The clinical feature analysis for the emerging scoliosis following resection of congenital hemivertebra

English Keywords:Congenital scoliosis  Hemivertebra  Emerging scoliosis  Hemivertebra resection  Complications  Short fusion

English Abstract:

  【Abstract】 Objectives: To analyze the clinical feature and treatment principle of emerging scoliosis(ES) after posterior hemivertebra resection and short segmental fusion. Methods: From January 2008 to January 2017, 168 patients with single-hemivertebra congenital scoliosis had received posterior hemivertebra resection and short segmental fusion in our department. 12 cases in these patients were found the ES occurred in the follow-up, and the diagnostic criteria were: (1)the Cobb angle increased more than 20° after operation; (2)the apical vertebra was far away from the fusion level[more than 2 levels above the upper instrumented vertebra(UIV) or below the lower instrumented vertebra(LIV)]; (3)without hemivertebra incomplete resection or fixation failure. There were 4 males and 8 females in these 12 cases of ES, with the mean age of 11.8±3.2 years(5-15 years, 2 patients under 10 years old while 10 patients between 10 to 15 years old), mean follow-up time of 34.0±10.0 months(18-50 months), mean fusion levels of 2.7±1.0(2-5). Their general and radiographic data, such as standing full spine AP and lateral X-films, were collected and measured in the study. The parameters included main curve Cobb angle, compensatory curve Cobb angle, ES Cobb angle, segmental kyphosis angle, and proximal junction kyphosis angle. Results: Eight of the twelve patients with ES had a hemivertebra in thoracolumbar spine while the other four in thoracic spine. After initial correction, the mean scoliosis Cobb angle significantly decreased from 36.1°±14.4°(21.8°-69.0°) to 8.9°±8.5°(0°-19.5°)(P=0.000), with a correction rate of 75.3%. The mean kyphosis angle significantly decreased from 25.9°±12.8°(15.5°-40.2°) to 9.5°±4.3°(4.0°-14.7°)(P=0.014). ES was found in 5 patients at 3 months after operation, while in 7 cases at 6 months after operation. The levels of ES were the same as preoperative compensatory scoliosis in 7 of the 12 patients. For the treatment, 5 of the 12 patients received observation: 1 case with progression of ES received revision, 4 cases had no marked progression(from average 25° to 32°) in 25 months(18-36 months) follow-up; 7 of the 12 patients received brace therapy: 3 cases with scoliosis progression received revision surgery, 4 cases with improvement of ES(from average 34° to 23°) in follow-up of 36 months(24-42 months). 4 of the 12 patients received revision operation after failure of observation or brace therapy(Cobb angle >45° and became structural). In an average of 22.5 months(12-36 months) follow-up, their ES had been corrected from 52°(45°-64.2°) to 13°(0°-25°). None of the 4 cases developed secondary deformity. Conclusions: The incidence of ES is about 7% after posterior hemivertebra resection and short segmental fusion. The thoracolumbar hemivertebra(T11-L1) and patient′s age at the time of surgery(adolescence) may be the risk factor for ES. ES progresses relatively fast and should obey the step by step treatment principle as observation, brace and corrective operation.