Wound Closure and Suture Technique

Wound Closure and Suture Technique

Gary D. Monheit, M.D.
Associate Professor
Department of Dermatology
University of Alabama at Birmingham
Birmingham, Alabama

The purpose of suturing is wound closure. Ideally, suturing should approximate the wound edges so that the tissues can reestablish closure with a final scar that is functional and aesthetic. The method and techniques of suturing as well as materials used are determinants in the final outcome. The surgeon must also have a full understanding of wound healing, tensile strength, and wound closure to perform skin approximation. Ideally, the wound should be approximated with little tension and the skin edges handled gently. It is the fine attention the surgeon gives to handling skin edges and the techniques of approximation that create the optimal aesthetic scar line. This chapter will review the techniques and materials available for suturing wound closure.

The history of dermatologic surgery begins in the ancient world where evidence of surgical wound closure is found in the Edwin-Smith Papyrus relating methods of suturing and dressings. The document relates a deep facial wound which was closed with silk sutures and covered with linen dressings and ointments.1

Wound closure was also noted in ancient Indian sanskrit texts describing suture material made of animal sinews, bark, leather straps and even ant pincers.

The importance of cosmesis in wound closure was noted by the Greeks and Romans with the first description of layered closures, local flaps and pedicles. Galen referred to the usage of catgut and silk suture material for closures and as vessel ligature. The principles of antiseptics by Lister later enabled sterile wound closures to progress to the modern era for fine cosmetic dermatologic surgery.

The Materials

Needle and Suture

All surgical needles have three basic components; the point, the body, and the swage.2 Most all sutures used in dermatologic surgery are directly attached to a surgical needle rather than threaded through a hole. The swage is the tail of the needle connecting the suture. The suture is inserted into the hollow end of the needle and is mechanically crimped to hold the suture securely in place. The swage is the broadest point of the suture. The tip of the needle is the fine delicate point which pierces the skin. The remaining portion where the needle is grasped with instruments is the body. The needle body can be round, triangular, or oval and may have ribs for grasping. Most needle bodies have an arc of either 135 (3/8 circle), or 180 degrees (1/2 circle).3 Either of these configurations can be helpful for various suture techniques. For deep closure in which both fascia and subcutaneous tissue must be grasped to close dead space, the 180 degree needle is helpful. It is also helpful when suturing in cavities in which the arc of closure needs to be smaller to bring deeper tissue together. The 3/8 circle, though, seems easier to handle for basic skin closure on an open surface. The needle point is a triangle with three cutting surfaces. A conventional cutting needle has the third cutting edge of the triangle on the inside surface of the needle arc. This places the apex of the triangle facing the wound. The reverse cutting needle has the triangular tip pointing away from the wound edge or on the outside of the arc. This creates less cutting with tension on the suture line.4 For fine plastic closures, reverse cutting is advantageous. Needles also differ as to material and needle sharpness, and are coated by the major companies as for usage and durability. F.S. (for-skin) is least expensive and for non-cosmetic skin closures. The P, PS and PC refer to plastic, plastic skin, and precision cosmetic needles which are made of higher quality steel and honed to a sharper point. The dermatologic surgeon can choose which of these materials best suits his needs in areas of wound closure. For example, a PS or PC needle should be used for fine facial skin closure while an FS needle is sufficient for suture closure on a covered area of the body.5

Suture Material

Suture material is generally divided into two types, absorbable and non-absorbable. Each has a distinctive role when used properly for wound closure techniques. Ideally, wounds are closed under minimal or no tension so that skin edges can be directly approximated and sutures placed for five to seven days. Absorbable suture will be digested by enzymes or hydrolysis and, thus, do not need to be removed from the closed wound. These are placed normally in fascia, subcutaneous tissue, and deep dermis to close defects and take skin tension off the skin surface edges. After skin tension is fully removed, permanent sutures are used to approximate the skin surface for precise coaptation of the epidermis. Permanent surface skin sutures should be removed within five days to reduce the incidence of tunneling or skin tracts which occur as the epidermis grows around the suture tracts. Prompt removal of these permanent sutures, though, can only be done if the tension is alleviated by buried absorbable suture which will maintain the strength of the wound edge until collagen synthesis has been completed and the scar line is stable.6 It is, thus, the surgeon's knowledge of suture material and wound healing to give the best combinations for wound closures in various parts of the body.

Surgical Instruments for Wound Closure

The standard instruments used for wound closure include a needle holder or driver, tissue forceps, skin hooks, needle forceps, and suture scissors. These tools vary in size, material and shape depending on their usage for wound closure. Matching the appropriate instruments with the needle size and suture material as well as the defect to be closed is essential for good surgical work. For example, a 6 mm. eyelid defect should be closed with 6-0 prolene suture, a delicate Castroviejo needle holder, and .5 Adson needle holder. The use of these delicate instruments with larger suture and needles may bend instruments and damage them. Thus, the surgical instrument must be correlated to needle and suture size.

