Study Provides New Insights on Optimal Volume of Local Anesthetic Needed in Erector Spinae Plane Blocks

Newswise — People who undergo surgery to the lower back often have a painful recovery. Erector spinae plane (ESP) block is a recent treatment that involves injecting local anesthetic beneath the muscles that support the spine. The ESP block numbs the nerves of the lower back, reducing pain when the patient wakes up from surgery. Because ESP block is a new intervention, the optimal volume of local anesthetic needed to spread effectively to the relevant nerves is not known. In addition, how ESP block compares to a direct injection of local anesthetic into the erector spinae muscle needs to be explored. A recent study performed ESP blocks on two cadavers to shed light on these questions.

Jeff Gadsden, Jeffrey Gonzales, An Chen, Roy S. Winston, and Jonathan Slonin of Duke University Medical Center, Durham, NC, received a Best of Meeting Abstract Award from the American Society of Regional Anesthesia and Pain Medicine (ASRA) for its 46th Annual Regional Anesthesiology and Acute Pain Medicine Meeting, being held May 13-15, 2021. The authors will present Abstract #2076, “Relationship Between Injectate Volume and Disposition in Lumbar Erector Spinae Plane Block: A Cadaveric Study” on Friday, May 14.

Gadsden et al. injected 10 ml of blue dye mixed with radiologic contrast dye and observed how far the solution spread toward the head and feet using x-rays. Next, they injected another 10 ml, followed by a third injection of 10 ml. On the other side of the body, a surgeon injected colored dye to mimic what would occur during spine surgery. The cadavers were then dissected to observe the spread of colored dye.

The findings showed a positive relationship between volume and spread: 10 ml of dye spread to two spinal levels, 20 ml to three spinal levels, and 30 ml to 4 spinal levels. There was no spread to the epidural space or nerve roots that provide sensation to the legs or belly. The dye from the surgical injection was mostly limited to one spinal level. “These results may help doctors make decisions about how much local anesthetic is needed for various spine procedures,” Gadsden et al. said.