Introduction: Although severe perioperative complications have been reported after occipitocervical fixation surgery for cervical trauma, no studies have specifically evaluated these complications in patients aged over 80 years. This study aimed to assess perioperative complications following occipitocervical fixation surgery for cervical trauma in patients older than 80 years.

Methods: Among the 1,512 patients with cervical injury treated between 2010 and 2020, 41 patients aged ≥65 years who underwent occipitocervical fixation surgery were enrolled at 77 institutions in Japan. Patients were classified into a young-old group (65-79 years, n=21) and an old-old group (≥80 years, n=20). Demographic and surgical data, diagnosis, comorbidities, and perioperative complications were compared between the two groups.

Results: The young-old group included eight atlas fractures and 16 axis fractures, while the old-old group included seven atlas fractures and 15 axis fractures. Perioperative complications occurred in 11 (52%) cases in the young-old group and in four cases (20%) in the old-old group. Reported complications included delirium, dysphagia, pneumonia, implant failure, worsening neurological pain, respiratory disorder, urinary tract infection, diverticular bleeding, cerebral infarction, deep vein thrombosis, and death.

Conclusions: Although there were several selection biases, including trauma severity and surgical indication, advanced age of over 80 years alone does not necessarily lead to a markedly increased risk of perioperative complications following occipitocervical fixation surgery for traumatic cervical spine injuries.

Level of Evidence: Level III

Introduction: Postoperative neuropathic pain (NeP) is common after surgery for cervical ossification of the posterior longitudinal ligament (cOPLL) and may affect clinical outcomes. The PainDETECT questionnaire (PDQ) is a widely used tool for evaluating NeP, while the Spine PDQ (SPDQ) was developed to improve specificity for spinal disorder-related NeP. This study aimed to evaluate postoperative NeP using PDQ and SPDQ and to examine their associations with clinical scores.

Methods: A total of 234 patients (170 men and 64 women; mean age, 61.9 years) who underwent cOPLL surgery were analyzed and followed for more than 1 year across 13 institutions. NeP was assessed using PDQ (cutoff ≥13) and SPDQ (cutoff ≥0). Clinical outcomes included the Japanese Orthopedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ), the visual analogue scale (VAS), and the EuroQol 5-Dimensions 5-Level (EQ-5D-5L). Correlations between NeP scores and clinical outcomes were evaluated. Patients were stratified into four PDQ/SPDQ-based groups: Zone 1: PDQ−/SPDQ−, Zone 2: PDQ+/SPDQ−, Zone 3: PDQ−/SPDQ+, and Zone 4: PDQ+/SPDQ+, and clinical outcomes were compared among the groups.

Results: PDQ showed significant correlations with all clinical outcomes. SPDQ correlated with VAS, EQ-5D-5L, and the bladder function and quality of life (QOL) domains of JOACMEQ but not with other JOACMEQ domains. The PDQ+ group demonstrated worse scores across all domains than the PDQ− group. The SPDQ+ group had higher VAS scores and lower EQ-5D-5L and JOACMEQ QOL scores than that of the SPDQ− group, with no differences in other JOACMEQ domains. Zone 4 had the poorest prognosis, whereas Zone 3 showed higher VAS scores than Zone 1 but preserved JOACMEQ and EQ-5D-5L scores.

Conclusions: PDQ was associated with detecting pain, functional deterioration, and reduced QOL, while SPDQ reflected pain-related aspects only. Combined PDQ/SPDQ assessment and zone classification may stratify NeP severity and its clinical relevance in patients with postoperative cOPLL.

Introduction: Cervical spinal surgery is performed for various pathologies, including degenerative disease, deformity, trauma, tumor, and infection. However, the surgical approach (anterior vs. posterior) and perioperative safety may vary among regions due to differences in patient characteristics, surgeon experience, and healthcare infrastructure. This study aimed to clarify regional variations in approach selection and perioperative outcomes for cervical surgery in Japan using the nationwide registry of the Japanese Spinal Instrumentation Society Database (JSIS-DB).

