Page 120 - BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery, 2nd Edition

Chapter 8 · Surgery of the extrathoracic trachea

Indications: These have not yet been completely deter- Masses causing tracheal
mined. Stenting may be indicated in animals that are obstruction
VetBooks.ir sive intrathoracic tracheal collapse or are poor surgical External compression is caused by an extramural mass
refractory to aggressive medical management, have exten-
candidates. The role for stenting in animals with cervical
collapse alone is unclear and it is usually avoided unless
lymphadenopathy or neoplasia (e.g. thyroid carcinoma or
surgery is contraindicated or denied. lesion, such as a haematoma, abscess, cyst, granuloma,
oesophageal neoplasia). An intraluminal mass may be a
Prostheses: A review of different stents and materials is haematoma, abscess, cyst, eosinophilic granuloma, inflam-
beyond the scope of this chapter. The most commonly used matory polyp, tracheal neoplasm, parasitic reaction (e.g. to
devices include mesh nitinol self-expanding metallic stents Oslerus (formerly Filaroides) osleri), or a foreign body.
(e.g. Vet Stent-Trachea™, Figure 8.12), or more uncommonly Obstructive diseases cause increased airway resis-
devices made of stainless steel (e.g. Wallstent™) or woven/ tance at the point of the obstruction. Clinical signs depend
braided nitinol (e.g. Ultraflex stents). on the degree of airway obstruction. Severe obstruction
results in an obstructive breathing pattern, with a slow
inspiratory phase followed by a more rapid expiratory
Sheath with
Partially deployed stent constrained phase. Many animals present with stridor and a rattling
stent inside noise in the throat. Coughing may also occur. Respiratory
distress is usually obvious.

artially deployed et tent-Trachea ithin its delivery
8.12 sheath demonstrating the lo -profile delivery system and Tracheal foreign bodies
stent foreshortening. Some tracheal foreign bodies can be removed endoscopi-
cally. Holding an anaesthetized patient head down and
Technique: Briefly, an oral/laryngeal examination and tapping the thorax gently may occasionally remove a
trach eoscopy are performed under sedation, followed by
foreign body or may move it into a more proximal position
rapid induction of anaesthesia. The patient is placed in for easier tracheoscopic removal. Surgical removal, via
lateral recumbency on the fluoroscopy table. Perioperative
tracheotomy, is indicated for foreign bodies that cannot
corticosteroids and antibiotics may be used. If available, a be removed by tracheoscopy. Alternatively, graspers, or
marker catheter is passed through the mouth into the
stone baskets or snares, can be used under fluoroscopic
oesophagus, to the level of the thoracic inlet, to account guidance in patients with airways too small to permit
for magnification on the recorded images. The endo-
endoscopic removal, as described by Tivers and Hotston
tracheal tube is retracted until it is just caudal to the Moore (2006) (Figure 8.14).
larynx. Positive pressure ventilation to 20 cmH 2O is gener-
ated whilst a radiograph including the cervical and
thoracic trachea is obtained. The degree of magnification Tracheal neoplasia
is calculated in order to determine the actual diameter of
the trachea. A stent of appropriate diameter and length is Tracheal neoplasia is rare in the dog and the cat. In both
species, tracheal neoplasia includes lymphoma, osteo-
chosen and the location of collapse previously determined
via fluoroscopy in the awake animal is noted (in general sarcoma, chondrosarcoma, fibrosarcoma, adenocarci-
most of the trachea is stented). The stent is deployed noma, squamous cell carcinoma and mast cell tumour. In
under fluoroscopic guidance (Figure 8.13). More complete the cat, lymphosarcoma and squamous cell carcinoma
discussions of tracheal stent placement can be found in predominate. Benign tracheal neoplasia includes plasma-
Moritz et al. (2004) and Weisse (2015). cytoma, ostechondroma and tracheal polyps. Osteo-
chondral dysplasia of the trachea is a condition seen in
Results: Two studies report clinical improvement in young dogs; lesions stop growing at skeletal maturity and
75–90% of animals treated with intraluminal self-expanding surgical resection of the lesion typically achieves cure.
stainless steel stents (Moritz et al., 2004). Most immediate Clinical signs of tracheal neoplasia include paroxysmal
complications were minor, including coughing, tracheal coughing of weeks’ to months’ duration, dyspnoea which
haemorrhage and pneumomediastinum. A perioperative progressively worsens and the presence of stridor. Retching
mortality rate of approximately 10% has been reported, due with production of haemorrhagic discharge may occur
to aspiration pneumonia, worsening clinical signs, incorrect occasionally. Large masses may be palpable on examin-
stent placement and emphysema. Long-term complications ation of the neck. Respiratory signs are usually only evident
included excessive granulation tissue, stent shortening, when 50% of the tracheal lumen is obliterated, so in general
stent fracture and progressive tracheal collapse. patients present with advanced disease.

(a) (b) (c)
erial lateral fluoroscopic images a during cm O positive pressure ventilation for determination of maximal tracheal diameter;
8.13
(b) during placement of a tracheal stent delivery system through the endotracheal tube and within the tracheal lumen; (c) immediately
following stent deployment.

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