The standard needle holder has a ratchet locking mechanism that stabilizes the needle securely in its jaws. The needle holder should be locked on the first ratchet and not beyond as this indents the needle and damages the holder. The needle should be grabbed 3/4 distance along its body for accurate stabilizing. For most facial skin closures the delicate ratchet locking Webster needle holder made of stainless steel with a carbon bite aids the surgeon in accurate suture placement. Larger needle holders conventionally used in general surgery are awkward, cumbersome, and inhibit good cosmetic work. Tissue forceps should delicately grasp skin edges with little or no trauma to the wound surface. Flat forceps compress and squash skin edges creating ragged scar lines. The Adson tissue forcep creates less trauma but still pinches the skin edge with pinpoint trauma. The most delicate of tissue forceps is the Brown-Adson with its fine tooth-like projections which can delicately move the skin edges with little compression or tissue necrosis.

The most delicate instrument, though, is the skin hook which can both pull and push tissue with little or no trauma. One needs dexterity and experience to use this instrument carefully and the danger of skin puncture to the surgeon is present if one is not careful. It behooves the good dermatologic surgeon to learn the techniques to use this instrument properly for good cosmetic closure.

Suture scissors can either be of the iris type or hooked variety. What is necessary is that the scissors should be able to cut the suture cleanly near its tip. This should work as effectively for buried suture in subcutaneous tissue and skin sutures. Undermining tissue scissors should not be used to cut suture. Monofilament suture and the synthetic nylons will dull tissue scissors and make them ineffective instruments for undermining. thus, the basic instruments on a typical repair tray should include:

Suture Technique

Proper use of sutures to close surgical wounds takes planning prior to the surgical session to elevate the levels of closure. What will the depth of the wound and the resultant tension on the skin edge do to the final scar line? A simple closure is the use of direct interrupted non-absorbable skin sutures to close the wound with interrupted sutures. A layered closure entails buried absorbable sutures and interrupted permanent skin sutures. A complex closure involves the essentials of layered closures along with methods to reduce skin tension such as undermining and tissue transfer.13 The surgeon must evaluate his excision and then his defect as to the anatomic site and the nature of skin tensions for the appropriate closure. Each of these will be reviewed in the general concepts of wound closure. Interrupted suture closure is the simplest and easiest method to close uncomplicated wound defects. To use interrupted suture as the primary mechanism of closure, the defect must be:

An interrupted suture is placed through opposite wound edges, full thickness through the skin, to bring the wound edges together. The technique is accomplished as follows:

The advantages of interrupted sutures for simple closures is the ease and simplicity of the procedure. The risks are small and it provides stability for the wound edges during healing. Disadvantages include inversion of the suture line if the suture is placed too superficial. That is, if the tension pull across the suture line is too superficial, it will pull the scar line downward creating a trough. The other disadvantage is the railroad tracking or scar tunnels left by the suture if kept in for the five to seven days necessary for wound healing.

Vertical Mattress Sutures

The vertical mattress suture is used to accentuate eversion when there is significant skin tension and to close dead space in deeper tissue defects. Vertical mattress sutures can be placed in conjunction with interrupted sutures to ensure significant wound closure tension and evert the skin edges. Between these, interrupted sutures are placed. The vertical mattress suture is begun 0.5 to 1 cm. from the wound edge with the needle pointed vertically to the depth of the wound, then under the wound and back out along opposing sides equidistant from the wound edge. The needle is then reversed, the skin is penetrated again on the same side but closer to the wound edge and at this point, passes more superficially through dermis to the opposite side exiting the same distance from the wound margin, 1 to 3 mm. from the wound edge. The sutures are then pulled together bringing the wound edges together and at the same time, obliterating dead space and everting the wound edge. Care must be taken to place the right amount of tension on the suture edge so as to close the defect without crushing tissue and skin caught within the suture. Excessive pressure at the depth of the wound can cause ischemic necrosis and strangulation so, thus, it is important to minimize wound tension prior to tieing the knots. This is a strangulating suture with significant tension on the scar line. Thus, the vertical mattress suture is rarely used on the face because it does produce scarring. Other methods of reducing tension such as buried suture with fine approximating sutures are reserved for facial closures.

Horizontal Mattress Suture

Horizontal mattress sutures are used for minimizing wound tension, closing dead space, and further exaggerating wound edge eversion. Areas with significant wound tension such as the back, the chest, and the scalp may need a horizontal mattress suture to ensure that tension is reduced during healing. On wound closure, one or two horizontal mattress sutures may be used in conjunction with interrupted sutures to approximate a wound edge properly. With a horizontal mattress suture, the needle penetrates the skin 1/2 to 1 cm. from the wound edge and passes vertically to the depth of the defect across the depth of the defect then back out along the opposing side the same distance from the wound edge. It re-enters at the same distance from the wound edge and passes vertically to the depth of the wound and back out along an equidistant space on the opposing side. The double square knot is then used to tie this off, being careful that tension will approximate the skin edges and is not too great. This is a strangulating suture as the vertical mattress suture, and can crush the tissue with tension. A bolster may be used with the horizontal suture.

