Sutures are the strongest of all the closure devices and allow the most accurate approximation of the wound edges, regardless of their shape or configuration. However, sutures are the most time-consuming and operator dependent of all wound closure methods and have the risk of inadvertent needle-stick injury. Using forceps to handle the needle during suturing can reduce this risk. A needle-catcher device is reported to be useful in reducing needle-stick injury during skin suturing.7,8,9
Sutures may be classified as absorbable and nonabsorbable. Nonabsorbable sutures retain their tensile strength for at least 60 days. They are most often used to close the outermost layer of the skin (where they can be removed) or for repair of tendons (where prolonged strength is necessary due to very high tension). In general, nonabsorbable sutures are avoided in deep vascularized tissues where their presence stimulates a foreign body response with fibroblastic proliferation. Nonabsorbable sutures are differentiated by their origin and structure (Table 41-2). Due to their strength, handling, and relatively low tissue reactivity, synthetic monofilament sutures (such as nylon or polypropylene) are preferred. Polybutester sutures have the ability to elongate in response to external forces and possess elasticity to return to the original size once the load is removed. This property may be useful in wounds where swelling is anticipated. Less distensible sutures, such as nylon or polypropylene, cannot expand, and instead may lacerate the wound edges as the tissue swells.
TABLE 41-2Nonabsorbable Suture Characteristics ||Download (.pdf) TABLE 41-2 Nonabsorbable Suture Characteristics
|Suture ||Structure ||Raw Material ||Tensile Strength Retention Profile ||Tissue Reactivity ||Common ED Uses |
|Silk ||Braided ||Organic protein fibroin ||Degradation of fiber results in loss of strength over many months ||Significant inflammatory reaction ||Intraoral mucosal surfaces for comfort |
|Nylon (Ethilon®, Dermalon®) ||Braided and monofilament ||Polyamide polymer ||Hydrolysis results in 20% loss in strength per year ||Minimal ||Soft tissue and skin reapproximation |
|Polypropylene (Prolene®, Surgipro®) ||Monofilament ||Polypropylene polymer ||Indefinite ||Least ||Soft tissue and skin reapproximation |
|Polyester (Mersilene®, Ti·Cron®) ||Braided and monofilament ||Polyethylene terephthalate polymer ||Indefinite ||Minimal ||Tendon repair using undyed (white) color |
|Polybutester (Novafil®) ||Monofilament ||Copolymer of butylene terephthalate and polytetramethylene ether glycol ||Indefinite ||Minimal ||Soft tissue approximation |
Absorbable sutures lose most of their tensile strength in less than 60 days. As a result, they are well suited for closure of deep structures such as the dermis and fascia (Table 41-3). Poliglecaprone 25 has handling characteristics that are similar to nonabsorbable sutures (such as nylon) and is particularly useful for intracuticular or subcuticular closure. Due to its rapid absorption, poliglecaprone 25 should probably be limited to relatively low-tension wounds. With high-tension wounds, a suture with more sustained tensile strength is preferred. Absorbable sutures that incorporate the antibacterial agent triclosan are also available and may be especially indicated in contaminated wounds.10,11 Rapidly absorbing sutures can also be used to close the superficial skin layers, especially when avoidance of suture removal is desirable.12,13,14,15
TABLE 41-3Absorbable Sutures ||Download (.pdf) TABLE 41-3 Absorbable Sutures
|Suture ||Structure ||Raw Material ||Tensile Strength Retention Profile ||Absorption Rate ||Tissue Reactivity ||Common ED Uses |
|Surgical gut ||Monofilament ||Collagen derived from beef serosa or sheep submucosa ||7–10 d ||Absorbed by proteolytic processes in 70 d ||Moderate reactivity ||Intraoral wounds |
