Outcomes Analysis of Patients with Single Torsion Thoracolumbar/Lumbar Scoliosis Treated with Anterior or Posterior Instrumentation: An Average Five to Nine Year Followup

· (c - DePuy Acromed)

University of Kansas Medical Center, Kansas City, KS USA

INTRODUCTION:
Since the advent of single, stiff rod anterior instrumentation, and now dual rod anterior instrumentation, most thoracolumbar and lumbar scoliosis is treated with an anterior approach. We have previously presented a retrospective comparison of patients with single torsion TL/L 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 five years (anterior instrumentation) and nine years (posterior instrumentation).

METHODS:
Inclusion criteria were 1) Single torsion TL or L curve of 70 or less, 2) Thoracic curve bends to 20 degrees or less on non-stressed supine bends, and 3) Thoracic kyphosis of 60 or less. 14 patients were treated with posterior transpedicular instrumented fusion from 1989 to 1993 (None treated with anterior discectomy). 14 patients were treated with anterior, single, solid rod instrumented fusion from 1993 to 1996. SRS 22 was performed post operatively 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 (12-17.8). Curve correction at average 44 months was 78%. The average lower instrumented vertebra (LIV) was L3.1. There were no complications. 12 of 14 patients completed SRS 22 at an average of 9.2 years. Domain scores for Pain, Self Image, Function, Mental Health, Satisfaction, and Total were 3.98, 4.21, 4.17, 3.86, 4.54, and 4.15 respectively. Anterior: The mean age was 14.5 years (12.5-16.5). Curve correction at average 32 months was 63% (instrumented segment 89%). The average lower instrumented vertebra (LIV) was L2.6. There was 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. 14 of 14 patients completed SRS 22 at an average of 4.9 years. Domain scores for Pain, Self Image, Function, Mental Health, Satisfaction, and Total were 4.16, 4.25, 4.44, 3.94, 4.54, and 4.29 respectively. There were no statistically significant differences in any of the domains or the total score, though 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 nine years 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 five years follow-up.