Catgut sutures are a type of medical material used for wound closure. They are natural and absorbable by the body over time. For centuries, catgut has been a reliable method for bringing tissues together, especially in internal surgeries where suture removal isn’t possible. Its properties have made it a longstanding tool in medicine.
Unraveling the “Cat” Myth
The term “catgut” often leads to the misunderstanding that they are derived from cats. This is a myth. The name’s origin is believed to be linguistic, not literal. One theory suggests “catgut” comes from a mispronunciation of “kitgut,” referring to strings for musical instruments like violins, where “kit” was an old term for a small fiddle. Another theory is that it’s a shortened form of “cattlegut,” indicating its animal origin from livestock.
The True Origin and Processing
Catgut sutures are made from purified collagen in the small intestines of ruminant animals like sheep or goats. Sometimes, intestines from hogs, horses, mules, pigs, donkeys, or beef tendons are also used. The manufacturing process begins by cleaning the intestines and removing fat. The material is then steeped in water and scraped to remove external membranes.
Next, the cleaned tissue is treated with an alkaline lye, smoothed, and stretched. The strands are twisted together to form a suture thread. To enhance smoothness and pliability, they may be polished and packed in an alcohol solution. Finally, the sutures are sterilized, typically using ethylene oxide, isopropyl alcohol, and distilled water, to ensure safety.
Key Characteristics and Modern Use
Catgut sutures are absorbable, meaning the body’s enzymes naturally break them down over time. Plain catgut sutures lose tensile strength within about 7 days and are absorbed within 60 to 70 days. Chromic catgut, treated with chromium salts, offers extended wound support, retaining tensile strength for 18 to 21 days and absorbing around 90 days. This treatment also reduces tissue irritation.
Historically, catgut was widely used in various surgical procedures, including general closure, ophthalmic, orthopedic, obstetrics/gynecology, and gastrointestinal surgeries. While synthetic absorbable sutures like Vicryl and polydioxanone have largely replaced catgut in many applications due to concerns about potential disease transmission and more predictable absorption, catgut still finds specific uses in modern medicine. Its natural absorption makes it suitable for rapidly healing tissues or where a natural, absorbable material is preferred.