Retrograde catheterization of the urinary bladder is a common, straightforward, and essential procedure in the management of many disorders of the urinary tract in most animal species. The procedure is used to obtain urine samples for analysis, allow decompression of the bladder, and facilitate contrast imaging of the lower urinary tract. Urinary catheterization is of particular importance in male small ruminants for determining the patency of the urethra and during attempts to dislodge obstructing uroliths.
Urinary bladder catheterization in male artiodactyl species is considered impossible with conventional straight-tipped catheters because of the presence of a urethral recess.1 In small ruminants, this recess is located within the caudal portion of the urethral wall at the level of the ischiatic arch and is approximately 0.5 cm deep.2 Ultrasmall-diameter endoscopes (outer diameter, 2.5 to 2.8 mm) can be used to visually examine the junction of the urethral recess and the more proximal urethra. A guidewire can be passed via the endoscope into the proximal portion of the urethra and urinary bladder, then the scope is withdrawn and a catheter is placed over the wire into the proximal portion of the urethra and bladder. Many endoscopes of sufficiently small size are not long enough to reach the urethral recess. Such small-diameter, longer endoscopes (nephropyeloscopes) are expensive, fragile, and not conducive to use in large animal veterinary practice. Also, a guidewire that is more than twice the length of the endoscope is required to complete the procedure.
Alternatively, a curved tipped catheter can be used to bypass the urethral recess. Thus far, reports on such use in ruminants have been limited to a single report3 of urinary bladder catheterization. In that report, a human femoral angiography catheter with a curved tip was successfully passed into the urinary bladder of a healthy goat, a healthy calf, and 3 dysuric goats; however, all catheters were passed under fluoroscopic guidance. Although that reported study3 was limited in scope, it provided evidence that it is possible to pass a urinary catheter into the urinary bladder of a goat in a retrograde direction by use of a catheter with a curved tip.
In the authors’ clinical experience with using various human angiographic catheters in small ruminants, some tip configurations can be passed without fluoroscopic guidance and successfully bypass the urethral recess with minimal manipulation, whereas other catheters are less useful for this purpose. Additionally, some of the catheters used by the authors in the past would be considered cost-prohibitive for routine use. After discovering some moderate-length angiographic catheters that were fairly economical, we chose to evaluate various catheter designs for their suitability for a blind approach to cystic catheterization in male goats.
The purpose of the study reported here was to identify and evaluate 3 types of angiographic catheters for retrograde urinary bladder catheterization in healthy male goats. The selected catheters differed in severity of the angle and length of curvature of the tip. We hypothesized that it would be impossible to blindly pass a straight catheter into the urinary bladder and possible to blindly pass 2 other types of curved-tip angiographic catheters retrograde up the urethra and into the urinary bladder of male goats. The primary objective was to determine whether an angiographic catheter could be blindly used for retrograde catheterization of the urinary bladder in male goats. Additional objectives were to assess whether one type of catheter could be passed more readily than the others and whether clinical experience would have an impact on the success of urinary bladder catheterization.
Supported by the Research Advisory Committee at Oklahoma State University.
Imager II 5F selective catheter GEN (1.70 mm), Boston Scientific, Marlborough, Mass.
Imager II 5F selective catheter Bern (1.70 mm), Boston Scientific, Marlborough, Mass.
Imager II 5F selective catheter H1 (1.70 mm), Boston Scientific, Marlborough, Mass.
Surgilube, Savage Laboratories, Fougera Pharmaceuticals Inc, Melville, NY.
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