Adjunctive Antibiotics Do Not Reduce Fistula Formation After Anorectal Abscess Drainage

Overview

This retrospective cohort study of 770 adults undergoing incision and drainage (I and D) for cryptoglandular anorectal abscesses found that adjuvant antibiotic therapy did not reduce the 12-month fistula formation rate. Fistula development was associated with abscess location and patient age, while diabetes mellitus was inversely associated.

Background

Anorectal abscesses are commonly managed by incision and drainage, but subsequent fistula formation remains a clinical challenge. The role of adjunctive antibiotic therapy in preventing fistula development after abscess drainage is controversial. Understanding factors influencing fistula formation can guide postoperative management and improve patient outcomes.

Data Highlights

Key Findings

• Adjuvant antibiotic therapy for ≥7 days post-I and D did not reduce fistula formation at 12 months.
• The overall fistula formation rate was low at 6.8% among the cohort.
• Fistula development was significantly associated with abscess location and age over 40 years.
• Diabetes mellitus was negatively associated with fistula formation.
• No fistulas developed in patients whose abscess cultures grew skin-derived microorganisms.

Clinical Implications

Routine use of adjunctive antibiotics after incision and drainage of cryptoglandular anorectal abscesses may not be warranted solely to prevent fistula formation. Clinicians should consider abscess location and patient age as risk factors for fistula development. The inverse association with diabetes mellitus and absence of fistula in skin-derived infections may inform individualized patient management.

Conclusion

Adjuvant antibiotic therapy following anorectal abscess drainage does not reduce fistula formation risk. Patient and abscess characteristics remain key determinants of fistula development.

References

1. Gaertner WB et al. 2022 -- The American Society of Colon and Rectal Surgeons clinical practice guidelines for anorectal abscess and fistula
2. Parks AG et al. 1976 -- A classification of fistula-in-ano
3. Abcarian H. 2011 -- Anorectal infection: abscess-fistula
4. Polaino Moreno V et al. 2024 -- Efficacy of amoxicillin/clavulanic acid after surgical drainage of perianal abscess
5. Sözener U et al. 2011 -- Does adjuvant antibiotic treatment after drainage prevent anal fistulas?