Primary thoracoplasty and pedicle screw instrumentation in thoracic idiopathic scoliosis

Abstract

Thoracoplasty in combination with spine fusion is an established method to address the rib cage deformity in idiopathic scoliosis. Most reports about thoracoplasty and scoliosis correction focused on Harrington or CD instrumentation. We report a retrospective analysis of 21 consecutive patients, who were treated with pedicle screw instrumentation for idiopathic thoracic scoliosis and concomitant thoracoplasty. Minimal follow up was 24 (24–75) months. Indication for thoracoplasty was clinical rib prominence of more than 15°. In average there was a 44% correction of clinical rib hump, from 18 (15–25°) to 10° (0–18°) (p<0.0001) and a 40% correction of radiological rib hump, from 15 (5–20°) to 9°(2–15°) (p<0.0001). The preoperative pulmonary function, accessed by forced vital capacity (FVC) and one-second forced expiratory volume (FEV1), remained unchanged at the last follow up. The distal end of fusion was the end vertebra of the curve in 83.3% and the end vertebra plus one in 16.7% of the patients. There was a 68% correction of instrumented primary thoracic curves, from 60 (45–85°) to 19°(5–36°) (p<0.0001), and a 45% correction of non-instrumented secondary lumbar curves, from 40 (28–60°) to 22°(8–38°) (p<0.0001). Apical vertebral rotation (AVR) of the thoracic curves improved 54%, from 24 (10–35°) to 11° (5–20°) (p<0.0001). The tilt of lowest instrumented vertebra (LIV) improved 68%, from 28 (20–42°) to 9°(3–20°) (p<0.0001). There was no significant change in sagittal profile of the spine. Analysis with SRS-24 questionnaire showed that the majority of the patients were very satisfied with the outcome. A matched control group (n=21) operated by the same surgeon with the same operation technique but without concomitant thoracoplasty was chosen for comparison. The scoliosis correction in the two groups was comparable. The patients without thoracoplasty had 37% spontaneous improvement of the clinical rib hump.