Repairing damage to the spine so that a paralysed person regains function is right at the frontier of modern medicine. It is so difficult that, for a long time, it was thought impossible to repair or regrow nerves.
The story of Darek Fidyka, who can walk again after his spine was severed four years ago, is therefore hopeful. But we need to be careful in extrapolating too far from one case.
Fidyka’s spine was damaged in a stabbing and the injury left him paralysed below the chest.
No-one has ever regained the use of their legs after such an injury, but Darek has defied those odds and can now walk with a frame and move his hips and position his body as he wants.
It may not sound like much but, for Darek, it was “like being reborn” according to Geoffrey Raisman, a neuroscientist at University College London who, 30 years ago, came up with the seed ideas that led to Darek’s surgery in Poland.
In Darek's treatment two years ago by Polish neurosurgeons, doctors took olfactory ensheathing cells (OECs) from his nose, which normally help to renew the nerves responsible for the sense of smell and are the only part of the human nervous system that can re-grow after damage.
These were transplanted to the two sides of the break in Darek’s spine and, because it was a clean break, it was possible to graft four strips of nerve tissue taken from ankle across the 8mm gap.
The researchers believe that the OECs encouraged the spinal nerves to grow and re-connect, using the ankle tissue as a bridge. The work is described in the journal Cell Transplantation.
The research project was was funded by David Nicholls, who set up a charity NSIF after his son Daniel broke his neck while on holiday, leaving him paralysed.
Nicholls told ITV News that many people told him he’d be wasting his money by investing it in this research, but that today’s results were the “start of a journey” he hoped would lead to replication in several other patients and, eventually, clinical trials.
Simone di Giovanni, a professor of restorative neuroscience at Imperial College London, agreed that the research would need replication before he was convinced that Darek’s was a significant enough result from which scientists could draw useful conclusions.
“My very initial response was of caution because one patient cannot represent the overall population of spinal cord patients - one case study is always very limited,” he said.
“There are no appropriate controls for this study. So while it may raise hopes, I think it might also raise false hopes for patients, so we have to be very careful.”
One problem is that, following a spinal cord injury, each patient has a different lesion in their spinal cord.
Some lesions may recover to a certain extent, some may not - the variability within the patients can be large. In addition, the OECs themselves can show a wide variety of activity, which only muddies the results further.
In the decades of research using these cells to enact nerve repair - in rats, dogs and non-human primates - the results have been mixed. Some studies show benefits, in others it is not so clear.
Darek's particular case is impressive, but his treatment is just a proof of concept. There's a long way to go before we know if the same technique would be suitable for the wider public.
Despite his caution, di Giovanni is optimistic that patients of spinal injury do have much to look forward to in the coming decades.
In the last 15 years or so there has been tremendous progress in our understanding of the reasons for regenerative failure and our capacity to improve it. So much that, in the last few years, we have been able to enhance the regrowth of nerves in spinal cord injury and, in rodents to a limited extent, promote functional recovery. I’m positive, as much as a scientist can be positive, that we will find a cure for paralysis down the line.