Author: Chase Doyle
A study of three analgesic strategies for major lower extremity amputations reveals that regional anesthesia provides superior perioperative pain control within 72 hours of surgery.
The retrospective review of lower limb amputations showed that peripheral nerve blockade with combined standard and liposomal bupivacaine (Exparel, Pacira) was associated with lower oral morphine equivalents (OMEs) compared with those not receiving regional anesthesia. In fact, patients receiving liposomal bupivacaine with peripheral nerve blockade and standard bupivacaine had 50% lower opioid requirements than those not receiving regional anesthesia.
“This study supports the importance of perioperative anesthetic and analgesic choices for patient outcomes,” said Catalina I. Dumitrascu, MD, a resident physician in the Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, in Rochester, Minn. “The choices we make at the time of surgery may truly impact outcomes beyond the surgical encounter. Given the ongoing opioid crisis, helping to decrease the amount of opioids that our patients are using in the hospital may be a substantial contribution.”
As Dr. Dumitrascu explained, pain control for patients undergoing major lower extremity amputation remains a challenge, as anywhere between 30% and 80% of patients will develop chronic pain. Although many different perioperative analgesic techniques have been studied, said Dr. Dumitrascu, no specific technique has proved to be superior for amputation. In addition, the potential application of liposomal bupivacaine as a regional anesthetic agent for this type of surgery remains incompletely defined. Although only approved for one specific regional technique, interscalene brachial plexus nerve block, liposomal bupivacaine has been used increasingly off-label for other regional blocks, Dr. Dumitrascu explained.
The procedures were divided into three analgesic categories:
The study’s primary outcome was OME at 72 hours. Secondary outcomes included numeric rating scale pain scores and postoperative opioid-related respiratory depression.
At the 2019 annual meeting of the American Society of Regional Anesthesia and Pain Medicine, Dr. Dumitrascu reported data collected from the administration of anesthetics in 631 major lower extremity amputations. Nearly two-thirds (65.9%) of patients included in the analysis received no regional anesthesia (n=416), whereas 13.3% of patients received a regional block with standard bupivacaine (n=84) and 20.8% of patients received a regional block with standard plus liposomal bupivacaine (n=131). Among patients receiving regional anesthesia with a standard local anesthetic, 61% were performed with nerve catheter placement.
As Dr. Dumitrascu reported, multivariable analyses showed that OME requirements were 50% greater in the nonregional group compared with the combined standard and liposomal bupivacaine group (P=0.007; Table). OME use also was higher in the nonregional group compared with the standard bupivacaine group, but these findings were not statistically significant. Of note, a comparison of regional techniques with or without liposomal bupivacaine showed no statistically significant difference in OME requirements.
|Table. Multivariable Analyses of OME Requirements|
|Nonregional vs. Combined Standard/Liposomal Bupivacaine|
|1.50 times greater OME requirements in nonregional group|
|95% CI, 1.12-2.01|
|Nonregional vs. Standard Bupivacaine|
|1.34 times greater OME requirements in nonregional group|
|95% CI, 0.96-1.87|
|Regional With or Without Liposomal Bupivacaine|
|No difference in OME requirements|
|OME, oral morphine equivalent|
According to Dr. Dumitrascu, prospective investigations are warranted to define optimal analgesic strategies in this population, including a focus on long-term outcomes such as chronic pain and phantom limb pain.
“Given the problems associated with chronic post-amputation pain, it will be important to closely evaluate pain, functional status and quality of life for these patients one year out from surgery,” Dr. Dumitrascu said. “Moreover, future investigations are necessary to compare analgesic outcomes of combined standard and liposomal bupivacaine (typically administered as a single-shot injection) versus placement of indwelling peripheral nerve catheters with standard bupivacaine alone, as this could potentially modify practice.”
Single-Shot Liposomal Bupivacaine Could Save Money, and Time
Allan Gottschalk, MD, PhD, an associate professor of anesthesiology and critical care medicine at the Johns Hopkins University School of Medicine, in Baltimore, told Anesthesiology News that the superior acute pain management provided by regional anesthesia is to be expected, but the real question is whether single-shot liposomal bupivacaine can really compete with peripheral nerve catheters of standard bupivacaine.
“The package insert for liposomal bupivacaine says it lasts for 96 hours, and these data suggest that a single shot may be able to provide a level of blockade that’s at least equivalent to nerve blocks continuously infusing 0.5% bupivacaine,” Dr. Gottschalk said. “If liposomal bupivacaine is strong enough to be effective, it could eliminate the need for all the pain services that go with placing and maintaining a catheter, saving a lot of time and money and potentially allowing more patients to benefit.
“We may not always be able to help patients with their pain in the long term, but let’s not discount the importance of having good acute pain management,” Dr. Gottschalk added. “These regional [analgesic] strategies certainly helped these patients acutely.”