A Postmarket Surveillance Study of the Paradigm Spine Dynamic Stabilization System (DSS)

Inclusion Criteria: * Patient is skeletally mature (21-85 years old). * Patient has degenerative spondylolisthesis (Grade 1-3) with objective evidence of neurologic impairment, kyphosis, and/or failed previous fusion (pseudarthrosis) at index level. * Capable and willing to comply with the requirements unique to the study, adhere to the post-operative treatment and management program, and return for required follow-up examinations. * Surgeon has determined that DSS™ System is an appropriate treatment for the patient without regard to the study. Exclusion Criteria: * The need for interbody cages, allograft, or any other assistance during surgery. Device is only to be used with autograft per FDA approved indications. * Any medical, mental or surgical condition precluding the potential benefit of spinal surgery or surgery in general. * Acute or chronic systemic, spinal or localized infections. * Active, severe systemic and metabolic diseases. * Obesity defined as Body Mass Index \> 35. * Subject is pregnant or interested in becoming pregnant in the next 36 months. * Dependency on pharmaceutical drugs, drug abuse, or alcoholism. * Lack of patient cooperation. * Foreign body sensitivity to the implant material. * Degenerative scoliosis greater than 25 degrees. * Grade 4 degenerative spondylolisthesis (\>75% slip). * Significant osteopenia A screening questionnaire for osteopenia, SCORE (Simple Calculated Osteoporosis Risk Estimation), will be used to screen patients who require a DEXA bone mineral density measurement. If DEXA is required\*, exclusion will be defined as a DEXA bone density measured T score of ≤ -1.0 (The World Health Organization definition of osteopenia). * Soft tissue deficit not allowing wound closure. * Congenital abnormalities, tumors or other conditions that would prevent secure component fixation that has the potential to decrease the useful life of the device. * Inadequate pedicles or vertebral body geometry of the thoracic, lumbar and sacral vertebrae. * Bony lumbar spinal stenosis not related to the primary degenerative spondylolisthesis indication. * Pars defect. * Clinically compromised vertebral bodies at affected level due to current or past trauma. * Prisoner or ward of the state. * Currently in litigation regarding a spinal condition. * Known allergy to titanium, titanium alloys, CoCrMo, polyethylene or MR contrast agents. * Is currently involved in a study of another investigational product for similar purpose.