The most common ureteral conditions include: ureteroliths, ureteral trauma, congenital anomalies (e.g., ectopic ureters), ureterocele, and ureterovaginal fistula
Ureteroliths generally result from distal migration of nephroliths; these may be clinically silent, cause nonspecific signs (e.g., lethargy, weight loss), or cause signs of obstruction or acute kidney injury
Ureteral obstruction can result from cellular debris, blood clots, ureteroliths, strictures, or extraluminal compression
Ureteroliths are the most common cause of ureteral obstruction in cats
Ureteral trauma can be associated with blunt abdominal trauma, penetrating wounds, or accidental ligation/transection during ovariohysterectomy
Congenital ureteral anomalies include circumcaval ureter, ectopic ureter, and ureterocele
Ureterovaginal fistula may be congenital or iatrogenic due to inadvertent ligation of the ureter along with the vaginal stump during ovariohysterectomy
Clinical signs may be absent, especially if ureteral disease is unilateral and the contralateral kidney is healthy
When present, signs can include recurrent lower urinary tract infection, incontinence, anorexia, weight loss, abdominal pain, and/or vomiting
Physical exam findings are variable and will depend on the underlying disease; may include palpable renomegaly (due to hydronephrosis) or renal asymmetry, abdominal pain, depression, or findings consistent with acute kidney injury (e.g., bradycardia, dehydration, hypothermia, and tachypnea)
Routine diagnostic workup should include urinalysis, urine culture, complete blood count, and biochemistry panel to assess systemic health and identify concurrent illness
Survey radiography and abdominal ultrasound can often identify ureteroliths and ureteral obstruction; advanced imaging may be required to identify ectopic ureter, fistula, or ureterocele
In dogs, struvite ureteroliths may respond to dietary or medical dissolution; however, concurrent ureteral stenting is required
50% to 60% of ureteroliths in dogs and > 90% of ureteroliths in cats are calcium oxalate and therefore will not respond to dissolution therapy
Medical expulsive therapy for ureteroliths (including obstructive ureteroliths) can be attempted; however, the success rate is relatively low
Surgical options include ureteral stenting, subcutaneous ureteral bypass, laser ablation, and conventional surgery (e.g., ureterotomy)
Extracorporeal shock wave lithotripsy is a non-invasive option for canine ureteroliths (depending in part on the size of the ureterolith)
Prognosis varies with underlying cause
Postoperative complications following surgical management of ureteral obstruction include re-blocking, stricture formation, urine leakage, and urinary tract infection
Depending in part on the surgical procedure performed to correct ectopic ureters, 45% to 75% of patients may continue to have episodes of incontinence and may require long-term medical management (e.g., phenylpropanolamine)
Causes and Risk Factors
Causes
Ureteroliths
Ureteral trauma (e.g., secondary to penetrating wound, or blunt abdominal trauma)
Congenital anomaly
Ectopic ureter
Ureterocele
Congenital ureteral orifice stenosis
Circumcaval ureter
Iatrogenic (e.g., accidental ligation or transection of ureter during ovariohysterectomy)
Neoplasia
Primary ureteral neoplasia is rare; however, metastatic neoplasia can affect the ureters
Risk Factors
Previous history of ureteroliths is a risk factor for recurrence
Urinary tract infections can increase the risk of infection-induced struvite ureteroliths in dogs
Signalment
Will depend on the ureteral disorder
Ureteral trauma can occur in dogs or cats of any age
Ureteroliths can occur in dogs or cats of any age; however, diagnosis typically occurs in middle age to older patients as these can be clinically silent for extended periods of time
Ectopic ureter is more commonly diagnosed in young female dogs; less common in male dogs and cats
