Iatrogenic nerve damage is one of the most adverse sequalae of tumor resection surgery in all parts of the body. Many neuromonitoring techniques have been developed to lower the incidence of damage, most notably electrostimulation. However, the clinical potential of precise neuromonitoring remains unfulfilled, due to several key limitations intrinsic to electrostimulators. In this work, we will develop a neurostimulator based on the demonstrated ability of infrared radiation to provide fine spatial resolution and scanning ability, while minimizing nerve damage during surgery. We will build and test a small, handheld neurostimulator with optimized parameters and fine control for clinical use in facial surgery. Electrical current can spread through all somatic tissue, and in present neuromonitors this obscures the location and continuity of nerves in the tissue and prevents stimulation of individual nerve fascicles. These stimulators also require contact with the nerve, which can lead to damage, and repetitive contacting of tissue to search a region. In facial surgery, the incidence of damage to nerves is as high as 72%, with an incidence of up to 5.6% for permanent partial or total paralysis. Facial nerve damage can have devastating effects and therefore the current patient outcome is unacceptable. Recently, neurostimulation using pulsed infrared radiation has been demonstrated to overcome these difficulties. Wells and coworkers have shown that the rat sciatic nerve can be safely stimulated with a pulsed near- infrared laser. Tests at Vanderbilt and Northwestern Universities of the Aculight Capella R- 1850 research infrared nerve stimulator have demonstrated very precise spatial selectivity, around 0.2 mm. This work will adapt the research infrared nerve stimulator into a smaller, handheld version for use in facial surgery. To determine the optimal performance parameters, such as power, beam collimation, selectivity, size, cost, we will compare two infrared neural stimulators, the Aculight Capella R- 1850 and the new handheld system to an electrical neural stimulator. We will determine safety and efficacy, demonstrate that these lasers can be used to localize the nerve through tissue layers, and determine which configuration is optimal for ENT surgical procedures. We envision Phase II efforts will develop a clinical infrared nerve stimulator prototype for future clinical trials.
Our objective is to reduce nerve damage during facial surgery by improving intraoperative identification and monitoring of facial nerves. This work will focus on developing an infrared laser nerve stimulator to overcome several key limitations of electrical nerve stimulators. ? ? ?
