Internal stitches, also known as sutures, are specialized medical threads used by surgeons to hold deeper layers of tissue together after an operation. These materials provide mechanical support while the body heals and regenerates new tissue. The concern about internal stitches appearing on the surface is a common post-operative question related to how the body interacts with foreign objects during recovery. This article explains why this phenomenon occurs and when it requires professional medical attention.
Distinguishing Absorbable and Non-Absorbable Sutures
The behavior of an internal stitch depends on its material, determining whether it is absorbable or non-absorbable. Absorbable sutures are constructed from synthetic polymers or natural materials such as purified catgut. The body gradually breaks down and dissolves these materials through hydrolysis, a chemical reaction involving water. This type of suture loses its tensile strength over several weeks or months before disappearing completely from the tissue.
Non-absorbable sutures are typically manufactured from durable materials such as nylon, silk, or polypropylene. These threads are permanent and are not intended to be metabolized or broken down by the body. In deep tissue layers, non-absorbable materials remain permanently to provide long-term structural support. If placed close to the skin’s surface, they may need manual removal once the wound has healed sufficiently.
Why Internal Stitches Extrude or “Spit”
The process of an internal stitch coming to the surface is medically termed suture extrusion. Extrusion occurs because the body recognizes the suture material, whether absorbable or not, as a foreign object within the tissue. This recognition triggers a localized inflammatory response, which is part of the normal immune system function. Specialized cells surround the suture material in an attempt to isolate and remove the invader.
The body attempts to expel this foreign material through the path of least mechanical resistance, often the original surgical tract or incision line. As the deeper layers of the wound contract and heal, pressure can push a small segment of the suture toward the skin. This can happen weeks or months after surgery, long after the outer skin layer appears fully closed. The appearance can be a small, stiff piece of thread, a tiny knot, or a loop poking through the healed skin.
The extruded stitch is generally sterile and represents a normal part of the healing process. If only a small piece is visible, it may continue to be pushed out until it naturally falls away. Healthcare providers often instruct patients that if a short thread is exposed, they can gently trim the visible portion close to the skin with sterilized scissors. Care must be taken not to pull the stitch out or disturb the wound.
Determining When Medical Attention is Necessary
While stitch extrusion is often a normal event, certain accompanying signs indicate that professional medical evaluation is necessary. The appearance of a stitch should not be accompanied by increasing pain or swelling around the surgical site. These symptoms can be markers of an underlying complication or an infection that requires prompt treatment.
Specific signs of a localized infection include spreading redness and warmth radiating outward from the incision. Immediate medical attention is required if there is a foul odor or the drainage of thick, yellowish, or greenish pus from the site. Patients should also contact their healthcare provider if they develop a fever, which is a systemic sign of a potential infection.
Urgent medical review is required if the wound edges pull apart significantly, a condition known as wound dehiscence. Similarly, if the extruded stitch is large, continuous, or cannot be easily managed with a simple trim, a doctor or nurse should assess the site. Timely intervention can prevent minor issues from progressing into more serious complications and ensure the continued integrity of the healing wound.