|Chromic gut ||Monofilament with chromic salt coating ||Collagen derived from beef serosa or sheep submucosa ||21–28 d ||Absorbed by proteolytic processes in 90 d ||Moderate reactivity ||Subcutaneous approximation and intraoral wounds |
|Fast-absorbing gut ||Monofilament heat treated to facilitate absorption ||Collagen derived from beef serosa or sheep submucosa ||5–7 d ||Absorbed by proteolytic processes in 21–42 d ||Moderate reactivity ||Facial wounds and skin grafts |
|Polyglycolic acid (Dexon®) ||Braided ||Glycolic acid polymer ||65% at 14 d and 35% at 21 d ||Absorbed by hydrolysis, complete by 60–90 d ||Minimal ||Subcutaneous approximation and ligation of vessels |
|Coated polyglactin 910 (Vicryl®) ||Braided ||Copolymer of lactide and glycolide, coated with polyglactin 370 and calcium stearate ||75% at 14 d and 40% at 21 d ||Absorbed by hydrolysis, complete by 56–70 d ||Minimal ||Subcutaneous approximation and ligation of vessels |
|Coated polyglactin 910 with triclosan (Vicryl PLUS®) ||Braided ||Copolymer of lactide and glycolide, coated with polyglactin 370 and calcium stearate; incorporates antibacterial agent triclosan ||75% at 14 d, 50% at 21 d, and 25% at 28 d ||Absorbed by hydrolysis, complete by 56–70 d ||Minimal ||Subcutaneous approximation and ligation of vessels, especially useful in contaminated wounds |
|Coated polyglactin 910 rapid absorption (Vicryl Rapide®) ||Braided ||Copolymer of glycolide and lactide, coated with polyglactin 370 and calcium stearate ||50% by 5 d and 0% at 14 d ||Absorbed by hydrolysis, complete by 42 d ||Minimal to moderate ||Skin approximation when absorbable sutures are used |
|Coated glycolide and lactide (Polysorb®) ||Braided ||Copolymer of glycolide and lactide, coated with mixture of caprolactone, glycolide copolymer, and calcium stearoyl lactylate ||80% at 14 d and 30% at 21 d ||Absorbed by hydrolysis, complete by 56–70 d ||Minimal ||Subcutaneous soft tissue approximation |
|Polydioxanone (PDS II®) ||Monofilament ||Polyester polymer ||70% at 14 d, 50% at 28 d, and 25% at 42 d ||Absorbed by hydrolysis, complete at 180–210 d ||Slight ||Subcutaneous soft tissue approximation where more prolonged strength is needed |
|Poliglecaprone 25 (Monocryl®) ||Monofilament ||Copolymer of glycolide and epsilon-caprolactone ||50–70% at 7 d and 20–40% at 14 d ||Absorbed by hydrolysis, complete by 91–119 d ||Minimal ||Subcutaneous soft tissue approximation |
|Poliglecaprone 25 with triclosan (Monocryl PLUS®) ||Monofilament ||Copolymer of glycolide and epsilon-caprolactone; incorporates antibacterial agent triclosan ||50–70% at 7 d and 20–40% at 14 d ||Absorbed by hydrolysis, complete by 91–119 d ||Minimal ||Subcutaneous soft tissue approximation; especially in contaminated wounds |
|Glycomer 631 (Biosyn®) ||Monofilament ||Polyester composed of glycolide, dioxanone, and trimethylene carbonate ||75% at 14 d and 40% at 21 d ||Absorbed by hydrolysis, complete by 90–110 d ||Slight ||Subcutaneous soft tissue approximation where extended strength is not needed |
|Polyglyconate (Maxon®) ||Monofilament ||Copolymer of glycolic acid and trimethylene carbonate ||80% at 7 d, 75% at 14 d, 65% at 21 d, 50% at 28 d, and 25% at 42 d ||Absorbed by hydrolysis, complete by 180 d ||Slight ||Subcutaneous soft tissue approximation where more prolonged strength is needed |
For most ED use, the choice between absorbable and nonabsorbable material for percutaneous sutures is clinically irrelevant.12,13,14,15 The cosmetic outcomes and complications of traumatic lacerations and surgical incisions closed with absorbable or nonabsorbable sutures have similar short- (infection, dehiscence) and long-term (cosmesis) outcomes.16 Absorbable sutures, like rapidly absorbing gut, are especially useful for skin closure in children who are not candidates for wound repair with skin tapes or tissue adhesives.
