SAGITTAL BALANCE IN SCHEUERMANN’S KYPHOSIS – RESULTS OF SURGICAL TREATMENT IN 35 CASES

Abstract

Introduction: Surgical treatment is indicated in Scheuermann’s disease with severe kyphotic deformity, and/or unremitting pain. Proximal or distal junctional kyphosis and loss of correction have been reported in the literature, due to short fusion level, overcorrection, or posterior only surgery with failure to release anterior tethering. We reviewed surgically treated Scheuermann’s kyphosis cases, to evaluate the factors affecting the sagittal balance.

Methods and results: 35 cases (22 male, 13 female) of Scheuermann’s kyphosis were treated surgically in this centre during 1993–1999. Mean age at operation was 21.5 years (14–53 years). The kyphosis was high thoracic (Gennari Type I) in two cases, mid thoracic (Type II) in 11 cases, low thoracic or thoraco-lumbar (Type III) in eight cases, and whole thoracic (Type IV) in 14 cases. Mean pre-operative kyphosis (Cobb angle) was 81° (range 70° to 110°). Ten cases (mean kyphosis 77°) had one stage posterior operation only with segmental instrumentation. Twenty-five cases had combined anterior and posterior (A-P) surgery. Fifteen cases (mean kyphosis 81°) had one stage thoracoscopic release and posterior instrumentation, and 10 cases (mean kyphosis 89°) had open anterior release, followed by second stage posterior instrumentation. Minimum follow-up was 14 months (mean 45 months, range 14–140 months). The mean post-operative kyphosis was 47.2°. Kyphosis correction achieved ranged from 39% after posterior surgery only, to 42% after thoracoscopic A-P surgery, and 48% after open A-P surgery. Mean loss of correction was 12° after posterior only surgery, 9.5° after thoracoscopic A-P surgery, and 6° after open A-P surgery. Four cases of open A-P surgery had additional anterior cages to stabilise the kyphosis before posterior instrumentation; a mean 55% kyphosis correction was achieved in this group, and there was no loss of correction. Younger cases, under 25 years (n=16) had significantly better kyphosis correction (p< 0.05). Two cases (6%) developed distal junctional kyphosis due to fusion short of the first lordotic segment, requiring extension of fusion. Four cases (12%) developed proximal junctional kyphosis requiring extension of fusion; all of them had primary posterior surgery only. Location of the curve (Gennari Type) had no significant influence on the initial curve, degree of immediate correction, or loss of correction. Complications included infection (4 cases), pneumothorax (1 case), haemothorax (1 case), instrumentation failure (3 cases); 3 cases had persistent back pain.

Conclusion: Combined anterior release and posterior surgery achieves and maintains better correction of Scheuermann’s kyphosis. Loss of correction, and proximal junctional kyphosis are more frequent after posterior surgery only, and short fusion. Use of cages anteriorly prevents loss of correction. Correction is better achieved in younger patients, but is not influenced by the location of the curve.