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Three Part Question

In [adult patients presenting to the emergency department with a cutaneous abscess] does [primary or secondary closure] improve [wound healing 3 to 7 days post-attendance]?

Clinical Scenario

You treat a cutaneous abscess in young adult male in the emergency department with incision and drainage. You wonder which method of wound closure will allow the wound to heal the quickest - primary suture straightaway or leaving it to heal by secondary intention

Search Strategy

Medline (1946 to May 2014) and Embase (1980 to 2014 week 23) were both searched using the OVID interface with the following string: [exp Abscess/ OR abscess.mp OR absces$.mp OR exp Furunculosis/ OR exp Carbuncle/OR exp Soft Tissue Infections/] AND [primary closure.mp OR secondary closure.mp OR exp sutures/ OR wound closure.mp]

This gave a yield of 1676 papers and thus the searches were limited with the terms “English Language’, “Human” and “Therapy (maximises sensitivity)”

A further search of the Cochrane Library of Systematic Reviews was also performed with the use of keywords as the [exp] search term is not valid for this particular database. This yielded 36 papers.

Search Outcome

This gave a total of 533 papers. A total of 10 papers were relevant to the question and had full evaluation. From these 6 RCT’s were located, 5 of which were included in a large systematic review. References from all papers were crossed checked to ensure no papers were missed. The remaining 3 papers were not useful to the question.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Singer et al. 2013 Washington DC, USA	56 adult patients presenting to 2 academic ED’s with localised cutaneous abscess requiring I&D in the ED	Randomized Controlled Trial	1. Percentage of wounds that healed at 7 day follow up	"Primary closure - 69.6% Secondary closure - 59.3% "	"Small sample size with 8% lost of follow up. Results not statistically significant. Underpowered to detect any differences in healing rates. Element of selection bias as all patients with systemic signs of infection and significant cellulitis were excluded
			2. Treatment failure rates (at 2 days, 7 days & overall)	"Primary closure - 30.4% overall failure Secondary closure - 28.6% overall failure"
			3. Need for hospital admission & patient satisfaction	"Primary closure - 9/10 satisfaction. No hospital admissions Secondary closure - 10/10 satisfaction. 1 admission. "
Singer et al. 2011 New York, USA	915 adult patients with cutaneous abscesses in various locations randomised to primary or secondary closure	Systematic Review	1. Time to wound healing	Primary closure - 7.8 days. Secondary closure - 15.0 days	"Large number of abscesses included in trial were perianal - discussed in comments section. The majority of studies are reasonably old and therefore the scope of wound infections (e.g. MRSA prevalence) may have changed. The majority of abscesses included were closed under general anaesthetic, therefore results may be not transferrable to the emergency department.
			2. Time to return to work	"Primary closure - 4.1 days Secondary closure - 14.6 days
			3. Abscess recurrence (%)	"Primary closure - 7.6% Secondary closure - 11.1%"

Comment(s)

Despite the fact that a large number of abscesses included in the systematic review were perianal this does not affect the results as the study containing the largest number of perianal abscesses (65%) carried a minimal weight (0.06%). It does therefore appear that abscesses heal faster if they undergo primary closure. However, as mentioned above many of the abscesses drained in the systematic review were done so under general anaesthetic. It would be very hard to achieve the same level of abscess drainage in the emergency department under local anaesthetic. This is perhaps why the recent RCT above showed no difference in outcomes. Additionally there are novel ways of abscess drainage, such as loop drainage, currently being pioneered (Singer & Talan, 2014). Further trials based in the emergency room are required to determine the optimum management.

Clinical Bottom Line

There is no hard evidence suggesting that primary closed abscesses heal any faster than ones left to heal by secondary intention in the emergency department setting. The choice ultimately lies with the treating physician.

Level of Evidence

Level 1 - Recent well-done systematic review was considered or a study of high quality is available.

References

1. Singer, Adam J., et al. Primary Versus Secondary Closure of Cutaneous Abscesses in the Emergency Department: A Randomized Controlled Trial Academic Emergency Medicine 2013; 20.1: 27-32
2. Singer, Adam J., et al. Primary closure of cutaneous abscesses: a systematic review The American Journal of Emergency Medicine 2011; 29.4: 361-366