Although dogs of any breed can have congenital ectopic ureters, some breeds appear predisposed:
The most common ureteral conditions include ureteroliths, ureteral trauma, congenital anomalies (e.g., ectopic ureters), ureterocele, and ureterovaginal fistula
Ureteroliths generally result from distal migration of nephroliths; these may be clinically silent, cause nonspecific signs (e.g., lethargy, weight loss), or cause signs of obstruction or acute kidney injury
Ureteral obstruction can result from cellular debris, blood clots, ureteroliths, strictures, or extraluminal compression
The narrow diameter of the ureter means even small amounts of cellular debris or small ureteroliths can result in obstruction
Extraluminal compression may also result in obstruction (e.g., neoplasia, circumcaval ureter)
Ureteroliths are the most common cause of ureteral obstruction in cats
Ureteral trauma can be associated with blunt abdominal trauma, penetrating wounds, or accidental ligation/transection during ovariohysterectomy
Congenital ureteral anomalies include:
Circumcaval ureter
A congenital displacement of the vena cava leads to extraluminal ureteral compression
Clinical signs, when present, are associated with ureteral compression or obstruction
Ectopic ureter
Defined as ureteral openings distal to the trigone
May be unilateral or bilateral
Urinary incontinence is the most common clinical sign
Ureterocele
Defined as a cystic dilation of the distal ureter where it meets the bladder
Urinary incontinence is a common clinical sign
Commonly seen in patients with ectopic ureter
Dysuria and recurrent urinary tract infections are common clinical signs
Ureterovaginal fistula may be congenital or iatrogenic due to inadvertent ligation of the ureter along with the vaginal stump during ovariohysterectomy; urinary incontinence is common
Clinical signs may be absent, especially if ureteral disease is unilateral and the contralateral kidney is healthy
Ureteral obstruction may cause acute kidney injury/failure, with associated disease signs. Urinary tract infection, dysuria, stranguria, pollakiuria, abdominal pain, and urinary incontinence are also possible disease signs
Some disease signs are nonspecific (anorexia, weight loss, lethargy, vomiting)
Clinical signs must be differentiated from polyuria, lower urinary tract disease, urine marking, and other causes of urinary incontinence or dysuria
Physical exam findings can vary, depending on underlying disease. Findings may include palpable renomegaly due to hydronephrosis or renal asymmetry, abdominal pain, depression, or findings consistent with oliguric renal failure (e.g., seizures, bradycardia, dehydration, hypothermia, and tachypnea)
Routine diagnostic workup should include urinalysis, urine culture, complete blood count, and biochemistry panel to assess the health of the urinary tract and help rule out other differentials
Survey radiography and abdominal ultrasound can identify ureteroliths and ureteral obstruction in most cases
Advanced imaging may also considered; however, does not necessarily provide more clinical information than the combination of survey radiography and ultrasound
Advanced diagnostic modalities include excretory urography, antegrade pyelography, computed tomography, ureteroscopy, and urethrocystoscopy
Clinical signs will depend on the type of ureteral disease present
Ureteroliths may be clinically silent; signs are most often noted once obstruction is present:
Vomiting
Anorexia
Lethargy
Weight loss
Abdominal pain
Hematuria
Urinary incontinence
Complete, bilateral ureteral obstruction (or unilateral obstruction concurrent with contralateral renal impairment) may present with signs of acute kidney injury
Can identify radiopaque nephroliths and ureteroliths
Ureteroliths smaller than 2 mm are difficult to detect radiographically
Other causes of ureteral obstruction, such as blood clots or cellular debris, are difficult to detect radiographically