Suture material is categorized by the U.S. Pharmacopeia gauge size. The larger the suture size number, the thinner the suture, so that, for example, a 6-0 suture is thinner than a 5-0 suture. A general principle is that larger-diameter material produces more damage to the tissues and leaves larger holes in the skin, so generally thinner suture material is used whenever possible. Because smaller-diameter material has less strength, the trade-off is that more individual sutures closer together are sometimes needed to close a wound. Where cosmetic appearance is important, as on the face, smaller-diameter material is preferred (Table 41-4).
TABLE 41-4Recommended Suture Size Based on Laceration Location ||Download (.pdf) TABLE 41-4 Recommended Suture Size Based on Laceration Location
|Location ||Suture Size |
|Scalp ||3-0 or 4-0 |
|Face ||6-0 |
|Trunk ||4-0 |
|Extremities ||4-0 |
|Digits ||5-0 |
Improper tissue handling further traumatizes the tissues and results in an increased risk of infection and poor scarring.17 Gentle tissue handling using either skin hooks or the open limb of fine forceps is encouraged (Figure 41-1). Magnifying lenses such as surgical loupes can assist in accurate placement of sutures. While there are many types of surgical loupes available, a version useful in the ED is a magnifying power of 2.5× with the Keplerian lens system, which will provide a bright, clear image out to a field of view of 10 cm. Hemostasis is best achieved by direct pressure. Topical vasoconstrictors (such as epinephrine) applied to the wound edges and bed or mixed with the local anesthetic injected into the wound may help control bleeding in traumatic lacerations treated in the ED. With bleeding from vessels >2 mm in diameter, careful and selective placement of a ligature tie is often necessary. Electrocautery increases the risk of wound infection and scarring.17 The technique requires training and policies for its use, to ensure patient and healthcare professional safety.
The skin hook (A) or one limb of a tissue forceps with teeth (B) is used to elevate the wound edge to facilitate placement of the percutaneous suture.
The best cosmetic outcome is achieved by carefully matching each layer of the wound with its corresponding counterpart on the opposite side, ensuring eversion of the wound edges and minimizing the amount of tension on the wound. As the wound heals and the swelling subsides, the wound will eventually flatten, becoming flush with the surrounding skin surface. Inadvertent inversion of the wound edges may result in an unsightly depressed scar. A variety of suture techniques can be used to handle wounds of nearly all shapes, irregularities, and depths (Table 41-5).
TABLE 41-5Suture Techniques Based on Wound Type ||Download (.pdf) TABLE 41-5 Suture Techniques Based on Wound Type
|Suture Type ||Advantages ||Disadvantages ||Frequent Uses |
|Interrupted percutaneous ||Excellent approximation for irregular and complex lacerations || |
May strangulate tissues
May be used with deep sutures for high-tension wounds
|Continuous percutaneous || |
Less meticulous closure than interrupted sutures
Wound may dehisce if a single knot unravels and no deep sutures were placed
|Percutaneous closure in conjunction with deep sutures |
|Deep dermal || |
Reduces tension on wound surface
Allows early removal of percutaneous sutures, avoiding hatch marking
May reduce scar width
|May increase infection in contaminated wounds || |
Closure of dead space
|Continuous subcuticular || |
Reduces tension on wound surface
Reduces or eliminates need for percutaneous sutures
May reduce scar width
Less accurate approximation than interrupted sutures
Wound may dehisce if a single knot unravels
|Cosmetically visible areas to reduce scarring |
|Vertical mattress || |
Excellent wound edge eversion
Combines advantages of deep and superficial sutures
|May cause tissue strangulation || |
Thin or lax skin with little dermal or fascial tissue
High-tension areas (e.g., extremities)
|Horizontal mattress || |
More rapid than simple interrupted sutures
Avoids punctures close to wound edges that may impair perfusion
Accommodates wound swelling
|Requires skill to achieve wound edge eversion || |
Volar wounds of the hands
Initial approximation of high-tension wounds
|Half-buried horizontal mattress ||Less compromising to flap tip perfusion and stellate lacerations ||Technically difficult || |
Corner stitches and flaps
SIMPLE INTERRUPTED PERCUTANEOUS SUTURES
Individual simple interrupted percutaneous sutures are the most basic and most commonly used approach to close lacerations. Introduce the needle through the outer layer of the skin, and exit at the level of the dermis on one side of the wound. Then, reinsert the needle through the opposite wound edge starting at the level of the dermis and exit superficially (Figure 41-2). In order to ensure proper wound edge eversion, the needle should enter and exit the skin at equal distances from the wound and at an angle of 90 degrees. Wound edge eversion is achieved by taking a larger bite through the depth of the wound than through the more superficial layers (Figure 41-3).
