Absorbable sutures, often called dissolvable stitches, are a common tool used by medical professionals to close wounds following surgery or injury. These specialized materials eliminate the need for a follow-up appointment solely for suture removal, making the healing process more convenient. They are designed to provide temporary support to tissue until the body’s natural healing mechanisms are strong enough to hold the wound closed permanently. However, sutures sometimes remain long after their expected disappearance date, failing to dissolve as anticipated.
How Absorbable Sutures Normally Dissolve
The process by which absorbable sutures dissolve is a controlled biological and chemical reaction. Synthetic absorbable sutures, the most common type used today, primarily break down through hydrolysis. This process involves water molecules from the body’s tissues penetrating the polymer chains of the suture material, slowly breaking the chemical bonds. This gradual breakdown reduces the material into smaller fragments, which the body can then metabolize and eliminate.
Natural absorbable sutures, such as those made from purified collagen (like catgut), use enzymatic degradation. The body’s proteolytic enzymes attack the material, effectively digesting the protein structure. Because this enzymatic action can sometimes trigger a stronger inflammatory response, synthetic materials are often preferred for their more predictable breakdown. The time required varies significantly based on the material, ranging from a few weeks for fast-absorbing sutures to up to six months for slower materials like Polydioxanone (PDS).
Factors That Can Cause Suture Retention
When a suture fails to dissolve within its expected timeline, it is usually due to environmental or biological factors that interfere with the normal breakdown processes. The specific location where the suture is placed plays a significant role. Areas with low blood flow (vascularity) tend to slow down the absorption rate, meaning sutures in the face may dissolve more quickly than those in less perfused tissue. External knots or exposed portions are also often slower to disappear than internal segments, as they are not fully immersed in the body’s metabolically active environment.
Individual biological variation also influences the speed of absorption. Factors such as the patient’s overall metabolic rate, age, and underlying health conditions (like diabetes or a compromised immune system) can affect the body’s ability to process the material efficiently. Another element is the original material choice by the surgeon. Using a material designed for extended support, like PDS, naturally results in a much longer retention time than a rapid-absorbing material.
Signs of Complication and When to Contact a Doctor
A retained suture is only problematic if it begins to cause complications, which usually stem from the body treating the material as a persistent foreign object. The most common complication is a localized infection, characterized by increasing redness, swelling, warmth, and pain at the surgical site. The presence of pus or unusual discharge suggests bacteria have colonized the suture, which acts as a scaffold for infection.
Sometimes, the body attempts to physically push the foreign material out, a process known as “spitting sutures.” This manifests as a small, firm knot or loop extruding through the skin surface, which can cause irritation or chronic inflammation. While minor inflammation is part of healing, immediate contact with a healthcare provider is warranted if the redness spreads rapidly, a fever develops, or the pain becomes severe. These symptoms signal a potential systemic issue or an abscess forming that requires professional evaluation.
Treatment Options for Retained Sutures
The management of retained absorbable sutures depends on whether the material is causing symptoms or complications. If a suture is retained but is not causing pain, redness, or discharge, the healthcare provider may choose to simply monitor the area. In many mild cases, the material will eventually be absorbed or extruded by the body without intervention.
If the retained material is accessible, visible, and causing localized irritation, the solution is often a simple manual removal. A healthcare provider can use sterile instruments to snip and gently pull the exposed material free. If an infection or significant inflammation is present, treatment requires removing the suture to eliminate the bacterial focus, followed by a course of antibiotics. This intervention is usually a minor procedure performed in a clinic setting.