Scoliosis flexibility correlates with post-operative outcomes following growth friendly surgery.

Abstract

The purpose of this study was to determine the relationship between pre-operative scoliosis flexibility and post-operative outcomes, including curve correction and complications, for patients who have been treated with growth friendly surgery (GFS) for early onset scoliosis (EOS). The study was conducted as a retrospective review of prospectively collected data from an international, multicenter, EOS database. EOS patients with pre-operative flexibility radiographs (traction or bending) were identified. Pre-operative flexibility and immediate post-operative correction were calculated for each patient. Post-operative complications were recorded at final follow-up. Pearson correlations were determined for flexibility vs correction for all patients and were compared between etiologies and between device types (MCGR, TGR, VEPTR). 107 patients (14 congenital, 43 neuromuscular, 31 syndromic, 19 idiopathic) with mean age 7.1years at index surgery were identified. Mean pre-operative scoliosis was 77°. Mean flexibility of 36% was not significantly different between etiologies. Mean immediate post-operative scoliosis was 46° (p < 0.001 vs. pre-operative) with mean correction of 38%. Correction rate was not significantly different between etiologies; however, correction rate was different between device types (MCGR 45%, TGR 40%, VEPTR 14%; p = < 0.001). Pearson correlation for flexibility vs correction was fair (r = 0.37, p < 0.001). This correlation was observed for idiopathic (r = 0.53, p = 0.020) and neuromuscular (r = 0.46, p = 0.0020) scoliosis, but not for congenital or syndromic scoliosis. At a mean of 6.1year follow-up (minimum 2years to 15.5years), 60 of 81patients (74%) experienced at least one complication. Odds ratio for developing a complication was 3.00 (1.03-8.76) for patients with pre-operative flexibility < 45% (p < 0.05). As lower pre-operative flexibility was associated with less scoliosis correction and with a higher risk of post-operative complications, curve flexibility should be considered when deciding upon the timing of growth friendly surgery. Level III-retrospective comparative study.