The Efficacy of Proximal Lumbar Curve Flexibility in Patients with Main Thoracic Adolescent Idiopathic Scoliosis Treated by Selective Thoracic Fusion Surgery

STUDY DESIGN Retrospective radiographic study. PURPOSE To evaluate the efficacy of the proximal lumbar curve flexibility compared with the traditional whole lumbar curve flexibility in patients with main thoracic adolescent idiopathic scoliosis (MT-AIS). OVERVIEW OF LITERATURE Traditionally the flexibility of the whole lumbar curve was measured, and the flexibility of the proximal lumbar curve was not analyzed in any study. METHODS Twenty-eight MT-AIS patients treated by anterior selective thoracic fusion (STF) were evaluated after mean follow-up of 50.1 months (range, 25 to 116 months). The male : female ratio was in 5 : 23. The man age at surgery was 14 years and 8 months (range, 11.4 to 18.4 years). The lumbar curve was divided into the proximal and distal curves by the lumbar apex. RESULTS The mean final correction rates (CR)/(flexibilities) of the MT, lumbar, proximal lumbar, and distal lumbar curves were 65.2%/(50.5%), 61.9%/(92.8%), 65.3%/(90.9%), and 36.4%/(134%), respectively. With the final lumbar CR, the lumbar flexibility (r = 0.267, p > 0.05) and the proximal lumbar flexibility (r = 0.327, p > 0.05) was similarly correlated. The mean lumbar CR was similar to the proximal lumbar CR (61.9% vs. 65.3%, p = 0.305). And the correlation between the flexibility and the CR was significant only in the proximal lumbar curve (r = 0.457, p < 0.05), but not in the lumbar curve (r = 0.267, p > 0.05) or the distal lumbar curve (r = 0.175, p > 0.05). CONCLUSIONS The proximal lumbar curve flexibility may be an alternative method of measuring the lumbar flexibility in MT-AIS patients treated by STF.