Experts Respond: Epidural stimulation treatment for paraplegia

The Lancet has published a case study revealing a experimental treatment for spinal damage and dysfunction leading to a loss of motor function. Independent experts, while excited and optimistic, caution that the more research is needed to really assess the treatment.

Rob Summers was paralysed from the chest down after a car accident in 2006, but five years later an experimental new treatment using electrical stimulation of the lower spinal cord has aided previously wheelchair bound Summers in standing upright. More information about the treatment can be found in the original abstract of the case report, news coverage and video footage.

Our colleagues at the Canadian Science Media Centre have collect comments regarding the treatment from experts in spinal neuroscience and rehabilitation.

Feel free to use these comments in your articles. To talk to a New Zealand expert, please contact the New Zealand Science Media Centre (

Vivian K. Mushahwar, Ph.D., Associate Professor and Alberta Heritage Foundation for Health Research Senior Scholar, Dept. of Cell Biology and Centre for Neuroscience, University of Alberta

“I have followed the progress of using epidural stimulation in humans for a very long time and have been interested in seeing how this latest implantation works out.  Epidural stimulation has been used since the early 1960s as a method for alleviating pain and subsequently for reducing spasticity (spasms, uncontrolled movements) associated with neurological conditions such as spinal cord injury.  In the 1980s and 1990s, the Russians noted that epidural stimulation could produce walking-like oscillations in the muscles of the leg when a person lies supine, and Drs. Hiping Ji and Dick Herman (Arizona State University) implanted the first volunteer (with ASIA C spinal cord injury – i.e., some sensory and some motor function were retained after the injury) with an epidural stimulation device after he had received treadmill locomotor training (very similar to the training procedure received by the individual highlighted in this publication).  The volunteer in Arizona reported improvements in his walking ability using this system.

The present publication continues this train of work.  The new aspect relates to combining locomotor training and epidural stimulation in a person with an ASIA B injury (i.e., some sensory function is retained by no motor function).  The restoration of sit-to-stand and standing for a few minutes is impressive but other electrical stimulation systems have already produced such results in the past with perhaps less effort and more graceful movements.

The most exciting finding to me is that epidural stimulation appears to have enhanced this person’s motor abilities (i.e., his ability to move portions of his legs voluntarily).            This suggests that his spinal cord may have retained important connections from the brain, but these on their own were much too weak to produce voluntary movement.  By providing neural excitation, the electrical stimulation may have assisted these connections and enhanced their functional outcome in the spinal cord. This would be very interesting to follow.  In animal models with complete spinal cord injury (i.e., complete transection of the spinal cord) this finding was not observed because no physical connections between the brain and the spinal cord are retained.  In humans with spinal cord injury, the spinal cord is rarely fully transected (even if the injury is clinically classified as complete, i.e., ASIA A).  Some very weak connections may still persist and epidural stimulation would, as in this case, improve their function.

But, as exciting as this is, we should be very careful in how we communicate this to the public.   We should also be very careful about how we define functional benefits to ensure that the hopes and expectations are realistic.  Standing is a very important function that many people with spinal cord injury find extremely helpful in their daily life.  Enhancements in sexual, bladder and bowel functions are also important functions that make a huge difference in the life of a person with spinal cord injury.  Walking, on the other hand, is more challenging and should not be perceived as a feasible outcome in people implanted with epidural stimulators  if their injuries are severe (ASIA A, B).  Other electrical stimulation approaches (available or under investigation) appear to be much more effective in restoring functional, independent walking.

In summary, the work presented in this publication is not novel in that epidural electrical stimulation and treadmill locomotor training have been used in combination in the past.  What’s new is that the study participant in this publication had an ASIA B injury and his electrical stimulation appears to enhance weak retained connections that on their own could not elicit voluntary contractions.  This latter part is the most exciting part and warrants additional testing.  The intervention is not a miracle cure and its effectiveness and the resulting functional gains should be compared to that of other interventions; however, it is a proof-of-principle that can be capitalized on as we proceed with developing interventions for restoring function after spinal cord injury. ”

Michael Fehlings, Professor of Neurosurgery, University of Toronto, Medical Director Krembil Neuroscience Centre, Toronto Western Hospital

“It is a potential breakthrough–provided the results are validated.

“On the positive side, it shows the feasibility of potentially activating locomotive neural networks in people with significant spinal injuries.  It’s a very well done study and is very well documented which brings hope to individuals with spinal injuries.

By and large, they’ve helped activate muscles in an individual with a severe injury, it’s a very  remarkable, exciting finding.

On the flip side, it needs to be recognised that it is essentially a case report. It is only one patient. So it sets the stage for future research – what needs to be done now is a clinical trial to determine

how robust and generalisable the treatment is.

It’s also important to note that this has been previously reported, it’s not the first time this sort of activation has been demonstrated. There have been previous reports published that didn’t garner quite as much excitement, most notable one conducted in Texas by Dimitrovich which was referenced in the Lancet article.

The treatment is more likely to help younger patients with less severe injuries, although it’s remarkable that Robert Summers’ was quite severe. It’s a very exciting finding but it has the caveat:  it’s only one patient alone.”


Dr Tania Lam, Assistant Professor, Canadian Institutes of Health New Investigator, School of Human Kinetics, International Collaboration on Repair Discoveries (ICORD), University of British Columbia

“There have been previous reports (also in only 1 subject) that showed that epidural stimulation combined with treadmill training could facilitate walking outcomes:

– IEEE Trans Neural Syst Rehabil Eng. 2004 Mar;12(1):32-42. Epidural spinal-cord stimulation facilitates recovery of functional walking following incomplete spinal-cord injury. Carhart MR, He J, Herman R, D’Luzansky S, Willis WT.

However, I believe the person was an ASIA C individual, meaning that he would have had some remaining function in the muscles below the level of injury. In the Lancet paper, the person is an ASIA B, meaning that he would have no residual voluntary activation of the muscles below the injury. Typically, we have shied away from rehab therapies focused on the recovery of walking in such individuals as it has not been shown before that they can recover functional ambulation. This is very novel and promising result. Also, they report other benefits besides walking ability, such as changes in bladder / bowel function and tolerance to temperature changes.

About half of SCI patients will have motor-complete injuries, so this potentially could help a significant sub-set of patients. In terms of practicality and applicability, I can’t really comment on this as I think it largely depends on the surgical risks associated with implanting such stimulators, and the long-term viability of the stimulators. However, if you think about technologies such as deep brain stimulation for Parkinson’s disease, it certainly shouldn’t seem out of reach.”