Three-dimensional rotations of the thoracic spine after distraction with and without rib resection: a kinematic evaluation of the apical vertebra in rabbits with induced scoliosis.

An experimental model of induced scoliosis in New Zealand rabbits was studied to evaluate the effects of rib resection on the apical vertebra during distraction for scoliosis surgery. After concave distraction, three-dimensional rotations of the apical vertebra were measured using a motion analysis system, which included three cameras and six reflective markers. Distraction with rib resection on the convexity produced minimal rotations in the coronal plane (0.77 degrees), sagittal plane (0.96 degrees), and transverse plane (0.61 degrees) compared with no rib resection. The distraction maneuver with rib resection has no significant effect on derotation of the apical vertebra in the coronal and transverse plane, but slightly greater forward rotation was apparent in the sagittal plane (p < 0.05). Resection of three convex ribs directly corrects the rib prominence and does not seem to improve derotation.