Video-Assisted Thoracoscopic Spinal Fusion Compared with Posterior Spinal Fusion with Thoracic Pedicle Screws for Thoracic Adolescent Idiopathic Scoliosis

Abstract

Although the gold standard for the surgical treatment of thoracic adolescent idiopathic scoliosis has been posterior spinal fusion, video-assisted thoracoscopic surgery recently has become a viable alternative. In the treatment of structural thoracic curves, video-assisted thoracoscopic surgery has demonstrated outcomes equivalent to those of posterior spinal fusion with use of an all-hook or hybrid pedicle screw-hook construct. No study to date, however, has compared this technique with posterior spinal fusion with thoracic pedicle screws, which has become the current standard of care. A matched-pair analysis of thirty-four consecutive patients (seventeen pairs) undergoing either video-assisted thoracoscopic surgery or posterior spinal fusion with thoracic pedicle screws for the treatment of structural scoliosis was performed; the study included eight male and twenty-six female patients with an average age of 15.0 years. Pairs were matched according to curve type and magnitude, patient age, and sex. Clinical data, the results of the Scoliosis Research Society questionnaire, and radiographic data were collected preoperatively and at a minimum of two years postoperatively and were compared between the groups. Video-assisted thoracoscopic surgery was associated with significantly increased operative times (mean, 326 compared with 246 minutes; p = 0.033) and reduced blood loss (mean, 371 compared with 1018 mL; p = 0.001), but there were no differences between the groups in terms of the transfusion rate (18% compared with 29%; p = 0.69) or the length of stay. The percentage correction of the major curve was 57.3% for the video-assisted thoracoscopic surgery group and 63.8% for the posterior spinal fusion group (p = 0.08). With the numbers available, no differences were detected in terms of the cephalad thoracic curve, caudad compensatory lumbar curve, coronal balance, thoracic kyphosis, lumbar lordosis, sagittal balance, end vertebra tilt angle, or angle of trunk rotation measurements preoperatively or at the time of the latest follow-up. The average number of fused levels was 5.9 in the video-assisted thoracoscopic surgery group and 8.9 in the posterior spinal fusion group (p < 0.001). Relative to the Cobb end vertebra, the most caudad instrumented vertebra was 0.81 level more cephalad in the video-assisted thoracoscopic surgery group as compared with the posterior spinal fusion group (p = 0.004). No significant differences were detected in any of the questionnaire outcomes at any time point. Although both groups experienced similar improvement from baseline in terms of pulmonary function at two years, the posterior spinal fusion group had significantly improved peak flow measurements (p = 0.04) in comparison with the video-assisted thoracoscopic surgery group. For single thoracic curves of <70 degrees in patients with a normal or hypokyphotic thoracic spine, video-assisted thoracoscopic surgery can produce equivalent radiographic results, patient-based clinical outcomes, and complication rates in comparison with posterior spinal fusion with thoracic pedicle screws, with the exception that posterior spinal fusion with thoracic pedicle screws may result in better major curve correction. The potential advantages of video-assisted thoracoscopic surgery over posterior spinal fusion with thoracic pedicle screws include reduced blood loss, fewer total levels fused, and the preservation of nearly one caudad fusion level, whereas the disadvantages include increased operative times and slightly less improvement in pulmonary function.