Abstract
Purpose: :
Cranial nerve seven (CN–7) dysfunction results in an inability to close the eyelid, ocular irritation, corneal breakdown, visual disability and pain. Current therapy results in visual blurring and incomplete relief of symptoms. Utilizing MEMS technology originally developed for the design of computer chips, creation of a biocompatible implantable stimulation chip is possible. The purpose of this experiment was to test the ability of an initial chip prototype to produce a functional blink in denervated orbicularis oculi in rabbits.
Methods: :
Prototype stimulator chips based on MEMS technology were fabricated utilizing photolithography techniques. These prototypes were implanted into the eyelids of two rabbits immediately following surgical denervation of their orbicularis oculi. The rabbits were rested for fourteen days to allow for healing, and completion of wallerian degeneration of their transected facial nerves. Stimulation trials were conducted utilizing the implant. Electromyography (EMG) and videography were used to characterize the response of the orbicularis oculi.
Results: :
Stimulation of two denervated rabbits by prototype implants resulted in successful production of a blink as defined by complete closure of the eyelids. Rabbits were noted to twitch uncomfortably during stimulation initially, but appeared to acclimate, and after a short period showed no signs of discomfort with stimulated blinking.
Conclusions: :
Successful production of a blink in the denervated orbicularis oculi of rabbits suggests that this technology warrants further study for possible utility in reanimating the orbicularis oculi in patients with CN–7 nerve damage.