In ureteral rupture or trauma, abdominal fluid (uroabdomen, peritonitis) or fluid/urine in the retroperitoneal space may be appreciated as a loss of detail
Nephritis or ureteritis may cause reduced abdominal detail
Renomegaly or renal asymmetry (due to hydronephrosis) may be observed with ureteral obstruction
Recommended in all cases of suspected ureteral obstruction
Ureteral obstruction can be effectively diagnosed based on identification of hydronephrosis and hydroureter (proximal to an obstructive lesion)
Normal ureters should not be discernable via ultrasound
Can be useful in identifying ureteroliths, peri-renal effusion, masses, hydroureter, ectopic ureters, or ureteroceles; however, other imaging modalities may be more sensitive and specific for some conditions (e.g., ectopic ureters)
Helpful for identifying radiolucent ureteroliths, or those too small to detect via survey radiography
Abdominal fluid (urine) in the retroperitoneal space may be identified in ureteral trauma or rupture
Can also be useful for ruling out other causes for the clinical signs such as bladder calculi or neoplasia
Contrast-enhanced CT is reliable for diagnosing ureteral strictures and compressions, ureteroliths, neoplasia, ectopic ureters, ureteroceles, and assessing the urogenital tract for concurrent anomalies
Under ultrasound guidance, contrast agent is injected into the renal pelvis; fluoroscopy or serial radiography is used to track movement of the contrast agent into the bladder
Facilitates identification of ureteral obstructions, filling defects, and renal pelvic abnormalities
Can be performed during interventional procedures such as placement of ureteral stents or subcutaneous bypass device
Potential complications include leakage of contrast agent, renal pelvic laceration, and focal hemorrhage
Facilitates visualization of the bladder, ureteral orifice, urethra, and vaginal vestibule
Ureteroscopy is limited in small pets, due to the narrow diameter of the ureters
Urethrocystoscopy with abdominal radiography and ultrasound has largely replaced excretory urography as the preferred diagnostic method for identifying ectopic ureter; also facilitates minimally-invasive surgical correction (laser ablation) at the time of diagnosis
Combining cystoscopy with abdominal ultrasound facilitates a more complete study of the upper and lower urinary tract
In male dogs, visibility is more limited than in female dogs; CT and excretory urography may be better options for diagnosing ectopic ureters in male dogs
Infection-induced struvite ureteroliths can be prevented by earlier diagnosis and treatment of urinary tract infections; therapeutic diets also have a role in struvite urolith prevention
One study (Level 3) identified dog breeds at increased risk for calcium oxalate urolithiasis and recommended screening these dogs beginning at 5 to 6 years of age, to facilitate earlier diagnosis and intervention; these breeds include:
Bichon frise
Brussels Griffon
Cairn terrier
Chihuahua
Jack Russell terrier
Japanese Chin
Lhasa apso
Maltese
Miniature pinscher
Miniature schnauzer
Pomeranian
Yorkshire terrier
Dogs diagnosed with ectopic ureters or other congenital ureteral disease should be removed from breeding programs
Treatment
General Points
Definitive treatment will depend on the underlying cause
Asymptomatic pets with non-obstructive ureteroliths (i.e., no hydronephrosis or ureteral dilation) can be serially monitored using abdominal ultrasound and bloodwork
50% to 60% of ureteroliths in dogs and > 90% of ureteroliths in cats are calcium oxalate
Medical dissolution of ureteroliths can be considered for dogs but is not recommended unless a stent is placed to reduce the risk of obstruction; medical dissolution is not recommended for cats
Medical expulsive therapy with intravenous fluids, alpha adrenergic antagonists, and diuretics can be considered for patients with ureteroliths; however, monitoring of electrolyte and renal values every 6 to 12 hours is required
Pets with ureteral obstruction should be managed as an emergency, whether obstruction is partial or complete
