The Correlation Between Restoration of Lumbar Lordosis and Surgical Outcome in the Treatment of Low-grade Lumbar Degenerative Spondylolisthesis With Spinal Fusion.

STUDY DESIGN

Retrospective clinical study.

OBJECTIVE

To investigate the relationship between the restoration of the lumbar lordosis (LL) and the surgical outcome of patients undergoing spinal fusion for low-grade lumbar degenerative spondylolisthesis.

SUMMARY OF BACKGROUND DATA

Correlation between low back pain and the loss of LL in the treatment of low-grade lumbar degenerative spondylolisthesis has seldom been reported.

METHODS

Between May 2005 and July 2011, 59 patients with low back pain and neurogenic claudication due to low-grade lumbar degenerative spondylolisthesis underwent spinal decompression and fusion by a senior surgeon. Ten patients were lost to follow-up. The mean age of the remaining 49 patients (10 men and 39 women) was 64.0 years (range, 47-88 y). Patients were categorized on the basis of the spino-pelvic posture: type 1 [pelvic incidence (PI)<45 degrees] (n=12), type 2 (45 degrees≤PI≤60 degrees) (n=24), and type 3 (PI>60 degrees) (n=13). The LL restoration ratio was calculated by the actual LL divided by the predicted LL. The clinical results were evaluated using a visual analogue scale and the Oswestry Disability Index. Postoperative 36-inch spinal films were used to assess the sagittal balance.

RESULTS

The mean follow-up period was 43.2 months (range, 28-62 mo). Forty-eight patients showed significant improvement with respect to visual analogue scale and Oswestry Disability Index regardless of whether the LL was restored higher or lower. Postoperative 36-inch spinal films showed the C7 plumb line to be within an average of 4.4 cm (range, 0.6-5.6 cm) from the posterior-superior corner of the S1 vertebrae.

CONCLUSIONS

Patients with smaller PI tended to be restored higher, and those patients with a larger PI were more likely to be restored lower. For patients with normal sagittal balance, the surgical outcomes in the treatment of low-grade lumbar degenerative spondylolisthesis with spinal fusion are not correlated with restoration of the LL.