Placement of simple interrupted percutaneous sutures. A. Insert the needle at a 90-degree angle to the skin. B. Drive the needle through the tissue until the tip exits the skin. C. Grasp the needle behind the tip and pull it through the wound. D. The suture should enter and exit the skin equidistant from the wound edges. E. Pull the suture to oppose the wound edges and cinch down the knot. F. Complete the knot to one side of the laceration. G. Apply additional sutures equidistant from each other until the wound is closed. [Reproduced with permission from Reichman EF, Simon RR (eds): Emergency Medicine Procedures. Copyright © 2004 by Eric F. Reichman, PhD, MD, and Robert R. Simon, MD. All rights reserved. Printed in the United States of America, Figure 78-6. By The McGraw-Hill Companies, Inc.]
Wound edge eversion. The distance of the suture from the wound edge is greater at the depth of the wound than at the surface, promoting wound edge eversion when tightened. [Reproduced with permission from Reichman EF, Simon RR (eds): Emergency Medicine Procedures. Copyright © 2004 by Eric F. Reichman, PhD, MD, and Robert R. Simon, MD. All rights reserved. Printed in the United States of America, Figure 41-77-8. By The McGraw-Hill Companies, Inc.]
The entrance and exit of the suture should be close enough to the wound edges that they are not puckered when the knot is tied but far enough away to allow the suture material a firm hold on the tissue. Sutures are tied using square knots, and, generally, the number of knot ties should correspond to the suture size (i.e., four ties for a 4-0 suture, five ties for a 5-0 suture, etc.). Additional ties do not increase the strength of a properly tied square knot; they only add to its bulk. The extra ties are to increase knot security and prevent unraveling. Once the knot is completed, it should be moved to one side of the wound so as to not rest directly over the edges. For simple linear lacerations, a useful approach is to place the first suture in the middle of the wound, creating two smaller segments that are sequentially bisected into smaller segments until adequate coaptation of the edges is achieved.
CONTINUOUS (RUNNING) PERCUTANEOUS SUTURES
The major advantage of this method is its rapidity, as the entire wound is closed before any of the suture material is cut. This technique is most appropriate for long linear lacerations. Because it does not allow for precise wound edge apposition, it should be avoided in irregularly shaped lacerations. With this method, the first suture is placed at one end of the laceration similarly to an interrupted percutaneous suture. After the knot is tied, the suture material is not cut, and the needle is reintroduced into the skin on the opposite side, pulling the suture across the wound at a 65-degree angle (Figure 41-4). The needle then crosses the depth of the wound in a circular motion perpendicular to the wound, exiting on the opposite side approximately 3 to 5 mm from the wound edge. This process is repeated as needed until the entire wound is approximated and a second knot is tied.
Continuous or running percutaneous suture. A. Place the initial stitch as a simple interrupted stitch, but do not cut the suture after the knot is securely tied. B and C. Place a second stitch 3 to 5 mm from the first stitch as if placing another simple interrupted stitch. D and E. Place a third stitch 3 to 5 mm from the second stitch and continue to place additional stitches until the end of the laceration is reached. F. Do not pull the last throw taut against the skin; the loop will act as the tail end of the suture for knot tying. G. Loop the needle end of the suture twice around the tip of the needle driver and grasp the last throw with the tips of the needle driver. H. Pull the last throw through the loops until the knot is against the skin. I. Perform three to five more instrument ties to secure the knot, and then cut off the excess suture. [Reproduced with permission from Reichman EF, Simon RR (eds): Emergency Medicine Procedures. Copyright © 2004 by Eric F. Reichman, PhD, MD, and Robert R. Simon, MD. All rights reserved. Printed in the United States of America, Figure 78-9. By The McGraw-Hill Companies, Inc.]
