It is common for dissolving stitches to remain visible or intact long after they were expected to disappear. While this can cause concern, delayed dissolution is usually not a sign of a serious complication. Absorbable stitches are designed to support the healing wound for a specific period, but the process is highly variable based on biological factors and the material used. Understanding how these temporary medical devices work can help alleviate anxiety about their lingering presence.
Understanding Absorbable Sutures
Absorbable sutures are surgical threads made from materials the body naturally breaks down and eliminates. These materials fall into two main categories: natural fibers (like catgut) or, more commonly today, synthetic polymers (such as polyglycolic acid or polydioxanone). The primary advantage of using these materials is that they eliminate the need for a follow-up appointment to have the stitches manually removed.
The body uses distinct biological processes to dissolve these materials. Synthetic sutures primarily break down through hydrolysis, a predictable chemical reaction where water molecules gradually cleave the polymer chain’s bonds. Natural sutures are absorbed by enzymatic degradation, a less predictable process involving the body’s own enzymes. Depending on the material chosen, total absorption time ranges from a few weeks for fast-absorbing materials to several months for products designed to provide longer-term support.
Reasons for Delayed Dissolution
The manufacturer-specified absorption time represents an average, and several factors can slow down the process. A primary reason is the intentional longevity engineered into certain suture materials chosen by the surgeon. For instance, a deep internal closure may use a material designed to maintain strength for six weeks and not fully disappear for over 180 days to ensure tissue stability.
Patient-specific factors, such as overall metabolism and underlying health conditions, also play a significant role. Individuals with chronic illnesses, like diabetes, or those who are immunocompromised may experience a slower healing cascade, which indirectly delays absorption. Furthermore, the environment around the stitch matters; areas with lower localized blood flow (vascularity) can slow the rate of hydrolysis because the necessary water molecules and metabolic activity are less readily available.
Recognizing Signs of Suture Extrusion or Reaction
When stitches persist past their expected timeframe, it may indicate the body is reacting to the foreign material. This reaction is often termed “suture spitting” or extrusion, where the immune system pushes the material toward the skin surface instead of absorbing it internally. This localized inflammatory attempt to expel the stitch may appear as a small, firm piece of thread poking out through a healed incision line.
Another possible sign is the formation of a foreign body granuloma, which feels like a small, firm bump or nodule beneath the skin around the suture site. This occurs when immune cells surround the unabsorbed material to wall it off, effectively encapsulating the stitch in scar tissue. While these reactions are not usually infections, they can cause persistent localized inflammation, leading to redness or mild tenderness.
Necessary Actions and Medical Intervention
If you notice a stitch that has not dissolved, first consult the expected timeline provided by your medical team. If the stitches remain visible or palpable weeks after the longest expected dissolution window, schedule a medical evaluation. You must avoid attempting to pull, pick at, or remove the exposed suture material yourself, as this can introduce bacteria, leading to infection or causing the wound to reopen.
Seek medical attention immediately if the persistent stitch is accompanied by signs of infection.
Signs of Infection
- Increasing pain
- Spreading redness
- Warmth around the wound
- Presence of pus or foul-smelling discharge
A healthcare provider can quickly determine if the lingering stitch is simply an unabsorbed knot or the sign of a deeper issue. Intervention is usually a straightforward, painless in-office procedure where a clinician uses sterile instruments to snip the exposed thread and gently remove the remaining material.