Traumatic Fracture of Mandibular Symphysis

Case History;

A 3-month-old colt had a piece of rebar trau
matically penetrate his lower mandible just
caudal to his incisors. This trauma caused a
compound fracture of the mandibular sym
physis. The rebar entered from the bottom of
the jaw and penetrated through the mandible
into the oral cavity. An attempt to stabilize the
fracture was made by intraoral wiring of the
incisors, but the results were unsuccessful.


The fracture had not healed, and the incisor
alignment was deviated due to the tension
placed on the intraoral wires. There was a
fistula where the rebar had penetrated the oral
cavity. Radiographs indicated a nonunion
fracture of the mandibular symphysis, with
signs of bone infection.
Our first concern when devising a treatment
plan was the infection in the bone and sur
rounding tissue. We needed to control the
infection and eliminate any further contami
nation to the area. Antibiotics alone, with
out addressing the fistulous tract, would not
work. We surgically debrided the fistula and
cleaned it with antiseptics. The tract could not
be left open because the area would be recon
taminated. There was not enough good tissue
around the tract to use for an oral closure, so
we borrowed a flap of tissue from the cheek
just lateral to the tract. This flap was sutured
to the edges of the freshly debrided fistula so
that it was completely covered. A thin bead
of surgical glue was applied to the suture line
to help seal the tract. To add further support
to the sutured area, the tongue was dried and
glued down over the surgical area. It is impor
tant that this suture line does not dehisce and
allow contamination to reoccur. The mouth
heals very
Case 12
Traumatic Fracture of
Mandibular Symphysis
Figures 82, 83, 84
quickly, and it is only necessary for the sutured
area to hold for 5 to 7 days. Glue used in the
oral cavity, which is a wet environment, is of
questionable benefit, however in this case the
glue did hold the tongue in place over the area
for 4 days. This was obviously long enough
for the suture line to seal, because the tract
healed very well with no signs of infection.
No attempt to stabilize the fracture was done
at this time. The foal was placed on a soft diet
and seemed to get along okay with it. Also,
we prescribed oral antibiotics for 6 weeks post


The foal was reexamined 3 months post sur
gery. The fistula was filled in and had healed
with no signs of infection. The borrowed mu-
cous membrane flap tore loose eventually, only
leaving a slight scar in the cheek area where it
had been incised. The mandibular symphysis
fracture was stable but had healed in a devi
ated alignment. Radiographs indicated healing
of the symphysis, with no signs of infection. It
was now time to address the misalignment of
the mandible. We decided to use relief cuts to
allow the mandible to grow into a more proper
positioning. The colt is now 6 months of age
and will still have considerable growth of the
mandible. The tooth buds of the lower inci
sors possibly have permanent damage and will
not erupt normally, if at all. However, at a 2-
year followup, all of the teeth had erupted and
were in fairly accurate alignment. The over
bite seen at 3 months of age was almost totally
corrected by 2 years of age.

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