Methods: This retrospective observational study included adult patients (≥18 years) registered in the JSIS-DB between February 2018 and March 2022 who underwent cervical anterior or posterior fusion surgery. Occipito–cervical and cervico–thoracic fusion procedures were excluded. Patients were classified into 6 geographic regions. Regional differences in patient demographics, surgical characteristics, perioperative outcomes, surgeon experience, and reoperation rates were analyzed using appropriate statistical methods.

Results: A total of 2,581 patients were analyzed. Significant regional variation was observed in patient characteristics, American Society of Anesthesiologists physical status classification, surgical approach, operative time, estimated blood loss, surgical urgency, length of hospital stay, complication rates, and surgeon and assistant experience levels (all p<0.05). Anterior procedures were more frequently performed in the Kanto and Kyushu regions, whereas posterior approaches predominated in other regions. Importantly, no significant regional difference was observed in reoperation rates (p=0.254). Reoperations were infrequent nationwide (5.9% overall) and were primarily related to mechanical or decompressive issues rather than major complications.

Conclusions: This nationwide registry study demonstrated substantial regional variation in surgical strategies and perioperative complication rates in adult cervical surgery in Japan. Despite these differences, reoperation rates remained consistently low and comparable across regions. These findings indicate that while reoperation rates are uniform, perioperative complication profiles vary geographically. This study provides a comprehensive overview of contemporary cervical fusion practice and highlights the need for further research into the factors driving regional variations.

Introduction: We developed a simplified scoring system (JSSR-DB RC3S) to predict systemic complications after spine surgery using data from the nationwide Japanese Society for Spine Surgery and Related Research Database (JSSR-DB).

Methods: This retrospective cohort study included 8,930 spine surgery cases registered between January and March 2024. The target outcome was systemic complications occurring intraoperatively or within 30 days postoperatively. Candidate preoperative variables were screened using least absolute shrinkage and selection operator logistic regression with 5-fold cross-validation, and the five dominant predictors were used to construct the JSSR-DB RC3S. Integer points were assigned using a zero-start scoring approach, followed by score-based recalibration. Internal validation used out-of-fold predictions from 5-fold cross-validation.

Results: The incidence rate of systemic complications was 1.7% (156/8,930). The five selected predictors were age, performance status, emergency surgery, degenerative disease, and spinal trauma. The final score ranged from 0 to 22 points. Observed incidence rates increased from 0.23% in the low-risk group (0-2 points) to 6.67% in the high-risk group (14-22 points). The model performance was acceptable, with an area under the curve of 0.740, observed-to-expected ratio of 0.997, and Brier score of 0.0167.

Conclusions: The JSSR-DB RC3S is a transparent, clinically interpretable, simplified score for predicting systemic complications after spine surgery, derived from Japanese nationwide registry data. It may support perioperative risk communication in daily practice, and may serve as an introductory implementation of the broader JSSR-DB risk calculator framework.

Introduction: This study aimed to characterize neurological recovery trajectories in patients with cervical spinal cord injury, aged ≥65 years.

Methods: This retrospective multicenter cohort study used registry data from the Japan Association of Spine Surgeons with Ambition. Patients aged ≥65 years with traumatic cervical spinal cord injury and complete International Standards for Neurological Classification of Spinal Cord Injury motor score data at baseline, 6 weeks, and 6 months post-injury, were included (n=222). Neurological assessments included total, upper extremity, and lower extremity motor scores; the American Spinal Injury Association Impairment Scale (AIS) and motor zone of partial preservation. Motor recovery and AIS conversion were analyzed based on baseline and 6-week AIS grades.

Results: Motor recovery occurred predominantly within the first 6 weeks after injury. From baseline to 6 weeks, patients with baseline AIS B and C exhibited significantly greater improvement in total motor score than those with AIS A and D. From 6 weeks to 6 months, measurable recovery persisted in patients with AIS C at 6 weeks, whereas those with AIS A or B demonstrated minimal additional gains. AIS conversion followed a similar pattern: 38.5%, 63.6%, and 82.7% among patients with baseline AIS A, B, and C, respectively, which improved by 6 weeks, whereas conversions beyond 6 weeks were uncommon. Among patients who remained AIS A or B at 6 months, motor zone of partial preservation extension occurred almost exclusively within the first 6 weeks.

