Introduction
Liposome bupivacaine (LB) is a long-acting anesthetic intended to reduce postoperative analgesia. Studies evaluating the efficacy of the LB against an active comparator (bupivacaine, or placebo) on acute postoperative pain control in hemorrhoidectomy procedures are few and heterogeneous. Therefore, we sought to perform a meta-analysis comparing the analgesic efficacy, and side effects of LB compared to conventional/placebo anesthetic in hemorrhoidectomy patients.

Methods:
This is a systematic review and meta-analysis of articles published from the time of inception of the datasets to August 30, 2022. The electronic databases included English publications in Ovid MEDLINE In-Process & Other Non-Indexed Citations, Ovid MEDLINE, Ovid EMBASE, and Scopus.

Results:
A total of 370 patients who underwent a hemorrhoidectomy procedure enrolled in 4 comparative studies were included. The overall mean age was 39.6 years, (standard deviation [SD] ± 13), and there was a male predominance (63.5% male). 193 (52.2 %) received LB and 177 (47.8 %) received either bupivacaine or placebo. There was no statistically significant difference between LB and the comparison groups in sex, age, or ASA score. Cumulative pain score at 72 hours,
reported by numeric rate scale (NRS) in three studies, showed no difference between LB group vs other conventional/placebo anesthetic (MD -2.4, 95% CI -9.4 – 4.7). However, the dose of rescue medication was significantly lower in the LB group (MD -0.3, 95% CI -0.6 – 0.0). Additionally, the time to the first opioid, reported by two studies, was significantly longer by 525 minutes in LB (median 800min IQR 8-5760) versus conventional anesthetic/placebo (median 275 min IQR 18-5760). Meta-analysis revealed no difference in LB compared to conventional anesthetic/placebo in nausea or vomiting (OR 2.45, 95% CI 0.48- 12.49), anal bleeding (OR
1.54, 95% CI 0.05- 52.25), and gastrointestinal adverse effect (OR 1.47, 95% CI 0.25- 8.60).

Conclusion:
In comparing LB to conventional anesthetic/placebo anesthetic for hemorrhoidectomy, we found no statistically significant reduction in pain score through 72 hours, or in adverse effects. However, LB decreased the time to first opioid and was associated with lower dose of rescue medication compared to conventional anesthetic/placebo.