Preservation of Spine Motion in the Surgical Treatment of Adolescent Idiopathic Scoliosis Using an Innovative Apical Fusion Technique: A 2-Year Follow-Up Pilot Study

Abstract

Background: This trial reports the 2-year and immediate postremoval clinical outcomes of a novel posterior apical short-segment (PASS) correction technique allowing for correction and stabilization of adolescent idiopathic scoliosis (AIS) with limited fusion.Methods: Twenty-one consecutive female AIS patients were treated at 4 institutions with this novel technique. Arthrodesis was limited to the short apical curve after correction with translational and derotational forces applied to upper and lower instrumented levels. Instrumentation spanned fused and unfused segments with motion and flexibility of unfused segments maintained. The long concave rods were removed at maturity. Radiographic data collected included preoperative and postoperative data for up to 2 years as well as after long rod removal.Results: All 21 patients are beyond 2 years postsurgery. Average age at surgery was 14.2 years (11-17 years). A mean of 10.5 6 1 levels per patient were stabilized and 5.0 6 0.5 levels (48%) were fused. Cobb angle improved from 56.18 6 8.08 to 20.88 6 7.88 (62.2% improvement) at 1 year and 20.98 6 8.48, (62.0% improvement) at 2 years postsurgery. In levels instrumented but not fused, motion was 268 6 68 preoperatively compared to 108 6 48 at 1 year postsurgery, demonstrating 38% maintenance of mobility in nonfused segments. There was no report of implant-related complications.Conclusions: PASS correction technique corrected the deformity profile in AIS patients with a lower implant density while sparing 52% of the instrumented levels from fusion through the 2-year follow-up.