Surgical Outcomes of Anterior Versus Posterior Fusion in Lenke Type 1 Adolescent Idiopathic Scoliosis

Study Design: Retrospective study.

Objective: To describe surgical results in two and three dimensions and patient-reported outcomes of scoliosis treatment for Lenke type 1 idiopathic curves with an open anterior or posterior approach.

Summary Of Background Data: Different surgical techniques have been described to prevent curve progression and to restore spinal alignment in idiopathic scoliosis. The spine can be accessed via an anterior or a posterior approach. However, the surgical outcomes, especially in three dimensions, for different surgical approaches remain unclear.

Methods: Cohorts of Lenke curve type 1 idiopathic scoliosis patients, after anterior or posterior spinal fusion were recruited, to measure curve characteristics on conventional radiographs, before and after surgery and after 2 years follow-up, whereas the vertebral axial rotation, true mid-sagittal anterior-posterior height ratio of individual structures, and spinal height differences were measured on 3D reconstructions of the pre- and postoperative supine low-dose computed tomography (CT) scans. Additionally, the intraoperative parameters were described and the patients completed the Scoliosis Research Society outcomes and the 3-level version of EuroQol Group questionnaires postoperatively.

Results: Fifty-three patients with Lenke curve type 1 idiopathic scoliosis (26 in the anterior cohort and 27 in the posterior cohort) were analyzed. Fewer vertebrae were instrumented in the anterior cohort compared with the posterior cohort (P < 0.001), with less surgery time and lower intraoperative blood loss (P < 0.001). The Cobb angle correction of the primary thoracic curve directly after surgery was 57 ± 12% in the anterior cohort and 73 ± 12% in the posterior cohort (P < 0.001) and 55 ± 13% and 66 ± 12% (P = 0.001) at 2 years follow-up. Postoperative 3D alignment restoration and questionnaires showed no significant differences between the cohorts.

Conclusion: This study suggests that Lenke type 1 curves can be effectively managed surgically with either an open anterior or posterior approach. Each approach, however, has specific advantages and challenges, as described in this study, which must be considered before treating each patient.

Level Of Evidence: 3.