Pulmonary function after thoracoplasty in the surgical treatment of adolescent idiopathic scoliosis.

ABSTRACT

STUDY DESIGN: Retrospective case series review. OBJECTIVE: To compare two similar groups of adolescents surgically treated for their spinal deformity either by posterior segmental fusion alone (PSF) or by posterior spinal fusion and thoracoplasty (PSF+T); attention was focused on the long-term effects of thoracoplasty on pulmonary function in the surgical treatment of adolescent idiopathic scoliosis. SUMMARY OF BACKGROUND DATA Posterior spinal arthrodesis with thoracoplasty and an open anterior approach, with respect to a posterior only fusion have been found to have a deleterious effect on pulmonary function for as long as five years postoperatively after surgical treatment of adolescent idiopathic scoliosis. METHODS: A group of 40 consecutive adolescent patients, surgically treated between 1998 and 2001 by posterior spinal fusion and thoracoplasty, was compared with a similar cohort of 40 adolescents treated in the same period by posterior segmental fusion alone. Pedicle screw instrumentation alone and a minimum five-year follow-up were requested as inclusion criteria. Both a radiographic analysis and a chart review was performed, evaluating the pulmonary function tests (PFTs), the SRS-30 score questionnaire and the Lenke classification system. A radiographic Rib Hump (RH) assessment was also performed. RESULTS: The entire series was reviewed at an average clinical follow-up of 8.3 years. There were no statistically significant differences between the two groups in terms of gender, age (PSF+T 16.3 y vs. PSF 15.2 y), Lenke curve type classification and preoperative Cobb's main thoracic (MT) curve magnitude (PSF+T 66° vs. PSF 63°), whereas both final MT percent correction (PSF+T 53.03% vs. PSF 51.35%; P<0.03), RH absolute correction (PSF+T -2.1 cm vs. PSF -1.05; P<0.01) and RH overall percent correction (PSF+T 55.4% vs. PSF 35.4%; P<0.0001) were greater in the thoracoplasty group. No statistical differences were observed between the two groups in PFTs both pre-operatively and at last follow-up. Nevertheless, comparing preoperative to final PFT'S within each group, only in the PSF group both forced vital capacity and forced expiratory volume in one second showed a statistically significant improvement at final evaluation. At last follow-up visit, the SRS-30 scores did not show any statistical difference between the two groups (total score PSF+T 4.1 vs. PSF 4.3). CONCLUSIONS: Our findings suggest that thoracoplasty did not adversely affect long-term PFTs in AIS patients treated by posterior spinal fusion alone using pedicle screws instrumentation, as already highlighted by previous reports. A trend towards better coronal plane correction and rib hump improvement was seen, although not clearly reported in a self-assessment disease-specific questionnaire.