Suturing Techniques 

Updated: Jul 10, 2018
Author: Julian Mackay-Wiggan, MD, MS; Chief Editor: Dirk M Elston, MD 

Overview

Background

As a method for closing cutaneous wounds, the technique of suturing is thousands of years old. Although suture materials and aspects of the technique have changed, the primary goals remain the same, as follows:

  • Closing dead space

  • Supporting and strengthening wounds until healing increases their tensile strength

  • Approximating skin edges for an aesthetically pleasing and functional result

  • Minimizing the risks of bleeding and infection

The postoperative appearance of a beautifully designed closure or flap can be compromised if an incorrect suture technique is chosen or if the execution is poor. Conversely, meticulous suturing technique cannot fully compensate for improper surgical technique. Poor incision placement with respect to relaxed skin tension lines, excessive removal of tissue, or inadequate undermining may limit the surgeon’s options in wound closure and suture placement. Gentle handling of the tissue is also important to optimize wound healing.

The choice of suture technique depends on the following:

  • Type and anatomic location of the wound

  • Thickness of the skin

  • Degree of tension

  • Desired cosmetic result

Proper placement of sutures enhances the precise approximation of the wound edges, which helps minimize and redistribute skin tension. Wound eversion is essential to maximize the likelihood of good epidermal approximation. Eversion is desirable to minimize the risk of scar depression secondary to tissue contraction during healing. Usually, inversion is not desirable, and it probably does not decrease the risk of hypertrophic scarring in an individual with a propensity for hypertrophic scars.

The elimination of dead space, the restoration of natural anatomic contours, and the minimization of suture marks are also important to optimize the cosmetic and functional results.

In this article, the techniques of suture placement for various types of stitch are described, the rationale for choosing one suture technique over another is reviewed, and the advantages and disadvantages of each suture technique are discussed. Frequently, more than one suture technique is needed for optimal closure of a wound. After reading this article, the reader should have an understanding of how and why particular sutures are chosen and an appreciation of the basic methods of placing each type of suture.[1, 2]

Indications

Simple interrupted suture

Compared with running (continuous) sutures, interrupted sutures are easy to place, have greater tensile strength, and have less potential for causing wound edema and impaired cutaneous circulation. Interrupted sutures also allow the surgeon to make adjustments as needed to properly align wound edges as the wound is sutured.

Disadvantages of interrupted sutures include the length of time required for their placement and the greater risk of crosshatched marks (ie, train tracks) across the suture line. The risk of crosshatching can be minimized by removing sutures early to prevent the development of suture tracks.

Simple running suture

Running sutures are useful for long wounds in which wound tension has been minimized with properly placed deep sutures and in which approximation of the wound edges is good. This type of suture may also be used to secure a split- or full-thickness skin graft. Theoretically, less scarring occurs with running sutures than with interrupted sutures because fewer knots are made with simple running sutures; however, the number of needle insertions remains the same. Both basting sutures and tie-over bolsters have been used to help secure skin grafts.[3]

Advantages of the simple running suture over simple interrupted sutures include quicker placement and more rapid reapproximation of wound edges. Disadvantages include possible crosshatching, the risk of dehiscence if the suture material ruptures, difficulty in making fine adjustments along the suture line, and puckering of the suture line when the stitches are placed in thin skin.

Running locked suture

Locked sutures have increased tensile strength; therefore, they are useful in wounds under moderate tension or in those requiring additional hemostasis because of oozing from the skin edges.

Running locked sutures have an increased risk of impairing the microcirculation surrounding the wound, and they can cause tissue strangulation if placed too tightly. Therefore, this type of suture should be used only in areas with good vascularization. In particular, the running locked suture may be useful on the scalp or in the postauricular sulcus, especially when additional hemostasis is needed.

Vertical mattress suture

A vertical mattress suture is especially useful in maximizing wound eversion, reducing dead space, and minimizing tension across the wound. One of the disadvantages of this suture is crosshatching. The risk of crosshatching is greater because of increased tension across the wound and the four entry and exit points of the stitch in the skin.

The recommended time for removal of this suture is 5-7 days (before formation of epithelial suture tracks is complete) to reduce the risk of scarring. If the suture must be left in place longer, bolsters may be placed between the suture and the skin to minimize contact. The use of bolsters minimizes strangulation of the tissues when the wound swells in response to postoperative edema. Placing each stitch precisely and taking symmetric bites is especially important with this suture.

