Postoperative proximal junctional kyphosis in Lenke 5C adolescent idiopathic scoliosis following posterior surgery: extending fusion versus thoracolumbar/lumbar fusion

Abstract

Background: Proximal junctional kyphosis is a common complication after posterior fusion in adolescent idiopathic scoliosis patients, and was correlated with postoperative change of thoracic kyphosis. However, no previous literature has evaluated the correlation of PJK with thoracervical parameters in the AIS patients. Methods: Data from 61 patients who underwent posterior fusion for Lenke 5C AIS and had 2 years of follow-up were retrospectively reviewed. Patients were fused higher than two levels above the upper-end-vertebra in the extended fusion group (n=32), whereas they were fused below or at UEV+2 in the TL/L fusion group (n=29). Results: During an average follow-up of 32.5 months, 14/61 patients had PJK. The extended fusion group had a greater incidence of PJK than the TL/L fusion group did (11/32 vs. 3/29,P = 0.03) and a significant more decrease of TK than the TL/L group(p<0.01). Patients with PJK had a significantly larger Thoracic inlet angle(TIA) than those without PJK (P <0.01). Multivariate analysis revealed a greater preoperative TIA to be a positive predictor for PJK (p = 0.015). TIA >72° with extended fusion was a risk factor for PJK at final follow-up. The SRS-22 score did not significantly differ between the extended fusion and TL/L fusion groups. Conclusions: TIA could be a predictor of PJK. In Lenke 5C AIS patients, those with TIA >72° were more likely to develop PJK. And extended fusion in patients with Lenke 5C adolescent idiopathic scoliosis may be at an increased risk of proximal junctional kyphosis.