A real-world analysis has concluded that using liposomal bupivacaine instead of plain bupivacaine in interscalene blocks can markedly reduce the number of patients who require opioids in the first three days after shoulder surgery.

An added benefit of the switch, the researchers noted, is that surgeons have significantly reduced the number of prescribed opioids after surgery, thereby reducing the number of pills available for possible diversion.

“When we first started looking into this, we were seeing that patients were going home with anywhere from 30 to 84 opioid pills after a shoulder arthroscopy,” said Ryan Mountjoy, MD, an attending anesthesiologist with Spectrum Healthcare Partners in South Portland, Maine. “We realized we needed to do something about it to curb the opioid epidemic that is ravaging Maine.

“When liposomal bupivacaine was approved in 2018 for interscalene blocks, we thought it might be a good way to prolong postoperative analgesia in these patients and cut down on the amount of ‘things’ they’re sent home with. A cost analysis also demonstrated that liposomal bupivacaine would be a significant cost savings over our catheter systems, so there was added incentive to be good stewards of the health care dollar.”

To help determine the effectiveness of the switch, the researchers extracted retrospective data from the electronic medical records of all adult patients who underwent arthroscopic shoulder surgery with an interscalene block containing liposomal bupivacaine at an affiliated surgery center between January and June 2019. Using a separate clinic database maintained by the orthopedic surgeons’ offices, the investigators also tracked outpatient opioid prescription pill counts and postoperative opioid consumption.

“This wasn’t a traditional study, but more of an experiential quality improvement project,” Mountjoy told Anesthesiology News. “So there are definite limitations to some of our data.”

Surgeons Now Prescribe Fewer Opioids

In an approved abstract for the 2020 annual meeting of the American Society of Regional Anesthesia and Pain Medicine (abstract 708), which was canceled due to the pandemic, Mountjoy and his colleagues said that 100 patients were included in the analysis. Surgery was performed by one of three orthopedic surgeons and attended by one of 16 anesthesiologists.

The analysis found that before the introduction of liposomal bupivacaine, approximately 95% of patients undergoing outpatient arthroscopic shoulder surgery reported opioid consumption within the first 72 hours after surgery. This decreased markedly after the introduction of liposomal bupivacaine into the interscalene nerve blocks, as the proportion fell to 47%.

“In these 100 patients, the average block time with liposomal bupivacaine was about 50 hours, compared with approximately 12 hours when we used plain bupivacaine,” Mountjoy explained. “Furthermore, the average VAS [visual analog scale] pain scores over 72 hours were never greater than 3 with the liposomal bupivacaine.”

Indeed, mean pain scores were 1.01 in the PACU, 2.13 at 24 hours after surgery, 2.48 at 48 hours, and 2.81 at 72 hours.

Analysis of postoperative opioid consumption found that before the switch to liposomal bupivacaine, shoulder surgery patients were taking an average of 13.8 oxycodone pills, which represented 35.8% of the total they had been prescribed. Given the success of the program, the three surgeons performing the procedures decreased their prescriptions from between 30 and 84 pills each to 12 and 25 each.

“We have effectively decreased the pill count of postoperative opioid prescriptions by over 50%,” Mountjoy said.

Although Mountjoy acknowledged that clinicians’ experience with liposomal bupivacaine has been varied, he said it’s been a “game changer” in this patient population.

“It’s really about optimizing the technique where it will be successful,” he explained. “When liposomal bupivacaine was first approved, surgeons were using it for everything. But it behaves so differently than plain local anesthetic, and there were some initial frustrations with its effects.

“I think what we are finding is that anesthesiologists’ use of it in peripheral nerve blocks is showing more reliable results as we refine our technique for its injection.”

Although Mountjoy noted that his group’s experience is not a randomized controlled trial, he was nonetheless encouraged that the switch to liposomal bupivacaine seems to be keeping excess narcotics form being prescribed to patients, where they often become the subject of diversion.

For Alan D. Kaye, MD, PhD, the results of the study are predictable based on the extended duration activity of liposomal bupivacaine. “The FDA approved an extended indication for this drug to include brachial plexus blockade in April 2018,” said Kaye, the vice chancellor of academic affairs, chief academic officer, and provost at Louisiana State University School of Medicine in Shreveport.

“The results are consistent with what we are seeing clinically with shoulder surgery patients,” Kaye continued. “Given that so many patients with this type of surgery have had large and long-duration opioid prescriptions contributing to the opioid epidemic, these results are exciting and reinforce the role for ultrasound-guided regional anesthesia to reduce postoperative opioid consumption.”

—Michael Vlessides