Journal Logo


InFocus: Loop Drainage for Cutaneous Abscess

Roberts, James R. MD

Author Information
doi: 10.1097/01.EEM.0000427054.35105.ff
    See One, Do One
    See One, Do One:
    See One, Do One. Watch a video from Dr. Robert Orman's showing how to do an incision and loop drainage in EMN's iPad app, available for free in the iTunes app store or at

    A cutaneous abscess is a common denizen of any ED, and hardly a shift goes by where the EP, PA, NP, or resident is not called upon to ameliorate this condition. An abscess is rarely a diagnostic dilemma, and it has been a universal axiom since the time of Hippocrates that an abscess will not resolve unless the pus is evacuated. Traditionally, the cure has been a generous skin incision, drainage, perhaps some local manipulation of the cavity, and packing, with follow-up for packing change or removal, or a check for resolution.

    Little has changed over the years, but recently a nifty new drainage technique has been espoused, the issue of antibiotics for the treatment of the MRSA-bearing abscess has been clarified, and the routine use of time-honored packing has been questioned.

    This month's column will begin a series of discussions on the practical ED issues involved with treating a cutaneous abscess. The first iteration describes a very attractive, attention-deserving, poorly disseminated, yet simple and minimally invasive technique that may be as successful as more complex traditional treatment, even for an abscess harboring MRSA.

    Minimally Invasive Technique in Treatment of Complex Subcutaneous Abscesses in Children

    Ladd AP, et al

    J Pediatric Surg


    A cutaneous abscess in a child is often a major medical issue for the patient and clinician. It is perplexing enough for an adult, but can be a horrific experience for a child. The escalating incidence of MRSA infections has created a surge in the number of abscesses requiring surgical drainage. Abscesses in children presenting to pediatric referral centers have increased 10-fold over the past five years, and MRSA is often the culprit.

    Silicone vessel loops for use in the loop drainage technique
    Silicone vessel loops for use in the loop drainage technique:
    Silicone vessel loops for use in the loop drainage technique.

    Successful treatment for even a compliant adult usually requires more than one visit, is uncomfortable and annoying, and often the universally accepted skin incision leaves a rather nasty scar. Continued packing to maintain a well debrided and clean wound, supposedly to promote healing and closure, is the classic intervention.

    The authors wanted to find a more humane and patient-friendly yet equally effective technique for complicated abscesses in children, and what they describe as a “novel technique” is much less invasive, minimizes morbidity, and greatly simplifies subsequent wound care. The incision in this technique, which is called incision and loop drainage, is vastly different from the commonly advocated deep-skin incision that transverses the entire length of the abscess cavity. Once thought to be medical heresy, the stab incision has been revived, but this minimal opening is kept patent by a simple string-like loop device that allows continued drainage. The older clinician might remember when surgeons used to tie rubber bands into the abscess cavity with a similar intent.

    The authors report their experience with loop drainage of abscesses in 128 children treated over 14 months. The median patient age was about 2 years old, but ranged from five weeks to 18 years. MRSA was cultured in about 75 percent of the abscesses. Most patients (70%) required a single loop, but about a third required additional loops (up to four) to be placed during the initial procedure. The loop drains were kept in place for about 10 days, and no local recurrence was found during the 14-month follow-up, and no morbidity or progression to systemic illness occurred.

    Abscesses of the neck, those with lymphangitis, or pilonidal or perianal abscesses were not treated with this technique in the beginning. These were not small lesions, and required extensive drainage. Most children required a hospital stay. Typically the abscess was greater than 5 cm in diameter. Initially, the OR and general anesthesia were used for loop placement, but as the surgeons became more familiar with the technique, more patients were handled in the observation unit or as outpatients. Others have subsequently used the technique with local anesthesia for any abscess location and as an outpatient procedure.

