Use of Magnetic Spinal Growth Rods (MCGR) with and Without Preoperative Halo-gravity Traction (HGT) for the Treatment of Severe Early-onset Scoliosis (EOS)

Background: Correction of severe scoliosis through distraction-based techniques poses a challenge. Magnetically controlled growing rod (MCGR) hardware complications are common with a 27.8% to 46.7% revision rate in under 2 years. Loss of correction and diminishing returns are the norm. Treatment of severe scoliosis with halo-gravity traction (HGT) before MCGR has not been previously reported. The purpose of this study was to assess initial correction, maintenance of correction, and complication rate in patients with severe scoliosis treated with and without HGT before MCGR. Methods: IRB-Approved retrospective single site cohort study of a prospectively collected database. Forty-Two patients underwent MCGR between 2014 and 2017 at a single site, 12 with prior growing constructs were excluded, 30 patients were included, 12 patients underwent preoperative HGT. Charts were reviewed for demographic, clinical, and radiographic information. Results: The HGT group had larger major curves averaging 90 (69 to 114) degrees versus 77 (56 to 113) degrees in the non-HGT group P=0.018. Percent correction on preoperative flexibility films were 17% versus 40% for those in the HGT versus non-HGT group, P=0.000. An additional 22% correction of the curve magnitude occurred between the flexibility and in-Traction films representing 43% of the total correction achieved, P=0.000, was achieved. EBL, and postoperative major curve and major curve correction were not significant. Thirteen percent of patients experienced complications. Average follow-up was 712 versus 561 days in the HGT versus non-HGT groups. Conclusions: Large, rigid curves can achieve equivalent correction to flexible curves with HGT. Forty-Three percent of the total correction achieved occurred during traction. Thirty percent of the total correction occurred at implantation of the MCGR in the HGT group versus 28% in the non-HGT group. At most recent follow-up HGT patients had statistically maintained their major curve correction better than non-HGT patients. Level of Evidence: Level III-therapeutic study.