Anal Fistula

Question 1

What is an anorectal fistula?

Answer 1

Abscess drains into rectum

Question 2

Risk factors for an anorectal fistula

Answer 2

Inflammatory bowel disease
Systemic diseases
History of trauma
Recurrent abscesses

Question 3

Clinical features of anorectal fistulas

Answer 3

Recurrent perianal abscesses
Discharge from rectum
Defecation pain

Question 4

What is Goodsall’s rule?

Answer 4

Predict trajectory of fistula tract depending on location of external opening

Posterior to anal line
- curved fistula tract

Anterior to anal line
- straight fistula tract

Question 5

Investigations for a suspected anorectal fistula

Answer 5

Proctoscopy

MRI - if complex

Question 6

What is a simple anorectal fistula?

Answer 6

Minimal or no involvement of external sphincter

Question 7

What is a complex anorectal fistula?

Answer 7

Involves >30% of external sphincter

Question 8

What is Park’s classification system?

Answer 8

Divides anorectal fistulas into four distinct types

• inter-sphincteric (most common)
• trans-sphincteric
• extra - sphinicteric
• supra-sphincteric (least common)

Question 9

Management of a simple anorectal fistula

Answer 9

Fistulotomy

• insert probe
• lay open the tract
• allow to heal by secondary intention

FIbrin plug
- close tract

Question 10

Management of a complex anorectal fistula

Answer 10

Staged fistulotomy

• tie with seton
• tighten seton
• opens tract