Page 275 - Clinical Manual of Small Animal Endosurgery

Otoendoscopy 263

prior to the procedure. Some authors advocate the use of glucocorticoids
prior to otoendoscopy in the hope of controlling inflammation in the ear
canals, a common sequela to otitis externa. This should make passage
of the endoscope easier, and should also minimise neurological complica-
tions (transient though they usually are) post endoscopy. This author has
not found this to be of necessity, and indeed, being able to appreciate
the nature of the pathology at its clinically most significant can aid in
interpretation of findings and potentially make histopathology more
rewarding.
Patients should be starved of food for 12 h prior to the procedure in
preparation for general anaesthesia. They should be sedated and induced
for anaesthesia in accordance with standard protocols for the particular
facility as well as with their general health and cardiovascular status.
Given the hyperaesthetic nature of the ears, especially in the diseased
state, general inhalation anaesthesia delivered via endotracheal tube is
indicated. This also provides an increased measure of safety when using
irrigation, to prevent aspiration pneumonia. As otoendoscopy is often
done as part of a more extensive upper airway endoscopic work-up,
including pharyngoscopy and rhinoscopy, it is prudent to have an anaes-
thetic and operative protocol to facilitate doing all of these procedures
at the same time.

Otoendoscopy operative procedure

Patient positioning is at the preference of the operator and often the
design of the operatory room may dictate the patient positioning, loca-
tion of the surgeon and location of the endoscopic equipment tower. Still,
some standardisation is valuable in providing consistent results from case
to case. It is advisable the procedure be performed on a wet table or
surgical sink table as often copious amounts of irrigant are used. This
facilitates keeping the patient warm and dry and minimises flooding the
floor of the operating theatre.
The patient is usually positioned in lateral recumbency with the
affected side (or the side to be examined first) uppermost. The endoscopy
equipment tower is positioned along the dorsal aspect of the patient, at
approximately the level of the head, ideally at 11 o’clock to the top of
the skull. The surgeon usually stands at approximately 6 o’clock given
this orientation. This provides for the most ergonomic positioning of the
operator and equipment relative to patient. Occasionally, depending on
the specific anatomy of a given patient, it may be beneficial to place a
rolled towel under the head to allow the muzzle to point in the down-
ward direction, while slightly elevating the dorsal part of the head. This
brings the vertical canal into more linear approximation with the angle
of the endoscope and allows for drainage of irrigant out the nose, rather
than back into the pharynx.