ANORECTAL ABSCESS AND FISTULA IN ANO

5. What is the most common cause of anorectal abscess?

Show answer
Ninety percent result from cryptoglandular infection.

6. What are the four potential anorectal spaces used to classify anorectal abscesses?

Show answer

1. Perianal (area of the anal verge)
2. Ischiorectal (area lateral to the external sphincter muscles, extending from the levator ani muscles to the perineum)
3. Intersphincteric (area between the internal and external sphincter muscles, continuous inferiorly with the perianal space and superiorly with the rectal wall)
4. Supralevator (area superior to the levator ani muscles, inferior to the peritoneum, and lateral to the rectal wall)

7. Define fistula in ano.

Show answer
A fistula is an abnormal communication between any two epithelial-lined surfaces. The internal opening of the fistula in ano involves the anoderm at the dentate line, whereas the external orifice is located at the anal margin.

8. What is the incidence of fistula in ano after appropriate surgical incision and drainage of acute anorectal abscesses?

Show answer
50%.

9. What is the most important factor leading to the successful surgical eradication of anorectal abscesses or fistulas?

Show answer
You must know anorectal anatomy, including the potential spaces (just memorize the answers to questions 4 and 6).

10. What is Goodsall’s rule?

Show answer
The location of the internal opening of an anorectal fistula is based on the position of the external opening. An external opening posterior to a line drawn transversely across the perineum originates from an internal opening in the posterior midline. An external opening, anterior to this line, originates from the nearest anal crypt in a radial direction.

11. What is the most important determinant of successful surgical treatment of fistula in ano?

Show answer
Identification of the internal openings.

12. What is a seton?

Show answer
A seton is a heavy suture placed through the fistulous tract that is then serially tightened, allowing slow, controlled transection of the sphincter. The associated fibrous reaction maintains sphincter integrity. Although associated pain is a limiting factor in its use, the technique can effectively change a high fistula into a low fistula with minimal risk of incontinence.

13. What is the role of fibrin glue in the management of anal fistula?

Show answer
Theoretically, the use of fibrin sealant represents an attractive alternative to the morbidity of operative treatment. However, although preliminary results support a marked decrease in postoperative pain and discomfort, 1-year recurrence rates are often > 50%.