Masahiro Inoue

Study Design: Retrospective cohort study.Purpose: To identify whether the presence and features of epidural metastases are risk factors for metastatic spinal cord compression (MSCC).Overview of Literature: Several factors are associated with the development of MSCC in patients with spinal metastases. However, the relationship between epidural metastasis and the development of MSCC is not well understood.Methods: Among patients with spinal metastases at the spinal cord level treated at a single institution from 2017 to 2023, 191 cases (age: 66.4±12.9 years; sex: 120 male patients) were studied. We defined MSCC as a decrease of one or more grades in the American Spinal Injury Association (ASIA) impairment scale due to spinal metastases. Patients were diagnosed with epidural metastasis at the level of spinal metastasis. When the features of epidural metastases could be evaluated, the epidural spinal cord compression (ESCC) scale and circumferential angle of spinal cord compression (CASCC) were assessed. The risk factors for developing MSCC and high-risk epidural metastases were analyzed.Results: Of the patients with spinal metastases who developed MSCC during follow-up, 97.6% had epidural metastases before the onset of MSCC. Multivariate logistic regression analysis identified the presence of epidural metastasis as an independent risk factor for MSCC. In patients with evaluable epidural metastases, multivariate logistic regression analysis identified the ESCC scale and CASCC as high-risk factors. The cutoffs were determined to be 3 for the ESCC scale and 180° for CASCC.Conclusions: Epidural metastasis was identified as a risk factor for MSCC in patients with spinal metastases. Additionally, epidural metastases in those with an ESCC scale of 3 and a CASCC greater than 180° were categorized as high-risk tumors.

Background: MRI T2 mapping provides quantitative information on muscle tissue properties without ionizing radiation. We investigated whether preoperative paravertebral muscle T2 relaxation time was associated with early clinical improvement after decompression for lumbar spinal stenosis.Methods: This retrospective cohort study included 78 consecutive patients who underwent decompression without fusion between April 2020 and April 2024. Preoperative imaging at L4/5 included T2 relaxation times of the paravertebral and psoas major muscles, CT number, CT-derived cross-sectional area, and MRI fat infiltration grade. The primary outcome was improvement in the Japanese Orthopaedic Association (JOA) score at 3 months. Secondary outcomes included improvements in numeric rating scale scores for leg pain and low back pain. Associations were examined using Spearman correlation and multivariable linear regression adjusted for age, sex, the corresponding baseline outcome score, and multilevel decompression. A sensitivity analysis additionally adjusted for whether L4/5 was included in the decompression. Secondary analyses were exploratory.Results: Higher paravertebral muscle T2 relaxation time was associated with less JOA score improvement (Spearman ρ = -0.521; p < 0.001). This association remained after adjustment (regression coefficient per millisecond [β] = -0.130; 95% confidence interval [CI], -0.195 to -0.065; p < 0.001). Additional adjustment for L4/5 inclusion yielded a similar estimate (β = -0.129; 95% CI, -0.201 to -0.056; p < 0.001). In secondary adjusted analyses, higher paravertebral muscle T2 relaxation time was associated with less leg pain improvement (β = -0.050; 95% CI, -0.098 to -0.001; p = 0.047), but not with low back pain improvement (p = 0.357). Higher psoas major T2 relaxation time was also associated with less JOA score improvement in a separate adjusted model (β = -0.109; 95% CI, -0.203 to -0.016; p = 0.023).Conclusions: Preoperative paravertebral muscle T2 relaxation time was associated with 3-month JOA score improvement after lumbar decompression, with a consistent association after adjustment for clinical and surgical factors. T2 mapping may complement preoperative assessment by providing radiation-free quantitative information on muscle condition relevant to early postoperative recovery.

Study Design.: Retrospective single-center cohort study. Objective.: To determine whether baseline modified Lenke classification (MLC), assessed from standing whole-spine radiographs, stratifies brace initiation risk and longitudinal Cobb-angle trajectories in female patients with adolescent idiopathic scoliosis (AIS) before reaching the conventional bracing threshold. Summary of Background Data.: AIS progression is heterogeneous. Baseline Cobb angle and skeletal maturity are established risk factors, but whether simple baseline curve-pattern classification adds risk-stratification information during nonoperative follow-up remains unclear. Methods.: We included female AIS patients aged 10 to P =0.002) and reduced AICc, although BIC increased. At baseline Cobb 20°, adjusted 2-year risk ranged from 23.3% in MLC 1 to 55.9% in MLC 4. Longitudinal Cobb-angle trajectories differed according to MLC. Conclusion.: Baseline MLC may provide complementary information for stratifying brace-initiation risk and longitudinal Cobb-angle trajectories before the conventional bracing threshold.

Symptomatic lumbar disc herniation during pregnancy is rare, and surgery in the prone position during late pregnancy is challenging because of the risk of abdominal and aortocaval compression. A 42-year-old woman at 32 weeks of gestation presented with severe bilateral buttock pain, left radiculopathy, perineal sensory disturbance, and later bladder and bowel dysfunction due to L4-5 lumbar disc herniation. Emergency posterior lumbar discectomy was performed under general anesthesia in the prone position. A four-point support table combined with hammock-style abdominal suspension using elastic bandages and stockinettes allowed abdominal decompression and continuous cardiotocography monitoring. Her leg pain improved after emergence from anesthesia, and fetal status remained stable. She later delivered a healthy boy. Prone-position lumbar surgery may be considered in selected patients during late pregnancy when abdominal compression is avoided, fetal monitoring is maintained, and emergency obstetric intervention is available.

