Objective: This multicenter study aimed to evaluate the impact of paravertebral muscles (PVMs) degeneration, particularly fat infiltration, on preoperative sagittal imbalance, and postoperative complications and sagittal alignment change in patients with adult spinal deformity (ASD). Methods: A retrospective analysis was conducted on 454 patients who underwent ASD surgery across 5 institutions. Patients were classified into 2 groups based on paraspinal muscle fat infiltration on MRI: those with significant infiltration (FI-PVM(+)) and those with minimal or no infiltration (FI-PVM(-)). Propensity score matching was performed to adjust for demographic factors and preoperative radiographical parameters. Spinopelvic parameters were assessed preoperatively, postoperatively, and at a 2-year follow-up. Mechanical complications were compared between the groups. Results: The FI-PVM(+) group showed greater sagittal vertical axis (86.4 ± 57.5 vs. 51.8 ± 59.2, p < 0.001) preoperatively and required more extensive surgical correction with a significantly greater number of fused vertebral levels (7.3 ± 3.7 vs. 6.7 ± 3.7, p < 0.039). After propensity score matching, both groups showed significant improvement in spinopelvic alignment postoperatively, maintained throughout the 2-year follow-up. However, the FI-PVM(+) group demonstrated a trend toward a higher incidence of distal junctional kyphosis (6.3% vs. 0.9%, p = 0.070) and exhibited significantly greater decrease in pelvic tilt postoperatively (4.3° ± 7.6° vs. 1.3° ± 8.2°, p = 0.006). Conclusion Fat infiltration in PVM is associated with increased surgical complexity and a higher risk of mechanical complications. Preoperative assessment of muscle quality, along with targeted rehabilitation and closer postoperative monitoring, may be crucial for improving long-term outcomes in ASD surgery.

Objective: This multicenter study aimed to evaluate the impact of paravertebral muscles (PVMs) degeneration, particularly fat infiltration, on preoperative sagittal imbalance, and postoperative complications and sagittal alignment change in patients with adult spinal deformity (ASD). Methods: A retrospective analysis was conducted on 454 patients who underwent ASD surgery across 5 institutions. Patients were classified into 2 groups based on paraspinal muscle fat infiltration on MRI: those with significant infiltration (FI-PVM(+)) and those with minimal or no infiltration (FI-PVM(-)). Propensity score matching was performed to adjust for demographic factors and preoperative radiographical parameters. Spinopelvic parameters were assessed preoperatively, postoperatively, and at a 2-year follow-up. Mechanical complications were compared between the groups. Results: The FI-PVM(+) group showed greater sagittal vertical axis (86.4 ± 57.5 vs. 51.8 ± 59.2, p < 0.001) preoperatively and required more extensive surgical correction with a significantly greater number of fused vertebral levels (7.3 ± 3.7 vs. 6.7 ± 3.7, p < 0.039). After propensity score matching, both groups showed significant improvement in spinopelvic alignment postoperatively, maintained throughout the 2-year follow-up. However, the FI-PVM(+) group demonstrated a trend toward a higher incidence of distal junctional kyphosis (6.3% vs. 0.9%, p = 0.070) and exhibited significantly greater decrease in pelvic tilt postoperatively (4.3° ± 7.6° vs. 1.3° ± 8.2°, p = 0.006). Conclusion Fat infiltration in PVM is associated with increased surgical complexity and a higher risk of mechanical complications. Preoperative assessment of muscle quality, along with targeted rehabilitation and closer postoperative monitoring, may be crucial for improving long-term outcomes in ASD surgery.

Objective: This multicenter study aimed to evaluate the impact of paravertebral muscles (PVMs) degeneration, particularly fat infiltration, on preoperative sagittal imbalance, and postoperative complications and sagittal alignment change in patients with adult spinal deformity (ASD). Methods: A retrospective analysis was conducted on 454 patients who underwent ASD surgery across 5 institutions. Patients were classified into 2 groups based on paraspinal muscle fat infiltration on MRI: those with significant infiltration (FI-PVM(+)) and those with minimal or no infiltration (FI-PVM(-)). Propensity score matching was performed to adjust for demographic factors and preoperative radiographical parameters. Spinopelvic parameters were assessed preoperatively, postoperatively, and at a 2-year follow-up. Mechanical complications were compared between the groups. Results: The FI-PVM(+) group showed greater sagittal vertical axis (86.4 ± 57.5 vs. 51.8 ± 59.2, p < 0.001) preoperatively and required more extensive surgical correction with a significantly greater number of fused vertebral levels (7.3 ± 3.7 vs. 6.7 ± 3.7, p < 0.039). After propensity score matching, both groups showed significant improvement in spinopelvic alignment postoperatively, maintained throughout the 2-year follow-up. However, the FI-PVM(+) group demonstrated a trend toward a higher incidence of distal junctional kyphosis (6.3% vs. 0.9%, p = 0.070) and exhibited significantly greater decrease in pelvic tilt postoperatively (4.3° ± 7.6° vs. 1.3° ± 8.2°, p = 0.006). Conclusion Fat infiltration in PVM is associated with increased surgical complexity and a higher risk of mechanical complications. Preoperative assessment of muscle quality, along with targeted rehabilitation and closer postoperative monitoring, may be crucial for improving long-term outcomes in ASD surgery.

