If you have had a procedure using absorbable stitches, it is common to worry when they remain visible longer than expected. Absorbable sutures are specialized medical threads designed to provide temporary support to a healing wound before the body naturally breaks them down. This dissolution process is gradual, depending on a complex biological interaction between the suture material and your body’s tissues. Understanding the normal timelines and reasons for delay can help determine if your experience is part of normal healing or requires medical attention.
Understanding Absorbable Sutures
Absorbable sutures are made from materials the body can metabolize, meaning they do not require removal. These materials disappear through either hydrolysis or enzymatic degradation, depending on the suture type. Synthetic sutures, such as polyglycolic acid, break down primarily through hydrolysis. This chemical reaction involves water molecules penetrating the suture polymer, slowly breaking the chemical bonds and reducing its tensile strength until it fully disintegrates.
Natural sutures, such as those made from animal-derived collagen like catgut, rely on enzymatic degradation. The body’s own enzymes attack and metabolize the suture material over time. Even if the thread is visible, the material is actively losing strength and being processed by the body. This is a key distinction from non-absorbable stitches, which remain intact until they are manually removed.
Normal Dissolution Timelines
The time it takes for an absorbable suture to fully disappear is highly variable and depends on the specific material chosen by the surgeon. This selection is deliberate, based on how long the tissue requires support to heal properly. Fast-absorbing sutures, often used for delicate or mucosal tissues, may lose strength rapidly and be fully absorbed in approximately 42 to 60 days.
Conversely, materials designed for deeper layers or areas needing extended support take much longer to dissolve completely. For example, sutures like Polydioxanone (PDS) may maintain their presence for up to 200 days before absorption is complete. Since absorption is a process, not an event, a wound may be healed externally while internal stitches are still gradually dissolving over several weeks or months.
Factors Leading to Delayed or Non-Dissolution
When stitches seem to be lingering, the cause is often a combination of material type and local tissue response. Sometimes, knot extrusion occurs, where the body attempts to push a buried knot or a short piece of suture material out through the skin surface. This exposed thread is no longer fully submerged in tissue fluid and can appear to stop dissolving, even if the submerged portion is gone.
The suture material itself contributes to variability, as modern synthetic polymers are designed to be durable and can take longer than expected to disappear. The area of the body where the suture is placed also plays a role. Tissues with lower blood flow or areas under constant movement may slow the rate of hydrolysis. A localized inflammatory response, sometimes called a foreign body reaction, can also wall off the material, delaying its breakdown.
The presence of infection can disrupt the normal healing environment. While infection sometimes speeds up the breakdown of certain materials like catgut, a localized infection or abscess around the stitch can complicate the material’s resolution and cause it to persist longer than anticipated. Ultimately, the apparent delay often means the chosen material is one of the slower-absorbing types, or the body is simply taking its time to process the foreign substance.
Recognizing Signs of Complication
While a slow-dissolving stitch is often normal, certain signs indicate a complication may be developing and require immediate medical attention. The most serious concern is infection, which is signaled by symptoms that worsen instead of improve after the first few days post-procedure. Look for spreading redness or warmth extending significantly away from the incision line, severe or escalating pain, and the presence of pus or foul-smelling discharge. A high fever or chills are also signs of a systemic infection that needs immediate evaluation.
A different complication is a suture reaction or allergic response, which may present as intense, persistent itching or swelling that extends beyond the expected area of inflammation. Although it may mimic infection, an allergic reaction is the body overreacting to the suture material itself, sometimes resulting in clear fluid drainage. If a visible stitch is causing significant discomfort, or if you observe any of these concerning symptoms, contact your surgical team or healthcare provider immediately. Never attempt to cut or pull out a visible stitch yourself.