Study Design. Retrospective analysis was performed. Objective. To investigate the safety and efficacy of anterior and posterior hemiepiphysiodesis in patients with iatrogenic posterior element deficiency. Summary of Background Data. 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. Methods. Between 1990 and 2001, among 82 patients with congenital spinal deformity, 38 were treated with convex epiphysiodesis. This study included 18 of these patients (2 males and 16 females) who underwent diastematomyelia excision and had at least 2 years of follow-up evaluation. Diastematomyelia excision was performed before the orthopedic procedure in 8 patients and at the same anesthetic setting sequentially in 10 patients. The mean age at the time of the fusion was 20 months (range, 6-60 months), and the average follow-up period was 39 months (range, 24-120 months). Results. The mean Cobb angle was 54° (range, 31-90°) before surgery and 48° (range, 30-84°) at the final follow-up assessment. Any increase of more than 6° was accepted as progression. Eight patients (44%) had a true epiphysiodesis effect: 58° (range, 40-90°) before surgery and 39° (range, 30-70°) at follow-up evaluation. Eight patients (44%) had a fusion effect: 49° (range, 31-68°) before surgery and 50° (range, 37-74°) at follow-up assessment. Two patients (12%) had a postoperative progression of deformity: 63° (range, 54-72°) before surgery and 75° (range, 65-84°) at follow-up evaluation. Conclusions. Convex epiphysiodesis is an effective method for patients with midline laminectomy defect as those with intact posterior elements. Because the facet joints and transverse processes usually are unaffected, the presence of midline defect does not diminish the efficacy of the technique.