Safety and Efficacy of Instrumented Convex Growth Arrest in Treatment of Congenital Scoliosis

Background: Anterior and posterior convex hemiepiphysiodesis is a widely used surgical alternative in the treatment of congenital scoliosis. This procedure has the disadvantage of the need for both anterior and posterior approaches. Furthermore, outcomes may be unpredictable. Posterior convex growth arrest (CGA) with pedicle screws at each segment on the convex side may obviate the need for anterior surgery and provides more predictable outcomes. This study retrospectively evaluates the safety and efficacy of instrumented posterior CGA in congenital scoliosis. Methods: Patients who had posterior CGA with convex pedicle screw instrumentation for congenital scoliosis were evaluated retrospectively. Thirteen patients (6 male, 7 female) were included in the study. Preoperative, early postoperative, and last follow-up standing posteroanterior and lateral x-rays were evaluated. Cobb angles were recorded for the instrumented segment (main curve). Global thoracic kyphosis was measured between T2 and T12 on sagittal plane. These values were compared preoperatively, postoperatively, and at last follow-up. The T1-S1 vertical height and the height between the concave side pedicles of the upper and lower end vertebra of the main curve was also determined and recorded as the concave height. Results: The average follow-up was 56.1 +/- 10 months (range, 36 to 74 mo) and the average age of the patients at the time of operation was 64.5 +/- 30.1 months (range, 15 to 108 mo). All patients were Risser zero at the time of surgery. The average curve magnitude was 49 +/- 10.9 degrees (range, 34 to 68 degrees) preoperatively, 38.3 +/- 9.7 degrees (range, 28 to 58 degrees) early postoperatively, and 33.5 +/- 12.4 degrees (16 to 52 degrees) at last follow-up. There was a significant difference between the preoperative and early postoperative main curve Cobb angle measurements (P=0.001). The average concave height was 94.2 +/- 20.2 mm in the early postoperative period and 104.7 +/- 21.7 mm at last follow-up (P=0.003). The average T1-S1 height was 292.1 +/- 67.1 mm in the early postoperative period and 363.9 +/- 94.5 mm at last follow-up (P=0.005). There was at least >= 5 degrees improvement in 9 of the 12 patients in the follow-up period after the index procedure. In 3 patients, the curve did not change and the correction was maintained. Curve progression was observed in 1 patient due to a technical error. There were no wound infections or instrumentation failures during follow-up. Conclusions: Instrumented CGA can safely be used in long sweeping curves of immature spines. Using this technique; thoracotomy, anterior procedure, and 2-stage surgery can be avoided. Moreover, it guarantees some degree of correction in all patients because of the instrumentation effect, eliminating the unpredictable nature of classic CGA. Level of Evidence: Therapeutic level IV study.