Maximal Pulmonary Recovery After Spinal Fusion for Adolescent Idiopathic Scoliosis How Do Anterior Approaches Compare?

Study Design. Retrospective analysis of prospectively collected data. Objective. To compare the relative rates of pulmonary recovery and maximal pulmonary function with surgical approach. Summary of Background Data. Anterior versus posterior spinal fusion (ASF, PSF) for the treatment of adolescent idiopathic scoliosis (AIS) has been debated. Although procedures that violate the chest wall may compromise pulmonary function, lung function continues to improve after surgery at variable rates depending upon surgical approach. Methods. We reviewed the medical records from one hundred fifty nine AIS patients (age 15.6 +/- 2.2; 113 women; 46 men) treated with spinal fusion from 2003 to 2007 by a single surgeon. Forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and radiographic measurements were evaluated before surgery and at 1, 3, 6, 12, and 24-months follow-up on average. Four surgical groups were compared: PSF, ASF (open thoracoabdominal approach for thoracolumbar curvature), video-assisted thoracoscopic surgical release with instrumentation (VATS-I), and VATS with PSF. FEV1 and FVC were fitted to model to evaluate the immediate postoperative pulmonary function (Yo), maximal recovery (Plateau), and rate (K) of pulmonary improvement. Results. Patients in each surgical subgroup were as follows: PSF (Lenke 1: n = 50, Lenke 2,3: n = 20), ASF (Lenke 5, n = 35), VATS-I (Lenke 1 = 31, Lenke 3 = 1), and VATS + PSF (Lenke1: n = 9, Lenke 2-6: n = 13). Early postoperative pulmonary function was higher with ASF and PSF as compared to both VATS groups (P < 0.05). Comparing all curve types, VATS-I showed a small decline of absolute FEV1 compared to PSF at 2-years follow-up. Comparing thoracic curves, however, no differences in FEV1 or FVC were noted at 6 to 12 months until 2-years follow-up. The rate of recovery (K) was equivalent for all surgical approaches and curve types. Conclusion. Compared to ASF or PSF, VATS procedures showed an initial decline in pulmonary function, which resolved fully by 6- to 12-months follow-up. Modest declines in maximal pulmonary function with VATS-I were seen when comparing all curve types together but not when comparing Lenke 1 curves alone. VATS procedures for thoracic scoliosis and open approaches for thoracolumbar curve types were associated with minimal to no permanent deficits.