1. In patients undergoing open ventral hernia repair with mesh placement, liposomal bupivacaine transversus abdominus plane block did not reduce postoperative opioid use when compared with simple bupivacaine and a placebo.
Evidence Rating Level: 1 (Excellent)
Study Rundown: Multiple pain control strategies that do not rely on opioids have been developed in recent years, especially for post-operative pain. In particular, the transversus abdominus plane (TAP) block can be used to deliver local anesthesia for patients undergoing open abdominal wall reconstruction (AWR), which requires a laparotomy incision. The anesthesia most commonly used is simple bupivacaine, though its relatively short duration of action limits its utility. However, this randomized, double-blinded, placebo-controlled trial sought to compare the efficacy of TAP block with liposomal bupivacaine – which has a longer duration of action due to slow release of the drug from vesicles – with simple bupivacaine and placebo for patients undergoing ventral hernia repair with mesh placement.
Patients were randomized 1:1:1 to receive either (1) 20 mL liposomal bupivacaine + 60 mL bupivacaine hydrochloride 0.25% without epinephrine + 40 mL normal saline (LB); or (2) 60 mL bupivacaine hydrochloride 0.25% without epinephrine + 60 mL normal saline (SB); or (3) 120 mL of normal saline (placebo). The primary outcome was opioid requirement for the first 72 hours after surgery. Following surgery, patients received patient-controlled analgesia (PCA) devices. It was found that in the first 72 hours after surgery, there were no differences between the groups with regards to opioid use as measured by morphine milligram equivalents (MME). Furthermore, there were no differences in daily opioid requirements from postoperative day 0 until discharge.
A particular strength of this study is the inclusion of a placebo group, which in this instance calls into the question the utility of using TAP block for patients undergoing AWR. That LB and SB did not reduce postoperative opioid use compared with placebo is in contrast to previously published reviews, and may speak to limitations of this particular trial, such as the difference in pain related specifically to ventral hernia repair, and its generalizability. Furthermore, the study was not powered to detect differences in opioid use between TAP block with SB and placebo, making it difficult to draw conclusions. In all, though, this randomized-controlled trial demonstrated that LB does not reduce postoperative opioid use when used in a TAP block for patients undergoing open ventral hernia repair.
In-depth [randomized controlled trial]: 164 patients were included in the analysis, 57 receiving LB (median [IQR] age = 59 [52-68] years, 56.1% male), 55 receiving SB (median [IQR] age = 58 [53-69] years, 50.9% male), and 52 receiving placebo (median [IQR] age = 60 [54-65] years, 44.2% male). All patients had a polypropylene mesh placed in the retromuscular position that was fixed with eight transfacial absorbable sutures. The most common complication was ileus, though the incidence in the LB cohort compared with the SB and placebo cohorts was not significant (24.6% vs. 20.0% vs. 11.5%, p = 0.21). As mentioned, there was no significant difference in postoperative opioid requirement in the first 72 hours as measured by MME between the LB cohort and the SB and placebo cohorts (310±272 vs. 325±225 vs. 350±284, overall p = 0.725). Furthermore, there were no differences in pain scores at baseline and at 30-days between the three cohorts, nor were there differences in the quality of life at these two points in time.
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