Reduction versus In Situ Fusion for Adult High-Grade Spondylolisthesis: A Systematic Review and Meta-Analysis

Background: Surgical management of high-grade spondylolisthesis is controversial. Both reduction and in situ fusion are available options, but it remains unclear which approach provides better outcomes. We conducted a systematic review and meta-analysis of studies reporting outcomes following reduction or in situ fusion for adult high-grade spondylolisthesis.

Methods: PubMed, Embase, Web of Science, and Cochrane databases were last searched on June 24, 2019. We identified 1236 studies after excluding duplicates. After screening, 15 studies were included in the meta-analysis. Random-effects models were used to pool effect estimates.

Results: A total of 188 patients were analyzed. Compared with reduction, in situ fusion had a higher mean estimated blood loss (584 mL vs. 451 mL) and a clinically higher incidence of neurologic (48% vs. 15%), pseudarthrosis (13% vs. 8%), and infectious (20% vs. 10%) complications; however, these differences were not statistically significant. Reduction was associated with a clinically higher incidence of overall complications (32% vs. 25%) and dural tears (22% vs. 7%). Reduction provided better pain relief (mean difference [MD] = 5.24 vs. 4.77) and greater change in pelvic tilt (MD = 5.33 vs. 2.60); however, these differences were not statistically significant. Patients who underwent reduction had significantly greater decline in Oswestry Disability Index scores (MD = 55.7 vs. 11.5; P_interaction < 0.01) and greater change in slip angle (MD = 25.0 vs. 11.4; P_interaction = 0.01).

Conclusions: In management of adult high-grade spondylolisthesis, both approaches appeared to be safe and effective. Reduction appeared to offer better disability relief and spinopelvic parameter correction than in situ fusion.