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Date: December 10th, 2020

Reference: Ladde et al. A Randomized Controlled Trial of Novel Loop Drainage Technique Versus Drainage and Packing in the Treatment of Skin Abscesses. AEM December 2020

Guest Skeptic: Dr. Kirsty Challen (@KirstyChallen) is a Consultant in Emergency Medicine and Emergency Medicine Research Lead at Lancashire Teaching Hospitals Trust (North West England). She is Chair of the Royal College of Emergency Medicine Women in Emergency Medicine group and involved with the RCEM Public Health and Informatics groups. Kirsty is also the creator of the wonderful infographics called #PaperinaPic.

Case: A 52-year-old previously healthy woman presents to your emergency department (ED) with an abscess on her left forearm. She is systemically well and there is no sign of tracking, so you decide to perform incision and drainage in the ED. When you ask your nursing colleague to set up the equipment, he wants to know if you will be using standard packing or a vessel loop drainage technique.

Background: We have covered the issue of abscesses multiple times on the SGEM. Way back in 2012 we looked at packing after incision and drainage (I&D) on SGEM#13 and concluded routine packing might not be necessary.

Another topic covered was whether irrigating after I&D was superior to not irrigating (SGEM#156). The bottom line from that critical appraisal was that irrigation is probably not necessary.

Chip Lange (PA)

The use of antibiotics after I&D is another treatment modality that has been debated over the years. Chip Lange and I interviewed Dr. David Talan about his very good NEJM randomized control trial on SGEM#164. The bottom line was that the addition of TMP/SMX to the treatment of uncomplicated cutaneous abscesses represents an opportunity for shared decision-making.

One issue that has not been covered yet is the loop technique. This is when one or multiple vessel loops are put through the abscess cavity. This is done by making a couple of small incisions. An advantage to this technique over packing (which is not necessary) is that the Vessel loops do not need to be changed or replaced.

Clinical Question: In uncomplicated abscesses drained in the ED, does the LOOP technique reduce treatment failure?

Reference: Ladde et al. A Randomized Controlled Trial of Novel Loop Drainage Technique Versus Drainage and Packing in the Treatment of Skin Abscesses. AEM December 2020

  • Population: Patients of any age undergoing ED drainage of skin abscesses
    • Exclusions: Patient with abscess located on hand, foot, or face or if they required admission and/or operative intervention.
  • Intervention: LOOP technique where a vessel tie is left in situ
  • Comparison: Standard packing with sterile ribbon gauze
  • Outcome:
    • Primary Outcome: Treatment failure (need for a further procedure, IV antibiotics or operative intervention), assessed at 36 hours.
    • Secondary Outcomes: Ease of procedure, pain at the time of treatment, ease of care at 36 hours, pain at 36 hours.

Dr. Ladde

This is an SGEMHOP episode which means we have the lead author on the show. Dr. Ladde is in an active academic emergency physician working at Orlando Regional Medical Center serving as core faculty and Senior Associate Program Director. Jay also has the rank Professor of Emergency Medicine for University of Central Florida College of Medicine.

Authors’ Conclusions: “The LOOP and packing techniques had similar failure rates for treatment of subcutaneous abscesses in adults, but the LOOP technique had significantly fewer failures in children. Overall, pain and patient satisfaction were significantly better in patients treated using the LOOP technique.”

Quality Checklist for Randomized Clinical Trials:

  1. The study population included or focused on those in the emergency department. Yes
  2. The patients were adequately randomized. Yes
  3. The randomization process was concealed. Yes
  4. The patients were analyzed in the groups to which they were randomized. Unsure
  5. The study patients were recruited consecutively (i.e. no selection bias). No
  6. The patients in both groups were similar with respect to prognostic factors. Yes
  7. All participants (patients, clinicians, outcome assessors) were unaware of group allocation.
  8. All groups were treated equally except for the intervention. Yes
  9. Follow-up was complete (i.e. at least 80% for both groups). Yes
  10. All patient-important outcomes were considered. Yes
  11. The treatment effect was large enough and precise enough to be clinically significant. No

Key Results: They recruited 256 participants into the trial with 90% (196) having outcome data. The mean age was 22 years, 71% were thought to also have cellulitis and 83% (213/256) received antibiotics at discharge. More than 80% of those prescribed antibiotics were given the combination of cephalexin and TMX-SMP.