Conclusions: In older patients with cervical spinal cord injury, most neurological recovery under routine clinical practice occurs within the first 6 weeks after injury. The magnitude of motor recovery and AIS conversion in this cohort was comparable to outcomes reported in age-unrestricted populations, suggesting that meaningful early neurological recovery can be observed even in older patients and highlighting the importance of early neurological assessment.

Study Design: Retrospective cohort study.

Introduction: HCS involving one-level anterior cervical corpectomy and fusion (1L-ACCF) along with ACDF is an alternative technique to the standard of mACDF for DCM, with limited evidence available on postoperative outcomes. The primary objective is to compare 4-year reoperation risk after hybrid cervical surgery (HCS) versus multilevel anterior cervical discectomy and fusion (mACDF) in degenerative cervical myelopathy (DCM). Secondarily, the study evaluates the association of surgical technique with pseudoarthrosis, oral opioid prescriptions, and postoperative dysphagia.

Methods: Using TriNetX, we identified adults (≥18 years) with DCM who underwent either HCS with 1L-ACCF or ≥4-level mACDF from 2004 to 2020. Patients were grouped by surgery type, and reoperation risk factors were used for propensity matching. The primary outcome was the risk ratio ([RR], 95% confidence interval [CI]) for reoperation; secondary outcomes included RRs for pseudoarthrosis, oral opioid prescriptions, and postoperative dysphagia, as well as the mean number of oral opioid prescriptions.

Results: There were 1,203 patients with DCM per cohort (mean age=56 years) after matching. Within the HCS with 1L-ACCF cohort, compared to the mACDF cohort, there was a statistically significant greater risk of reoperation (10.2% vs 7.6%; RR=1.34 [1.03-1.73]; p=0.0267), yet a significantly lower risk of pseudoarthrosis (22.6% vs 32.3%; RR=0.70 [0.61-0.80]; p<0.001) and dysphagia (12.1% vs 18.8%; RR=0.65 [0.53-0.78]; p<0.001). There was no statistically significant difference in the risk or mean count of oral opioid prescriptions between cohorts (RR=0.96 [0.91-1.01]; 8.4 vs 8.9; p=0.471).

Conclusions: There appears to be a higher risk of reoperation after HCS with 1L-ACCF compared to that with mACDF in adult patients with DCM. However, HCS with 1L-ACCF was associated with a lower risk of pseudoarthrosis and dysphagia as compared to that of mACDF, with no difference in oral opioid prescriptions. Surgeons can consider these tradeoffs in the complex decision-making process when recommending a surgical approach for DCM.

Introduction: Adult spinal deformity (ASD) surgery is highly invasive and carries a substantial risk of postoperative wound complications, particularly in patients with type 2 diabetes mellitus (DM). Perioperative hyperglycemia is a known risk factor for surgical-site infection, but glucose thresholds specific to patients with diabetes and ASD remain unclear.

Methods: We retrospectively reviewed 437 adults who underwent ASD correction between 2010 and 2020, of whom 50 (11.4%) had type 2 DM. Capillary blood glucose was measured at standardized intervals from the day of surgery through postoperative day 3 and at least once daily thereafter until discharge. For each diabetic patient, we calculated an overall mean perioperative glucose value (mean of all in-hospital measurements from postoperative day 0 to discharge) and maximum/mean glucose during postoperative days 0-3. These patient-level indices were compared between patients with and without wound complications, and receiver operating characteristic (ROC) analysis based on overall mean glucose was used to explore thresholds associated with wound morbidity.

Results: Wound complications occurred more often in patients with DM than those without DM (18.0% vs 3.1%, p<0.001). Among the patients with diabetes, overall mean perioperative glucose was higher in the wound-complication group than in the non-wound group (184.8±35.1 vs 156.1±26.6 mg/dL; p=0.020). ROC analysis of overall mean glucose yielded an area under the curve of 0.75 and suggested an exploratory threshold around 185 mg/dL. Patients with diabetes also had higher rates of systemic complications.

