Ureters

Question 1

What technique was described by Hardie 2023 in Vet Surg for complete ureteral bypass?

Answer 1

Bladder cuff nephrocystostomy

Question 2

In a study by Oyamada 2023 in Vet Surg, what combination of procedures was used to treat cats with proximal ureteral obstructions?

Answer 2

Extravesicular side-to-side neoureterocystostomy combined with renal descensus, ureterocystopexy and nephrocystopexy.

Question 3

In a study by Dirrig 2020 in JSAP, what percentage of cats had an abnormality detected on imaging post-SUB placement? What percentage of ureters became patent after SUB placement?

Answer 3

53% of cats had an abnormality on imaging following SUB placement - most frequently catheter kinking, obstruction, leakage or loose nephrostomy tube.

54% of obstructed ureters became patent following SUB placement.

Question 4

In a study by Milligan 2020 in JSAP, what was the most common complication with use of the SUB system in dogs for benign ureteral obstruction?

Answer 4

Device mineralization

Question 5

In ureteral injuries following OVH in cats and dogs what percentage demonstrated signs immediately post-operative in a study by Plater 2020 in JSAP? What percentage of patients had an excellent outcome following revision surgery?

Answer 5

58% of patients demonstrated immediate clinical signs. Bilateral ureteral involvement frequently resulted in anuria.

68% of patients had an excellent outcome following revision surgery (although 22% had a poor outcome).

Question 6

What surgical technique as described by Hoshi 2022 in JSAP for salvage of obstructive ureteral disease in cats is depicted?

Answer 6

Direct renal pelvicocystostomy using tube cystoplasty

Question 7

In a study by Taylor 2022 in VRU, what was the sensitivity and specificity of ultrasound for detecting ureteral ectopia in dogs as compared to cystoscopy?

Answer 7

Sensitivity and specificity of 94% and 100%, respectively.

Dogs with ureteral ectopia had a high incidence of concurrent urinary tract abnormalities.

Question 8

In a study by Butty 2021 in JFMS, what imaging technique was used to aid in SUB placement? What was the median survival time? Did concurrent ureterotomy and stone removal improve survival?

Answer 8

Ultrasound guided SUB placement was performed.

MST was 1555 days (see image for complications).

No improvement in survival was observed with concurrent stone removal. All stones removed were consistent with calcium oxalate.

Question 9

In a study by Dropkin 2021 in JFMS, what was successfully used to alleviate postoperative SUB obstruction due to clotting?

Answer 9

Alteplase (a tissue plasminogen activator) was infused either via the SUB port or transurethral catheter.

Compare to a study by Duval 2022 in JFMS who successfully used tEDTA to relieve SUB obstruction (69% success). In this study recurrence of obstruction was common (55%).

Question 10

In a study by Vrijsen 2021 in JFMS, what percentage of cats developed complications following SUB placement? What were the 4 most common complications? What percentage of cats underwent revision surgery? What was the MST?

Answer 10

80% of cats developed a complication. Older cats were more likely to develop a complication and were less likely to survive to discharge.

The most common complications were obstruction, UTI, pyelonephritis, and sterile cystitis.

MST was 274 days (compare to Butty 2022 in JFMS that reported a MST of 1555 days).

25% of cats underwent revision surgery.

Question 11

According to a study by Kennedy 2022 in JFMS, how much more likely was ureteral obstruction in cats fed a predominantly dry food diet?

Answer 11

16 times as likely as compared to predominantly wet food diet.

Question 12

In a study by Wuillemin 2021 in JVIM, what was the hospital discharge rate for cats undergoing SUB placement for benign ureteral obstruction? What 3 complications were commonly reported post-operatively? What percentage of cats required revision surgery? What was the MST?

Answer 12

94% of cats survived to discharge.

Luminal obstruction (17%), kinking (10%), and infection (26%) were the most common post-operative complications.

17% of cats required revision surgery.

MST was 821 days.

Question 13

What potential late complication of SUB placement in cats was reported in a study by Veran 2022 in JVIM?

Answer 13

Transmural migration within the digestive tract. Occurred at a median of 928 days post-operative.

7/15 cats had obstruction of the SUB device and a positive urine culture.

Question 14

In a study by Merindol 2023 in JVIM, what was the success rate of medical management for benign ureteral obstruction?

Answer 14

Complete success in 30% (23% success for uroliths which made up the majority [73%] of obstructions). A higher success rate was reported for distal and smaller uroliths.

Question 15

What is the normal luminal diameter of the canine and feline ureter?

Answer 15

Feline: 0.4mm
Canine: 0.07 times the length of L7

Question 16

What percentage of cats have a circumcaval ureter?

Answer 16

Right (31%), left (1.3%), bilateral (3.3%).

Question 17

In relation to the renal artery and vein, where does the ureter exit the renal pelvis?

Answer 17

Dorsolateral to the renal artery and vein.

Question 18

What is the vascular supply to the ureter?

