Abstract / Summary
Abstract Purpose To evaluate whether the discrepancy between planned and postoperative T4T12 thoracic kyphosis (TK) using patient-specific rods (PSR) differed between hypokyphotic and normokyphotic adolescent idiopathic scoliosis (AIS) patients. Methods Consecutive AIS patients undergoing posterior spinal fusion (PSF) with PSR for thoracic structural curves were retrospectively analyzed from prospectively collected data. Patients were classified as hypokyphotic (T4T12 TK < 20°) or normokyphotic (20–40°). Preoperative, planned, and postoperative radiographic parameters were compared. TK plan execution was considered excellent when the absolute postoperative-to-planned difference was < 5°, acceptable between 5° and 15°, and insufficient when > 15°. Results Two hundred and ten patients were included, including 92 hypokyphotic (43.8%) and 118 normokyphotic. Preoperative T4T12 TK was 11°±7 versus 29°±6, respectively (p < 0.001), while planned TK was 31°±5 versus 34°±4 (p < 0.001). Postoperatively, TK increased to 21°±7 in hypokyphotic patients and remained stable (30°±6) in normokyphotic ones. The difference with the TK target was significantly greater in the hypokyphotic group (10°±5 vs 4°±7, p < 0.001). TK plan execution was excellent or acceptable in 85% of the overall cohort, but insufficient in 20% of hypokyphotic patients. Conclusion PSR effectively restored sagittal spinal shape in AIS, but TK predictions were frequently too optimistic in hypokyphotic patients. Planning should therefore better take into account patients’ preoperative specific sagittal alignment, as well as surgeon-specific correction techniques.