    These authors utilized a technique that included an initial “stab incision” at the “site of origin” of the abscess. This was either the midpoint of the abscess or an area where spontaneous drainage had occurred. A hemostat was placed through the first incision and into the abscess cavity, using the instrument to probe the cavity, to break up loculations, and to determine the margin of the abscess. Another stab incision was made at the distal site of the abscess identified by hemostat probing. The hemostat transversed the entire abscess cavity, and the tip protruded through the distal skin to grasp and pull the loop through and out of the abscess. A silicone vessel loop or a quarter-inch Penrose drain was threaded through the two incisions. The loop ends were then loosely tied on the skin. The purpose of the loop was to provide continuous drainage through the 4–5 mm stab incisions without incising the entire length of the cavity. Up to four similar loops were used in large abscesses. The cavity was irrigated with saline or half-strength peroxide at the discretion of the operating surgeon. The ends of the loops were only loosely tied to avoid skin tension, and a dry dressing was applied. Warm soaks were advocated. When the cellulitis, induration, and wound drainage ceased, the loop drain was removed. Removal occurred at an average of nine days (range 5–29).

    The use of antibiotics was not standardized, but they were occasionally given for a short period, often for only 24 hours until fever and cellulitis resolved. Either vancomycin or clindamycin were chosen. Trimethoprim/sulfamethoxazole was used for outpatient therapy.

    The authors concluded that this technique is applicable to all abscesses, including MRSA infections. The procedure negated the need for multiple repeat visits, wound packing, or healing by secondary intention with significant scarring. Obviating the need for packing change was a major perceived benefit. This technique allowed for adequate drainage and the ability to break up loculations and debride necrotic tissue. The remarkable success of the technique was attributed to the fact that it allowed for ongoing drainage facilitated by the indwelling loop that prevented premature skin closure. Importantly, even large abscesses were successfully treated with this technique, and many had expansive cellulitis.

    Comment: Imagine curing a nasty abscess with only two small incisions, no packing changes, only one postoperative visit, and, when healed, painless removal of a small string, leaving only two miniscule scars. This exactly describes the rather unique loop drainage therapy that is applicable to many abscesses drained in the ED. The abscesses in this study were complex, often done under general anesthesia, and were the kind that most emergency physicians would punt to the OR or attack with a large open incision and recurrent packing. Sounds too good to be true: tiny holes made for the surgical loop were cosmetically desirable; painful wound packing was eliminated (a blessing, indeed, for all); repeat visits to a busy ED were eliminated; and all infections did well. Note that the drain was kept in place for a time period based on clinical observation.

    The following study also supports this technique for almost any abscess that is fair game for the ED or fast track.

    Incision and Loop Drainage: A Minimally Invasive Technique for Subcutaneous Abscess Management in Children

    Tsoraides SS, et al

    J Pediatric Surg


    This article appeared in the same issue of the Journal of Pediatric Surgery as the prior article by Ladd et al. It was from different institutions, but also only included children. These authors have used loop drainage for subcutaneous abscesses for a number of years, and their retrospective study evaluated patients treated from 2005 to 2007. These authors used only a silicone vessel loop drain, not a Penrose drain. The images in this article are informative, but not as helpful as videos. If you are contemplating adopting the procedure (which I strongly recommend), you have to watch the videos by Dr. Veronica Bonales on EMRA's website (see FastLinks) and especially the one on the ERCAST website by video aficionado, Dr. Rob Orman. (Available in EMN's iPad app and on; see FastLinks.)

    Half of the 115 patients who had the drainage procedure had MRSA abscesses. There were five pilonidal abscesses, and it appears that abscesses in all areas were treated by this technique, including labial and neck lesions. These authors are positive about this technique, recommend it as the procedure of choice for cutaneous abscesses in children, and consider it standard of care at their facility. These children were also all treated in the OR under general anesthesia, but why this was required was not elucidated. They emphasize the difficulty in treating abscesses in frightened and combative children. (I suggest they try ketamine.)

    These surgeons placed their two puncture incisions at the margins of the abscess cavity, rather then entering at the origin or middle of the abscess. Abscesses were probed and pus was drained by manual pressure. A large bore plastic IV catheter was inserted into the abscess cavity to irrigate it with warm saline. A 60 ml irrigating syringe may also be used. It was emphasized that tension not be used on the tied ends of the drainage loop. The drains were left in place for seven to 10 days. The loop technique failed in five percent of cases, and four of six patients received another loop technique and were cured. It is informative that the authors recommend the minimally invasive loop drainage technique as the treatment of choice for subcutaneous abscesses in children.

