Page 539 - Clinical Small Animal Internal Medicine

507

VetBooks.ir

49

Gastrointestinal Endoscopy

Craig Ruaux, BVSc (Hons), PhD, MACVSc, DACVIM (SAIM)

School of Veterinary Science, Massey University, Palmerston North, New Zealand

Gastrointestinal endoscopy is an attractive diagnostic Endoscopy Equipment Options
tool for many gastrointestinal disease cases presenting to
companion animal practitioners. This technique can All visual light endoscopes operate by channeling light
allow direct visualization of the gastrointestinal mucosa from an external source, via fiberoptic light guides, to the
in the esophagus, stomach, upper part of the small intes- area of interest. This light then illuminates the area being
tine, colon, and distal ileum. While some of these proce- examined, and an image is formed. The actual mecha-
dures are straightforward, entry into the upper part of nism leading to image formation is typically from one of
the small intestine and the distal ileum can be quite chal- two options: either the use of additional fiberoptic ele-
lenging in some patients. ments to return the light via an objective lens at the oper-
Endoscopy is often viewed as a much less invasive ating end of the scope (these are commonly called
method of obtaining gastrointestinal mucosal biopsy fiberscopes), or via direct capture of a digital image using
samples than can be achieved with either exploratory an imaging chip at the distal, patient end of the instru-
laparotomy/celiotomy or laparoscopy‐assisted full‐ ment (videoendoscopes) (Figure 49.1). Fiberscopes rep-
thickness biopsies. While endoscopic biopsy has an resent an older technology, and are usually cheaper than
advantage of lower risk and less perioperative morbidity, equivalent‐sized videoendoscopes, but they do have sig-
the quality of endoscopic biopsy samples is often found nificant shortcomings. Fiberscopes are more affected by
wanting. This is particularly the case with the use of fiber breakage, as the image depends on light successfully
smaller endoscopes with very narrow biopsy channels traveling in both directions. The image is often quite dim,
that limit the size of the biopsy instruments that can be as there are more light losses involved with transit along
passed. the length of the scope and back. The generation of medi-
With refurbished flexible endoscopy systems becom- cal records with these endoscopes is also more difficult,
ing more readily available on the market, and at reason- requiring an accessory camera attached to the eyepiece,
able prices, there is increasing utilization of these representing another potential point of failure. While fib-
instruments and procedures in generalist practices. erscopes were long the mainstay of flexible endoscopy in
Competence in flexible gastrointestinal endoscopy veterinary medicine, videoendoscopes are preferable due
requires meaningful amounts of hands‐on practice, and to superior image quality, greater ease of use, and greater
guidance from an experienced operator in a hands-on ease of generation for permanent medical records.
training environment is the best way to achieve compe- Endoscopes used for gastrointestinal procedures
tence in a short period of time. The purpose of this chap- should feature four‐way tip deflection, allowing the devi-
ter is to provide an overview of flexible endoscopic ation of the tip left or right of center and up or down. Tip
equipment types, correct handling and manipulation of deviation is defined relative to the midline of the control
the endoscope, methods for obtaining biopsies, a general handle, with the control cluster in the operating hand.
overview of the steps for several endoscopic procedures, Some smaller scopes, designed for airway examination
and the use of flexible endoscopy for some minimally rather than gastrointestinal endoscopy, have only up and
invasive therapeutic procedures such as feeding tube down deflection controls while left to right turns are
placement and foreign body retrieval. made by turning the entire endoscope.

Clinical Small Animal Internal Medicine Volume I, First Edition. Edited by David S. Bruyette.
© 2020 John Wiley & Sons, Inc. Published 2020 by John Wiley & Sons, Inc.
Companion website: www.wiley.com/go/bruyette/clinical