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 followup. 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 degreesr <= 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.