Randomized Controlled Trial of Ketamine Infusion With Continuous Epidural Infusion for Treatment of Complex Regional Pain Syndrome

INCLUSION CRITERIA: * Patients must meet the Budapest CRPS criteria, including two or more symptom categories and three or more sign categories (as previously documented by a pain management physician or neurologist, or as observed on initial neurologic examination by the study investigator) * Patients must have trialed at least three of the following therapies without relief judged adequate by the patient: * Anti-depressants * Anti-seizure medication * Muscle relaxants * Nerve blocks (somatic or sympathetic) * Non-opioid analgesics * Non-steroidal anti-inflammatory drugs * Opioid analgesics * Physical therapy * Spinal cord stimulator trial * Patients of either gender between the ages of 18 and 65 inclusive * Patient report of a NRS pain score of at least 5 in at least two out-patient pain management physician clinic visits EXCLUSION CRITERIA: * Patients younger than 18 or older than 65 * Patients who: * Are pregnant * Are affected with glaucoma * Are affected with thyrotoxicosis * Are lactating * Are on chronic anticoagulation therapy * Have autonomic dysfunction with hemodynamic instability * Have cardiac rhythm disturbance * Have cerebrovascular disease * Have conditions that would preclude central line placement * Have conditions that would preclude epidural catheter placement * Have congestive heart failure * Have coronary artery disease * Have creatinine level above 1.5 * Have electrolyte disturbance * Have had previous reaction to IV contrast dye * Have history of deep vein thrombosis * Have history of systemic administration of ketamine for the treatment of pain * Have liver disease * Have known history of psychosis, significant thought disorder, or untreated (bipolar disorder depression or anxiety disorder ok) * Have uncontrolled hypertension * Any patient who is unable to provide consent due to cognitive difficulties * Non-English speakers, as some of the instruments are only validated in English * Patients with active litigation or workers compensation related to CRPS * Patients with an intolerance or allergy to any medication planned as a component of the study * Patients with known history of illegal drug use or alcohol dependence