What Is a Chromic Suture?

A chromic suture is a surgical suture that is treated in an acid bath to help it resist breakdown by bodily enzymes so that it will last longer in the body before eventually being absorbed. These sutures are made with a collagen base that the body could otherwise readily break down, which is not desirable at all surgical sites. Surgical suppliers sell a variety of sizes and lengths of chromic sutures, some of which might come attached to disposable needles for convenience in the operating room.

The collagen base for these sutures usually comes from cow or sheep intestines. The manufacturer processes the intestines until they are mostly pure collagen, then exposes them to chromium salts. Depending on the salt mixture and how long the material stays in the acid bath, the breakdown rate can vary. Some products might last as long as 40 days in the body before they start to break down in response to the enzymes produced by the patient's body.

A surgeon might select a chromic suture if there is a need for an absorbable suture, and he or she can choose the most appropriate grade for the site. For some surgeries, the stitches might need to last only two to three weeks, but others might call for more durable sutures. Initially, the chromic sutures will retain their tensile strength and flexibility, allowing the patient to bend and flex without snapping or cutting off circulation to the tissue around the surgical site. As the sutures start to break down, they can become more brittle.

Typically, medical suppliers package a chromic suture in a sterile, single-use packet. A surgeon can determine which needle is necessary and how long the suture should be, and an assistant will select and open the correct package. Needle and suture selection depend on the type of injury and the surgeon's preferences. Plastic surgeons, for example, tend to prefer very fine sutures to minimize scarring, and other surgeons might opt for heavier sutures to resist stress at sites such as the abdomen.

Packing for a chromic suture should indicate that it is sterile and provide information about its lot number and date of production. If a doctor has doubts about a suture, it can be discarded in lieu of a fresh package. Doctors who note adverse reactions to sutures might report them to the manufacturers if they have concerns about contamination.

Patients who are preparing for surgery or any procedure that requires stitches should be aware that sutures can contain potential allergens or substances that might be sources of religious or ethical objection. A chromic suture, for example, can include cow intestines, which might be offensive to Hindu or Buddhist patients. Patients who have concerns about products that might be used can discuss these issues with their care providers or religious officiants, if applicable. Many religious officiants agree that exceptions for medical necessity are reasonable if a normally banned product is the best choice for the patient's needs.