A team of engineers, neuroscientists and surgeons from the University of Cambridge developed the devices and used them to record the nerve signals that come and go between the brain and spinal cord. Unlike current approaches, Cambridge devices can record 360 degree information, giving a complete image of spinal cord activity.
Tests in lively animal and human body models showed that the devices could also stimulate the movement of the limbs and avoid the complete lesions of the spinal cord where communication between the brain and the spinal cord had completely interrupted.
Most current approaches to treat spinal lesions involve drilling the spinal cord with electrodes and placing implants in the brain, which are high -risk surgeries. The devices developed by Cambridge could lead to treatments for spinal injuries without the need for brain surgery, which would be much safer for patients.
While these treatments are still at least several years away, researchers say the devices could be useful in the short term to monitor spinal cord activity during surgery. A better understanding of the spinal cord, which is difficult to study, could lead to improved treatments for a variety of conditions, including chronic pain, inflammation and hypertension. The results are reported in the journal Science Advances.
“The spinal cord is like a road, carrying information in the form of nerve impulses to and from the brain,” said Professor George Malliaras of the Department of Engineering, who directed the investigation. “The damage to the spinal cord causes this traffic to be interrupted, resulting in a deep disability, including the irreversible loss of sensory and motor functions.”
The ability to monitor the signals that go and from the spinal cord could dramatically help in the development of treatments for spinal injuries, and could also be useful in the closest term for better spinal cord monitoring during surgery.
“Most technologies to monitor or stimulate spinal cord interact with motor neurons along the back, or dorsal part, part of the spinal cord,” said Dr. Damiano Barone of the Department of Clinical Neurosciences, which co-riddled the investigation. “These approaches can only reach between 20 and 30 percent of the spine, so it is obtaining an incomplete image.”
When inspired by microelectronics, researchers developed a way to obtain information from the entire spine, wrapping very thin and high resolution implants around the circumference of the spinal cord. This is the first time that a safe 360 degree record of the spinal cord has been possible: previous approaches for 360 degree monitoring use electrodes that pierce the spine, which can cause spinal lesions.
Biocompatible devices developed by Cambridge, only a few million meters thick, are performed using advanced photolithography and thin films deposition techniques, and require a minimal power to function.
The devices intercept the signals that travel in the axons, or nerve fibers, of the spinal cord, which allows the signals to be recorded. The thinness of the devices means that they can record the signals without causing any damage to the nerves, since they do not penetrate the spinal cord itself.
“It was a difficult process, because we have not made spinal implants in this way before, and it was not clear that we could place them safely and successfully around the column,” Malliaras said. “But due to recent recent advances in both engineering and neurosurgery, the planets have aligned and we have achieved great progress in this important area.”
The devices were implanted using an adaptation to the surgical routine procedure so that they could slide under the spinal cord without damaging it. In the tests using rat models, the researchers successfully used devices to stimulate the movement of the limbs. The devices showed a very low latency, that is, their reaction time was close to the human reflective movement. Other tests in human corpses showed that devices can be placed successfully in humans.
Researchers say their approach could change the way in which column injuries are treated in the future. Current attempts to treat spinal injuries involve brain and spinal implants, but Cambridge researchers say that brain implants may not be necessary.
“If someone has a spinal injury, their brain is fine, but it is the connection that has been interrupted,” said Barone. “As a surgeon, you want to go where the problem is, so adding brain surgery on spinal surgery only increases the risk for the patient. We can collect all the information we need from the spinal cord in a much less invasive way, so this would be a much safer approach to treat spinal injuries.”
While a treatment for column injuries is still years away, in the closest term, devices could be useful for researchers and surgeons to learn more about this vital part, but little studied, in a human way in a non -invasive way. Cambridge researchers currently plan to use devices to monitor nerve activity in the spinal cord during surgery.
“It has been almost impossible to study the entire spinal cord in a human, because it is very delicate and complex,” Barone said. “Monitoring during surgery will help us better understand the spinal cord without damaging it, which in turn will help us develop better therapies for conditions such as chronic pain, hypertension or inflammation. This approach shows enormous potential to help patients.”
The research was supported by the Royal College of Surgeons, the Academy of Medical Sciences, Health Education, England, the National Institute for Health Research, the confidence of MRC in the concept and the Engineering and Physical Sciences Research Council (EPSRC), part of the United Kingdom research and innovation (UKRI).
Reference:
Ben J Woodington, Jiang Lei et al. “Flexible circumferential bioelectronics to allow 360 degrees of the spinal cord”. Scientific advances (2024). Doi: 10.1126/Sciadv.adl1230
