Suturing is a technique of wound closure that uses a needle and thread to hold damaged tissues together, allowing the body’s natural healing processes to occur. The primary goal of this procedure is to promote rapid and complete healing by carefully approximating the wound edges, which also helps to minimize the resulting scar. This article provides a detailed, step-by-step educational breakdown of the suturing process. However, suturing is a medical procedure that carries risks and must only be performed by trained medical professionals in a sterile setting.
Essential Tools and Materials
Suturing requires a specialized set of instruments designed for precision and tissue handling. The needle driver (or needle holder) is a specialized clamp used to securely grasp and manipulate the curved needle through the tissue. Surgical forceps, often with fine teeth, gently hold and stabilize the wound edges for accurate needle placement. Suture scissors are required to cut the material after the knot is tied; they are designed with a blunt tip to safely slide under the thread without damaging the underlying skin.
Suture material is categorized as either absorbable or non-absorbable based on its fate in the body. Absorbable sutures are broken down by the body over time, typically used for closing deep tissue layers, and do not require later removal. Non-absorbable materials, such as nylon or polypropylene, remain until manually removed and are commonly used for skin closure. The attached needle is usually curved, often featuring a reverse cutting tip to penetrate tough skin with minimal trauma.
Preparing the Wound Site
Before closure, a detailed assessment determines if suturing is appropriate. This involves noting the wound’s location, depth, contamination, and involvement of underlying structures like nerves or tendons. Hemostasis, or stopping active bleeding, must be achieved first, often by applying direct pressure or elevation. Closure should only proceed once bleeding is fully controlled.
Wound cleansing and irrigation significantly reduce the risk of infection. The wound cavity is flushed thoroughly with a high volume of sterile saline solution or clean water to physically remove foreign debris and bacteria. Irrigation must be performed with sufficient pressure (typically 8 to 15 psi) to dislodge contaminants without forcing bacteria deeper into the tissue. The surrounding skin is prepared with an antiseptic solution, but harsh chemicals are avoided within the wound itself as they can damage cells and impair healing.
Local anesthesia is administered to numb the area and ensure patient comfort. Lidocaine is a common agent, injected using a small needle into the tissue surrounding the wound, not directly into the wound bed. To reduce stinging, the anesthetic can be warmed or buffered with sodium bicarbonate, and the injection should be performed slowly as the needle is withdrawn. This technique ensures the anesthetic is distributed along the planned path, allowing for a pain-free closure.
Executing the Simple Interrupted Suture Technique
The simple interrupted suture is the widely used technique for closing skin wounds, as each stitch is placed and tied independently, controlling tension. The process begins with the needle driver holding the needle securely approximately two-thirds of the distance from the tip. This positioning optimizes the leverage needed to pass the needle through the tough layers of the skin.
The needle is inserted into the skin at a 90-degree angle, typically five to ten millimeters away from the wound edge. Maintaining this perpendicular angle ensures the suture encompasses the full thickness of the dermis and promotes eversion of the skin edges. Eversion, where the edges slightly roll outward, prevents the development of a depressed scar when the wound contracts during healing.
As the needle is driven through the tissue, the wrist is rotated to follow the natural arc of the needle’s curvature, creating a path that resembles an Erlenmeyer flask shape beneath the skin. This shape helps bring the deeper layers together and pushes the superficial edges outward. The needle must exit the tissue on the opposite side at a point equidistant from the wound edge and at the same depth as the entry point, guaranteeing equal tissue “bites” and balanced tension. Unequal bites can result in a visible step-off deformity.
Once the suture material is passed through both sides, leaving a short tail, the instrument tie secures the stitch. The knot is initiated by wrapping the long end of the suture around the needle driver twice (a double-throw), which provides friction to hold the initial tension. The needle driver then grasps the short end, and the hands are crossed to pull the short end through the loop, laying the first throw flat against the skin surface.
The second throw is a single wrap in the opposite direction from the first, completing a secure square knot that will not easily loosen. For most non-absorbable skin sutures, three to four alternating single throws are placed to ensure the knot is stable. The knot must be tightened only enough to gently approximate the skin edges, causing them to “kiss” together. Overtightening causes the skin to blanch, indicating tissue strangulation and potential tissue death. Finally, the suture tails are cut, leaving approximately one centimeter of thread beyond the knot to facilitate removal.
Post-Suture Care and Removal
Proper care of the sutured wound prevents infection and optimizes the final cosmetic result. For the first twenty-four to forty-eight hours, the wound must be kept clean and dry to allow the initial seal to form. Afterward, gentle washing with mild soap and water is permitted, but the area should not be soaked or submerged until the sutures are removed. Patients must limit activities that place excessive strain or tension on the repair site.
Patients should monitor the wound for signs of surgical site infection, which warrant immediate medical attention:
- Increasing pain or tenderness.
- Excessive redness that spreads outward from the wound.
- A feeling of warmth at the site.
- The presence of thick, yellow or green drainage (pus).
Non-absorbable sutures are removed when the wound has achieved sufficient tensile strength, typically between three and fourteen days. Timing varies significantly by body location; facial sutures may be removed as early as three to five days, while those on the back or extremities may remain for ten to fourteen days. The removal process begins by cleaning the wound site with an antiseptic solution to remove surface crusting.
Using a pair of forceps, the knot of the suture is gently grasped and lifted away from the skin surface. Suture scissors are then used to cut the thread on one side, specifically in the segment that was beneath the knot and closest to the skin. This ensures that the exposed, contaminated portion of the thread is not pulled through the healing tissue. The forceps then gently pull the knot and the entire strand of suture material smoothly out of the skin. Following removal, adhesive strips are frequently applied across the incision line to provide temporary support as the wound continues to gain strength.