The Impact of Posterior Intervertebral Osteophytes on PROMs Following L5-S1 ALIF and TLIF

Study Design. Retrospective cohort study Objective. (1) To develop a reliable grading system to assess the severity of posterior intervertebral osteophytes and (2) to investigate the impact of posterior intervertebral osteophytes on clinical outcomes following L5-S1 decompression and fusion via anterior lumbar interbody fusion (ALIF) and minimally-invasive transforaminal lumbar interbody fusion (MIS-TLIF). Summary of Background Data. There is limited evidence regarding the clinical implications of posterior lumbar vertebral body osteophytes for ALIF and MIS-TLIF surgeries and there are no established grading systems that defines the severity of these posterior lumbar intervertebral osteophytes. Methods. A retrospective analysis of patients undergoing L5-S1 ALIF or MIS-TLIF was performed. Preoperative and postoperative patient-reported outcome measures (PROMs) of Oswestry Disability Index (ODI) and Leg Visual Analog Scale (VAS) at 2-week, 6-week, 12-week, and 6-month follow-up time points were assessed. Minimal clinically important difference (MCID) for ODI of 14.9 and VAS leg of 2.8 were utilized. Osteophyte grade was based on the ratio of osteophyte length to foraminal width. “High-grade” osteophytes were defined as a maximal osteophyte length greater than 50% of the total foraminal width. Results. 70 consecutive patients (32 ALIF, 38 MIS-TLIF) were included in the study. There were no significant differences between the two cohorts in PROMs or achievement of MCID for Leg VAS or ODI preoperatively or at any follow-ups. On multivariate analysis, neither the surgical approach nor the presence of high-grade foraminal osteophytes were associated with leg VAS or ODI scores at any follow-up timepoint. Additionally, neither the surgical approach nor the presence of high-grade foraminal osteophytes were associated with achievement of MCID for leg VAS or ODI at 6 months. Conclusion. ALIF and MIS-TLIF are both valid options in treating degenerative spine conditions and lumbar radiculopathy, even in the presence of high-grade osteophytes that significantly occupy the intervertebral foramen. Level of Evidence. 3