Conclusions: Type 2 DM was associated with substantially increased wound morbidity and systemic complications after ASD surgery. Higher overall mean perioperative glucose in patients with diabetes was linked to wound complications, and an exploratory threshold near 185 mg/dL showed moderate discriminatory ability. These findings support the concept that tighter perioperative glycemic control may reduce wound morbidity, although the proposed threshold should be regarded as hypothesis-generating and should be confirmed in larger prospective studies.

Introduction: Prompt and accurate identification of pathogens is essential for effective treatment of pyogenic spondylitis. However, conventional non-surgical methods, such as blood culture and percutaneous needle biopsy, have limited sensitivity and reliability. This multicenter study investigated whether specimen collection during full-endoscopic spine surgery (FESS) is more useful than the conventional diagnostic modalities.

Methods: We retrospectively analyzed data for 53 patients diagnosed with pyogenic spondylitis across three participating institutions between January 2021 and April 2025. Pathogen identification rates were compared between FESS, percutaneous needle biopsy, and blood culture. The patients were stratified into three groups based on duration of pre-procedural antibiotic therapy (0 days, 1-13 days, or ≥14 days) to determine the influence of antibiotic exposure on diagnostic yield. Multivariate analysis was performed to adjust for inflammatory markers and clinical factors.

Results: The overall pathogen identification rate was 79.2%, with Escherichia coli (20.8%) and Staphylococcus aureus (17.0%) being the most frequent isolates. FESS achieved the highest identification rate (59.2%), followed by needle biopsy (45.2%) and blood culture (38.6%). Although detection rates were similar among the three methods in antibiotic-naïve patients, FESS demonstrated a significantly higher detection rate in the 1-13-day antibiotic group than blood culture (87.5% vs 16.7%, p=0.026), whereas the difference between FESS and needle biopsy (57.1%) was not statistically significant. FESS yielded positive results in 15.6% of patients, identifying pathogens despite negative findings on both blood culture and needle biopsy.

Conclusions: FESS enables direct targeted sampling of infected tissues, resulting in pathogen identification rates that are higher than those with conventional diagnostic methods, particularly in patients with short-term antibiotic exposure. Unlike needle biopsy, FESS allows for the retrieval of adequate samples under direct vision. These findings indicate that FESS is a valuable diagnostic tool that complements its therapeutic role, potentially facilitating earlier optimization of antimicrobial therapy.

Introduction: Surgical site infection (SSI) is a serious complication of spinal instrumentation surgery that often necessitates implant removal due to biofilm formation. Implant removal adversely affects postoperative outcomes, making implant retention preferable. Although several risk factors for SSI have been reported, those specifically linked to implant removal in lumbar degenerative disease remain insufficiently examined. The purpose of this study was to examine factors associated with implant removal in patients who developed SSI after spinal instrumentation surgery for lumbar degenerative disease.

Methods: Among 4,743 patients who underwent spinal instrumentation surgery for lumbar degenerative disease between 2013 and 2021 at our institution and affiliated centers, 73 developed SSI. After excluding cases with missing data, 50 patients were retrospectively analyzed. They were categorized into an implant removal group (R group, n=15) and an implant retention group (N group, n=35). Patient characteristics, laboratory findings, surgical factors, and postoperative factors were compared. Univariate and receiver operating characteristic (ROC) analyses were performed to examine factors of implant removal.

Results: The implant removal rate was 30%. Univariate analysis showed associations with the number of previous surgeries at the same level (p=0.004), operative time (p=0.03), interval from surgery to SSI onset (p=0.03), and interval from SSI onset to the first surgical intervention (p=0.03). ROC analysis demonstrated cutoff values of 205 minutes for operative time (area under the curve [AUC]=0.692), 42 days from surgery to SSI onset (AUC=0.702), and 22 days from SSI onset to the first surgical intervention (AUC=0.697).

Conclusions: Implant removal after SSI in lumbar degenerative disease was associated with a history of surgery at the same level, prolonged operative time, and delayed SSI onset. Early surgical intervention after SSI onset was associated with implant retention.

Introduction: Lumbar stabilization using an interspinous process device is a surgical option for lumbar spinal canal stenosis. This study retrospectively evaluated the relationship between preoperative computed tomography (CT) measurements and inserted device size.

