A Comparison of Intra-op Ketamine vs Placebo in Patients Having Spinal Fusion

About This Study

Postoperative pain is severe after major spine surgery. Opioids such as morphine and hydromorphone are routinely used for postoperative pain control. These drugs have significant side effects, most importantly respiratory depression, nausea, constipation and tolerance. Moreover, many spine surgery patients have used opioid pain medication for back pain long term, leading to pre-surgical opioid tolerance and increased postoperative pain. This has led to a search for adjuvant medications to reduce the use of opioids and reduce opioid mediated side effects and tolerance. Ketamine is an intravenous anesthetic with analgesic properties in subanesthetic doses. Ketamine is a noncompetitive antagonist of N-methyl-D-aspartate (NMDA) receptors. NMDA receptors are involved in central pain sensitization via wind-up phenomenon and altered pain memory, a process which can be blocked by ketamine. NMDA receptor antagonists may prevent the development of tolerance to opioids and hyperalgesia. Ketamine has been safely used to decrease pain in numerous studies. Ketamine can also act as an antidepressant with hours of administration. Ketamine has rapid brain uptake and subsequent re-distribution with a distribution half-life of 10-15 minutes and an elimination half-life of 2 hours. Ketamine does not cause respiratory depression.

Conditions Studied

Interventions

• •Ketamine
• •Placebo

Eligibility

Inclusion Criteria:

1. Adult (\>/=18)
2. male or female
3. Undergoing surgery for multilevel (\>2 level) spinal fusion from a posterior approach.
4. General anesthesia
5. English speakers such that they can complete the pain score and satisfaction questionnaires whose scores are a critical outcome variable.
6. If female, subject is non-lactating and is either: a. Post-menopausal or post hysterectomy; b. Of childbearing potential but is not pregnant at time of baseline as determined by pre-surgical pregnancy testing.
7. Subject is American Society of Anesthesiologists (ASA) physical status 1, 2, or 3.

Exclusion Criteria:

1. Cognitively impaired (by history)
2. Subject with a history of psychosis
3. Subject known to have significant hepatic disease
4. Subject for whom opioids or ketamine are contraindicated
5. Patients with narrow angle glaucoma
6. Increased intracranial or intraocular pressure
7. If female, is either pregnant or lactating.

Study Locations (1)