Objective: This multicenter study aimed to evaluate the impact of paravertebral muscles (PVMs) degeneration, particularly fat infiltration, on preoperative sagittal imbalance, and postoperative complications and sagittal alignment change in patients with adult spinal deformity (ASD). Methods: A retrospective analysis was conducted on 454 patients who underwent ASD surgery across 5 institutions. Patients were classified into 2 groups based on paraspinal muscle fat infiltration on MRI: those with significant infiltration (FI-PVM(+)) and those with minimal or no infiltration (FI-PVM(-)). Propensity score matching was performed to adjust for demographic factors and preoperative radiographical parameters. Spinopelvic parameters were assessed preoperatively, postoperatively, and at a 2-year follow-up. Mechanical complications were compared between the groups. Results: The FI-PVM(+) group showed greater sagittal vertical axis (86.4 ± 57.5 vs. 51.8 ± 59.2, p < 0.001) preoperatively and required more extensive surgical correction with a significantly greater number of fused vertebral levels (7.3 ± 3.7 vs. 6.7 ± 3.7, p < 0.039). After propensity score matching, both groups showed significant improvement in spinopelvic alignment postoperatively, maintained throughout the 2-year follow-up. However, the FI-PVM(+) group demonstrated a trend toward a higher incidence of distal junctional kyphosis (6.3% vs. 0.9%, p = 0.070) and exhibited significantly greater decrease in pelvic tilt postoperatively (4.3° ± 7.6° vs. 1.3° ± 8.2°, p = 0.006). Conclusion Fat infiltration in PVM is associated with increased surgical complexity and a higher risk of mechanical complications. Preoperative assessment of muscle quality, along with targeted rehabilitation and closer postoperative monitoring, may be crucial for improving long-term outcomes in ASD surgery.

Objective: This multicenter study aimed to evaluate the impact of paravertebral muscles (PVMs) degeneration, particularly fat infiltration, on preoperative sagittal imbalance, and postoperative complications and sagittal alignment change in patients with adult spinal deformity (ASD). Methods: A retrospective analysis was conducted on 454 patients who underwent ASD surgery across 5 institutions. Patients were classified into 2 groups based on paraspinal muscle fat infiltration on MRI: those with significant infiltration (FI-PVM(+)) and those with minimal or no infiltration (FI-PVM(-)). Propensity score matching was performed to adjust for demographic factors and preoperative radiographical parameters. Spinopelvic parameters were assessed preoperatively, postoperatively, and at a 2-year follow-up. Mechanical complications were compared between the groups. Results: The FI-PVM(+) group showed greater sagittal vertical axis (86.4 ± 57.5 vs. 51.8 ± 59.2, p < 0.001) preoperatively and required more extensive surgical correction with a significantly greater number of fused vertebral levels (7.3 ± 3.7 vs. 6.7 ± 3.7, p < 0.039). After propensity score matching, both groups showed significant improvement in spinopelvic alignment postoperatively, maintained throughout the 2-year follow-up. However, the FI-PVM(+) group demonstrated a trend toward a higher incidence of distal junctional kyphosis (6.3% vs. 0.9%, p = 0.070) and exhibited significantly greater decrease in pelvic tilt postoperatively (4.3° ± 7.6° vs. 1.3° ± 8.2°, p = 0.006). Conclusion Fat infiltration in PVM is associated with increased surgical complexity and a higher risk of mechanical complications. Preoperative assessment of muscle quality, along with targeted rehabilitation and closer postoperative monitoring, may be crucial for improving long-term outcomes in ASD surgery.

