Management of Anorectal Fistula Sites

Current Practice and Evidence

Common practice is to place an internal dressing (pack) into the cavity following incision and drainage of an anorectal abscess for hemostasis and to prevent premature closure of the skin 5
Packing is traditionally changed regularly until the cavity heals 1, 5
Some clinicians alternatively place a catheter or drain into the abscess cavity, which drains into an external dressing and is left in place until drainage stops 1, 3

Despite being commonly performed, the role of wound packing after anorectal abscess drainage remains unproven 1, 4
Proponents of packing suggest it may reduce healing time and decrease recurrence rates 2, 5
However, packing is associated with increased pain during dressing changes 1, 3 and higher healthcare expenses due to prolonged use 2, 4

A Cochrane review concluded that it's "unclear whether using internal dressings (packing) for the healing of perianal abscess cavities influences time to healing, wound pain, development of fistulae, abscess recurrence, or other outcomes" 1, 5
A multi-center observational study found that packing is costly and painful without providing clear benefits to the healing process 3, 4

For anorectal abscesses with an obvious fistula, if the fistula is low and doesn't involve sphincter muscle (subcutaneous fistula), perform fistulotomy at the time of abscess drainage 2
If the fistula involves any sphincter muscle, place a loose draining seton rather than performing immediate fistulotomy to prevent incontinence 3
Avoid probing to search for a fistula if one is not obvious, as this may cause iatrogenic complications 4

High recurrence rates after drainage (up to 44%) emphasize the need for complete and accurate drainage of the abscess 5
Risk factors for recurrence include inadequate drainage, loculations, horseshoe-type abscess, and delayed time from disease onset to incision 5
A third of perianal abscesses may develop a fistula-in-ano, increasing the risk of abscess recurrence requiring repeat surgical drainage 3, 4
For complex fistulas or those in immunocompromised patients, more specialized approaches may be needed 6