Health·CBC Explains

'This is not a magic wand': Spinal stimulation used on Humboldt Bronco promising but in early research stages

Spinal cord injury survivors and researchers say patients are anxiously waiting for a cure, but the safety and effectiveness of electrical stimulation therapies still need to be proven.

Clinical trials are underway to study epidural stimulation's safety and effectiveness

Peter Grahn, a neuroscientist at the Mayo Clinic, was paralyzed in a swimming accident in 2005, and now studies epidural stimulation. He understands firsthand how anxious patients with spinal injuries are to see his research become a real-life option, but says it's critical to proceed carefully. (Mayo Clinic)

Recent video from Thailand showing paralyzed Humboldt Broncos hockey player Ryan Straschnitzki moving his legs after an electrical stimulation device was surgically implanted in his spine has sparked excitement — as well as questions — about therapies available to Canadians with spinal injuries.

The procedure Straschnitzki, 20, had is called epidural stimulation, and although promising, it's still highly experimental, experts in both Canada and the U.S. say. It's in early stages of clinical trials in the U.S. and Europe to evaluate the safety and effectiveness of restoring physical abilities — from bowel and bladder function to moving arms and legs — to people who desperately want to get some normalcy back after spinal injury. 

Barry Munro understands all too well why people's immediate reaction is to ask why they can't try the procedure here in Canada.  He's been hoping for — and working toward — finding a cure for spinal cord injury ever since he dove into a lake in his 20s and was left quadriplegic. 

Now 55, Munro is chief development officer for the Canadian Spinal Research Organization and works with the North American Spinal Injury Consortium. For more than 30 years, he's seen the headlines come and go, inciting hope that a cure is on the horizon. 

"I've been down this road before," Munro told CBC News. "I really, really believe in finding a cure and believe it will happen and I have that hope. But — there's a big but — we have to be careful."

Milos Popovich, director of the KITE Research Institute at the University Health Network's Toronto Rehabilitation Institute, echoes that need to proceed with caution. He said that epidural stimulation must proceed through many more stages of scientifically sound clinical trials to prove it works before it could be made available as a therapy in Canada.  

"This is not a magic wand," Popovich said. 

Although both Popovich and Munro want to protect people from false hope, they also say epidural stimulation is a significant area of spinal cord research. It's important, they say, for people to know the facts and understand that it's still early days.  

What is epidural stimulation?

Epidural stimulation involves sending electrical impulses into the spine and was actually developed many years ago as a treatment for people suffering from excruciating pain. Researchers later discovered that in some patients with spinal cord injuries, the electrical impulses stimulating the nerves also appeared to be generating movement. 

Epidural stimulation requires surgery to place electrodes on the surface of the dura, the tissue that wraps around the spinal cord. The surgeons connect those electrodes to a device called an implantable pulse generator (IPG) that is placed elsewhere in the body, often in the patient's lower back.    

Researchers can then start and control the electrical stimulation from a computer that sends wireless signals to the implantable pulse generator, which in turn stimulates the electrodes. 

The idea, in very basic terms, is to stimulate neurons. Researchers say it's important to understand that the movement generated during epidural stimulation lasts only while the device is turned on. Participants in epidural stimulation studies also do many hours of intense physical therapy. 

"It's not just flipping a light switch," said Peter Grahn, a neuroscientist at the Mayo Clinic in Rochester, Minnesota, who has been conducting clinical trials on epidural stimulation. 

In a previous study with two participants, Grahn and his colleagues were able to get them standing without the assistance of a therapist while the epidural stimulation device was turned on.

Grahn himself was paralyzed in by a spinal cord injury in 2005, and is excited about the possibilities epidural stimulation may present. But at the same time, he said, "there's a lot of work that needs to be done on the scientific side" to better understand the specific biology and mechanics at play. 

Is epidural stimulation the only potential therapy?

