Date of Award


Degree Type

Selective Evidence-Based Medicine Review

Degree Name

Master of Science in Health Sciences - Physician Assistant


Physician Assistant Studies

Department Chair

John Cavenagh, MBA, PhD, PA-C


Objective: The objective of this selective EBM review is to determine whether or not posterior lumbar interbody fusion (PLIF) is a superior surgical intervention compared to posterolateral fusion (PLF) for treating patients younger than 65 years old with isthmic lumbar spondylolisthesis who have failed 6 months of conservative therapy.

Study Design: Systemic review of three English language primary studies comparing the efficacy of PLF and PLIF surgical approaches for isthmic lumbar spondylolisthesis published after 2006.

Data Sources: Three randomized controlled trials published after 2006 selected from PubMed based on their relevance to the proposed question.

Outcomes Measured: The outcomes measured in the trials focused on Oswestry Disability Index (ODI) scores reported by the patients indicating the level of lower back pain they were having prior to and after the completion of the surgery.

Results: All three studies confirmed that both PLF and PLIF surgical interventions for isthmic lumbar spondylolisthesis in patients 65 years or younger who failed 6 months of conservative therapy showed improvement over the pre-operation baseline. Two of the studies indicated that there was no difference in terms of long term pain relief (1+ years post-operation) when performing PLF versus PLIF; however, one of the studies indicated that PLF showed statistically significant reduction in pain long term. One of the studies also showed that pain levels 3 months post operation were lower with PLIF compared to PLF.

Conclusions: Both PLF and PLIF are surgeries that can reduce the lower back pain felt by patients with isthmic lumbar spondylolisthesis. The results of the review indicate that there is no clear evidence as to which surgical approach is superior in terms of decreasing lower back pain in patients after surgery. Other factors such as surgeon experience and preference for performing these procedures along with patient anatomy should continue to guide surgeons in deciding the most appropriate approach to surgical repair for isthmic lumbar spondylolisthesis.