Layered Closure

A layered closure is the use of buried absorbable sutures in fascia, subcutaneous tissue, deep dermis, combined with the use of buried absorbable suture in deeper skin and tissue removes the tension from the skin edge and provides stable reduction of closure tension during healing. To perform this correctly, the wound must be prepared. This includes undermining the skin a minimum of 2 mm. and, at times, up to 1 cm. beyond the wound edge to reduce skin tension and for the accurate placement of the buried absorbable suture. Meticulous hemostasis has been accomplished prior to suture placement. The type of buried suture used depends on the thickness of the defect, the tension on the wound, and the amount of dead space.

The buried subcutaneous suture or the dermal subdermal stitch is begun first to the deep side of one of the undermined edges of the defect. This is accomplished by lifting the wound edge with a skin hook and advancing the needle tip 1 or 2 mm. from the wound edge on the undersurface of the skin. This allows the suture pathway to proceed upward through subcutaneous tissue entering into mid dermis. It will then pass through the wound margin at mid dermis and reenter the opposite wound side through mid dermis proceeding in an arc downward to the opposing subcutaneous tissue and exiting 2 or 3 mm. from the wound edge. The suture lines are then tied with the knot pulled along the long axis of the defect. This allows the knot to slide to the base of the defect in the subcutaneous tissue, burying the knot. Pulling the suture line perpendicular to the scar line will trap the suture upward creating an inadequate closure and a knot placed too high. Multiple buried subcutaneous sutures are placed along the defect reducing tension along the skin edge at critical points. This will then allow the placement of single interrupted sutures with no tension on the skin edge, minimizing scarring. It also stabilizes wound closure so that the interrupted suture may be removed in under seven days, producing a better cosmetic result. It also lessens the risk of surgical dehiscence when the interrupted sutures are removed. The buried absorbable suture will maintain closure tension during healing. Layered closure using buried sutures is a useful technique for skin closures and this author feels it can be used in most areas of the skin surface. Dangers with buried sutures include foreign body reaction, strangulation of deep tissue with necrosis, local infection, and prolonged inflammation.14

Chromic suture has the highest potential for inflammation and possibilities of secondary infection. This becomes increased if the suture is placed high on the surface or the knot is wide enough to strangulate deep tissue causing necrosis. If the knot is placed superficial with a significant amount of inflammation, a persistent nodule can occur which may last for months. It may cause suppuration with superficial necrosis and the suture extravasating or spitting through the surface.15 Rarely, it can induce scar tissue that will make a persistent nodule. Techniques to prevent these complications include:

After buried suture has been placed correctly, tension has been eliminated from the skin margin. At this point, the skin surface can be draped together and approximated with interrupted sutures. These can be removed in four to six days because there is no tension on the skin margin. It will, thus, be possible to avoid stitch marks along the scar line by removing the sutures early.

Complex Closures

Complex closures usually involve more extensive undermining and local skin movement. Both of these preliminary closure techniques involve a combination of suture techniques in the deeper dermis as well as on the skin surface. Each of these closure techniques will be reviewed in context to the clinical situation where it is most likely to be used. The basis of these techniques depends upon reducing skin tension with buried suture below the skin surface. This must be performed with fascial sutures, buried subcutaneous sutures, and interrupted dermal sutures to take the tension off the skin edge. It is only then that the variety of running suture, running locking suture, tip stitch, and running subcuticular sutures can be used for skin margin approximation.

Tip Stitch

The tip stitch is a modification of the horizontal mattress suture in which half the suture is buried. It is used to secure and close acute angles of closure with tips of skin that would be damaged by interrupted suture. In this way, the suture travels through the dermis of the tip and advances the tip with interrupted sutures on either sides. It, thus, is used to secure the tip of skin flaps without compressing the epidermal tissue and avoiding ischemic necrosis. Mechanically, the needle is passed through the skin on one side of the V, exiting mid dermis and penetrating the tip mid dermis and back out along the opposite side mid dermis. It then will go through the opposite side of the V at a mid dermal level and exit through the skin. As the suture is pulled, the tip will advance into the V with enough pressure for good closure. It then is tied with a double square knot. The tip stitch is useful in the closure of M-Plasties, angles along transposition flaps, geometric broken line closures, and Z-Plasties.16

Running Suture

The running suture can be used to close skin edges in wounds in which tension has been reduced fully. It is an approximating suture which can simply and easily close a long scar line. Using permanent suture, it is useful on body surface areas such as the retroauricular sulcus, upper eyelids, and supraclavicular neck where skin grafts are harvested. It can also be used for closures of body skin in which tension has been reduced with interrupted subcutaneous sutures. In facial closures, a running suture of 6-0 mild chromatized gut is used in conjunction with buried subcutaneous sutures to reduce tension. The mild chromatized gut suture, when placed under steristrips, will be absorbed in four to six days. When the steristrips are removed, the suture is absorbed. This will prevent suture marks or cross hatch scars and alleviates the need for suture removal.

