Anterior versus Posterior Spinal Instrumentation for the Treatment of Thoracolumbar Curves in Adolescent Idiopathic Scoliosis

Purpose: Thoracolumbar curves in adolescent idiopathic scoliosis may be treated surgically with anterior or posterior spinal instrumentation, with little evidence in the literature to suggest superiority of either technique. The purpose of this study is to compare anterior vs. posterior instrumentation in a well-defined population of patients with adolescent idiopathic scoliosis with thoracolumbar scoliosis.

Methods: Medical records and radiographs of all patients undergoing spinal instrumentation for the treatment of adolescent idiopathic scoliosis with primary thoracolumbar curves, defined as curve apices between T10 and L2, between 1993 and 2001 were reviewed. The study group consists of 12 patients treated with anterior spinal instrumentation and 16 with posterior instrumentation. Various radiographic and outcome measures were compared between groups.

Results: The anterior group had 75% correction of the primary Cobb angle compared to 56% in the posterior group (P = 0.019). An average of 3.8 vertebral levels in the anterior and 6.7 in the posterior procedures were fused (P <0 .001). Less blood loss was observed in the anterior group (P="" 0.007), with fewer transfusions as well ( P < 0.001). The produced more lumbar lordosis (p="0.047).

Discussion: This study comparing anterior versus posterior instrumentation is unique in that it is limited to thoracolumbar curves. While earlier series of anterior instrumentation revealed high rates of hardware failure and pseudoarthrosis, this series found no instance of either in the anterior group. In addition, concern over anterior compression instrumentation causing kyphosis proved unwarranted. In fact, the anterior instrumented group had improved lumbar lordosis compared to the posterior.

Conclusions: In thoracolumbar idiopathic curves, anterior instrumentation had a significantly improved Cobb angle, less levels fused, and more lumbar lordosis, and less blood transfusions when compared to posterior instrumentation. In addition, patients undergoing anterior instrumentation had a significantly lower rate of revision surgery compared to those with posterior instrumentation.