A ureteral obstruction is a serious clinical problem in dogs and cats and can occur secondary to ureterolithiasis, neoplasia, ureteral stricture or stenosis, iatrogenic ureteral ligation, and postsurgical trauma or edema.1–9 Hydronephrosis typically occurs following ureteral obstruction and can result in increased intrarenal hydrostatic pressure, decreased ipsilateral kidney function,10–13 and potentially life-threatening azotemia, particularly when contralateral renal function is impaired. In cases of partial ureteral obstruction, some patients can be managed medically with supportive care until a ureterolith passes,1,8 whereas others may require more aggressive management for stabilization. The use of a nephrostomy catheter may aid in stabilization and help to avoid permanent renal damage prior to a more prolonged anesthetic procedure for definitive treatment.2,4,14 If medical management of a ureteral obstruction fails, decompression of the renal pelvis becomes imperative to preserve renal function ipsilaterally until definitive treatment is provided.
The physiologic response to a ureteral obstruction is complex. Studies in clinically normal dogs have shown that ureteral pressures increase immediately following obstruction.10 This increase in pressure due to ureteral obstruction is transmitted to the entire nephron, and a decrease in glomerular filtration rate subsequently occurs.15 The contralateral kidney will have an increase in its glomerular filtration rate in response if there is renal reserve for a compensatory hypertrophic mechanism. This may not be the case in patients with preexisting chronic kidney disease, seen in > 50% of dogs and 83% of cats with calculi-induced ureteral obstructions.1,7 The longer the ureter remains obstructed, the greater the potential for progressive irreversible damage. In experimentally induced ureteral obstruction in dogs, it has been found that after 7 and 14 days of complete ureteral obstruction, the glomerular filtration rate is permanently diminished by 35% and 54%, respectively.10–13,15,16
Traditional methods of renal pelvis decompression include various surgical options (ureterotomy, ureteral reimplantation, and ureteronephrectomy), depending on the cause and location of the ureteral obstruction.2,7,8 For severely debilitated patients in which more prolonged surgical procedures should be avoided, hemodialysis and nephrostomy catheter placement are often quicker alternatives to traditional definitive surgical correction. Advantages of a nephrostomy catheter placement, compared with intermittent hemodialysis or surgical correction, include commercial availability of the catheter, minimization of anesthesia-associated patient morbidity, ability to provide rapid renal pelvic decompression, assess ipsilateral urine production and ureteral patency, and determine whether adequate renal function ultimately remains, thus giving justification for a more definitive subsequent ureteral intervention.7–20,a Nephrostomy catheters may also potentially be helpful following intervention as a surgical site is healing (after ureterotomy) or in patients awaiting transfer to facilities capable of providing a more definitive procedure.
There is a paucity of literature on the use of nephrostomy catheters in clinical veterinary patients,2,8,19–23,b and to the authors’ knowledge, no case series exists describing technique or outcome in small animal medicine. One report21 describes the case of a feline patient that had 5F red rubber catheters placed for treatment of bilateral ureteral ligations during ovariohysterectomy. One of the catheters dislodged within 10 hours after placement, and the other became obstructed. In a retrospective study2 of ureteral obstructions in cats, the highest morbidity rate occurred in patients with nephrostomy catheters where urine leakage was a common complication. Complications related to nephrostomy catheters were seen in 46% of patients and included urine leakage, poor drainage, and catheter dislodgement. To the authors’ knowledge, all other reports8,20 are review articles that describe placement of a Foley catheter, red rubber catheter, or a large (15 to 18F) fenestrated latex catheter across both poles of the kidney for drainage. Complications, including urine leakage, dislodgement, infection, and hemorrhage, are frequently reported when such catheters are used.2,8
In human urology, percutaneous placement of nephrostomy catheters was first described in 1955.24 Since that time, the type of catheter considered standard of care, the safest, and most effective is the locking-loop PNC.24–26 In people, these catheters can be left in place long term, provided careful maintenance and routine catheter exchanges are performed. The overall major and minor complication rates associated with PNCs in people are 3% to 8% and 3% to 25%, respectively, with complications including hematuria, infection, dislodgement, pneumothorax or hemothorax, intestinal injury, septicemia, and urine leakage.26,27 The purpose of the study reported here was to describe the clinical use and outcome of PNC placement in dogs and cats for various problems and to describe the technique of placing a locking-loop PNC by either a percutaneous approach or via a ventral midline laparotomy
Congestive heart failure
Pigtail nephrostomy catheter
Transitional cell carcinoma
Berent A, Weisse C, Bagley D, et al. The use of locking-loop nephrostomy catheters for ureteral obstructions in dogs and cats (abstr). Vet Surg 2009;38:E26.
Berent A, Weisse C, Bagley D, et al. Ureteral stenting for feline ureterolithiasis (abstr). J Vet Intern Med 2009;23:688.
Renal access needle, 18 gauge × 15 cm, Cook Medical, Bloomington, Ind.
Omnipaque, Iohexol 240 mg/mL, GE Healthcare, Princeton, NJ.
ISO-C, Fluoroscopy, Seimens, Malvern, Pa.
Weasel Wire 0.018 or 0.035-inch hydrophilic angle-tipped guidewire, Infiniti Medical LLC, Malibu, Calif.
