Effects of a Spine Navigation System on Op-time and Radiation Exposure

Inclusion Criteria: * Diagnosis of spinal stenosis of the lumbar spine with degenerative spondylolisthesis, all grades, and planning to undergo surgical fusion; * Skeletally mature adults between the ages of 18-85 years at the time of surgery; * Has completed at least 6 months of conservative therapy for degenerative diagnosis, if appropriate; and, * Personally signed and dated an informed consent document prior to any study-related procedures, indicating that the patient has been informed of all pertinent aspects of the study. Exclusion Criteria: * History of malignancy, craniocervical junction pathology, cervical and thoracic locations, and/or previous lumbar operation; * Significant peripheral neuropathy or acute denervation secondary to radiculopathy, caused by conditions other than spinal stenosis; * Significant peripheral vascular disease (defined as diminished dorsalis pedis or tibial pulses); * Morbid obesity, defined as BMI \> 40 kg/m2; * Active systemic or local infection; * Active hepatitis (defined as receiving medical treatment within two years); * Immunocompromised, such as but not limited to being diagnosed with Acquired Immunodeficiency Syndrome (AIDS), HIV infection, Severe Combined Immunodeficiency Syndrome, or Thymic Hypoplasia; * Insulin-dependent diabetes mellitus or any other medical condition(s) that would represent a significant increase in surgical risk or interfere with normal healing; * Immunologically suppressed, or has received systemic steroids, excluding nasal steroids, at any dose daily for \> 1 month within last 12 months; * History of Paget's disease, osteomalacia, or any other metabolic bone disease; * Involved in study of another investigational product that may affect outcome; * Women who are pregnant, lactating or anticipate becoming pregnant within 24 months post-surgery; * Non-English speaking; * Patients who are incarcerated; * Worker's compensation cases; or, * Patients involved in active litigation relating to his/her spinal condition.