Postoperative coronal imbalance is a significant problem after selective thoracic fusion for primary thoracic and compensatory lumbar curves in adolescent idiopathic scoliosis (AIS). However, longitudinal studies on postoperative behavior of coronal balance are lacking. This multicenter retrospective study was conducted to analyze factors related to onset and remodeling of postoperative coronal imbalance after posterior thoracic fusion for Lenke 1C and 2C AIS. Twenty-one Lenke 1C or 2C AIS patients, who underwent posterior thoracic fusion ending at L3 or above, were included with a minimum 2-year follow-up. The mean patients’ age was 15.1 years at the time of surgery. Radiographic measurements were performed on Cobb angles of the main thoracic (MT) and thoracolumbar/lumbar (TLL) curves and coronal balance. Factors related to the onset of immediately postoperative coronal decompensation (IPCD) and postoperative coronal balance remodeling (PCBR), defined as an improvement of coronal balance during postoperative follow-up, were investigated using comparative and correlation analyses. Mean Cobb angles for the MT and TLL curves were 57.3° and 42.3° preoperatively and were corrected to 22.8° and 22.5° at final follow-up, respectively. Mean preoperative coronal balance of −3.8 mm got worse to −21.2 mm postoperatively, and regained to −12.0 mm at final follow-up. Coronal decompensation was observed in two patients preoperatively, in ten patients immediately postoperatively, and in three patients at final follow-up. The preoperative coronal balance and lowest instrumented vertebra (LIV) selection relative to stable vertebra (SV) were significantly different between patients with IPCD and those without. PCBR had significantly negative correlation with immediately postoperative coronal balance. IPCD after posterior thoracic fusion for Lenke 1C and 2C AIS was frequent and associated with preoperative coronal balance and LIV selection. However, most patients with IPCD regained coronal balance through PCBR, which was significantly associated with immediately postoperative coronal balance. A fixation more distal to SV shifted the coronal balance further to the left postoperatively.

Background and Objectives: The incidence of pyogenic spondylodiscitis has been increasing due to the aging of the population. Although surgical treatment is performed for refractory pyogenic spondylodiscitis, surgical invasiveness should be considered. Recent minimally invasive spine stabilization (MISt) using percutaneous pedicle screw (PPS) can be a less invasive approach. The purpose of this study was to evaluate surgical results and clinical outcomes after MISt with PPS for pyogenic spondylodiscitis. Materials and Methods: Clinical data of patients who underwent MISt with PPS for pyogenic spondylitis were analyzed. Results: Twenty-three patients (18 male, 5 female, mean age 67.0 years) were retrospectively enrolled. The mean follow-up period was 15.9 months after surgery. The causative organism was identified in 16 cases (69.6%). A mean number of fixed vertebrae was 4.1, and the estimated blood loss was 145.0 mL. MISt with PPS was successfully performed in 19 of 23 patients (82.6%). Four cases (17.4%) required additional anterior debridement and autologous iliac bone graft placement. CRP levels had become negative at an average of 28.4 days after surgery. There was no major perioperative complication and no screw or rod breakages during follow-up. Conclusions: MISt with PPS would be a less invasive approach for pyogenic spondylodiscitis in elderly or immunocompromised patients.