Deep dermal sutures are used to reduce tension on the wound and to close dead spaces. Placement of buried dermal sutures requires judgment because the benefits for nongaping small wounds are unproven and their presence may increase the risk of infection in contaminated wounds.18,19 Sutures through adipose tissue do not hold tension, are unnecessary in clean surgical cases, and only promote infection in contaminated wounds.19,20
With buried dermal sutures, the needle is first inserted at the level of the mid dermis on one side of the wound and then exits more superficially below the dermal–epidermal junction (Figure 41-5). The needle is then introduced below the dermal–epidermal junction on the opposite wound side and exits at the level of the mid dermis. Thus the knot becomes buried in the depth of the tissue when tying of the suture is completed. The first suture is placed at the center of the laceration, followed by additional sutures that sequentially bisect the wound. The number of buried sutures should be minimized.
Buried dermal suture. A. Insert the needle into one side of the base of the wound, and drive the needle from deep to superficial and exiting at the dermal–epidermal junction. B. Insert the needle through the dermal–epidermal junction on the opposite side of the wound and drive it through the base of the wound. The suture should exit the base of the wound across from and level with the entrance site of the first throw. C. Pull both free ends of the suture up and out through the laceration. D. Tie a knot in the suture. E. Pull both free ends of the suture to lower the knot to the base of the wound and oppose the tissue. Tie two additional knots to secure the suture. Cut off any excess suture. [Reproduced with permission from Reichman EF, Simon RR (eds): Emergency Medicine Procedures. Copyright © 2004 by Eric F. Reichman, PhD, MD, and Robert R. Simon, MD. All rights reserved. Printed in the United States of America, Figure 78-19. By The McGraw-Hill Companies, Inc.]
CONTINUOUS SUBCUTICULAR SUTURES
The continuous subcuticular suture is one of the more complex methods of wound closure. The major advantage of this method is that it results in fairly good wound approximation, often without requiring any percutaneous sutures. For this technique, after anchoring the absorbable suture at one end of the wound, sequential, horizontally oriented "bites" are taken immediately below the dermal–epidermal junction, working toward the other end until the wound is adequately approximated (Figure 41-6). The second knot is tied with the tails cut short so as to remain buried.
Continuous subcuticular sutures. A, B, and C. Place the first stitch into the dermis, just inside the laceration edge, as a buried knot. D. Place the continuous suture until the opposite end of the laceration is reached. E. The final throw should be left lax with a trailing loop of suture. F. The loop should be used as the "tail end" to perform an instrument tie. Tie three or four knots in the suture. Lift the free ends of the suture and cut them just above the knot. Apply adhesive tape across the laceration to help maintain the apposition of the wound. [Reproduced with permission from Reichman EF, Simon RR (eds): Emergency Medicine Procedures. Copyright © 2004 by Eric F. Reichman, PhD, MD, and Robert R. Simon, MD. All rights reserved. Printed in the United States of America, Figure 78-18. By The McGraw-Hill Companies, Inc.]
VERTICAL MATTRESS SUTURES
Vertical mattress sutures combine some of the advantages of deep and percutaneous sutures. They also result in excellent wound edge eversion. Vertical mattress sutures are particularly useful in very thin or lax skin and in areas where the deep subcutaneous tissues are too fragile to be used for anchoring tension-reducing sutures (e.g., over the shin). After taking a large, deep bite from both sides of the wound ("far to far"), the direction of the needle is reversed, and a smaller superficial bite is taken from both sides ("near to near") of the laceration (Figure 41-7). Vertical mattress sutures may result in excessive tension on the more superficial skin edges, which reduces blood supply to the skin and may result in necrosis of the wound margins.
Vertical mattress suture. A. The needle should enter and exit the skin 1.0 to 1.5 cm from the wound edge. B. The needle should traverse the base of the wound and grasp a large amount of tissue. C and D. Reverse the needle. The second throw should enter and exit the skin approximately 2 to 3 mm from the wound edge. The first and second throws must be directly over each other and parallel. E. Tie the suture to approximate the wound edges. The first throw will close the wound base and relieve the tension at the skin surface. The second throw approximates and everts the skin edges. [Reproduced with permission from Reichman EF, Simon RR (eds): Emergency Medicine Procedures. Copyright © 2004 by Eric F. Reichman, PhD, MD, and Robert R. Simon, MD. All rights reserved. Printed in the United States of America, Figure 78-11. By The McGraw-Hill Companies, Inc.]
