This prospective, non-comparative, single-center, post-market trial will evaluate the safety and efficacy of the PEEK-OPTIMA ™ HA Enhanced Keos Lumbar Interbody Fusion Device in patients suffering from degenerative disc disease, spondylolisthesis and retrolisthesis in the lumbar spine. The trial will capture clinical outcomes, radiographic and CT outcomes over a 24 month period post operatively. One centre will be involved in the recruitment of 30 patients the clinic involved will focus on this type of treatment.