Methods: A total of 21 consecutive patients who underwent lumbar stabilization with an interspinous process device (Swift system^®) for one- or two-level lumbar spinal canal stenosis were included. The mean age of the patients was 73.2 years. Surgery involved one level in seven patients and two levels in 14 patients. On preoperative CT images, the interspinous process distance was measured at the posterior line of the bilateral facet joints (basal distance) and at a point 8 mm dorsal (dorsal distance), corresponding to the Swift system^® diameter.

Results: The mean basal and dorsal distances were 6.5±2.1 mm and 5.3±2.4 mm, respectively. In 33 levels (93.5%) with a basal distance ≥4 mm, the device was successfully inserted between the spinous process bases. In the two levels with a basal distance of 2 mm, the device could not be inserted at the base and was placed dorsally. Except for these two cases, the size of the inserted device significantly correlated with the basal distance (p<0.01, r=0.694).

Conclusions: The basal interspinous distance on preoperative CT was useful for predicting the appropriate device size. The device could be inserted between the spinous processes in all cases with a basal distance of ≥4 mm.

Introduction: Type 1 Modic change (MC1) is strongly associated with chronic low back pain, but it is unclear whether its anatomical distribution reflects sport-specific spinal loading in elite athletes.

Methods: We retrospectively reviewed elite athletes with chronic low back pain and magnetic resonance imaging (MRI) -confirmed MC1 who had a history of low back pain for >3 months and concordant pain relief after fluoroscopy-guided discography or selective disc block at the MC1 level. Athletes aged >60 years and those with a history of lumbar surgery, scoliosis >10°, or sagittal translation >4 mm were excluded. Three blinded reviewers classified the dominant spinal movement of each athlete during competition (flexion, extension, right/left lateral bending, or axial loading). The distribution pattern of MC1 (anterior, posterior, right, left, or entire) was determined on short-tau inversion recovery MRI scans. Correspondence was assessed only when all reviewers agreed on the dominant movement.

Results: Eighteen athletes (19 levels) with a mean age of 34.5 years were included. MC1 (63%) was most frequently observed at L5-S1. MC1 was localized anteriorly in 42%, to the right in 26%, to the left in 16%, and involved the entire endplate in 16%. There were no posterior-only lesions. Rater consensus on the dominant movement was obtained for 10 athletes (involved in seven sports). Nine of these 10 athletes (90%) showed correspondence between the dominant movement and the distribution of MC1, including flexion with anterior MC1 and right lateral bending with right-sided MC1.

Conclusions: Sports with a single dominant repetitive spinal movement often showed a match between that movement and the location of MC1. This finding supports a focal, load-related mechanism linking sport-specific spinal loading with MC1 in elite athletes with chronic low back pain.

Introduction: Achieving successful lumbosacral interbody fusion is challenging due to the unique anatomical characteristics of the sacrum. The predominantly cancellous bone and short pedicles limit screw purchase, which frequently leads to S1 screw loosening and pseudarthrosis, resulting in persistent pain and poor outcomes. Therefore, the S1 Dual Outer Diameter (DOD) screw, featuring a dual-zone thread design with greater thread depth and sharper edges proximally and reduced thread depth with blunter edges distally, was developed to maximize screw purchase in cancellous and cortical bones. This study aimed to compare the clinical and radiological outcomes of DOD and conventional pedicle screws in posterior lumbosacral interbody fusion.

Methods: A total of 90 patients (control group, n=51; DOD group, n=39) who underwent lumbosacral fusion (≤2 levels) between 2017 and 2023 were retrospectively reviewed. The outcomes included the Japanese Orthopaedic Association (JOA) score and computed tomography-assessed interbody fusion and S1 screw loosening rates over 2 years.

Results: The DOD group demonstrated a significantly higher early fusion rate at six months than the control group (33.3% vs. 9.8%; p=0.006). This early fusion was associated with a significantly higher 6-month JOA recovery rate in the DOD group (59.2%±26.9% vs. 47.8%±22.6%; p=0.029). No significant difference in overall loosening rates was observed between the two groups (20.5% vs. 35.3%; p=0.12). However, patients with one-level fusions in the DOD group showed a significantly lower loosening rate than those in the control group (5.3% vs. 25.8%; p=0.048). A higher preoperative Oswestry Disability Index score, lower lumbar lordosis, and multi-level fusion were risk factors for loosening, even with DOD screws.

