Page 104 - BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery, 2nd Edition

Chapter 7 · Surgery of the larynx

Reported procedures include unilateral arytenoid monitored closely for respiratory distress and given appro-
lat eralization (cricoarytenoid or thyroarytenoid), bilateral priate analgesics. They are maintained on intravenous
VetBooks.ir arytenoidectomy via an oral or ventral approach, modified full recovery but the patient should be observed for clinical
fluids until they are drinking. Soft food may be offered after
ary tenoid lateralization, ventricular cordectomy and partial
signs consistent with aspiration. This is most critical for
castellated laryngofissure, reinnervation of the laryngeal
musculature, nitinol stenting and permanent tracheostomy.
The technique with the best reported outcome is unilat- dogs that routinely eat vigorously and ‘inhale’ their food.
Soft food is recommended because it does not particulate
eral arytenoid lateralization, and this is the most common when chewed. Water should be offered in small shallow
procedure performed. Patients do well with unilateral volumes to slow the rate of drinking. Initially, patients will
surgery and the risk of aspiration pneumonia is minimized. often cough when eating and drinking, which is a normal
Both a cricoarytenoid technique and a thyroarytenoid response to their altered airway.
technique have been described, with good clinical out-
comes (see Operative Techniques 7.1 and 7.2). The
increase in total rima glottidis size with cricoarytenoid Prognosis
lateralization is considerable, but this does not have long- The overall prognosis for laryngeal paralysis is variable,
term clinical significance when compared with thyro - based on the severity of signs and confounding factors.
ary tenoid lateralization. Regardless of the technique With certain lifestyle adjustments, animals can have a good
performed, one or two monofilament non-absorbable quality of life without surgery, but ultimately the clin cal
i
sutures are placed to retract the arytenoid cartilage. A signs will progress as the cricoarytenoideus muscles
swaged-on needle is preferred to reduce the possibility of degenerate. Once clinical signs progress to the point of
fracturing the fragile cartilages. The suture is tightened to affecting quality of life, surgical intervention is strongly
the point of abduction created by the indwelling endo- recommended. Animals have an immediate resolution of
tracheal tube. Extubation and laryngeal examination upper airway obstruction postoperatively. Reported owner
should be performed at that time to confirm appropriate perception of improvement in quality of life is around 90%
placement before closure of the surgical site. with unilateral arytenoid lateralization. Whilst the reported
A final salvage procedure is permanent tracheostomy, incidence of aspiration pneumonia should not be dis-
which effectively bypasses the upper airway altogether missed, with the specific management strategies listed
(see Chapter 8). This is a viable option for animals with above, the risk can be minimized.
significant risk of aspiration pneumonia (myasthenia Recently, geriatric onset laryngeal paralysis and poly-
gravis, diffuse myo pathy or other compounding gastro- neuropathy (GOLPP) syndrome has been described and
intestinal disease) because the laryngeal anatomy is reported. GOLPP is a common problem of older large-
not altered. This technique is fraught with management and giant-breed dogs. It is a disease of the nervous
complications such as stoma occlusion by mucous accu- system, characterized by the slow but progressive degen-
mulation because animals are more prone to inhaling eration of some of the longer nerves in the body. It results
foreign material, require grooming around the tracheal in laryngeal paralysis, oesophageal dysfunction, and hind
stoma and must be prohibited from swimming throughout limb paresis. It is important for pet owners to understand
the rest of their lives. that GOLPP is a progressive syndrome and that dogs vary
widely in their presentation and progression of this neuro-
Postoperative complications and care logical disease. Dogs with more severe oesophageal dys-
function are more likely to develop aspiration pneumonia
The major benefit of the arytenoid lateralization technique with or without surgical treatment of the airway. In dogs
is that no temporary tracheostomy is necessary. There is with mild oesophageal and/or other peripheral nerve defi-
also no disruption of the laryngeal mucosa and therefore cits, unilateral arytenoid lateralization surgery has a good
the risk of scar formation is removed. The risks associated prognosis for return to good, pet quality function. However,
with this procedure are cartilage fracture and suture
other peripheral nerve deficits will continue to progress and
failure if animals are anxious or bark excessively. may become severe enough over the remainder of the pet’s
Postoperative aspiration pneumonia is the most concern-
life to affect their abilities to walk, urinate, and defecate.
ing risk, with reported rates of around 20–25% at some
point during the patient’s life postoperatively. However,
use of a unilateral technique, instead of bilateral, dimin-
ishes the risk of aspiration pneumonia. In addition, certain Laryngeal trauma
strategies can be employed to minimize this risk in the
perioperative period, which is the time of highest risk. Aetiology and clinical signs
With regard to anaesthesia, strict fasting for 8–12 hours
prior to surgery to ensure complete gastric emptying is Blunt laryngeal trauma can result from road traffic acci-
recommended. Premedication with high emetogenic dents, severe straining or harsh pulling on the leash.
properties (hydromorphone) should be avoided. Patients Penetrating laryngeal trauma can be caused by animal
are premedicated with maropitant (1 mg/kg s.c. q24h) bites, sticks, knives or bullets. Traumatic or incautious
and famotidine (1 mg/kg i.v., s.c., i.m. q24h) at the time of insertion of an endotracheal tube can also cause blunt
induction to reduce the risk of vomiting and regurgitation laryngeal injury, especially in cats. Acute injuries to the
in the perioperative period. Dexamethasone sodium phos- larynx can produce laryngeal contusion and obstruction as
phate (0.2 mg/kg i.v. once) is administered to reduce air- a result of haematoma and oedema formation. Respiratory
way oedema during the perioperative period. Patients are obstruction may increase rapidly, and careful observation
intubated swiftly at the time of surgery to reduce the time of breathing rate and pattern and the degree of stridor is
during which their airway is not protected, and endo- mandatory for a successful outcome. Extrinsic penetrating
tracheal cuff inflation is carefully checked. injuries are usually more extensive than suggested by the
Postoperatively, patients are extubated only when they skin wounds, especially when caused by dog bites to
have a strong swallowing/gag reflex. Patients should be the neck. Subcutaneous emphysema and dyspnoea are

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