Soft Tissue Surgery: Urinary Incontinence

Question 1

What controls the bladder filling and storage phase?

Answer 1

Primarily sympathetic via hypogastric nerve
* Beta-adrenorecpetors in detrusor- relaxation
* Alpha-adrenoreceptors in urethral smooth muscle and trigone (contraction)

Somatic (voluntary) nervous system via the pudenal nerve
* Urethral striated muscle contraction
* Inhibition of detrusor reflex

Question 2

What controls bladder empyting phase?

Answer 2

Parasympathetic nervous system predominated via the pelvic nerve
* Stimulation of stretch receptors in bladder wall
* Contraction of detrusor muscle
* Relaxation of the urethral muscle

Detrusor muscle

Question 3

What allows urinary continence?

Answer 3

• Brainstem micturition centre integrates urethral and detrusor function
• Cerebral cortex gives voluntary control by over-riding the detrusor reflex

Question 4

How should urinary incontinence be investigated?

Answer 4

• Detailed history
• Clinical examination
• Biochemistry and haematology
• FeLV test
• Urinaylsis
• Urine culture and sensitivity
• Observe patient urinating

Question 5

Following clinical exam what further investigations are indicated for urinary incontinence?

Answer 5

• Plain abdominal radiographs- useful screening procedure
• IV urogram/CT angiography
• Retrograde urethrogram
• US of urinary tract

Question 6

What are normal findings of the filling phase?

Answer 6

• Patients can urinate normally
• Patients can empty bladder normally
• Patients dribble urine between urinations
• Patients often have reduced bladder capacity

Question 7

What are differentials of abnormalities of filling phase?

Answer 7

• Ectopic ureter- congenital/acquired
• Reduced pressure at the bladder neck
• Involuntary contractions

Question 8

What can cause reduced pressure at the bladder neck?

Abnormality of filling phase

Answer 8

• Congenital USMI
• Acquired USMI
• Intrapelvic/caudal bladder, short urethra, hypoplastic bladder
• Bladder neck mass
• Urethral dysplasia (female cats)

USMI- urethral sphincter mechanism incompetence

Question 9

What can cause involuntary contractions?

Answer 9

• Bacterial infection
• Cystic calculus
• Drug induced
• Felv
• Neoplasia of bladder neck

Question 10

What are the DDx of abnormalities of emptying phase?

Answer 10

• Partial/complete urethral obstruction
• Chronic distension of bladder- urethral obstruction, pelvic trauma, disc protrusion, feline dysuatonomia
• Dyssynergia- urethral spasm during bladder contractoin, urine dribbling

Question 11

What is USMI?

Answer 11

Urethral spincter mechanism incompetence
* Commenest cause of incnotinence in bitch
* Intermittent involuntary passage of urine
* Usually while dog is relaxed
* Can urinate normally
* Acquired and congenital forms

Question 12

What can cause USMI?

Answer 12

• Low urethral tone- striated muscle tone reduced
• Hormonal influence- spayed, prior to 1st season
• Obesity
• Intrapelvic bladder

Question 13

What breeds are predisposed to acquired USMI?

Answer 13

• Dobermans
• Boxers
• Irish setters
• OESD

Question 14

When are congenital USMIs found?

Answer 14

Juvenile bitches- prior to 1st season
50% resolve after 1st season

Ectopic ureter is main DDx

Question 15

How is USMI treated medically?

Answer 15

Increase muscle tone
* phenylpropanolamine or ephedrine
* Oestriol

Reduce contributing factors
* Weight loss
* Treat secondary UTI

Question 16

How can USMI be treated surgically?

Answer 16

• Colposuspension
• Urethropexy
• Combo of above
• Artificial urethral sphincter
• Submucosal urethral injections of bulking agents

Question 17

How is acquired USMI treated in male dogs?

Rare

Answer 17

• Phenylpropanolamine
• Weight loss
• Surgery- vas deferensopexy, prostatopexy, hydraulic occluder

Question 18

What is an ectopic ureters?

Answer 18

Congenital anomaly, ureter bypasses bladder to empty into urethra, vagina or rectum
* Intramural
* Extramural

Congenital USMI or hypoplastic bladder may co-exist
Secondary UTIs are common

Question 19

If ectopic ureter is suspected what should be checked on physical examination?

Answer 19

External genitalia
* wet or dry
* Inflammed
* Normal appearance

Abdominal palpation
* Palpable bladder

Question 20

How are ectopic ureters treated?

Answer 20

• Treatment of associated UTI
• Early surgical managment
• Technique depens on uni/bilateral and intra/extramural

Question 21

What are the different surgical treatments for ectopic ureters?

Answer 21

• Exploratory coeliotomy
• Cystotomy to assess trigone area
• Ureteronephrectomy
• Ureteral transection and re-implantation
• Intravesical repair

Question 22

What are the different causes of feline urinary incontinence?

Uncommon

Answer 22

• Neurogenic most common cause- tail pull, sacral fracture
• Juvenile urinary incontinence- ectorpic ureter, hypoplastic urethra
• Iatrogenic- perineal urethrostomy

Question 23

What are the different causes of ureteric obstruction?

Answer 23

Intraluminal
* Ureteric calculus
* Pedunculated mass

Intramural
* tumour
* fibrosis

Extramural
* Compression or invasion by abdominal tumour/mass
* Ligation during spay

Question 24

What happens if ureteric obstruction is not resolved?

Answer 24

Hydronephrosis if prolonged obstruction
* If relieved within 7 days changes reversible

Question 25

How can ureteric obstruction be treated?

Answer 25

• Surgical removal
• Subcutaneous urethral bypass device

Question 26

How can utereric trauma be identified?

Answer 26

• Blunt trauma history
• Urine in retroperitoneal space
• Electrolyte abnormalities
• Renal function tests may be unaffected

IV urography

Question 27

How is ureteric trauma treated?

Answer 27

• Correct electrolyte/metabolic abnormalities
• Managment depends on site and severity of injury
• Ureteral avulsion at kidney
• Mid-ureteral trauma
• Avulsion at bladder