Seize The Moment
This Cavalier King Charles spaniel suffered from zinc toxicity due to coin ingestion.
(Photo courtesy of Dr. Kirk Ryan)
Advanced diagnostic procedures such as endoscopy and ultrasound are sometimes viewed as referral-only procedures. However, improvements in training and equipment have created a growing niche for these tools in general veterinary practice.
With proper training and advice, practitioners may hone their skills to a level that allows the practical use of endoscopy for some cases and promotes good decisions regarding referral for other cases. Even if your practice goals don’t include the purchase of endoscopy equipment, you may benefit from becoming more familiar with this procedure.
The initial cost outlay for veterinary endoscopy equipment varies. The purchase price for a general setup ranges from $5,000 to $20,000, whereas experienced endoscopists may seek equipment costing from $30,000 to $50,000 or more.
Some vendors provide attractive equipment leases and lease-to-purchase options. Used and reconditioned equipment is often available at a lower cost.
In addition to cost, however, veterinarians should factor in the service and support available from endoscopy vendors familiar with the veterinary market. These vendors can be an excellent resource for proper care and use of the products.
Technicians trained in the cleaning and storage of endoscopy equipment can add years to the life of an endoscope. In addition, endoscopy vendors may be able to refer you to national or regional continuing education workshops that feature the product you are buying.
The basic components of a flexible endoscopy system include:
- A high-intensity light source.
- An air/water/suction pump.
- An endoscope.
The endoscope contains an instrument channel through which biopsy devices and other tools may be passed.
Basic fiberoptic endoscopes transmit the image from the end of the scope to an eyepiece located in the handset. The endoscopist views the image by looking into the eyepiece. To view a larger image, a camera may be attached to the eyepiece to transmit the image to a video monitor. However, these cameras can be bulky and add to equipment setup requirements.
Contemporary video endoscopes electronically transmit high-quality images directly to a monitor. Video capability allows veterinarians and technicians to view the images as a group in real time, which enhances teaching, learning and collaboration.
Regardless of the endoscope selected, image quality is dependent upon the light source and the fiberoptic properties of the endoscope. Halogen or xenon light sources of 150 to 300 watts are preferred.
When ordering instruments to be used with a scope, make sure to consider the length and channel diameter of your endoscope. Instruments that are too short or that do not fit the channel cannot be used and may damage your equipment. A small-diameter scope facilitates passage through turns and narrow areas (i.e. pylorus), but may have a small-diameter instrument channel.
For foreign-body removal, it is wise to have a number of retrieval tools to deal with the variety of unusual items ingested by dogs and cats. These instruments are passed through the channel within the center of the scope and used to manipulate and hold on to material while the scope is withdrawn from the GI tract.
Retrieval instruments range from simple forceps to more complicated nets and baskets. Remember that most items in the stomach are smooth and wet, which poses a problem for simple removal. In addition to standard grasping forceps, rat-tooth forceps and a rubber-tipped forceps provides friction and traction.
A variety of nooses, nets and baskets may be used to surround and enclose objects to be removed. Rigid alligator forceps with teeth may be passed alongside the scope to deal with firmly lodged esophageal foreign bodies. Such instruments provide necessary leverage and force, but must be used with care to avoid damaging the esophagus.
Biopsy instruments should not be used for foreign-body retrieval because they typically fragment the material rather than grip it. They also dull easily when used for this purpose. For intestinal biopsy, forceps passed through the endoscope pinch the mucosa and enclose the biopsy within a cup. Various types of endoscopic biopsy forceps are available to suit the preferences of the veterinarian.
Examples include smooth cup forceps (with or without a center spike) and toothed cup forceps with serrated edges. A minimum of 10 endoscopic biopsies should be obtained from each examined area because endoscopic biopsies are small and superficial.
Endoscopic biopsies also tend to curl on themselves, creating unusual tissue alignments that complicate interpretation by pathologists. To avoid this problem, biopsies should be carefully placed inside labeled formalin-soaked, foam-lined cassettes.
The use of endoscopy to evaluate intestinal disease requires greater skill and familiarity with the appearance of normal and diseased mucosa, which may make these cases good candidates for referral.
Important considerations in foreign-body cases include the:
- Location of the material in the GI tract.
- Type of foreign body encountered.
- Clinical signs associated with the foreign body.
Objects in the esophagus are excellent candidates for endoscopic retrieval because esophageal surgery is often difficult or impossible. Likewise, blind removal techniques or attempts to advance foreign bodies into the stomach risk perforating or damaging the esophagus.
These risks are ameliorated by endoscopy, whereby a clinician may visualize and remove the object with the use of a variety of retrieval forceps in a non-invasive and less traumatic manner.
Objects in the stomach may be treated with either endoscopy or surgery. Although surgery is almost always successful, endoscopy may be selected because it is fast and relatively non-invasive. With a few exceptions, swallowed objects residing in the stomach can be pulled back through the esophagus and removed by a endoscopist.
Most ingested objects have features that allow endoscopic retrieval forceps to grasp and hold, but rounded, blunt or friable objects can be challenging and may require the use of endoscopic nets or nooses.
Despite the allure of endoscopy, general surgery may still be preferred in some cases. Certain objects with sharp edges or hooks (e.g. multi-pronged fishing lures) pose a risk to the esophageal and gastric mucosa during endoscopic retrieval.
Surgery is a better choice for most linear foreign bodies. Although it is uncommon, the endoscopist should consider the potential for a gastric foreign body to become lodged in the esophagus during removal. As a general rule, foreign material residing in the small intestine is beyond the reach of the endoscope. <HOME>
Dr. Ryan, Dipl. ACVIM (internal medicine), is an assistant professor of companion animal medicine at the Louisiana State University School of Veterinary Medicine. He previously worked in general practice and in referral specialty practice.