Clinical Evaluation of GENEX® DS in Instrumented Posterolateral Fusion

Inclusion Criteria: * Men or women 18-75 years of age * Have ability to understand the requirements of the study, to provide written informed consent, and to comply with the study protocol * Have a spinal condition of the lumbar spine (L1-S1) requiring instrumented posterolateral fusion at one or two levels Exclusion Criteria: * Patients undergoing instrumented fusion for trauma, tumor, psuedoarthrosis, or same- - level recurrent stenosis * Patients where placing graft material on both sides (posterolateral gutters) is not possible, for example in the case of a complete facetectomy * Patients requiring instrumented fusion in the cervical or thoracic spine * Extraspinal cause of back pain such as trauma, infection, instrumentation failure, or neoplasm * Severe degenerative bone disease * Hypercalcemia * Active local or systemic infection * Morbid obesity defined as BMI \> 40 * Patients who are pregnant / able to become pregnant and not following a reliable contraceptive method * Uncooperative patients who can't or won't follow post-operative instructions including individuals who abuse drugs or alcohol * Anatomy or other factors that prohibit safe surgical access to the surgical site * Allergy or sensitivity to any component of the treatment procedure * Inadequate tissue coverage over the operative site * Inadequate bone stock or bone quality * Fever or leukocytosis * Uncorrectable coagulopathy or hemorrhagic diathesis * Uncontrolled diabetes * Severe vascular disease or cardiopulmonary conditions that present prohibitive anesthesia risk * Neuromuscular disease or disorder * Mental illness * Has an active workman's compensation lawsuit