Reduction versus fusion in situ for isthmic spondylolisthesis: a systematic review and meta-analysis

Isthmic spondylolisthesis impacts up to 11.5% of the general population. For patients who have failed conservative therapy, decompression and fusion or decompression alone are options for surgical management. However, there remains debate as to whether reduction of mobile spondylolisthesis is integral to good patient outcomes. The present systematic review and meta-analysis aimed to address this by comparing clinical and radiological outcomes between patients treated with fusion in situ and those undergoing fusion with reduction of isthmic spondylolisthesis.

The Scopus, EMBASE, Medline, and Cochrane databases were systematically queried on the basis of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to identify studies comparing treatment outcomes in patients with isthmic spondylolisthesis after in situ fusion or fusion with spondylolisthesis reduction. Endpoints of interest included Oswestry Disability Index (ODI) score, hospitalization duration, operative morbidity, and rates of surgical revision. Data from individual studies were aggregated using random-effects models to assess combined effects.

Of 277 identified studies, 7 studies were included with an aggregate 308 patients (143 underwent fusion in situ and 165 underwent reduction). Patients who underwent reduction for isthmic lumbar spondylolisthesis had significantly lower rates of pseudarthrosis at last follow-up (OR 0.22, p = 0.03). Estimated blood loss, operative time, hospitalization duration, change in ODI score, change in back pain (visual analog scale [VAS]), and reoperation rate did not differ significantly between groups.

For patients with isthmic spondylolisthesis, the present data suggest that fusion with reduction of spondylolisthesis may lower rates of pseudarthrosis as compared to in situ fusion. However, operative morbidity and improvement in patient-reported outcomes were similar between strategies.