What is the best treatment approach for a patient with a 1.2 cm anal fistula, presenting with purulent soiling for 2 months, and an internal opening at the mid-posterior region, as shown on MRI?

From the Guidelines

The most appropriate treatment for this patient with a suspected intersphincteric fistula is option 1: cutting seton placement, as it allows for controlled drainage and minimizes the risk of fecal incontinence. Based on the clinical presentation of a patient with purulent soiling for 2 months, a suspicious opening at the midposterior region, mucosal bulge without external opening on scope examination, and an MRI showing a 1.2 cm collection just inside the levator plate, this approach is most suitable. The cutting seton would be placed through the internal opening, through the fistula tract, and out through the perianal skin, then secured with a knot, as recommended by the ECCO guidelines on therapeutics in Crohn's disease: surgical treatment 1.

Some key points to consider in this case include:

• The patient's symptoms and examination findings suggest a complex fistula that requires careful management to prevent recurrence and promote healing.
• The MRI findings indicate a collection just inside the levator plate, which suggests a high intersphincteric fistula that may be challenging to treat with other methods.
• The cutting seton approach allows for controlled, gradual division of the involved sphincter muscle while promoting drainage and preventing recurrent abscess formation.
• Fibrin glue (option 2) has high failure rates for complex fistulas, and laying open from within (option 3) risks significant sphincter damage and incontinence given the high location 1.
• The LIFT procedure (option 4) would be challenging without a clearly identifiable external opening and may not be suitable for a fistula at the levator plate level.
• The ECCO guidelines suggest that fistula treatment should start with insertion of a seton followed by medical treatment, and that surgical closure can be considered in the absence of proctitis 1.
• A recent study also suggests that advancement flap can be a treatment option for selected patients with complex perianal fistulae in the absence of proctitis, but this may not be suitable for this patient given the high location of the fistula 1.

Overall, the cutting seton approach balances the need for definitive treatment while minimizing the risk of fecal incontinence in this complex case.

From the Research

Treatment Options for Anal Fistula

The patient presents with a complex anal fistula, as evidenced by the MRI showing a collection 1.2 cm just inside the levator plate and the presence of a mucosal bulge with no external opening. The following treatment options are considered:

• Cutting Seton: This method involves the placement of a seton to gradually divide the sphincter muscle, allowing the fistula to heal 2, 3, 4, 5. However, studies have shown that this method carries a risk of minor control defects and incontinence, particularly for high transsphincteric fistulas 4, 5.
• Fibrin Glue: This method involves the injection of fibrin glue into the fistula tract to promote healing. However, studies have shown that this method has a lower success rate compared to other treatments, such as the anal fistula plug and advancement flap closure 6.
• Lay Open from Within: This method involves surgically opening the fistula tract from the inside, allowing it to heal from the bottom up.
• Lift Procedure: This method involves surgically lifting the fistula tract and closing it from the outside.

Efficacy of Treatment Options

The efficacy of these treatment options varies, with some studies showing better outcomes for certain methods. For example, the anal fistula plug and advancement flap closure have been shown to have similar healing rates and are superior to seton placement and fibrin glue 6. The cutting seton method has been shown to be effective for complex fistulas, but carries a risk of incontinence, particularly for high transsphincteric fistulas 4, 5.

Considerations for Treatment

When considering treatment options for this patient, the following factors should be taken into account:

• The location and complexity of the fistula
• The patient's overall health and medical history
• The potential risks and benefits of each treatment option
• The patient's preferences and quality of life considerations Studies have shown that the cutting seton method can be effective for complex fistulas, but may not be suitable for all patients, particularly those with high transsphincteric fistulas or previous peri-anal surgery 5. The fibrin glue method has been shown to have a lower success rate, but may still be considered for certain patients 6.