Conclusions: S1 DOD screws were associated with significantly improved early fusion and functional recovery, as assessed by the JOA score, and with a significantly lower loosening rate in one-level fusion. These findings indicate that DOD screws are an effective option for short-segment lumbosacral fusion.

Introduction: To determine the consequences and potential mechanisms of injury to the multifidus muscle associated with surgery using the conventional thoracolumbar posterior approach.

Methods: Patients were categorized into three groups based on the duration of time since their initial thoracolumbar fracture surgery: a 1-year postoperative group, a 2-year postoperative group, and a 3-year postoperative group. All patients required removal of internal fixation between May 2023 and June 2024. For each group, we performed morphometric analysis of the multifidus muscle using digital images, and muscle samples were subjected to histological analysis.

Results: Digital photography indicated a significant temporal reduction in the proportion of muscle within the multifidus muscle, exhibiting a significant change over time (p<0.0001). Hematoxylin and eosin staining of histological samples revealed varying degrees of steatosis in the postoperative multifidus muscles; prolonged intervals following internal fixation surgery were associated with more pronounced fat infiltration. Analysis of the multifidus fibrosis using Masson's staining demonstrated that muscle fibers subjected to paravertebral muscle dissection surgery exhibited a tendency towards fibrosis, which increased over time. Reduced vessel density, defined by CD31 expression, was observed at all follow-up times, and the number of nerve fibers decreased significantly with increasing time post-surgery.

Conclusions: Over time, the multifidus muscle exhibited obvious fibrosis and steatosis following traditional posterior thoracolumbar surgery. Our analyses suggest that the mechanism involved could be related to reduced angiogenesis and denervation.

Study Design: Validation Study.

Introduction: General-purpose large language models (LLMs) have shown substantial improvements since 2023, but their performance in specialized clinical tasks remains inadequately validated. This study aimed to evaluate the performance of the latest general-purpose LLMs as of December 2025 in both knowledge-based and practical tasks, specifically focusing on their utility in literature screening for orthopedic research requiring specialized judgment.

Methods: We evaluated nine of the latest general-purpose LLMs from three major providers (OpenAI: gpt-5/5-mini/5-nano, Google: gemini-2.5-pro/flash/flash-lite, Anthropic: claude-opus-4-5/sonnet-4-5/haiku-4-5) using two approaches: (1) knowledge-based assessment using the MedQA-USMLE (United States Medical Licensing Examination) benchmark (1,273 questions), and (2) practical assessment by replicating the primary screening task from a published orthopedic meta-analysis (384 articles). All evaluations were conducted through an identical automated pipeline using structured output to ensure fair comparison.

Results: Top-tier models achieved accuracy exceeding 0.94 (94%) on MedQA-USMLE (gpt-5: 0.9427 [94.27%], gemini-2.5-pro: 0.9340 [93.40%], claude-opus-4-5: 0.9026 [90.26%]), surpassing prior benchmarks. In the specialized meta-analysis screening task, the highest-tier models achieved performance approaching the agreement between two expert evaluators used as the reference standard (claude-opus-4-5: κ=0.8881, gpt-5: κ=0.8805 vs. inter-evaluator κ=0.8951). Confidence scores from structured output demonstrated trends suggesting utility for implementing quality-controlled two-stage screening.

Conclusions: General-purpose LLMs have achieved high medical reasoning capabilities without medical-specific training. In orthopedic literature screening, the highest-tier models demonstrated performance approaching inter-expert agreement, with confidence metrics showing utility for the implementation of quality-controlled screening workflows. These findings suggest that LLMs may serve as potentially useful tools to reduce expert burden in medical literature screening, although validation was limited to a single orthopedic meta-analysis, and generalizability to other settings requires further investigation.

