++
Proper size suture material can be summarized as the smallest suture needed to approximate the edges of a wound. This will reduce tissue damage caused by the suture, and the resulting scar will be minimized. The tensile strength of the suture should never exceed the tensile strength of the tissue, or it can pull through and damage the tissue. The sutures should be at least as strong as the normal tissue through which they are being placed.
++
The size of the suture material is related to the diameter of the suture. As the number of 0s in the suture size increases, the diameter of the strand decreases. For example, size 5-0, or 00000, is smaller in diameter than size 4-0, or 0000. The smaller the size, the less tensile strength the suture will have.
++
Suture description entails numerous characteristics. Sutures can be classified into two major groups based upon the number of strands of which they are composed. Monofilament sutures are made of a single strand of material. They encounter less resistance passing through tissue and resist harboring organisms that may cause suture-line infections. Multifilament sutures consist of several filaments, or strands, that are twisted or braided together. This affords greater tensile strength, pliability, and flexibility. Unfortunately, bacteria can migrate between the filaments and into the wound.
++
Another classification is based on the ability of the body to break down and absorb the suture material. Absorbable sutures are digested by body enzymes or hydrolyzed in body tissue. Nonabsorbable sutures are not digested by body enzymes or hydrolyzed.
++
Absorbable suture can be made of natural or synthetic material. Natural absorbable suture is classified as surgical gut (plain or chromic). Plain surgical gut is composed of collagen from bovine or sheep intestine. It is rapidly absorbed, maintaining its tensile strength for only 7 to 10 days, and is completely absorbed within 70 days. Chromic gut is treated with a chromium salt solution to resist body enzymes. It retains its tensile strength for 10 to 14 days and is absorbed over 90 days.
++
Synthetic absorbable sutures include polyglactin 910 (Vicryl, Ethicon) and polyglycolic acid (Dexon). They were developed because of the tissue reaction, suture antigenicity, and unpredictable rates of absorption of natural absorbable sutures. These sutures are braided synthetic materials that retain 50% of their initial strength at 4 weeks. The synthetic absorbable sutures retain their tensile strength long enough to ensure the security of the subcutaneous layers after the removal of percutaneous sutures.
++
Nonabsorbable sutures are made of silk, nylon, polypropylene, cotton, linen, or metal. They can be monofilament or multifilament in construction. Nylon is the most commonly used suture in the Emergency Department. It is used to approximate lacerations at the skin surface. Silk may occasionally be used in the mouth. It causes significant tissue reactions that result in inflammation and granuloma formation as the body “fights off” this natural fiber. The other types of nonabsorbable sutures are generally not utilized in the Emergency Department.
++
Several factors must be considered in choosing suture material. Choose sutures that match the healing properties of the tissues. Approximate slow-healing tissues (e.g., fascia and tendons) with nonabsorbable sutures or a long-lasting absorbable suture. Foreign bodies in potentially contaminated tissues may result in an infection. Multifilament sutures can act as a foreign body and may convert a contaminated wound into an infected one. Multifilament sutures should generally be avoided. Use monofilament sutures or absorbable sutures that resist harboring infection. Use the smallest inert monofilament suture materials (such as nylon or polypropylene), avoid using skin sutures alone (use subcuticular closure whenever possible), and use sterile skin closure strips for apposition when possible. Use the smallest possible size of the chosen suture type that is capable of closing the wound to help minimize scarring.
++
Needles are generally of two types, tapered and cutting (Figure 92-6). Cutting needles have sharp ends and sharp edges that act as a cutting instrument (Figure 92-6A). The cutting needle is commonly used for tougher tissues such as subcutaneous, intradermal, and cutaneous (skin) closure. In addition to the two cutting edges, conventional cutting needles have a third cutting edge on the inside concave curvature of the needle. This needle type may be prone to “cutout” of tissue because the inside cutting edge cuts toward the edges of the incision or wound.
++
++
Reverse cutting needles are as sharp as the conventional cutting needle except that the third cutting edge is located on the outer convex curvature of the needle (Figure 92-6B). Reverse cutting needles have more strength than similar-sized conventional cutting needles. The danger of tissue “cutout” is greatly reduced. The hole left by the needle leaves a wide wall of tissue against which the suture is to be tied.
++
Taper point needles have a pointed end (Figure 92-6C). The rest of the needle is a smooth, rounded tube with no cutting edges. This type of needle is commonly used in surgery to close tissues with minimal trauma. It is used for all tissues except skin.
