Sample Topic

Feline | Canine

Ureteral Disorders

Summary

  • 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
  • Medical treatment options are limited:
    • Antimicrobials are recommended for ureteroliths (dogs), pyelonephritis, and lower urinary tract infection
    • 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:
    • Border terriers
    • Briards
    • English bulldogs
    • Fox terriers
    • Griffons
    • Newfoundlands
    • Poodles (miniature and toy)
    • Retrievers (Labrador and Golden)
    • Siberian huskies
    • Skye terriers
    • West Highland white terriers

Differential Diagnosis

Diagnosis and Screening

General Points

  • 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

Signs and History

  • Ectopic ureter
  • 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

  • Ureterocele
  • Other clinical signs can include:
    • Urine leakage while sleeping
    • Persistent wetness of fur near the perineum
    • Unpleasant odor
    • Dribbling urine after purposeful urination
    • Leaking urine when jumping around or excited

Physical Exam

  • Ureteral disorders may be associated with nonspecific exam findings
  • Findings can include:
    • Palpably enlarged kidney (due to hydronephrosis) or renal asymmetry
    • Abdominal pain
    • Fever
    • Hypersalivation
    • Loss of muscle mass
    • In severe cases with significant renal impairment:
      • Dehydration
      • Hypothermia
      • Tachypnea
      • Bradycardia
  • Abdominal distension due to uroabdomen/uroperitoneum may be noted in patients with ureteral trauma
  • Pets with chronic urinary incontinence may have discoloration of fur near the perineum, urine scalding, and/or associated dermatitis

Laboratory Tests

  • Routine laboratory tests
    • Complete blood count and biochemistry panel
      • May be unremarkable; useful in evaluating for presence of concurrent illness
      • Findings may include:
        • Anemia
        • Neutrophilic leukocytosis
        • Azotemia
        • Hyperkalemia
        • Hypercalcemia
        • Hypocalcemia
        • Hyperphosphatemia

    • Urinalysis
      • Recommended to screen for presence of crystalluria or concurrent urinary tract infection
      • Complete urinalysis should include specific gravity measurement, urine chemistry, and stained sediment analysis
      • Leukocytes in the urine, identified via urine dipstick, should be confirmed with sediment analysis
      • Findings may include:
        • Hematuria
        • Proteinuria
        • Pyuria
        • Bacteriuria

  • Urine culture and sensitivity testing
    • Recommended to confirm presence of infection and guide antimicrobial selection
    • Persistent incontinence increases risk for urinary tract infection

Imaging

  • A combination of survey abdominal radiography and ultrasound is recommended in all cases with suspected ureteral disease
  • Advanced imaging such as cystoscopy or contrast studies may be required; consider referral to a veterinary specialty center

  • Survey radiography
    • 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

  • Abdominal ultrasonography
    • 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 abdominal computed tomography (CT)
    • Contrast-enhanced CT is reliable for diagnosing ureteral strictures and compressions, ureteroliths, neoplasia, ectopic ureters, ureteroceles, and assessing the urogenital tract for concurrent anomalies

  • Antegrade pyelography
    • 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

  • Cystoscopy/Cystourethrovaginoscopy/urethrocystoscopy
    • 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

  • Excretory urography
    • Has largely been replaced by radiography, ultrasound, or CT for the diagnosis of ureteral disease

Prevention

  • Pets with a history of nephroliths or uroliths may benefit from long-term dietary or medical management to reduce risk of recurrence
  • 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

Medications

  • Antimicrobials
    • Recommended as part of the treatment for ureteroliths (dogs), cystitis, or pyelonephritis
    • For ureteroliths, a 4- to 6-week course of therapy is recommended
    • Antibiotic selection should be based on urine culture results
    • See Pyelonephritis and Lower Urinary Tract Infection for further information on antimicrobial selection

  • Medical management of ureteroliths
    • In dogs, medical dissolution can be attempted; however, placement of a ureteral stent is required
    • Antimicrobial therapy with dissolution diet should be continued until radiographs or ultrasound confirm dissolution of the ureterolith
      • Stent can be removed after dissolution is confirmed
    • Calcium oxalate ureteroliths are unresponsive to dietary or medical dissolution
      • 50% to 60% of ureteroliths in dogs and > 90% of ureteroliths in cats are calcium oxalate

  • Medical expulsive therapy (MET) for ureteroliths
    • 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 B Article

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 2 Abstract

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  • 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
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  • 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
  • Markovich JE, Labato MA. Medical management of nephroliths and ureteroliths. In: Bonagura JD, Twedt D, ed.'s. Kirk's Current Veterinary Therapy XV. Philadelphia:Elsevier Saunders;2014:892-6. Level 3

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.