Posted December 21, 2015
Sameer Shah, Ph.D., University of California, San Diego
Peripheral nerve damage to the extremities of soldiers is often the consequence of an improvised explosive device (IED) impact. This damage results in impaired motor and sensory function and chronic pain, leading to an inability to perform essential daily activities. The degree of recovery is usually poor and current strategies to repair nerve damage are limited, thus development of new methods for nerve regeneration is of high clinical importance. Dr. Sameer Shah, of the University of California, San Diego, has focused his research on developing a new technique for nerve regeneration using the application of tensile loading, or stretching, to accomplish this. Peripheral nerves normally exist under tension, recoil when severed, and stretch during growth and development. As a result, moderate tensile loading is hypothesized to be effective for nerve stabilization following injury and for accelerating regeneration.
With support from an FY09 PRORP Hypothesis Development Award, Dr. Shah and his team have engineered a novel biomedical device to apply tensile loading to the severed nerve, to accelerate peripheral nerve regeneration. This instrument gradually lengthens the intact proximal stump of the injured nerve, which connects to the spinal cord, towards the distal stump, which connects to sensory endings and targeted muscles. When the device was tested in a rat sciatic nerve model, Dr. Shah observed successful rapid lengthening of the injured nerves. This resulted in a "head-start" in the reconnecting of nerve stumps to accelerate recovery of muscle function and proper sensation. Moreover, the nerves adjusted to this tension by increasing production of the biological materials required to sustain their rapid growth.
Dr. Shah is currently expanding testing of this apparatus in a rabbit model with larger nerve defects. With the success he's seen in the rat model, and hopes to recapitulate in the rabbit model, he plans to transition the device into human use in the future. If successful, it could have a significant positive impact on individuals with existing nerve damage, and could also be used in the field to repair peripheral nerve damage experienced by soldiers in battle.
Vaz KM, Brown JM, and Shah SB. 2014. Peripheral nerve lengthening as a regenerative strategy. Neural Regen Res 9(16):1498-1501.
Chuang T-H, Wilson RE, Love JM, et al. 2013. A novel internal fixator device for peripheral nerve regeneration. Tissue Eng Part C Methods 19(6):427-437.