Answer 18

The ureteral artery, arising from the caudal aspect of the renal artery, runs caudally along the adventitial surface of the ureter and anastomoses with the ureteric branch of the caudal vesicular artery.

Question 19

What are the layers of the ureter?

Answer 19

The outer adventitial layer, central muscular layer (50% of ureteral wall thickness; inner and outer longitudinal and middle circular), and inner mucosal layer.

Question 20

Following ureteral obstruction how much does renal blood flow decrease at 24-hours and 2-weeks as compared to normal?

Answer 20

40% of normal at 24-hours, 20% of normal at 2-weeks.

Question 21

What is the return of function in kidneys obstructed for 1 weeks and 2 weeks following unobstruction?

Answer 21

1-week: 65% return of GFR over 5-weeks.
2-weeks: 46% return over 4 months.

Question 22

What are some treatment options for feline ureterolithiasis?

Answer 22

1. Medical management (diuresis, amitriptyline).
2. Ureteral stent
3. SUB
4. Ureteral resection with reimplantation.
5. Ureterotomy.

Question 23

Why is extracorporeal shockwave lithotripsy not used for treatment of feline ureterolithiasis?

Answer 23

It may result in renal injury.

Question 24

What are three important presurgical considerations for cats undergoing surgical correction of ureterolithiasis?

Answer 24

1. The degree of damage to the obstructed kidney is unknown.
2. Renal disease may be progressive even after relief of the obstruction.
3. If the cat is azotemic, renal function in the contralateral kidney must be impaired.

Question 25

What are reported complications of ureteral stenting in cats?

Answer 25

Stranguria/pollakiuria, imperfect stent location, ureteral trauma during placement, UTI. Removal required in 27% of cases due to obstruction or dysuria.

Question 26

Is normograde or retrograde ureteral stent placement preferred in cats?

Answer 26

Normograde; guidewire is placed through the greater curvature of the kidney and into the ureter. This is followed by a ureteral dilator and then double-pigtail indwelling catheter.

Non-surgical cystoscopic placement of stents has also been reported in female cats, but only successful in 19% of cases.

Question 27

What are some complications associated with the SUB device?

Answer 27

Occlusion (13%), blood clots (3%), kinking (3%), urine leakage.

Question 28

What percentage of cats suffer uroabdomen after ureterotomy for ureteral stone removal?

Answer 28

12%. Although not investigated, waiting to see if the uroabdomen resolves with the use of abdominal drainage may be reasonable.

Question 29

What are the most common ureterolith compositions in dogs?

Answer 29

Struvite, or calcium oxalate. Staph and E.coli commonly cultured.

Concurrent nephroliths and cystoliths are common (50% of cases).

Question 30

What treatment options are available for dogs with obstructive ureterolithiasis?

Answer 30

1. Lithotripsy.
2. Ureterotomy.
3. Neoureterocysostomy (end-to-side).
4. Ureteral stenting.

Question 31

Are nephroliths or ureteroliths more difficult to fragment in dogs with extracorporeal shockwave lithotripsy?

Answer 31

Ureteroliths.

Question 32

Do retrocaval ureters cause obstruction in cats?

Answer 32

Unknown, but could potentially impede ureterolith migration resulting in secondary urethral injury and stricture.

Question 33

What are potential causes of ureteral injury following OVH?

Answer 33

Inadvertent ligation, transection, resection or obstruction secondary to uterine, ovarian or vaginal granuloma formation.

Rarely ureterovaginal fistula may develop secondary to encircling ligature around the uterine stump incorporating the distal ureter.

Question 34

How is blunt trauma to the ureter diagnosed?

Answer 34

Biochem: azotemia (more severe if abdominal rather than retroperitoneal leakage).

Imaging: Loss of abdominal detail on radiographs or retroperitoneal streaking.

Fluid analysis: increased creatinine and potassium compared to serum.

Excretory urography, CT pyelography, and retrograde or antegrade pyelography can be used to identify the site of injury.

Question 35

What are surgical treatment options for ureteral injuries?

Answer 35

Proximal: ureteronephrectomy, ureteral ligation and SUB placement.

Distal: ureteral reimplantation.

Question 36

What is a urinoma?

Answer 36

A collection of urine within the retroperitoneum that causes fat necrosis and reactive fibrosis. Often secondary to trauma.

Treatment involves ureteronephrectomy with ablation or omentalization of the urinoma cavity.

Question 37

Are intramural or extramural ureters more common or cats and dogs?

Answer 37

Cats: Extramural.
Dogs: Intramural.

Question 38

How much more likely are female dogs to be diagnosed with ureteral ectopia than males?

Answer 38

20 times as likely.

Golden retrievers and labradors are at increased risk.

Question 39

What imaging techniques can be used to assess suspected ureteral ectopia?

Answer 39

Excretory urography (+/- pneumocystography), fluoroscopic excretory urography, vaginocystography, ultrasound, endoscopy, CT.