No. In fact, the next step in Grahn's work is a larger clinical trial that launched earlier this year, comparing epidural stimulation with another potential therapy that also attempts to stimulate the nerves in the spine, but is much less invasive. It's called transcutaneous stimulation (sometimes referred to as surface stimulation) and the device is placed on the skin over the spine, rather than being surgically implanted.

Canada also appears to be much closer to getting a clinical trial in transcutaneous stimulation than epidural stimulation. Popovich said the University Health Network's Toronto Rehabilitation Institute is considering starting a study examining whether transcuteneous stimulation can create upper limb movement. Like epidural stimulation, transcutaneous stimulation is also experimental and in the early stages of clinical trials to assess safety and effectiveness. 

Why is it taking so long?

A significant challenge in spinal cord stimulation is the sheer number of neurons controlling so many different functions of the body, said Milos Popovich of the Toronto Rehabilitation Institute.  

Scientists are still learning how to target the right neurons to get the desired effect (e.g., movement of a leg) — but they also don't want to accidentally create any undesired effects. 

"There's always a drive to try to translate [research] … to the clinic as fast as we can, but there's also the aspect of [doing it] as safely as we can," said Grahn at the Mayo Clinic. "It's a balancing act." 

"The worst thing that could happen right now …  is if somebody were to use the device inappropriately or incorrectly," he said. "And then it sets the whole entire field back because then there's more regulatory scrutiny and everything on these devices because somebody got hurt."

What are the risks?

In the case of epidural stimulation, even the surgery poses a risk.  

'I have that hope. But — there's a big but — we have to be careful,' says Barry Munro, chief development officer for the Canadian Spinal Research Organization, who has been waiting for a cure since a diving accident left him a quadriplegic more than 30 years ago. (Canadian Spinal Research Organization )

Spinal injury not only paralyzes people's legs, arms, or both, but can also leave them with other lifelong serious health issues, such as higher susceptibility to infection or compromised lung capacity that can make surgery more dangerous. 

Electrical stimulation in people with spinal cord injuries also carries potential unintended consequences that researchers conducting clinical trials need to watch out for, said Grahn. 

After injury, the spinal cord no longer communicates when something is wrong and hence the spinal circuitry can "almost go a little bit haywire," he said. 

So if the nerves are being stimulated in the wrong way and something dangerous is happening — such as fluctuations in blood pressure or heart rate — the spinal cord may not send a signal to the brain that something is amiss and needs to be regulated. That makes it especially important for researchers to carefully monitor these vital signs during electrical stimulation, he said. 

Is electrical stimulation just about helping people to walk again?

Walking again is a dream for most people with spinal cord injury, but there are other physical abilities that are even more important to many people that the public often don't think about, said Barry Munro of the Canadian Spinal Research Organization.

Moving arms and hands, bladder and bowel control, as well as sexual function are also areas researchers are looking to improve with the electrical stimulation. 

What does the future look like for spinal injury cures or treatment?

Even though it may be frustrating for people to hear that these therapies are still in the experimental phase, it's important to remember that spinal injury research has made important strides over the past decades, Munro said.

"Has it moved quick enough? I don't think so," Munro said. 

"[But] we're talking clinical trials. I remember the day where that was science fiction. So we have moved the bar."

What's most important now, Munro said, is for researchers across North America — and the world — to communicate with each other, as well as with people actually living with spinal cord injuries. 

As part of that process, it's vital for people with spinal cord injuries to have access to reputable clinical trials they can learn about and possibly participate in, Munro said. His organization recommends a new website launched recently called SCITrials.org, which provides links to clinical trials specifically devoted to spinal cord therapies. 

Clinical trials are moving forward not only in epidural stimulation and transcutaneous stimulation, but also in stem cell therapies and neuroplasticity, which uses activity-based rehabilitation to try to train the neurons and muscles to work around the spinal damage. 

"I'm excited about this," Munro said. "The future is going to be a combination of therapies for a cure."

About the Author

Nicole Ireland is a CBC News journalist with a special interest in health and social justice stories. Based in Toronto, she has lived and worked in Thunder Bay, Ont.; Iqaluit, Nunavut; and Beirut, Lebanon.

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