7:52 Surgical correction of sagittal deformity in Scheuermann kyphosis

Abstract

Purpose of study: Surgically treated Scheuermann kyphosis cases have been reviewed to evaluate the factors affecting the degree of correction, loss of correction and proximal and distal junctional kyphosis.Methods used: Thirty-nine cases (24 male, 15 female) of Scheuermann kyphosis, treated surgically to relieve persistent pain or progressive deformity, during 1992 to 1999, were reviewed. Median age at operation was 18 years (14 to 53 years). Mean preoperative kyphosis (Cobb angle) was 81 (65-115). The apex of the curve was at T8 or higher in 20 cases and at T9 or lower in 19 cases. Flexible curves, which bend down to below 45 on hyperextension bending X-ray (n=12) had one-stage posterior surgery only, using segmental instrumentation. Rigid curves (greater than 45 on bending films) had either thoracoscopic anterior release (n=17) or open anterior release (n=10), followed by antero-posterior (AP) instrumentation.of findings: Mean follow-up was 45 months (26 to 140 months). The mean direct postoperative kyphosis was 47.2 degrees (38 to 75 degrees), and mean loss of correction at final follow-up was 9.3 degrees (0 to 17 degrees). Kyphosis correction achieved at final follow-up ranged from 39% after posterior-only surgery, to 42% after thoracoscopic AP surgery and 48% after open AP surgery. Mean loss of correction was 12 degrees after posterior-only surgery, 9.5 degrees after thoracoscopic AP surgery and 6 degrees after open AP surgery. Four cases of open AP surgery had additional anterior structural support with cages, before posterior instrumentation. A mean 55% kyphosis correction was achieved in this group, and there was no loss of correction. Younger cases, under 18 years (n=21) had significantly better kyphosis correction than the older age group (p<.05). Four cases (10%) developed distal junctional kyphosis resulting from fusion short of the first lordotic segment. All of them had the apex below T9. Six cases (15%) developed proximal junctional kyphosis; all of them had the apex above T6. Complications included infection (four), pneumothorax (one), heamothorax (one), instrumentation failure (four cases); three cases had persistent back pain.Relationship between findings and existing knowledge: No correlation between the four different types of curves described in the literature (upper, middle, lower and whole thoracic) and the outcome was found in this study.Overall significance of findings: Combined anterior release and posterior surgery achieves and maintains better correction of Scheuermann kyphosis. Anterior structural support prevents loss of correction. Proximal junctional kyphosis is more common in higher curves, and distal junctional kyphosis is more common in lower curves. Correction is better achieved in younger patients but is not influenced by the location of the curve.Disclosures: Device or drug: pedicle screws and rods. Status: approved.Conflict of interest: No conflicts.