++
Two other types of needles are often available but not used in the Emergency Department. The blunt point needle has a smooth tip and tapered body (Figure 92-6D). It is used for suturing friable tissue and blunt dissection. The taper cut needle has a cutting tip and a tapered body (Figure 92-6E). It is a combination of the tapered point and cutting needle. It is used to place sutures through tough tissues. Numerous other needles are available, as are modifications of the five basic needle types. These needles are used by Surgeons for specialized tissues.
++
Always keep some general principles in mind when suturing. Needles should be pulled through tissue using a needle driver and never a hemostat. A hemostat or other clamp can damage the needle. Avoid injury to yourself and others. Keep all open needles in a place so that they will not injure you or your assistant. Account for and discard all suture needles in a “sharps” container. Following these two steps will dramatically decrease the chance for a needle-stick injury.
+++
Needle Drivers and Handling Sutures
++
Always use a needle driver when suturing. The use of a hemostat or other type of “clamp” can damage the needle and cause it to bend or break in the tissue. Needle drivers are generally made of steel with a jaw designed to hold the needle securely without damaging it. They come in numerous sizes and shapes. Choose a needle driver that is an appropriate size for the needle that is to be grasped. A 4.5 to 6 in. long needle driver is appropriate for Emergency Department use. Grasp and remove a clean needle from its package with your hands, forceps, or a needle driver. Securely grasp the proximal one-third to one-half of the needle with the needle driver (Figure 92-7A). Do not grasp the distal one-third of the needle. This can damage its cutting surfaces. Always use the tips of the needle driver to grasp the needle (Figure 92-7B). Grasping a needle with the base of the jaws may damage the needle.
++
++
Use the needle driver when pushing the needle through the tissue to place a suture (Figure 92-7C). Apply the force in a direction following the curve of the needle. Do not twist or force the needle to push the point through the tissue and out the other side. Use a larger needle if the first one is too short or too small. Do not use a needle that has become dull and difficult to pass through the tissue. Obtain a new needle and continue the procedure. Grasp the distal tip of the needle with a needle driver when it emerges from the tissues (Figure 92-7D). Always grasp the needle proximal to its distal third to prevent damage to the cutting edges.
++
Always use caution when handing a needle driver armed with a needle to another person. Grasp the needle driver between the thumb, index, and middle fingers (Figure 92-7E). Hand the base of the needle driver to another person. Do not blindly pass the needle driver. Do not pass the needle driver over a third party without their knowledge of the transfer. Never grasp the distal end of an armed needle driver.
++
Typical needle drivers contained within most disposable, commercially available laceration repair trays are not ideal. The suture often snags on the jaws or hinge when performing an instrument tie. Some needle drivers are designed to be snag-free (Figure 92-8). Two of these, the Centurion SnagFree (Centurion Healthcare Products, Howell, MI) and the SutureCut (SutureCut LLC, Lexington, KY) needle drivers, are available both as individual disposable instruments and in disposable laceration repair trays.
++
++
Suturing lacerations can take a significant amount of time. Much of this time is spent tying knots or switching between instruments (i.e., the needle driver and scissors). Two needle drivers are designed to also cut suture. This decreases the total time required to repair a laceration as well as avoiding the constant switching between instruments. The SutureCut (SutureCut LLC, Lexington, KY) and the Olsen-Hagar (Henry Schein Inc., Port Washington, NY) needle drivers cut the suture in their specially designed joint located at the base of the jaws.
++
We are all not fortunate to have suture-cutting needle drivers in our laceration repair trays. A needle driver and scissors can be simultaneously held in the same hand to improve efficiency (Figure 92-9). While awkward at first, this technique is easy to learn. Grasp a scissors with the tip pointing ulnarly (Figure 92-9A). Insert your middle finger through the adjacent ring on the handle. Grasp a needle driver in the same hand with the tip pointing radially (Figure 92-9A). Insert your thumb and ring finger through the rings on the handle of the needle driver. Grasp a suture needle with the needle driver. Place a stitch and tie it. Remove your thumb from the ring of the needle driver and place it in the open ring of the scissors. Use the thumb to open and close the scissors. Cut off the excess suture (Figure 92-9B). Place your thumb back into the ring of the needle driver and place the next stitch. Repeat this process until the laceration is closed.
++