Spinal cord stimulation reduces pain, improves balance in people with lower limb amputation

Spinal cord stimulation can elicit sensation in the missing foot and alleviate phantom limb pain in people with lower limb amputations, University of Pittsburgh School of Medicine rehabilitation scientists report today.

Pressure sensors on the insole of a prosthetic foot triggered electrical pulses that were then delivered to a participants’ spinal cord. Researchers found that this sensory feedback also improved balance and gait stability. The proof-of-concept study was done in collaboration with Carnegie Mellon University and University of Chicago researchers and reported in Nature Biomedical Engineering.

Unlike the typical stimulation system that works by shutting down pain neurons by overriding them with another sensory signal — similar to how rubbing your sore elbow helps relieve the pain — Fisher’s group leveraged the existing spinal cord stimulation technology to restore sensory feedback by replacing the severed connections between sensory neurons in the missing foot and the central nervous system.

In addition to clinically meaningful improvement in balance control and gait even in the most challenging conditions, such as standing on a moving platform with eyes closed, participants reported an average 70% reduction in phantom limb pain — a highly meaningful outcome given the lack of clinically available treatment options.

The beauty of this technology lies in its versatility: the pilot study showed that it can work in people with extensive peripheral nerve damage due to chronic conditions, such as diabetes, or in people with traumatic amputations. It also doesn’t require costly custom-made electrodes or uncommon surgical procedures, making it easier to scale up on a national level.

Reference: Spinal cord stimulation reduces pain, improves balance in people with lower limb amputation; Nature Biomedical Engineering; DOI: 10.1038/s41551-023-01153-8