Introduction: The mechanisms underlying postural abnormalities in Parkinson's disease (PD) are unclear, and their characteristics are not well characterized. The PD clinical database (DB) was established jointly by the Department of Orthopedics and Department of Neurology at our institution, and we investigated the characteristics of spinal balance and skeletal muscle mass in patients with PD.

Methods: We analyzed 42 of the 426 patients with PD enrolled in the DB at our institution. The investigation items were spinal alignment evaluation using whole spine x-rays and skeletal muscle mass evaluation using whole-body DXA.

Results: The PD duration was 9.1±5.0 years, and the Hoenhn & Yahr classification was as follows: grade I: 1 patient, grade II: 16 patients, grade III: 17 patients, grade IV: 6 patients, and grade V: 2 patients. The spinal alignment of all PD patients showed high C7-CSVL, high C7-SVA, PI-LL mismatch, thoracic hyperkyphosis, elevated T1 slope, and imbalance in the coronal and sagittal planes, with a high percentage of patients with severe imbalance (45.2%). It tended to worsen as the PD progressed. The prevalence of muscle mass sarcopenia was 38.1%, with a high rate of 48.0% in patients with Yahr III or more.

Conclusions: It was suggested that patients with PD tend to have severe coronal and, especially, sagittal and spinal imbalances as the disease severity progresses, and that there is a high prevalence of sarcopenia, which may be involved in postural abnormalities and spinal balance.

Introduction: In high-risk surgeries, those involving pathologies such as ossification of the posterior longitudinal ligament in the spine, spinal cord tumors, and spinal deformities, utilization of intraoperative neurophysiological monitoring (IONM) has been reported to be beneficial. However, efficacy of IONM for lumbosacral spinal surgery remains debated. Therefore, this study aimed to evaluate the efficacy of IONM in lumbosacral spinal surgeries in comparison with its use in cervical and/or thoracic spine surgeries.

Methods: This was a multi-institutional prospective cohort study. The patients underwent spinal surgery with intraoperative neurophysiological monitoring in the hospitals of the Spinal Cord Monitoring Committee of the Japanese Society for Spine Surgery and Related Research. Patients were divided into two groups at the surgical level: 'cervical and/or thoracic' and 'lumbar and/or sacral'. Primary endpoints were sensitivity, specificity, positive and negative predictive values (PPV and NPV), and positive and negative likelihood ratios (PLR and NLR), and secondary endpoints were the incidence of postoperative motor palsy and the cutoff value of the rate of decrease of Tc-MEP amplitude in lumbar and/or sacral surgery.

Results: The number of patients with cervical and/or thoracic surgery were 4,765, and those with lumbar and/or sacral surgery were 1,431. Furthermore, the sensitivity, specificity, PPV, NPV, PLR, and NLR were 77.6, 90.1, 21.1, 99.2, 7.9, and 0.2 in cervical and/or thoracic surgery, and 60.7, 95.9, 23.0, 99.2, 14.8, and 0.4 in lumbar and/or sacral surgery respectively. Specificity and PLR for lumbar and/or sacral surgery were significantly higher. Incidence of postoperative motor palsy was 3.1% (152/4,765) in the cervical and/or thoracic surgery group and 1.9% (27/1,431) in the lumbar and/or sacral surgery group. Cutoff value of the rate of Tc-MEP amplitude was 30%, with a 70% decrease compared to the baseline, and the sensitivity and specificity were 64.7% and 87.5%, respectively. The AUC was 0.69.

Conclusions: Considering the substantially high specificity and PLR observed in lumbar and/or sacral surgeries, IONM can be considered effective within the context of lumbosacral spinal surgery.

Introduction: Although Activities of Daily Living (ADL) disorder is a primary concern in long-range fusion in adult spinal deformity surgery, some patients do not experience it. Herein, we investigated the risk factors associated with the occurrence of ADL disorders after long-range fusion.

Methods: A total of 49 patients who had undergone corrective fusion from the middle and lower thoracic spine to the pelvis for at least 2 years and were eligible for ADL research participated in the study. The survey items were evaluated 2 years after the surgery according to the following 10 categories: putting on and taking off socks, toenail clipping, wiping the buttocks, bathing in a bathtub, turning over, putting on and taking off pants, getting up from a chair, sitting upright, picking up fallen objects, and riding in a car. These categories were rated on a three-point scale (total score out of 20) -possible without (2 points) and with (1 point) difficulty and impossible (0 point) -and divided into two groups: Low (total score of ≤14 points) and High (total score of ≥15 points). Between the two groups, various pre- and post-operative parameters, preoperative hip flexibility, knee flexibility, ability to hold the foot in the supine position, preoperative walking speed, and lower limb muscle strength (quadriceps and gastrocnemius) were evaluated.

Results: After 24 months postoperatively, nail clipping and sitting upright were not possible in approximately 60% of patients, whereas turning over and getting up from a chair were possible for almost all patients, and putting on and taking off socks, bathing in a bathtub, putting on and taking off pants, and wiping the buttocks were possible in 80%-90% of patients. PI, postoperative LL, and pre- and post-operative SS were considerably higher in the Low group. There were no notable differences in PT and PI-LL that indicate the degree of correction. The hip external rotation, foot retention, and knee full flex were substantially low in the Low group. Moreover, the walking speed was considerably slow in the Low group, and the quadriceps muscles were remarkably weak. Multivariate logistic regression analysis detected an inability to hold the foot preoperatively as a factor that scored < 14 points.

