Absorbable SutureEdit

Absorbable sutures are surgical thread formulations designed to be broken down and absorbed by the body over a finite period after implantation, eliminating the need for later removal in many settings. They are a key component of wound closure in internal tissues where long-term foreign material can complicate healing or require a second procedure for removal. While they share the basic purpose of approximating tissue edges, absorbable sutures differ widely in composition, absorption profile, tensile strength, and tissue compatibility, making material selection a nuanced clinical decision. For a broader understanding of sutures in general, see Suture and Surgical suture.

Like other suture materials, absorbable options can be broadly categorized into natural and synthetic types. Natural absorbables, such as catgut derived from animal collagen, were long used but have declined in favor due to variability in absorption and tissue response. Modern practice favors synthetic absorbables, which offer more predictable performance and a wider range of absorption timelines. See catgut for historical context and polydioxanone or polyglactin 910 for representative modern examples.

History and development

The use of absorbable materials for wound closure predates modern plastics, with natural collagen-based products such as gut sutures used for centuries in various surgical traditions. The 20th century brought a transition to synthetic polymers with more uniform behavior. Innovations introduced polymers that hydrolyze or otherwise degrade in biological environments, allowing surgeons to tailor how long a suture maintains strength and how quickly it is resorbed. Major suture families include polyglycolic acid polyglycolic acid (Dexon), polyglactin 910 polyglactin 910 (Vicryl), polydioxanone polydioxanone (PDS), poliglecaprone 25 poliglecaprone 25 (Monocryl), and polyglyconate polyglyconate (Maxon). These materials are discussed in more detail under the sections that follow.

Materials and types

Natural absorbable sutures

Catgut: A historically common natural suture made from collagen, typically treated to influence absorption. Absorption is mediated by proteolytic digestion in the body, and strength retention can vary between patients and wound contexts. Because of variability and potential reactivity, catgut use has diminished in many modern procedures. See catgut for more.

Synthetic absorbable sutures

Synthetic absorbables are engineered to degrade primarily through hydrolysis, producing more predictable strength retention and absorption timelines. Key members include:

poliglecaprone 25 (poliglecaprone 25), commonly known by the trade name Monocryl: fast to intermediate absorption, with rapid loss of tensile strength. Often used in mucosal and subcutaneous closures where minimal tissue reactivity is desired.
polyglactin 910 (polyglactin 910), known as Vicryl: a braided polymer with predictable absorption and substantial initial strength, suitable for many soft-tissue closures.
polydioxanone (polydioxanone), marketed as PDS: retains tensile strength for a longer period and can be used in deeper or heavier tissue closures where prolonged support is advantageous.
polyglycolic acid (polyglycolic acid), sold as Dexon: another braided option with a balance of strength and absorption time.
polyglyconate (polyglyconate), sold as Maxon: offers extended strength retention with gradual hydrolysis, often chosen for tissues requiring longer-lasting support.

Each material has a characteristic profile for initial tensile strength, rate of loss of strength, total absorption time, and tissue reactivity. The choice depends on location, tissue type, anticipated mechanical demands, infection risk, and whether a rapid or slower absorption is clinically advantageous. For broader material comparisons, see absorbable suture and the pages on each polymer listed above.

Absorption mechanisms and duration

Absorption of synthetic absorbables is predominantly driven by hydrolysis of the polymer backbone, gradually reducing molecular weight until the material is no longer recognized as a discrete foreign body. Natural materials like catgut rely on proteolytic enzymes to degrade collagen fibers, resulting in variable absorption. Absorption timelines vary widely: - Fast-absorbing sutures may lose most tensile strength within 7–14 days and completely resorb over 21–60 days. - Intermediate forms maintain significant strength for several weeks and may resorb over 60–90 days. - Longer-duration absorbables can retain meaningful strength for 4–6 weeks or more and may take several months to fully absorb. Manufacturers provide typical ranges based on standardized tests and clinical experience, but actual performance depends on patient factors (age, nutritional status, comorbidities), wound environment (contamination, tissue ischemia), and suture placement (depth, knot security). See hydrolysis for the chemical process underlying hydrolytically degradable polymers.

Clinical considerations and practice

Absorbable sutures are favored when long-term presence of suture material is undesirable or when a second procedure to remove sutures would impose unnecessary risk or cost. They are especially useful in internal tissues where permanent implants could provoke chronic inflammation, granuloma formation, or infection risk. Important considerations include: - Tissue type and location: mucosa, subcutaneous tissue, or deeper planes may benefit from different absorption profiles to balance early apposition with long-term support. - Infection risk: in contaminated or high-risk wounds, faster-absorbing materials may reduce foreign-body load, while slower-absorbing options could sustain support in healing tissue. - Tensile needs: areas under sustained mechanical stress may require materials with longer strength retention, such as polydioxanone-based sutures. - Patient factors: nutritional status, diabetes, smoking, and age can influence collagen-based absorption rates and inflammatory responses. - Handling and knot security: synthetic absorbables vary in handling characteristics, memory, and knot-tying properties, which can influence the reliability of wound closure in different surgeons’ hands.

In practice, surgeons often select absorbable sutures to minimize follow-up visits, especially in outpatient or pediatric settings, while balancing the need for adequate wound support during the critical healing window. See suture and wound healing for related concepts.

Applications by specialty

Absorbable sutures are widely used across surgical disciplines: - General and abdominal surgery: closure of serosa and subserosal layers, and internal mucosal closures. - Obstetrics and gynecology: uterine and pelvic tissue closures where long-term foreign material is undesirable. - Otolaryngology and head-and-neck: mucosal or submucosal closures where rapid re-epithelialization is beneficial. - Ophthalmology: delicate, rapidly absorbing materials for intraocular or ocular surface work, where prolonged foreign material can be problematic. - Plastic and reconstructive surgery: deep tissue closures or layered repairs where controlled strength duration aids proper healing.

See surgical suture and specific tissue-related pages for more context and material recommendations.

Safety, risks, and complications

As with any implantable material, absorbable sutures carry potential risks: - Foreign body reaction and granuloma formation: more likely with natural materials or braided synthetic sutures in certain contexts. - Local inflammation: especially with catgut or poorly matched materials, which may prolong healing or cause discomfort. - Infection risk: any implanted suture can harbor bacteria if contamination occurs; the suture’s longevity can influence the duration of exposure. - Suture line failure or dehiscence: inadequate tensile strength or improper technique can lead to wound separation, particularly in high-tension areas. - Allergic or hypersensitivity reactions: rare but possible with certain polymers or additives.

Quality and sterility are tightly regulated through manufacturing standards and regulatory oversight. In the United States, absorbable sutures are subject to FDA review and clearance or approval, while in the European Union they may bear CE marking, reflecting conformity with applicable safety and performance requirements. See FDA and CE marking for regulatory context.

Manufacturing, quality control, and regulation

Manufacturers emphasize consistent fiber dimensions, sterilization methods, and accurate labeling of absorption timelines and tensile properties. Standards organizations and regulatory agencies require thorough testing, including mechanical strength, biocompatibility, and sterility, before products reach the clinic. Ongoing post-market surveillance informs updates to recommendations and material improvements. See Quality control and biocompatibility for related topics.