Introduction: Advances in cancer treatment have improved the prognosis of patients with advanced cancer, and the number of patients with bone metastases is increasing. Early interventions, such as a multidisciplinary approach and a specialized outpatient clinic for bone metastasis (SOCBM), are important to prevent fractures and nerve disorders. However, few studies have directly compared the effectiveness of these measures before and after their initiation. We aimed to analyze the usefulness of SOCBM and its impact on spine surgeons in a larger number of cases.

Methods: We included 70 patients with vertebral metastases of carcinoma who underwent surgical treatment performed by spine surgeons. We divided the patients into two groups: before and after the SOCBM was initiated (pre and post groups), and compared their clinical characteristics and surgical information.

Results: In all patients and in those treated for primary tumors at our hospital, the post group demonstrated a longer period from spine surgeon consultation to surgery than the pre group (p=0.0369 and p=0.0111, respectively). Additionally, the proportion of patients leaving the operating room after 8 pm was significantly lower in the post group (p=0.0471). Multivariate logistic regression analysis revealed that the period from spine surgeon consultation to surgery and leaving the operating room after 8 pm were significantly associated with SOCBM visits (p=0.0118 and p=0.0270, respectively).

Conclusions: SOCBM reduces the burden on spine surgeons by providing a margin before surgery for patients with spinal metastasis and by reducing delays for surgical management.

Introduction: Limited data exist regarding the contraction and relaxation patterns of paraspinal muscles (PSMs) during dynamic tasks like gait in healthy individuals. Our preliminary findings, as a cross-sectional study, suggested the existence of distinct, highly individualized activation patterns of PSMs. This study aimed to classify these patterns and to investigate their relationships with functional mobility parameters.

Methods: A total of 57 healthy volunteers participated in 10-m gait and Timed-Up-and-Go (TUG) tests. Paraspinal electromyography (EMG), tri-axial acceleration, and angular velocity were simultaneously recorded using wireless sensors at the lumbar region. Participants were classified into four distinct types (Types A, B, C, and D) based on the synchronization of PSMs EMG with vertical acceleration and EMG amplitude during gait. Functional parameters were compared using analysis of variance and Dunnett's post hoc tests (vs. Type A). Logistic regression analysis was performed to assess the predictability of Type C.

Results: Type C (n=20), characterized by extremely weak PSMs EMG firing (≤±1300 μV) during gait, showed several functional impairments compared with Type A: significantly longer TUG completion time (p<0.05), and shallower anteroposterior inclination angle and reduced pitch angular velocity during the sit-to-stand transition (both p<0.05). Logistic regression confirmed that Type C could be reliably distinguished from Type A (area under the curve ≤0.973) using a combination of EMG-root mean square (EMG-RMS) and kinematic parameters.

Conclusions: Healthy individuals exhibit characteristic individual differences in PSM activation during walking and rising. The group with extremely weak PSM activation (Type C) showed compromised physical function and altered postural control strategies, suggesting that these neuromuscular patterns may reflect subtle functional variations, potentially acting as preclinical indicators of future functional decline.

Background: Mental disorders, such as schizophrenia and mood disorders, are associated with spine injuries. However, the relationship between mental disorders and short-term outcomes after surgery for spine injury remains unclear. This study aimed to investigate the association between mental disorders and postoperative outcomes in surgical patients with thoracolumbar fractures.

Methods: This retrospective cohort study was performed using a national inpatient database in Japan. Patients who were emergently admitted and underwent spinal fixation surgery for thoracolumbar fractures were categorized into schizophrenia, mood disorder, and control groups. Postoperative outcomes included in-hospital mortality, postoperative complications, and 30-day readmission. Multivariable logistic regression analyses were performed to adjust for patient backgrounds and injury severity.

Results: Among 23,148 patients, 1,243 patients had schizophrenia, 1,192 had mood disorder, and the remaining 20,713 patients were classified into the control group. In-hospital mortality was 1.0%, 0.6%, and 1.3%, postoperative complications occurred in 20.7%, 19.2%, and 18.0%, and readmission within 30 days was observed in 2.3%, 3.1%, and 3.2% of patients in the schizophrenia, mood disorder, and control groups, respectively. Compared to the control group, postoperative complications were more likely to occur in the schizophrenia group (odds ratio [OR], 1.77; 95% confidence interval [CI], 1.52-2.06) and the mood disorders group (OR, 1.50; 95% CI, 1.28-1.74). No significant differences were observed in in-hospital mortality or 30-day readmission.