A modification of the standard vertical mattress suture is the shorthand version. In this approach, the first throw is close to the wound edges ("near to near"); the suture is then grasped and pulled away from the wound, elevating the wound edges while a second throw is performed farther away from the wound ("far to far") (Figure 41-8).21 This shorthand version can be performed in less time with the same outcome; however, blind placement of the larger bite may injure underlying structures.
The "shorthand" vertical mattress suture. A and B. Place the first throw close to the lacerated wound edge to approximate the skin edges. C. Grasp and pull the suture to elevate the wound edges. This allows the needle to more easily take a large bite of tissue on the second throw. D. Place the second throw 1.0 to 1.5 cm from the wound edge. Release the suture. E. Tie the suture to approximate the wound edges and evert the skin surface. F. The final product looks exactly the same as the traditional vertical mattress suture. [Reproduced with permission from Reichman EF, Simon RR (eds): Emergency Medicine Procedures. Copyright © 2004 by Eric F. Reichman, PhD, MD, and Robert R. Simon, MD. All rights reserved. Printed in the United States of America, Figure 78-12. By The McGraw-Hill Companies, Inc.]
HORIZONTAL MATTRESS SUTURES
The horizontal mattress is a good suture technique to close wounds with poor circulation to the wound edges because no percutaneous punctures that could further disrupt skin perfusion are placed close to the wound edges. This suture also reduces tension at the wound edges and reduces the potential for subsequent local necrosis. Horizontal mattress sutures can close a wound with fewer individual stitches because each stitch encases more tissue than other techniques (Figure 41-9). This suture is useful on the volar surfaces of the hands and fingers, because these delicate skin areas may swell but the skin edges are not easily cut due to the placement of the skin punctures far from the wound. The main disadvantage of the horizontal mattress stitch is the skill required to place the suture to achieve wound eversion.
Horizontal mattress suture. A. The needle should enter and exit the skin 0.5 to 1.0 cm from the wound edge. B. The needle should traverse the base of the wound. C. Reverse the needle and make a second throw 0.5 cm from the first. D. The needle must enter and exit the skin and the wound edges so that the first and second throws are parallel to each other. E. Pull the free ends of the suture taut to oppose and evert the wound edges. F. The final result. [Reproduced with permission from Reichman EF, Simon RR (eds): Emergency Medicine Procedures. Copyright © 2004 by Eric F. Reichman, PhD, MD, and Robert R. Simon, MD. All rights reserved. Printed in the United States of America, Figure 78-14. By The McGraw-Hill Companies, Inc.]
HORIZONTAL HALF-BURIED MATTRESS SUTURES
Horizontal half-buried mattress sutures are particularly well suited for closing the tip of skin flaps and stellate lacerations because they minimize strangulation of the blood supply to the tip. The key to this stitch is that the needle and suture pass through the dermis of the tip and not the epidermis. The needle is introduced percutaneously through one side of the wound, then horizontally through the tip at the level of the dermis. The suture is completed by exiting the skin through the other side and tying the knot (Figure 41-10).
Half-buried horizontal mattress suture. A. To close a flap tip, place the first stitch percutaneously through the skin adjacent to the tip of the flap. Advance the needle through the dermal layer of the flap, the dermal layer of the skin adjacent to the tip of the flap, and out the skin adjacent to the tip of the flap opposite to where the stitch began. The needle must traverse the dermis of the flap and adjacent tissue at the same level of the dermis to properly approximate the wound edges. Gently pull on the free ends of the suture to approximate the flap against the adjacent skin edges. Tie and secure the suture in the usual manner. B. To close a stellate laceration, insert the needle through the skin of the largest flap. Advance the needle so that its tip exits the dermis. Continue to advance the needle through the dermis of each flap. The half-buried horizontal mattress stitch should encompass the tips of all the flaps. [Reproduced with permission from Reichman EF, Simon RR (eds): Emergency Medicine Procedures. Copyright © 2004 by Eric F. Reichman, PhD, MD, and Robert R. Simon, MD. All rights reserved. Printed in the United States of America, Figure 78-15. By The McGraw-Hill Companies, Inc.]