A suture, commonly known as a stitch, is a medical device used to hold body tissues together after an injury or surgery. Its primary function is to approximate the edges of a wound, allowing the body’s natural healing processes to bridge the gap. By keeping the tissue edges aligned and under controlled tension, sutures promote efficient repair and minimize the risk of infection and scarring.
Types of Suture Materials
The choice of suture material depends on whether the wound requires temporary support or long-term strength, dividing them into two main categories based on how the body interacts with them. The material’s composition dictates its fate within the body and determines if stitch removal will be necessary.
Absorbable Sutures
Absorbable sutures are designed to lose their strength and disappear naturally within the body over time, eliminating the need for manual removal. Historically, natural materials like Catgut were used, but modern medicine favors synthetic absorbable sutures for their predictable degradation. Common synthetic examples include polydioxanone (PDS) and polyglactin 910 (Vicryl). These threads are primarily used for internal closures, such as stitching deep layers of tissue or internal organs, where removal is difficult. The absorption time ranges from a few weeks to many months, ensuring the wound is supported until it regains sufficient strength.
Non-Absorbable Sutures
Non-absorbable sutures are made from materials the body cannot break down, meaning they retain their strength indefinitely. These materials are used externally on the skin, requiring manual removal once the wound has closed, or internally in situations demanding permanent support. Natural non-absorbable options include silk. Synthetic non-absorbable sutures are commonly made of polymers like nylon, polypropylene, or polyester. When used internally, such as in orthopedic or cardiovascular procedures, these materials become permanently encapsulated by the body’s tissues.
Different Stitching Techniques
The way a thread is placed and tied is known as the stitching technique. This mechanical pattern significantly impacts wound security, tension distribution, and the resulting scar appearance. Surgeons choose a technique based on the wound location, the tension across the wound, and the desired cosmetic outcome.
Simple Interrupted Suture
The simple interrupted suture is the most fundamental and widely used technique, involving individual stitches that are placed, tied, and cut separately. This method offers high security because if one stitch fails, the others remain intact to hold the wound closed. Interrupted sutures allow the surgeon to precisely adjust the alignment of the wound edges, which is beneficial for complex or irregularly shaped lacerations.
Continuous Suture
A continuous suture, also known as a running suture, involves a single, unbroken thread that progresses along the length of the wound. This technique is faster to apply than the interrupted method, making it suitable for closing long incisions. It distributes tension evenly across the entire wound. However, if the continuous line breaks at any point, the integrity of the entire closure can be compromised.
Subcuticular Suture
For wounds where cosmetic appearance is a high priority, the subcuticular suture technique is often employed. In this method, the thread is placed horizontally just beneath the outer layer of the skin, within the dermis, without penetrating the surface. Because the stitch remains buried, this technique avoids the small puncture marks and scarring associated with external sutures. Subcuticular closures are typically used in areas of low tension and often utilize absorbable material for an aesthetically pleasing result.
Alternatives to Traditional Sutures
While traditional sutures remain versatile, several modern methods are used as alternatives depending on the wound type and location. These alternatives offer benefits like speed of application, reduced discomfort, or superior cosmetic outcomes.
Surgical Staples
Surgical staples are a fast and reliable alternative, useful for closing long incisions or wounds in areas under high tension or movement, such as the scalp or abdominal wall. The sterile metal staples are applied with a specialized device and offer strength. They must be manually removed by a healthcare professional once the wound is sufficiently healed.
Tissue Adhesives (Surgical Glue)
Tissue adhesives, often called surgical glue, are medical-grade liquid polymers used for closing small, superficial wounds with minimal tension. The glue is applied externally and hardens quickly to hold the wound edges together. A major advantage is that the adhesive naturally flakes off as the skin heals, eliminating the need for a follow-up removal appointment.
Adhesive Strips
Adhesive strips, such as Steri-Strips, are non-invasive options used for small, straight cuts or to provide additional support after staples or sutures have been removed. These reinforced tapes pull the superficial edges of the skin together. They are often preferred for fragile skin where a needle might cause damage and can be easily removed at home.