Enhancing Wound Closure On The Limbs

Vol.18, No. 8

August 1996

V

Continuing Education Article

FOCAL POINT ★ Simple wound management techniques sometimes make skin grafts or flaps unnecessary.

KEY FACTS ■ The simplest, least invasive, but most effective technique for closure of a limb wound under tension should be considered first. ■ Skin sutured too tightly around a leg can cause a “biological tourniquet.” ■ Onset of inflammatory or repair stages of healing can increase limb circumference, thus making it difficult to assess whether wound edges can be initially apposed. ■ Proper management of tension in a limb wound results in either wound closure or reduction of the size of needed skin grafts or flaps.

Enhancing Wound Closure on the Limbs Auburn University

M. Stacie Scardino, DVM Steven F. Swaim, DVM, MS

P

Ralph A. Henderson, DVM, MS Eric R. Wilson, DVM, MS

lanned or traumatic limb wounds that result in loss of tissue or excessive wound tension are a challenge for the veterinary practitioner. The first objective in early management of wounds is to preserve the blood supply and minimize foreign objects and pathogens so that tissue is suitable for apposition and healing. Traumatic wounds call for gentle technique that may include debridement, lavage, and possibly delayed primary closure. Some wound edges can easily be apposed early after the infliction of the wound. However, the onset of the inflammatory and repair stages of healing may increase limb circumference, thus making manual apposition of wound edges difficult or impossible. In other fresh wounds, it is obvious that the edges will never be apposed because of loss of tissue. For these wounds, some form of skin flap or graft is necessary for reconstruction. Other wounds may initially seem large because of primary skin retraction, but skin manipulation reveals sufficient skin for closure. This article discusses wounds that fall somewhere in between these two categories—wounds that cannot quite be closed. With proper management of tension, difficult limb wounds may be closed or made smaller to require a smaller flap or graft. Table I presents guidelines for the use of various techniques or combinations of techniques. When dealing with a limb wound under tension, the veterinarian should consider the simplest, least invasive, and yet most effective technique first; more involved techniques are used as needed. This article and Table I discuss techniques in the general order in which they should be considered for use. If the skin is pulled too tightly around a wound during wound closure, the circumferential skin tension (i.e., the “biological tourniquet”) impairs circulation distal to the wound closure, thus resulting in further swelling.1 If distal limb and paw edema or hypothermia are present, removal or loosening of tension sutures is indicated. A distal limb should not be jeopardized just to close a wound. Clinical judgment is important in making such assessments. Recently traumatized skin may have a compromised blood supply. Surgical manipulation should therefore be minimized until circulation improves.2,3 Added insult to an already weakened skin vasculature could result in sloughing. When the integrity of the skin vasculature is questionable, a bandage should be applied and wound closure delayed for 1 to 3 days.2 If the skin is severely trau-

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TABLE I Tension Management Techniques for Closure of Limb Wounds Technique a Undermining

Indications Wound edges appose or nearly appose under tension; most beneficial on proximal limb areas

Combinations b Before: Tension sutures, relaxing incisions, adjustable horizontal mattress suture (fresh wounds) After: Presutures

Skin-Stretching Sutures Presutures

Wound edges appose or nearly appose under tension; lesions (e.g., tumor) where postexcision wound closure will be under tension

Before: Undermining, tension sutures, relaxing incisions, adjustable horizontal mattress suture (fresh wounds)

Adjustable horizontal mattress sutures

Wound edges nearly appose or do not Before: Relaxing incisions appose under tension (fresh wounds or wounds in repair stage of healing); in place After: Undermining on fresh wounds; presutures of other tension sutures

Tension Sutures Intradermal

Wound edges appose under tension; patient is likely to molest the wound; in place of other skin sutures; under casts or splints where timed suture removal is impractical

Before: Other tension sutures; relaxing sutures

Far-near-near-far; far-far-near-near

Wound edges appose under tension; wounds with cyclic increases or decreases in tension with movement (flexion surfaces, foot pads)

Before: Relaxing incisions

Vertical mattress

Wound edges appose under tension

Before: Relaxing incisions

After: Undermining; presutures

After: Undermining; presutures; intradermal sutures

After: Undermining; presutures; intradermal sutures Relaxing Incisions Simple relaxing

