7 steps to perform retrograde urohydropropulsion
Mar 01, 2009
EDITOR' NOTE: Last month, in the first of two articles, retrograde urohydropropulsion was discussed as a technique for restoring urethral patency in dogs, usually with less chance of iatrogenic trauma. This second article describes seven steps for performing retrograde urohydropropulsion.
Step 1: Verification and localization of urethroliths
Perform appropriate diagnostic procedures to localize the sites of urethrolith(s). Evaluate their number, size, radiodensity and surface characteristics. Since uroliths rarely form in the urethra but migrate from the bladder lumen into the urethra, be sure to include the urinary bladder in the evaluation. Palpation of the posterior urethra (including palpation of the urethra per rectum) followed by appropriate survey or contrast radio-graphy should be performed to establish the site(s) and cause(s) of outflow obstruction.
Step 2: Decompressive cystocentesis
Some benefits of this are:
1) An uncontaminated representative urine sample suitable for analysis and culture is obtained.
2) Temporarily correcting the problem by decompressive cystocentesis provides a mechanism to ameliorate discomfort and adverse effects associated with post-renal azotemia.
3) Decompression of an over-distended urinary bladder and proximal urethra may decrease resistance to retrograde hydropropulsion of urethroliths back into the bladder lumen. Failure to decompress before the procedure can result in impaired ability to flush urethroliths into the urinary bladder (Table 1, p. 8S).
If excessive pressure is created in the over-distended bladder lumen, it will rupture. The potential risks of performing decompressive cystocentesis are that (a) it may result in extravasation of urine into the bladder wall and/or peritoneal cavity, and (b) it may injure the bladder wall or surrounding structures.
Although these complications could be severe in patients with a devitalized bladder wall, in our experience this has been a very uncommon exception rather than the rule, provided that the majority, but not all, of the urine is removed from the bladder before initiating urohydopropulsion.
Intra-peritoneal escape of a small quantity of urine through the pathway created by a 22-gauge hypodermic needle usually is of little consequence. The potential of trauma to the bladder and adjacent structures can be minimized by proper technique.