Osteotomies At The Time of Graduation Surgery: How Much Do We Get from Them?

STUDY DESIGN: Retrospective, Multicenter.

OBJECTIVE: Determine if posterior column osteotomies (PCO) at time of conversion from growth friendly instrumentation (GFI) to definitive fusion in early onset scoliosis (EOS) graduates impacts outcomes.

SUMMARY OF BACKGROUND DATA: Increasing spinal rigidity following treatment of EOS with GFI can limit curve correction at time of conversion to definitive spinal fusion. PCO are often employed at the time of fusion to improve flexibility. This technique's efficacy has not been studied.

METHODS: EOS patients with GFI undergoing conversion to fusion were grouped by those that did or did not have PCO. Patients with inadequate radiographs, <2 years follow-up, or three-column osteotomies at time of fusion were excluded.

RESULTS: 832 patients met inclusion criteria. 175 (21%) patients had PCO. Age at index surgery was younger (6.6 vs. 7.4 y, P =0.0009) and the mean duration of GFI was greater (6.2 vs. 5.5 y, P =0.009) in the PCO group. Prior to fusion, curve magnitude was similar between the groups (PCO=61.9 degrees, no PCO=59.3 degrees, P=0.18). On average 4.4 osteotomies (range: 1 - 12) were performed for the PCO group and EBL (PCO=820 cc vs no PCO=752 cc, P<0.01) and surgical time (PCO=403 min vs no PCO=349 min, P<0.01) were greater. Postoperatively, mean curve correction (PCO=16.6, no PCO=14.4 degrees, P=0.18) was similar. Accounting for preoperative curve magnitude, there was a relationship between number of PCOs and curve correction (P=0.04). There was no relationship between degrees of correction per osteotomy and duration of GFI (P=0.12). Postoperative complications at 2 years were similar (PCO=25% vs no PCO=27%, P=0.63).

CONCLUSION: EOS graduates achieve minimal correction at time of conversion regardless of whether PCOs are performed. PCOs increase EBL and operative time but have a similar complication rate. More PCOs resulted in more correction, though less than that anticipated in a previously uninstrumented spine.

LEVEL OF EVIDENCE: III.