For an adult with a cryptoglandular low trans‑sphincteric anal fistula involving ≤30 % of the external anal sphincter and no continence problems, is fistulotomy (lay‑open) preferred over LIFT (ligation of the intersphincteric fistula tract)?

Fistulotomy is Preferred for Low Transsphincteric Fistulas ≤30% of External Sphincter

For an adult with a cryptoglandular low trans-sphincteric anal fistula involving ≤30% of the external anal sphincter and no continence problems, fistulotomy is the preferred definitive treatment, achieving near 100% healing rates with a manageable 10-20% risk of minor continence disturbances. 1, 2

Rationale for Fistulotomy as First-Line Treatment

• Fistulotomy provides definitive single-operation cure with healing rates approaching 100% in carefully selected patients with low transsphincteric fistulas. 1, 3

• The procedure is technically simple, effective, and eliminates the need for prolonged seton drainage or multiple repeat procedures that significantly impact quality of life. 1

• For simple low transsphincteric fistulas (≤30% sphincter involvement), patient selection is crucial—fistulotomy can be performed safely when continence is intact and no high-risk features are present. 3

LIFT as Alternative: Lower Success Rates

• LIFT carries a 41-59% failure rate in real-world practice, making it less reliable than fistulotomy for definitive treatment. 1

• While one study reported 82% primary healing with LIFT in low transsphincteric fistulas, the four failures required subsequent fistulotomy anyway, ultimately achieving 100% healing only after sphincter division. 2

• LIFT should be reserved as second-line treatment after seton drainage fails, not as first-line therapy when fistulotomy is feasible. 1

Critical Contraindications to Fistulotomy

Before proceeding with fistulotomy, you must exclude these absolute contraindications:

• Anterior fistulas in female patients should never undergo fistulotomy due to asymmetrical anatomy and short anterior sphincter. 1, 4

• Active proctitis is an absolute contraindication to fistulotomy. 1

• Any history of prior fistulotomy requires sphincter-preserving approaches to prevent catastrophic incontinence. 5, 4

• Crohn's disease patients with low anal fistulas may have simple fistulotomy discussed only after ruling out perianal abscess, but seton placement with antibiotics is generally preferred. 6

Acceptable Risk Profile

• The 10-20% risk of minor continence disturbances from fistulotomy is typically manageable and does not constitute major incontinence. 1, 3

• However, even minor continence disturbances can be functionally devastating for individuals who engage in receptive anal intercourse, requiring aggressive pelvic-floor rehabilitation. 4

• Simple fistulotomy without reconstruction carries this 10-20% continence disturbance risk, but the alternative of treatment failure requiring repeat procedures may be more devastating to quality of life. 1

Alternative Approach: Seton Drainage First

If you prefer a more conservative initial strategy:

• Loose non-cutting seton placement can achieve fistula closure in 13.6-100% of cases and may serve as definitive treatment. 5, 1

• The seton runs through the sphincter complex ending in the internal opening to maintain drainage and prevent abscess recurrence. 5

• Cutting setons should never be used, as they result in 57% incontinence rates from progressive sphincter transection. 5

• If seton drainage fails after adequate trial, then proceed to definitive surgery (fistulotomy if still appropriate, or LIFT if sphincter preservation is now prioritized). 1

Common Pitfalls to Avoid

• Do not perform aggressive probing to define the tract, as this causes iatrogenic complications. 5

• Aggressive dilation should not be performed, as it causes permanent sphincter injury. 5

• If fistula recurs after initial fistulotomy (3-5% incidence), repeat fistulotomy must be avoided—use loose non-cutting seton or LIFT instead. 4

• Do not assume all "low" transsphincteric fistulas are safe for fistulotomy—any transsphincteric fistula involves sphincter muscle and requires careful patient selection. 5

Comparison with Other Techniques

• Mucosal advancement flaps show 62% closure rates for transsphincteric fistulas, significantly better than anal fistula plugs (34% closure), but still inferior to fistulotomy for low fistulas. 7

• The anal fistula plug showed only 54% clinical healing at 12 months versus 55% for surgeon's preference (which included various techniques), with higher costs and uncertain quality-adjusted life-year gains. 8

• For simple intersphincteric anal fistulas, fistulotomy is universally the procedure of choice with healing rates higher than 95%. 3