Wound edges will almost appose under Before: Just before tension sutures tension; provides coverage for vital limb structures (e.g., tendons, ligaments, nerves, After: Presutures; undermining; adjustable horizontal mattress suture and vessels)

Multiple punctate incisions

Wound edges will almost appose under tension

Z-plasty

a The

Wound edges will almost appose under tension; skin is available in one direction for transposition to a perpendicular direction for wound closure—usually upper limb wounds

Simultaneous with: Intradermal sutures After: Presutures; undermining; adjustable horizontal mattress suture Before: Just before intradermal sutures After: Presutures; undermining; horizontal mattress sutures

main tension-management techniques (undermining, skin-stretching sutures, tension sutures, and relaxing incisions) are listed in the order in which they should be considered when one is dealing with tension wound closure on a limb. b The combinations are procedures that could be used in concert with other tension-management techniques. These are general guidelines; however, clinical judgment should be used when deciding on needs for any particular wound.

The Compendium August 1996

matized, it may be necessary to delay surgical manipulation to allow edema to resolve before the skin circulation has improved sufficiently to withstand wound closure. Clinical judgment is important in assessing the status of the skin circulation prior to wound closure.

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can be apposed or nearly apposed. Such suturing techniques include presutures and adjustable horizontal mattress sutures. Tension sutures are usually thought of as sutures that incorporate a larger quantity of skin and are able to overcome distraction forces at the wound edges. Suture patterns commonly used to overcome tension include far-near-near-far, far-farnear-near, and vertical mattress sutures.

UNDERMINING Undermining the skin adjacent to a wound is the simplest procedure for relieving tension when direct suturing results in too much Skin-Stretching Sutures tension during wound apPresutures position. Undermining frees Presutures are placed bethe skin from underlying Figure 1—Presutures. (A and B) The day before surgery, the tissue, thereby allowing the skin adjacent to the lesion is sutured over the lesion using a fore the wound is debrided full elastic potential of the Lembert suture pattern. (C) The following day, the presu- or a lesion (e.g., a tumor) is skin to be used as the skin is tures are removed and the lesion is excised. (D) The resulting excised. Presutures resemble defect or wound is closed using the stretched skin made a Lembert suture with bites stretched to cover a wound.1,2 available by the presutures. Because of the small amount on either side of the lesion. of skin on the limbs, underWhen placed several hours mining usually provides limited skin for reconstruction. before excision or debridement, the presutures stretch It is probably most beneficial on the proximal portion the skin, thus reducing the tension necessary to close the of the limbs, where there is more skin. wound.4–7 Presuturing is based on the skin’s biomechanical properties (creep and stress relaxation), which allow Undermining can be used in an attempt to gain as skin held under tension to gradually stretch beyond its much skin as possible for wound closure. It should be inherent extensibility.4–6,8 This technique is particularly considered when wound edges can be apposed or aluseful on the distal limbs, where the use of “walking” most apposed with tension. In fresh wounds, undersutures to overcome tension could result in encroachmining can be used before tension sutures, relaxing inment on the superficial vital structures in the area (i.e., cisions, or adjustable horizontal mattress sutures. It can vessels, nerves, and tendons).7 also be used after presutures. Presutures are indicated when wound edges can be The skin of the limbs should be undermined in the apposed or almost apposed with tension. This technique loose areolar fascia deep to the dermis.1–3 Blunt-tipped Metzenbaum scissors are almost universally used for can also be used in fresh wounds before undermining or undermining skin. Alternately opening and closing the before tension sutures, relaxing incisions, or adjustable scissor blades allows separation of the loose areolar conhorizontal mattress sutures are used. Signs of impaired nective tissue.2,3 For meticulous dissection around specirculation (i.e., edema or hypothermia) distal to the cific structures, sharp-sharp scissors are preferred. The presutures indicates that final wound closure may propoints engage the connective tissue with much less apduce a biological tourniquet. In such cases, gradual applied pressure, and the blades (when opened) bluntly plication of tension by an adjustable horizontal mattress separate the tissue.2 Sharp undermining may be persuture may be indicated to stretch the skin. As an alterformed by snipping the subcutaneous tissue with scisnative, the other tension closure techniques described in sor blades as they move throughout the tissue or by this article may be indicated for wound closure. cutting the subcutaneous tissue with a scalpel blade.1,2 Tranquilization and local analgesia are usually sufficient for placing presutures. Using 2-0 or 3-0 nonabSKIN-STRETCHING AND TENSION SUTURES sorbable suture material, the surgeon places suture bites Suture techniques may be used to relieve tension by in the skin 2 to 5 cm on either side of the lesion and gradually stretching the skin around a wound so that it exerts tension on adjacent skin (Figure 1A and 1B). CREEP ■ STRESS RELAXATION ■ INHERENT EXTENSIBILITY

