Pulse - March 2022 - 15

ANIMAL SPECIALTY & EMERGENCY CENTER DIMENSIONS IN SURGERY & CRITICAL CARE
tissue from the maxilla was excised. The
right angularis oris axial pattern flap was
harvested and rotated to cover the right
defect. An extra fold of skin was left intact
at the ventral rostral aspect of the flap so
as not to compromise blood supply. All
skin edges were sutured together with
3-0 Ethilon, interrupted pattern. A small
Penrose drain was placed to account for
dead space near the masseter muscle (Figure
1c). The patient was re-positioned in
right lateral recumbency, and the surgery
was repeated on the opposite side. The
patient was able to expand the mouth to
3cm tip to tip of the canine teeth, post
operatively. Recovery from surgery and
anesthesia was uneventful. The following
day, the patient appeared comfortable
and was discharged with gabapentin
(7.5mg/kg PO q8h), Carprofen (2mg/kg
PO q12h), and cefpodoxime (7mg/kg PO
q24h). The surgery site was moderately
edematous and there was a mild amount
of serous exudate from the Penrose drain
at 5 days post op the Penrose drain was
removed routinely, there were no complications
seen at this time.
The patient presented for the 2-week
post op suture removal/ phase 2 of surgery,
with the complaint of purulent exudate
leaking from the dorsal junction of the two
angularis oris flaps. On examination there
was evidence of devitalized tissue on the
dorsal right side of the flap that was tender
to the touch. Bilateral mandibular advancement
flaps and exploration of the angularis
oris flap reconstruction surgery was then
performed. The anesthetic protocol was
repeated as described previously for phase1.
During the surgical preparation period,
skin sutures were removed. The muzzle
was cleaned of all the dried exudate, which
revealed a 1 x 1.5 cm opening near midline
on the right side of the muzzle. 3 -
4 short pieces of grass were removed from
the opening. An oral exam revealed a 7cm
twig and an additional long blade of grass,
both embedded in the mucosal fistula that
communicated with the dorsal opening. A
culture was obtained. The remainder of the
angularis oris flaps appeared healthy.
The patient was placed in right lateral
recumbency. The scar tissue from the rostral
mandible was excised, and the more caudal
tissue was debrided and advanced for closure,
using 3-0 PDS and 3-0 Ethilon. The
oral commissure was incised full-thickness
to allow the ability to open the mouth
without contracture. Buccal mucosa was
sutured to dermis using 3-0 PDS, interrupted
pattern. The skin was closed using
PULSE
MARCH 2022
3-0 Ethilon, interrupted pattern. The right
sided maxillary mucosal defect was sutured
using 3-0 PDS. The animal was re-positioned
in left lateral recumbency, and the
procedure was repeated as on the opposite
side. The mouth was able to expand to 5
cm tip to tip of canine teeth post operatively.
The patient recovered well from surgery
and anesthesia and was discharged the
following day with Marbofloxacin (3 mg/
kg PO q24) pending culture results and
Gabapentin (7.5mg/kg PO q8h). Culture
results returned 3 days later with growth
of Pseudomonas aeruginosa, Morganella
morganii and Methacilin- resistant
staphylococcus pseudintermedius; all three
organisms susceptible to marbofloxacin.
At 2 week post op the patient's incisions
were healed, skin sutures were removed
and there was no discomfort noted when
opening the mouth. The dorsal maxillary
defect had healed and fur was beginning to
grow in a rostral direction over the muzzle
(Figure 2 a,b). Further rechecks were recommended
on an as needed basis.
Binding linear wounds can commonly
be seen in cases of animal cruelty that
involve the extremities or muzzle1
. Large
facial and nasal wounds present a challenge
for surgical repair due to the limited
amount of skin for tension free closure2.3
Numerous reconstructive strategies have
been attempted; however, historically only
the transposition and advancement flaps
have been able to provide sufficient skin
for reconstruction of large defects involving
the rostral nasal skin3
. The angularis
oris axial flap has recently been proven
as a versatile option for facial reconstruction
in both dogs and cats2,4
. Due to their
incorporation of a direct cutaneous artery
and satellite veins, axial flaps can be larger
and longer than subdermal plexus flaps and
have better mobilization than advancement
and transposition flaps5
. The angularis
oris flap is based off of a cutaneous branch
of the angularis oris artery that originates
at the commissures of the lip and then
courses caudally. The flap should be carefully
dissected deep to the panniculus since
it contains the subcutaneous plexus which
is supplied by the terminal branches of the
angularis oris cutaneous vessel6
.
Minor complications have been seen
with this axial pattern flap. However,
according to recent studies, they typically
do not require any surgical revision and
have a 100% success rate2,4
. Complications
can include mild to moderate flap edema,
partial incisional dehiscence and associated
necrosis (typically <1cm), both of which
REFERENCES
1.Reisman, Robert W. " Veterinary forensics: Medical evaluation
of abused live animals. " Shelter medicine for
veterinarians and staff (2012): 383-406.
2.Losinski, Sara L., et al. " Versatility of the angularis oris
axial pattern flap for facial reconstruction. " Veterinary
Surgery 44.8 (2015): 930-938.
3.Yates, G., B. Landon, and G. Edwards. " Investigation
and clinical application of a novel axial pattern flap for
nasal and facial reconstruction in the dog. " Australian
veterinary journal 85.3 (2007): 113-118.
4.Albernaz, Vinicius GP, Michelle L. Oblak, and Juliany G.
Quitzan. " Angularis oris axial pattern flap as a reliable
and versatile option for rostral facial reconstruction in
cats. " Veterinary Surgery (2021)
5.Pavletic MM: Canine axial pattern flaps, using the omocervical,
thoracodorsal, and deep circumflex iliac direct
cutaneous arteries. Am J Vet Res 1981;42:391-406
6.Pavletic MM: Facial reconstruction, in Pavletic MM
(ed): Atlas of small animal wound management and
reconstructive surgery. Ames, IA, Wiley-Blackwell,
2010, pp 433-480
7. Kirpensteijn, Jolle, and Gert Ter Haar. Reconstructive
surgery and wound management of the dog and cat.
CRC Press, 2019.
15
.
the patient experienced2
. The patient did
not initially have the mucosal borders of
the maxilla closed to the subcutaneous layer
of the axial flap, which most likely led to
foreign material being lodged between the
maxillary tissue and the flap tissue causing
disruption of healing6. The dorsal incisional
dehiscence healed rapidly by secondary
intention. Local edema and partial thickness
are considered common complications
due to the subdermal plexus being easily
disturbed during the harvesting of the flap,
despite using delicate tissue handling. These
complications must be expected after the
axial pattern flap is reconstructed.
Angularis flaps can be rotated dorsally
to cover nasomaxillary or maxillofacial
defects, as done in this patient's case;
however, they can also be rotated ventrally
for large mandibular defects2,7
. Cosmetically,
this type of axial flap is commonly
expected to have a puckering or " dog
ear " appearance at the base of the flap2
. It
is important to not excise this tissue since
this could compromise the blood supply.
The puckering will flatten with time and
become unnoticeable. It should be noted
that hair growth on the flap will retain its
original characteristics and will most likely
grow in a rostral direction and be longer
than the naturally occurring haircoat of
the muzzle or chin2
. The surgical procedure
itself, possible common complications,
routine after care, including a Penrose
drain, and postoperative cosmetic appearance
are all important topics to discuss with
clients in dogs receiving angularis oris axial
pattern flaps for nasomaxillary or nasomandibular
reconstructive surgery. P
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