Novel Nerve Block Yields Benefits in Bariatric Surgery

Autonomic neural blockade may represent a unique way to manage postoperative visceral pain and associated symptoms following minimally invasive weight loss surgery, according to a new report in JAMA Surgery.

The novel technique targets blockade of sympathetic and parasympathetic pathways by injecting local anesthetic into the areolar tissue surrounding selected autonomic plexuses. Although the researchers have primarily used the technique during laparoscopic sleeve gastrectomy, they said it could potentially expand to other minimally invasive procedures in the future.

The researchers, led by Jorge Daes, MD, of the Division of Minimally Invasive and Bariatric Surgery at Clínicas Portoazul e Iberoamérica, in Barranquilla, Colombia, have published several recent papers on findings from a pair of clinical trials involving more than 200 patients.

In the first trial, published in 2022, the group found patients undergoing sleeve gastrectomy experienced no complications from the injection and had better control of postoperative visceral symptoms.

A second study, published in September, found patients who received the block at the beginning of the case required less intraoperative narcotics and anesthesia than those who got it at the end of the case, said Eric Pauli, MD, the David L. Nahrwold Professor of Surgery at Penn State Health Milton S. Hershey Medical Center in Hershey, Pennsylvania, and a co-author on the initial paper.

“I believe we demonstrated that these blocks are doing something. There seems to be an effect on intraoperative pain control,” Pauli said.

Postoperative outcomes have improved with the advent of minimally invasive techniques, enhanced recovery protocols, and regional pain management, Daes’ group said. But these approaches do not always address visceral pain and gastrointestinal symptoms, which can compromise patient recovery, particularly after laparoscopic sleeve gastrectomy.

Autonomic neural blockade may offer advantages by controlling visceral pain and reducing such gastrointestinal symptoms as postoperative nausea and vomiting (PONV). What’s more, the technique offers such other potential intraoperative benefits as hemodynamic stability and reduced anesthetic and opioid requirements, thereby minimizing the risk for opioid-related complications, they reported.

In the initial trial, the researchers assessed the effectiveness of laparoscopic paragastric autonomic neural blockade on pain and associated symptoms in a randomized, double-blind clinical trial of 145 patients undergoing laparoscopic sleeve gastrectomy. Participants all received transversus abdominis plane block, with or without the novel technique.

Autonomic neural blockade was associated with a significant reduction in pain, PONV, sialorrhea, and analgesic requirements in the first 24 hours after the procedure. Notably, the total number of opioid doses was more than three times greater in controls at 1 hour (14 doses vs 5 doses) and 8 hours (34 doses vs 10 doses). These differences were largely gone by 24 hours.

In the second study, the researchers examined how the timing of the nerve block affected its performance. In this case, all participants received the block, either at the beginning or at the end of laparoscopic sleeve gastrectomy.

Patients who received the anesthetic block at the onset of surgery consumed significantly less intraoperative remifentanil and sevoflurane than those who received the block at the end of the procedure. Both groups demonstrated comparable patterns of recovery after surgery. A post hoc analysis of these results revealed the block reduced analgesic consumption and effectively alleviated pain and PONV regardless of the timing of administration.

In a third study, Daes and his colleagues compared autonomic neural blockade in laparoscopic sleeve gastrectomy patients using either bupivacaine plus dexamethasone or liposomal bupivacaine. Here they found that while both combinations were effective at reducing pain and PONV 24 hours after surgery, liposomal bupivacaine seemed to be more effective in managing nausea and vomiting.

Complications observed during the series were minor, most noticeably self-limited bleeding at the injection site. Intravascular injection is also a possibility, one that demands careful application of the local anesthetic.

Pauli said expansion of the technique to other surgical procedures is possible. “Dr. Daes now uses the block routinely on gallbladder patients and hiatal hernia patients,” he said. “One of the things that he proposes is that the block can be performed in any surgery involving any organ.”

“For the cost of some local anesthesia and IV tubing, you greatly enhance the patient experience by eliminating a lot of the symptoms that accompany surgery,” Pauli added. “And if you could take even a handful of patients who might stay overnight because of their nausea and vomiting symptoms and turn them into an outpatient stay, you’ve freed up a hospital bed and reduced the workload on nursing and OR staff.”

Hilary P. Grocott, MD, an expert in regional anesthesia at the University of British Columbia in Vancouver, British Columbia, Canada, said autonomic neural blockade has potential to improve clinical care. However, he said the method requires more study to determine its efficacy for more than just the immediate postoperative period.

“The technique is certainly a novel approach to an age-old problem,” Grocott told Medscape Medical News. “Though it shows great promise, its true value is somewhat uncertain due to the relatively short-lived duration of the block’s effect.”

Pauli reported receiving personal fees from Becton Dickinson, Medtronic, Boston Scientific, Actuated Medical, Cook Biotech, Neptune Medical, Surgimatix, Noah Medical, Allergan, Intuitive Surgical, ERBE, Integra, Steris, and Vicarious, and royalties from UpToDate, Wolters Kluwer, and Springer outside the submitted work. Grocott had no relevant financial disclosures.

Michael Vlessides is a best-selling author, biographer, and medical journalist in Canmore, Alberta, Canada.