Case Study: Management of a Transsphincteric Perianal Fistula in a 28-Year-Old Male

Case at a Glance

A 28-year-old male presented with a perianal fistula diagnosed via MRI. Awaiting consultation with his primary surgeon, he sought to understand the complexity of his condition, potential surgical options, and the feasibility of delaying treatment for several months due to personal commitments.

Patient's Story

A 28-year-old male presented to a colorectal surgery clinic with a several-month history of intermittent perianal pain, swelling, and a persistent, small opening near the anus that produced occasional purulent discharge. The symptoms were causing significant discomfort and anxiety. He was otherwise healthy with no significant past medical history. After an initial examination, the colorectal surgeon suspected a fistula-in-ano and ordered a pelvic MRI for definitive mapping of the fistula tract before proceeding with a surgical plan. The patient underwent the MRI but his surgeon was subsequently on extended leave, leaving the patient anxious about the results and the path forward. He was particularly concerned about whether the fistula was 'simple' or 'complex' and if surgery could be safely postponed for approximately 3.5 months.

Initial Assessment

Physical examination revealed a single external fistula opening at the 6 o'clock position in the perianal region, approximately 3 cm from the anal verge. The area was non-tender to palpation, with minimal induration and no signs of an acute abscess. Digital rectal examination was unremarkable, and the internal opening was not palpable. Based on these findings, the presumptive diagnosis was fistula-in-ano, and an MRI was ordered to delineate the anatomy of the tract relative to the anal sphincter complex.

The Diagnostic Journey

A pelvic MRI with contrast was performed to evaluate the perianal region. The radiologist's report described a well-defined fistula tract originating from the posterior midline of the anal canal (internal opening at 6 o'clock). The tract was observed to pass through both the internal and external anal sphincter muscles before terminating at the previously identified cutaneous opening. This path is characteristic of a transsphincteric fistula. Importantly, the MRI showed no evidence of a significant associated abscess, suprasphincteric or extrasphincteric extension, or other secondary tracts.

Final Diagnosis

Complex Transsphincteric Fistula-in-Ano (St. James's University Hospital Classification: Grade 4). The fistula was classified as complex due to its transsphincteric course, which involves a significant portion of the sphincter muscle, carrying implications for surgical management and the risk of incontinence.

Treatment Plan

The definitive treatment for a transsphincteric fistula is surgical. Given the patient's concern about delaying the procedure, his case was reviewed. As there were no signs of acute infection or abscess formation, immediate surgical intervention was not medically necessary. The plan was established as follows:

1. Interim Management: The patient was advised to maintain meticulous perianal hygiene to prevent blockage of the external opening and subsequent abscess formation. He was instructed to monitor for signs of worsening infection, such as increased pain, swelling, fever, or changes in drainage, and to seek immediate care if these occurred.
2. Surgical Consultation: A follow-up appointment was scheduled with his colorectal surgeon upon their return. The purpose of this consultation would be to discuss the MRI findings, the nature of a transsphincteric fistula, and the various surgical options.
3. Surgical Options for Discussion: Potential procedures for this type of fistula include a cutting seton, a Ligation of Intersphincteric Fistula Tract (LIFT) procedure, or an advancement flap procedure. The choice would depend on surgeon preference, patient factors, and a detailed discussion of success rates versus risks, particularly regarding sphincter function.
4. Timing: It was determined that a 3-4 month delay was clinically acceptable, provided the condition remained stable.

Outcome and Follow-up

The patient was reassured that his condition, while requiring surgery, was not an emergency. He was able to proceed with his personal plans with the understanding that he needed to remain vigilant for any signs of complication. He is scheduled to see his colorectal surgeon in three weeks to finalize a surgical plan and schedule the procedure for a date approximately three months later. The primary goal of the upcoming surgery will be to eradicate the fistula tract while preserving maximal anal sphincter function.