Page 105 - BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery, 2nd Edition

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

the most important indicators of a penetrating laryngeal
wound, but the perforation may include the trachea, pharynx
VetBooks.ir Diagnostic imaging and laryngoscopy
and oesophagus, vessels and nerves, and neck muscles.

Laryngoscopy should always be performed to assess the
presence of intralaryngeal perforations and lacerations, to
estimate the degree of obstruction caused by haematoma
and oedema, and to determine the need for tracheostomy
tube placement. After thorough inspection, patients can
be intubated with a small tube before diagnostic imaging
commences. Diagnostic imaging is always recommended
after acute injury as it will help detect fractures of
the hyoid bones and laryngeal cartilages and will allow
assessment of concurrent pulmonary contusions or
pulmonary oedema. More detailed information can be
obtained using computed tomography (CT) or magnetic
resonance imaging (MRI).
Laryngoscopic view of a large red granulomatous mass in a
7.4
Treatment cat with chronic laryngitis, mimicking neoplastic disease.
Affected dogs or cats should be hospitalized and moni-
tored when there are no fractures of the larynx and the plasmacytoma, melanoma, granular cell tumour, undif-
laryngeal mucosa is seen to cover the laryngeal cartilages. ferentiated carcinoma, fibropapilloma and fibrosarcoma,
In cases of severe dyspnoea, if a significant increase in mast cell tumour, adenocarcinoma and squamous cell
swelling in the post-imaging period is expected, or if non- carcinoma. Most laryngeal tumours are very locally inva-
dislocated laryngeal fractures are seen, a tracheotomy sive and have a significant metastatic potential. Feline
should be performed. laryngeal neoplasms are most commonly lymphomas,
Fractures with discontinuity of the laryngeal cartilages although squamous cell carcinoma and adenocarcinoma
should be repaired immediately or granulation tissue will have been reported. Except for laryngeal oncocytomas,
cause contraction and narrowing of the laryngeal passage- which appear to occur in younger mature dogs, most dogs
way. Associated soft tissue injuries of the skin, subcuta- and cats with laryngeal cancer are middle-aged to older.
neous tissues and pharyngeal and laryngeal muscles Neoplasms such as lymphoma (Figure 7.5) and thyroid
necessitating repair can be attended to in the same adenocarcinoma may secondarily invade the larynx,
although the latter usually invades the trachea.
surgical session. Surgery is always recommended for
patients with penetrating injuries, such as after bite inci-
dents or stick injury, to retrieve foreign material, debride Diagnosis
necrotic tissue, repair fractures and soft tissue trauma and
drain the area, as bacterial contamination inevitably will be Dyspnoea and a progressive change in voice or bark
present. For all injuries, a ventral midline approach is (hoarseness and ‘breaking voice’) are usually the presenting
recommended for exploration of the neck. Any obviously clinical signs of animals with laryngeal cancer, although
devitalized tissue or heavily infected tissue should be exercise intolerance and dysphagia are sometimes reported
removed if possible. Lacerations of the pharynx, larynx, as well. The laryngeal stridor is usually only inspiratory at
trachea and oesophagus are closed after careful debride- first; however, when the obstruction is large enough it will
ment. Thorough flushing of the area is performed to be both inspiratory and expiratory.
decrease bacterial contamination further. Continued post-
operative drainage should be provided by placement of
active or passive wound drains. Broad-spectrum anti -
bi otics and analgesia are given and the patient is hospital-
ized for careful monitoring during the first few days.

Laryngeal tumours

Benign masses, cysts and neoplastic disease in the
larynx are rare in dogs and cats. Cysts are very rare, but
can be recognized by radiographic and ultrasonographic
i
exam nation of the larynx and localized precisely by
laryngoscopy, when they can also be incised and drained
or surgically excised. In cats, obstructive laryngeal
disease with granuloma formation can mimic neoplastic
disease, and the conditions need to be differentiated by
biopsy and histopathology (Figure 7.4).
Reported canine laryngeal tumours include rhabdo-
myoma (oncocytoma), lipoma, osteosarcoma, chondroma, Laryngoscopic view of a large laryngeal lymphoma
myxochondroma and chondrosarcoma, extramedullary 7.5 obstructing the entire rima glottidis in a cat.

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