This technique does not typically permit the same degree of wound-edge apposition as can be accomplished with other transepidermal sutures, since the everting effect of the suture technique may be associated with a small degree of gaping at the center of the horizontal mattress suture. In the event that deeper sutures were carefully placed, this may not be a significant drawback, since the wound edges may be well-aligned from the placement of these deeper sutures. If not, or if there is a need for improved wound-edge apposition even after placing the horizontal mattress suture, a small simple interrupted suture may be placed centrally over the horizontal mattress suture to bring the wound edges together more precisely.
Suture removal with this technique may be more involved than with simple interrupted sutures, particularly if sutures are left in situ for an extended period of time and some of the suture material has been overgrown by the healing epidermis, as the knot may be somewhat buried in the context of a ridged everted repair.
With any suturing technique, knowledge of the relevant anatomy is critical. When placing a horizontal mattress suture it is important to recall that the structures deep to the epidermis may be compromised by the passage of the needle and suture material. For example, the needle may pierce a vessel leading to increased bleeding.
Similarly, particularly if the knot is tied relatively tightly, structures deep to the defect may be constricted. This can lead to necrosis due to vascular compromise or even, theoretically, superficial nerve damage. These concerns are more acute with the horizontal mattress suture than with the simple interrupted suture, since the wide arc of the suture material and its horizontal component incorporate more skin and underlying structures, thus increasing the risk of strangulation.
The potential to constrict deeper structures may be used to the surgeon's advantage in the event that a small vessel deep to the incision line is oozing; rather than opening the wound, localizing the source of the bleed, and tying off the individual vessel, it may be possible to simply place a horizontal mattress suture incorporating the culprit vessel within its arc, tie it tightly, and thus indirectly ligate the vessel. This should only be used in the event that the offending vessel is relatively small, since otherwise there is a significant risk that this indirect ligation will not be sufficiently resilient. Moreover, tying the suture too tightly may increase the risk of developing track marks or superficial necrosis.
This technique may elicit an increased risk of track marks, necrosis, and other complications when compared with techniques that do not entail suture material traversing the scar line, such as buried or subcuticular approaches. Therefore, sutures should be removed as early as possible to minimize these complications, and consideration should be given to adopting other closure techniques in the event that sutures will not be able to be removed in a timely fashion.