Effects of Concomitant Decompression Adjacent to a Posterior Lumbar Interbody Fusion Segment on Clinical and Radiologic Outcomes: Comparative Analysis 5 Years After Surgery

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To examine the effects of concomitant decompression adjacent to the posterior lumbar interbody fusion (PLIF) segment on the clinical and radiological outcomes 5 years after surgery. METHODS: Forty-five consecutive patients who had undergone L3/4 decompression with L4/5 PLIF for multilevel stenosis with degenerative spondylolisthesis (DS), and were followed for 5 years, were enrolled (group D). As a control group, 45 age-, sex- and preoperative disc height at L3/4–matched patients who had undergone L4/5 PLIF alone for L4/5DS were randomly selected (group A). Disc height, vertebral slippage, range of motion, posterior opening angle, segmental lordotic angle, presence of the intradiscal vacuum phenomenon (IVP) at the L3/4 level were measured on radiographs. Japanese Orthopaedic Association (JOA) score and the requirement for additional L3/4 surgery were evaluated. RESULTS: In terms of pre-/postoperative radiographic changes between the groups, significant differences were detected regarding disc height narrowing of ≥3 mm (group D 31%, group A 9%) and IVP (group D 33%, group A 11%). There were no significant differences in other radiological parameters. The recovery rate of the JOA score (group D 58%, group A 61%) and reoperation rate (group D 2.2%, group A 6.7%) were not significantly different between the groups. CONCLUSION: Concomitant decompression adjacent to the PLIF segment accelerated adjacent disc degeneration compared to PLIF alone, but it did not predispose to the development of instability 5 years after surgery. Moreover, the JOA score and reoperation rate were not significantly different between groups D and A.