Page 16 - Clinical Manual of Small Animal Endosurgery

4 Clinical Manual of Small Animal Endosurgery

MEDIFIX

Fig. 1.4 Line drawing of an operating telescope. The offset eyepiece
allows straight rigid instruments to be passed in parallel with the scope.

and have a slightly steeper learning curve. As the angled view is opposite
the insertion of the light guide cable, when the operator holds the endo-
scope with the light cable up, the surgeon has a more ‘anatomical’ spatial
orientation. Telescopes are available with viewing angles up to 70°, and
even 120°; the forward-oblique 30° ones are a good compromise between
increase in the field of view and ease of orientation, and are particularly
indicated for more advanced procedures such as thoracoscopy. Scopes
with viewing angles over 30° are used for particular purposes in human
surgery but are rarely used in animals.
Some telescopes (operating or single-portal scopes) have a working
channel (Fig. 1.4), which can be up to 5–6 mm in diameter, and allows
the introduction of instruments for biopsy or surgical procedures. These
scopes are usually wider and longer than conventional ones, and their
eyepiece is offset. These telescopes are used in human surgery and are
designed for specialised applications; they are rarely used in animals.
In small animal practice, two scopes are useful for performing the
majority of endoscopic procedures: a 2.7 mm, 18 cm-long scope and a
5 mm, 30 cm-long scope. The 2.7 mm scope is used for rhinoscopy, otos-
copy, cystoscopy in female dogs, and arthroscopy, and can be used for
endoscopy in birds and exotic species. It should have a 30° angle of view.
The 5 mm scope is ideal for laparoscopy and thoracoscopy of any size
dog or cat. If only one 5 mm scope is chosen, a 0° scope is most suitable.
An outer sheath with channels for fluid influx/efflux and instruments is
useful for cystoscopy and otoscopy and is used with the 2.7 mm scope.