Chapter 115 Ureters

Question 1

What is reported cross sectional size of feline and canine ureter?

Answer 1

Cats 0.4mm (0.8mm stent passage reported)

Dogs 0.07 x Lenght L2. 2.0 - 2.5mm on CT

Question 2

Where does ureter sit in relation to renal vessels

Answer 2

Dorsolateral

Question 3

What was reported rate of feline retrocaval ureter?

What was side distribution?

Answer 3

35%

31% right side, 1% left side, 3% bilateral

Question 4

What is the blood supply to the ureter?

Answer 4

Cranial ureteral artery (branch from renal artery), anastomoses with caudal ureteral arery.

Caudal ureteral artery is a branch of caudal vesicular artery (which comes from either prostatic or vaginal artery)

Question 5

What are the layers of the ureter?

Answer 5

• Adventitia
• Muscularis
  
  • 50% of thickness
• Mucosa
  
  • Lamina propria, 30% thickness
  • Epithelium, 15% thickness

Transverse photomicrographs of a canine (A) and feline (B) ureter (bars = 200 µm; hematoxylin and eosin stain). The muscularis (arrow), lamina propria (asterisk), and transitional epithelium or mucosa (arrowhead) are shown.

Question 6

Briefly describe pathophysiology of ureteral obstruction

Answer 6

• Ureteral pressures increase
• Transient increased renal blood flow but decreased to 40% within 24 hours (20% after 2 weeks)
• Reduced GFR
• Leukocyte and fibroblast influx. Fibroblasts may –> fibrosis

Question 7

What % of pre-injury GFR returned in dogs wit 1 week of ureteral obstruction? How long did it take?

And after 2 weeks obstruction?

Answer 7

65% GFR, peaked after 5 weeks

46%, after 4 months

Question 8

What drug has been used to induce ureteral relaxation?

Answer 8

Amitryptiline (10mg/cat sid)b –> passage of 4/4 stones

(Glucagon + calcium channel blockers reported in other species)

Question 9

What was 1 and 2 year survival of cats managed medically for ureterolithiasis, vs surgically

Answer 9

Medical: 66% and 66%

Surgical: 91% and 88%

Question 10

Why is extracorporeal lithotripsy not used in cats?

Answer 10

May result in renal injury when applied to concomitant nephroliths

Question 11

What was overall mortality and most common complication in cats undergoing ureterotomy for managemen of ureterolithiasis?

Answer 11

20% mortality

Uroabdomen (10% of cases)

Question 12

List 4 surgical options for management of feline ureterolithiasis

List an additional option for dogs and what should be noted re this option

Answer 12

• Ureterotomy
• Resection + re-implantation
• Stent (cystoscopic (but only 20% success) or open surgical
• SUB

Can do extracorporeal shockwave lithotripsy in dogs - often need more than 1 treatment

Question 13

In cats undergoing placeent of ureteral stent for management of ureterolithiasis, what % required stent removal/replacement?

Answer 13

27%

Due to occlusion and dysuria

Question 14

What is the jelly part of SUB port made of

Answer 14

Silicone

Question 15

What is reported occlusion rate of SUB?

Answer 15

10-20%

8% reported with 3-6 monthly flushing

Question 16

What are most common canine uereteroliths?

Culture results?

Answer 16

Struvite or calcium oxalate

Almost all positive (Staph or E coli)

(Half of dogs had concomitant nephrolith or cystolith)

Question 17

What is most common reported primary neoplasm of ureter

List 5 other ddx

Answer 17

• Fibroepithelial polyp most common

Other ddx:

• TCC
• SCC
• MCT
• Leiomyoma
• Leiomyosarcoma
• Other sarcomas
• (not neoplastic but book mentions granulomatous ureteritis, and retroperitoneal thrombosis –> periureteral fat necrosis as ddx for ureteral mass)

Question 18

Where do congenicat ureteral strictures usually occur?

Answer 18

Ureteropelvic junction, bilaterally

Usually PTS, but one case report of stents in a pug

Question 19

List a postential sequalae of spay related ureteral trauma

Answer 19

Ureterovaginal fistula (if ligature encircling ureter + uterine stump)

Question 20

What type of trauma has been reported to –> ureteral injury.

Name a potential longer term sequale.

How is it treated

Answer 20

Blunt trauma

Urinoma = uroretroperitoneum –> fat necrosis and fibrosis. N.B. Dont confuse with paranephric pseudocysts.

Tx ureteronephrectomy + omentalisation or ablation of urinaoma cavity

Question 21

IS there a sex predilection for ureteral ectpia?

Answer 21

Female!

Up to x20 more likely

Question 22

Are intra-or extramural ectopic ureters most common in dogs?

And cats

Answer 22

Dogs mainly intramural

Cats extramural

Question 23

Name 3 imaging modalities that can be used for work up of ectopic ureters

Answer 23

• Contrast CT/radiography/fluoroscopy: CT more useful in identifying distal ureteral morthology in dogs, cf fluoro excretory urography or fuoro urethrography in a study.
• Ultrasonography
• Cystoscopy (100% correlation between cystoscopic and surgical findings in 23 dogs)

Question 24

List 3 management options for intramural ectopic ureters

Answer 24

• Cystoscopic laser treatment
• Side to side neuureterocystostomy
  
  • Either distal ureter is dissected out of bladder wall, or
  • Distal ureter is ligated (sutures placed from outside of bladder in - avoid penetration of bladder mucosa) - risk recanalization but preferred surgical method

Question 25

What % of incontinence is resolved followign ureteral ectopia surgery (in female dogs)?

Answer 25

25-75%

If on-going incontinence its liekly there os some functional abnormality of bladder neck/urethera - documented in a urodynamic evaluation study.

Question 26

How does sucess rate (re incontinence) differ in male dogs (vs female)

And in cats/

Answer 26

Better in male dogs and cats

Question 27

How are ureterocoeles subclassified?

Answer 27

Orthotopic/intravesicular OR ectopic

Question 28

failure of regression of what structurure is thought to lead to ureterocoele

Answer 28

Chwalla membrane (separates common excretory duct and ureter)

Question 29

What are usual clinical signs of ureterocoele?

Answer 29

C/s of UTI, pollaiuria/stranguria if bladder neck obstruction (hydronephrosis), incontinence of associated with ectopic ureter

Question 30

What are sx options for ureterocoele

Answer 30

• Ureterocoelectomy
• Neoureterocystostomy
• (or ureteronephrectomy)
• Cystoscopic ablation reported in dog during our reading list - one ectopic ureterocoele and one orthotopic with ureterovesicular stenosis

Question 31

Comment on use of nephrostomy tubes after ureterotomy

Answer 31

–> higher rate of uroabdomen (25%, vs 12% without) and overall 50% complication rate.

May be improved with pigtail nephrostomy tubes.

Now usually use abdo drains.

Question 32

Name two techniques for ureteral re-implantation

Answer 32

Intravesicular and extravesicular

Question 33

List 3 techniques for adressing tension on ureteral re-implantation site

Answer 33

Renal descensus

Bladder pexy (psoas cystopexy)

Boari flap

Question 34

What does urethral-trigonal reconstruction refer to?

Answer 34

Side-to side neoureterocystostomy where distal part of intramural ureter is dissected out of bladder wall.

Question 35

What is significance of nephroliths concurrent with ureteroliths

Answer 35

Warn owners re future migration into ureter

Question 36

What is the difference in a ureter that has been left to heal (over a gap in continuity!) vs normal ureter

Answer 36

Healed segment will still be covered with urothelium but muscularis is priarily fibrous tissue!

Healing reported across 5cm gap as long as ureteral catheter left in place!