Conclusions: The risk factors for ADL disorders include the inability to hold the foot and preoperative reserve capacity-such as lower limb muscle strength and gait speed-suggesting that these factors influence postoperative ADL limitations.

Introduction: The superiority of transforaminal full-endoscopic lumbar discectomy (TELD) has been reported while resecting recurrent herniated discs and avoiding adhesion scars after surgery using a posterior approach. However, limitations associated with TELD during revision surgery for lumbar disk herniation (LDH) remain unclear.

Methods: A total of 131 patients with LDH who underwent TELD in revision surgery at L4-5 level participated in the study. Complete removal of the herniated disc was evaluated using lumbar magnetic resonance imaging performed early following surgery, and the clinical results were evaluated retrospectively. Furthermore, we compared these findings with the clinical outcomes of 420 patients who underwent primary surgery.

Results: Among the reoperated cases, complete removal of the herniated disc was observed in 77.1%, postoperative recurrence was observed in 19.8%, and postoperative reoperation was necessary in 19.8%. Postoperative complications occurred in 9.9% of the patients, and the patient satisfaction rate was 81.7% according to the modified Macnab criteria. Considerable differences in complete removal of the herniated disc, postoperative visual analog scale score for leg pain, postoperative Japanese Orthopaedic Association score, postoperative reoperation rate, postoperative complication rate, and patient satisfaction rate were recognized by comparing reoperation and primary operation cases.

Conclusions: TELD was effective in cases undergoing reoperation for LDH. However, the clinical outcomes of revision surgery were substantially inferior to those after primary surgery. Surgeons must be careful to recognize three important factors associated with TELD while performing revision surgery, including accurate identification of the posterior longitudinal ligament, detachment of adhesions, and the need to obtain sufficient decompression.

Introduction: Postoperative lymphocytopenia (cell counts < 1,000/uL) (PL) with spine surgery and <10% of lymphocyte/white blood cell ratios are effective markers of surgical site infection (SSI). However, we have some cases presenting PL without SSI. Therefore, we investigated PL-related factors, without SSI, at postoperative day 7.

Methods: In total, 329 patients underwent spine surgery, with 9 presenting SSI. Lymphocyte cell counts and lymphocyte/white blood cell ratios (LR) at presurgery and postoperative days 2, 7, and 14 were measured. We investigated PL certainties (cell counts <1,000/uL), cell counts, and LR as SSI markers and calculated the most appropriate preoperative cell counts related to PL without SSI at postoperative day 7 using the receiver operating characteristic curve. Moreover, we evaluated the factors related to the preoperative lower cell counts group among anamneses and comorbidities using SPSS (version 29.0, IBM).

Results: PL and lymphocyte cell counts showed no significant differences without LR between the SSI and non-SSI groups. The number of 1,386 cells is a critical point related to PL at postoperative day 7 (p < 0.001, AUC:0.87), and the lower group of lymphocyte cell counts (< 1,386/uL) presented a significantly lower value than the normal group (lymphocyte cell counts ≥ 1,386/uL) preoperatively during all perioperative times. Preoperative protein, immunosuppressive agents, and nephropathy were lower group-related factors.

Conclusions: The lower group of lymphocyte cell counts presents a low value during perioperative times without SSI, which is related to preoperative malnutrition and comorbidities. Thus, we have to pay attention to lymphocytopenia at postoperative day 7 as an SSI marker owing to presenting that lower group without SSI.

Introduction: Postoperative shoulder imbalance (PSI) significantly affects the quality of life of patients with scoliosis. Several studies report the risk factors for PSI; however, the imaging factors that define T1 tilt and RSH motion are unknown, and there are no reports on the magnitude of change in these factors. Herein, we investigated the factors influencing radiographic shoulder height (RSH) and T1 tilt in patients who underwent scoliosis correction using the vertebral coplanar alignment (VCA) technique.

Methods: In total, 76 patients with Lenke type 1, who underwent posterior spinal fusion using the VCA technique at 11 centers, were included. Correlation coefficients between pre- and post-operative changes in RSH and T1 tilt (ΔRSH and ΔT1 tilt) and changes in other parameters were analyzed.

Results: Flexibility of the proximal thoracic curve (PTC) showed a weak negative correlation with ΔRSH. PTC correction rate revealed a weak negative correlation with ΔT1 tilt from preoperative to 2 years postoperative. Change in the main thoracic apical vertebral translation (ΔMT-AVT) indicated a positive weak correlation with ΔRSH from preoperative to immediate postoperative and ΔT1 tilt immediate postoperative and 2 years postoperative.

Conclusions: PTC flexibility and correction rate are important for achieving good shoulder balance in Lenke type 1 scoliosis. ΔMT-AVT is the defining factor for ΔRSH and ΔT1 tilt and the marker for intraoperative evaluation to adjust shoulder balance.