Ch 115 - Ureters

Question 1

What % of felines have circumcaval ureters?

Answer 1

• Right 30.6%
• Left 1.3%
• Bilateral 3.3%

7% have a double cava

Question 2

List the layers or the ureter

Answer 2

• Outer adventitial layer
• Central muscular layer
• Inner mucosal layer (lamina propria and transitional epithelium)

Question 3

What is the response in terms of ureteral pressure in response to acute ligation?

Answer 3

Ureteral pressures increase and peak by 5 hours and then lessen but remain elevated for 12-24hr

Question 4

What is the response of renal blood flow after acute ureteral ligation?

Answer 4

• 24hr - 40% of normal
• 2 weeks - 20% of normal

Results in a decreased GFR and a compensatory increased GFR in the contralateral kidney

Question 5

What cellular response is seen in response to acute ureteral ligation?

Answer 5

• Influx of macrophages and T-lymphocytes
• Macrocyte proteolytic enzymes and cytokines resilt in fibroblast recruitment and activation
• Interstitial fibrosis or glomerulosclerosis

Question 6

What is the expected return of GFR after ureteral obstruction in previouslt healthy kidneys?

Answer 6

• 1 week obstruction - 65% of normal GFR over 5wk
• 2 week obstruction - 46% of normal over 4m

Slight, moderate and severe fibrosis occurs over 1, 2 and 3 weeks respectively

Question 7

List important points to discuss with the owner in a cat with ureteral obstruction

Answer 7

• Cannot predict how long the obstruction has been presetn and how well the cat will recover
• Most have some degree of chronic interstitial nephritis which will progress despite surgery
• If azotaemic with unilateral obstruction, cat has bilateral kidney disease
• Significant risk of complications - overall mortality 18-21%

Question 8

List options for surgical management of ureteral obstruction

Answer 8

• Ureteral resection with reimplantation
• Ureterotomy
• Double-pigtail ureteral stent
• SUB
• Ureteral resection and anastomosis
• Lithotripsy

Question 9

What % of cats need removal or replacement of a double pigtail stent?

Answer 9

27% - stent occlusion or dysuria

Question 10

List complications associated with a SUB

Answer 10

• Urolith occlusion 13%
• Occlusion with blood clot under 3%
• Kinking 3%
• Urine leakage - rare
• Infection
• Migration into intestines

Question 11

What is the % of reported urine leakage after a ureterotomy?

Answer 11

6-12%

May heal on its own with draining from an abdominal or nephrostomy drain

Question 12

What are the most common ureteroliths in dogs?

Answer 12

• Struvite and calcium oxalate

Question 13

What is the most common primary ureteral neoplasia in dogs?

Answer 13

Benign fibroepithelial polyps

DDx: leimyoma, TCC, sarcoma, MCT

Question 14

Where are congenital ureteral strictures most commonly located?

Answer 14

Ureteropelvic junction

Question 15

What is a urinoma?
What is the treatment?

Answer 15

A collection of urine within the retroperitoneal space that causes fat necrosis and subsequent reactive fibrosis

Tx: ureteronephrectomy with ablation or omentalisation of the urinoma cavity

Question 16

What breeds and sex are overrepresented for ectopic ureters?

Answer 16

• Skye terriers
• Golden retrievers
• Labs
• Huskies
• Newfies
• Bulldogs
• WHWT
• Fox terriers
• min and toy Poodles

Females are 20x more likely

Question 17

What is the sensitivity and specificity of CT for diagnosing ectopic ureters?

What other imaging technique is highly valuable?

Answer 17

• 91 and 100%
• Endoscopy of the vagina, urethra and bladder

Question 18

What is the prognosis after surgical repair of ectopic ureters?

Answer 18

• Continence in 22-72%
• Additional 7-28% become continent with medical management

Those with continued incontinence likely have a functional abnormality of the bladder neck and urethra

Question 19

List the treatment options for ectopic ureters

Answer 19

Neoureterocystostomy (extramural)
- End-to-side intravesicular or extravesicular
- Side-to-side

Cystoscopic guided laser ablation (intramural)

Question 20

How does the prognosis of ectopic ureters differ for males as apposed to females

Answer 20

Males seem to have a better outcome
- 5/5 and 9/11 continent after neoureterocystostomy
- 4/4 continent with laser ablation
- Longer urethra, increased pressure within prostatic urethra

Question 21

What is the major difference regarding ectopic ureters in cats vs dogs

Answer 21

Majority of cats are extramural

Question 22

What is a ureterocoele?
What are the subtypes?
Treatment?

Answer 22

Dilatation assoc with the distal ureter or ureteral orifice that occurs as a faulty embryonic development (Chwalla membrane fails to regress)
- Orthotopic/intravesicular - Ureteral orifice in normal positionand entire ureterocoele is within the bladder
- Ectopic - If any portion of ureterocoele is within the bladder neck or urethra

Treatment: Resection of the ureterocoele (ureterocoelectomy) +/- neoureterocystostomy (if ectopic)

Question 23

What is used as a temporary stent when suturing a ureterotomy site?

Answer 23

2-0 to 4-0 suture material

Question 24

What are the 2 options for end-to-side neoureterocystostomy?

Answer 24

• Intravesicular - vental cystotomy performed to pull ureter from outside in and suture mucosa to mucosa after spatulating the ureter
• Extravesicular - no cystotomy required, sutured to mucose with knows external

Cats with contralateral nephrectomy had creatinine concentrations reduce more rapidly with extravesicular technique

Question 25

List options for tension reduction for a neoureterocystostomy

Answer 25

• Renal descensus
• Pexy apex of bladder to caudal pole of kidney
• Pexy apex of bladder to iliopsoas muscle (psos cystopexy)

Question 26

What is the prognosis for reimplantation vs ureterotomy

Answer 26

• Similar rates of uroabdomen (15% reimplantation vs 16% ureterotomy)
• Persistent obstruction more common after reimplantation (11% vs 3%)

Question 27

What is the reported reduction in GFR after a nephrotomy in feline kidneys?

Answer 27

• 10-20% reduction over 78 weeks