Continuous Interscalene Block Superior To Single-Shot Block With Periarticular Local Infiltration

AUTHOR: Chase Doyle

Anesthesiology News

A study of patients undergoing shoulder arthroplasty has found that continuous interscalene blocks are more effective than single-shot interscalene blocks with periarticular local infiltration for postoperative analgesia.

According to this retrospective chart review, continuous interscalene blocks were associated with a statistically significant decrease in opioid requirements on the day of surgery and the first day after surgery compared with single-shot interscalene blocks with periarticular injection of an analgesic cocktail. The cocktail consisted of a local anesthetic, a vasoconstrictor, an opioid and a nonsteroidal anti-inflammatory drug. Based on the results, continuous interscalene blocks have the potential to eliminate opioid requirements in the immediate postoperative period, the study authors noted.

“For too long, opioids have been treated as a problem-free solution to pain,” said Elird Bojaxhi, MD, an anesthesiologist at Mayo Clinic, in Jacksonville, Fla., and a study researcher. “It’s the responsibility of providers to demonstrate better alternatives and to educate our patients. We hope that the result of the study will encourage the use of continuous nerve block as an alternative to reduce the need for opioids after a surgery.”

“Continuous nerve catheters are more labor-intensive and require a dedicated acute pain service for proper patient follow-up,” Dr. Bojaxhi said. “Periarticular injection of a concoction of medications around the joint, on the other hand, provides analgesia without the need for continuous infusion or patient follow-up.”

He added, “Periarticular injection may help initially to control pain, but it wears off and doesn’t have the same efficacy of a continuous nerve catheter.”

To examine the effectiveness of the two approaches, Dr. Bojaxhi and his colleagues conducted a retrospective review of all patients who underwent shoulder arthroplasty by a single surgeon, in a single institution, between January 2014 and October 2016. The researchers divided shoulder arthroplasty patients into two groups based on postoperative analgesic modality: patients who received a continuous interscalene block using an indwelling catheter (n=63) and those who received a single-shot interscalene block followed by periarticular injection (n=53). Next, the researchers reviewed the chart for each patient to identify average and maximum pain scores on postoperative day (POD) 0 and POD1, opioids given intraoperatively, and opioid consumption on POD0 and POD1.

Significant Reduction in Opioids

As Dr. Bojaxhi reported at the 2018 annual congress of the European Society of Anaesthesiology, continuous interscalene blocks were associated with a statistically significant decrease in opioid requirements on POD0 (11.85 oral morphine milligram equivalents [MME] vs. 40.75 MME; P<0.01) and POD1 (24 vs. 50.34 MME; P<0.01) compared with single-shot interscalene blocks with periarticular injection. The use of a continuous interscalene block was also associated with a significant increase in patients who were opioid-free on POD0 (44% vs. 2%) and POD1 (35% vs. none) compared with periarticular injection (Figure).

“We found that after the initial injection wore off on the day of surgery, patients had a significant amount of pain and required almost three to four times the amount of opioids,” said Dr. Bojaxhi. “On the other hand, almost half of patients who had the continuous infusion did not require any opioids to control their pain on the day of surgery, and on postoperative day 1, 35% of these patients were still opioid-free.”

Although an opioid-sparing effect has been demonstrated, said Dr. Bojaxhi, changing clinical practice will require more than statistical analysis. In addition, providers must challenge the dogma that opioids are the gold standard for pain management. According to Dr. Bojaxhi, overprescribing of opioids has been exacerbated by certain initiatives—such as “pain is the fifth vital sign”—and many surgical practices feel pressured by patient satisfaction surveys, like the Hospital Consumer Assessment of Healthcare Providers and Systems survey, or that from Press Ganey.

“I hope that this study brings to light how it’s not just patients that are ‘hooked on opioids’ as the primary means of pain control, but also many surgical practices,” said Dr. Bojaxhi. “Despite a lot of evidence suggesting otherwise, many surgeons still feel that opioids are the best, most reliable and safest way for treating pain. It’s going to take a multidisciplinary approach from surgical and anesthesia practices to actively seek out solutions that address this issue.”