Effect of Liposomal bupivacaine and ropivacaine on postoperative opioid usage for ultrasound-guided transversus abdominis plane blocks in laparoscopic colorectal resections: a randomized controlled study

The aim was to examine how liposomal bupivacaine (LB) affects the amount of opioids used in patients undergoing laparoscopic colorectal resection following ultrasound-guided transversus abdominis plane (TAP) blocks. The LB group comprised 38 patients, the ropivacaine group comprised another 38 patients. The LB group administered bilateral TAP blocks containing 20 ml of 0.665% LB in each block, the ropivacaine group administered bilateral TAP blocks containing 20 ml of 0.25% ropivacaine in each block. After surgery, the amount of opioids taken, and pain levels were documented at serial intervals—6, 24, 48, and 72 h. The length of the post-surgical hospital stay was also documented. The LB group reported a significant decrease statistically in opioid use at 24 h (24 [22.8–27.3] μg vs. 26 [24–30] μg; P = 0.021) and 48 h (47.5 [44–52] μg vs. 50 [47.5–56] μg; P = 0.043) after surgery compared to the ropivacaine group, however the differences were below the clinically meaningful threshold of 10 μg. Pain intensity at rest and during movement was also statistically lower in the LB group at 24 h and 48 h (all P < 0.05), but the differences did not reach the minimal clinically important difference of 1 point on the VAS scale. The LB group had a shorter postoperative hospital stay (6.2 ± 1.1 days vs. 7.1 ± 2.1 days; P = 0.032). LB for bilateral TAP blocks reduced statistically cumulative opioid consumption and pain scores at 24 h and 48 h postoperatively compared with ropivacaine in patients with laparoscopic colorectal resections. However, the observed differences did not reach the predefined thresholds for clinical significance. Therefore, LB does not provide clinically superior analgesia over ropivacaine in this setting. The potential benefit of LB in reducing hospital stay requires further validation.