Correction of Thoracic Idiopathic Adolescent Scoliosis with Segmental Hooks, Rods, Wisconsin Wires Posteriorly:
It's Bad and Obsolete - Correct?

Washington University, St. Louis, MO, USA

PURPOSE/METHODS: 40 consecutive thoracic idiopathic adolescent curves treated between 1995 and 1998 at one institution were analyzed. All were thoracic curves, no lumbar curves, double major curves, or triple major curves. 6 were double thoracic curves. 6 were false double major curves (King II, Lenke C). Patients were administered pre and postop SRS questionnaires. Radiographs were studied for coronal correction, sagittal correction, junctional deformities 2 segments above/2 segments below, fusion status, loss of correction status, complications, imbalance of curves above and below. Radiographic analysis was by 2 independent observers. All patients were treated with bilateral 5.5 mm CD Horizon instrumentation. Corrective forces were translational and in-situ contouring. The age range was 12-18 (avg. 14). 10 were males, and 30 were females. Posterior fusion and instrumentation was performed 1-2 levels above and 1 level below what would have been performed with anterior fusion and instrumentation. An average of 10 hooks and 4 Wisconsin wires were used for an average of 14 fixation points per 11 segments. All were out of bed on POD#1; none were braced postop. Follow-up was minimum 2 year to maximum 4 year, 3 month, with an average of 3 year, 2 month follow-up.

RESULTS: The average preop thoracic curve was 57º; the average ultimate postop curve was 27º (p=0.0001). In the sagittal plane, T5-T12 averaged 22º preop and 17º postop. Regarding sagittal measurements 2 segments above and 2 segments below, only 1 patient showed a distal change › 10º. This patient was in retrospect fused 1 segment too short. In all cases, the Cobb measurement of the lumbar curve below improved. For the false double major curve patterns, the unfused lumbar curve averaged preop 45º and postop 26º. There were no instances of decompensation to the left and no instances of the left shoulder being higher postop than it was preop. There was one pseudarthrosis with loss of correction in a patient with a double thoracic curve pattern. In this hyperkyphotic patient, the average number of fixation points per segment was ‹ 1:1. In regards to the SRS questionnaires, only 1 patient has demonstrated a lower score postop than preop. Only 2 patients have scored less than 30 out of a possible 45 on the SRS questions 16-24. No patient demonstrated subcutaneous implant prominence. There were no neurologic deficits, no wound infections and no respiratory complications.

CONCLUSIONS/DISCUSSION: 2 complications were related to surgeon error. The most common distal segment fused was L2 and would have been L1 with anterior instrumentation. No proximal junctional deformities occurred. SRS questionnaire data improved pre to postop (p=0.002).

SIGNIFICANCE: Compared to what has been reported for anterior treatment, posterior treatment as described above performed as well or better than anterior instrumentation in all categories except for the number of distal levels saved (the difference being 1 level) and kyphosing of the thoracic curve (+ clinical significance). There were no high left shoulders postop, and treatment was successful for all false double major curves. Perhaps posterior treatment as described above is not obsolete.