Reduction of Slippage Influences Surgical Outcomes of Grade II and III Lumbar Isthmic Spondylolisthesis.

OBJECTIVE

To explore influence of reduction of slippage on radiologic parameters, clinical outcomes, and perioperative complications in treatment of grade II/III lumbar isthmic spondylolisthesis.

METHODS

We divided 156 patients with grade II/III spondylolisthesis into 2 groups with preoperative balanced or unbalanced pelvis. We further divided each group into group A with postoperative grade I or less slippage and group B with persistent grade II/III slippage postoperatively. Outcome scores were measured for clinical evaluation. Radiologic parameters included pelvic incidence, sacral slope, pelvic tilt, and lumbar lordosis.

RESULTS

In group A patients with preoperative balanced pelvis, lumbar lordosis significantly decreased from 60.2° ± 10.6° to 50.9° ± 9.8° after operation (P < 0.05). In group A patients with preoperative unbalanced pelvis, pelvic tilt decreased from 29.1° ± 8.6° to 24.1° ± 9.1°, and sacral slope increased from 36.1° ± 9.0° to 41.3° ± 8.4°, significantly (P < 0.05). There were significant differences (P < 0.05) between group A and B in postoperative visual analog scale for low back pain (1.5 ± 0.8 vs. 2.1 ± 0.9), Oswestry Disability Index (13.8 ± 8.7 vs. 18.1 ± 7.6), and EuroQol-5 dimensions (0.75 ± 0.14 vs. 0.68 ± 0.11) scores in patients with preoperative unbalanced pelvis.

CONCLUSIONS

In patients with grade II/III lumbar isthmic spondylolisthesis, if postoperative slippage was grade I or less, pelvic tilt and sacral slope could be corrected more effectively, and better clinical outcomes would be obtained for cases with preoperative unbalanced pelvis. In cases with balanced pelvis, lumbar lordosis could be better corrected by the same degree of reduction, although clinical outcomes would not be influenced significantly. Perioperative complications would not be influenced by reduction of slippage.