This study will be a prospective, open-label, multi-center study that will collect additional safety and efficacy data for the minimally invasive PerQdisc Nucleus Replacement Device (NRD). Patients will have degenerative disc disease (DDD) in one or more lumbar discs. The NRD is used for surgical replacement of a single nucleus pulposus between spinal lumbar discs L1-S1 using any standard anterior, standard lateral, or minimally invasive posterolateral surgical approach. Currently the surgical gold standard involves spinal fusion of the affected vertebral bodies, reducing range of motion and increasing stress on other vertebral bodies. The goal of nucleus replacement is to reduce chronic low back pain by maintaining disc height while preserving range of motion.