Rectovaginal fistulas

Question 1

How do you confirm a rectovaginal fistula?

Answer 1

Instill methylene blue into rectum and observe if either dye or air bubbles pass into the vagina. Or CT scan w/ GI contrast.

Question 2

What is the differential diagnosis for leaking/vaginal discharge?

Answer 2

vaginal bleeding, vaginitis, retained foreign body, surgical complication, rectovaginal fistula.

Question 3

Best test to evaluate for fecal incontinence?

Answer 3

accidental passing of solid or liquid stools from the rectum

Endoanal ultrasound=gold standard. Also methylene blue, fistulogram/barium enema, stool culture for O&P.

Question 4

How would you counsel for surgical consent for sphincter disruption?

Answer 4

Immediate surgical risks (anesthesia, infection, bleeding)
High risk (at least 50%) for recurrent breakdown despite adequate repair
Persistent fecal incontinence
Rectovaginal fistula
Urinary incontinence (from pudendal neuropathy)
Defecatory dysfunction and/or dyspareunia from too tight repair.

Question 5

How would you repair a sphincter disruption (i.e. from bad 3rd degree)

Answer 5

Prepare tissue, eradicate infection
Return to normal estrogen status
Bowel prep
Antibiotics
Sphincteroplasty

Question 6

How would you repair a simple fistula (does not involve the anal sphincter complex)?

Answer 6

Repair when there is no inflammation or infection.
Make elliptical incision around the fistula tract. Place non-dominant index finger into rectum to demonstrate fistula. Mobilize posterior vaginal wall off of the anterior rectal wall. Excise fistula tract and adjacent scar tissue. Close rectal mucosa w/ delayed absorbable suture (vicryl). Second layer of closure inverts first layer. Use third layer of closure. Close vaginal mucosa.

Question 7

How do you evaluate patient with passage of stool in vagina on physical exam after forceps/3rd degree repair?

Answer 7

1. Integrity of posterior vaginal wall and perineal body: scarring or retraction or posterior wall? is perineal body absent?
2. Digital rectal exam
   - resting tone vs. squeeze tone.
   - is sphincter anatomically disrupted? loss of normal puckering around the anus anteriorly (dovetail sign)
3. gross evaluation of pudendal nerve w/ bulbocarvenosis wink: tests for spinal injury: pricking the skin of the perianal region and watching for the external anal sphincter to contract. The absence of this contraction signifies a lesion in the sacral region.
4. Vaginal mucosa
   - assess estrogen status
   - inspect for obvious fistula
   - malodorous discharge/fecal material in vagina.