The running suture is initiated by placing a simple interrupted suture at one end of the wound that is tied but not cut. Simple suture passes are then placed down the length of the wound as a "baseball suture" until the end of the suture line is reached. At this point, it is simply tied off with a simple knot created by the last loop of suture. Running suture shares tension along the closure line creating an even scar line. It is an easy and rapid method of closing wounds and when used correctly, it will create a cosmetically superior scar line. Performed incorrectly, though, it can cause thicker tissue to bunch and pucker and if placed too deeply, may create uneven edges. It can strangulate the epidermal edge if pulled too tight and create an uneven, cross-hatched scar.

Running Locked Suture

Locking the running suture as it is closed is a modification that will counteract some degree of tension on the skin edge. It can be performed as a locked suture for each pass or individualizing locked when needed for areas of tension along the scar line. Additionally, it may help prevent inversion of the wound edge which can account for an uneven thickness in skin types. This suture technique is best performed with an assistant who can grab the needle with each pass and place it back in the surgeon's needle holder. It, thus, can be used efficiently for both running and running locked suture lines. The major disadvantage of this technique is that it may strangulate the skin edges creating excessive scarring. This is overcome by taking small bites and keeping tension on the suture line to what is minimally needed.

Running Subcuticular Suture

The running subcuticular suture uses a permanent monofilament suture placed as a horizontal running intradermal suture. The successful use of this suture is dependent upon reduction of tension below the skin surface with buried subcutaneous sutures. With skin tension removed, the two skin edges then can be draped together and approximated with a running subcuticular suture. The running subcuticular suture is begun by placing the needle through one wound edge and enters into the defect. The opposite edge is held firmly with a skin hook as the needle is passed in a horizontal pattern through the mid dermis. It exits with a 1/2 cm. pass and then is brought in approximation to the opposite wound side and enters the mid dermis. This is repeated on alternate sides of the wound as the suture is advanced down the wound edge. It is then terminated at the skin surface and then the surgeon can pull the monofilament back and forth to adjust the tension correctly. Because the suture is entirely below the skin surface, permanent monofilament suture may be left in place for two or even three weeks without risk of skin marks.17 At that time, the suture can be removed promptly by pulling out along the long axis of the scar line. Braided or silk suture should not be used as a subcuticular stitch as this cannot be removed after two weeks. The subcuticular suture is used primarily to enhance the cosmetic results with defects in which tension has been fully reduced and the skin edges are of relatively equal thickness.

Combined Closure Techniques

A preferential approach to facial defects in which maximal cosmetic results are necessary is to use as a complex closure the use of both buried absorbable suture and permanent suture. Closure is performed in a layered fashion with buried dissolvable suture in fascial layers of subcutaneous tissue and buried dissolvable suture place in the skin. Chromic suture or vicryl suture of 4-0 or 5-0 can be used depending on the thickness of the skin and the location of the excision. Tension should be fully removed from the skin with buried sutures so that the permanent skin sutures placed for final approximation will not have any tension or pull. This will reduce the incidence of suture lines and cross hatches or stretching on the scar line. For further approximation of an elliptical closure, 5-0 prolene suture may be used where tension still exists on the skin edge. Dog-ears or skin redundancy at the tips should be repaired at the time of closure and geometric points closed with appropriate tip stitches. A final skin layer of 6-0 mild dissolvable chromic suture is placed in the facial skin to further coapt the skin edges together and level the sides equally. A running baseball suture can be placed with no tension and ties at the ends. This mild chromic suture or fast dissolving suture is occluded with steristrips. Since this suture dissolves within five days, there will be no epithelial channels on the skin to create cross hatches or suture marks when the dressing is removed in seven to ten days. Being able to leave the wound dressing for this longer period of time will enhance the stability of the scar and lessen the incidence of dehiscence. Anti-tension tape stripping is important for both occlusion and to take tension off skin edges. These strips which are covered with narrow 1/2 inch flesh colored paper tape will create a stable wound bandage that may be left in place for the entire week. This will also cover the wound for protection and for cosmetic reasons during healing.

Techniques of suture and wound closure, thus, are essential for good dermatologic surgery. Though many of the techniques appear basic, a thorough understanding of these techniques is essential for the dermatologic surgeon to close wounds correctly.

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