Ambulatory Patients With Early Onset Scoliosis Have Similar Complication Profiles Following MCGR Treatment Across All Classification Etiologies.

Abstract

Studies evaluating outcomes following the surgical treatment of early onset scoliosis (EOS) often stratify their results within the classification of EOS (C-EOS) categories based on the assumption that the complication risk differs across etiology. Complication risk across C-EOS categories among ambulatory patients has not been thoroughly evaluated. The purpose was to test for differences in the incidence of unplanned return to the operating room (UPROR) following magnetically controlled growing rod (MCGR) implantation among ambulatory patients with idiopathic (IS) EOS relative to ambulatory patients with EOS secondary to congenital, syndromic, or neuromuscular conditions (Non-IS). A multicenter pediatric spine database was queried to identify all ambulatory patients with EOS who underwent an index MCGR surgery from 2011 to 2019 and a 2-year follow-up (n=518). Patients in the IS group were matched to patients in the non-IS group using a nearest neighbor propensity score methodology. Patients were matched at a 1:1 ratio based on age, primary Cobb angle, midpoint of primary curve, and degree of kyphosis. To test our equivalence hypothesis, we evaluated the lower and upper 95% CI relative to our a priori clinically relevant threshold, +/- 20%. A total of 133 patients with IS were matched to 133 patients with non-IS diagnoses. The risk of UPROR was 12.3% in the IS group compared with 13.9% in the non-IS group. The risk difference and corresponding 95% CI (risk difference: +1.5%, 95% CI: -6.7% to +9.7%) were less than our clinically relevant risk thresholds (95% CI limits within ±20%). Previous studies have demonstrated worse UPROR rates associated with neuromuscular and syndromic EOS etiology, our data demonstrate that among ambulatory patients, UPROR rates do not differ by etiology. This suggests that ambulatory status may be a stronger driver of UPROR than etiology as ambulatory status is likely a surrogate for medical complexity/disease severity. Level III.