Half-buried vertical mattress suture

The half-buried vertical mattress suture is used in cosmetically important areas such as the face.

Pulley suture

The pulley suture facilitates greater stretching of the wound edges and is used when additional wound closure strength is desired.

Far-near near-far modified vertical mattress suture

The far-near near-far modification of the vertical mattress suture, which basically functions as a pulley suture, is useful when tissue expansion is desired, and it may be used intraoperatively for this purpose. This suture is also useful when one is beginning the closure of a wound that is under significant tension. Placing pulley stitches first allows the wound edges to be approximated, thereby facilitating the placement of buried sutures.

When wound closure is complete, the pulley stitches may be either left in place or removed if wound tension has been adequately distributed after placement of the buried and surface sutures.

Horizontal mattress suture

The horizontal mattress suture is useful for wounds under high tension because it provides strength and wound eversion. This suture may also be used as a stay stitch for temporary approximation of wound edges, allowing placement of simple interrupted or subcuticular stitches. The temporary stitches are removed after the tension is evenly distributed across the wound.

Horizontal mattress sutures may be left in place for a few days if wound tension persists after placement of the remaining stitches. In areas of extremely high tension at risk for dehiscence, horizontal mattress sutures may be left in place even after removal of the superficial skin sutures. However, they have a high risk of producing suture marks if left in place for longer than 7 days.

Horizontal mattress sutures may be placed before a proposed excision as a skin expansion technique to reduce tension. Improved eversion may be achieved with this stitch in wounds without significant tension by using small bites and a fine suture.

In addition to the risk of suture marks, horizontal sutures have a high risk of tissue strangulation and wound edge necrosis if tied too tightly. Taking generous bites, using bolsters, and cinching the suture only as tightly as necessary to approximate the wound edges may decrease the risk, as does removing the sutures as early as possible. Placing sutures at a greater distance from the wound edge facilitates their removal.

Half-buried horizontal suture

The half-buried horizontal suture (also referred as the tip stitch or three-point corner stitch) is used primarily to position the corners and tips of flaps and to perform M-plasties and V-Y closures. The corner stitch may provide increased blood flow to flap tips, lowering the risk of necrosis and improving aesthetic outcomes.[4] However, in larger flaps with greater tension, this technique has been reported to position the flap tip deeper than the surrounding tissue, often resulting in a depressed scar.[5, 6]

Absorbable buried suture

Absorbable buried sutures are used as part of a layered closure in wounds under moderate-to-high tension. Buried sutures provide support to the wound and reduce tension on the wound edges, allowing better epidermal approximation of the wound. They are also used to eliminate dead space, or they are used as anchor sutures to fix the overlying tissue to the underlying structures. Wounds under significant tension may benefit from the use of a subcutaneous inverted cross-mattress stitch (SICM stitch), which can approximate such wounds relatively easily via a lateral pulley effect.[7, 8]

Dermal-subdermal suture

A buried dermal-subdermal suture maximizes wound eversion. It is placed so that the suture is more superficial away from the wound edge.

Buried horizontal mattress suture

The buried horizontal mattress suture is used to eliminate dead space, reduce the size of a defect, or reduce tension across wounds.[9]

Running horizontal mattress suture

The running horizontal mattress suture is used for skin eversion. It is useful in areas with a high tendency for inversion, such as the neck. It can also be useful for reducing the spread of facial scars. If the sutures are tied too tightly, tissue strangulation is a risk. Although it is slightly more time-consuming to place, this suture appears to result in smoother and flatter scars than a simple running suture.[10] A modification of the horizontal running suture with intermittent single loops was recently reported to avoid the characteristic track marks resulting from suture tension while increasing wound eversion.[11] Other modifications include the V-shaped Victory stitch.[12]

Running subcuticular suture

The running subcuticular suture is valuable in areas where tension is minimal, dead space has been eliminated, and the best possible cosmetic result is desired.[13] Because the epidermis is penetrated only at the beginning and end of the suture line, the subcuticular suture effectively eliminates the risk of crosshatching.