Persistent obstruction can result in permanent renal damage
Some pets with ureteral obstruction, especially bilateral obstruction, can be critically ill due to acute kidney injury at the time of diagnosis; requires emergent stabilization and intensive care, as well as relief of the obstruction
The goal of MET is for the ureterolith to move distally into the bladder, and eventually pass during voiding
MET involves the use of intravenous fluid therapy, diuretics (e.g., mannitol, furosemide), and prazosin (alpha-adrenergic antagonist to promote relaxation and reduce ureteral spasm), amitriptyline, and analgesic therapy
Can be considered in the absence of infection, and if renal function is adequate
Should only be considered in well hydrated patients
Serial ultrasonography or radiography is necessary to assess movement of the ureterolith; progressive enlargement of the renal pelvis or ureter should prompt alternate intervention
Patients should be monitored for sepsis, oliguria, worsening azotemia, hyperkalemia, or urinary tract infection; blood pressure and renal and electrolyte levels should be evaluated every 6 to 12 hours
In dogs and cats, MET can be attempted for 24 to 72 hours; if the ureterolith has not moved distally within this time frame, other treatment should be considered
MET is often not successful in cats due to the presence of concurrent ureteral stricture
Stenting, placement of a subcutaneous ureteral bypass (SUB) device, or traditional surgical decompression should be performed promptly if MET is unsuccessful
Intravenous crystalloid fluid therapy
Dogs and cats: 80 to 120 mL/kg/day, depending on patient's cardiovascular status
Alpha-adrenergic antagonist
Prazosin
Dogs: 0.5 mg/kg PO every 12 hours
Cats: 0.25 to 0.5 mg/cat PO every 12 to 24 hours
Should be given on an empty stomach
Tamsulosin
Dogs: 0.1 mg/10 kg body weight PO every 24 hours
Alternate dose: 0.4 mg/dog PO every 24 hours
Cats: 0.004 to 0.006 mg/kg PO every 12 to 24 hours
May take up to 3 days for effects to occur
Should be given on an empty stomach
Diuretic therapy
Furosemide 1 to 2 mg/kg IV as an initial bolus, then 0.5 to 1 mg/kg/hour as a continuous rate infusion
Mannitol 0.25 to 0.5 g/kg slowly IV over 10 to 20 minutes, then 60 to 120 mg/kg/hr as a continuous rate infusion
Tricyclic antidepressant
Amitriptyline
Cats: 0.5 to 2 mg/kg PO every 24 hours
Dogs: 1 to 2 mg/kg PO every 12 hours
Surgical Interventions
Available surgical procedures are all associated with similar potential peri- and postoperative complications, including urine leakage, ureteral inflammation, stricture, infection, and re-obstruction (in the case of ureteral obstruction)
The decision about which surgical procedure to choose may be based on factors such as patient condition, the nature of the disease, and surgeon preference
Minimally invasive options may offer benefits such as reduced postoperative morbidity and hospitalization
Stenting or subcutaneous ureteral bypass is the preferred surgical option for cats with obstructive ureteroliths
Stenting is the preferred surgical method in dogs with obstructive ureteroliths; can be combined with shock wave lithotripsy
Referral to a veterinary specialty center is recommended for advanced treatment modalities; early intervention will improve successful maintenance of renal function
Laser ablation
Minimally invasive option for correcting ectopic ureter; can also be considered for correction of ureteroceles or ureteral orifice stenosis
Following surgical correction of ectopic ureter, an estimated 30% to 75% of patients continue experiencing some urinary incontinence and may benefit from medical management, or placement of a hydraulic urethral occluder
Ureteral stent placement
For obstructive ureteroliths, ureteral blockages, or strictures; diverts urine around the obstruction and through the stent
May be left in place or removed when the obstruction has resolved (e.g., following medical dissolution of a struvite ureterolith)
