Sutures, commonly known as stitches, are medical devices used to hold body tissues together following an injury or surgical incision. Their primary function is to approximate the edges of a wound, maintaining close contact to facilitate natural healing and minimize scar formation. Applying stitches is a precise medical technique requiring professional training, knowledge of wound mechanics, and a sterile environment. The process involves preparation, application, and post-application care.
Pre-Suture Assessment and Preparation
Before closure, a medical professional must evaluate the wound to determine if suturing is appropriate. Sutures are generally necessary for deep wounds, lacerations with gaping edges, or injuries crossing areas of high movement like joints. Superficial wounds may be closed using less invasive options such as adhesive strips or medical tissue glue. The optimal window for primary closure is typically within six to eight hours of injury to reduce the risk of bacterial proliferation.
Assessment includes examining the wound for foreign debris and determining the extent of tissue damage. Meticulous wound care involves irrigation to flush out contaminants and loose cellular material using a sterile solution, often normal saline. The solution is delivered at a pressure of four to fifteen pounds per square inch (psi) to cleanse effectively without causing further tissue trauma. Debridement, the removal of non-viable or heavily contaminated tissue, may be performed to ensure the remaining wound bed is healthy for healing.
Pain management is addressed using a local anesthetic, commonly Lidocaine, to thoroughly numb the area before the procedure. The professional injects the solution into the subcutaneous fat layer beneath the wound. The anesthetic is injected slowly as the needle is withdrawn to create a uniform field of numbness around the laceration. This technique blocks nerve signals at the injection site, making the subsequent manipulation and closure of the wound painless.
Essential Tools and Suture Materials
Closing a wound requires specific instruments designed to handle delicate tissue and manipulate the curved needle. The needle driver, or needle holder, grips and guides the needle through the tissue layers with precision. It features a locking mechanism and jaws, often reinforced with tungsten carbide, to maintain a secure hold without damaging the needle. Tissue forceps, such as toothed forceps, gently grasp the skin edges during the procedure, providing counter-tension and ensuring correct alignment.
The third primary tool is the suture scissors, designed to cut the suture material cleanly once a knot is secured. The suture consists of a needle permanently attached to a thread-like material, known as a swaged needle and thread. Suture threads fall into two categories: absorbable and non-absorbable. Absorbable sutures, such as Polydioxanone (PDS), are broken down by the body over time through hydrolysis or enzymatic action, eliminating the need for later removal.
Non-absorbable materials, like Nylon or Silk, resist breakdown and are used for exterior skin closure or areas requiring long-term support, necessitating manual removal once the wound heals. The needle component is chosen based on the tissue type. Skin, a tough and fibrous tissue, requires a cutting needle, typically a reverse cutting type, designed to slice cleanly through the epidermis. Softer tissues, such as internal organs, are closed with tapered needles that have a round body and spread tissue fibers apart.
Standard Techniques for Wound Closure
The most fundamental method for skin closure is the Simple Interrupted Suture, where each stitch is placed, tied, and cut individually along the wound. This technique allows for excellent control over the tension of each stitch and provides security, as the failure of one knot does not compromise the rest of the closure. The needle is loaded into the driver approximately one-third of the way from the swaged end to maximize control and leverage.
The needle is driven into the skin at a ninety-degree angle, typically a few millimeters from the wound edge, ensuring it passes through an equal amount of tissue on both sides and at an equal depth. Maintaining this perpendicular entry angle is important because it causes the wound edges to evert slightly, ensuring they meet cleanly and promoting a better cosmetic outcome. The surgeon uses the natural curvature of the needle, turning the wrist to allow the needle to follow its arc through the tissue, minimizing drag and trauma.
After the needle exits the opposite skin edge, an instrument tie secures the suture. This is done by wrapping the long end of the suture material around the needle driver, grasping the short end with the instrument’s tip, and pulling the ends in opposite directions to form the first throw of the surgical knot. The knot is tightened only enough to bring the wound edges into gentle contact (approximation), without strangulating the tissue. Overly tight knots restrict blood flow, compromising the healing process.
A square knot is formed by alternating the direction of the wraps on subsequent throws; typically three to four throws are used to ensure security. While the Simple Interrupted Suture is the standard, a running or continuous suture may be used for long, straight lacerations with minimal tension. The continuous technique is faster to place but relies on the integrity of a single line of stitching, meaning failure at any point risks the entire closure coming undone.
Post-Application Care and Removal
Once the final stitch is placed, post-application care focuses on protecting the wound and monitoring for complications. The sutured wound is immediately covered with a sterile dressing, and the patient must keep the area completely dry for the first twenty-four hours. After this initial period, brief showering is usually permitted, but the site must be gently patted dry immediately afterward. Soaking the wound in a bath or pool is prohibited until the sutures are removed. Patients should avoid activities that place excessive strain on the wound, which could cause the closure to separate (dehiscence).
Post-suture care involves watching for signs of infection, which require immediate medical attention. These signs include:
- Increasing redness spreading beyond the wound edges.
- Swelling.
- Excessive warmth at the site.
- A persistent discharge of pus.
A fever or sudden increase in pain not alleviated by normal medication is also a warning sign that the healing process has been compromised.
The timeline for removing non-absorbable sutures depends on the anatomical location, reflecting varying rates of healing and skin tension. Sutures on the face, which has a rich blood supply and heals quickly, are often removed within three to five days to prevent noticeable track scars. Wounds on the trunk typically require seven to ten days of support. Sutures over high-tension areas like the extremities, hands, or joints may need to remain in place for ten to fourteen days to ensure adequate tensile strength has returned to the tissue.