Chapter 115 Ureters Flashcards
What is reported cross sectional size of feline and canine ureter?
Cats 0.4mm (0.8mm stent passage reported)
Dogs 0.07 x Lenght L2. 2.0 - 2.5mm on CT
Where does ureter sit in relation to renal vessels
Dorsolateral
What was reported rate of feline retrocaval ureter?
What was side distribution?
35%
31% right side, 1% left side, 3% bilateral
What is the blood supply to the ureter?
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)
What are the layers of the ureter?
- 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.
Briefly describe pathophysiology of ureteral obstruction
- 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
What % of pre-injury GFR returned in dogs wit 1 week of ureteral obstruction? How long did it take?
And after 2 weeks obstruction?
65% GFR, peaked after 5 weeks
46%, after 4 months
What drug has been used to induce ureteral relaxation?
Amitryptiline (10mg/cat sid)b –> passage of 4/4 stones
(Glucagon + calcium channel blockers reported in other species)
What was 1 and 2 year survival of cats managed medically for ureterolithiasis, vs surgically
Medical: 66% and 66%
Surgical: 91% and 88%
Why is extracorporeal lithotripsy not used in cats?
May result in renal injury when applied to concomitant nephroliths
What was overall mortality and most common complication in cats undergoing ureterotomy for managemen of ureterolithiasis?
20% mortality
Uroabdomen (10% of cases)
List 4 surgical options for management of feline ureterolithiasis
List an additional option for dogs and what should be noted re this option
- 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
In cats undergoing placeent of ureteral stent for management of ureterolithiasis, what % required stent removal/replacement?
27%
Due to occlusion and dysuria
What is the jelly part of SUB port made of
Silicone
What is reported occlusion rate of SUB?
10-20%
8% reported with 3-6 monthly flushing
What are most common canine uereteroliths?
Culture results?
Struvite or calcium oxalate
Almost all positive (Staph or E coli)
(Half of dogs had concomitant nephrolith or cystolith)
What is most common reported primary neoplasm of ureter
List 5 other ddx
- 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)
Where do congenicat ureteral strictures usually occur?
Ureteropelvic junction, bilaterally
Usually PTS, but one case report of stents in a pug
List a postential sequalae of spay related ureteral trauma
Ureterovaginal fistula (if ligature encircling ureter + uterine stump)
What type of trauma has been reported to –> ureteral injury.
Name a potential longer term sequale.
How is it treated
Blunt trauma
Urinoma = uroretroperitoneum –> fat necrosis and fibrosis. N.B. Dont confuse with paranephric pseudocysts.
Tx ureteronephrectomy + omentalisation or ablation of urinaoma cavity
IS there a sex predilection for ureteral ectpia?
Female!
Up to x20 more likely
Are intra-or extramural ectopic ureters most common in dogs?
And cats
Dogs mainly intramural
Cats extramural
Name 3 imaging modalities that can be used for work up of ectopic ureters
- 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)
List 3 management options for intramural ectopic ureters
- 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
What % of incontinence is resolved followign ureteral ectopia surgery (in female dogs)?
25-75%
If on-going incontinence its liekly there os some functional abnormality of bladder neck/urethera - documented in a urodynamic evaluation study.
How does sucess rate (re incontinence) differ in male dogs (vs female)
And in cats/
Better in male dogs and cats
How are ureterocoeles subclassified?
Orthotopic/intravesicular OR ectopic
failure of regression of what structurure is thought to lead to ureterocoele
Chwalla membrane (separates common excretory duct and ureter)
What are usual clinical signs of ureterocoele?
C/s of UTI, pollaiuria/stranguria if bladder neck obstruction (hydronephrosis), incontinence of associated with ectopic ureter
What are sx options for ureterocoele
- Ureterocoelectomy
- Neoureterocystostomy
- (or ureteronephrectomy)
- Cystoscopic ablation reported in dog during our reading list - one ectopic ureterocoele and one orthotopic with ureterovesicular stenosis
Comment on use of nephrostomy tubes after ureterotomy
–> 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.
Name two techniques for ureteral re-implantation
Intravesicular and extravesicular
List 3 techniques for adressing tension on ureteral re-implantation site
Renal descensus
Bladder pexy (psoas cystopexy)
Boari flap
What does urethral-trigonal reconstruction refer to?
Side-to side neoureterocystostomy where distal part of intramural ureter is dissected out of bladder wall.
What is significance of nephroliths concurrent with ureteroliths
Warn owners re future migration into ureter
What is the difference in a ureter that has been left to heal (over a gap in continuity!) vs normal ureter
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!
