Fueling the debate: Are outcomes better after posterior lumbar interbody fusion (PLIF) or after posterolateral fusion (PLF) in adult patients with low-grade adult isthmic spondylolisthesis?

Study design: Retrospective cohort study. Clinical question: Do more adult patients affected by low grade isthmic spondylolisthesis have significant clinical and radiological improvement following posterior lumbar interbody fusion (PLIF) than those who receive posterolateral fusion (PLF)? Methods: One hundred and fourteen patients affected by adult low grade isthmic spondylolisthesis, treated with posterior lumbar interbody fusion or posterolateral fusion, were reviewed. Clinical outcome was assessed by means of the questionnaires ODI, RMDQ and VAS. Radiographic evaluation included CT, MRI, and x-rays. The results were analyzed using the Student t-test. Results: The two groups were similar with respect to demographic and surgical characteristics. At an average follow-up of 62.1 months, 71 patients were completely reviewed. Mean ODI, RMDQ and VAS scores didn't show statistically significant differences. Fusion rate was similar between the two groups (97% in PLIF group, 95% in PLF group). Major complications occurred in 5 of 71 patients reviewed (7%): one in the PLIF group (3.6%), four in the PLF group (9.3%). Pseudarthrosis occurred in one case in the PLIF group (3,6%) and in two cases in PLF group (4.6%). Conclusions: In our series, there does not appear to be a clear advantage of posterior lumbar interbody fusion (PLIF) over posterolateral fusion (PLF) in terms of clinical and radiological outcome for treatment of adult low grade isthmic spondylolisthesis.