The suture does not provide significant wound strength, though it does precisely approximate the wound edges. Therefore, the running subcuticular suture is best reserved for wounds in which the tension has been eliminated with deep sutures, and the wound edges are of approximately equal thicknesses.

Running subcutaneous suture

The running subcutaneous suture is used to close the deep portion of surgical defects under moderate tension. It is used in place of buried dermal sutures in large wounds when a quick closure is desired. Disadvantages of running subcutaneous sutures include the risk of suture breakage and the formation of dead space beneath the skin surface. Modifications of this suture have been recently described, which reportedly allows for consistent eversion and excellent cosmetic results in challenging high-tension areas.[14, 15]

Running subcutaneous corset plication stitch

The corset plication technique is used in wounds wider than 4 cm that are under excess tension. It creates natural eversion and better wound edge approximation. This technique eases subsequent placement of intradermal sutures, in that wound diameter and tension are significantly reduced.

The strength of the suture relies on inclusion of the septations from the fascial layer beneath the subcutaneous tissue. If tissue ruptured postoperatively, tension would be distributed more broadly. Potential problems include suture breakage and wound distortion.[16]

Modified half-buried horizontal mattress suture

The modified corner stitch allows equal eversion of the flap tip edges and improved aesthetic outcomes. Although it may increase risk of necrosis if tied too tightly, a study by Bechara et al suggested that the incidence of flap tip necrosis was comparable with that of the traditional corner stitch.[6]  Modified subcutaneous buried horizontal mattress sutures relieve more wound tension and have a lower risk of dehiscence compared with vertical buried mattress sutures.[17]

Deep tip stitch

The deep tip stitch is used for M-plasty, W-plasty flaps, and V-Y closures to increase wound eversion. It provides longer-term support to the flap than the traditional corner stitch does and improves alignment of the tip with the sides of closure. This technique also avoids surface sutures, decreasing the risk of track marks. Flap tip necrosis and complications were comparable to that of standard sutures.[5]

Technical Considerations

Best practices

Effective suturing technique depends on appropriate selection of sutures, surgical gloves, needles, and needle holders (see Equipment).

Suture selection

Much of the process surrounding suture selection depends on surgeon training and preference. A wide variety of suture materials are available for each surgical location and surgical requirement. Generally, the surgeon selects the smallest suture that adequately holds the healing wound edges. The tensile strength of the suture should never exceed the tensile strength of the tissue. As the wound heals, the relative loss of suture strength over time should be slower than the gain of tissue tensile strength.

Certain general principles can be applied to suture selection. Sutures are no longer needed when a wound has reached maximum strength. Therefore, nonabsorbable suture should be considered in skin, fascia, and tendons (slowly healing tissues), whereas mucosal wounds (rapidly healing tissues) may be closed with absorbable sutures.

Aesthetic concerns are at a premium in regions of the head and neck such as the eyelid, periorbital area, nose, pinna, lip, and vermillion. In these areas, tensile strength requirements tend to be less, and smaller suture sizes are preferred. However, the mobility of the lip and vermillion requires a relatively higher suture tensile strength.

The activity and mobility of the face, anterior and posterior neck, scalp, superior trunk, and nasal and oral mucosa demand higher tensile strength requirements in suture selection. Additionally, major musculocutaneous flaps tend to be closed under significant tension, requiring maximal long-term tensile strength.

Because the presence of foreign bodies in contaminated tissues may facilitate infection, special consideration of suture selection in these locations (eg, a contaminated posttraumatic wound) is imperative. Multifilament sutures are more likely to harbor contaminants than monofilament sutures are; accordingly, monofilament sutures are generally preferable in potentially contaminated tissues. The smallest inert monofilament suture materials (eg, nylon or polypropylene) should be sued in this setting.

The optimal suture size is generally the smallest size that can still effectively achieve the desired tension-free closure. If wound tension is high, smaller-diameter sutures may actually injure tissues by cutting through them. Therefore, the tensile strength of the suture and that of the tissue should be closely matched.

