Seton Placement for Infected Anal Gland
For an infected anal gland (anorectal abscess), perform immediate incision and drainage, and if a fistula involving sphincter muscle is identified, place a loose draining seton rather than performing primary fistulotomy to prevent fecal incontinence. 1
Initial Surgical Management
The primary treatment is surgical drainage of the abscess, not antibiotics alone. 1
- Perform incision and drainage as soon as the diagnosis is made, with timing based on severity of sepsis 1
- In fit, immunocompetent patients with small perianal abscesses without systemic sepsis, outpatient management may be considered 1
- For patients with systemic signs of infection or sepsis, request complete blood count, serum creatinine, and inflammatory markers (C-reactive protein, procalcitonin, lactates) to assess severity 1
- Check serum glucose, hemoglobin A1c, and urine ketones to identify undetected diabetes mellitus 1
Fistula Management During Abscess Drainage
When a fistula is identified at the time of abscess drainage, the approach depends on sphincter involvement:
Low Fistulas (Not Involving Sphincter)
- Perform primary fistulotomy only for subcutaneous fistulas that do not involve any sphincter muscle 1
- This prevents recurrence without risking incontinence 1
High Fistulas (Involving Sphincter Muscle)
- Place a loose draining seton instead of performing fistulotomy 1
- The loose seton establishes drainage, prevents abscess recurrence, and preserves sphincter function 2
- This allows time for inflammation to resolve before considering definitive sphincter-sparing procedures 2
No Obvious Fistula
- Do not probe to search for a possible fistula, as this risks iatrogenic complications 1
Antibiotic Therapy Indications
Antibiotics are adjunctive, not primary treatment. 1
Add antibiotics only when:
- Systemic signs of sepsis are present 1
- Surrounding soft tissue infection/cellulitis extends beyond the abscess 1
- Patient is immunocompromised 1
- Source control is incomplete 1
When antibiotics are indicated, use empiric broad-spectrum coverage for gram-positive, gram-negative, and anaerobic bacteria. 1
Critical Pitfalls to Avoid
- Never rely on antibiotics alone without surgical drainage - this leads to treatment failure and progression of infection 1, 3
- Avoid primary fistulotomy for high fistulas involving sphincter muscle - this significantly increases risk of fecal incontinence 1, 4, 5
- Do not probe for occult fistulas during acute abscess drainage - this creates iatrogenic fistula tracts 1
- Avoid inadequate drainage - insufficient drainage leads to recurrence rates as high as 44% 2
Seton Technique Considerations
- Insert at least two setons through the fistula tract: one tied loosely for drainage, and if using a cutting seton approach, one tied more tightly 6
- Most simple cases can be performed in clinic without anesthesia 6
- Median healing time with seton drainage is approximately 9 weeks 6
- Setons reduce recurrence by 83% compared to drainage alone, though there is a tendency toward higher flatus incontinence risk with any sphincter-cutting procedure 4