Repairing spinal cord injuries with electrical stimulation

Spinal cord injuries can be excruciatingly painful and often debilitating. Direct current electrical stimulation was proposed as a possible way to expedite central nervous system recovery. This method involves applying long, continuous pulses of direct current to mimic the natural electrical fields that aid in tissue development. Though initially promising, technical limitations plateaued momentum in the field.

Matter et al. presented the case that with today’s improved materials and engineering tools, biocompatible direct current electrical stimulation deserves further study.

In direct current stimulation, electrodes send electrical impulses through tissue, creating an electric field and altering ion behavior.

“While the mechanisms are yet to be fully elucidated, electrical stimulation provides navigation cues for neural fibers and guides their growth direction like a compass guides people during hikes,” said author Lukas Matter. “This increases the chance that healthy neuronal fibers grow around or through the injured area and form functional connections around the injury.”

The materials used for the electrodes must fit challenging requirements. Certain combinations of stimulation parameters and metals can result in toxic ions. Implants must be flexible enough to contort to the spine’s curvature without being too thick or causing compression. Recent advancements in implant technology and novel materials make this possible.

Electrical stimulation could have a range of applications beyond spinal cord injury. For example, electrical fields could help heal wounds on the skin faster.

“The field of electrical stimulation of the body is exciting,” Matter said. “There is still a lot of work to do to understand the cellular mechanisms which lead to regeneration during electrical field stimulation.”

Source: “Generation of direct current electrical fields as regenerative therapy for spinal cord injury: A Review,” by Lukas Matter, Bruce Harland, Brad Raos, Darren Svirskis, and Maria Asplund, APL Bioengineering (2023). The article can be accessed at https://doi.org/10.1063/5.0152669 .