EVALUATING ANALGESIC INTERVENTIONS FOR ACUTE SURGICAL PAIN, PREVENTION OF PERSISTING POST-SURGICAL PAIN, AND CHRONIC LOW BACK PAIN

Abstract

Acute and chronic pain conditions cause significant patient distress, interference with daily activities, and increased health care costs. It is important to evaluate analgesic interventions to improve pain relief, function, quality of life, and also to prevent persisting pain after surgery. This thesis is a combination of studies evaluating analgesic interventions in the setting of acute surgical pain; prevention of persistent post-surgical pain; and chronic low back pain. In part 1, we report our comparison of morphine and hydromorphone in 402 ambulatory surgery patients, for their ability to achieve satisfactory analgesia with minimal emesis using a design of multicentre randomized controlled trial. We observed no differences in their analgesic potential and common side effects and note that appearance of side effects is likely to be idiosyncratic. In part 2, we report our 2×2 factorial feasibility trial to prevent persistent post-surgical pain in patients having elective video-assisted thoracic surgery lobectomies, comparing N-methyl-D-aspartate antagonists versus placebo, and intravenous steroids versus placebo. As our feasibility outcomes were not met, we suggest appropriate considerations for protocol changes before embarking on a definitive larger trial. In part 3, we report on our systematic review and meta-analysis assessing the effectiveness and safety of gabapentinoids (gabapentin and pregabalin) in adult patients with chronic low back pain. We observed that the existing evidence is small and there is minimal improvement in pain and other outcomes with potential for adverse events. We suggest that the use of gabapentinoids for chronic low back pain merits caution and there is need for large high-quality trials.