Dorsal instrumentation for idiopathic adolescent thoracic scoliosis: rod rotation versus translation

The radiographic and clinical outcomes and complications among two groups of adolescent patients treated for idiopathic thoracic scoliosis with dorsal instrumentation using a unified implantation system (Universal Spinal System) were compared retrospectively. A total of 69 patients were included in the study. In 30 patients an intraoperative correction of the scoliosis was performed by translation and segmental correction (translation group, Helsinki). In 39 patients the correction was achieved according to the Cotrel-Dubousset rod rotation maneuver (rod rotation group, Berlin). The goal of the present study is to investigate whether one of the operative procedures leads to a better correction of idiopathic adolescent thoracic scoliosis than the other. The mean follow-up interval was 30 months, with a minimum of 12 months. There were no significant preoperative differences in age (15+/-2 years in both groups), gender, or type of scoliosis (King types 2, 3, and 4). The preoperative radiographic measurements showed no significant differences between the two groups. In both patient groups, the thoracic primary curve, the lumbar secondary curve and the thoracic apical rotation were improved by the operation. Lumbar apical rotation and the sagittal profile were unchanged in both groups. The thoracic primary curve was corrected from 50 degrees +/-6 degrees to 24 degrees +/-7 degrees in the translation group and from 54 degrees +/-11 degrees to 220 degrees +/-11 degrees in the rod rotation group. The extent of the correction of the thoracic curve was significantly greater in the rod rotation group than in the translation group (59% vs. 52% correction). In contrast, the translation procedure seems to have a more beneficial effect on spinal balance than rod rotation. Neurological complications did not occur. In both patient groups an increase in the non-instrumented lumbar curve was noted, in two cases each. In three patients from the rod rotation group the instrumentation had to be removed due to a late infection with negative microbiological results.