Comparison of posterolateral fusion with and without additional posterior lumbar interbody fusion for degenerative lumbar spondylolisthesis.

OBJECTIVES

The surgical approach that should be used for degenerative spondylolisthesis (DS) is a controversial issue. Decompression and posterolateral fusion (PLF) with or without lumbar interbody fusion is widely used. Many studies have compared the outcomes of these 2 approaches, but the appropriate indications for these approaches are still unclear. The authors retrospectively studied the effects of posterior lumbar interbody fusion (PLIF) after PLF for the treatment of DS.

METHODS

Forty patients who underwent single level decompression and posterior instrumentation for DS at L4-5 and were followed for at least 2 years were retrospectively studied. The patients were divided into 4 groups: the stable PLF group (S-PLF, n=13); the stable PLF with additional PLIF group (S-PLIF, n=11); the unstable PLF group (U-PLF, n=8); and the unstable PLF with additional PLIF group (U-PLIF, n=8). Clinical and radiographic comparisons were carried out between the S-PLF and S-PLIF groups, and between the U-PLF and U-PLIF groups.

RESULTS

Clinical assessments, using the improvements of the Oswestry Disability Index (ODI) and the Visual Analog Scale (VAS), were statistically significantly different between the 2 unstable groups (DeltaU-PLF <DeltaU-PLIF, P(ODI)=0.032, P(VAS)=0.004, respectively). On radiologic assessment, the slip angle increment was significantly different between the 2 stable groups (DeltaS-PLF>DeltaS-PLIF, P=0.029), and the disc height increment was significantly different between the 2 stable groups (DeltaS-PLF<DeltaS-PLIF, P=0.043) and between the 2 unstable groups (DeltaU-PLF<DeltaU-PLIF, P=0.042).

CONCLUSIONS

This study suggests that preoperative segmental instability may be a criterion determining whether an additional PLIF would be beneficial in the treatment of lumbar DS.