Can be used to divert urine around a ureteral neoplasm
Can be performed as sole treatment, or in conjunction with medical/dietary dissolution of struvite, cystine, or urate ureteroliths in dogs
In dogs with calcium oxalate ureteroliths, stent placement can be performed alone, or combined with shock wave lithotripsy
Can be performed cystoscopically with fluoroscopy or via traditional surgery
For cats with ureteral obstruction and concurrent urinary tract infection, stenting may be preferable to subcutaneous ureteral bypass
In a study of cats with ureteral obstruction (Level 2), azotemia was more likely to be resolved prior to hospital discharge for cats undergoing stenting, compared with cats undergoing ureterotomy
Potential perioperative complications include ureteral tearing/perforation, and stent migration
Postoperative complications include re-obstruction, stent migration, hematuria, and urinary tract infection
Placement of a subcutaneous ureteral bypass (SUB) device
Placement of a SUB device may be considered for patients with obstructive ureteroliths, ureteral strictures, ureterolith that has failed medical therapy, ureteral neoplasia, or rupture
Can be performed cystoscopically, or via traditional approach
Has been associated with better survival rates in cats, compared with traditional ureterotomy
Potential postoperative complications include kinking of tubing, device leakage, and occlusion with blood clots
Potential long-term complications include device mineralization and re-obstruction
Ureterotomy
Consider for obstructive ureteroliths
Associated with greater postoperative complications and higher mortality rates compared with stent placement, SUB, or shock-wave lithotripsy
Complications include stricture formation, infection, and reobstruction
Ureteroneocystostomy or Neoureterocystostomy
For obstructive ureteroliths, distal ureteral rupture, ectopic ureter
Involves transection of the ureter, followed by re-implantation into the bladder
When used to treat ureteroliths, this procedure is associated with greater postoperative complications and higher mortality rates compared with stent placement, SUB, or shock-wave lithotripsy
Ureteronephrectomy or Nephroureterectomy
Surgical resection of ureter and associated kidney
Can be used to address ureteral neoplasia and/or rupture, as long as disease is unilateral and the contralateral kidney is functioning adequately
Other Therapies
Extracorporeal shock wave lithotripsy (ESWL)
Noninvasive option for management of ureteroliths in dogs
Not recommended for stones > 1.5 cm in diameter
Not recommended for cats, due to smaller ureteral diameter
Using fluoroscopic guidance, external shock waves are used to fragment the ureterolith, facilitating passage of the fragments
Multiple treatments may be required to achieve adequate fragmentation
Placement of a ureteral stent is not required, but may facilitate passage of fragments, reducing risk of obstruction
Hemodialysis
Limited availability except in a referral setting
May be beneficial for patients with ureteral obstruction and severe azotemia prior to surgical intervention
Follow-up
General Points
In cases of ureteral obstruction and uroliths, clients should be counseled about the risk of recurrence following surgical or medical intervention
Following surgical correction for ectopic ureters, owners should be advised that surgical correction is not always completely curative, and medical management may be required postoperatively
Therapeutic Follow-up
Following treatment for ureteroliths, radiographs, ultrasound, biochemistry panel, and urinalysis/culture should be repeated every few months; depending on severity of initial illness, repeat diagnostics every 3 months for the first year, and then every 6 months thereafter
Ultrasound or fluoroscopy can be used postoperatively, following placement of a ureteral stent or subcutaneous ureteral bypass device, to re-assess renal pelvic dilation following relief of ureteral obstruction
