A surgical adhesive is a specialized medical material designed to bind tissues together, seal wounds, or attach medical devices within the body. These advanced substances offer an alternative or supplement to traditional wound closure methods, such as sutures or staples. They are engineered to provide a secure bond, promoting healing and potentially reducing patient discomfort and recovery time.
Types of Surgical Adhesives
Surgical adhesives are categorized primarily by their chemical composition and origin, each possessing distinct properties. Fibrin sealants represent a biological class, derived from human or animal blood proteins, specifically fibrinogen and thrombin. When combined, these components mimic the body’s natural clotting cascade, forming a resilient fibrin clot. This type of adhesive is often supplied as two separate solutions that mix upon application.
Another significant category includes synthetic cyanoacrylates, which are medical-grade versions of fast-acting “super glues”. These adhesives are synthetic polymers that rapidly bond upon contact with moisture. Different cyanoacrylate formulations, such as 2-octyl cyanoacrylate, offer varying degrees of flexibility and degradation rates, making them suitable for specific applications.
Polyethylene glycol (PEG) polymers form a third class of synthetic surgical adhesives, often presenting as hydrogels. These water-based gels create a flexible, watertight seal when applied to tissue. PEG-based adhesives are known for their excellent biocompatibility and can be designed to degrade over time within the body.
How Surgical Adhesives Function
The mechanism by which surgical adhesives create a bond varies depending on their composition. Fibrin sealants work by replicating the final stages of the body’s physiological blood coagulation system. When fibrinogen and thrombin solutions are mixed at the wound site, thrombin cleaves fibrinogen, initiating its polymerization into fibrin monomers. These monomers then cross-link, forming a stable, three-dimensional fibrin clot that adheres to the tissue surface.
Cyanoacrylate adhesives, on the other hand, function through a chemical reaction called anionic polymerization. Upon contact with moisture or anions naturally present on tissue surfaces, the liquid cyanoacrylate monomers rapidly link together to form long polymer chains. This process creates a strong, flexible film that securely bonds the approximated tissue edges.
PEG polymers bond through a cross-linking reaction. When two components of a PEG-based system are mixed or exposed to a specific trigger, such as light, they rapidly polymerize to form a hydrogel. This gel adheres to the tissue surface, creating a barrier or seal.
Applications in Medical Procedures
Surgical adhesives are employed in a broad range of medical procedures, offering distinct advantages over traditional closure methods. For external skin closure, they are frequently used to seal simple cuts and lacerations or surgical incisions, particularly on the face or scalp, where they can result in less noticeable scarring compared to stitches. This application is common in emergency room settings or after minor surgical procedures.
Internally, these adhesives are used to seal tissues and prevent leaks from organs after trauma or surgery. For instance, they can seal air leaks from the lungs following thoracic procedures or fluid leaks from the liver or spleen after injury. This sealing capability helps to minimize complications such as fluid collections or pneumothorax.
In more specialized fields, surgical adhesives play a significant role in vascular and neurological surgery. They can reinforce suture lines on blood vessels, particularly in delicate anastomoses, providing an additional layer of sealing to prevent leaks. Adhesives are also used to seal the dura mater, the protective membrane covering the brain and spinal cord, to prevent cerebrospinal fluid leakage after neurosurgical interventions. Additionally, they can attach surgical mesh to the abdominal wall during hernia repair, offering a less invasive method of fixation.
Interaction with the Human Body
Surgical adhesives are designed to interact safely with the human body through biocompatibility. This means they are engineered not to cause significant harmful immune responses or adverse tissue reactions. Acceptance by the body is a requirement for clinical use.
Many surgical adhesives are also designed to be biodegradable, meaning they are gradually broken down and absorbed by the body over time. For example, fibrin sealants degrade into granulation tissue in about two weeks after application. This allows the body’s natural healing processes to take over as the wound gains strength, eliminating the need for a second procedure to remove the adhesive.
However, not all surgical adhesives are fully biodegradable. Some cyanoacrylate adhesives slough off with skin exfoliation, while longer-chain versions degrade more slowly. Safety considerations include localized tissue inflammation or allergic reactions, or deeper tissue damage if the adhesive penetrates below the skin during application.