The Efficacy of Convex Hemiepiphysiodesis in Patients with Iatrogenic Posterior Element Deficiency due to Diastematomyelia Excision

Purpose: Anterior and posterior convex hemiepiphysiodesis is a well accepted treatment method for severe and progressive congenital scoliosis in young children. Many patients with congenital spinal deformities have intraspinal pathologies that require neurosurgical intervention with laminectomy. The efficacy of this method has not been studied in these patient populations. The purpose of this study is to investigate the safety and efficacy of anterior and posterior hemiepiphysiodesis in patients with iatrogenic posterior element deficiency.

Materials and Methods: Between 1990-2001, 82 patients with congenital spinal deformity were treated with convex epiphysiodesis. Sixteen patients (2 male, 14 female) who underwent diastematomyelia excision and were followed up for at least 2 years were included. Diastematomyelia excision was performed before the orthopaedic procedure in 8 patients and at the same stage in 8 patients. Mean age at the time of the fusion was 18 months (6-48) and, average follow-up was 41 months (24-120).

Results: The meanCobb angle was 58o (31-115) preoperatively and, 54 o (30-90) at final follow-up. Any increase more than 6 degrees was accepted as progression. Seven patients (44%) had a true epiphysiodesis effect [64o(40-115) preoperatively, and 49o (30-90) at follow-up]; 7(44%) patients had a fusion effect [50o(31-68) preoperatively and 53o(36-73) at follow-up]. Two patients (12%) had a postoperative progression of deformity [63o(54-72) preop. and 75o(65-84) follow-up].

Conclusion: Convex epiphysiodesis is an effective method in patients with midline laminectomy defect as is in the patients with intact posterior elements. Since the facet joints and transverse processes are usually unaffected, the presence of midline defect does not diminish the efficacy of the technique.