Correction of deformity from convexity in adolescent idiopathic scoliosis

Correction of scoliosis deformity from the convexity of the curve reduces the theoretical risk of neurovascular injury, a fact to be considered, especially in the paediatric population. Our aim is to evaluate the efficacy of this technique in patients with adolescent idiopathic scoliosis (AIS).

This is a retrospective study, in which 50 patients with AIS were included. The minimum required follow-up was 24 months. After open posterior approach and flexibilisation of the deformity by facetectomies, pedicle screws were inserted 'free-hand' in the convexity and at the extremes of the assembly at the concavity level, with intraoperative neurophysiological monitoring. In situ moulding maneuvers, segmental correction of the curve by compression-distraction and direct vertebral derrotation from the convexity were performed, using another chromium-cobalt rod on the concave side. General demographic and deformity data were collected, as well as radiological variables.

Fifty patients with AIS underwent surgery. The mean operative time was 251±50 min. Mean blood loss was 4.3±0.3 g/dL Hb. The mean postoperative stay was 6.3±0.3 days. A reduction of the Cobb angle was achieved in primary curve by 64.4% (from 53.0°±12.6° to 18.9°±9.5°; P<0.001) and in secondary curve by 47% (from 33.3°±11.4° to 17.5°±9.5°; P=0.005). Coronal balance changed from 3.6±1.9 to 2.3±4.2 mm (P=0.59) and sagittal vertical axis (SVA) changed from -14.7±40 to -6.1±28.9 mm (P=0.10). There were no vascular complications. A single intraoperative neurophysiological event was recorded, requiring screw repositioning. Two wound infections were recorded.

Correction of the deformity from the convexity using low-density constructs with pedicle screws, achieves similar results to other techniques.