Loop Drainage Versus Incision and Drainage for Abscesses

Brooke Army Medical Center, The University of Texas Health Science Center at San Antonio, Loyola University, Kaiser Permanente, Stony Brook University

This is a multicenter randomized controlled trial of loop drainage versus traditional incision and drainage in adult patients presenting to the emergency department.

BACKGROUND AND SIGNIFICANCE The usual care in the United States for abscess management is generally incision and drainage. There have been various techniques described for incision and drainage: 1. incision and drainage followed by healing by secondary intention, 2. Incision and drainage followed by primary closure, and 3. Loop drainage (more recently, the topic of this study) with subsequent loop removal and healing by secondary intention. The treatment failure rate for traditional incision and drainage is variable, but can range from 10-30%. Costs associated with treatment failure are between $1,000 and $2,0005. The relatively high failure rate associated with traditional incision and drainage has led to research into less invasive, more effective techniques. In 2010, the loop drainage technique was first described. This technique consists of making 2 small incisions on either end of the abscess cavity followed by pulling a small drain through the incisions and then tying the drain in place. It remains in place and is removed once no further drainage is noticed (usually in 10-14 days). Original studies were primarily done by pediatric surgeons using vessel loops or penrose drains. In 2014, the concept of using the cuff from the bottom of a sterile glove was introduced. This allows for this technique to easily be used with materials found easily in any emergency department. The amount of research done with this technique on adults is limited. To date, only two studies with a total of 109 patients evaluated loop drainage in adults. One of these studies was retrospective and included only 63 patients. The other prospective study was limited in that it included only 46 patients. Given the demonstration of increased clinical cure rate in pediatric populations and the potential for increased clinical cure rates in adults, more study into this topic is worthwhile to determine the optimal approach to adult subcutaneous abscess drainage. STUDY DESCRIPTION This study will be a pilot study and multi-center prospective randomized controlled trial evaluating loop drainage compared to conventional incision and drainage in adults older than 18 who have simple, purulent, cutaneous abscesses deemed amenable to outpatient incision and drainage by the attending clinician. Study participants will be randomized to investigational vs control arm in a 1:1 ratio (Randomization will occur via blocked randomization in blocks of 10). Enrollment will occur primarily when investigators are on shift (convenience sampling). This study will not be blinded, however, observer bias will be reduced by having an investigator blinded to treatment assignment determine the cosmetic healing rate at 90 days. Participants will receive drainage of their abscess (either conventional or loop). For conventional drainage, the wound will be incised with a #11 blade scalpel along the point of maximal fluctuance, approximately 2-3 cm, and then all loculations bluntly dissected with a set of Kelly clamps. After drainage of pus, the wound will be loosely packed with gauze. Afterwards, a dry dressing will be placed and the patient will be instructed to change the external dressing twice daily or every time it becomes saturated. Patients randomized to standard care will be instructed to remove the packing at 48 hours after incision and drainage. Loop drainage will occur via 2 small incisions, approximately 2 cm, with the cuff from the base of a sterile glove pulled through and then tied off3. The patient will be instructed to move this cuff back and forth three times daily and cover it with a dry dressing. Once the abscess drainage procedure is complete, the participant will complete a questionnaire asking about pain during procedure and satisfaction with the procedure. All participants will be discharged with a prescription trimethoprim-sulfamethoxazole (TMP-SMX) 160mg/800mg, two tablets by mouth twice daily for ten days. All participants will be instructed to return to the emergency department and contact the PI if they have any worsening signs of infection. Between 10 and 14 days after the initial procedure, patients will follow up in the emergency department for wound recheck. At this visit, the maximal diameter of both erythema and swelling will be measured, and a questionnaire will be administered regarding wound care satisfaction, repeat medical visits, fevers, and any side effects of either the procedure or antibiotic therapy. Loop participants will have the loop removed at the follow up visit. Participants will be called at 30 days for data collection on abscess recurrences. Patient will be asked to return for a wound recheck and submit a photo of the wound, to assess cosmetic appearance of wound at 90 days.

Loop drainage will occur via 2 small incisions, approximately 2 cm, with the cuff from the base of a sterile glove pulled through and then tied off.

The wound will be incised with a #11 blade scalpel along the point of maximal fluctuance, approximately 2-3 cm, and then all loculations bluntly dissected with a set of Kelly clamps. After drainage of pus, the wound will be loosely packed with gauze.

Defined as healing of the abscess without the need for further clinical intervention (change in antibiotics, repeat drainage, or admission)

Numeric rating scale of 0-10. A rating of 0 indicates no pain. A rating of 10 indicates the worst pain.

Likert scale of 1-5. A rating of 1 indicates poor satisfaction. A rating of 5 indicates the best satisfaction.

Likert scale of 1-5. A rating of 1 indicates poor satisfaction. A rating of 5 indicates the best satisfaction.

Visual analog scale of 1-100 mm. A score of 1 indicates poor cosmetic healing. A score of 100 indicates excellent cosmetic healing.

Inclusion Criteria: Adults age 18 years or older Abscess is considered simple, purulent, and cutaneous Abscess is deemed amenable to outpatient drainage Exclusion Criteria: Inability to speak English Abscess location of breast or face Pilonidal abscesses Concurrent use of chemotherapy or steroids Allergy to sulfa/trimethoprim or lidocaine Inability to provide consent Incarcerated patients Inability to give a valid contact number or email address Presence of multiple abscesses Abscess size less than 2 cm Pregnant patients History of glucose-6-phosphate dehydrogenase deficiency History of Steven Johnson's Syndrome Patients with fever greater than 100.4 Fahrenheit

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