Procedure-Specific Approach To Minimize Fistulaization of The Perianal Abscess Cavity After Surgical Drainage

Perianal abscess is a common anorectal condition. Most perianal abscesses are due to infection of the glandular crypts of the rectum and anus caused by non-specific obstruction. A small percentage of cases, around 10%, can be attributed to alternative causes such as Crohn's disease, trauma, human immunodeficiency virus, sexually transmitted diseases, radiation therapy, or foreign bodies.

Perianal abscesses are considered one of the most common colorectal pathologies with an estimated annual incidence of around 20,000 people in Egypt. Perianal abscesses are more common in males as compared to females and more in younger males than older. Also, there is an increased risk of anorectal abscess in conditions such as diabetes, and obesity.

Perianal pain is the most common presentation of perianal abscesses, which may increase with defecation, movement, sitting or coughing. Supra-levator abscesses may present with lower back pain or a dull ache in the pelvic region. Patients may also report fever, malaise, rectal drainage, erythema of surrounding skin and possibly urinary retention. The severity of pain can sometimes prevent the clinician from performing a digital rectal examination or anoscopic examination, therefore if the diagnosis is in doubt, an examination under general anaesthesia should be performed.

Anorectal abscesses can spread into the ischiorectal fossa. They can lead to a horse-shoe-shaped collection or track up towards and through the levator musculature, making management more challenging. Perianal fistulae are a common complication of peri-anal abscesses. Fistulae can be classified according to their tract location in relation to the internal and external sphincters as transphincteric fistula, high intersphincteric fistula, suprasphincteric fistula or extra sphincteric fistula.

In the presence of a perianal fistula, imaging modalities such as CT scans help diagnose intraabdominal pathology such as Crohn's disease and detecting air within the fistulous tract and the abscess cavity. However, MRI is the investigation of choice in evaluating secondary extensions from the fistulous tract and differentiating it from nearby pelvic soft tissue structures.

The management of perianal abscesses is incision and drainage. Without adequately eliminating the source of infection, antibiotics will be ineffective. Minimizing the patient's pain, protecting anal sphincter function and reducing the recurrence of anal fistulae is as important as curing the abscess. Packing at the time of abscess drainage, which requires multiple dressing changes per week for several weeks, can be helpful in providing hemostasis of the inflamed, hypervascular abscess cavity.

However, about 40% of patients with perianal abscess subsequently develop fistula after management. Packing is frequently accompanied by postoperative pain and discomfort, slow wound healing, and increased financial burden yet lower rate of incidence of fistula as demonstrated in Pearce study. Also, there is lack of information comparing postoperative outcomes in managing the perianal abscess cavity with packing and with no packing.