OBJECTIVETo investigate the clinical effect and indication of bone graft and impaction on posterior interbody fusion for lumbar instability.

METHODSFrom January 2001 to July 2008, 95 patients with lumbar instability were treated by bone graft and impaction on posterior interbody fusion. Including 41 males and 54 females, the age from 45 to 76 years old with an average of 59 years. There were 68 cases with single level, 22 cases with two-level, 5 cases with three-level in patients, which were 127 intervertebral space altogether. The neural canal and affected side nerve root were decompressed thoroughly during operation. Resected the disc from the affected side and erased the cartilage to plate extensively combined with pedicle screw fixation, and impaction on interbody fusion with the excisional vertebral plate bone was achieved. To assess the improvement of the patients' symptom, sign, and JOA scores pre and post operatively. Meanwhile, the changes of intervertebral height from the lumbar radiographs were measured and the degrees of interbody bone fusion were evaluated according to SUK method.

RESULTSAll the 95 patients were followed up from 12 to 90 months with the mean of 44.8 months. All the clinical symptom were improved significantly or disappeared completely. All the 127 intervertebral space achieved good bone fusion. There was no displacement of bone graft and severe complication happened. According to the radiograph, all the intervertebral heights were increased obviously. The mean JOA score improved from 11.3 +/- 3.3 preoperative to 25.1 +/- 2.8 at 8 weeks postoperative; achieved 24.8 +/- 3.2 with followed up at the last time (P < 0.001).

CONCLUSIONBone graft and impaction on posterior interbody fusion was one of the most effective methods for the lumbar instability. It has extensive range of application, and it's suitable for senile lumbar degeneration instability especially.