藤田 順之

PURPOSE: Retro-odontoid pseudotumor (ROP) is a condition characterized by benign soft tissue proliferation at the odontoid process due to mechanical stress in the atlantoaxial joint, often represented by atlantoaxial subluxation (AAS). However, the pathogenesis of ROP remains unclear, as AAS can also occur without ROP. The purpose of this study is to clarify the pathogenesis of ROP in patients with AAS by analyzing imaging findings in patients without rheumatoid arthritis who underwent surgery for AAS and/or ROP. METHODS: A multicenter cross-sectional study was conducted. Patients without rheumatoid arthritis who underwent surgery for AAS and/or ROP at three university hospitals between 2010 and 2022 were enrolled in this study. Patients were divided into two groups: the ROP group, comprising patients with AAS and ROP, and the non-ROP group, comprising those with AAS without ROP. Patient demographics and preoperative imaging findings, including plain radiography, multidetector computed tomography, and magnetic resonance imaging, were compared between the two groups. RESULTS: The ROP group included 32 patients (age: 75.6 ± 7.7 years; 23 male and 9 female patients), while the non-ROP group comprised 18 patients (age: 70.5 ± 14.6 years; 9 male and 9 female patients). No significant differences were observed between the two groups in terms of age, sex, or history of cervical spine surgery. However, the O-C2 angle in the extension position and C2-C7 sagittal vertical axis were significantly larger in the ROP group than in the non-ROP group. Additionally, degeneration of the facet joints and intervertebral discs in the subaxial cervical spine was significantly more advanced in the ROP group than in the non-ROP group. CONCLUSION: In patients with AAS, the anterior translation of the cervical spine, as well as the progressive degeneration of the subaxial cervical facet joints and intervertebral discs, may increase mechanical stress on the atlantoaxial joint, contributing to the development of ROP.

PURPOSE: Low back pain (LBP) is a common occupational health problem. Chronotype, an individual's preferred timing of activity and sleep, has been linked to pain perception. Previous studies have found a potential association between chronotype and LBP, although the findings were limited by small sample sizes and restricted population types. We investigated the association between evening chronotype (eveningness) and LBP in a cohort comprising public servants of various ages. METHODS: We conducted a cross-sectional analysis of 4728 full-time public servants in Japan. LBP was assessed using a self-reported question. Individuals' chronotypes were determined using the reduced Morningness-Eveningness Questionnaire. The association between chronotype and LBP was analyzed using the chi-squared test and multiple logistic regression models adjusted for age, sex, occupation, overtime work, use of the internet/email, body mass index, smoking status, exercise habits, sedentary behavior, sleep duration, sleep medication use, and depressive symptoms. RESULTS: In total, 30% of the subjects reported LBP. The most common chronotype was intermediate type (51%), followed by morningness (38%) and eveningness (11%). A significant association between eveningness and LBP was observed. After adjusting for potential confounders, individuals with eveningness had a higher prevalence of LBP than those with morningness (36.2% vs. 28.7%; odds ratio: 1.46; 95% confidence interval: 1.16-1.83). CONCLUSION: Eveningness was statistically associated with LBP in a cohort of public servants. The present findings would strengthen the association's generalizability to more varied populations.

BACKGROUND: Hip fractures represent a significant public health issue in an aging society. Early surgical intervention for hip fractures in older adults is associated with fewer complications and higher survival rates, and recent reimbursement incentives in Japan have aimed to encourage surgery within 48 h of injury. However, information on the determinants of delayed surgery, including reimbursement incentives, remains limited. This study aimed to investigate the number of days from admission to surgery and identify factors associated with delayed surgery using data from two acute care hospitals in Japan. METHODS: We retrospectively analyzed data from 1,209 patients aged ≥ 65 years who underwent hip fracture surgery at two hospitals in Japan between April 2021 and March 2024. Patient- and healthcare system-related factors were compared between patients who underwent surgery within 2 days of admission (E group) and those who underwent surgery at later times (L group). Poisson regression was used to identify independent factors associated with delayed surgery. RESULTS: In total, 56% of patients underwent surgery within 2 days of admission. Multivariable analysis identified age ≥ 85 years (prevalence ratio [PR] = 0.81) and trochanteric fracture (PR = 0.81) as factors that reduced the prevalence of delayed surgery. Conversely, diabetes (PR = 1.18); cardiovascular disease (PR = 1.19); low serum albumin levels (PR = 2.08); admission in the pandemic period (PR = 1.26), university hospital (PR = 1.24); and admission on Thursday (PR = 1.69), Friday (PR = 2.99), or Saturday (PR = 2.60) were associated with delayed surgery. The in-hospital mortality rate was approximately 2%, with no significant difference observed between the E and L groups. CONCLUSIONS: Both patient- and healthcare system–related factors were associated with delayed surgery for hip fractures in older adults. Although a reimbursement incentive has been introduced to promote early surgery, real-world challenges, including preoperative risk factors and hospital resources, continue to affect surgical timing. These findings could help inform strategies to enhance timely surgical care for older patients with hip fractures in aging societies.