Methods: A total of 79 patients with cervical myelopathy who underwent cervical laminoplasty at our facility between June 2010 and March 2013 were included in this study. Intraoperative control and final waveform were evaluated based on the trapezius muscle MEPs by measuring the latency and amplitude. A neck pain group comprised patients with higher neck pain Visual Analog Scale scores from preoperative value to 1 year postoperatively. The cross-sectional areas of the trapezius muscles and the MEP latencies and amplitudes were compared between patients with and without neck pain. Results: The latency and amplitude of the control waveforms were not significantly different between groups. The neck pain group had a significantly shorter final waveform latency (neck pain: 23.6±2.5, no neck pain: 25.8±4.5; p =0.019) and significantly larger amplitude (neck pain: 2,125±1,077, no neck pain: 1,630±966; p =0.041) than the no neck pain group. Conclusions Postoperative neck pain was associated with the final waveform latency and amplitude of the trapezius muscle MEPs during cervical laminoplasty. Intraoperative electrophysiological trapezius muscle abnormalities could cause postoperative neck pain.

Methods: The study included 100 patients with cervical myelopathy who underwent surgery at the National Center for Geriatrics and Gerontology in Obu, Japan from June 2010 to March 2013. Before the surgery, neck pain was evaluated using a Visual Analog Scale (a score ≥50 indicated neck pain and a score <50 indicated no neck pain). The preoperative cross-sectional areas of the trapezius muscles were measured with cervical magnetic resonance imaging sagittal T2-weighted images. Cranial stimulation under general anesthesia was used to derive the MEPs, enabling the measurement of latency and amplitude, using preoperative MEPs of the trapezius muscles. Results: The MEP of the trapezius muscle in patients with neck pain had significantly shorter latencies than those in patients who did not have neck pain. However, there was no significant difference in the amplitude between patients with and without neck pain. However, this tended to be greater in patients with neck pain as compared to that in those without neck pain. The cross-sectional area of the trapezius muscle in patients with neck pain was significantly smaller than that in those who did not have neck pain. Conclusions MEPs revealed electrophysiological abnormalities of the trapezius muscles in patients with neck pain, supporting a relationship of neck pain with the trapezius muscles.

Methods: This retrospective study included 35 patients (mean age, 72.8±8.0 years; male, 10; female, 25) who underwent lumbosacral fixation using SAI screws with at least 2 years of follow-up. SAI screw loosening and L5–S bony fusion were assessed using computed tomography. The period for which the screws appeared loose and the risk factors for SAI screw loosening were investigated 2 years after surgery. Results: A total of 70 SAI screws and 70 S1 pedicle screws were inserted. Loosening was observed 0.5, 1, and 2 years after surgery in 17 (24.3%), 35 (50.0%), and 35 (50.0%) SAI screws, respectively. Bony fusion rate at L5–S was significantly lower in patients with SAI screw loosening than in those without screw loosening (65.0% vs. 93.3%, p =0.048). The score for SAI screw contact with the iliac cortical bone and the bony fusion rate at L5–S were significantly lower in the loosening group than in the non-loosening group (1.8±0.5 vs. 2.2±0.3, p <0.001, respectively). Postoperative pelvic incidence–lumbar lordosis was significantly higher in the loosening group than in the non-loosening group (7.9°±15.4° vs. 0.5°±8.7°, p =0.02, respectively). Conclusions SAI screw loosening is closely correlated with pseudoarthrosis at L5–S. Appropriate screw insertion and optimal lumbar lordosis restoration are important to prevent postoperative complications related to SAI screws.

Methods: The subjects were 23 children with LLD ≥20 mm (range, 27–65 mm) treated at Nagoya University Hospital between 2007 and 2017. Whole spine posteroanterior standing radiographs and whole lower limb radiographs in a supine position were recorded. Data were collected for demographics, LLD, Cobb angle, pelvic obliquity, and Nash/Moe index. Scoliosis was defined as a Cobb angle ≥10°. Leg length was measured from the top of the femoral head to the middle of the tibial plafond, and LLD was defined as the difference between the left and right leg lengths. Results: The patients (nine males and 14 females) had a mean age of 14.0 years (range, 5–18 years). The average LLD was 44.3±17.2 mm, with LLDs of 20 to 39 mm, 40 to 59 mm, and ≥60 mm in 13, five, and five subjects, respectively. The average Cobb angle was 13.0°±7.0°, and 15 subjects (65%) had scoliosis. Convexity of the scoliosis was to the short leg side in all cases. The Cobb angle was significantly related to the severity of the LLD (R=0.736, p<0.01), pelvic obliquity (R=0.966, p<0.01), and Nash/Moe index (p<0.05). Conclusions LLD is a common pediatric condition that can cause scoliosis of the spine. Severe scoliosis may develop if the LLD is ≥30 mm. Long-term studies are needed to examine the effect of LLD resolution on the elimination of scoliosis.