This document discusses lumbar degenerative spondylolisthesis. It begins by covering the phylogenetic evolution of the spine from quadruped to biped posture and how this impacted spinal loading and development. It then reviews recent literature on controversies regarding conservative versus surgical management. Specifically, it summarizes findings from the SPORT, SLIP, and SSSS trials comparing laminectomy alone to laminectomy with fusion. The document concludes by outlining the authors' surgical experience with posterolateral fusion for spondylolisthesis.