Page 39 - BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery, 2nd Edition

BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery

Malignant melanoma may be resected locally with
tumour-free margins. However, regional or distant meta-
VetBooks.ir are more difficult to achieve, making local recurrence
stasis is common. Tumour-free margins for fibrosarcoma
likely. Low-grade mandibular osteosarcomas in dogs tend
to be associated with a longer survival time than long-
bone osteosarcomas.

Cheek and lip

Chewing lesions

Chewing lesions may result from chronic self-induced
trauma to the sublingual mucosa or the labial and buccal
3.5 Fibrosarcoma of the left mandible in a dog. mucosa along bite planes. Usually, no treatment is required.
Surgical resection is indicated for excessive hyperplastic
tissue that continues to be traumatized.
Surgical management
Lacerations
Animals with no radiographic signs of distant metastasis are Initial wound management includes debridement and copi-
considered for aggressive therapy. The concept of complete ous lavage. Lacerations are sutured with separate layers
local excision of the tumour, followed by (or concurrent with) for apposition of the mucosa and skin. Delayed primary
chemotherapy and/or immunotherapy, has achieved marked closure is indicated when the wound is grossly contami-
acceptance in human oncological therapy and is being nated, purulent, extensively devitalized, oedematous or
applied in veterinary medicine. This multimodal treatment is
usually well tolerated by dogs and cats, leaving conserv- inflamed, and is performed 3–5 days after injury.
ative management for only the more debilitated and/or
geriatric patients. Such treatment plans are best designed Lip avulsion
and executed at specialist centres that have expertise in all
the required disciplines (Marconato et al., 2013). Avulsion injuries of the lips may occur after a traffic acci-
dent or a fall from a high-rise building (cat), when the lip is
The goal of surgery is curative resection, cytoreduction
inadvertently stepped on by someone or when the animal
or palliation. The ideal surgical procedure is one that offers
the greatest possibility of cure, restores or maintains func- is grasped and lifted at its snout by another animal (dog).
These injuries are more common in cats than in dogs, and
tion and has an acceptable cosmetic result. Benign neo-
plasms which do not involve bone are excised surgically. the lower lip is more often affected (Figure 3.6).
The wound should be gently debrided and rinsed. The
For malignant neoplasms, a 2 cm margin of tumour-free
tissue is recommended, often necessitating ostectomy as lip is then replaced and kept in position with simple inter-
rupted sutures in areas with enough soft tissue remaining,
part of the operative procedure.
Neoplasms with radiographic evidence of local bone and with large horizontal mattress sutures that can be
passed around tooth crowns. Reducing dead space is
metastasis require surgical procedures including extensive
maxillectomy (see Operative Technique 3.1) and total man- important. Subcutaneous tissue is attached ventrally to
the intermandibular tissues and the mandibular symphysis
dibulectomy (see Operative Technique 3.2) (White, 2003b).
These procedures maximize the removal of the entire bony with absorbable suture material. Plastic tubing can be
used to form tension-relieving sutures. Surgical drains are
component of the neoplastic process. Segmental proce-
dures resulting in partial maxillectomy or mandibulectomy rarely required (Reiter and Lewis, 2011; Reiter, 2012).
without intraoperative frozen section analysis of tissue
margins risk incomplete resection due to intrabone peri-
neural and microvascular metastatic routes. This is of
particular importance for mandibular lesions, in which
case total mandibulectomy may be preferred to partial or
segmental mandibulectomy, as cosmesis and function are
acceptable despite a greater degree of resection.
Prognosis
Oral malignancies often have a guarded to poor prognosis,
which may be affected by size of the lesion, age of the
patient and species.
Younger dogs with SCC rostral to the second pre-
molars have a better prognosis than older dogs and those
with neoplasms in other locations. Cats with SCC have a
shorter tumour-free interval than dogs, regardless of the
type of treatment. The most positive prognosis for oral
SCC in dogs is attained when both surgery and radiation
therapy are combined. Treatment of SCC of the root of the Lo er lip avulsion in a kitten after motor vehicle trauma.
tongue in cats is strictly palliative. 3.6

30

Ch03 HNT.indd 30 31/08/2018 10:39