Intraoperative neural electrode for continuous monitoring of nerve function

Abstract

Nerve damage is still a major concern in all types of surgery and may result in permanent nerve injury. Real time nerve monitoring can reduce the risk of nerve lesions by continuous surveillance of nerve integrity. A stable proximal stimulation of the nerve and recording at the effector organ is essential and the electrodes should not significantly influence the surgical intervention. This work focuses on the simulation of different electrode designs to compare the results considering the application. Four tripolar electrode designs (cuff, flat, cylindrical and open tube) were simulated by finite-element method. The simulations were performed in 3D and quasi-static electromagnetic case considering the metal-electrolyte interface and the anisotropic conductivity of the nerve. Highest nerve stimulation efficiency was found for the closed cuff design followed by the open tube design. Flat and cylindrical designs were similar. Nevertheless each design has advantages in rela tion to implantation method. The advantages and disadvantages of the electrode designs are discussed

Continuous intraoperative monitoring of autonomic nerves during low anterior rectal resection: an innovative approach for observation of functional nerve integrity in pelvic surgery

“…Increasing edema of the pelvic sidewall was observed during the operation, which might result in varying contact of the tripolar surface electrode to the nervous tissue. The application of a cuff electrode surrounding the nerve would increase signal quality [22] but needs surgical exposure. The dissection of this fine nervous tissue is nearly impossible and would result in unnecessary increased risk of nerve damage during electrode application.…”

Establishment of an in Vitro Model for Stress Testing of Vagal Nerve Cuff Electrodes

“…Additionally, the simulations confirmed that the tripolar electrode had the most selective and highest electrical field and different electrode designs generate different field strength to stimulate the nerve. Earlier research demonstrated with a direct application of the electrode around the nerve the stimulation results will be the best [5]. Although the V3-electrode has lower impedance than the C-electrode and the polyimide electrode, the higher impedance of the C-electrode and the electrode designs of the polyimide electrode are negligible because finally the Celectrode and the polyimide electrode insure through their direct stimulation at the nerve better impedance and so a better stimulation.…”