Incision and drainage of abscesses
Infections with abscess formation are a major problem in many developing countries. Treatment is often delayed or inadequate. Yet there are few surgical procedures that have as dramatic results, in terms of the patient’s satisfaction and confidence in health staff, as the prompt and adequate drainage of an acute abscess.
Incision and drainage of an abscess are indicated if there is evidence of localized pus: throbbing pain; hot, local swelling with tight, shiny skin; and marked tenderness. Fluctuation is the most reliable sign, though it may be absent in a tense or deep abscess. Interference with sleep is a pressing indication for surgery.
Assessment and preoperative management
If in doubt about the diagnosis, confirm the presence of pus by needle aspiration. (An aneurysm may mimic the features of an abscess, but it pulsates and lies in the line of a major vessel.) Measure the patient’s haemoglobin level and test the urine for sugar and protein.
Prepare the skin with antiseptic, and give a local anaesthetic if necessary. Perform a preliminary needle aspiration to confirm the presence of pus if this has not already been done.
Make an incision over the most fluctuant or prominent part of the abscess, in a skin crease if possible. Take a sample of pus for bacteriological examination. Introduce the tip of a pair of sinus or artery forceps into the abscess cavity and open the jaws to improve drainage. Explore the cavity further with a finger to break down all loculi.
It may be necessary to extend the incision or convert it into a cruciate form to deroof the abscess completely, but take care not to open up healthy tissues or tissue planes beyond the abscess wall. The abscess cavity can then be cleaned with swabs soaked in saline or antiseptic solution.
Introduce a large corrugated drain, positioning it well into the depth of the cavity. A counter-incision may be necessary to ensure free and dependent drainage. Fix the drain to the edge of the wound or counter-incision with a stitch of 2/0 thread, and mark it with a safety pin before cutting off the excess drain. Dress the wound with several layers of gauze, the gauze of the deeper layers having been first soaked in antiseptic solution and wrung out. Leave the drain in place for about 2 days, until a track has formed through the tissues or until the drainage is minimal. Alternatively, pack the abscess cavity with a ribbon of petrolatum gauze, leaving one end outside the wound, marked with a safety pin. Control excessive bleeding from the cavity by tight packing with dry gauze; this may be removed after about 12 hours and replaced with a petrolatum gauze pack or a drain.
Too small an incision and failure to provide free drainage are common mistakes in this procedure, leading to chronicity or recurrence of the abscess. The wound edges must not be allowed to close while the abscess cavity remains.
Treatment with antibiotics is unnecessary, unless there is evidence of spreading infection with signs of toxicity or unless the abscess is in a region of crucial importance, such as the hand, ear, or throat.