Page 24 - Clinical Manual of Small Animal Endosurgery

12 Clinical Manual of Small Animal Endosurgery

shaft, and their tip is not always visible; consequently sample collection
using this technique requires considerable practice.
High fluid rates are required to flush the nasal cavities, to obtain
increased optical space and to flush away haemorrhage and discharge
from the visual field. Vigorous flushing can also be exploited to obtain
biopsy samples.
Another diagnostic and therapeutic application achievable with the
basic rigid-endoscopy kit is transurethral cystoscopy in female dogs and
cats. The preferred endoscope again has a diameter of the 2.7 mm (or
1.9 mm for cats and dogs less than 5 kg), is 18 cm long with a 30° viewing
angle, and is used with a cystoscopy sheath. Although the sheath increases
the outer diameter (the most used sheath is the 14 French), its use is
preferred for the presence of fluid-inflow and -outflow channels, which
allow fluid infusion to increase the optical space and avoid clouding of
the operating field.
An instrument channel is also present, useful for insertion of biopsy
forceps and various operating instruments. Grasping forceps and basket
catheters are commonly used for removal of small uroliths and foreign
bodies such as sutures protruding in the bladder lumen, whereas energy-
assisted devices allow removal of intraluminal inflammatory polyps and
masses, and correction of mucosal defects such as ectopic ureters and
strictures.
This cystoscope permits examination of the urethra and the bladder
of bitches from 5 to 20 kg. For larger bitches, due to urethral length, a
cystoscope with a longer shaft (30 cm, with a diameter of 3.5–4 mm) is
necessary for bladder examination.
A 1.9 mm rigid endoscope allows examination of the bladder and
urethra in bitches smaller than 5 kg, queens, and male cats after perineal
urethrostomy. A flexible endoscope is necessary for male dogs and cats.
Laparoscopic-assisted cystoscopy is also useful for diagnostic purposes
and treatment, for example when the presence of large uroliths does not
allow transurethral removal.
A more specialised procedure feasible with rigid endoscopes is tran-
scervical catheterisation in the bitch, useful for collection of uterine
samples and for insemination (Wilson, 1993, 2001). Due to vaginal
length in bitches, a specialised 29 cm-long telescope is necessary. A cys-
toscope with a 30° oblique viewing angle and an outer-diameter 3.5 mm
sheath is typically used.
Finally, in the last 20 years rigid endoscopes have been used more and
more often to minimise the extent of the surgical approach to the
abdomen, thorax and joints. These techniques (laparoscopy, thoracos-
copy and arthroscopy, respectively) allow evaluation, biopsy and more
advanced surgical procedures via the insertion of a telescope through a
small incision in the surgical site.
As for all the other procedures examined so far, the core pieces of
equipment required are the same (camera system and light source).