Ex vivo ovine model for head and neck surgical simulation

To evaluate a fresh, ovine/sheep head and neck tissue model to teach otolaryngology-head and neck surgical techniques.

Observational animal study.

A university animal resource facility.

Tissue was collected from pre-pubescent sheep (n=10; mean age: 4months; mean mass: 28kg) following humane euthanasia at the end of an in vivo protocol. No live animals were used in this study. The head and neck of the sheep were disarticulated and stored at 5°C for 1-5days. The tissues were tested in a variety of simulated procedures by a medical student and four fellowship-trained otolaryngology faculty. Practicality and similarity to human surgeries were assessed.

While ovine head and neck structures are proportionally different, the consistencies of skin, subcutaneous tissues and bone are remarkably similar to that seen in human dissection. Particularly useful were the eyelids and orbits, facial nerve and parotid gland, mandible, anterior neck and submandibular triangle. Surgeries performed included blepharoplasty, ptosis repair, orbital floor exploration, facial nerve dissection and repair, mandibular plating, tracheotomy, laryngofissure, tracheal resection and laryngectomy. The model was also useful for flexible and microsuspension laryngoscopy.

Fresh, ovine tissue provides a readily available, anatomically compatible, affordable, model for training in otolaryngology-head and neck surgery. The use of sheep tissues carries a low risk for disease transmission and is ethically defensible. Structural variations in the sheep temporal bone, paranasal sinuses and skull base anatomy limit the usefulness of the model for surgical training in these areas.