Infiltration of liposome bupivacaine into the transversus abdominis plane for postsurgical analgesia in robotic laparoscopic prostatectomy: a pilot study

BACKGROUND: Transversus abdominis plane (TAP) infiltration has been increasingly used for postsurgical analgesia in abdominal/pelvic procedures; however, duration/extent of analgesia with standard local anesthetics is limited. This pilot study assessed the preliminary efficacy and safety of two volumes of liposome bupivacaine administered via TAP infiltration in patients undergoing robotic laparoscopic prostatectomy. METHODS: In this single-center, open-label, prospective study, patients older than 18 years received TAP infiltration with liposome bupivacaine immediately after surgery. The first 12 patients received a total volume of 20 mL liposome bupivacaine (266 mg); the next 12 received 40 mL liposome bupivacaine (266 mg). The liposome bupivacaine was diluted with 0.9% normal saline. The primary efficacy measure was duration of analgesia, measured by time to first opioid administration. Secondary outcome measures included patient-assessed pain scores, opioid use, and opioid-related adverse events (AEs). RESULTS: Twenty-four patients received liposome bupivacaine (20 mL, n=12; 40 mL, n=12) and were included in the primary analysis. Three refused participation in a 10-day follow-up visit and did not complete the study. Median time to first opioid administration after surgery was 23 and 26 minutes for the 20 and 40 mL groups, respectively. Mean total amount of postsurgical opioids ranged from 25.4 to 27.3 mg; after hospital discharge to day 10, both groups required a mean of 0.7 oxycodone/acetaminophen tablets/day. Mean pain scores of 4.4 and 5.3 were reported at 1 hour and 3.1 and 3.9 at 2 hours postsurgery, with 20 and 40 mL doses, respectively. Neither group had mean scores higher than 3.0 at any further assessments. No opioid-related or treatment-related serious AEs were reported. CONCLUSION: Median time to first opioid administration did not differ between the two groups. No differences in secondary outcomes were observed on the basis of volume administered. These initial findings suggest further study of liposome bupivacaine administered via TAP infiltration as part of a multimodal analgesic regimen in laparoscopic robotic prostatectomy may be warranted.