Development of a Mouse Model for Studying Oronasal Fistula Using Opthalmologic Cautery

Begin by securing an anesthetized female mouse to a foam board covered with sterile sheets. Then, carefully tape the mouse in a supine position to a surgical platform. Position two needles in front of the orbital airplane.

Place two more needles behind it. Next, place a rubber band around the needles and cross the incisors to hold the mouth open. Use microsurgical tweezers to prop open the corners of the mouth.

Proceed to retrieve the heated ophthalmologic cautery. Now position the cautery tip one millimeter from the midline intersection of the palate and first premolar to create a full thickness mucosal injury to the hard palate. Remove the cautery when the mucosa around the tip turns white.

Heat the ophthalmologic cautery to 250 degrees Celsius in the germinator for 10 minutes. Then, place it on the hard palate and enlarge the wound around the edges. Finally, use microsurgical scissors to excise any excess denatured soft tissue surrounding the wound.

Afterward, apply sterile cotton to stop bleeding and prevent inhalation asphyxiation in the mouse. Notable variability was observed in the size of the generated oral nasal fistula. The wound size showed a significant variation on the seventh day post-surgery.

A significant reduction in the body weights of the mice was also observed on day seven, which is approximately 25%Histological analysis of the oral nasal fistula revealed a loss of hard palate mucosa, denuded bone, and oronasal fistula formation.