Surgical Treatment of Main Thoracic Scoliosis with Thoracoscopic Anterior Instrumentation

Background: The surgical outcomes in patients with scoliosis at two years following anterior thoracoscopic spinal instrumentation and fusion have been reported. The purpose of this study was to evaluate the results at five years. Methods: A consecutive series of forty-one patients with major thoracic scoliosis treated with anterior thoracoscopic spinal instrumentation was evaluated at regular intervals. Prospectively collected data included patient demographics, radiographic measurements, clinical deformity measures, pulmonary function, an assessment of intervertebral fusion, and the scores on the Scoliosis Research Society (SRS-24) outcomes instrument. Perioperative and postoperative complications were recorded. Patient data for the preoperative, two-year, and five-year postoperative time points were compared. In addition, a univariate analysis compared selected two-year radiographic, pulmonary function, and SRS-24 data of the study cohort and those of the patients lost to follow-up. Results: Twenty-five (61%) of the original forty-one patients had five-year follow-up data and were included in the analysis. Between the two-year and five-year follow-up visits, no significant changes were observed with regard to the average percent correction of the major Cobb angle (56%+/- 11% and 52%+/- 14%, respectively), average total lung capacity as a percent of the predicted value (95%+/- 14% and 91%+/- 10%), and the average total SRS-24 score (4.2 +/- 0.4 and 4.1 +/- 0.7). Radiographic evaluation of intervertebral fusion at five years revealed convincing evidence of a fusion with remodeling and trabeculae present at 151 (97%) of the 155 instrumented motion segments. No postoperative infections or clinically relevant neurovascular complications were observed. Rod failure occurred in three patients, and three patients required a surgical revision with posterior spinal instrumentation and fusion. Conclusions: Thoracoscopic anterior instrumentation for main thoracic idiopathic scoliosis results in five-year outcomes comparable with those reported previously for open anterior and posterior techniques. The radiographic findings, pulmonary function, and clinical measures remain stable between the two and five-year follow-up time points. Thoracoscopic instrumentation provides a viable alternative to treat spinal deformity; however, the risks of pseudarthrosis, hardware failure, and surgical revision should be considered along with the advantages of limited muscular dissection and improved scar appearance.