Radiographic outcome of surgical treatment of adolescent idiopathic scoliosis in males versus females

Background: Studies on adolescent idiopathic scoliosis have well documented the differences between natural history of male and female patients. There are also differences in responses to nonoperative treatment, but the results of operative treatment in male patients compared with females have not been widely reported. Only few studies had compared the outcomes of operative treatment between male and female patients with different results. Methods: We retrospectively reviewed the outcome of 150 (112 girls and 38 boys) consecutive patients with diagnosis of adolescent idiopathic scoliosis who were managed surgically between May 1996 and September 2005. Next, male radiographic parameters were compared with female ones pre- and postoperatively. Then, a subgroup of 38 matched girls was compared regarding the age, curve type, curve magnitude, and the instrumentation we used. Results: In comparing male patients with unmatched girls, the boys had greater mean age (17.3 +/- 2.3 vs. 16.3 +/- 2.9; p = 0.049), greater primary curve (71.4 +/- 21.3 degrees vs. 62.7 +/- 17.5 degrees; p = 0.013), less flexibility ( 30.1 +/- 13.5% vs. 40.3 +/- 17.8%; p = 0.01), and less correction percentage (51.3 +/- 12.9% vs. 58.8 +/- 16.5%; p = 0/013). The loss of correction was comparable between the two groups. In the matched comparison, the flexibility in boys was less than girls (30.1 +/- 13.5% vs. 38.1 +/- 17.5%; p = 0.027). Also, the boys had a smaller correction percentage compared to the girls, but this finding was not statistically significant. Conclusion: There was similar distribution curve pattern between male and female patients with AIS. Males had more rigid primary curves compared to females but a similar degree of postoperative scoliosis correction. Male AIS patients were older at the time of surgery. These preoperative gender differences, however; did not compromise the radiological outcomes of surgical treatment and the results were comparable between the genders.