Prognosis
Prognosis varies with underlying cause:
Complete, bilateral ureteral obstruction can be fatal within 2 to 5 days
Postoperative complications following surgical management of ureteral obstruction include re-blocking, stricture formation, urine leakage, and urinary tract infection
Owners should be counseled that risk of urinary tract infection and repeat obstruction warrant long-term monitoring
Ectopic ureters: depending in part on the surgical procedure performed, 45% to 75% of patients may continue to have episodes of incontinence and may require medical management (e.g., phenylpropanolamine) following surgery
Pets with ureteroliths have a high risk for recurrence
Evidence
Guidelines and Consensus Statements
Lulich JP, Berent AC, Adams LG, et al. ACVIM small animal consensus recommendations on the treatment and prevention of uroliths in dogs and cats. J Vet Intern Med. 2016 Sep;30(5):1564-74. Level BArticle
Systematic Reviews/Meta-analyses
None available
Randomized, Controlled Trials (RCTs)
None available
Other Studies or Reviews
Culp WT, Palm CA, Hsueh C, et al. Outcome in cats with benign ureteral obstructions treated by means of ureteral stenting versus ureterotomy. J Am Vet Med Assoc. 2016 Dec 1;249(11):1292-1300. Level 2Abstract
Lonc KM, Kaneene JB, Carneiro PAM, et al. Retrospective analysis of diagnoses and outcomes of 45 cats with micturition disorders presenting as urinary incontinence. J Vet Intern Med. 2020;34(1):216-26. Level 3
Kulendra NJ, Borgeat K, Syme H, et al. Survival and complications in cats treated with subcutaneous ureteral bypass. J Small Anim Pract. 2020 Sep 14. doi: 10.1111/jsap.13226. Epub ahead of print. PMID: 32926426. Level 3
Pennington CE, Halfacree Z, Colville-Hyde C, et al. Factors associated with positive urine cultures in cats with subcutaneous ureteral bypass system implantation. J Feline Med Surg. 2020 Aug 25:1098612X20950312. doi: 10.1177/1098612X20950312. Epub ahead of print. PMID: 32840421. Level 3
Plater BL, Lipscomb VJ. Treatment and outcomes of ureter injuries due to ovariohysterectomy complications in cats and dogs. J Small Anim Pract. 2020 Mar;61(3):170-6. Level 3
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Acierno MJ, Labato MA. Canine incontinence. Vet Clin North Am Small Anim Pract. 2019;49(2):125-40. Level 3
Owen LJ. Ureteral ectopia and urethral sphincter mechanism incompetence: an update on diagnosis and management options. J Small Anim Pract. 2019;60(1):3-17. Level 3
Hunprasit V, Schreiner PJ, Bender JB, et al. Epidemiologic evaluation of calcium oxalate urolithiasis in dogs in the United States: 2010-2015. J Vet Intern Med. 2019 Sep;33(5):2090-5. Level 3 [IND]
Balsa IM, Culp WTN, Palm CA, et al. Factors associated with postobstructive diuresis following decompressive surgery with placement of ureteral stents or subcutaneous ureteral bypass systems for treatment of ureteral obstruction in cats: 37 cases (2010-2014). J Am Vet Med Assoc. 2019 Apr 15;254(8):944-52. Level 3
Etedali NM, Reetz JA, Foster JD. Complications and clinical utility of ultrasonographically guided pyelocentesis and antegrade pyelography in cats and dogs: 49 cases (2007-2015). J Am Vet Med Assoc. 2019 Apr 1;254(7):826-34. Level 3
Milligan M, Berent AC. Medical and interventional management of upper urinary tract uroliths. Vet Clin North Am Small Anim Pract. 2019 Mar;49(2):157-74. Level 3
Rogatko CP, Berent AC, Adams LG, et al. Endoscopic laser-ablation for the treatment of orthotopic and ectopic ureteroceles in dogs: 13 cases (2008-2017). J Vet Intern Med. 2019 Mar;33(2):670-9. Level 3
Wormser C, Reetz JA, Drobatz KJ, et al. Diagnostic utility of ultrasonography for detection of the cause and location of ureteral obstruction in cats: 71 cases (2010-2016). J Am Vet Med Assoc. 2019 Mar 15;254(6):710-5. Level 3
Kopecny L, Palm CA, Drobatz KJ, et al. Risk factors for positive urine cultures in cats with subcutaneous ureteral bypass and ureteral stents (2010-2016). J Vet Intern Med. 2019 Jan;33(1):178-83. Level 3
