Single level versus multi-level lumbar interbody fusion for lumbar degenerative diseases: a systematic review and meta analysis

Single-level fusion may offer a more favorable perioperative profile than double- or multi-level constructs, including lower revision risk, shorter operative time, reduced blood loss, shorter hospitalization, and fewer screw loosening events in pooled analyses. However, complications did not differ significantly between groups. Given substantial heterogeneity for perioperative outcomes and generally low to very low certainty of evidence, these findings should be interpreted cautiously and individualized to patient pathology and surgical context.