Transversus Abdominis Plane Blocks With and Without Dexamethasone: A Randomized Clinical Trial in Minimally Invasive Colorectal Surgery

Advances in minimally invasive surgery have reduced postoperative morbidity and enhanced recovery. Despite increased use of minimally invasive techniques, postoperative pain remains a challenging aspect of surgical treatment of colorectal diseases and is typically treated with multimodal analgesia, yet the backbone of analgesia continues to be opioid therapy. As analgesics, opioids are effective but fraught with side effects, including delay in return of bowel function, sedation, and potential for dependency.

Minimally invasive colorectal surgery has dramatically improved postoperative outcomes, resulting in significantly shorter length of stay, pain, and overall cost. Despite the advances in multimodal analgesia and enhanced-recovery pathways, the optimal strategy for perioperative analgesia has not yet been defined, and there may be a role for expanded use of regional anesthesia in minimally invasive surgery.

Regional anesthesia, specifically the transversus abdominis plane block, has been shown to reduce postoperative pain and opioid requirements even in the context of minimally invasive surgery. Surgeon-performed, laparoscopically placed TAP blocks are equivalent, or perhaps superior, to ultrasound-guided TAP blocks . Long-acting local anesthetics, specifically liposomal bupivacaine, have been shown to prolong the effect of TAP blocks over non-liposomal bupivacaine , and has also suggested a reduced length of stay and less overall cost, despite the high cost of the formulation. These findings suggest improved outcomes can be expected if a longer block is achieved.

Liposomal bupivacaine is not available and Canada and is very costly. Regional anesthetic supplemented with dexamethasone, a potent corticosteroid, has shown improved efficacy and prolonged duration of anesthetic in other regional anesthetic techniques. The investigators hypothesize that addition of dexamethasone to bupivacaine can prolong the duration of block to be similar to that achieved with liposomal bupivacaine, but at a much lower cost.

Ample evidence exists validating TAP block as an effective adjunct to minimally invasive surgery. Robust data also support the additional benefit of dexamethasone in regional anesthesia. No studies have been published specifically assessing any benefit of combining dexamethasone with local anesthetic to improve the TAP block, and none can be found registered at clinicaltrials.gov. This will be the first such trial to evaluate a promising technique that could reduce postoperative pain and opioid requirements. If found to be effective, this technique would profoundly impact surgical practice around the world.