Operative correction of adolescent idiopathic scoliosis in male patients. A radiographic and functional outcome comparison with female patients.

BACKGROUND The outcomes following surgical treatment of adolescent idiopathic scoliosis have traditionally been assessed on the basis of radiographic parameters and, more recently, functional outcome measures. However, we know of no published studies in which radiographic and functional outcomes following surgery were compared between male and female patients. METHODS Fifty-two male patients who had had surgery for adolescent idiopathic scoliosis were compared retrospectively with two groups of female patients: a random sample of 130 female patients who had had surgical treatment for adolescent idiopathic scoliosis during the same time period and a subgroup of fifty-two of these female patients who had been matched to the male patients with regard to curve type and magnitude. Radiographic parameters were compared between the male and female patients, and the Scoliosis Research Society outcome questionnaire was used to compare functional results between the male patients and the matched female group. RESULTS Compared with the random sample of female patients, the male patients were older at the time of presentation (average [and standard deviation], 13.9 +/- 1.9 compared with 12.8 +/- 1.4 years) and at the time of surgery (average, 15.9 +/- 2.0 compared with 14.2 +/- 1.4 years) (p < 0.05). The male and female patients presented with primary coronal curves of similar magnitudes (average, 48 degrees +/- 19 degrees compared with 47 degrees +/- 13 degrees ), but the male patients had larger curves at the time of surgery (average, 62 degrees +/- 11 degrees compared with 56 degrees +/- 10 degrees ) with greater coronal plane imbalance. Compared with the subset of female patients matched for curve type and magnitude, the male patients had, on average, a longer surgical time (263 +/- 61 compared with 202 +/- 40 minutes), greater intraoperative blood loss (1148 +/- 660 compared with 944 +/- 408 mL), and less curve correction in the coronal plane (from 62 degrees +/- 11 degrees to 31 degrees +/- 11 degrees compared with from 59 degrees +/- 10 degrees to 23 degrees +/- 9 degrees ) (p < 0.05). The loss of coronal plane correction, the final coronal balance, all measured sagittal plane parameters, and the prevalence of complications were the same in these two groups. With regard to functional outcome, the scores were similar with the exception that the male patients had lower scores in the category of "function from back condition" when compared with the matched female patients (3.8 +/- 0.2 compared with 4.3 +/- 0.3 points) (p < 0.05). CONCLUSIONS Adolescent idiopathic scoliosis is identified at a later age in male patients than in female patients with similar curve types. The curve magnitudes in the male patients are greater at the time of surgery. When surgeons are planning operative correction of adolescent idiopathic scoliosis in male patients, they should expect longer operative time, greater blood loss, and less coronal plane correction of the primary curve. However, balance in the coronal and sagittal planes should be achieved and complication rates and functional outcomes can be expected to be similar to those in female patients.