BACKGROUND: Patient satisfaction is an essential metric for evaluating treatment outcomes for LSS, both for patients and for their primary physicians. However, the Zurich Claudication Questionnaire (ZCQ) is the only representative patient-reported outcome measure that evaluates satisfaction. To develop a model using machine learning to predict postoperative satisfaction among older patients with lumbar spinal stenosis (LSS) based on preoperative and postoperative scores of the Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ). METHODS: The training dataset was composed of time-course data of ZCQ and JOABPEQ scores from patients aged ≥65 years who underwent LSS surgery at a university hospital. The validation dataset included data from patients with LSS treated at a private orthopedic clinic. A linear support vector machine classifier was trained to predict achievement of a "Satisfied" state from preoperative and postoperative JOABPEQ scores. Internal validation was carried out via leave-one-out cross-validation, and external validation using a separate dataset to assess the accuracy, sensitivity, specificity, F1 score, and area under the receiver operating characteristics curve (AUROC). Variable importance was analyzed using model class reliance. RESULTS: A total of 232 and 66 individuals were included in the training and validation datasets, respectively. The machine-learning model exhibited an accuracy of 0.72, sensitivity of 0.75, specificity of 0.69, and AUROC of 0.82. Psychological disorder and walking ability were identified through permutation importance analysis as key factors for satisfaction. External validation on an independent dataset demonstrated comparable accuracy (0.76), sensitivity (0.83), and AUROC (0.75), although the specificity decreased (0.42). CONCLUSIONS: The machine learning model presented here can predict the postoperative satisfaction score on the ZCQ from preoperative and postoperative JOABPEQ scores, highlighting its potential for broader application in clinical settings.

BACKGROUND: Surgical outcomes for lumbar spinal stenosis (LSS) are generally favorable, even in older adults, and they effectively address locomotive syndrome. In older patients with LSS, support from family members during the postoperative recovery period is expected to be helpful, but the extent to which family structure influences surgical outcomes for LSS remains unclear. Herein, this study aimed to investigate the involvement of family structure in surgical outcomes for older patients with LSS. METHODS: This retrospective study included 350 consecutive patients aged ≥65 years who underwent LSS surgery between April 2020 and December 2023. Patients were categorized by family structure into the M (living with multiple family members) or S group (living with few or no family members). Postoperative outcomes were assessed using patient-reported outcomes, including the Roland-Morris Disability Questionnaire (RDQ), Geriatric Locomotive Function Scale (GLFS-25), and Japanese Orthopaedic Association Back Pain Evaluation Questionnaire. RESULTS: The M group consisted of 102 participants, while the S group comprised 248 participants. Preoperatively, there were no significant differences in the scores of all patient-reported outcomes between the groups. However, even after adjusting for baseline characteristics that significantly differed between the groups, the RDQ (p = 0.018) and GLFS-25 scores (p = 0.030) were significantly better in the M group than in the S group at 1 year postoperatively. Furthermore, the proportion of patients with postoperative improvement in the locomotive syndrome stage was significantly higher in the M group than in the S group at both 6 months (p = 0.027) and 1 year (p = 0.002) postoperatively. CONCLUSIONS: Family structure significantly affected postoperative outcomes in older adults with LSS, particularly concerning locomotive syndrome recovery. These findings highlight the potential value of involving families in healthcare planning, while recognizing that the availability and quality of support may vary across households.