Decompression Alone Versus Fusion for L4-5 Degenerative Spondylolisthesis with Translational Motion

Introduction: Studies have been conducted comparing the outcomes of decompression alone and fusion in degenerative lumbar spondylolisthesis (DLS); however, there is little data regarding such comparison in cases with translational motion.

Methods: This retrospective cohort study included patients who underwent minimally invasive decompression or fusion for L4-5 DLS with translational motion >2 mm and had a minimum of 1-year follow-up. The following outcome measures were compared between the decompression and fusion groups: 1) patient-reported outcome measures (PROMs) (ODI; VAS back and leg; SF-12 PCS), 2) minimal clinically important difference (MCID), 3) patient acceptable symptom state (PASS), and 4) response on the global rating change (GRC) scale. Two postoperative timepoints were analyzed – early ( < 6 months) and late (>6 months).

Results: 84 patients with translation >2 mm were included, out of which 60 (71%) underwent fusion. The decompression group had significantly higher average age compared to fusion (70.9 vs. 64.8 years, p=0.001). There was no significant difference in the average translational motion between the two groups (decompression 2.9 mm, fusion 2.8 mm; p=0.704). There was no significant difference between the groups in other demographic variables and preoperative PROMs. Both groups showed significant improvement in PROMs at < 6 and >6 months compared to preoperative with no significant difference in the magnitude of improvement. Most patients achieved MCID for PROMs (>50%) and PASS (decompression 67%, fusion 74%; p=0.61) in both groups at both timepoints with no significant difference in the achievement rates between the two groups. >80% of patients reported feeling better on the GRC scale at both timepoints with no significant difference in the responses between the two groups. There were no significant differences between the decompression and fusion groups in the intraoperative or in-hospital complication and reoperation rates.

Conclusion : Minimally invasive decompression alone might lead to similar outcomes as fusion in patients with DLS and translational motion >2 mm, up to 2 years. However, future research with larger sample size and longer follow-up is required to establish these findings.