Ryo Mizukoshi

Background/Objectives: Teriparatide, a recombinant form of parathyroid hormone used for the treatment of osteoporosis, has also been investigated in patients undergoing spinal fusion surgery. The aim of this study was to evaluate the association between perioperative teriparatide use and postoperative complications after spinal fusion surgery through a meta-analysis of randomized controlled trials (RCTs) and observational studies. Methods: Systematic searches were conducted across PubMed, EMBASE, Cochrane Library, and Scopus for RCTs and observational studies that compared surgical outcomes in spinal instrumentation procedures with and without teriparatide. The primary pooled outcome was proximal junctional kyphosis (PJK). Secondary outcomes were radiographic nonunion, mechanical complications, reoperation rate, and incidence of new vertebral fractures. Meta-analyses were performed using Mantel–Haenszel models. Results: A total of 20 studies comprising 2543 patients with degenerative lumbar disease, adult spinal deformity, or osteoporotic vertebral fracture were included. Perioperative teriparatide use was associated with a lower incidence of PJK (Risk Ratio [RR] 0.40, 95% confidence interval [CI] 0.22–0.75, p = 0.004) and radiographic nonunion both on a per-patient basis (RR 0.66, 95% CI 0.47–0.93, p = 0.02) and on a per-level basis (RR 0.55, 95% CI 0.37–0.82, p = 0.004). Although there were no statistically significant differences in mechanical complications (RR 0.75, 95% CI 0.54–1.04, p = 0.08), reoperation rate (RR 0.76, 95% CI 0.53–1.08, p = 0.13), and new vertebral fractures (RR 0.60, 95% CI 0.31–1.17, p = 0.13), these outcomes numerically favored teriparatide. Conclusions: Perioperative teriparatide use was associated with lower rates of PJK and radiographic nonunion after spinal fusion surgery. However, the included studies were heterogeneous, and evidence for mechanical complications, reoperation, and new vertebral fractures remains limited.

Purpose To report a rare case of lumbosacral instability following a right external hemipelvectomy for malignant peripheral nerve sheath tumor (MPNST), successfully treated with rigid sacropelvic fixation using a combination of a unilateral iliac screw and an S2 alar-iliac screw. Methods MPNST is a malignant soft tissue sarcoma with a high recurrence rate and poor prognosis. A 44-year-old woman was diagnosed with MPNST in the right pelvis. Despite multiple courses of chemotherapy, the tumor lesion continued to grow. A right external hemipelvectomy was performed, and histopathological analysis confirmed the diagnosis of spindle cell sarcoma consistent with MPNST. Although the tumor was radically resected, the patient developed severe low back pain due to instability at L5-S1. Results Sacropelvic fixation was performed using a unilateral iliac screw and an S2 alar-iliac screw. Intraoperative computed tomography (CT) navigation and virtual reality (VR) images proved invaluable for preoperative planning and for identifying anatomical landmarks during the surgery. The patient had a favorable outcome, with no recurrence observed six years postoperatively. Conclusion Rigid sacropelvic fixation using a combination of a unilateral iliac screw and an S2 alar-iliac screw was successfully performed for lumbosacral instability following the external hemipelvectomy for MPNST, aided by intraoperative CT navigation and VR imaging technologies. Stable fixation was achieved, with no recurrence of MPNST.

Background/Objectives: PhenoAge utilizes biochemical biomarkers to differentiate mortality risk in persons of the same chronological age. However, the details of the relationship between PhenoAge and lumbar spinal stenosis (LSS) remain unclear. We investigated the association between lumbar spinal stenosis (LSS) and biological age quantified by PhenoAge and PhenoAge acceleration (PhenoAgeAccel), comparing surgically treated patients with age- and BMI-matched controls. Methods: This study included 208 LSS patients who underwent surgery. The patients were categorized into four subgroups based on gender and age (≥70 years) at the time of surgery. Demographic data, blood biomarkers, body composition measurements, and Phenotypic age acceleration (PhenoAgeAccel), which was assessed by calculating the residuals from regressing PhenoAge on chronological age were compared among the groups. We also compared control groups matched for age and body mass index (BMI) for each of the four groups using medical examination data. Results: The mean age was 70.2 ± 9.3 years and the mean PhenoAgeAccel was −5.7 ± 6.5 years in the LSS group. PhenoAgeAccel was significantly lower in the control group (−8.5 ± 3.7 years) than in the LSS group, especially in young male (LSS: −2.9 ± 6.7, Control: −7.0 ± 2.8 years), old male (−4.8 ± 4.4, −6.7 ± 4.0 years), and old female (−6.9 ± 5.9, −10.8 ± 3.2 years) subgroups. In the correlation coefficient between PhenoAgeAccel and BMI, there were weak positive correlations (CC: 0.08–0.31) across all subgroups in the control group, whereas there was a weak negative correlation (CC: −0.29) in the old female subgroup in the LSS group. Conclusions: The impact of LSS on PhenoAgeAccel varied by age and gender, and the adverse effect of LSS could be particularly pronounced in elderly women with low BMIs.

Early detection of ossification of the posterior longitudinal ligament (OPLL) is hampered by the late onset of neurological symptoms, so we built and validated an interpretable machine learning model to identify OPLL during routine health examinations. We retrospectively analyzed 1442 Japanese adults screened between 2020 and 2023, including 432 imaging-confirmed cases, after median imputation, one-hot encoding, Random Forest feature selection that reduced 235 variables to 20, and class-balance correction with SMOTE. Logistic regression, Random Forest, Gradient Boosting, and XGBoost models were tuned using a 5-fold cross-validated grid search, in which a re-estimated logistic regression yielded odds ratios for clinical interpretation. The logistic model achieved 65% accuracy and an AUROC of 0.69 (95% CI 0.66–0.76), matching tree-based models, yet with fewer false-negatives. Advanced age (OR 1.60, 95% CI 1.27–2.00) and elevated CA19-9 (OR 1.24, 95% CI 1.00–1.35) independently increased OPLL odds. This concise, explainable tool could facilitate early recognition of OPLL, reduce unnecessary follow-up, and enable timely preventive interventions in high-volume screening programs.

Background: Although the surgical release of the sternocleidomastoid muscle (SCM) is required for residual congenital muscular torticollis (CMT), the surgical outcomes between bipolar and unipolar SCM release remained unclear. The purpose of the present study was to assess surgical outcomes after bipolar and unipolar release of SCM in adolescent/adult patients with neglected CMT. Methods: Twenty-one consecutive adolescent/adult patients with neglected CMT who underwent surgical treatment were enrolled. Clinical and radiographic outcomes were evaluated at preoperative and final follow-up. Results: The bipolar release of SCM was performed in 3 patients (B group; males, n = 1, females, n = 2) and the unipolar release of SCM in 18 patients (U group; males, n = 6, females, n = 12). The mean age at surgery was 40.0 ± 17.0 years in Group B, and that was 32.3 ± 13.1 years in Group U (p = 0.47). The mean follow-up period was 16.0 ± 5.7 months in Group B and 10.4 ± 7.6 months in Group U (p = 0.22). Cervicomandibular angle correction rates were comparable at 75.4 ± 2.4% for the B group and 73.1 ± 11.7% for the U group (p = 0.62). There was no significant difference in clinical outcome according to the modified Cheng and Tang score between the two groups (p = 0.89). No major complications arose, although one patient exhibited a transient neurological deficit of the greater auricular nerve, and one patient developed a hematoma in the B group. Conclusions: The unipolar SCM release appeared to be a non-inferiority and less invasive procedure, minimizing surgical scars and avoiding potential auricular nerve damage in adolescent/adult patients with neglected CMT.