Conclusions: Mental disorders were associated with postoperative complications in patients with spinal injuries. Careful perioperative management may be necessary for this population.

Introduction: Although robotic-assisted spinal instrumentation enables highly accurate screw placement, mechanical feasibility constraints remain underrecognized. During sacral instrumentation, a collision between the robotic arm and the patient's body may prevent completion of S2 alar–iliac (S2AI) screw placement as planned. Alignment-related factors associated with failure of this procedure have not been clearly defined. The aim of this study was to identify spinopelvic alignment factors associated with mechanical interference during robotic-assisted S2 alar–iliac (S2AI) screw insertion.

Methods: This retrospective observational study included 17 consecutive patients who underwent planned robotic-assisted S2AI screw insertion using the Cirq robotic alignment system (Brainlab) between July 2022 and January 2026. Patients were categorized into a success group (robotic guidance completed as planned) and an interference group (robotic guidance abandoned because of mechanical collision requiring conversion to a conventional technique). Supine spinopelvic parameters, including lumbar lordosis, sacral slope, pelvic tilt, and pelvic incidence, were evaluated preoperatively. Continuous variables were compared between groups using the Mann–Whitney U test.

Results: Robotic guidance was successfully completed in 13 patients (76%) and discontinued because of mechanical interference in 4 (24%). Supine lumbar lordosis was significantly greater in the interference group (median 58.5° vs. 27.6°, p=0.0008). All cases in the interference group demonstrated lumbar lordosis >50°, whereas none in the successful group exceeded this value (p<0.001). Pelvic tilt demonstrated complete separation between groups, with negative values in all interference cases and positive values in all successful cases (p=0.0008). Sacral slope was significantly higher in the interference group (p=0.0055), whereas pelvic incidence and skin–to–bone distance were not associated with interference.

Conclusions: Mechanical interference during robotic-assisted S2AI screw insertion was associated with a sagittal alignment profile characterized by increased lumbar lordosis and anterior pelvic orientation. Recognition of alignment-dependent spatial constraints may improve preoperative assessment and help predict technical difficulty.

Introduction: Severely migrated lumbar disc herniations are challenging to access using conventional interlaminar or transforaminal approaches, especially in revision cases. A transpedicular route provides direct access but raises concerns regarding accuracy, safety, and radiation exposure when fluoroscopy is required. In this Technical Note, we describe a transpedicular unilateral biportal endoscopic (UBE) approach assisted by a compact navigation system for a caudally migrated disc herniation, highlighting its feasibility and potential advantages.

Technical Note: A 73-year-old man with a history of L1/2 fusion and multilevel laminoplasty presented with severe low back pain, radicular leg pain, and weakness. Magnetic resonance imaging demonstrated a left L2/3 disc herniation that had migrated caudally to the lower border of the L3 pedicle. Based on these findings, a transpedicular UBE approach assisted by a compact navigation system was selected. After intraoperative computed tomography (CT) acquisition and automatic registration, real-time navigation accurately localized the left L3 pedicle and displayed the planned entry point and drilling trajectory relative to the patient's anatomy. Using a navigated drill, a pedicle entry point was created, and the transpedicular channel was prepared. Under UBE visualization, the medial pedicle wall was drilled to expose the L3 nerve root, enabling direct removal of the caudally migrated fragment. The procedure was completed safely with minimal blood loss and required only a single intraoperative CT, with no fluoroscopy. Postoperative CT confirmed an approximately 6-mm transpedicular bone window without pedicle fracture. The patient had immediate symptom relief and remained recurrence-free at 6 months.

Conclusions: This Technical Note demonstrates the feasibility of a transpedicular UBE approach assisted by compact navigation for complete removal of a severely caudally migrated lumbar disc herniation. The technique allowed accurate instrument guidance, effective decompression, and zero radiation exposure to the surgical team. Future studies are warranted to validate its long-term safety and broader applicability.