Surgical approach to model facial nerve paralysis in an ovine model for in vivo testing of a novel intervention

Facial nerve paralysis (FNP) disrupts neural inputs to the facial muscles, the most significant being those responsible for blinking. This loss often results in discomfort, corneal exposure, and if improperly treated, vision loss. FNP typically presents unilaterally, resulting in an asymmetric face, causing distress and social isolation. The Bionic Lid Implant for Natural Closure (BLINC) was developed to restore functional blinking in patients with FNP by mechanically actuating eyelid movement via an upper eyelid sling, with a focus on restoring a natural and symmetric appearance. To move this novel intervention toward clinical application, a reliable animal model was needed to assess the function and safety of such a device and optimize the surgical implantation of BLINC. The sheep was chosen owing to the anatomical size and shape similarities of the orbit relative to humans, lending to the testing of human-sized implants. Four sheep underwent facial nerve resection and subsequent BLINC implantation in the temporal fossa. Postoperative assessments confirmed uneventful surgical recovery and effective paralysis induction with no additional functional deficits, supporting the use of this ovine model of FNP for the assessment of novel interventions. The study demonstrates the feasibility of surgical implantation of the BLINC device in a large animal model, laying the groundwork for further testing and eventual human application.