Principles of Suturing
Once the surgical procedure is completed and the wound properly irrigated and debrided, the surgeon must return the flap to its original position or, if necessary, arrange it in a new position the flap should be held in place with sutures. Sutures perform multiple functions. The most . obvious and important function that sutures perform is to coapt wound margins that is, to hold the flap in position and approximate the two wound edges. The sharper the incision and the less trauma inflicted on the wound margin, the more probable is healing by primary intention. If the space between the two wound edges is minimal, wound healing will be rapid and complete. If tears or excessive trauma to the wound edges occur, wound healing will be by secondary intention.
Sutures also aid in hemostasis. If the underlying tissue is bleeding, the surface mucosa or skin should not be closed, because the bleeding in the underlying tissues may continue and result in the formation of a hematoma. Surface sutures aid in hemostasis but only as a tamponade in a generally oozing area, such as, a tooth socket. Overlying tissue should never be sutured tightly in an attempt to gain hemostasis in a bleeding tooth socket.
Sutures help hold a soft tissue flap over bone. This is an extremely important function, because bone that is not covered with soft tissue becomes nonvital and requires an excessively long time to heal. When mucoperiosteal flaps are reflected from alveolar bone it is important that the extent of the bone be recovered with the soft tissue flaps. Unless appropriate suture techniques are used, the flap ‘may retract away from the bone, which exposes it and results in delayed healing.
Sutures may aid in maintaining a blood clot in the alveolar socket. A special stitch, such as a figure-eight stitch, can provide a barrier to clot displacement (Fig. 8-15). However, it should be emphasized that suturing across an open wound socket plays a minor role in maintaining the blood clot in the tooth socket.
The armamentarium includes a needle holder, a suture needle, and suture material. The needle holder of choice is 15 cm in length and has a locking handle. It is held with the thumb and ring finger through the rings and with the index finger along the length of the needle holder to provide stability and control (Fig. 8-16).
The suture needle usually used in the mouth is a small three eighths to one-half circle with a reverse cutting edge. The cutting edge helps the needle pass through the relatively tough mucoperiosteal flap. Needle sizes and’ shapes-have been assigned numbers. The most common needle shapes used for oral surgery are the FS-2 and X-I (Fig. 8-17).
Sutures are made of a wide variety of materials and come in several sizes each designed for a particular purpose. The two basic types of suture material are (1) resorbable (i.e. the body is capable of easily breaking the material down) and (2) nonresorbable. In general, resorbable sutures do not require removal, whereas nonresorbable sutures do.
Three types of resorbable sutures are commonly used for oral and maxillofacial surgery (1) gut, (2) polyglycolic acid, and (3) polyglactin. Gut is fabricated from the submucosa of sheep intestines or the serosa of beef intestines. Plain gut is susceptible to rapid digestions by proteolytic enzymes produced by inflammatory cells. Treating the gut suture with basic chromium salts produces chromic catgut, which is more resistant to proteolytic enzymes. Plain gut sutures retain ‘their strength for
approximately 5 days, whereas chromic gut sutures maintain their strength for 7 to 9 days. Polyglycolic acid and polyglactin sutures do not enzymatically break down. Rather they undergo slow hydrolysis, eventually being resorbed by macrophages. Polyglycolic and polyglactin sutures have the advantage of being less stiff than gut sutures and are morelikely to remain tied. However, they may last too long and are more costly than gut sutures.
Resorbable sutures are highly reactive compared with nonresorbable sutures; that is, resorbable sutures evoke an intensive inflammatory reaction that may impede wound healing, occasionally to a clinically significant extent. This is the reason that neither plain nor chromic gut is used for suturing the surface of a skin wound.
The most commonly used nonresorbable sutures in oral and maxillofacial surgery are silk, nylon, polyester, and polypropylene. Nonresorbable sutures are either monofilament or multifilament. The multiflament form increases the strength of the suture, but also increases suture abrasiveness and is more likely to allow.bacteria to “wick” into the wound. Silk and polyester sutures are
available only in multifilament form. Polypropylene is produced only as a monofilament, whereas nylon comes as both a monofilament and a multifilament form.
All nonresorbable sutures have some reactivity. Of the commonly used nonresorbable sutures, silk revokes the most intensive inflammatory reaction and nylon is the least reactive. In situations in which it is important to minimize wound inflammation, such as any facial laceration,nylon is usually the cutaneous suture of choice.