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Figure 2A Figure 2C

Figure 2D Figure 2—Adjustable horizontal mattress suture. (A) This limb wound in the repair stage of healing will eventually heal without a graft or flap. An adjustable horizontal mattress suture will be used to enhance wound contraction. (B) Placement: a half-buried horizontal mattress suture starts the suture at one end. The suture is then advanced as an intradermal horizontal mattress suture with each bite slightly advanced. On the final bite, the needle is passed through the entire thickness of the skin and through a hole in a sterile button. After the wound edges are advanced as far as possible, two split shots are used to hold the suture tight (see inset). (C) Tightening: the suture is grasped with forceps and gently pulled. The split shots are pulled away from the button as the wound edges advance closer together. New split shots will be applied over the button. (D) After 7 days, the suture has resulted in almost complete wound apposition.

Figure 2B

The direction of the stretch is chosen according to the anticipated direction of least tension.6 The steep arc of the circumference of the limb of some small animals may interfere with the tightening of presutures.

Experiments on swine show that 40% less force is required to close a presutured wound than is required for a control wound.4 Another study performed on horses showed that a prolonged period (24 to 30 hours) of presuturing resulted in moderate edema that necessitated undermining. When presutures were placed for only

DIRECTION OF LEAST TENSION ■ EDEMA ■ UNDERMINING

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8 hours, wound closure was much easier.8 For dogs, presutures are placed late in the afternoon and then covered with a bandage. The following morning, the bandage and presutures are removed and definitive surgery is performed to remove a lesion and close the defect or to close a wound (Figure 1C and 1D).

cutting needle, the surgeon starts the horizontal mattress suture at one end of the defect. The suture is continued as an intradermal horizontal mattress suture, which tends not to interfere with the vasculature of the wound edge. Each bite is advanced slightly so that the suture passes at an angle across the wound. This technique allows the suture Adjustable Horizontal to slide through tissue easier Mattress Sutures when the suture is tightWe have used a continuened. If the wound is in the ous adjustable horizontal Figure 3—Intradermal sutures. Using 3-0 or smaller ab- repair stage of healing, care mattress suture to apply sorbable suture material in a continuous pattern, intradermal is taken not to disturb the gradual tension to wound sutures are placed in the dermis, with each bite being passed attachment of the skin to edges to aid wound contrac- horizontally. granulation tissue. tion. Continuous tension is At the last passage of the applied to wound edges that needle at the opposite end of cannot be initially closed the wound, the needle is because of tension. These passed through the entire are wounds that may eventhickness of the skin and tually close without a graft through a hole in a sterile or flap (Figure 2A). button. Traction on the suThe adjustable horizontal ture moves the wound edges mattress sutures are used in toward each other. Skin edge place of other tension suadvancement is maintained tures and have the advantage by the use of a small fishing that they can periodically be weight (adjustable split shot) tightened or loosened withplaced on the suture directly out the placement of new adjacent to the button. A secsutures. The adjustable horiond weight is placed against zontal mattress sutures the first one to prevent slipwould also be used after prepage (Figure 2B). Excess susutures, if presutures gave an ture material is cut off about indication that complete 5 cm (2 inches) beyond the wound closure would result weights, and a bandage is in impaired circulation (i.e., placed over the wound. if edema or hypothermia ocOn succeeding days, sucurred distal to the sutures). Figure 4—(A) Far-near-near-far and (B) far-far-near-near su- ture material beyond the Adjustable horizontal tures. These sutures are placed in the order that their names weights is grasped with formattress sutures may be imply, with each bite being taken on the opposite side of the ceps and gentle traction is placed early in wound man- wound. applied while the limb is agement or after the formasteadied. The fishing weights tion of granulation tissue. If they are placed early in are pulled away from the button, and the wound edges wound management, skin edges may be undermined can be observed advancing closer together (Figure 2C). prior to placement. However, the attachment of the Two additional weights are applied against the button to skin edge to granulation tissue should not be disturbed maintain suture advancement. The distance between the if the suture is placed during the repair stage of healing. original weights and the button gives an indication of Using synthetic 2-0 or 3-0 monofilament suture on a how far the edges of the wound have advanced. GRADUAL TENSION ■ TIGHTENING ■ LOOSENING ■ GRANULATION TISSUE

