What is the long‑term risk of developing a new fistula or perianal abscess after a healed low‑grade cryptoglandular anal fistula treated with ligation of intersphincteric fistula tract (LIFT) in a healthy adult?

Long-Term Risk of Recurrence After LIFT Surgery for Healed Anal Fistula

After a successfully healed low-grade cryptoglandular anal fistula treated with LIFT, the risk of developing a new fistula or abscess is 18–27%, with most recurrences occurring between 4 and 8 months post-surgery, though late failures can appear years later. 1

Understanding the True Recurrence Risk

The recurrence data for LIFT has evolved significantly over time:

• Early reports were overly optimistic, quoting recurrence rates as low as 1.6%, but these figures are now recognized as under-reporting due to heterogeneous follow-up periods and inconsistent definitions of success 1
• Contemporary series with adequate follow-up demonstrate recurrence rates of 18–27%, with one prospective cohort documenting a 21% recurrence rate 1
• The median time to failure is approximately 4 months after the procedure, meaning most recurrences declare themselves within the first year 1, 2
• Late recurrences can occur years later, necessitating ongoing surveillance beyond the initial postoperative period 1

Patient-Specific Risk Factors That Increase Recurrence

Certain factors substantially elevate your risk of developing a new fistula or abscess:

High-Risk Factors

• Active smoking at the time of LIFT increases failure risk by approximately 3.2-fold, and this elevated hazard persists throughout follow-up 1, 3
• Active proctitis doubles the hazard of recurrence (HR ≈ 2.0) and may cause late breakdown of an initially healed tract 1, 3
• Complex fistulas (branching or multiple tracts) achieve only 50–53% primary healing, compared with approximately 80% in simple fistulas 1, 3

Factors That Do NOT Increase Risk

• Prior seton drainage does not increase recurrence risk after LIFT 1
• Previous repair attempts do not significantly worsen outcomes 1
• Use of biologic therapy does not negatively impact LIFT success rates 1

Recommended Surveillance Strategy

Active monitoring is essential because recurrence is progressive over time, not limited to immediate postoperative periods. 1, 3 Follow this surveillance algorithm:

Time Point	Assessment	Rationale
Week 1–2	Check for infection signs	Early detection of postoperative sepsis [1]
Week 4	Inspect external opening for healing	Verify tract closure [1]
Week 8	Confirm continued healing progress	Ensure trajectory toward complete closure [1]
Month 4–6	Actively look for early recurrence	Most failures occur in this window [1]
Beyond 6 months	Ongoing surveillance for late recurrences	Capture late failures that may arise years later [1]

• MRI is recommended when clinical uncertainty exists regarding tract obliteration, particularly in complex fistulas; a fibrotic (non-enhancing) tract on MRI predicts no need for further interventions during long-term follow-up 1, 4

Critical Pitfalls to Avoid

During Follow-Up

• Gentle examination is essential; aggressive probing of a failed LIFT can convert a manageable recurrence into a more complex fistula 1
• Do not declare success based on clinical healing alone without radiological confirmation of tract obliteration in complex cases 3

Risk Mitigation

• Smoking cessation is imperative before and after surgery given the 3.2-fold increased failure risk 1, 3
• Active proctitis must be treated before attempting LIFT, as it doubles recurrence risk 1, 3

Comparative Context: Natural History Without Treatment

For perspective on the baseline risk of fistula development:

• After simple abscess drainage without definitive fistula repair, approximately 33% of patients develop a perianal fistula 1
• Younger patients (< 40 years) and non-diabetic individuals are at higher risk for fistula formation after abscess drainage alone 1

What Happens If LIFT Fails

Importantly, failure of LIFT does not worsen fecal continence; in fact, approximately 53% of patients report improvement in continence after the procedure 1

• Overall incontinence rates after LIFT are 1.6%, markedly lower than the 7.8% observed with advancement flap repair 1, 5
• When recurrence occurs, it typically manifests as drainage from the external opening or a palpable tract on examination 1
• Failed LIFT can often be managed with repeat procedures or alternative sphincter-preserving techniques without compromising continence 1