Sutures are medical threads used to close wounds or surgical incisions. They play a fundamental role in assisting the body’s natural healing process by holding tissues together. Absorbable sutures represent a specialized category of these medical threads, designed with materials that the body can naturally break down and absorb over time. This distinct characteristic eliminates the need for a separate procedure to remove the stitches, offering convenience and reducing patient discomfort.
How Absorbable Sutures Dissolve
The primary mechanisms for absorbable sutures to disappear involve either enzymatic degradation or hydrolysis, depending on the material composition. Natural absorbable sutures, such as catgut, primarily break down through enzymatic degradation. Enzymes present in the body’s tissue fluids attack and dismantle the suture material into smaller molecules, which the body then absorbs and metabolizes.
Synthetic absorbable sutures, conversely, degrade mainly through a process called hydrolysis. In hydrolysis, water molecules within the tissue penetrate the suture material, progressively breaking down its chemical bonds. This process gradually diminishes the suture’s tensile strength until it is fully absorbed. The rate at which these sutures degrade and are absorbed varies based on factors like the material, the implantation site, and an individual’s metabolic rate, with absorption times generally ranging from a few days to several months.
Types and Materials of Absorbable Sutures
Absorbable sutures are crafted from both natural and synthetic materials. Natural absorbable sutures are typically derived from animal collagen. Plain catgut, for instance, is made from purified collagen sourced from the intestines of sheep or cattle. Its tensile strength usually retained for about 7 to 10 days, and it is absorbed by enzymatic degradation. Chromic catgut, a modification of plain catgut, is treated with chromic salts to slow down its absorption rate, extending its tensile strength retention to approximately 10 to 21 days.
Synthetic absorbable sutures, offering more predictable performance, are widely used. Polyglactin 910, commonly known as Vicryl, is a braided multifilament suture composed of glycolide and lactide copolymers. It retains significant tensile strength for about 14 to 21 days and is typically absorbed by the body within 60 to 90 days. Polydioxanone, or PDS, is a monofilament synthetic suture known for its prolonged strength retention, maintaining approximately 70% of its initial strength for two weeks and fully absorbing within 180 to 210 days. Poliglecaprone 25, often referred to as Monocryl, is another monofilament synthetic material that rapidly loses tensile strength, with about 50% loss within 7 to 14 days, and is completely absorbed in approximately 90 to 120 days.
Medical Uses of Absorbable Sutures
Absorbable sutures are frequently chosen for medical procedures where temporary tissue support is needed and subsequent suture removal is impractical or undesirable. These sutures are widely used for closing internal tissues and organs, such as in gastrointestinal or gynecological surgeries, where access for removal would require another intervention.
They are also commonly employed in pediatric surgery, avoiding the need for children to undergo a second procedure for suture removal. Absorbable sutures are suitable for subcutaneous closures, which involve stitching layers beneath the skin, and for ligating blood vessels, preventing blood flow in specific areas. In external skin closures, especially where cosmetic results are important or patient comfort is prioritized, absorbable sutures can be used to minimize scarring and eliminate the need for manual removal. The selection of a specific absorbable suture depends on the tissue type, the wound’s characteristics, and the required healing time.
Absorbable Versus Non-Absorbable Sutures
The choice between absorbable and non-absorbable sutures depends on the specific surgical context and the duration of wound support required. Their primary benefit is eliminating the need for a follow-up procedure to remove the stitches.
Non-absorbable sutures, in contrast, are made from materials that the body cannot break down, meaning they remain intact unless manually removed. These sutures are often used when long-term tissue support is necessary, such as in certain cardiovascular surgeries or for external skin closures that will be removed once healing is sufficient. While absorbable sutures dissolve over weeks to months, non-absorbable sutures can remain in place indefinitely or until a healthcare professional removes them. The material composition also differs, with absorbable sutures often being biodegradable synthetic polymers or natural materials, while non-absorbable ones can include silk, nylon, or polypropylene.