5F Dawson-Meuller locking-loop pigtail catheter, Cook Medical, Bloomington, Ind.
6F locking-loop pigtail catheter, Infiniti Medical LLC, Malibu, Calif.
Berent A, Weisse C, Bade H, et al. The use of a subcutaneous ureteral bypass for the treatment of ureteral obstructions in cats (abstr). J Vet Intern Med 2011;25:1506.
1 Kyles AE, Hardie EM, Wooden BG, et al. Clinical, clinicopathologic, radiographic, and ultrasonographic abnormalities in cats with ureteral calculi: 163 cases (1984-2002). J Am Vet Med Assoc 2005; 226:932–936.
2 Kyles AE, Hardie EM, Wooden BG, et al. Management and outcome of cats with ureteral calculi: 153 cases (1984-2002). J Am Vet Med Assoc 2005; 226:937–944.
3 Berent A, Weisse C, Bagley D, et al. Ureteral stenting for benign and malignant disease in dogs and cats. Vet Surg 2007; 36:E1–E29.
4 Berent AC, Weisse C, Beal MW, et al. Use of indwelling, double-pigtail stents for treatment of malignant ureteral obstruction in dogs: 12 cases (2006-2009). J Am Vet Med Assoc 2011; 238:1017–1025.
7 Snyder DM, Steffery MA, Mehler SJ, et al. Diagnosis and surgical management of ureteral calculi in dogs: 16 cases (1990-2003). N Z Vet J 2004; 53:19–25.
9 McLouglin MA, Bjorling DE. Ureters. In: Slatter D, ed. Textbook of small animal surgery. 3rd ed. Philadelphia: WB Saunders Co, 2003;1619–1628.
10 Wen JG, Frokiaer J, Jorgensen TM, et al. Obstructive nephropathy: an update of the experimental research. Urol Res 1999; 27:29–39.
11 Fink RW, Caradis DT, Chmiel R, et al. Renal impairment and its reversibility following variable periods of complete ureteric obstruction. Aust N Z J Surg 1980; 50:77–83.
13 Vaughan ED Jr, Sweet RE, Gillenwater JY. Unilateral ureteral occlusion: pattern of nephron repair and compensatory response. J Urol 1973; 109:979–982.
14 Langston CE, Cowgill LD, Spano JA. Applications and outcome of hemodialysis in cats: a review of 29 cases. J Vet Intern Med 1997; 11:348–355.
15 Coroneos E, Assouad M, Krishnan B, et al. Urinary obstruction causes irreversible renal failure by inducing chronic tubulointerstitial nephritis. Clin Nephrol 1997; 48:125–128.
17 Block G, Adams LG, Widmer WR, et al. Use of extracorporeal shock wave lithotripsy for treatment of nephrolithiasis and ureterolithiasis in five dogs. J Am Vet Med Assoc 1996; 208:531–536.
18 Adams LG, Senior DF. Electrohydraulic and extracorporeal shock-wave lithotripsy. Vet Clin North Am Small Anim Pract 1999; 29:293–302.
19 Weisse CW, Berent AC, Todd KL, et al. Clinical applications of interventional radiology in veterinary medicine. J Am Vet Med Assoc 2008; 233:1564–1574.
20 Rawlings C, Bjorling D & Christie B. Ureteral surgery. In: Slatter D, ed. Texbook of small animal surgery. 3rd ed. Philadelphia: Saunders, 2003;1614–1615.
21 Nwadike BS, Wilson LP, Stone EA. Use of bilateral temporary nephrostomy catheters for emergency treatment of bilateral ureter transection in a cat. J Am Vet Med Assoc 2000; 217:1862–1865.
22 Chambers JN, Selcer BA, Barsanti JA. Recovery from severe hydroureter and hydronephrosis after ureteral anastomosis in a dog. J Am Vet MedA ssoc 1987; 191:1589–1592.
23 Ehnen SJ, Divers TH, Gillette D, et al. Obstructive nephrolithiasis and ureterolithiasis associated with chronic renal failure in horses: eight cases (1981-1987). J Am Vet Med Assoc 1990; 197:249–253.
26 Dyer RB, Regan JD, Kavanagh PV, et al. Percutaneous nephrostomy with extension of the techniques: step by step. Radiographics 2002; 22:503–525.
28 Ogeer-Gyles J, Mathews K, Weese JS, et al. Evaluation of catheter-associated urinary tract infections and multi-drug-resistant Escherichia coli isolates from the urine of dogs with indwelling urinary catheters. J Am Vet Med Assoc 2006; 229:1584–1590.
29 Sullivan LA, Campbell VL, Onuma SC. Evaluation of open versus closed urine collection systems and development of nosocomial bacteriuria in dogs. J Am Vet Med Assoc 2010; 237:187–190.
30 Smarick SD, Haskins SC, Aldrich J, et al. Incidence of catheter-associated urinary tract infection among dogs in a small animal intensive care unit. J Am Vet Med Assoc 2004; 224:1936–1940.
31 Lennon GM. Double pigtail ureteric stent versus percutaneous nephrostomy: effects on stone transit and ureteric motility. Eur Urol 1997; 31:24–29.