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When adjustable horizontal mattress sutures are used early in wound management, resolution of edema will enhance the amount of advancement of wound edges. Skin-edge advancement is greatest during the first 2 to 3 days because of inherent elasticity. When the wound edges are apposed or when they have advanced to their limit (i.e., tension does not result in further wound edge advancement), the suture is removed. Wound edges can often be advanced into apposition or near-apposition in a short time (Figure 2D). The suture may be loosened if the surgeon believes that it is too tight (e.g., if there were signs of impaired circulation distal to the wound). The weights would be removed and moved farther away from the button. A modified placement can be done by placing the fishing weight–button apparatus at both ends of the suture, thus permitting tightening from both ends. This technique is helpful for closing long wounds because the suture material slips through tissue less the further it is from the where the pull is applied. Thus, pulling at each end of the wound tends to distribute tension more evenly along the wound.

in the dermis and subcuticular sutures are placed under the dermis, in the subcutaneous tissue.9,10 Intradermal sutures are often used when wound edges can appose but with tension. They reduce the tension across the wound margin before skin sutures are placed5,9,11 or can be used in Figure 5—Vertical mattress suture. When used for tension re- lieu of skin sutures. Intraderlief, vertical mattress sutures are placed away from the skin mal sutures also help prevent edge. Soft latex rubber tubing is placed under the sutures to the widening of scars after removal of sutures if a nonabserve as stents. sorbable suture material is used. 1,2,11 If nonabsorbable material is to be used in light-skinned animals, an undyed material is preferred so that the sutures will not be visible through the skin. Intradermal sutures may be combined with simple skin apposition techniques or other tension-relieving techniques.2,5 They may be used after undermining or presutures and before other tension sutures are placed or relaxing incisions are made. In addition, intradermal tension sutures are much less prone than other types of tension suture to injury inflicted by the patient.2,9 These sutures should be considered when the patient may molest the wound. Intradermal sutures Figure 6—Simple relaxing incision. (A) The distance (B) be- are also preferred in lieu of tween the original wound and the relaxing incision should skin sutures under casts or equal the width (A) of the original wound. (B) When the appliances, when timed reoriginal wound is closed, the relaxing incision will be as large moval of sutures may be imas the original wound was before closure. (C) When two re- practical. laxing incisions are used, the distance (B) between the origiTension Sutures When used for wound nal wound and each relaxing incision should equal the width closure on the distal limbs Intradermal Sutures (A) of the original wound. (D) After the original wound is The terms intradermal su- closed, each of the two relaxing incisions will equal half of (where tension is a definite ture and subcuticular suture the width of the original wound. factor), an effort is made to are often used interchangeensure that these tension suably to describe sutures tures are placed in the derplaced either in the lower portion of the dermis or in mis rather than in the subcutis. If the skin is too thin the area of the dermis that blends into the subcutis.2,9 for the entire suture to be placed intradermally, a comBy definition, however, intradermal sutures are placed bined pattern beginning in the subcuticular zone, enSUBCUTICULAR ■ SUTURE ■ UNDYED MATERIAL ■ CASTS

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tering the dermis, and exiting at the subcuticular zone can be substituted. These sutures are placed with 3-0 or smaller absorbable suture material in a continuous pattern, with the needle passing horizontally with each suture bite4 (Figure 3). The pattern is the same as that used for an adjustable horizontal mattress suture. Figure 7—Multiple punctate relaxing incisions. (A) If the skin