Pyogenic sacroiliitis (PSI) is an uncommon form of septic arthritis and is frequently diagnosed late in older adults because initial symptoms are nonspecific and imaging findings may be misattributed to other sources of infection. We report two older patients with PSI complicated by massive retroperitoneal and gluteal abscesses, highlighting the importance of early recognition and, when indicated, timely surgical source control. Case 1 was an 83‐year‐old woman in whom a conspicuous retroperitoneal abscess and abnormal urinalysis led to suspicion of an intra‐abdominal or urinary tract source, delaying recognition of PSI. Despite antibiotics, she deteriorated with organ dysfunction; re‐evaluation of the initial magnetic resonance imaging MRI identified the sacroiliac joint as the primary focus, and staged surgical drainage procedures were required, followed by a prolonged recovery. Case 2 was a 70‐year‐old woman who presented in septic shock after failing outpatient treatment for presumed lumbar spine disease. Based on the diagnostic pitfalls in Case 1, PSI was immediately suspected; emergency drainage of both retroperitoneal and gluteal collections was performed on the day of presentation, which was followed by rapid stabilization and recovery. These cases emphasize that, in older patients with low back or gluteal pain, the concurrent presence of retroperitoneal and gluteal abscesses should prompt careful evaluation of the sacroiliac joint. These observations suggest that early diagnosis and timely assessment for surgical source control may contribute to favorable outcomes in severe cases.

Kuwabara A, et al. Yonsei Med J. 2026 Sep;67(9):680-685. https://doi.org/10.3349/ymj.2025.0262

Introduction Age-related changes in body composition, particularly sarcopenia and fat accumulation, have been widely studied in older adults, but data on healthy working-age populations remain limited. This study aimed to investigate the associations between exercise habits, dietary intake, and body composition in healthy adults aged 20-59 years. Methods A cross-sectional study was conducted among 1,738 employees undergoing health checkups. Body composition was assessed using bioelectrical impedance analysis (BIA). Exercise frequency and dietary habits were evaluated via questionnaire. Skeletal muscle mass index (SMI) and body fat mass index (BFMI) were calculated, and associations were analyzed by sex. Results SMI remained stable across age groups in men but increased with age in women; BFMI increased with age in both sexes. Regular exercise was significantly associated with higher SMI but not with BFMI. Intake of fish, soy products, and dairy products correlated with higher SMI, while higher fat intake was associated with increased BFMI. Conclusion Exercise habits and protein-rich diets were associated with greater skeletal muscle mass, while fat mass appeared to be more influenced by age and dietary fat intake. Further longitudinal studies are needed to clarify the causal pathways for sarcopenia prevention in working-age populations.

Purpose: The principal objective of this study was to develop and evaluate a deep learning model for segmenting the common iliac vein (CIV) from intraoperative endoscopic videos during oblique lateral interbody fusion for L5/S1 (OLIF51), a minimally invasive surgical procedure for degenerative lumbosacral spine diseases. The study aimed to address the challenge of intraoperative differentiation of the CIV from surrounding tissues to minimize the risk of vascular damage during the surgery. Methods: We employed two convolutional neural network (CNN) architectures: U-Net and U-Net++ with a ResNet18 backbone, for semantic segmentation. Gamma correction was applied during image preprocessing to improve luminance contrast between the CIV and adjacent tissues. We used a dataset of 614 endoscopic images from OLIF51 surgeries for model training, validation, and testing. Results: The U-Net++/ResNet18 model outperformed, achieving a Dice score of 0.70, indicating superior ability in delineating the position and shape of the CIV compared to the U-Net/ResNet18 model, which achieved a Dice score of 0.59. Gamma correction increased the differentiation between the CIV and the artery, improving the Dice score from 0.44 to 0.70. Conclusion: The findings demonstrate that deep learning models, especially the U-Net++ with ResNet18 enhanced by gamma correction preprocessing, can effectively segment the CIV in intraoperative videos. This approach has the potential to significantly improve intraoperative assistance and reduce the risk of vascular injury during OLIF51 procedures, despite the need for further research and refinement of the model for clinical application.

Kuwabara A, et al. Yonsei Med J. 2024 Dec;66:e11. https://doi.org/10.3349/ymj.2023.0535

Introduction Wearable trackers are instrumental in monitoring various health indicators, notably daily physical activity, which is crucial for managing chronic diseases and improving overall health. This study examined the relationship between physical activity levels measured using JINS MEME, an eyeglass-type wearable device equipped with motion sensors, and subjective activity assessments reported through the International Physical Activity Questionnaire (IPAQ). Methods Healthy volunteers aged 20-60 were recruited for an observational study. Participants wore the JINS MEME throughout the day for one week, and data on walking activity were collected and analyzed alongside IPAQ responses to evaluate subjective physical activity levels. The correlation between the two sets of data was evaluated using the nonparametric Spearman’s rho (ρ) correlation coefficient for both the assessed metabolic equivalents (METs) score of the JINS MEME and the IPAQ. Similarly, the relationship between the IPAQ questionnaire items and the measurements from the JINS MEME. Results The study included 42 participants and revealed a strong correlation (R=0.719, P<0.01) between the metabolic equivalents (METs) calculated from the JINS MEME and IPAQ scores, especially for walking activities. Similarly, a significant association was found between the IPAQ data and walking speed (R=0.129, P=0.02). METs showed significant relationships with all physical activities, except sitting or reclining time. Conclusion This study validated the use of eyeglass-type wearable devices, such as the JINS MEME, to accurately assess physical activity levels, demonstrating a strong correlation with subjective assessments using the IPAQ. This highlights the potential of wearable devices in comprehensive health monitoring and management strategies.