For an adult with a low transphincteric anal fistula, normal continence and no Crohn’s disease, should I perform a simple fistulotomy or a ligation of intersphincteric fistula tract (LIFT) procedure?

Fistulotomy is the Preferred Treatment for Low Transphincteric Fistula in Non-Crohn's Patients

For an adult with a low transphincteric anal fistula, normal continence, and no Crohn's disease, you should perform a simple fistulotomy, which achieves near 100% healing rates with an acceptable 10-20% risk of minor continence disturbances. 1

Treatment Algorithm

Step 1: Confirm Eligibility for Fistulotomy

Before proceeding with fistulotomy, you must rule out absolute contraindications:

• Exclude anterior fistula in female patients - these carry catastrophic incontinence risk due to short anterior sphincter and asymmetrical anatomy 1, 2
• Exclude prior fistulotomy history - repeat sphincterotomy is dangerous and requires sphincter-preserving approaches 2
• Exclude active proctitis - macroscopic inflammation contraindicates fistulotomy 1
• Confirm the fistula involves ≤66% of the external sphincter - division limited to the lower two-thirds of the external anal sphincter maintains excellent continence 3

Step 2: Perform Fistulotomy with Technical Enhancements

Fistulotomy is recommended as the definitive treatment for low transphincteric fistulas in carefully selected patients, achieving healing rates approaching 100%. 1 The procedure provides definitive cure in a single operation, avoiding prolonged seton drainage and repeat procedures. 1

Key technical points:

• Perform marsupialization of the opened tract after laying open the fistula, which improves healing rates compared to simple lay-open alone 1
• Avoid aggressive probing to define the tract, as this causes iatrogenic complications 1, 2
• Avoid aggressive dilation, which causes permanent sphincter injury 1, 2

Step 3: Understand the Risk-Benefit Profile

The evidence strongly supports fistulotomy for this clinical scenario:

• Healing rate: Near 100% in appropriately selected patients 1
• Continence risk: 10-20% for minor disturbances, typically manageable 1, 2
• Recurrence rate: 0% at one-year follow-up in prospective studies 3

A prospective 3D-endosonographic study demonstrated that when fistulotomy is limited to the lower two-thirds of the external anal sphincter in patients without risk factors, there is no significant difference in continence scores before and after surgery, with only 13.9% experiencing mild incontinence (all <3/20 on Jorge-Wexner scale). 3

Alternative Approach: LIFT Procedure

LIFT (ligation of intersphincteric fistula tract) can be considered as an alternative sphincter-preserving option, though it has lower success rates. 4 The most recent ECCO guidelines (2024) recommend LIFT as a treatment option for selected patients with complex perianal fistulae, with a clinical success rate of 77% in cryptoglandular fistulas. 4 However, meta-analyses show LIFT has a 41-59% failure rate in real-world practice. 1

LIFT is particularly appropriate when:

• The patient has heightened concern about continence risk
• There are anatomical factors that increase fistulotomy risk
• The patient prefers sphincter preservation despite lower success rates

Common Pitfalls to Avoid

Do not assume all "low" transphincteric fistulas are automatically safe for fistulotomy - any transphincteric fistula involves sphincter muscle and requires careful assessment of the proportion of sphincter involved. 1, 2 The critical threshold is whether the fistula involves more than 66% of the external sphincter. 3

Do not use cutting setons - they result in a 57% incontinence rate from progressive sphincter transection and should never be employed. 1, 2

Do not rush to definitive surgery if there is any uncertainty - initial loose non-cutting seton placement can achieve fistula closure in 13.6-100% of cases and may serve as definitive treatment while allowing inflammation to subside. 1, 2

Seton as Initial Conservative Option

If you prefer a more conservative initial approach, loose non-cutting seton placement is a reasonable first-line treatment that can be definitive. 1, 2 The seton should run through the sphincter complex ending in the internal opening to maintain drainage and prevent abscess recurrence. 1, 2 This approach is particularly valuable when:

• There is any diagnostic uncertainty about fistula complexity
• The patient wants to defer definitive surgery
• You want to allow inflammation to resolve before making final treatment decisions

A prospective study of 247 patients showed that seton placement successfully eradicated the primary fistula tract in 61% of patients, with only 2.4% experiencing fecal incontinence. 5

Evidence Quality and Guideline Hierarchy

The recommendation for fistulotomy is supported by multiple high-quality guidelines. The 2024 ECCO guidelines on Crohn's disease surgery specifically state that fistulotomy should be recommended in carefully selected patients with simple fistulas in the absence of proctitis. 4 While these guidelines focus on Crohn's disease, the surgical principles apply to cryptoglandular fistulas with even better outcomes, as your patient lacks the inflammatory complications of Crohn's disease.

The American College of Surgeons recommends fistulotomy as the definitive treatment of choice for low transsphincteric fistulas, emphasizing the 10-20% continence risk but near 100% healing rates. 1