CONTRIBUTION OF THE TRACTION VIEW TO PREDICT CORRECTION OF STIFF IDIOPATHIC THORACIC SCOLIOSIS AND TO ASSESS THE EFFECT OF ASSOCIATED ANTERIOR RELEASE

Abstract

Purpose: Indications for anterior release associated with posterior release for stiff idiopathic scoliosis in adults has varied from institution to institution. The traction view is taken as a useful tool to determine whether anterior release is necessary. The purpose of this study was to validate this hypothesis in a homogeneous group of patients with specifically defined idiopathic scoliosis and to determine predictive value of the traction view. Based on this prediction, we then compared postoperative frontal correction in patients with and without anterior release, performed thoracoscopically.

Material and methods: All patients had idiopathic thoracic scoliosis with a Cobb angle greater than 60° and less than 35% reduction on the standard traction view. Cotrel-Dubousset instrumentation was used for release/posterior fusion procedures. A posterior approach was used alone in group 1 patients (n = 46). Group 2 patients (n = 10) underwent thoracoscopic first intention anterior release/fusion.

Results: The postoperative Cobb angle was strongly correlated with the preoperative angle on the traction view (r = 0.86, p < 0.001). The traction view predicted the postoperative Cobb angle actually achieved rather than the degree of correction of the Cobb angle. The severity of the curvature, 81.5° and 83.3° in groups 1 and 2 respectively, and reducibility on the traction view, 61.6° and 62.1° in groups 1 and 2 respectively, were not different. Likewise the postoperative angles were not significantly different between the two groups (47.4° and 45.4° respectively).

Discussion: The traction views were found to predict reduction of the thoracic curvature even for stiff scoliosis but with a wide error. The two groups were comparable since there was no difference in the mean degree of reducibility under traction. Consequently, anterior release did not appear to improve the postoperative correction in the frontal plane.

Conclusion: The traction view does not appear to be sufficiently discriminating to determine the usefulness of anterior release associated with posterior release for the treatment of stiff idiopathic thoracic scoliosis.