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rubber tubing or buttons may be placed under the sutures. 1,2,5 Soft latex rubber tubing is preferred because it is more comfortable for the animal (Figure 5). When using such devices, the veterinarian should observe the wound daily because the pressure from the device may cause ischemic necrosis of the skin under the sutures. edges do not appose as a continuous intradermal suture is A continuous subcuticuplaced, multiple punctate relaxing incisions are made 1 cm lar suture and simple interFar-Near-Near-Far and Far-Far-Near-Near from the wound edge, 1 cm long and 0.5 cm apart in stag- rupted skin sutures may be gered, parallel rows. They may be placed bilaterally. (B) combined with the vertical Sutures Far-near-near-far and far- Once apposed, the skin edges are sutured routinely. (From mattress sutures to provide far-near-near sutures pro- Swaim SF, Henderson RA (eds): Small Animal Wound Man- final skin-edge apposiagement. Philadelphia, Lea & Febiger, 1990, p 105. Modified vide both tension relief and with permission.) tion. 2,5,10,12 Nonabsorbable 1,2,5,10,11 Far-near2-0 or 3-0 monofilament apposition. near-far and far-far-nearsuture material is usually near sutures are particularly good for closing wounds in used for these sutures. When used for tension relief, which tension increases or decreases cyclically during vertical mattress sutures should be placed before other movement (e.g., a flexion surface or a lacerated foot sutures rather than after the skin is closed. This order pad).2 These sutures can be used by themselves or after helps ensure that none of the underlying superficial vesundermining, presutures, or intradermal sutures. They sels, nerves, or tendons on the distal limb are incorposhould be considered before relaxing incisions are conrated into the sutures. sidered. RELAXING INCISIONS These sutures are usually placed with 2-0 to 4-0 nonIn general, relaxing incisions are indicated when the absorbable suture material in the order that their names wound edges are close to being apposed but the surimply, with each bite being taken on the opposite site of geon believes that apposition with tension sutures the wound. The far component acts as a tension suture, could produce enough tension to impair circulation. while the near component holds wound edges in apposiExamples include wounds for which presutures and adtion1,2,5,10,12 (Figure 4). When these sutures are used, excessive tightening should be avoided to prevent suturejustable horizontal mattress sutures have already been line inversion, which could impair healing.1,2,5,10,12 used without complete wound closure. Several forms of relaxing incisions can be used with the aforementioned Vertical Mattress tension-management techniques. Sutures When placed at a distance from the wound margins, Simple Relaxing Incisions A simple relaxing incision is made parallel and adjavertical mattress sutures serve as tension sutures.1,10 They could be used alone or after undermining, presutures, or cent to the wound, with intervening skin being used for intradermal sutures. They should be considered before wound closure. Thus, these incisions involve creating relaxing incisions are considered. Because of their conwounds to close wounds–which may cause the surgeon figuration, vertical mattress sutures do not tend to interand the pet owner some concern. The surgeon may fere with circulation as much as horizontal mattress sutherefore want to consider trying presutures, undermintures do; however, these sutures concentrate tension on ing, or an adjustable horizontal mattress suture first. If the skin near the wound edges, where pressure could be wound edges will almost appose with tension, a simple most detrimental to wound healing.1,2,13 When used for relaxing incision may be made prior to placement of tentension, they may be removed 3 to 4 days after placesion sutures. ment. Some wounds expose tendons, ligaments, nerves, The tension required to close some wounds would and vessels. Such exposure justifies primary closure cause the suture to tear the skin. In these cases, stents of with the aid of a relaxing incision in exchange for a deSTENTS ■ RUBBER TUBING ■ BUTTONS ■ EXPOSED TISSUE

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Figure 8A

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Figure 8B

Figure 8C

during healing to ensure that a biological tourniquet does not result from contraction and epithelialization. When making the incision, the surgeon should ensure that the width of skin between the relaxing incision and the wound is equal to the width of the wound. After undermining the skin between the wound and the incision, the bipedicle flap of skin is advanced over the wound1,2,5,11,13 (Figure 6A and 6B). When only one relaxing incision is used, the defect remaining after closure of the original wound is about as large as the original wound. When relaxing incisions are created on both sides of a wound, the width of each flap (distance of incision from wound) should equal the widest part of the deFigure 8D Figure 8E fect. Closure results in two smaller deFigure 8—Z-plasty. (A) An open wound on the craniolateral aspect of the proximal fects that are allowed to heal as open forelimb. (B) Pinching skin proximal to the lesion proximodistally reveals insuffiwounds5,8 (Figure 6C and 6D). cient laxity. (C) Pinching skin craniocaudally reveals sufficient skin laxity. (D) Zplasty designed adjacent to the wound to move skin from craniocaudal plane to the proximodistal plane for wound closure. (E) Wound closed using Z-plasty proximally Multiple Punctate Relaxing Incisions and multiple punctate incisions distally.

