A Comparative Analysis of Revision Surgery Before or After 2 Years After Graduation From Growth-friendly Surgery for Early Onset Scoliosis

Abstract

Introduction: After discontinuation of growth-friendly (GF) surgery for early onset scoliosis, patients are termed graduates: they undergo a spinal fusion, are observed after final lengthening with GF implant maintenance, or are observed after GF implant removal. The purpose of this study was to compare the rates of and reasons for revision surgery in two cohorts of GF graduates: before or after 2 years of follow-up from graduation. Methods: A pediatric spine registry was queried for patients who underwent GF spine surgery with a minimum of 2 years of follow-ups after graduation by clinical and/or radiographic evidence. Scoliosis etiology, graduation strategy, number of, and reasons for revision surgery were queried. Results: There were 834 patients with a minimum of 2-year follow-up after graduation who were analyzed. There were 241 (29%) congenital, 271 (33%) neuromuscular, 168 (20%) syndromic, and 154 (18%) idiopathic. 803 (96%) had traditional growing rod/vertical expandable titanium rib as their GF construct and 31 (4%) had magnetically controlled growing rod. Five hundred ninety-six patients (71%) underwent spinal fusion at graduation, 208 (25%) had GF implants retained, and 30 (4%) had GF implants removed. In the entire cohort, there were 108/834 (13%) patients who underwent revision surgery. Of the revisions, 71/108 (66%) occurred as acute revisions (ARs) between 0 and 2 years from graduation (mean 0.6 y), and the most common AR indication was infection (26/71, 37%). The remaining 37/108 (34%) patients underwent delayed revision (DR) surgery >2 years (mean 3.8 y) from graduation, and the most common DR indication was implant issues (17/37, 46%). Graduation strategy affected revision rates. Of the 596 patients with spinal fusion as a graduation strategy, 98/596 (16%) underwent revision, compared with only 8/208 (4%) patients who had their GF implants retained, and 2/30 (7%) that had their GF implants removed (P ≤ 0.001). A significantly higher percentage of the ARs had a spinal fusion as the graduation strategy (68/71, 96%) compared with 30/37 DRs, (81%, P = 0.015). In addition, the 71 patients who underwent AR undergo more revision surgeries (mean: 2, range: 1 to 7) than 37 patients who underwent DR (mean: 1, range: 1 to 2) (P = 0.001). Conclusion: In this largest reported series of GF graduates to date, the overall risk of revision was 13%. Patients who undergo a revision at any time, as well as ARs in particular, are more likely to have a spinal fusion as their graduation strategy. Patients who underwent AR, on average, undergo more revision surgeries than patients who underwent DR. Level of Evidence: Level III, comparative.