Feeling Argumentative

In this series we are going to pick apart the arguments and evidence surrounding a common but controversial topic in Emergency Medicine. The goal is to take a hard look at the practices we are handing down to future generations of ED docs and see what is based on opinion and what is based on evidence.

An Abscess Worth Packing

Do we really need to pack abscesses after incision and drainage?

Cutaneous abscesses are a common occurrence in the Emergency Department (ED), and yet most emergency physicians manage this condition based on anecdote and knowledge given to them by the physicians who trained them. And those physicians got it from the physicians who trained them, and they got it from the physicians who trained them, and… you get it. One would think based on this lineage of knowledge that the subject simply has never been placed under scientific scrutiny. However, there actually have been studies performed on this topic, and their results throw a lot of the common practices and beliefs into question.

Arguments against packing:

Literature Review:

The paper by O’Malley et al is the only paper to date that compares incision and drainage (I&D) of simple cutaneous abscesses with packing to I&D without packing in adult ED patients. Abscesses needed to be <5 cm on the trunk or extremities and were not perianal, pilonidal, peri-genital, facial or on the hands/feet. Patients with hidradenitis suppurativa were also excluded. It was a prospective, single center, single-blinded, randomized control trial with a total of 48 completing the study. There were 23 randomized to packing group, 25 to the nonpacking group. All patients were given prescriptions for TMP/SMX 800 mg/160 mg q12h, oxycodone/acetaminophen 5/325 q4h prn and ibuprofen 600 mg q4h prn.

Patients rated pre-procedure pain, during-procedure pain and post-procedure pain on a 100 point visual analog scale. The patients were then told to return to ED at 48 hours for follow up where a research assistant removed the dressing and 2 consecutive blinded physicians evaluated the wound. Primary outcome was the need for intervention at 48 hour follow up, of which there was no statistical difference between the groups. The analysis of the patient’s pain scores showed that the non-packed group had significantly lower pain scores both immediately post-procedure and at 48 hour follow up.

Interestingly, 11/25 (46%) of the non-packed group did not return for repeat evaluation at 48 hours whereas only 3/23 of the packed group did not return for reevaluation. Normally this poor adherence to the protocol would be an indicator of a poor study, however, 10/11 non-packed participants were contacted by telephone (except the 1 lost to follow up) and stated they were not having pain, did not think their abscess needed to be reevaluated, and did not want to return to the ED. Therefore, in this case it could be argued that, although this is indeed not ideal in terms of scientific methodology, this is likely a sign of success of the non-packing strategy. 75% of participants from both groups were contacted 10-15 days after the initial visit and none had required any additional intervention and none reported any complication.

Although this study was small, it certainly suggests that not packing abscesses is equally as safe when compared to packing. Also, based on the results it would likely decrease the number of return ED visits since almost half of the non-packing group decided follow up was unnecessary given the symptoms and appearance of their abscess whereas 87% of the packing group followed up and were having significantly more discomfort.

The studies by Leinwand et al and Kessler et al were randomized controlled trials of non-packing vs. packing post I&D in pediatric patients (ages 1-25 in Kessler’s study and 1-18 in Leinwand’s study). Both studies were slightly larger than O’Malley’s, Kessler’s with n= 57 and Leinwand’s with n=85. The designs of both studies were similar to that of O’Malley’s with some slight differences. Both trials included larger abscesses than O’Malley and Leinwand gave antibiotics while Kessler did not. Both of these trials showed that there was no increase in abscess recurrence or need for a second intervention between the two groups. Of note, Kessler’s study did not find that there were decreased pain scores in the non-packing group when compared to the packing group. Leinwand’s study did not evaluate pain scores.

In a study by Singer et al, primary closure of cutaneous abscess in the ED was compared to secondary closure. 56 patients were randomized to either I&D with packing or closure with sutures. Abscesses were mainly located on trunk or extremities and they ranged in size from 1 to 150 cm. Antibiotic administration was left up to the treating physician and an equivalent number of patients in each group received antibiotics. In other words, they performed a randomized controlled trial comparing suturing the I&D site closed vs leaving it open and packing it. They found no difference in rates of healing or of treatment failure at 7 days. Yes, you read that right, you can suture close an abscess after you incise it and, amazingly, the patients did just fine.

Arguments for packing:

Literature Review:

To the best of my knowledge, and to the best of the knowledge of O’Malley et al, there is no literature to date that describes the benefit nor the necessity of packing post-I&D. In fact, despite my best efforts, I haven’t been able to figure out where this idea even came from. The theoretic utility of gauze packing is to fill the abscess cavity to prevent bacteria from reaccumulating and also to prevent the occurrence of a seroma. And yet, I can’t find any evidence – not even animal studies – that either of these phenomena occur. If you find something please put it in the comments or email me.

What I could find were surgical papers (Dinah and Adhikari, Dawson et al) discussing what packing material to use for post-surgical wounds left to heal by secondary intent including cutaneous abscess. These studies were primarily focused on treating large abscesses that required many dressing changes over days to weeks. They found that while saline soaked gauze was the most common packing material, there are more modern products such as calcium alginate that improve patient tolerance of dressing changes. Modern materials also decreased the number of dressing changes required to achieve clinical cure. It is important to note that the cost of these materials may be prohibitive for smaller abscesses. So, if you feel that an abscess absolutely must be packed, consider using something like alginate instead of gauze.

Logical Fallacies:

  • Misleading vividness: “well I had a patient once who I forgot to put packing in and the abscess literally never healed, they didn’t follow up, their arm fell off, then they died. So now I always pack my abscesses.”
    • If this actually happened, it’s an outlier. Outliers do happen but it’s so rare that you don’t need to worry about it. This is what evidence based medicine is all about, producing generalizable recommendations so we don’t rely on anecdotal experiences.
  • Appeal to common practice: “well you’ll find that most people use packing after their I&Ds, are you trying to say they’re all wrong?”
    • This is the classic “if all your friends jumped off a bridge would you do it too” question. Again, as the evidence above points out, it probably isn’t “wrong” to pack an abscess but it probably isn’t “right” either.

Take Home Points:

  • There is one small single blinded ED-based RCT of packing vs. non-packing of truncal/extremity cutaneous abscesses <5 cm in adults. The non-packed group had lower pain scores and had no difference in clinical outcome.
  • There are several small RCTs of packing vs non-packing in pediatric patients. The non-packed groups had no difference in clinical outcome or pain scores.
  • There are no studies supporting the use of packing for cutaneous abscesses. The idea is rooted only in tradition and on a theory which, to my knowledge, has never been demonstrated to have a scientific basis.

It is difficult to make practice changing recommendations from small, not particularly robust, trials. The fact still stands that there are several prospective randomized controlled trials evaluating the use of packing vs non-packing. And the evidence, albeit weak, shows that not packing wounds is equally safe when compared to shoving a bunch of gauze inside someone’s inflamed, freshly cut open skin. Of note, the IDSA guidelines for management of skin and soft tissue infections post-I&D do not recommend for or against packing but hedge toward not packing by citing the O’Malley study.

P.S.

…If all this has you in a tizzy and you don’t want to worry about this packing vs no packing debate at all, I’ll loop you in on some alternative I&D techniques in the next post in this series.

Alexander “Zander” Prewitt is an EM Resident, Class of 2020