Partial removal of the mandible

Caution: To ensure the success of this dissection all cuts must be made as close to the bone as possible.

1. Insert the knife rostral to the first cheek tooth (in the diastema) so the blade aligns between the mandible and the buccinator and masseter muscles (lateral aspect of the mandible). Separate the muscle and other soft tissues from the bone advancing caudally and preserving the facial vein/artery and parotid duct. This cut goes through the gums into the oral vestibule, ending behind the last molar.
2. Insert the knife medial to the mandible and separate the soft tissues (base of tongue) from the bone. This cut enters the oral cavity and can be extended through the medial pterygoid muscle to the caudal border of the mandible.
3. Cut the occipital part of the digastricus muscle along its mandibular insertion (horse only in ruminate caudal belly of digastricus).
4. Return to the rostral extent of the incisions made in steps 1 and 2 and insert a needle holder along the medial aspect of the mandible. Insert a finger between the buccinator muscle and the lateral wall of the mandible to feel for the tip of the needle holder. (A dorso-ventral cut through the buccinator muscle may yield visual access to the tip of the needle holder if needed.) Guide one end of an 18? to 24? length of O.B- wire (Gigli wire) along the lateral wall to the tip of the needle holder, grab it with the needle holder and pull it down along the medial aspect of the mandible. At this point the wire should surround the mandible on all but its ventral aspect. Attach handles to the ends of the wire and saw straight down through the mandible.
5. About 4 to 6 cm ventral to the TMJ insert a needle holder horizontally along the medial aspect of the mandible in caudal to rostral direction. A small incision through the soft tissues there is helpful in locating the tip of the needle holder. Grab a length of O.B.-wire with the needle holder and pull it back. Attach handles and saw the mandible straight back. Have colleagues stabilize the horse. Use a wide fore- aft stance and apply moderate force when cutting. As you brake through the bone you could loose balance.
6. Pull or pry the loose part of the mandible outward and cut the muscle fibers that attach to the medial side of the mandible (medial pterygoid muscle). The mandibular artery, vein and nerve will be severed close to the mandibular foramen. Sever any fibers still attached to the loose part of the mandible and remove it without damage to the facial vein/artery and parotid duct.