Patient-based outcomes analysis of patients with single torsion thoracolumbar-lumbar scoliosis treated with anterior or posterior instrumentation: an average 5- to 9-year follow-up study.

INTRODUCTION: Since the advent of single, stiff rod anterior instrumentation, and now dual rod anterior instrumentation, most thoracolumbar-lumbar scoliosis is treated with an anterior approach. We have previously reported a retrospective comparison of patients with single torsion thoracolumbar-lumbar scoliosis treated with either anterior or posterior instrumented fusion. The purpose of this study is to examine the patient-based outcomes in this cohort of patients at an average of 5 years (anterior instrumentation) and 9 years (posterior instrumentation).
MATERIALS AND METHODS: Inclusion criteria were as follows: 1) single torsion thoracolumbar or lumbar curve of <or=70 degrees; 2) thoracic curve bends to <or=20 degrees on nonstressed supine bends; and 3) thoracic kyphosis of <or=60 degrees. Fourteen patients were treated with posterior transpedicular instrumented fusion from 1989 to 1993 (none treated with anterior discectomy). Fourteen patients were treated with anterior, single, solid rod instrumented fusion from 1993 to 1996. SRS 22 was performed after surgery in 12 of 14 patients from the posterior group (average 9.2 years) and in 14 of 14 patients from the anterior group (average 5.1 years).
RESULTS: Posterior: The average age was 14.8 years (range 12-17.8 years). Curve correction at average 6.5 years (range 4.0-10.9 years) was 75%. The average lower instrumented vertebra was L3.1. There were no complications. Twelve of 14 patients completed SRS 22 at an average of 9.2 years (range 6.2-10.9 years). Domain scores for Pain, Self-Image, Function, Mental Health, Satisfaction, and Total were 3.8, 4.1, 4.0, 3.8, 4.5, and 4.1, respectively. Anterior: The mean age was 14.5 years (range 12.5-16.5 years). Curve correction at average 4.8 years (range 2.3-7.6 years) was 63% (instrumented segment 89%). The average lower instrumented vertebra was L2.6. Complications included one intercostal neuritis that resolved with suture removal, one broken inferior screw that healed with some loss of correction, and one pseudarthrosis treated successfully with posterior fusion. Fourteen of 14 patients completed SRS 22 at an average of 5.3 years (range 2.0-7.6 years). Domain scores for Pain, Self-Image, Function, Mental Health, Satisfaction, and Total were 4.1, 4.3, 4.4, 4.0, 4.5, and 4.3, respectively. There were no statistically significant differences in any of the domains or the Total score, although there was a trend toward improved function in the patients treated anteriorly. The follow-up was statistically longer in the posterior group.
CONCLUSION: At an average of 9 years of follow-up, patients treated with posterior transpedicular instrumentation have equivalent patient-based outcomes to patients treated with anterior single solid rod instrumentation at an average of 5 years of follow-up.