[Factors affecting adjacent segment degeneration after rigid lumbar internal fixation].

OBJECTIVE

To analyze the factors affecting the occurrence of adjacent segment degeneration (ASD) after lumbar internal fixation.

METHODS

The clinical data of 147 surgical patients with lumbar disc herniation, lumbar spinal stenosis and lumbar spodylolisthesis undergoing surgeries between January 2002 and July 2007 in our hospital were reviewed. The correlations of gender, range of fixation, position of fixation, and characteristic of the adjacent disc to the occurrence of ASD were analyzed.

RESULTS

The patients were followed up for a mean of 30-/+10 months (18-84 months). The incidence of ASD was 13.6% in these patients, occurring all at the cephalad adjacent segment. The presence of preoperative degeneration of the adjacent disc gave rise to increased risk of ASD following the surgery (chi(2)=6.272, P=0.012), and multivariate analysis indicated that preoperative adjacent disc degeneration was a risk factor for postoperative ASD (P=0.046), but gender, range of fusion and site of fusion were not the risk factors.

CONCLUSION

Presence of adjacent segment degeneration before the operation is associated with a significantly increased risk of postoperative ASD.