Resolution of pelvic obliquity after correction surgery for congenital scoliosis

Abstract

Objective To investigate resolution of pelvic obliquity after spinal correction surgery for congenital scoliosis and explore predictor factors of correction of pelvic obliquity after surgery. Methods A retrospective study was performed on congenital scoliosis (CS) patients who underwent scoliosis correction surgery in our hospital from March 2000 to May 2016. A total of 352 patients received correction surgery for scoliosis. According to inclusion criteria and exclusion criteria, 21 CS patients with pelvic obliquity and without leg inequality were included. Of the 21 patients, 9 were males and 12 were females. The mean age was (13.2±10.2) years (range 4 to 36 years). 10 patients were diagnosed as hemivertebrae, 7 as unsegmentation and 4 mixed. 6 CS patients received posterior correction surgery for scoliosis without any osteotomy. 10 received posterior instrumentation and posterior vertebral column resection. 5 received posterior instrumentation and pedicle subtraction osteotomy. The following parameters were measured at pre- and postoperative standing full spine X-ray radiographs: Cobb angle of major curve, trunk shift (TS), pelvic obliquity angle (POA), L5 obliquity angle (L5OA), and lumbar-sacral angle (LSA). Bivariate correlation analysis was conducted to investigate radiographic factors related to correction of pelvic obliquity after surgery. Results Preoperative Cobb angle of major curve improved from 63°±27° to 37°±18° after surgery. Preoperative trunk shift decreased from (42±31) mm to (21±11) mm after surgery. Preoperative pelvic obliquity angle decreased from 16°±7° to 7°±4° after surgery. Preoperative L5 obliquity angle decreased from 23°±11° to 10°±5°after surgery. Preoperative lumbar-sacral angle decreased from 12°±6° to 7°±4° after surgery. The differences of preoperative and postoperative radiographic parameters were statistically significant. Preoperative POA was not correlated to preoperative Cobb angle of major curve, but positively Cobb angle of major curve correlated to preoperative TS, L5OA, and LSA. The difference of pre- and postoperative POA were positively correlated to the differences of pre- and postoperative Cobb angle of major curve, TS, L5OA, and LSA. Conclusion Scoliosis correction surgery could effectively level pelvic for patients with congenital scoliosis and pelvic obliquity. L5OA and LSA could be predictors for pelvic obliquity after scoliosis correction surgery. Key words: Scoliosis; Pelvis; Radiography