Correlation between intervertebral disc injury and postoperative kyphosis after percutaneous kyphoplasty for osteoporotic thoracolumbar fracture

Abstract

Objective To investigate the correlation between intervertebral disc injury and postoperative kyphosis after percutaneous kyphoplasty (PKP) in patients with single-level osteoporotic thoracolumbar fracture. Methods The data of 63 patients were retrospectively analyzed who had been treated at Department of Orthopaedics, Puai Hospital for single-level osteoporotic thoracolumbar fractures from August 2012 to August 2015. They were all treated with posterior balloon dilatation PKP. According to the preoperative MRI data, they were divided into an observation group (29 patients with intervertebral disc injury) and a control group (34 patients without intervertebral disc injury). The wedged angles (WA) and cobb angles of the injured vertebrae were compared between the 2 groups at postoperative 1, 6 and 12 months. The changes in WA and cobb angles were observed in the same group at postoperative 1, 6 and 12 months. The cob angles in the patients with different Sander classifications of intervertebral disc injury in the observation group were observed at postoperative 1, 6 and 12 months. The correlation between intervertebral disc injury and postoperative kyphosis after PKP was statistically analyzed. Results The 2 groups were comparable as there were no significant differences between them in preoperative general data (P>0.05). All the patients were followed up for an average of 19.3 months (from 12 to 30 months). The WAs at postoperative 1, 6 and 12 months in the observation group (4.9°±2.5°, 5.8°±2.4° and 6.2°±2.4°) were insignificantly larger than those in the control group (4.7°±2.4°, 5.2°±2.4° and 5.8°±2.4°) (P>0.05). The cobb angles at postoperative 6 and 12 months in the observation group (14.4°±3.6° and 15.8°±3.5°) were significantly larger than those in the control group (10.1°±3.7° and 10.7°±3.8°) (P 0.05). At postoperative 1, 6 and 12 months in the observation group, the cobb angles for patients with Sander types Ⅱ&Ⅲ were significantly larger than for patients with Sander type Ⅰ (P<0.05). Conclusion After PKP for patients with single-level osteoporotic thoracolumbar fracture, kyphosis of different severities may occur after operation; intervertebral disc injury is an important factor which aggravates postoperative kyphosis. Key words: Intervertebral disc; Osteoporosis; Vertebroplasty; Thoracolumbar fractures