Page 1216 - Clinical Small Animal Internal Medicine

1154 Section 10 Renal and Genitourinary Disease

and quickly stabilize the patient. Typical ureteral stent traditional surgery. Surgical placement with fluoroscopic
VetBooks.ir sizes are 2.5 Fr for cats and 3.7 or 4.7 Fr for dogs. Ureteral guidance has a procedural success rate of more than 95%
in cats and 100% in dogs; with endoscopic and fluoro­
stents have many benefits:
90% in dogs. There are relatively few major long‐ or
● immediate decompression of the renal pelvis scopic guidance, the success rate is 20% in cats and over
passive ureteral dilation for urine and stone passage
● short‐term complications (Table 123.5), and the stents
prevention of strictures and leakage associated with
● are typically left in place long term. In the authors’ (AB)
surgical or nonsurgical procedures
prevention of a ureteral obstruction after ESWL experience to date, the longest duration of stent patency
● in a feline ureter is more than seven years and in dogs
can be easily removed.
●
more than 10 years.
In cases of obstructive pyonephrosis, endoscopic ure­ The risks of stent placement need to be understood,
teral and renal pelvic catheterization can lavage the renal and owners must be educated on these risks before con­
pelvis and ureter of infected debris and a ureteral stent sidering this option (see Table 123.5). The greatest risks
can then be placed to maintain ureteral patency. All of are associated with device placement, as the stent can
these benefits have been clearly documented in human be very difficult to place in some feline patients, and
medicine and, more recently, in veterinary medicine. appropriate training and experience with the procedure
Ureteral stenting in dogs and cats performed by an are critical to its success. Risks seen months to years
experienced operator is associated with a lower morbid­ after stent placement are typically not life threatening,
ity and mortality rate (<2% and 7%, respectively) than and are relatively easy to address on an outpatient basis

Table 123.5 Immediate, short‐term, and long‐term complications of various minimally invasive procedures to manage ureteroliths
in dogs and cats

Complications

Short‐term (1
Procedure Operative Postoperative (<1 week) week–1 month) Long‐term (>1 month)

Feline Ureteral perforation with Fluid overload during postobstructive Dysuria (self‐ Dysuria (38%) nearly all
ureteral guidewire (little clinical diuresis (<5%) limiting 7–14 respond to prednisolone and/
stent consequence) Failure of creatinine to improve (<5%) days) or prazosin
Leakage if concurrent MORTALITY (<8%) typically due to Inappetence UTI (30%; 34% pre‐op)
ureterotomy needed nonurinary causes (pancreatitis or (temporary) Reobstruction (19%)
Eversion of ureteral mucosa congestive heart failure) – Stricture recurrence (54%)
during stent passage – Adhesions around ureter
Ureteral tear during stent (23%)
passage Obstructive pyelonephritis
(8%)
Chronic hematuria (18%)
Stent migration (6%)
Ureteral reflux (1%)
Canine Endoscopic failure (~3%) MORTALITY (<1%) Dysuria (<1%) Proliferative tissue at
ureteral Ureteral perforation (<1%) ureterovesicular junction
stent Leakage (<1%) (25%)
Ureteral tear (<1%) UTIs (~10%; >60% pre‐op)
Migration (<5%)
Occlusion (<5%)
Dysuria (<3%)
SUB Renal pelvis penetration by Leakage (5%) Dysuria (<2%) UTI (15%; 35% pre‐op)
guidewire (<5%) Fluid overload (<5%) Inappetence Blockage of system (9%)
Kinking of catheters (~5%) Failure of creatinine to improve (<5%) (temporary) (stones 8%, purulent material
Inability to place SUB Blockage of system (3%) 1%)
device (<1%) (blood clot, purulent material, device Dysuria (<2%)
failure)
MORTALITY 5.6%
Source: Reproduced with permission from Defarges A, Berent AC, Dunn M. New alternatives for minimally invasive management of uroliths:
ureteroliths. Compend Contin Educ Vet 2013; 35(3): E1–E7.
SUB, subcutaneous ureteral bypass; UTI, urinary tract infection.