Dissolvable stitches, formally known as absorbable sutures, are medical devices designed to temporarily hold tissues together following surgery or injury. These specialized threads are made from materials that the body can naturally break down and metabolize over time. Their defining benefit is the elimination of a second procedure, as the patient does not need to return to a healthcare provider for stitch removal. This ability to disappear makes them particularly useful for closing internal wounds or for use in patients who might have difficulty with follow-up appointments.
The Early History and Need for Absorbable Materials
For centuries, surgeons relied on non-absorbable materials like silk, linen, and horsehair to close wounds, which required a subsequent procedure for removal. Early attempts at creating an absorbable thread centered on the use of catgut, a material derived from the purified collagen of animal intestines, usually sheep or cattle. The use of gut strings as a suture material dates back to ancient times, with the Greek physician Galen reportedly using them in the second century AD.
Catgut presented numerous challenges that limited its reliability. Its absorption rate was highly inconsistent, varying significantly, which could lead to premature wound failure or prolonged irritation. Because catgut is a natural material, it was broken down by enzymatic processes, often triggering an inflammatory response. A major breakthrough came in 1860 when Joseph Lister developed a method to sterilize catgut using carbolic acid, which reduced the high rates of infection associated with early materials.
The Definitive Invention Timeline of Synthetic Sutures
The revolution in absorbable sutures came with the shift to synthetic polymers, offering a predictable and consistent degradation profile. This foundational change began in the mid-20th century with the discovery of synthetic fibers in other industries. The first synthetic absorbable polymer developed for surgical use was polyglycolic acid (PGA), introduced in the late 1960s.
The first commercially available synthetic absorbable suture was Dexon®, launched by Davis & Geck in 1971, utilizing polyglycolic acid (PGA). This introduction significantly reduced the reliance on catgut, which was known for causing wound irritation and inconsistent strength properties. Following this innovation, Ethicon introduced a similar product, Vicryl®, a co-polymer of polyglycolic acid and polylactic acid.
These first-generation synthetic sutures addressed the problems of catgut by offering more controlled strength and absorption, breaking down through a chemical reaction rather than an enzymatic one. In 1982, the first monofilament synthetic absorbable suture, PDS® (polydioxanone), was released by Ethicon. PDS was designed to provide longer-lasting support for slower-healing tissues like fascia.
How Absorbable Stitches Dissolve
Modern synthetic absorbable sutures dissolve through hydrolysis, a chemical process that ensures a slow and predictable breakdown. Hydrolysis involves water molecules penetrating the suture material and gradually breaking the chemical bonds of the polymer chains. This process is distinctly different from enzymatic degradation, which tends to be less predictable and cause more inflammatory reaction.
As the polymer chains break down, the thread gradually loses its tensile strength, meaning it can no longer hold the wound edges together. Once structural integrity is lost, the material disintegrates into harmless components that the body can safely metabolize and excrete. The composition of the synthetic polymer determines the absorption rate, allowing for sutures with varied timelines for different surgical needs.
Materials like polyglycolic acid (PGA) and polyglactin (a PGA co-polymer) are designed for fast absorption, typically losing strength within two to three weeks and fully dissolving within 60 to 90 days. Conversely, polymers such as polydioxanone (PDS) are engineered to maintain their strength for a longer period, sometimes up to six weeks, making them suitable for tissues that heal more slowly.