fect in a relatively unobtrusive location. If the incision is in healthy skin, it usually heals uneventfully.1,2,5,11,13 Because the amount of skin available for wound closure is limited on the limbs, the wound should be watched

Multiple punctate relaxing incisions are small parallel staggered incisions made in the skin adjacent to a wound to release tension in wound closure.2,5,7,13,14 Multiple punctate relaxing incisions break up the relaxing incision into many small incisions that are more cosmetic and heal

BIOLOGICAL TOURNIQUET ■ BIPEDICLE FLAP ■ WIDTH OF DEFECT

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Figure 9—Z-plasty. (A) A Z-plasty with all three limbs of equal length and 60˚ angles is made adjacent to the defect, with the central limb of the Z in the direction of needed relaxation. (B) The flaps of the Z and skin between the Z-plasty and the wound are undermined. (C) The wound is closed. The flaps of the Z-plasty tend to realign themselves as the wound is closed. (D) The Z-plasty is sutured using half-buried horizontal mattress sutures for the flap tips. The central limb of the Z-plasty is now aligned perpendicular to its original direction.

faster than one large relaxing incision and are usually more acceptable to the animal’s owner.2,7,14 However, they may not provide as much relaxation as is attained with one large relaxing incision.4,15,16 As with simple relaxing incisions, the surgeon may want to try presutures, undermining, or an adjustable horizontal mattress suture before using multiple punctate relaxing incisions. A study evaluating the extent (width) of the skin defect (in relation to the circumference of the leg) that could be closed using multiple punctate relaxing incisions showed healing to be very cosmetic in those defects that comprised one fourth of the circumference of the limb. Healing was satisfactory but less cosmetic when the defect was two sevenths of the limb circumference. When the defect was one third of the limb circumference, healing was complete but cosmetic appearance was poor.15 The incisions are usually 1 cm from the wound edge, 1 cm long, and 0.5 cm apart in staggered parallel rows. A continuous absorbable intradermal suture is placed. If the skin edges do not appose as the suture is placed and tightened (or if they appose with tension), punctate relaxing incisions are made in the skin adjacent to the wound edges on both sides of the wound.2,7,16 Once apposed, the skin is sutured routinely (Figure 7). Another technique for performing the procedure involves placing the continuous intradermal absorbable suture along the length of the wound but not tightening or tying it at one end. While tension is held on the free end of the suture, hemostats are placed under a loop of suture near its origin and lifted. If the skin

edges do not appose, punctate incisions are made bilaterally in the area of tension. The hemostats are placed under another loop of suture, and the procedure is repeated until the wound is closed along its entire length.2,7,13 No more punctate incisions should be made than are necessary to allow wound closure without tension.2,7 The larger the relaxing incisions and the more incisions that are made, the greater the skin relaxation; however, the chance of damaging the skin vasculature and causing necrosis also increases.2,7,13,14

Z-Plasty Z-plasty is the transposition of two interdigitating triangular flaps of skin; it allows a gain in length or relaxation in one direction due to shortening of the skin in the opposite direction.1,2,5 Before using a Z-plasty as a relaxing incision, the surgeon should manipulate the skin around the wound to ensure that there will be sufficient skin in one direction to allow the needed relaxation in the perpendicular direction1,2,5,17 (Figure 8A through 8C). Theoretically, if all limbs of the Z-plasty are of equal length and the angles are at 60˚, there should be a 75% gain in length as the flaps are transposed.2,5,13,17 However, the actual gain from a Z-plasty is determined by the skin and scar tissue where it is performed.5,13,17 Again, the surgeon may want to try presutures, undermining, or an adjustable horizontal mattress suture before using a Z-plasty relaxing incision. When a Z-plasty is used as a relaxing incision, all of the limbs of the Z should be of equal length; 60˚ angles

