A new trial published in Nature, described by the journal as an “extraordinary development” has seen a combination of spinal cord stimulation (SCS) and physical therapy help patients walk not just in the lab, but outside in real-world conditions.
Creating a technology that helps people who cannot walk is up there with a cure for cancer: It would drastically better the lives of those who have suffered from a major disability and is one of the holy grails in medical technology. As many as half a million patients have a spinal cord injury, according to WHO.
A growing number of medical technology companies are using SCS to help these patients, but here, researchers treated three men who had severe paralysis—despite repeated attempts at rehabilitation—with a tweaked methodology.
Rather than delivering a constant electric current, as has been tried before, the researchers “applied patterns of stimulation calculated to activate the correct groups of leg muscles at the correct time during stepping,” according to the paper.
This meant that specific locations in the spinal cord could be targeted, to “activate the muscles in a co-ordinated fashion.”
This allowed for an as yet unseen ability to get these men walking again, voluntarily, while keeping this control over previously paralyzed muscles when electrical stimulation was turned off.
Physical therapy was also used to help maintain this, and the paper pointed out that this is not just in controlled laboratory conditions, as these men were able to take walks outside again.
“This indicates that the brain and spinal cord had re-established functional connections, revealing an unexpected degree of plasticity,” an accompanying editorial noted.
Getting down into the technicalities, “Using an implanted pulse generator with real-time triggering capabilities, we delivered trains of spatially selective stimulation to the lumbosacral spinal cord with timing that coincided with the intended movement,” the paper explained.
“Within one week, this spatiotemporal stimulation had re-established adaptive control of paralyzed muscles during overground walking. Locomotor performance improved during rehabilitation.”
But, as ever with treating paralysis, caveats abound, and this is certainly no cure-all. The researchers pointed out that spinal injuries naturally vary massively in their location, severity and outcome, warning, “It will take many more studies to understand who will benefit from this technology.”
The researchers saw this small study as a proof of concept, noting that the patients treated did have a “range of residual leg function at the start of the study.”They concluded that a major challenge is to understand what determines a successful recovery. “For example, one source of variability might be how much sensory information the damaged spinal cord can still transmit to the brain,” they said, calling this test a first step.
A number of recent FierceMedTech Fierce 15 winners are also working on the SCS tech, including G-Therapeutics, which won in 2016 for its work that is a combination of electrical spinal cord stimulation and gravity-assisted physical training, which aims to help spur the innate ability of a patient’s nervous system to reorganize after injury.
And a year later, media-quiet Australian medical device company Saluda Medical, backed by GlaxoSmithKline, won by alsovtargeting a different way: Unlike other SCS systems that make patients correct the stimulation they produce, Saluda’s Evoke tech is set up to measure the body’s response to its output.
Then, accordingly, it automatically adjusts the level as a result of this feedback, as well as its knowledge of the user’s preferences, moving it toward the sort of personalized, precision-based medicine we’ve come to see from the biotech world.
In trials, it works as a temporary system and is placed through an outpatient, and reversible, procedure. It’s connected via a needle to place thin wires in a patient’s back, though the company stresses that no incision is required. The leads connect to a temporary device that fits in a user's pocket.
If a patient wants it long-term, the system can then be implanted via another reversible surgical procedure to place the SCS device and leads beneath the skin.
There’s also been attempts at drugging the problem, although these have had mixed results. There has been some positive, early-stage work using gene and stem cell therapies, but just a few weeks’ back, Vertex cut work on Rho inhibitor VX-210 after a phase 2b acute spinal cord injury trial failed an interim analysis.