CT more accurate than fluoroscopic excretory urography. Urethrography unreliable.

Question 40

What are options for intramural ectopic ureter repair?

Answer 40

1. Cystoscopic laser ablation
2. Side-to-side neoureterocystostomy.

Question 41

What is the surgical treatment for extramural ectopic ureter repair?

Answer 41

End-to-side neoureterocystostomy (intravesicular or extravesicular technique).

Question 42

What percentage of dogs regain continence after treatment of ectopic ureters?

Answer 42

22-72%, with another 7-28% of dogs becoming continent with additional medical management (i.e. phenylpropanolamine).

Question 43

Is the outcome of male dogs treated for ectopic ureters better or worse than for females?

Answer 43

Generally better, perhaps due to increased pressure within the prostatic urethra.

Question 44

When should surgical correction rather than laser ablation be considered for male ectopic ureters?

Answer 44

If the ureter is extramural, dogs too small to accept a 2.7mm cystoscope, or if the ureteral orifice is too small to enter with a laser fiber. A perineal approach can also potentially be used for cystoscope placement.

Question 45

What is a ureterocele?

Answer 45

A dilatation associated with the distal ureter or ureteral orifice that occurs secondary to faulty embryonic development.

Can be orthotopic (ureter in correct location) or ectopic (within the wall of the bladder or urethra, generally associated with ectopic ureter).

Question 46

What are clinical signs associated with ureterocele?

Answer 46

Hydronephrosis, chronic UTI, urinary incontinence.

Question 47

How is ureterocele diagnosed?

Answer 47

Ultrasound, contrast cystogram, excretory urogram.

Question 48

What is the surgical treatment for ureterocele?

Answer 48

Resection of the ureterocele +/- neoureterocystostomy (if ectopic ureter).

Question 49

What is a common location of feline ureteral obstruction secondary to urolithiasis?

Answer 49

The left ureter ~3cm distal to the kidney at the location of a ureteral bend.

10-15% of cats with right sided ureteroliths also have a retrocaval ureter and may require retraction of the cava for removal.

Question 50

How is the ureter stabilized during ureterotomy?

Answer 50

Passage of right angled forceps around the ureter and spreading of the jaws.

Question 51

How can suturing of the back wall of the ureter be prevented during ureterotomy closure?

Answer 51

Passage of a short piece of suture material (2-0 to 4-0) into the ureter to act as a stent.

Closure is performed through the adventitia and muscularis (7-0 to 10-0 nylon is used for cats).

Question 52

What is the major complication associated with use of traditional nephrostomy tubes (red rubber or Foley catheters) following ureterotomy?

Answer 52

Postoperative uroabdomen (24%). Overall complication rate of 50%.

Use of double-pigtailed stents has reduced these complications. Ureteral stenting may also obviate the need for ureterotomy.

Question 53

What surgical technique is shown?

Answer 53

Intravesicular end-to-side neoureterocystostomy.

Question 54

What are options for tension reduction on end-to-side neoureterocystostomy in instances of proximal ureteral pathology?

Answer 54

Renal descensus, pexying the apex of the bladder to the caudal pole of the kidney or iliposoas muscle.

Question 55

Is post-operative uroabdomen more common after ureterotomy or ureteral reimplantation in cats?

Answer 55

No difference (~15% for both). Persistent ureteral obstruction more common with ureteral reimplantation.

Question 56

What are the two described techniques for side-to-side neoureterocystostomy?

Answer 56

1. Ligation of the ectopic ureter distal to the created stoma
2. Dissection and removal of the ectopic ureter distal to the stoma (theoretically removes the risk of recanalization of the ureter, although no difference in post-operative incontinence was observed between groups).

Question 57

What is the outcome following side-to-side neoureterocystostomy for treatment of intramural ectopic ureters?

Answer 57

43% of dogs remain incontinent in combination with medical management.

Question 58

What surgical technique is shown?

Answer 58

Intramural ectopic ureter correction (neoureterocystostomy) with dissection of the distal ureter.

Question 59

What surgical technique is shown?

Answer 59

Intramural ectopic ureter correction (neoureterocystostomy) with ligation of the distal ureter.

Question 60

Should nephroliths be removed at the same time as surgery for ureteral obstruction, if present?

Answer 60

Concurrent nephroliths present in 62% of cats with ureteral obstruction. Controversial as to whether or not to remove.

Nephrotomy may damage renal parenchyma (10-20% reduction in GFR), but failure to remove may result in reobstruction (40% in one study).

Question 61

When might pyelotomy be considered?

Answer 61

If the renal pelvis is markedly dilated allowing direct incision without risk of damage to the hilar vasculature. Closed with SC or interrupted pattern of 5-0 to 7-0 absorbable suture.

Question 62

Ureteral discontinuity of what length will heal with a ureteral catheter left in place?

Answer 62

5cm has healed experimentally, but the muscularis is replaced with fibrous tissue.