TLIF Osteo3 ZP Putty Study (Also Known as the TOP Fusion Study)

Inclusion Criteria: * Subject has been diagnosed with DDD (as defined below), degenerative spondylolisthesis or lumbar spinal stenosis at one spinal level: DDD defined as one or more of the following: instability as defined by greater than or equal to 3 mm translation or greater than or equal to 5 degrees angulation, decreased disc height, on average by greater than or equal to 2 mm, but dependent upon the spinal level, scarring/thickening of ligamentum flavum or annulus fibrosis, herniated nucleus pulposus or vacuum phenomenon. * The subject has failed at least six months of non-operative treatment prior to clinical study enrolment (e.g. bed rest, physical therapy, bracing, traction, drug therapy, etc) and is a candidate for spinal fusion surgery over one vertebral level between, and including, L2 to S1 (i.e. second lumbar to first sacral). * The subject is 40-65 years old. * The subject is, in the Investigator's opinion, psychosocially healthy and physically able to fully comply with this protocol, including the post-operative regimen, required follow up visits, the filling out of required forms, and have the ability to understand and give written informed consent. Exclusion Criteria: * Subject has diagnosis of symptomatic DDD, spondylolisthesis, or lumbar spinal stenosis at more than one level. * Subject has had prior surgery at any lumbar level. * Subject has systemic infection or infection at the surgical site. * History of significant metabolic bone disease such as…