Absorbable sutures are a common medical tool used to close wounds following surgical procedures or injuries. These stitches are designed to be metabolized by the body over time, which eliminates the need for manual removal during a follow-up appointment. They are frequently used for internal closures, such as in muscle or deeper tissue layers, or for external skin closures. When these sutures fail to dissolve as intended, the body’s healing process may be affected, leading to complications.
How Dissolvable Stitches Work
The mechanism by which absorbable stitches disappear depends on the material they are made from, utilizing either hydrolysis or enzymatic degradation. Most modern synthetic sutures, such as those made from polyglycolic acid (PGA) or polydioxanone (PDS), are broken down through hydrolysis. This is a predictable chemical process where water molecules in the body’s tissues slowly break the polymer chains of the suture material into smaller, absorbable components. Natural sutures, like catgut, rely on enzymatic degradation, where the body’s own enzymes attack and break down the material. The time it takes for full dissolution varies widely, ranging from a few weeks to several months. For instance, fast-absorbing materials may be gone in 10 to 21 days, while PDS sutures, used for deep tissues requiring long-term support, can take up to 210 days to fully absorb.
Recognizing Signs of Delayed Absorption
A primary indication that absorbable sutures are not dissolving is the visible presence of the material long after the expected healing time frame has passed. If the suture material or external knot remains visible on the skin’s surface for many weeks, it suggests a delay in the breakdown process. Patients may also experience persistent, mild tenderness or irritation directly at the incision site. Sometimes, the body’s reaction causes a small, firm bump or nodule to form along the suture line, which may be felt just beneath the skin. This is often accompanied by localized redness that does not fade over time. If the stitches start to poke through the skin, known as suture spitting, it is a clear sign that the material is being extruded rather than absorbed.
Factors Hindering Dissolution and Potential Complications
When dissolvable stitches do not dissolve, it is often because the local biological environment of the wound has been altered. An infection at the surgical site can significantly hinder the absorption process by changing the tissue’s pH and inflammatory response. The sustained presence of bacteria and inflammatory cells interferes with the chemical breakdown of the suture material. Another common issue is a localized foreign body reaction, where the immune system recognizes the suture material as an invader. This can lead to the formation of a granuloma, a localized mass of inflammatory tissue that encapsulates the retained material. When a suture is placed too superficially under the skin, it may be exposed to air or surface moisture, causing the material to break down unevenly or fail to absorb entirely. The body may then attempt to force the material out, resulting in suture spitting and increased irritation.
When to Seek Medical Attention and Treatment
If a patient observes that the suture material is still present well beyond the timeframe specified by their medical provider, it is wise to contact the doctor for guidance. More concerning signs that require immediate medical attention include an increase in pain, spreading redness, swelling, or any discharge from the wound site. The presence of fever or a foul odor can indicate a serious infection that needs prompt treatment. For sutures that are simply retained or protruding, the treatment is usually straightforward and performed in an office setting. A provider can address suture spitting by simply trimming the exposed thread at the skin line. If a small granuloma has formed around the material, a minor procedure may be necessary to remove the retained stitch entirely, which resolves the body’s inflammatory reaction. The wound is almost always healed by the time delayed dissolution becomes an issue, meaning removal of the stitch will not compromise the closure.