To retrospectively analyze the efficacy and feasibility of internal fixation of the posterior intervertebral bone graft fusion for ankylosing spondylitis(AS)complicated with thoracic Andersson lesion(AL).

From January 2008 to June 2014, the data of 15 consecutive patients suffering AS complicated with different levels of thoracic Andersson lesion treated by internal fixation of the posterior intervertebral bone graft fusion were analyzed retrospectively. All the patients completed follow-up of at least 2 years. The clinical manifestations, preoperative and postoperative MRI, CT and X-ray examination of the spinal were collected for analysis; Kyphosis angle, sagittal vertical axis(SVA), Oswestry disability index (ODI) and degree of postoperative CT vertebral bone graft fusion were measured.

All patients were operated successfully, the postoperative results were satisfactory. The average kyphosis angle decreased from 51.7 ° to 32.2 °; The average sagittal balance improved from 85.7 mm preoperatively to 45.1 mm of follow-up, the mean ODI improved from 54.9% preoperatively to 21.9% of follow up. After follow-up, the effect of kyphosis correction was good. CT showed thoracic Adersson lesion obtain good bony fusion.

Internal fixation of the posterior intervertebral bone graft fusion surgery can get good fusion, partly correct protrusion deformity, it is a safe and effective treatment of ankylosing spondylitis (AS) of complicated with thoracic Andersson lesion.

Ankylosing spondylitis; Thoracic; Andersson lesion; Posterior internal fixation; Intervertebral bone graft; Osseous fusion