Urogenital Surgery

Question 1

What is the most common reason to perform urinary tract surgery?

Answer 1

Urolithiasis

Question 2

How can we identify stones in the urine?

Answer 2

Can only identify them if we send it off for testing but can make a good guess depending on chemical environment

Question 3

Which one is the most common bladder stone?

Answer 3

Struvite (Magnesium ammonium phosphate)

Question 4

How do struvite stones form?

Answer 4

They form when there is a urinary tract infection from urease producing bacteria which make the urine more alkaline - struvite stones form in alkaline urine

more common in females than in males as UTI more common in females due to short and wide urethra

Question 5

What are the second most common stones that could be present in the urine and how/why do they form?

Answer 5

Calcium Oxalate - “metabolic stone”

They form when there is an excess calcium excretion in the urine.
they like to form in acidic urine, (also Cushing’s or acidosis) they are most radiopaque (due to the calcium)
males>females
these stones are not smooth like struvite, they have spicules on them

Question 6

Which stone forms when there is a defect in protein metabolism?

Answer 6

Urate (less common)

occurs from a defective uric acid cycling. Congenital (dalmatian, bulldog) but also seen in portosystemic shunt and liver failure.
They are radiolucent (more challenging to identify)

Question 7

Why is an obstruction through uroliths more of a concern in males rather than females?

Answer 7

Males have a thing and long urethra that is highly muscular (smooth and striated) whereas females have a membranous, shorter, wider, less muscular urethra

Question 8

How do we diagnose stones in the urinary tract?

Answer 8

History, signalment: most common presentation is straining to urinate (stranguria)
Urinalysis: pH, crystalluria, culture
Radiographs/ultrasound: radiographs most helpful (the 2 most common stones struvite and calcium are radiopaque)

Question 9

How do we treat uroliths?

Answer 9

Medical dissolution: treating the infection and changing the diet which can change the pH of the urine and the urinary. Struvite, urate and cystine are dissolvable stones. Treat with diet and AB, not successful if they are big stones

Surgery: removal, (lithotripsy - in most cases not a practical solution and not readily available)

Bypass: obstructive ureterolithiasis

Question 10

When would a nephrotomy be indicated? (incision into kidney)

Answer 10

Only ever indicated when medical management has failed!

Indications for surgery are:
- Nephrolithiasis (if big and causes obstruction)
- Source of infection
- Haematuria of renal origin

Effect on renal function??

Question 11

Is a ureteral obstruction a medical emergency?

Answer 11

Yes!
If identified - surgery as soon as possible
- Non-specific clinical signs (as other kidney may still function fine)
- Not all are azotemic
- Can cause acute kidney injury

Question 12

How can we surgically treat ureteral obstruction?

Answer 12

Surgery depends on location
- Ureteral reimplantation (only for distal ureter)

• Ureterotomy or resection/anastomosis are not really done anymore as the complication risk is high - leaks

Question 13

What would be a salvage procedure to surgically treat ureteral obstruction?

Answer 13

Ureteral stenting - salvage! when there is no other option available
- stent is passed up ureter past the blockage, distends and urine can flow past the blockage

Question 14

What would be the surgical treatment option if there is a stone in the proximal ureter or mid ureter?

Answer 14

SUBS - salvage!
Subcutaneous Ureteral Bypass System

Question 15

What are the clinical signs of bladder stones/urethral stones?

Answer 15

Nothing - if only in bladder (apparently?!)
- Bladder infection
- Dysuria/stranguria
- Haematuria
- Urethral obstruction (unable to urinate, big bladder, sick - azotemic due to obstruction)

Question 16

How do we treat bladder stones/urethral stones?

Answer 16

1. Flush ureteral stones back into bladder (is successful surgery won’t be an emergency but do as soon as practically possible)
2. Cystotomy
3. Stone removal

In medical emergency: Urinary diversion - urinary catheter - attempt retrohydropulsion
(pass urinary catheter to level of obstruction, then occlude on pelvic brim rectally with finger - push in front of stone to occlude urethra, then flush in saline and feel distension, then let go with finger and stone should be flushed back) - However this is creating an increased pressure and there might already be a very full bladder present in the patient - can avoid this if doing retrohydropulsion intra operatively when doing a ventral cystotomy.

Question 17

How are we performing a cystotomy?

Answer 17

To be able to perform a cystotomy do a caudal coeliotomy from the umbilicus to the pubis, put stay sutures in bladder to handle atraumatically (bladder very sensitive organ)
- identify and protect ureteral orifices ALWAYS do ventral cystotomy
- gentle handling