Mohs micrographic surgery is a highly precise technique for removing common types of skin cancer while preserving the maximum amount of healthy tissue. Following the removal of cancerous cells, the resulting wound must be closed. Surgeons frequently rely on internal, absorbable stitches for optimal healing and cosmetic outcomes, eliminating the need for a second procedure to remove them.
Understanding Absorbable Sutures in Mohs Closure
Absorbable sutures are manufactured from synthetic polymers, such as polyglactin, polydioxanone, and polyglycolic acid, that the body can naturally break down. These stitches are placed deep beneath the skin’s surface to hold the wound edges together while deeper tissues regain strength. Securing the inner layers reduces tension on the outermost skin, which helps minimize scarring.
The sutures dissolve through hydrolysis, a chemical reaction where water molecules penetrate the polymer chains. This interaction breaks the material down into smaller, biologically compatible molecules that the body absorbs and eliminates. This process is more predictable and less inflammatory than the enzymatic degradation used for older, natural sutures. The choice of material is selected based on the tissue type and the anticipated time required for the wound to heal.
The Dissolution Timeline
The time it takes for absorbable stitches to fully dissolve is highly variable, ranging from a few weeks to several months, depending on the suture material selected. For deep layers closed after Mohs surgery, which require sustained support, total absorption often takes three to six months. For instance, Polyglactin 910 may take 60 to 90 days to be completely absorbed, while Polydioxanone is designed to last longer, sometimes taking up to 240 days.
The time it takes for the stitch to lose its holding strength is much shorter than the time for it to disappear completely. A polyglactin suture may lose most tensile strength within two to three weeks, which is the timeframe needed for the wound to establish initial strength. Once the wound is healed, the suture’s mechanical role is finished, and the slower process of full mass absorption begins. Visible knots or ends on the skin surface typically fall off much sooner, often within the first few weeks.
Factors Influencing Dissolution Speed
Several variables influence the dissolution timeline. The inherent design of the suture is the primary factor, as polymers are engineered for specific absorption rates to match tissue healing speed. Thicker sutures (higher gauge) contain more material and take longer to break down compared to thinner ones made from the same polymer.
The wound location also plays a significant role in dissolution speed. Sutures placed in highly vascular areas, such as the head and neck (common Mohs sites), may dissolve faster due to increased blood flow and metabolic activity. Conversely, wounds in areas with less circulation experience a slower absorption rate. A patient’s overall health and metabolic rate can also alter the rate at which the body processes the foreign material.
Monitoring the Healing Process
As internal stitches begin to break down, patients may observe small, flaky pieces of suture material, or visible knots may fall away from the incision line. These are normal signs of the dissolution process. Sometimes, the body may expel a stitch before it is fully dissolved, an event called a “spitting suture.” This can look like a small white thread emerging from the wound or a pimple-like bump. If this happens, a healthcare provider can easily trim the exposed material, but patients should never pull or pick at the stitch ends themselves.
Minor itching or redness is common during healing, but certain signs warrant immediate medical contact to check for complications.
Signs Requiring Medical Evaluation
- Persistent or increasing redness, warmth, or excessive swelling.
- The presence of pus or foul-smelling drainage from the wound.
- Failure of deep stitches to dissolve long past the expected three-to-six-month period.
- Any sudden increase in pain.
Careful observation and adherence to post-operative care instructions ensure the wound heals properly.