Medical adhesive is used for implants, in surgery and for wound closure in open wounds. In addition to fibrin, which is an endogenous and hemostatic adhesive, cyanoacrylate ester preparations are mainly used as medical adhesives today. The invention of these adhesives has already saved millions of lives.
What is medical adhesive?
In addition to tear resistance, medical adhesives must be compatible with tissues. To close tissue defects, unite different tissues and fix implants such as prostheses, human medicine has used adhesive in some cases since the 20th century. In addition to tear resistance, medical adhesives must above all exhibit tissue compatibility. This tissue compatibility is ensured for the individual preparations in the course of stringent tests. In the 1950s, the surgical industry experimented for the first time with cyanoacylate preparations as medical adhesives. The principle of these adhesives was to polymerize in contact with body fluids such as blood. This polymerization forms a water-resistant bridge that seals wounds with a stable bond. Methyl cyanoacrylate in particular, which was used at the time, was soon discarded because of the toxicity of the monomers it contained. Because of the shortness of the carbon bridge, inflammatory reactions and foreign body reactions were side effects. The variations of the first polymerizing adhesives still in use today form longer bridges without tissue toxicity.
Forms, types, and styles
Today, the main types of medical adhesives used are long-chain cyanoacrylate ester preparations and fibrin glues. Fibrin glues are used specifically for internal use. This means that they play an important role in internal organs and in all types of surgery. A distinction must be made between these and superficial skin adhesives, which have to satisfy less stringent requirements and contain N-butyl cyanoacrylate in particular as the active ingredient. This medical adhesive has been used in Europe since about the 1970s, when it was even used in the middle ear and for bone grafts. Today, the adhesive is used almost exclusively to seal skin wounds and to fix bones. In today’s use, the substance is not expected to cause any side effects or carcinogenic effects. However, the use of this adhesive compound in deeper tissues or enormously vascularized tissues can under certain circumstances be associated with tissue toxicity, so that fibrin is used more frequently in this context because of its biological origin. Bone adhesives in use include methyl polymethacrylates because they can withstand higher stresses.
Structure and mode of operation
Octyl cyanoacrylate ester preparations contain monomers. These monomers, when in contact with various body fluids, can cause a chemical reaction known as polymerization. A polymer is a chemical substance made of macromolecules. This substance forms during the reaction of octyl cyanoacrylate ester preparations and body fluids, forming a bridge to which monomers are continuously attached. This reaction is an anion-induced and exothermic polymerization in which water and alcohols play an important role. Today, medical liquid adhesives for wound closure contain various ester types, such as butyl, octyl or isobutyl esters. They all have a bacteriostatic effect, but differ in their strength. Fibrin differs from cyanoacrylate ester preparations in that it is a biological substance. This physiological two-component adhesive plays a role in the body’s processes of wound closure. Human blood contains the protein fibrin. The precursor of this fibrin is fibrogen, which reacts with platelets to close wounds and forms a crust. In the 1970s, medical science first isolated these components from blood to use as an adhesive during surgery. Because of its proximity to the human body, this adhesive is completely degraded by the organism after a considerable time. Methyl polymethacrylates, which can make materials such as plastic and metal adhere and are temperature-resistant and elastic, are often used as bone adhesives for implants. Only through elasticity can they transfer forces to the bone and withstand the high stress caused by body weight.
Medical and health benefits
The history of medical adhesive and the health benefits of this invention begins roughly with the Vietnam War in the 1960s. At that time, despite relatively good, medical care, masses of soldiers in the war zone succumbed to their chest and abdominal wounds because they had to wait too long for surgical treatment. By the mid-1960s, medical glue was already being used in the Vietnam War. The use of these preparations caused deaths to decline. Wounds could be closed with immediate effect within minutes, at least superficially. Infections were reduced in this way. Many people could thus be saved from bleeding to death or death from sepsis. Even today, medical glue saves lives. During operations, for example, fibrin, which stops bleeding, can prevent serious complications with little time expenditure. Medical skin adhesives also have a time-saving effect. They can be used to close open wounds in a very short time and are clearly superior to sutures in terms of the time required. Since time can make the difference between life and death, especially in medicine, the medical benefits of adhesives are high. A combination of sutures and medical adhesive is also often used to close wounds. For example, the adhesive can be used to support heavy or complex sutures. Healing is thus often less complicated, and doctors can prevent sutures from coming loose involuntarily after surgery. Medical adhesive offers other advantages over sutures in addition to saving time. Compared with sutures, for example, the adhesive triggers less skin irritation and itching.