Berent AC, Weisse CW, Bagley DH, et al. Use of a subcutaneous ureteral bypass device for treatment of benign ureteral obstruction in cats: 174 ureters in 134 cats (2009-2015). J Am Vet Med Assoc. 2018 Nov 15;253(10):1309-27. Level 3
Fages J, Dunn M, Specchi S, et al. Ultrasound evaluation of the renal pelvis in cats with ureteral obstruction treated with a subcutaneous ureteral bypass: a retrospective study of 27 cases (2010-2015). J Feline Med Surg. 2018 Oct;20(10):875-83. Level 3
Nesser VE, Reetz JA, Clarke DL, et al. Radiographic distribution of ureteral stones in 78 cats. Vet Surg. 2018 Oct;47(7):895-901. Level 3
Gallagher A. Interventional radiology and interventional endoscopy in treatment of nephroureteral disease in the dog and cat. Vet Clin North Am Small Anim Pract. 2018 Sep;48(5):843-62. Level 3
Meler E, Berent AC, Weisse C, et al. Treatment of congenital distal ureteral orifice stenosis by endoscopic laser ablation in dogs: 16 cases (2010-2014). J Am Vet Med Assoc. 2018 Aug 15;253(4):452-62. Level 3
Clarke DL. Feline ureteral obstructions Part 2: surgical management. J Small Anim Pract. 2018 Jul;59(7):385-97. Level 3
Clarke DL. Feline ureteral obstructions Part 1: medical management. J Small Anim Pract. 2018 Jun;59(6):324-33. Level 3
Pavia PR, Berent AC, Weisse CW, et al. Outcome of ureteral stent placement for treatment of benign ureteral obstruction in dogs: 44 cases (2010-2013). J Am Vet Med Assoc. 2018 Mar 15;252(6):721-31. Level 3
Lamb CR, Cortellini S, Halfacree Z. Ultrasonography in the diagnosis and management of cats with ureteral obstruction. J Feline Med Surg. 2018 Jan;20(1):15-22. Level 3
Adams LG. Ureteral disorders. In: Ettinger SJ, Feldman EC, Cote E, ed.'s. Textbook of Veterinary Internal Medicine: Diseases of the Dog and Cat. 8th ed. St. Louis: Elsevier;2017:1985-91. Level 3
Livet V, Pillard P, Goy-Thollot I, et al. Placement of subcutaneous ureteral bypasses without fluoroscopic guidance in cats with ureteral obstruction: 19 cases (2014-2016). J Feline Med Surg. 2017 Oct;19(10):1030-9. Level 3
Noël SM, Claeys S, Hamaide AJ. Surgical management of ectopic ureters in dogs: Clinical outcome and prognostic factors for long-term continence. Vet Surg. 2017;46(5):631-41. Level 3
Papich MG. Saunders Handbook of Veterinary Drugs: Small and Large Animal, 4th Edition. St Louis, MO: Elsevier; 2016. Level 3
Palm CA, Culp WT. Nephroureteral obstructions: the use of stents and ureteral bypass systems for renal decompression. Vet Clin North Am Small Anim Pract. 2016 Nov;46(6):1183-92. Level 3
Berent AC. Interventional radiology of the urinary tract. Vet Clin North Am Small Anim Pract. 2016 May;46(3):567-96. Level 3
Wormser C, Clarke DL, Aronson LR. Outcomes of ureteral surgery and ureteral stenting in cats: 117 cases (2006-2014). J Am Vet Med Assoc. 2016 Mar 1;248(5):518-25. Level 3
Steinhaus J, Berent AC, Weisse et al. Clinical presentation and outcome of cats with circumcaval ureters associated with a ureteral obstruction. J Vet Intern Med. 2015 Jan;29(1):63-70. Level 3
Berent A, Weisse C. Interventional strategies for urinary disease. In: Bonagura JD, Twedt D, ed.'s. Kirk's Current Veterinary Therapy XV. Philadelphia:Elsevier Saunders;2014:884-92. Level 3
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Additional Reading
Milligan ML, Berent AC, Weisse CW, et al. Outcome of SUB placement for the treatment of benign ureteral obstruction in dogs: nine dogs and 12 renal units (2013 to 2017). J Small Anim Pract. 2020 Jul;61(7):428-35.
Oh H, Kim S, Kim S, et al. Evaluation of the ureteral jet in dogs by using color Doppler ultrasonography. J Vet Sci. 2017 Sep 30;18(3):399-406.
Secrest S, Bugbee A, Waller K, et al. Comparison of transverse computed tomographic excretory urography images and maximum intensity projection images for diagnosing ectopic ureters in dogs. Vet Radiol Ultrasound. 2017 Mar;58(2):163-8.