Does obesity affect surgical outcomes in adolescent idiopathic scoliosis?

Study Design. A retrospective review of surgical outcomes in adolescents with idiopathic scoliosis. Objective. To determine if an association exists between body mass and surgical outcomes in adolescent idiopathic scoliosis ( AIS). Summary of Background Data. Obesity has reached epidemic proportions globally. In adults, obesity increases the likelihood of developing multiple medical co-morbidities and has been associated with an increased incidence of perioperative complications. The effect of obesity on surgical outcomes in the treatment of AIS patients has not been studied previously. Methods. Radiographic measures, perioperative data, and Scoliosis Research Society Outcomes scores were collected on surgically treated AIS patients. The body mass index ( BMI) was calculated for each patient and normalized to sex and age ( BMI %). Analysis of variance was used to identify differences between healthy weight ( BMI % < 85) and overweight patients ( BMI % >= 85). The data were checked for normality and equal variances, and the level of significance was set at 0.01. Results. Two hundred forty-one patients ( 204 women, 37 men; 14.3 +/- 2.0 years) with a minimum of 2-year follow-up met the inclusion criteria for this study. The average BMI ( kg/m(2)) was 20.7 +/- 3.7 ( BMI % average: 54.5, range: 1 - 99). No significant differences were found between the overweight ( n = 48) and healthy weight ( n = 193) patients with regards to surgical time, estimated blood loss, major Cobb percent correction, maintenance of correction, rate of implant failure, pseudarthrosis, and surgical revision. However, the preoperative thoracic kyphosis was significantly greater in the overweight group ( 27.0 degrees +/- 12.6 degrees) compared with the healthy weight patients ( 21.8 degrees +/- 12.5 degrees) ( P = 0.004). Conclusion. Overweight adolescents ( BMI % >= 85) had a their healthy weight peers. Body mass, however, did not affect the ability to achieve coronal or sagittal scoliotic deformity correction, and did not increase perioperative morbidity or mortality. These findings were either influenced by the small sample size of this cohort, or because the comorbidities responsible for increased perioperative complications in adults, had not yet developed in this adolescent population.