History and development:
In 1959, a variety of cyanoacrylate adhesives were developed, some types of which are now used for surgical purposes in Canada and Europe. These glues polymerize on contact with basic substances such as water or blood to form a strong bond. The first glue developed was methyl cyanoacrylate, which was studied extensively for its potential medical applications and was rejected due to its potential tissue toxicity such as inflammation or local foreign body reactions. Methyl alcohol has a short molecular chain which contributes to these complications.
Further research revealed that by changing the type of alcohol in the compound to one with a longer molecular chain, the tissue toxicity was much reduced. All the medical grade tissue adhesives currently available for human use contain butyl-esters, which are costlier to produce.
In 1964, the Tennessee Eastman lab submitted its first application for new drug approval to the FDA. The military learned of this new glue and became extremely interested in its potential for use in field hospitals. MASH units in Vietnam were overloaded. Many solders were dying from chest and abdominal wounds, despite the best efforts of medics. In 1966 a special surgical team was flown to Vietnam, trained and equipped to use cyanoacrylate adhesive. A quick spray over the wounds stopped bleeding and bought time until conventional surgery could be performed. The possibilities were immediately seized by the medical communities of Europe and the Far East. Meanwhile the FDA changed standards and kept requesting additional data until Eastman was reluctantly forced to withdraw his application. (Jueneman, 1981)
Histoacryl Blue (n-butyl cyanoacrylate) has been used extensively in Europe since the 1970s for a variety of surgical applications including middle ear surgery, bone and cartilage grafts, repair of cerebrospinal fluid leaks, and skin closure. It has been available in Canada through Davis & Geck Canada, with no adverse effects reported to date. Further, laboratory studies have been done which concluded that it has no carcinogenic potential. Tissue toxicity has only been noted when the adhesive is introduced deep in highly vascular areas (the perineum qualifies). While I always take claims of harmlessness with a grain of salt, if used as directed, these adhesives appear to be basically safe.
(Quinn & Kissick, 1994) Current use: Although not labeled as such, over-the-counter Super Glue products contain methyl alcohol, because it is inexpensive to produce. Cyanoacrylates cure by a chemical reaction called polymerization, which produces heat. Methyl alcohol has a pronounced heating action when it contacts tissue and may even produce burns if the glue contacts a large enough area of tissue. Rapid curing may also lead to tissue necrosis. Midwives have not noted such reactions because minimal amounts are being used for perineal repair. Nevertheless, with a greater toxic potential, over-the-counter products are inappropriate for use in wound closure. (Quinn & Kissick, 1994)
Medical grade products currently available contain either butyl, isobutyl or octyl esters. They are bacteriostatic and painless to apply when used as directed, produce minimal thermal reaction when applied to dry skin and break down harmlessly in tissue. They are essentially inert once dry. Butyl products are rigid when dry, but provide a strong bond. Available octyl products are more flexible when dry, but produce a weaker bond.
When used for repair, ideally the wound to be closed is fresh, clean, fairly shallow, with straight edges that lie together on their own. The glue is applied to bridge over the closed edges; it should not be used within the wound (on raw surfaces), where it will impair epithelization. The only currently FDA approved adhesives suitable for use as suture alternatives are veterinary products; n-butyl- cyanoacrylate tissue adhesives Vetbond (3M) and Nexaband liquid and octyl-based Nexaband S/C (intended for topical skin closure when deep sutures have been placed). Histoacryl Blue (butyl based) (Davis & Geck) and Tissu-Glu (isobutyl based) (Medi-West Pharmaceuticals) are sold in Canada for human use. DMSO (dimethyl sulfoxide) or acetone serve as removers. (Helmstetter, 1995; Quinn & Kissick, 1994)
