Unmet Need
Intraoperative nerve action potential (NAP) is the most common and useful tool for surgeons to guide decisions on surgical approaches during nerve repair surgeries. In a recent trial conducted with 1975 nerves, 57% of the neural elements were completely and perfectly repaired using NAP. Many researchers believe the number of successes would be much higher if the current method of implementing NAP were not so technically challenging due to observed large stimulus artifacts. In order to improve outcomes and reduce artifacts within the procedure, there is a need for a better method to acquire clean NAPs intraoperatively.
Technology Overview
Researchers recorded NAPs from surgically exposed peripheral nerves in monkeys. To test their assumptions about observed artifacts, they recorded additional responses in a simple model system. They found that large stimulus artifacts obscured NAPs when the nerve segment was lifted up from the surrounding tissue with standard hook electrodes. Artifacts were suppressed and NAPs emerged when “bridge grounding” was applied. Tests in this model system suggested that large stimulus artifacts and the clarity of NAP through “bridge grounding” are related to a loop effect created by lifting the nerve. Thus, clean NAPs were acquired in “non-lifting” recordings from the monkey peripheral nerves using newly designed electrodes. The researchers also applied their insights to a clinical case in the OR. In a human brachial plexus lesion case, “bridge grounding” efficiently improved intraoperative NAP recordings.
Stage of Development
The “bridge grounding” method has been tested in animal models as well as clinical practice. It is now being applied to more clinical human trials. The nonlifting nerve recording method using the newly designed electrodes has been tested in animal models and is under translation to clinical development.
Publication
Wu, G. et.al. J. Neurosurg. 2019 Aug 16:1-10
Wu, G., Belzberg, A., Nance, J. et al. Artifact reduction by using alternating polarity stimulus pairs in intraoperative peripheral nerve action potential recording. J Clin Monit Comput (2020)
