Prospective pulmonary function comparison of anterior spinal fusion in adolescent idiopathic scoliosis: Thoracotomy versus thoracoabdominal approach

STUDY DESIGN. Prospective clinical study of a retrospective database. OBJECTIVE. To compare the prospective pulmonary function changes following anterior spinal instrumentation and fusion through an open thoracotomy with the same procedure through a thoracoabdominal approach at 2 years follow-up. SUMMARY OF BACKGROUND DATA. Open anterior spinal instrumentation and fusion for adolescent idiopathic scoliosis (AIS) has been known to decrease pulmonary function after surgery. However, the differential effect of an open thoracotomy versus thoracoabdominal approach on pulmonary function in AIS is unknown. METHODS. Sixty-four AIS patients who underwent an anterior spinal instrumentation and fusion through an open thoracotomy (TC group) for a major main thoracic scoliosis were compared with 55 patients who underwent the same procedure through a thoracoabdominal approach (TA group) for a major thoracolumbar/lumbar (TL/L) scoliosis using pulmonary function tests assessing forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) before surgery and 2 years after surgery. The TC group was divided into 2 groups, TC group with thoracoplasty (1-5 ribs, n = 35) and TC group without thoracoplasty (n = 29). RESULTS. Preoperative and 2-year postoperative absolute FVC in the TC group averaged 3.05L and 2.74L, respectively (0.31L decrease, P < 0.0001) versus 3.27L and 3.21L, respectively (0.06L decrease, P = 0.15) in the TA group. The TC group demonstrated a significantly larger decrease in absolute FVC at 2 years postoperative (P < 0.0001). Preoperative and 2-year postoperative absolute FEV1 in the TC group averaged 2.56L and 2.35L, respectively (0.21L decrease, P < 0.0001) versus 2.82L and 2.81L, respectively (0.02L decrease, P = 0.67) in the TA group. The TC group demonstrated a significantly larger decrease in absolute FEV1 at 2 years postoperative (P = 0.001). TC patients with thoracoplasty (n = 35) demonstrated a similar average decrease (0.34L) of absolute FVC at 2 years postoperative compared with those without thoracoplasty (0.26L, P = 0.49) and a similar average decrease of absolute FEV1 at 2 years postoperative (0.23L vs. 0.19L without thoracoplasty, P = 0.76). CONCLUSION. An open thoracotomy approach for treating a main thoracic curve demonstrated a significant decrease in the absolute pulmonary function tests values at 2 years postoperative while the thoracoabdominal approach for treating a TL/L curve did not.