Rib Hump Deformity Correction in Patients with Adolescent Idiopathic Scoliosis: A Comparison of Three Spinal Fusion Systems.

The aim of the present study is to control the hypothesis that the rib hump deformity can be adequately corrected when applying vertebral derotation. We retrospectively studied patients treated with full pedicle screw systems (group A), hybrid constructs (group B), and Harrington rod instrumentation (group C). No costoplasties were performed in the patients included in our study. Derotation was applied in groups A and B. The rib hump deformity was assessed on lateral radiographic studies by rib index (RI). Of the 72 patients that were finally included in our study, 30 patients (24 females and 6 males; mean age, 14.5 ± 2.2 years) were treated with a full pedicle screw system, 23 patients (19 females and 4 males; mean age, 13.8 ± 1.9 years) were treated with a hybrid construct, and 19 patients (16 females and 3 males; mean age, 14.3 ± 2 years) received the Harrington rod instrumentation. In all groups RI was significantly corrected after surgery. Before surgery no difference in RI was found among groups; however, after surgery RI was found significantly higher in group C as compared to groups A and B. The between-group analysis revealed that the correction of RI, and thereby the rib hump deformity correction, did not significantly differ among the three patient groups. In conclusion, it cannot be suggested based on the present study that vertebral derotation alone can offer an adequate correction of the rib hump deformity. Further, the development of rib cage deformity and its degree of interdependence with the scoliotic spinal deformity has to be further investigated and assessed, as it seems that it may not necessarily result directly from the primary vertebral deformity.