Intra-operative Ketamine Infusions in Opioid-dependent Patients With Chronic Lower Back Pain

Noxious stimuli occurring intraoperatively and postoperatively generate central sensitization, decreasing pain thresholds and ultimately increasing analgesic requirements. The pathophysiology of central sensitization is thought to involve excitatory amino acid receptors such as N-methyl-d-aspartate (NMDA) (1, 2). Ketamine is a N-methyl-d-aspartate (NMDA) receptor antagonist that has been shown to be useful in the reduction of acute postoperative pain and analgesic consumption in a variety of surgical interventions (3). Spine surgery provides a unique opportunity to evaluate the preemptive and preventative impact of ketamine on the primary end points of postoperative 24 and 48 hour opioid consumption in patients with chronic pain. The goal of this double blinded, prospective, randomized placebo controlled trial is to quantify the preemptive and preventative analgesic effects of ketamine infusions in this patient population. Such insight may lead to better pain control, improved satisfaction, and ultimately a reduction in side-effects related to postoperative opioid use.