Surgical sutures, commonly known as stitches, are medical devices used to hold body tissues together after injury or surgery. They support the healing process by maintaining tissue approximation and providing structural integrity. Sutures help close wounds and incisions to promote healing, minimize scarring, and prevent infection. This temporary support allows the body’s natural repair mechanisms to form new tissue.
Types of Sutures
Absorbable sutures dissolve within the body over time, eliminating the need for manual removal. The body breaks down these materials through natural enzymatic or hydrolytic processes, typically over weeks to months. They are useful for internal tissues that heal quickly, such as those in gastrointestinal or urological surgeries, where subsequent removal would be difficult or invasive. These sutures provide temporary wound support until the tissue regains sufficient strength.
Non-absorbable sutures resist degradation and remain in the body indefinitely unless manually removed. They are chosen for situations requiring long-term tissue support and strength, such as closing skin incisions, repairing tendons, or in cardiovascular surgeries where mechanical stress is constant. For external closures, these sutures must be removed once the wound has healed adequately. Their durability makes them suitable for areas under high tension or those that heal slowly.
Suture Materials
Natural sutures, derived from biological sources, include catgut and silk. Catgut, made from purified collagen of sheep or cow intestines, is an absorbable material broken down by enzymatic action. Silk, a non-absorbable material from silkworm cocoons, is known for its high tensile strength and ease of handling, though it can elicit some tissue reaction.
Synthetic sutures offer predictable properties and often result in reduced tissue reactions. Common synthetic absorbable materials include polyglycolic acid (PGA), polydioxanone (PDS), and poliglecaprone (PGCL). Poliglecaprone, a monofilament, is known for its excellent handling, smooth tissue passage, and predictable absorption. Examples of synthetic non-absorbable sutures include nylon and polypropylene. Nylon, a polyamide, provides high tensile strength and elasticity, while polypropylene offers significant strength and is often used in areas with movement or tension due to its non-reactive nature.
Key Suture Characteristics
Suture Size
Suture size, or gauge, is standardized by systems like the United States Pharmacopeia (USP). This system uses a numbering convention where higher numbers indicate a thicker, stronger suture. Numbers with zeros (e.g., 6-0, pronounced “six-oh”) indicate finer sutures, with more zeros meaning a smaller diameter. For instance, a 2-0 suture is significantly thicker than a 5-0 suture. The smallest possible suture size that can adequately support healing tissue is generally chosen to minimize trauma and foreign material in the wound.
Needle Types
Surgical needles, attached to the suture thread, come in various shapes and point types designed for specific tissues. Curved needles are commonly used in general surgery, while straight needles suit superficial skin suturing. Needle points are either cutting or non-cutting (tapered).
Cutting needles have a triangular tip with sharp edges, ideal for penetrating tough tissues like skin. Reverse cutting needles have the cutting edge on the outer curve, which may reduce the likelihood of the suture pulling through soft tissue. Tapered needles, with a round, smooth shaft, are used for delicate, easily torn internal tissues such as bowel or blood vessels.
Applications and Post-Procedure Care
Sutures are used for closing skin incisions, repairing internal organs, in vascular procedures, and for orthopedic repairs. They provide mechanical support, holding the edges of a wound together during the initial healing phase. This approximation allows new cells and tissues to grow and bridge the gap, restoring the integrity of the injured area.
Non-absorbable sutures placed externally require removal once the wound has healed sufficiently. The typical timeframe for removal varies based on wound location, reflecting differences in healing rates and tension. For example, facial sutures may be removed within 4 to 7 days due to rapid healing, while sutures on the trunk or extremities might remain for 7 to 14 days, and those over joints up to 14 to 21 days. Prompt removal helps prevent suture marks and reduces infection risk.
Post-procedure care is important for optimal healing and to prevent complications. Patients are advised to keep the sutured wound clean and dry, especially for the first 24 to 48 hours. After this initial period, gentle cleaning with mild soap and water may be permitted, followed by careful drying. Activities that might strain the wound area should be avoided. Swelling, redness, pus, or increasing pain could indicate a potential issue, and medical attention should be sought if these signs appear.