Sutures are available in various sizes that range from the largest diameter, 7, down to the smallest extremely fine suture size, 11-0. The increasing number of O’s correlates with decreasing suture diameter and strength. For example, size 1-0 suture is larger in diameter than size 2-0, size 3-0 is larger than 7-0, etc. Because suture material is foreign to the human body, the smallest diameter of suture sufficient to keeping a wound closed properly should be used. Generally the size of the suture is chosen to correlate with the tensile strength of the tissue being sutured. Most oral and maxillofacial surgeons use 3-0 or 4-0 suture.
The technique used for suturing is deceptively difficult. The use of the needle holder and the technique that is necessary to pass the curved needle through the tissue arc difficult to learn, The following discussion presents the technique used in suturing practice is necessary before suturing can be performed with skill and finesse.
When the envelope flap is repositioned into its correct location, it is held in place with sutures that arc placed through the papillae only. Sutures are not placed across the empty tooth socket, because ‘the edges of the wound would not be supported over sound bone (Fig. 8-18). When reapprox.mating the flap, the suture is passed first through the mobile (usually facial) tissue; the needle is
rcgrasped with the needle holder and passed through the attached tissue of the lingual papilla. If the two margins of the wound are close together, the experienced surgeon may be able to insert the needle through both ,sides of the wound in a single pass. However, it is best to use two passes in most situations (Fig. 8-1″9).
When passing the needle through the tissue, the needle should enter the surface of the mucosa at a right .angle, to make the smallest possible hole in the mucosal flap (Fig. 8-20). If the needle passes through the tissue obliquely, the suture will tear through the surface layers of the flap when the suture knot is tied, which results in greater injury to the soft tissue.
When passing the needle through the flap, the surgeon must ensure that an adequate bite of tissue is taken, to prevent the suture from pulling through the soft tissue flap. Because .the flap that is being sutured is a mucoperiosteal flap and should not be tied tightly, a relatively small amount of tissue is necessary. The minimal amount of tissue between the suture and the edge of the flap should be 3 mm. Once the sutures are passed through both the mobile flap and the immobile lingual tissue, they are tied with an instrument tie (Fig. 8-21).
The surgeon must remember that the purpose of the . stitch is merely to reapproximate the tissue, and therefore the suture should not be tied too tightly. Sutures that are too tight cause ischemia of the flap margin and result in tissue necrosis, with tearing of the suture through the tissue. Thus sutures that are too tightly tied result in wound dehiscence more frequently than sutures that are loosely tied. As a clinical guideline, there should be no blanching or obvious ischemia of the wound edges. If this occurs the suture should be removed and replaced. The knot should be positioned so that it does not fall over the incision line, because this causes additional pressure on the incision. Therefore the knot should be positioned to the side of the incision.
If a three-cornered flap is used, the vertical end of the incision must be closed separately. Two sutures usually are required to close the vertical end properly. Before the sutures are inserted, the Woodson periosteal elevator ‘should be used to elevate slightly the nonflap side of the incision, freeing the margin to facilitate passage of the ‘ needle through the tissue (Fig. 8-22). The first suture is placed across the papilla, where the vertical release incision was made. This is a known, easily identifiable landmark
that is most important when repositioning a three cornered flap. The remainder of the envelope portion of he incision is then closed, after which the vertical component is closed. The slight reflection of the nonflap side of the incision greatly eases the placing of sutures.
The sutures are left in place for approximately 5 to 7 days. After this time they play no useful role and, in fact, probably increase, the contamination of the underlying submucosa When sutures are removed, the surface debris that has collected on them should be cleaned off with a cottontipped applicator stick soaked in peroxide, chlorhexidine, iodophor, or other antiseptic solution. The suture is cut with sharp, pointed suture scissors and removed by pulling it toward the incision line (not away from the suture line).
Sutures may be configured in several different ways.The simple interrupted suture is the one most commonly used in the oral cavity. This suture simply goes through one side of the wound, comes up through the other side of the wound, and is tied in a knot at the top. These sutures can be placed relatively quickly, and the’ tension, on each suture can be adjusted individually. If one suture is lost the remaining sutures stay in position.
A suture technique that is useful for suturing two papillae with a single stitch is the horizontal mattress suture (Fig. 8-23). A slight variation of that suture is the figure eight suture, which holds the two papilla in position and puts a cross over the top of the socket so that may help hold the blood clot in position (see Fig. 8-15).
If the incision is long, continuous sutures can be used efficiently. When using this technique, a knot does not have to be made for each stitch, which makes it quicker to suture a long-span incision. The continuous simple suture, can be either locking or nonlocking (Fig. 8-24). The horizontal mattress suture also ‘can be used in a running fashion. A disadvantage of the continuous suture is that if one suture pulls through, the entire suture line becomes loose.