Long-term results from in situ fusion for congenital vertebral deformity.

Study Design: Retrospective review of long-term outcome of fusion in situ for congenital vertebral anomaly with particular emphasis on cosmesis and the incidence of reoperation.

Objective: Examination of the success rate of this procedure and of risk factors for failure.

Background: Fusion in situ is the accepted prophylactic treatment to prevent deformity in congenital vertebral anomalies that have a high risk of progression or have been shown to be deteriorating.

Methods: Records of patients who were at least 15 years of age at last examination were reviewed retrospectively. Consideration was given to cosmetic outcome and to the incidence of reoperation.

Results: There were 43 patients in this category, 19 boys and 24 girls, who were at least 15 years of age when last seen. Reoperation had been performed in 11 cases (25.6%). The main finding was that, although the Cobb angle of the fused segment of spine remained constant after fusion, a curve sometimes developed in the whole spine, sometimes (but by no means always) centered on that fused segment. Cosmetic deformity continued to progress in a number of cases.

Conclusions: Localized fusion, whether posterior alone or anterior and posterior combined, was effective in preventing progression of the Cobb angle of the congenitally malformed area but did not control the overall deformity that developed or progressed with growth. Current concepts of the pathomechanism of deformity do not adequately explain the observations, and a more biologic approach is suggested.