Closing the gap for wound closure

2 mins read

Topical skin adhesives are liquid cyanoacrylate monomers that polymerise into long solid chains upon contact with an activator, moisture, or blood, to hold a wound closed.

(Image credit: HB Fuller)

In more simple terms, Jackie Klotz writes in The Glue Blog that these are medical grade glues that, when activated, can dry into a plastic or resin that can close a wound. This is an important breakthrough for treating lacerations or cuts, as topical skin adhesives can be used to replace traditional suturing methods. Sutures can be just as painful as the laceration itself, so topical skin adhesives are one way to keep additional pain at bay.

There is a long history of using cyanoacrylate chemistries in medical applications. Cyanoacrylate glue is widely used in human and veterinary medicine. It was in veterinary use for mending bone, hide, and tortoise shell by the early 1970s or before. A cyanoacrylate spray was used in the Vietnam War to reduce bleeding in wounded soldiers until they could be taken to a hospital. n-Butyl cyanoacrylate has been used medically since the 1970s. In the US, due to its potential to irritate the skin, the US Food and Drug Administration (FDA) did not approve its use as a medical adhesive until 1998 with Dermabond (2-octyl cyanoacrylate). A 1986 independent study suggests that cyanoacrylate can be safer and more functional for wound closure than traditional suturing (stitches).

Two of the most common types of topical skin adhesives in the cyanoacrylate space are based on octyl and butyl chemistry formulations. Most butyl chemistry formulations activate (start to polymerise) when they come in contact with tissue, fluid or blood. Conversely, octyl chemistry formulations activate (start to polymerise) when two active ingredients come in contact with each other. But the differences don’t stop here.

Understanding the difference between the two chemistry types can be important when it comes to deciding which type of topical skin adhesive to use.

The chart on the following link is a good way of understanding the attributes that differentiate these chemistries.

When closing a wound, it is important to consider the strength and flexibility of the bond, and the set time (also known as the time it takes for a glue to cure).

Let’s consider for a moment why each of these attributes might be important. Strength is essential because the adhesive must be able to hold the edges of the wound together to avoid the reopening of wounds. Flexibility, which is closely related to strength, allows for the adhesive to adapt as the skin is stressed or flexed. Finally, set time is essential because we need to be able to treat the wound quickly without waiting for the glue to set or sutures to be put in place.

Using the chart, it is clear that while Octyl chemistry formulations might have a weaker bond and take more time to cure, they are more flexible and can adapt to the changes and stresses that skin or lacerations might experience post treatment. Conversely, while Butyl chemistry formulations are less flexible, they have stronger bonds and take less time to cure.

In an ideal setting, there would be a cyanoacrylate that has a strong bond, is flexible and takes less time to dry. This would result in better outcomes for the patient and the person applying the topical skin adhesive. That is why Histoacryl Flexible was developed.

Histoacryl Flexible

The topical tissue adhesive and microbiological barrier product, Histoacryl Flexible, consists of n-butyl-2-cyanoacrylate and a softener, which polymerises quickly in connection with tissue fluid.

For easy assessment of the thickness of the layer that has been applied, Histoacryl Flexible is coloured blue. An applicator tip facilitates creation of longer layers onto the surgical incision. Advantages of using Histoacryl Flexible include: easy application, ready-to-use, faster closure times compared to sutures, time and cost savings, less pain than a suture repair and has an effective microbial barrier.

The properties and advantages of Histoacryl remain undisputed: there are no needle holes, the wound can be closed more quickly, and there is no subsequent removal of sutures. The tissue adhesive also has a high mechanical strength and achieves excellent cosmetic results.