Surgical glove selection

Surgeons who use sutures and needles should wear sterile surgical gloves without cornstarch, which has been shown to promote wound infection, cause serious peritoneal adhesions and granulomatous peritonitis, and act as a well-documented vector of the latex allergy epidemic. In 2008, 13 health professionals filed a citizen’s petition to the US Food and Drug Administration (FDA) to ban cornstarch powder on medical gloves.[18]

The FDA allows 1.5% of the surgical gloves to have holes, and these holes allow the transmission of blood and thus of potentially deadly bloodborne viral infections between patient and surgeon. After surgery has begun, a major cause of glove holes is surgical needle penetration through the glove. Consequently, the double-glove Biogel Puncture Indication System should be used to detect the location and presence of holes in the gloves, allowing the surgeon to change the gloves when a hole is detected (see the image below).[19]

Poster for Biogel Puncture Indication System. Poster for Biogel Puncture Indication System.

Needle selection

No standardized sizing system or nomenclature is available for needles. The main consideration in needle selection is to minimize trauma. A taper-point needle is sufficient for tissues that are easy to penetrate. Cutting needles are typically reserved for tough tissues. As a general rule, taper-point needles may be used for all closures except skin sutures. The length, diameter, and curvature of the needle influence the surgeon’s ability to place a suture. Ideally, the needle-body diameter matches the suture size.

Needle-holderselection

No standardized sizing system or nomenclature is available for needle holders. Needle control and performance is affected by the stability of the needle within the needle holder; thus, for a secure needle hold and prevention of rocking, turning, and twisting, the jaws of the needle holder must be appropriate to the needle size. Often, the surface contact with the needle-holder jaws and the bending moment of the needle are maximized with an ovoid cross-section of the needle body.

In addition, the handle of the needle holder must be appropriate for the depth needed for the suture placement. A mechanical advantage for exerting force through the needle point is created by the difference between the length of the handle and the jaw.

The needle-holder clamping moment is a measure of the force applied to a suture needle by the needle holder, and the needle-yield moment is the amount of deformation that can occur before a needle is permanently deformed. Thus, when the needle-holder clamping moment is greater than the needle-yield moment, the needle is likely to be permanently deformed, which may lead to complications.

Outcomes

A study by Lin et al found the handling characteristics of Polysorb sutures to be superior to those of polyglactin 910 (Vicryl) sutures.[20] With comparable knot construction and suture sizes, the knot-breaking strength of Polysorb sutures was significantly greater than that of polyglactin 910 sutures. In addition, the mean maximum knot rundown force noted with Polysorb sutures was significantly lower than that noted with polyglactin 910 sutures, facilitating knot construction.

Drake et al used a miniature swine model to study the determinants of suture extrusion after subcuticular closure by synthetic braided absorbable sutures in dermal skin wounds.[21] Standard, full-thickness skin incisions were made on each leg and abdomen. The wounds were closed with either Polysorb or polyglactin 910 sutures.

Each of the skin incisions was closed with five interrupted subcuticular vertical, loops secured with a surgeon’s knot.[21] The loops were secured with three-throw knots in one pig, four-throw knots in the second pig, and five-throw knots in the third pig. Suture extrusion, wound dehiscence, stitch abscess, and granuloma formation were all observed.

The cumulative incidence of suture extrusion over 5 weeks ranged from 10% to 33%. Polyglactin 910 sutures had a higher cumulative incidence of suture extrusion than Polysorb sutures did (31% vs 19%).[21] With Polysorb sutures, the five-throw surgeon’s knot had a higher cumulative incidence of suture extrusion than the three-throw or four-throw surgeon’s knot (30% vs 17% and 10%, respectively).

When Sanz et al randomly assigned 210 rats into one of five study groups to compare polytrimethylene carbonate (Maxon) with three absorbable sutures (polyglactin 910, chromic catgut, and polydioxanone [PDS II]) with respect to tissue inflammatory reaction, knot security, suture tensile strength, and suture absorption, Maxon and PDS II elicited a lower degree of chronic inflammation than polyglactin 910 and chromic catgut did.[22]

In addition, the tensile strengths of Maxon and polyglactin 910 significantly exceeded those of PDS II and chromic catgut during the critical period of wound healing.[22] Maxon and PDS II retained a larger percentage of tensile strength during the long postoperative period, whereas polyglactin 910 and chromic catgut were mostly absorbed. The investigators concluded that Maxon was an excellent addition to the armamentarium of the surgeon.

