Perioperative Ketamine in Opioid-Tolerant Patients Undergoing Lumbar Spine Surgery
Condition: Opioid Dependence; Chronic Pain
MeSH terms: Chronic Pain; Opioid-Related Disorders
Intervention: Ketamine; Placebo Comparator
Intervention description: Intraoperative ketamine and post operative 48 hour ketamine infusion with a standardized general anesthesia protocol.; Participants will receive a 1 mg/kg dose of intravenous saline 15 minutes after induction of general anesthesia. Thereafter, a continuous infusion of 0.20 mg/kg/hr saline with a maximum dose of 20 mg/hr will be run to conclude at 48 hours after the end of the surgery (fascial closure)
Intervention MeSH terms: Ketamine
Phase: Phase 2
Study type: Interventional
Primary purpose: Treatment
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Prospective, Randomized, Double-Blind, Placebo Controlled trial involving opiate-dependent patients undergoing lumbar spine surgery
Masking: Triple (Participant, Care Provider, Investigator)
Enrollment: 1.0
Sex: All
Minimum age: 18 Years
Maximum age: 70 Years
Healthy volunteers: No
Keywords: Ketamine; Lumbar Spine Surgery; Opioid Tolerant

Summary:

      The goal of this study is to determine whether comprehensive perioperative administration of
      the N-methyl-D-aspartate (NMDA) receptor antagonist ketamine can increase postoperative pain
      tolerance and reduce opiate consumption in chronic back pain patients undergoing spinal
      laminectomy/fusion when compared to placebo

      Opioid dependence will be defined as daily opioid use (2 or more doses per day) for a period
      of two-months or longer. Intraoperatively, patients will receive a 1 mg/kg dose of
      intravenous ketamine or saline with 15 minutes after induction of general anesthesia.
      Thereafter, a continuous infusion of 0.20 mg/kg/hr ketamine with a maximum dose of 20 mg/hr
      or saline will be run to conclude at 24 hours after the end of the surgery (fascial closure).
      The primary outcome measure will be hydromorphone PCA usage during the first 72 hours
      postoperatively. Secondary outcome measures will be VAS pain scores at rest and with movement
      in PACU, 24 hr, 48 hr, 72 hr, 2 week (post-op visit), 6 week follow-up visit, as well as,
      McGill Pain Questionnaire, Pain Catastrophizing Scale, and emotional distress surveys
      assessing depression and anxiety at preop/screening, postop and 6 week follow-up (PROMIS
      Emotional Distress-Anxiety Short Form, PROMIS Emotional Distress-Depression Short Form), as
      well as a Neuro-QOL Short Form v1.1 - Satisfaction with Social Roles and Activities .
    

Eligibility criteria:

        Inclusion Criteria

          -  Patients undergoing lumbar, thoracic or cervical spine surgery of at least one level,
             and no more than 6 levels.

          -  Patients with chronic back pain (>3 months)

          -  Anaesthetic risk assessment (ASA) 1-3

          -  Opiate-dependent with daily opiate use for at least 2 months and regimented daily
             narcotic dose twice a day/bis in die (BID) or greater or use of a regimented opioid
             pump

        Exclusion Criteria

          -  Intolerance or known allergy to ketamine

          -  History of increased intraocular pressure (> 22mmHg)

          -  Uncontrolled hypertension (systolic blood pressure greater than or equal to 180,
             diastolic blood pressure greater than equal to 100)

          -  Increased intracranial pressure

          -  History of psychosis

          -  Pregnancy

          -  Patients with significant liver disease {signs and symptoms of liver injury, such as
             discolored skin and eyes that appear yellowish, abdominal pain and swelling, Itchy
             skin that doesn't seem to go away, dark urine color, pale stool color, bloody or
             tar-colored stool, chronic fatigue, nausea, loss of appetite, with or without elevated
             Liver Function Tests (LFTs): aspartate aminotransferase (AST) > 120 IU/ml, alkaline
             phosphatase (AP) >130 IU/ml, and alanine aminotransferase (ALT) >40 IU/ml}

          -  Patients with exposure to Cytochrome P450, family 3, subfamily A (CYP3A) and / or
             Cytochrome P450 Family 2 Subfamily B Member 6 (CYP2B6) inhibitors, including the herbs
             and the over-the-counter compounds (list of drugs can be found at
             http://www.fda.gov/drugs/developmentapprovalprocess/developmentresources/druginteracti
             onslabeling/ucm093664.htm)