Originally published by our sister publication Pain Medicine News

PARIS—Posterior quadratus lumborum block offers better short-term pain relief than erector spinae plane block in patients undergoing laparoscopic abdominal surgery, a new meta-analysis has found.

The findings indicated that patients who underwent the posterior quadratus lumborum block had lower pain scores at 24 hours than their counterparts receiving the erector spinae plane block. But patients in both groups consumed comparable amounts of opioids and experienced similar rates of adverse events in that same period.

“The idea for this meta-analysis came from my growing interest in understanding the impact of regional anesthesia on pain management in minimally invasive surgery,” said Marcela Tatsch Terres, a medical student at the University of South Santa Catarina, in Santa Catarina, Brazil. “Laparoscopic abdominal surgeries are widely performed, yet there is a lack of evidence to assist clinicians in selecting between different blocks.”

To fill this knowledge gap, the investigators chose to compare the two blocks by assessing available data. They searched the MEDLINE, EMBASE and Cochrane databases for randomized controlled trials comparing posterior quadratus lumborum block with erector spinae plane block in laparoscopic abdominal surgeries. Two reviewers independently extracted data on pain scores, opioid consumption and occurrence of adverse events in the first 24 hours after surgery.

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In a presentation to the 2023 World Congress on Regional Anaesthesia & Pain Medicine, the systematic search yielded a total of four randomized controlled trials comprising 271 patients (age range, 18-70 years), 134 of whom had undergone erector spinae plane block. None of the patients had any contraindication to peripheral nerve block, and ASA physical status classification ranged from I to III.

It was found that pain scores at 24 hours were significantly reduced in patients who underwent posterior quadratus lumborum block (P=0.03). However, opioid consumption (P=0.93) and the incidence of postoperative nausea and vomiting (P=0.91) were comparable between patients in both groups.

The findings were unexpected, Tatsch Terres said in an interview with Pain Medicine News.

“It was surprising to see a P value so close to 1 in two of our pooled analyses. Upon initial review of our included trials, some displayed highly significant differences favoring each of the blocks. So, it was interesting to see how these differences ultimately canceled each other out.”

While the meta-analysis may have indicated that posterior quadratus lumborum block is superior to erector spinae plane block in patients undergoing laparoscopic abdominal procedures, the investigators recognized that more comparative research needs to be performed before the question can be answered fully.

“Our study comprised a relatively small number of patients and randomized controlled trials, and only one of our outcomes yielded a significant difference,” Tatsch Terres noted. “While the assessment of pain scores significantly favored the posterior quadratus lumborum block, this was not reflected in postoperative opioid consumption, which is also extremely relevant in assessing pain management.

“In light of these results,” she said, “I believe that the choice between the two blocks should be tailored to the specific needs and preferences of the patient and the surgical team, while more randomized controlled trials are needed to refine our assessments.”

Theresa Bowling, MD, agreed with the notion of using surgery-specific blocks, a strategy she and her colleagues regularly use.

“In general, we use transversus abdominis plane blocks for the majority of our minimally invasive abdominal surgeries except for nephrectomies and adrenalectomies, for which we perform quadratus lumborum blocks.” Bowling is the director of anesthesia at the Connecticut Orthopaedic Institute and St. Vincent’s Medical Center, in Bridgeport, Conn.

Regardless of the type of block or approach used, Bowling explained that regional anesthesia is consistently integrated into her team’s opioid-sparing multimodal analgesia protocols. “This approach aims to provide effective pain relief while minimizing the need for opioids, thus reducing the risk of opioid-related side effects such as nausea and vomiting.”

She and her colleagues also use total intravenous anesthesia for these cases. “By avoiding inhalational agents, we can eliminate another frequent source of nausea and vomiting,” she said. “This proactive measure enhances the overall patient experience and contributes to a smoother and faster recovery process.”

Bowling also found it interesting that the study found similar opioid consumption by patients receiving both blocks, despite differences in pain scores. “It indicates that pain severity alone might not be the sole driver of opioid use,” she said. “Other factors, such as opioid prescribing practices or patient expectations, could be influencing this aspect. Further research could help pinpoint these factors and guide more rational opioid prescribing.”

—Michael Vlessides

Bowling reported a financial relationship with Sonosite. Tatsch Terres reported no relevant financial disclosures.