Operation

– Incision and drainage of a perianal abscess.

When should you incise and drain the abscess?

• Drainage within 24 hours.
• Same-day drainage :

– Immune-compromised patients (transplant, dialysis)

– Diabetics  

– Septic patient (fever, tachycardia…)

– Significant cellulitis

Incision and drainage

• Under local or general anesthesia, an incision is made in the swollen and fluctuating part of the abscess. The pus is evacuated and the cavity is flushed with water and Isobetadine. The finger is used to pull down fibrous strands and septa in the abscess cavity.
• The cavity is not closed with stitches as a new infection and abscess would immediately develop in the cavity under the skin.
• The wound heals from the bottom upwards, thus allowing the infected fluid in the cavity to drain out through the open wound.
• At the end of the procedure, a wick is placed in the cavity to keep the wound cavity open and to stem the bleeding through pressure.

How long does the hospitalisation last?

The length of hospitalisation varies from one day to several days, depending on the size of the abscess, soft tissue infection and the patient’s general condition.

Wound care

• On the first day after surgery, the wick is removed from the wound.
• At the surgeon’s request, it may be necessary to have the wick daily replaced by a home nurse.

Smith SR, Newton K, Smith JA, et al. Internal dressings for healing perianal abscess cavities. Cochrane Database Syst Rev 2016;(8):CD011193.pmid:27562822.

It is important to help the infected fluid out of the wound. The skin should not close before the wound is completely filled with granulation tissue from the bottom up, otherwise a new abscess will form.

If no wick is used after surgery, the wound should be kept open by applying gentle traction to the wound edges to allow wound fluid to drain out.

Link to chapter : Wound care

Antibiotics

Antibiotics are not routinely administered after incision and drainage of a perianal abscess.

Antibiotics are prescribed if :

• Major cellulitis (soft tissue infection)
• Diabetes
• Immune-compromised patients (corticosteroids, transplants, dialysis)

Recurrent abscess

7,6% (first 10 days).

• Premature closure of the skin above the abscess.
• Incomplete drainage of the abscess.

Onaca N, Hirshberg A, Adar R. Early reoperation for perirectal abscess: a preventable complication. Dis Colon Rectum 2001;356:1469-73. doi:10.1007/BF02234599 pmid: 11598476. 

Fistula

40-50% of patients develop a fistula within the first 12 months after drainage and incision of the abscess.

• A fistula is an abnormal connection between an internal opening in the anal canal and the skin in the area near the anus (rarely in the rectum). A fistula is usually caused by infection of glands in the anal canal. The glands connected to the anal canal become infected and develop into an abscess. We speak of an anal fistula If after drainage of the abscess, a connection remains open between the anal canal and the incision of the abscess on the skin.
• A fistula is suspected when after healing of the abscess, the scar becomes intermittently painful followed by oozing pus or the presence of an opening that oozes intermittently – A fistula requires a surgical treatment.
• It is not clear whether antibiotics can prevent fistula formation.

Sözener U, Gedik E, Kessaf Aslar A, et al. Does adjuvant antibiotic treatment after drainage of anorectal abscess on prevent development of anal fistulas? A randomized, placebo-controlled, double-blind, multicenter study. Dis Col Rectum 2011;356:923-9.

doi:10.1097/DCR.0b013e31821cc1f9 pmid:21730779. Antibiotic in the use  in prevention  of anal fistulas following incision and drainage of anorectal abscesses: A systematic review  and meta-analysis. Am J Sur. 2019 May 217(5): 910-917)

Normal symptoms

• Anal pain is normal but should subside over time.
• Seepage of serous (yellowish) anal fluid.
• Fluid loss may be bloody but should subside over time.

Abnormal symptoms

Contact your surgeon or GP, or go to the emergency room:

• If pain increases over time.
• If fever does not subside over time.
• If pus volume increases or foul smelling viscous fluid increases.
• If blood loss persists.

If certain symptoms seem abnormal to you contact your doctor.

If this is not possible, you can contact avec your surgeon.

If you are unable to contact your GP or your surgeon, go to the emergency department at St Elizabeth Hospital in Uccle.

Incontinence

• The abscess is incised outside the anal sphincter. The risk of incontinence is extremely low.