No statistical difference in treatment failure between loop technique and packing.

  • Primary Outcome: Treatment failure
    • 20% (95% CI 12-28%) in packing group vs. 13% (6-20%) LOOP group; p=0.25.
  • Secondary Outcomes: 
    • Treatment Failure in Children: 21% (8-34%) in packing group vs 0% LOOP group p=0.002.
    • Ease and pain of procedure were the same, but ease of care and pain over 36 hours and patient satisfaction at 10 days were improved in the LOOP group

We have five nerdy questions for Jay. Listen to the podcast on iTunes to hear his responses.

1) Old Data: This study was conducted from March 14, 2009, until April 10, 2010. Why delay and do you think the results are still valid today?

2) Convenience Sample: You only recruited when the research team was available. This is a common limitation seen in EM research. Did you manage to cover the whole working week adequately?

3) Children: You did a subgroup analysis of children. This was not pre-planned and should be considered hypothesis generating. Why do you think they appear to have responded  differently and have you tried to confirm this result?

4) Blinding: We appreciate it can be difficult to blinding the clinician and patient to treatment allocation. However, would it have been possible to blind the outcome assessors? The clinician could have removed the packing or loop and then a research assistant could have assessed the outcome blinded to treatment modality.

5) Comparison Group: You compared this to ribbon packing. We have evidence that this is not necessary (SGEM#13). Have you considered repeating the trial and investigating the LOOP technique and comparing it to not packing the abscess?

Comment on Authors’ Conclusion Compared to SGEM Conclusion: We agree with the authors’ conclusions about failure rates in adults, and pain and satisfaction overall. We are more cautious about the reduced failure rate in children and think this has room for further exploration.

SGEM Bottom Line: Consider putting in a vessel LOOP on your next uncomplicated abscess.

Case Resolution: You ask the nurse to set up for the LOOP technique and the patient leaves after the procedure with follow up planned.

Dr. Kirsty Challen

Clinical Application: Using the LOOP technique can result in less pain and easier care for the patient in the 36 hours following I&D.

What Do I Tell My Patient?  There are two techniques for draining an abscess, which have similar failure rates, but leaving a small piece of rubber through the wound rather than filling it with cloth ribbon makes it more comfortable over the next 36 hours.

Keener Kontest: Last weeks’ winner was Dr. Matt Runnalls. He is an EM physician from Cambridge, Ontario. Matt knew 3.2% of women over the age of 65, (1.9% of all people over the age of 65) present to the ED with dizziness/vertigo according to the 2017 NHAMCS database.

Listen to the SGEM podcast to hear this weeks’ question. Send your answer to TheSGEM@gmail.com with “keener” in the subject line. The first correct answer will receive a cool skeptical prize.

SGEMHOP: Now it is your turn SGEMers. What do you think of this episode on the loop technique to treat abscesses the ED? Tweet your comments using #SGEMHOP.  What questions do you have for Jay and his team? Ask them on the SGEM blog. The best social media feedback will be published in AEM.

Also, don’t forget those of you who are subscribers to Academic Emergency Medicine can head over to the AEM home page to get CME credit for this podcast and article. We will put the process on the SGEM blog:

  • Go to the Wiley Health Learning website
  • Register and create a log in
  • Search for Academic Emergency Medicine – “December”
  • Complete the five questions and submit your answers
  • Please email Corey (coreyheitzmd@gmail.com) with any questions or difficulties.

Remember to be skeptical of anything you learn, even if you heard it on the Skeptics’ Guide to Emergency Medicine.