Featured Case of the Month - "Robert Redford"
Signalment:
Robert is an 18 year old thoroughbred gelding
History:
After eating breakfast normally Robert was turned out in pasture with one other horse. A border at the farm saw the other horse kick Robert. When Robert was brought in from turn out it was noticed that he had a laceration in his mouth and Southwest Equine Hospital was called.
Physical Exam:
All vitals were within normal limits. On oral exam there was a laceration on the inside of his lower jaw that extended from between his right 2nd and 3rd incisors to the front of his right canine. The lower incisors were mal-aligned with the right 3rd and 4th incisors pointing downward. On palpation the left and right sides of the mandible moved independent of each other indicating the jaw was broken. The fracture was easily reduced.
The remainder of Robert's head was symmetric, and palpated normally. There was normal airflow from both nostrils. Cranial nerves were intact.
Radiographs: Radiographs were taken by placing the film in Robert's mouth and shooting the x-rays from the bottom of his jaw up to the plate.
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A fracture line extends from the lateral periodontal space of the first incisor, through the tooth roots of the second and third incisors laterally. The fracture line was traced in this image with a darker line to make it more apparent on this reproduced image. Diagnoses: Open simple avulsion fracture of rostral right mandible, that includes tooth root fractures of 402 and 403. |
Treatment:
| Lower image is from Auer and Stick "Equine Surgery"  |
Robert was sedated with Sedivet and his mouth was copiously rinsed. A local nerve block was performed at his mental foramen with 12 cc lidocaine on each side to numb his lower jaw from the canine teeth forward. Intra-oral wiring was used to secure the fractured side of his mandible to the intact contralateral side. This was done by inserting a 14 gauge needle between the teeth at the gum line, and passing 20 gauge stainless steel wires through the needle cannula. The needle guide is removed and the wires are looped around two or more teeth. Multiple overlapping cerclage wires were placed in this manner. Each wire fastens the unstable teeth and associated bone to the normal teeth. The wires are tightened to stabilize the fracture and align the teeth. |
| The two effected right incisors were taken out of occlusion by grinding down the apposing teeth. This prevented contact with the opposing tooth arcade during chewing, this eliminated stress on the fracture site and allowed better healing. |
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Aftercare:
Robert was prescribed oral antibiotics of Sulfamethaxazole and one gram of Bute twice a day for one week. He was also offered a soaked hay pellet diet for a week. Dental wax was used to cover the wires and protect his lips. The wires are removed in 6-8 weeks.
Additional Information:
- Mandibular (lower jaw) and incisor teeth fractures occur from kicks, collisions or from sudden jerking of the head while chewing on stationary objects.
- Fractures of the jaw heal better than fractures of a limb because the only stress on the jaw is from chewing and the mouth has great blood supply.
- Most fractures of the lower jaw are classified as "open" fractures. An open fracture is when the fracture is exposed to the outside environment. The oral cavity has a plethora of bacteria that could potentially infect the bone. But the great blood supply in the mouth gives the immune system easy access to the infection. Thus horses with jaw fractures do very well with just systemic antibiotics.
- After the fracture is stabilized, the horses rarely demonstrate any pain and usually return to eating right away.
- Incisors are used for the prehension of food and to clip off grass while grazing. Horses do not use their incisors to chew their food. Thus, a gruel and mash diet can be offered for a few days after repair but is not necessary.
