Use of Perioperative Pain Blocks In Urological Surgery: A Phase III Randomized Single Blind Single Center Three Arm Non-inferiority Trial

Currently, ultrasound-guided transversus abdominis plane (UTAP) blocks (regional anesthetic blocks) are being employed for the care of urological surgery patients. Local and regional anesthesia is commonly used throughout surgical fields. However, ultrasound-guidance can be challenging, particularly in larger, obese patients. It is unknown how such techniques compare to laparoscopic-guided blockade, with respect to time to perform, learning curve, and postoperative analgesia. The transversus abdominis plane lies deep within the abdominal wall, potentially allowing for greater ease of access from a laparoscopic approach from within than the ultrasound guided percutaneous approach.

Prior randomized studies have been completed comparing UTAP and Placebo. In 2012 Hosgood et al. compared UTAP and placebo (UTAP w/ saline) in 46 live-donor laparoscopic nephrectomy patients (24 UTAP vs. 22 placebo). Pain control (measured using the 0-10 VAS scale) was greater on post-operative day (POD) 1 in patients receiving UTAP than in controls, 19 (15) vs. 37 (20) (presented as mean (SD)), respectively. A similar randomized study in 2014 compared UTAP and placebo (UTAP w/saline) in 21 hand assisted laparoscopic nephrectomy patients (10 UTAP vs. 11 placebo). The study was initially powered for 50 patients but with decreased accrual secondary to a surgeon taking a leave of absence during the study period. Pain scores were recorded using the 0-10 VAS score. Postoperatively at 24 hours (median (IQR)) UTAP patients demonstrated decreased postoperative pain than placebo patients (1 (0-2) vs. 4 (2-6)) on the VAS score, respectively.

A larger study, done in 2016, with 80 randomized patients undergoing retroperitoneal laparoscopic urologic surgery compared UTAP (40) and saline UTAP (40). Pain scores were assessed using the 0-100 VAS score scale. On POD1, UTAP group had lower pain scores (mean (SD)) of 8.4 (5.9) vs. placebo 28.3 (12.2).

The most recent study, done in 2018, examined 100 randomized patients undergoing robotic-assisted laparoscopic prostatectomies. Fifty patients were given UTAP blocks while the others received no block. A Numerical Rating Scale (assumed to range from 0-10 as not otherwise specified) was used to assess pain. Patients receiving the block at 24 hours had better pain control (mean (SD)) (1.8 (0.82) vs. 3.57 (0.64)).

While all of these studies point to potential efficacy of UTAP, no data has been published to date comparing laparoscopic administration of the TAP block (LTAP) to ultrasound guided administration. While these regional anesthetic blocks carry a theoretical risk of hematoma or damage to surrounding structures, none of the above studies report any complications with the injections.