Spinal cord stimulator device shows promise in Minneapolis study

Learning to walk again would be great, but for many people with paralysis, shorter bathroom sessions would be a banner achievement.

An ongoing clinical study at Minneapolis hospitals called E-Stand is reporting early success using an implantable medical device designed in Minnesota called a spinal cord stimulator to restore volitional movement and autonomic functions in patients paralyzed from the mid-back down.

"Volitional movements" means being able to move your legs on purpose, while "autonomic functions" refers to functions governed by autonomic nervous system largely without conscious thought, such as regulating blood pressure, urination, and sexual arousal.

Although restoring a person's ability to walk may make for great TV, restoring autonomic functions tops the priorities list for many people with paralysis, E-Stand investigators say.

"In people who have mid-thoracic injuries, the thing that comes up near the top of the list every time is actually bowel and bladder," said Dr. Ann Parr, a lead investigator with E-Stand and assistant professor of neurosurgery at the University of Minnesota.

E-Stand aims to enroll about 100 people with paralysis who are willing to have a spinal cord stimulator made by Abbott Laboratories implanted experimentally in their backs. (More information is available here.)

The magnitude of autonomic changes and movement abilities early on prompted the team to publish an initial report on their first two patients.

Two middle-aged women who were paralyzed from spinal injuries at least five years ago can move their legs again after having the Abbott device implanted to deliver epidural spinal cord stimulation, the study report says.

One of the patients, a 48-year-old who was paralyzed in a motorcycle crash five years ago, found that she could voluntarily move her legs the first time the device was switched on. She reported cutting her "bowel regimen" time from 90 minutes to less than 30 minutes, while clinical testing documented improved blood-pressure stability.

Numerous questions remain, but the findings should lead to an effort to develop strategies "to maximize recovery in all participants with chronic SCI," or spinal-cord injury, the report says.

The study is using Abbott Laboratories' Proclaim Elite neurostimulator, a pain treatment brought to market by St. Jude Medical, the Little Canada-based device maker that Abbott acquired in 2017. Abbott is donating the devices to the study. The research is sponsored by the Minnesota Office of Higher Education's Spinal Cord Injury and Traumatic Brain Injury Research Grant Program. Implants are being done at HCMC and the Minneapolis VA Health Care System using surgeons affiliated with the U.

A news release on the study notes that upward of 290,000 people in the U.S. are estimated to be living with spinal cord injuries, though the idea of using spinal cord stimulation therapy to treat them is still in early phases.

Researchers have been studying the effects of applying current to nerves since the 1960s, not long after the same basic technology was used in implantable pacemakers. Typically spinal cord stimulation devices include a small implantable "pulse generator" that looks like a pacemaker and a sophisticated wire called a lead that delivers energy to a precise target.

Spinal cord stimulators are approved in the U.S. to treat chronic pain, but several different teams are experimenting with the devices to restore movement after paralysis. Researchers at the Mayo Clinic reported last year that one patient in a study was able to take his first steps in years using the device in combination with intense physical therapy.

"We believe that we are studying a population that is much closer to the general population of patients with spinal cord injury," Dr. David Darrow, a U neurosurgery resident and a lead investigator on E-Stand, said in an announcement on the early study results.

The second patient described in the study report was 52 years old and 10 years out from the fall that caused her paralysis. Like the other patient in the study report, she was able to move her legs the first time the spinal cord stimulator was switched on. There was minor improvement in her bowel-voiding score and no evidence that stimulation changed blood-pressure control.

Neither person in the report regained the ability to feel sensations. And neither patient is walking. A new study protocol will be developed for standing exercises once more data are in.

Spinal cord stimulators are not without controversy.

Late last year, a team of journalists analyzed public adverse-event reports on spinal cord stimulators and found that the fast-growing product category accounted for 80,000 medical-device injury reports on file with the U.S. Food and Drug Administration since 2008. Only metal hip implants and insulin pumps had more reports.

In an interview, Hennepin Healthcare neurosurgeon and study investigator Dr. Uzma Samadani said the vast majority of people who get the devices for pain treatment benefit from them. "What we are doing is changing the course of history for people with paralysis, and it's the biggest achievement of my surgical career," Samadani said. "It's amazing."