Morgenstern, J. Laceration repair: Does eversion matter?, First10EM, November 21, 2022. Available at:
If you have attended medical school, one ‘fact’ I guartunee you have heard is that wound eversion is the key to good cosmetic repair of lacerations. Many studies I have read just assume that eversion is important, and search for the repair technique that results in the best eversion. In other words, eversion is used as a surrogate outcome for better wound repair. But is it a good surrogate? Honestly, it never made much sense to me. Why would you want to tissue lying in a non-anatomic position? (The theory is that the edges will retract, and any indentation will catch the light and cause a more visible scar. But is that theory more believable than the theory that a good anatomic repair will result in the best outcomes?)
This dogma seems to arise from the era before evidence based medicine, so even following citation chains back as far as they go doesn’t lead to any evidence for this practice. (If you know where this dogma originated, or have evidence that eversion is important, please send it my way.) As far as I know, Kappel 2015 is the only trial to ever address this question. In their introduction section they state that, “data supporting improved outcomes with eversion are limited. No studies, to our knowledge, have directly addressed this facet of wound closure.”
Kappel 2015 in a single center randomized trial looking at 50 adult patients undergoing dermatologic procedures. Wounds were divided in half. Half of the wound was closed using a suture designed to produce eversion (“dermal set-back or inverted vertical mattress suture, depending on surgeon preference”), and the other half of the wound was closed the simple interrupted sutures with the aim of ‘planar’ closure. At 3 and 6 month follow-up, there was no difference in the appearance of the wound based on the “Patient Observer Self-Assessment Scale”, nor were there objective differences in measured height, width, or depth of the scars. This is a single center study, with incomplete follow-up, incomplete blinding, inadequate allocation concealment, and incomplete follow-up. It is not a high level of evidence, but it is literally all the evidence we have. I think the outcome fits with simple common-sense physiologic reasoning: there is no benefit of eversion over simple planar wound closure.
There is also a fair amount of indirect evidence that eversion doesn’t matter, which will be covered in the other topics in this series. Outcomes are identical with essentially every repair technique described. Dermabond and steristrips result in identical outcomes to sutures. Considering that glue and steristrips do not achieve any degree of eversion but result in identical outcomes, these studies provide relatively strong indirect evidence that eversion is unimportant.
There is very little evidence to guide us, but the necessity of eversion in wound repair seems to fall into the medical dogma camp. Personally, I try to get tissues as close as possible to their original anatomic position, which would be described as a ‘planar repair’ in this dermatology literature.
Kappel S, Kleinerman R, King TH, Sivamani R, Taylor S, Nguyen U, Eisen DB. Does wound eversion improve cosmetic outcome?: Results of a randomized, split-scar, comparative trial. J Am Acad Dermatol. 2015 Apr;72(4):668-73. doi: 10.1016/j.jaad.2014.11.032. Epub 2015 Jan 23. PMID: 25619206