The U.S. has more than 100 million exotic pets, compared to about 70 million dogs and 80 million cats.1 Unlike domestic animal medicine, few serologic diagnostic tests are available, and therefore a definitive diagnosis often relies upon the demonstration of a host pathological response (e.g. histopathology) and identification of the causative agent (e.g. microbiology, parasitology, toxicology).
Indeed, because of the difficulties of achieving a definitive diagnosis, many exotic-animal diseases have traditionally been identified to organ level only, such as avian liver disease and iguana renal disease, or generalizations have been made: All rabbits with rhinitis or pneumonia have Pasteurella multiocida.
Endoscopy offers a minimally-invasive means of collecting biopsies and hence making a definitive diagnosis, which in turn enables more accurate and targeted therapy and improved treatment success. Today, with cost-effective endoscopy equipment commonly available, it is difficult for veterinarians to offer an appropriate standard of care for exotic pet clients without an endoscopy service.
Financial constraints in most small-animal practices imposed a choice: Either buy a rigid endoscopy system or a flexible system because few could afford both. The recent surge in rigid and flexible endoscopy has certainly been helped by the availability of a camera and light system that can be used with both rigid and flexible endoscopes (Karl Storz Veterinary Endoscopy America Inc).
While there have been other notable advances in both equipment and techniques over the past decade, the mainstay of rigid diagnostic endoscopy in exotic pets remains the human pediatric cystoscopy system that was first modified for use in birds.2
However, the introduction of basket retrieval devices, polypectomy snares and radiosurgical devices have further expanded the endoscopy repertoire. The basket retrieval device has been useful for foreign body removal from the crop, provenriculus and ventriculus of birds, while polypectomy snares have been for orchidectomy in birds.
While endoscopic debridement of small granulomas from the avian syrinx and air sacs have been described previously, radiosurgical needles and diode lasers can be used through the operating channel for ablation. They also can be used for treating cloacal papillomas as they can operate within a fluid environment using saline infusion.
Birds, reptiles and most exotic mammals mask clinical signs, and clinicopathologic data are often poorly diagnostic. Therefore, internal examination with biopsy has become a primary diagnostic tool in many species following medical stabilization.
Coelioscopy (reptiles, birds and fish) and laparoscopy (mammals) enable examination and biopsy of most soft tissues, often through a single-entry approach.2–5 Indeed, few exotic animal specialists would advocate traditional surgery for a liver or kidney biopsy, given the ease and proven success of endoscopic approaches.6–9
In birds, the left lateral approach to the airsac system provides access to the heart, liver, lung, kidney, adrenal, spleen, gonad and serosal surfaces of the proventriculus and ventriculus. The spleen is often best seen from a right approach.
Similar visceral examination is possible in reptiles, although tilting tables are preferred for mammals to facilitate visceral displacement. Stomatoscopy, rhinoscopy and tracheobronchoscopy have changed the author’s approach to oral, nasal and respiratory diseases of rabbits and rodents, and even thoracoscopy has proven of value for the evaluation of mediastinal masses.4,10
Coelioscopy in fish has recently been shown to cause less morbidity and mortality compared to coeliotomy.7
Probably the area of greatest development has been the evolution of the 2.7 mm telescope system into a multiple-entry endosurgical system for birds, reptiles, exotic mammals and fish. This has centered on the use of human pediatric laparoscopy equipment, including lightweight graphite/plastic cannulae and 3 mm instruments to create a second and third entry into the body cavity, with triangulation to perform surgery endoscopically.3,11
While the same size of many exotic pets presents obvious challenges, an increasing array of procedures has revolutionized the approach to these animals.
Reproductive diseases of female turtles remain common, and yet preventive sterilization was seldom recommended due to the invasive nature of traditional approaches through the shell. However, recently an endoscope-assisted technique has been described that enables adult female turtles to be ovariectomized through a soft tissue window in front of the pelvic limb.12 This procedure uses the endoscope to visualize and assist with the exteriorization of ovaries, which are then removed using traditional external techniques; however, other procedures may be performed completely internally. In pigeons and parrots, true endosurgical salpingohysterectomy and orchidectomy have been successfully performed.11,13
Clinically, these animals appear to have recovered significantly faster compared to traditional procedures. Similar gonadectomies are now possible in lizards.3
The common theme that permeates this article is that minimally-invasive procedures result in reduced morbidity and mortality, faster healing, quicker return to normal feeding and behavior, and reduced post-operative complications.14
These advances have found increasing support among veterinarians and their clients, who are concerned with traditionally invasive surgery. Indeed, many owners are personally aware of the benefits of endoscopy through family experiences.
Given the increasing expectations of clients and the complexities of exotic animal medicine, endoscopy’s future in clinical medicine seems assured. Veterinarians interested in learning endoscopic techniques should consider a course that includes hand-on practical learning. Such training often is available at major conferences, and the University of Georgia offers a two-day course every December. (Click here for details or e-mail firstname.lastname@example.org)
Stephen J. Hernandez-Divers, BVetMed, DZooMed, MRCVS, Dipl. ACZM, is an associate professor of zoological medicine at the University of Georgia.
2. Taylor M. Endoscopic examination and biopsy techniques In: Ritchie BW, Harrison GJ,Harrison LR, eds. Avian Medicine: Principles and Application. Fort Worth, Florida: Harrison Bird Diets International, 1994;327-354.
9. Hernandez-Divers SJ, Stahl S, Stedman NL, et al. Renal evaluation in the green iguana (Iguana iguana): Assessment of plasma biochemistry, glomerular filtration rate, and endoscopic biopsy. J Zoo Wildl Med 2005;36:155-168.
13. Hernandez-Divers SJ, Stahl SJ, Wilson GH, et al. Endoscopic orchidectomy and salpingohysterectomy of pigeons (Columba livia): an avian model for minimally invasive endosurgery. J Avian Med Surg 2007;21:22-37.
Dr. Stephen Hernandez-Divers is not salaried with any equipment manufacturer, and all equipment that he uses in clinical practice was purchased. In keeping with the Royal College of Veterinary Surgeons guidelines to professional conduct, he does not endorse any specific manufacturer.