A Comparison of Ultrasound Guided Transversus Abdominis Plane Nerve Block Techniques

Postoperative pain can pose significant challenges in the postoperative recovery of patients undergoing major colorectal surgery. Traditionally, opioids have played an important role in treating postoperative pain. It is well established that opioids are highly effective in relieving pain; however opioids are associated with numerous side effects that include nausea, vomiting, constipation, ileus, bladder dysfunction, respiratory depression, pruritus, drowsiness, sedation, and allergic reaction. These opioid side effects, which range in severity, can significantly interfere with discharge home following colorectal surgery. Significant interest exists in the use of local anesthetic based regional anesthesia techniques as a means to extend the analgesic window for patients undergoing colorectal surgery. Specifically, the use of the transversus abdominis plane (TAP) block as an adjunct in postoperative pain control has been widely reported in the anesthesia and colorectal surgery literature. Historically, the block was performed in a blind fashion with relative success and presently the block is typically performed either with ultrasound guidance or laparoscopic visualization. While TAP block has shown to be effective in post-operative pain control, the techniques used to place the block have not formally been compared. The investigators are purposing a prospective, patient-blinded, randomized study of patients undergoing major colorectal surgery to compare TAP block under ultrasound guidance versus laparoscopic visualization versus no TAP block. The investigators hypothesize that laparoscopic-guided TAP block is non-inferior to ultrasound-guided TAP block with respect to perioperative pain control and either technique is superior to no TAP. In addition the investigators will measure procedural time, any adverse events related to the block, overall postoperative analgesic requirement, analgesic duration, postoperative pain scores, length of postoperative hospital stay