1. Receives epidural infusion
2. Receives epidural and ketamine infusions

The patient and study staff are blinded.

This study requires multiple visits to Hospital for Special Surgery in New York City over the course of three months and concludes with a final visit after six months. The study will only cover costs associated with the scheduled in-patient and out-patient visits. The study patient will be responsible for all other costs (including travel and hotel accommodations) that he/she may incur for participating in this study.

• Drug: Ketamine Infusion + Epidural Infusion
  The ketamine and epidural infusions will be administered over 96 hours with appropriate titration.
  Other Names:

  • Ketamine
  • Epidural
• Drug: Control Group + Epidural infusion
  The saline and epidural infusions will be administered over 96 hours with appropriate titration.
  Other Name: Epidural
• Drug: Ketamine Booster Infusion
  Patients will receive three ketamine booster infusions over the course of three months.
  Other Name: Ketamine
• Drug: Control Group Booster Infusion
  Patients will receive three saline booster infusions over the course of three months.
  Other Name: Saline

• Experimental: Ketamine Infusion + Epidural Infusion + Booster Infusion

  Inpatient: Patients will receive a subanesthetic continuous intravenous infusion of KETAMINE 500mg/500ml in 0.9% Sodium Chloride with an epidural infusion.

  Outpatient: Patients will receive three ketamine booster infusions over the course of three months.

  Interventions:

  • Drug: Ketamine Infusion + Epidural Infusion
  • Drug: Ketamine Booster Infusion
• Placebo Comparator: Control Group + Epidural Infusion + Booster Infusion

  Inpatient: Patients will receive a subanesthetic continuous intravenous infusion of SALINE 500mg/500ml in 0.9% Sodium Chloride with an epidural infusion.

  Outpatient: Patients will receive three saline booster infusions over the course of three months.

  Interventions:

  • Drug: Control Group + Epidural infusion
  • Drug: Control Group Booster Infusion

• 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