Veterinary Endoscopy Training

Exotic Animal Endoscopy Training

Exotic Animal Endoscopy Course
© Stephen Hernandez-Divers, The University of Georgia

Exotics Equipment

Flexible Endoscopes

Flexible endoscopes are most useful for respiratory endoscopy in snakes or gastro-intestinal endoscopy in many species. The main disadvantage of the flexible, fiber-optic endoscope is the poorer image quality compared to rigid scopes of a similar diameter. A 100cm, 2.5mm flexible broncho-fibrescope with 1.2mm instrument channel (60003VB; Karl Storz) is useful.  There is also a 1.0mm semi-rigid endoscope available that is particularly useful for very fine work (11503; Karl Storz).

The 2.5mm x 100cm fiberscope – particularly useful for upper respiratory and gastrointestinal endoscopy in larger exotic species, esp. snakes (courtesy of Karl Storz)

Rigid Endoscopes

The compact body size of most pet exotic species coupled with the coelomic body design of birds and reptiles does lend them to rigid endoscopy. The majority of rigid scopes incorporate a convex glass lens system, in which the small glass lenses are separated by large air spaces. In contrast, the rod lens telescope, invented by Professor Hopkins, utilizes comparatively longer rods of glass and smaller air spaces. The advantages of the rod lens system are greater light transmission, better image resolution, wider field of view and image magnification. The author has used various makes and models but is of the opinion that rod lens scopes are superior, and currently prefers the diagnostic system designed by Taylor in association with Karl Storz Veterinary Endoscopy (Taylor, 1993). The system originally designed for birds is equally applicable to reptile medicine and centers on a 2.7mm Hopkins telescope with 30-degree oblique view (64018BSA). The 30-degree oblique view not only enables a straight on view but, by simply rotating the scope around its longitudinal axis, a much greater field of vision can be obtained.

The author has been unable to locate a manufacturer, other than Karl Storz, that can also provide a fully integrated range of accessories designed for the exotic animal veterinarian. The 2.7mm Hopkins telescope is best used with a 14.5F operating (Taylor) sheath with 5F instrument channel (67065 CC), which provides two ports for air and/or water inflation, aspiration and irrigation. The instrument channel permits the use of various endoscopic instruments, the most useful of which are the flexible scissors (62501EK), 5F flexible grasping forceps (67161T), 5F elliptical cup flexible biopsy forceps (67161Z) and fine aspiration/injection needle with Teflon guide (67071X). The 5F flexible biopsy forceps are used to harvest tissue samples for histopathology and microbiology. The small sample size permits the taking of several biopsies, the taking of sequential biopsies to monitor progress and the use of endoscopic biopsy techniques in patients under 100g. The 5F grasping forceps are useful for manipulating tissues, debridement and foreign body retrieval. The fine aspiration/injection needle can be used for remote aspiration, irrigation and drug administration.

The standard endoscope (above) and Hopkins telescope design (below). The glass rods in the Hopkins telescope provides a larger image, greater light transmission, and improved clarity of vision (courtesy of Karl Storz).

Left: 2.7mm telescope and 14.5 Fr Taylor operating sheath. Right: Comparison between 0^o and 30⁰ telescopes (courtesy of Karl Storz).

Left: Comparison between an exam/protection sheath and an operating sheath with an instrument channel.

Right: The telescope housed within the Taylor operating sheath (courtesy of Karl Storz).

Left: Endoscopic instrument in situ within the telescope-sheath system. This system enables a single surgeon to perform endoscopy procedures including biopsy. Right: Endoscopic scissors, needle, biopsy and retrieval forceps can all be used with the 2.7mm system (courtesy of Karl Storz)

Light Sources, Cameras and Recording Equipment

There are two major types of light source available, the cheaper tungsten-halogen and more expensive, rare-earth xenon. Halogen is sufficient for rigid endoscopy using the eyepiece, but the xenon source is preferred for documentation. More powerful light sources are essential when dealing with video endoscopy and the reduced light transmission of fine flexible endoscopes. The light source is connected to the endoscope via a flexible, fiber-optic cable. The efficiency of light transmission is reduced as the cable length increases. A xenon light source with a dedicated endoscopy camera and some form of documentation capability (e.g. video tape, digital video, digital still image capture, still image print-out) is recommended.

Xenon light sources, left – basic unit (courtesy of Karl Storz), right – more advanced unit with digital display and standby feature

Endoscopy cameras attach to the eye-piece and greatly improve endoscopic ability. Left - basic cameras come with a focusing ring (courtesy of Karl Storz), right - more advanced models possess focus and zoom functions, and a variety of other digital features.

Recording is important for case records and educating/marketing.

Equipment Preparation

It is essential to use properly sterilized equipment to prevent post-endoscopy infection. The two practical options are gas sterilization (e.g. ethylene oxide or hydrogen peroxide) or cold sterilization (e.g. 2% glutaraldehyde solution). Endoscope equipment should not be soaked in any solution for more than 30 minutes, and always follow the endoscopy manufacturer's recommendations. Many modern scopes are autoclavable but it is essential that only autoclave-safe endoscopes are heat-pressure sterilized otherwise irreversible damage will occur.

Patient Preparation

General anesthesia is recommended for all endoscopy procedures. Examination of the buccal cavity, esophagus, avian crop, trachea and cloaca may be possible in the conscious or sedated patient using a mouth gag or other appropriate restraint, but the author prefers general anesthesia and not to risk damage to the equipment, patient or staff.

Endoscopy is a surgical technique that should be performed using sterile techniques within the controlled environment of a veterinary clinic or practice. Carrying out multiple endoscopy procedures in different birds from different owners, breeders and petshops in a non-sterile environment is a recipe for disaster. Apart from amplified anesthetic and surgical risks, post-operative complications, including the spread of serious diseases like Chlamydia (Chlamydophila), psittacine beak and feather disease virus, and polyomavirus are greatly increased.