A prospective evaluation of pulmonary function in patients with adolescent idiopathic scoliosis relative to the surgical approach used for spinal arthrodesis.

Study Design: A prospective evaluation of pulmonary function in patients with adolescent idiopathic scoliosis undergoing surgical correction.

Objectives: 1) To evaluate prospectively, at regular intervals, the changes in pulmonary function after surgical arthrodesis of primary thoracic and double primary thoracic-lumbar (double major) types of adolescent idiopathic scoliosis in a homogeneous population; 2) to compare the changes in pulmonary function after surgical correction relative to the surgical approach used for spinal arthrodesis; and 3) to determine if short- to midterm morbidity with respect to pulmonary function is associated with the type of surgical approach used for spinal arthrodesis.

Summary Of Background Data: The effect of surgical correction on the pulmonary function of patients with adolescent idiopathic scoliosis is controversial. Studies have shown improvement, decline, or no change in pulmonary function after surgical correction of idiopathic scoliosis.

Methods: Ninety-eight patients with adolescent idiopathic scoliosis undergoing surgical treatment at the authors' institution were prospectively evaluated with pulmonary function tests assessing volume (forced vital capacity and total lung capacity) and flow (forced expiratory volume in 1 second). Pulmonary functions were evaluated before surgery and after surgery at 3 months, 1 year, 2 years, and at the final follow-up visit. All patients were divided into four groups depending on the surgical approach used for spinal fusion: Group 1 (n = 47) underwent a posterior spinal fusion with iliac crest bone graft; Group 2 (n = 33) underwent a posterior spinal fusion with rib resection thoracoplasty; Group 3 (n = 7) underwent an anterior spinal fusion with a rib resection thoracotomy; and Group 4 (n = 11) underwent a combined anterior and posterior spinal fusion with autogenous rib and iliac crest graft used, respectively.

Results: Patients in Group 1 had improved pulmonary function values at 3 months after surgery, whereas patients in Groups 2, 3, and 4 showed a decline at 3 months after surgery. Two years after surgery, Group 1 had significantly improved pulmonary function values (P < 0.0001), whereas the pulmonary function values of patients in Groups 2, 3, and 4 had returned to preoperative values.

Conclusions: 1) Patients with chest cage disruption during surgical treatment showed a decline in pulmonary function at 3 months after surgery. 2) In contrast, patients without chest cage disruption showed an improvement in pulmonary function at 3 months after surgery. 3) Irrespective of the surgical approach used for spinal arthrodesis, postoperative pulmonary function tests (absolute values) returned to preoperative values at 2 years after surgery. 4) Patients who had no chest cage disruption experienced a significantly greater improvement in two of their pulmonary function values at 2 years after surgery than patients with chest cage disruption.