Laparoscopic versus ultrasound-guided visualization of transversus abdominis plane blocks (LUV-TAP study)

Background:
Ultrasound-guided (US) transversus abdominis plane (TAP) block is commonly utilized as part of a multi-modal approach for postoperative pain management. In adult patients, surgeon performed laparoscopic guided TAP blocks have been demonstrated to provide equally effective analgesia. This study seeks to determine whether laparoscopic-guided TAP blocks are as efficient as US-guided TAP blocks.

Method:
In this prospective, randomized controlled trial, pediatric patients undergoing laparoscopic procedures were randomly assigned to one of two treatment arms: receiving US-guided TAP block placed by the pediatric regional anesthesiologist (US-arm) versus laparoscopic-guided TAP block placed by the surgeon (LAP-arm). Pre-and post-block US images were obtained and reviewed by blinded anesthesiologists. The primary outcome was PACU pain scores. Secondary outcomes were PACU opioid consumption, time to block completion, accuracy of block, and adequacy of anesthetic spread.

Results:
Forty-eight patients were enrolled, 24 in each arm. In the LAP-arm, 62% of blocks were placed in the correct plane with 72% having adequate spread. In the US-arm, 78% of blocks were placed in the correct plane and 59% had adequate spread. Blocks were completed faster in the LAP-arm (mean±SD minutes: 2.1±1.0 vs. 7.7±3.3, p < 0.001). PACU pain scores were similar between the groups (1.3±1.1 vs. 1.6±1.5, p = 0.50). Opioid consumption was also similar between the LAP and US-arms (4.5±15 vs. 0.9±1.4 morphine milligram equivalents, p = 0.29).

Conclusion:
TAP blocks placed laparoscopically have an equivalent efficacy in terms of post-operative pain scores, narcotic use, tissue plane accuracy and spread when compared with TAP blocks placed under US-guidance. However, TAP blocks placed laparoscopically were faster and may result in less operating room time and less time under general anesthesia for the pediatric patient.