APPOSITION ■ COSMESIS ■ SKIN VASCULATURE

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are made adjacent to the defect, with the central limb of the Z in the direction in which relaxation is needed1,2,5,13,17 (Figures 8D and 9A). After the Z is incised, its flaps and the skin between the Z and the wound are undermined (Figure 9B). The original wound should be closed before the Z-plasty. Tacking sutures may be used to help close dead space between the Z-plasty and the wound, if necessary.1,2,5 Depending on the amount of tension associated with closure, simple interrupted 3-0 nonabsorbable skin sutures may be sufficient by themselves, or they may be used in conjunction with a continuous 3-0 absorbable intradermal suture if tension is a factor. As the wound is closed, the flaps of the Z-plasty tend to transpose themselves and lie in their new position for final suturing (Figure 9C). The Z-plasty defect is then sutured using half-buried horizontal mattress sutures to suture the tips of the flaps in place.1,2 If the procedure has been performed correctly, the central limb of the Z will be aligned perpendicular to its original direction (i.e., it will be parallel to the long axis of the wound (Figures 8E and 9D).

About the Authors Drs. Scardino and Swaim are affiliated with the ScottRitchey Research Center and Drs. Swaim, Henderson, and Wilson with the Department of Small Animal Surgery and Medicine, College of Veterinary Medicine, Auburn University, Alabama. Dr. Henderson is a Diplomate of the American College of Veterinary Surgeons.

REFERENCES 1. Swaim SF: Management of skin tension in dermal surgery. Compend Contin Educ Pract Vet 2(10):758–766, 1980.

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2. Swaim SF, Henderson RA: Management of skin tension, in Swaim SF, Henderson RA (eds): Small Animal Wound Management. Philadelphia, Lea & Febiger, 1990, pp 87–106. 3. Pavletic MM: Undermining for repair of large skin defects in small animals. Mod Vet Pract 67:13–20, 1986. 4. Liang MD, Briggs P, Heckler FR, Futrell J: Presuturing—A new technique for closing large skin defects: Clinical and experimental studies. Plast Reconstr Surg 81(5):694–702, 1988. 5. Swaim SF: Principles of plastic and reconstructive surgery, in Slatter DH (ed): Textbook of Small Animal Surgery, ed 2. Philadelphia, WB Saunders Co, 1993, pp 280–294. 6. Harrison IW: Presuturing as a means of reducing skin tension in excisional biopsy wounds in four horses. Cornell Vet 81:351–356, 1991. 7. Swaim SF, Scardino MS: Selected paw and distal limb salvage and reconstructive surgery techniques, in Bojrab MJ (ed): Current Techniques in Small Animal Surgery, ed 4. Baltimore, Williams & Wilkins, in press. 8. Bigbie R, Shealy P, Moll D, Gragg D: Presuturing as an aid in the closure of skin defects created by surgical excision. Proc AAEP :613–624, 1990. 9. Smeak DD: Buried continuous intradermal suture closure. Compend Contin Educ Pract Vet 14(7):907–919, 1992. 10. Stashak TS: Selection of suture materials and suture patterns for wound closure, in Stashak TS (ed): Equine Wound Management. Philadelphia, Lea & Febiger, 1991, pp 52–69. 11. Johnston DE: Tension-relieving techniques. Vet Clin North Am Small Anim Pract 20:67–80, 1990. 12. Stashak TS: Reconstructive surgery in the horse. JAVMA 170:143–149, 1977. 13. Pavletic MM: Tension-relieving techniques, in Pavletic MM (ed): Atlas of Small Animal Reconstructive Surgery. Philadelphia, JB Lippincott Co, 1993, pp 146–182. 14. Swaim SF: Wound management of the distal limbs and paws. Vet Med Rep 2:128–139, 1990. 15. Vig MM: Management of integumentary wounds of extremities in dogs: An experimental study. JAAHA 21:187–192, 1985. 16. Swaim SF: Paw salvage and reconstruction techniques for dogs and cats. Proc AAHA 58th Annu Meet:182–187, 1991. 17. Vig MM: Management of experimental wounds of the extremities in dogs with Z-plasty. JAAHA 28:553–559, 1992.

TACKING SUTURES ■ DEAD SPACE ■ INTRADERMAL SUTURE