Effect of Preemptive Intramuscular Diclofenac on Minimal Effective-Dose Bupivacaine Saddle Block for Minor Perianal Surgeries

Effective control of post-operative pain is an issue that has been repeatedly emphasized and has received an increasing amount of attention in the past few years (1, 2). Opioids, despite their side effects, are still the main cornerstone in managing acute postoperative pain (3). Preemptive analgesia refers to the administration of effective analgesia prior to surgical trauma. The main mechanism of preemptive analgesia is desensitization of the central nervous system and prevention of pain before its onset. (3). Non-opioid preemptive analgesics are commonly used to increase analgesic efficacy and patient satisfaction as well as to reduce opioid consumption and side effects. Saddle anesthesia is a selective spinal anesthesia that is commonly used for perianal surgeries (4-7).

Investigators previously performed a prospective up-down sequential allocation study to evaluate the minimum effective dose of hyperbaric bupivacaine that is needed for inducing a satisfactory and reliable saddle block for perianal surgeries that was restricted to the most caudal spinal nerve roots (S4-coccygeal) that supply the perianal region (8). Although the block produced no motor block in the lower limbs (thus allowing early ambulation), rapid sensory recovery resulted in early request of analgesia and increased opioid consumption. In this prospective, randomized, double blinded, placebo controlled clinical trial, Investigators hypothesize that a single dose of IM diclofenac administered before spinal anesthesia, will decrease postoperative pain, and delay and reduce postoperative analgesic requirement in patients undergoing minor perianal surgeries under minimal effective-dose bupivacaine saddle block