Comparison of Segmental Pedicle Screw Instrumentation Versus Anterior Instrumentation in Type I Adolescent Idiopathic Scoliosis

Introduction: The purpose of our study is to compare the results of segmental pedicle screw instrumentation versus anterior instrumentation in King type I adolescent idiopathic scoliosis.

Methods: A retrospective analysis was conducted on thirty-six consecutive female patients with King type I adolescent idiopathic scoliosis who had surgery from December 1997. All had a minimum of 2- year follow-up. Eleven patients had posterior surgery performed on them.

Results: Mean age at surgery was similar between both groups. Length of surgery was significantly shorter in Group 2 (189 minutes versus 272 minutes). Length of stay was shorter in Group 2 (6.2 days versus 8 days). Estimated blood loss, duration of analgesia, and ICU stay did not differ significantly between the two groups. No complications were encountered in both groups at latest follow-up. The magnitudes of the thoracolumbar curves did not differ significantly between the two groups. Flexibility of these curves was similar between the two groups. The number of levels in the major curve was also similar between the groups. Fusion levels were shorter in Group 1 (mean 4.1 versus 5.0). The percentage correction of frontal alignment in Group 1 was 74% at 1 week post-surgery, 70% at 6 months post-surgery, 68% at 1 year postsurgery and latest follow-up. The percentage correction of scoliosis in Group 2 was 71% at 1 week postsurgery, 67% at 6 months post-surgery, 68% at 1 year post-surgery, and 67% at latest follow-up. The correction was similar between the two groups at all stages of follow-ups.

Discussion: Posterior segmental pedicle screw instrumentation is a viable alternative to standard anterior instrumentation in King 1 idiopathic scoliosis. Shorter OR time and hospital stay are the potential benefits of posterior surgery. Surgical correction of both the frontal and sagittal plane deformity are comparable to anterior instrumentation.