    Comment: If you have not used this technique, you should give it a try. It may be counterintuitive that two small puncture wounds at the margins of an abscess will result in healing comparable with wide open incision and repeated packing, but this has certainly been case in the experience of these authors and in my limited experience. I have been using the loop drainage technique for about six months, and it has been incorporated by most of our physicians, PAs, and NPs in the fast track. It is a nifty intervention that should be considered by all clinicians. Patients love it. I love it. It is minimally uncomfortable, very patient-friendly, and negates the need for any packing changes. Daily showering is not only possible but recommended. Most importantly, the end result is two tiny puncture scars, not a large obvious scar that has healed by secondary intent.

    It has been my experience that patients universally prefer this over formal I&D when they have recurrent infections. Hidradenitis is the perfect example where patients can compare the two procedures. I have not yet used it for a Bartholin gland abscess over a Word catheter, but a similar technique has been described at Jacoby Hospital. (J Emerg Med 2009;36[4]:388; Am J Emerg Med 2005;23[3]:414.) I will try the loop technique on the next Bartholin abscess that finds its way to my ED.

    The loop technique can be done under local anesthesia in adults, likely also in adequately sedated children. One should probably anesthetize the abscess as one would for formal I&D. I prefer placing a 25-gauge needle on the dome of the abscess, just underneath the epidermis, to provide anesthesia for the entire abscess with a single needlestick. This is rather tricky and requires some practice because the skin of the abscess is often thin, and the needle must be held in place while injecting. Sometime the needle is dislodged from the pressure of the injection. Of course, a field block would also be appropriate, but I find the majority of abscesses can obtain great anesthesia with a single needle puncture and the slow injection of the local anesthetic as it visibly spreads, with obvious blanching, to the appropriate margins of the abscess.

    We have used the larger silicone vessel loop, readily available from the OR and now stocked in our ED. It's a bright orange, easy to work with, and with proper attention to detail, stays adequately tied for seven to 10 days. It must be tied loosely, with no skin tension. Irrigating the abscess cavity is personal preference; I do not always employ irrigation. It seems reasonable, but I have not seen any evidence that irrigation helps, and it is quite messy. Maybe it's a good idea with this technique because the drainage holes are smaller.

    Patients do not need to come back for a two- to three-day wound check, and there is no packing to change. They can shower with the vessel loop in place and merely cover it with a dry gauze because drainage will continue. Some recommend that the patient slightly rotate the loop twice a day to maintain drainage. It usually requires seven to 10 days for resolution, and a single follow-up is all that is required at approximately 10 days postop for a compliant patient. Obviously, if the patient is not healing well or the loop becomes untied, an early repeat visit is warranted.

    The surgeons in these reports used antibiotics, and one might intuit that antibiotics would be more useful because drainage is not as wide, but this has never been proven. Opting for antibiotics follows the same logic as applied to traditional I&D in my experience. Our physicians do not routinely provide antibiotic coverage for most abscess patients, even with the loop technique. Those with diabetes, immunocompromise, very large abscesses, or with extensive cellulitis still garner antibiotics by most clinicians, but supportive data are nonexistent. It makes sense when giving an antibiotic to give one that covers MRSA.

    This is an easy technique to master, and once you use it, you will likely be a convert, if not a proselytizing apostle. Most will not believe how barbaric, in comparison, were your prior I&D procedures. Your patient will, however, quickly voice his preference.

    Click and Connect!Access the links in EMN by reading this issue on our website or in our iPad app, both available



    Reader Feedback: Readers are invited to ask specific questions and offer personal experiences, comments, or observations on InFocus topics. Literature references are appreciated. Pertinent responses will be published in a future issue. Please send comments to [email protected]. Dr. Roberts requests feedback on this month's column, especially personal experiences with successes, failures, and technique.

    © 2013 Lippincott Williams & Wilkins, Inc.