The technique is called percutaneous peripheral nerve stimulation. It involves inserting a small cable next to a nerve and using a stimulator to administer a slight electric current to the affected area, interrupting the transmission of pain.
A team led by Dr. Brian Ilfeld of the University of California, San Diego, tested the device on patients who were having surgery on their foot, ankle or knee or major shoulder surgery. The cable can be placed while the patient is awake, without the need for sedation.
“It’s pretty simple,” Ilfeld said. “Sleep on your skin and place the needle in this location … then use a ultrasound machine to guide the needle towards the target nerve and about an inch away, unfold the cable that is inside the needle. So all you have to do is remove the needle, which leaves the lead in place. “
Patients have the procedure and wake up with the device ready to begin. They are already comfortable, because doctors use nerve blocks to relieve pain for 10 to 12 hours, Ilfeld said.
“When they’re in the recovery room, we attach a stimulator, which is about the size of two and a half dollars placed next to each other,” he said. “It’s small enough that you can stick it to the patient.”
At home, participants used a battery-powered pulse generator to control electrical stimulation.
Sixty-five volunteers were part of this pilot study, with 31 in the group of active devices and the rest receiving a fictitious device. They all received opioid pain medications just in case. Two weeks later, lead was removed during a postoperative check-up. Patients were followed for up to four months.
The findings, recently published online in the journal Anesthesiology, they were better than doctors might expect.
“We have drastically reduced opioid use by 80% and we have reduced pain scores by 60%,” Ilfeld said. “So it was a lot more powerful than we had anticipated.”
The possibilities are promising, but the size of this initial study was too small to make definitive claims, Ilfeld said. In addition, the device can only function in relatively small areas of the body and would not be effective for a procedure that encompasses multiple nerve regions, he explained.
A larger study is underway to see if the nerve stimulation technique could be integrated into future surgery pain relief practices.
If the method becomes the norm, the implications could be revolutionary, according to Dr. David Dickerson, chairman of the Pain Medicine Committee of the American Society of Anesthesiologists.
“While we have developed all sorts of new anti-inflammatory and nerve blocks, patients after surgeries still have almost the same incidence or likelihood of having moderate to intense uncontrolled pain,” 15 to 20 years ago, Dickerson said. One thing that leads to a more than 50% reduction in pain and an 80% reduction in opioid exposure is, “for the first time, something that will move that needle,” he added.
Dickerson said SPR Therapeutics, creator of the stimulation system, had paid him to show other doctors how to use the device for chronic pain. He added that he has no other financial ties to the company.
The breakthrough could help alleviate the nation’s opioid epidemic.
An estimated 2 million Americans abuse drugs and 90 people a day die from opioid overdoses. Many start using them in the hospital to control the pain and then can’t stop.
Ilfeld said, “One of the ways people become addicted to opioids is to get them first after surgery for postoperative pain control, and then they continue to use them and continue to want them.”
Although some patients in the study needed opioids in addition to nerve stimulation, any technology that reduces medication use could save lives, doctors said.
For more information on postoperative care, visit US National Institutes of Health.
SOURCES: Brian Ilfeld, MD, MS, Professor, Anesthesiology, University of California, San Diego; David Dickerson, MD, chairman of the Pain Medicine Committee of the American Society of Anesthesiologists and head of pain medicine section, NorthShore University Health System, Evanston, Ill .; Anesthesiology, April 15, 2021, online