Growth guidance constructs with apical fusion and sliding pedicle screws (SHILLA) results in approximately 1/3rd of normal T1-S1 growth.

Abstract

Retrospective, multicenter. To investigate clinical outcomes in particular T1-S1 growth in patients with SHILLA instrumentation independent of inventor's reports. Guided growth with apical fusion and sliding pedicle screws (GGC/SHILLA) is an alternative to distraction-based growing rods for the treatment of EOS. A recent report of patients treated with GGC primarily at the center where the procedure was invented reported surprisingly good spinal growth similar to normal growth. Retrospective review of EOS patients treated with GGC between 2007 and 2013 was performed from a multicenter database prior to final fusion. Inclusion criteria were < 10 years at index surgery and minimum 2-year follow-up. Patients with GGC performed at the inventor's institution or prior spinal instrumentation were excluded. Predicted normal T1-S1 change during the growth period was calculated for each patient based on Dimeglio's growth rates. 20 patients (mean age at surgery: 5.7 years) with the following diagnoses met inclusion criteria: syndromic (N = 9), neuromuscular (N = 5), idiopathic (N = 3) and congenital (N = 3). Preoperative mean Cobb was 77° (range 33°-111°). Mean increase in T1-S1 length from preoperative to postoperative was 51.5 mm, and change from postoperative to final follow-up was 21.8 mm (4.2 mm/year) which was 36% of predicted growth. 15/20 (75%) patients underwent 21 revision surgeries most commonly for implant complications (N = 26) and 8/20 (40%) underwent definitive fusion at a mean of 5.1 ± 1.2 years after guided growth surgery. This study constitutes the largest case series of patients with EOS treated with GGC outside of the inventor's institution. The change in T1-S1 observed through the follow-up period in EOS patients treated with GGC was approximately 1/3rd of predicted normal growth, and less than 1/3rd of growth reported in previous reports. Similar curve correction and complication rates but less T1-S1 growth during the growth period were found compared to prior GGC (SHILLA) series.