), and atlantoaxial instability (AAI). Baseline variables included age, sex, BMI, comorbidities, and Japanese Orthopaedic Association (JOA) score. Frailty was assessed using the 11-item modified frailty index (mFI-11), with scores ≥0.27 indicating frailty. Statistical comparisons used ANOVA and chi-square tests. Results: CSM was the most frequent diagnosis (58.7%), followed by OPLL (15.9%) and CDH (14.6%). CDH patients were younger (mean age 53.3), while CSM and AAI predominated in older age groups. Frailty increased with age, from 2.7% in patients aged 40–59 to 30.5% in those ≥80 years. OPLL patients had the highest BMI (26.3 kg/m2) and diabetes prevalence (22.1%). CSM patients showed the lowest mean JOA scores (9.6). Conclusion: This large cohort reveals distinct age- and diagnosis-specific patterns in cervical spine surgery, underscoring the importance of frailty-aware.

Study Design. A retrospective comparative study. Objective. The purpose of this study is to evaluate the relationship between pelvic incidence (PI) and proximal junctional kyphosis (PJK) in patients with Lenke type 5 adolescent idiopathic scoliosis (AIS). Background. 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. Materials and 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 was 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.