A randomized control study of the barbed suture (V-Loc) confirmed the unique performance of this suture for gastrointestinal (GI) wound closure.[23] The V-Loc wound closure device appeared to offer GI closure comparable to that achieved with 3-0 Maxon while being significantly faster. However, further studies with V-Loc are required to evaluate its use in laparoscopic surgery.

When Pineros-Fernandez et al compared the biomechanical performance of polyglytone 621 (Caprosyn) suture with that of chromic gut suture, both suture types provided comparable resistance to wound disruption.[24] The biomechanical performance studies included quantitative measurements of wound security, strength loss, mass loss, potentiation of infection, tissue drag, knot security, and knot rundown, as well as suture stiffness.

Before implantation, suture loops of Caprosyn had significantly greater mean breaking strength than suture loops of chromic gut did[24] ; 3 weeks after implantation of these absorbable suture loops, the sutures had no appreciable strength. The rate loss of suture mass of these two sutures was similar.

As expected, chromic gut sutures potentiated significantly more infection than Caprosyn sutures did.[24] However, the handling properties of Caprosyn sutures were far superior to those of chromic gut sutures, and the smooth surface of the Caprosyn sutures encountered lower drag forces than the chromic gut sutures did. Furthermore, it was much easier to reposition the Caprosyn knotted sutures than the knotted chromic gut sutures. In the case of chromic gut sutures, it was not possible to reposition a two-throw granny knot.

These biomechanical performance studies demonstrated the superior performance of the synthetic Caprosyn sutures compared with chromic gut sutures and provided compelling evidence of why Caprosyn sutures are an excellent alternative to chromic gut sutures.

 

Periprocedural Care

Equipment

Equipment required for suture closure of a wound includes the following:

  • Suture material

  • Needle

  • Needle holder

Suture material is a foreign body implanted into human tissues; consequently, it elicits a foreign-body tissue reaction. During wound closure, a sterile field and meticulous aseptic technique are critical to minimize the risk of wound infection. Other complications of wound healing, such as hypertrophic scars, wide scars, and wound dehiscence, may result from patient factors (eg, nutritional status), incorrect suture selection, or a technique that results in excessive tension across the wound.

Surgical needles are produced from stainless steel alloys, which have excellent resistance to corrosion.[25] All true stainless steels contain a minimum of 12% chromium, which allows a thin, protective surface layer of chromium oxide to form when the steel is exposed oxygen. Since their development during the early 1960s, high-nickel maraging stainless steels have found extensive use in structural materials in many applications that require a combination of high strength and toughness.

Wound closure and healing are affected by the initial tissue injury caused by needle penetration and subsequent suture passage. Needle selection, surface characteristics of the suture (eg, coefficient of friction), and suture-coating materials selected for wound closure are important factors that must be considered by the surgeon.

Suture qualities

The ideal suture material would have all of the following characteristics:

  • It is sterile

  • It is suitable for all purposes (ie, is composed of material that can be used in any surgical procedure)

  • It causes minimal tissue injury or tissue reaction (ie, is nonelectrolytic, noncapillary, nonallergenic, and noncarcinogenic)

  • It is easy to handle

  • It holds securely when knotted (ie, no fraying or cutting)

  • It has high tensile strength

  • It possesses a favorable absorption profile

  • It is resistant to infection

At present, unfortunately, no single material is available that can offer all of these characteristics. In different situations and in different areas of the body where tissue composition varies, different suture characteristics are required for adequate wound closure.

There are several fundamental and essential characteristics that all sutures should be manufactured to possess, as follows:

  • Sterility

  • Uniform diameter and size

  • Pliability for ease of handling and knot security

  • Uniform tensile strength by suture type and size

  • Freedom from irritants or impurities that would elicit tissue reaction

In addition, there are various characteristics of suture material that are described with the following terms:

  • Absorbable - Progressive loss of mass or volume of suture material; this does not correlate with initial tensile strength

  • Breaking strength - Limit of tensile strength at which suture failure occurs

  • Capillarity - Extent to which absorbed fluid is transferred along the suture

  • Elasticity - Measure of the ability of the material to regain its original form and length after deformation

  • Fluid absorption - Ability to take up fluid after immersion

  • Knot-pull tensile strength - Breaking strength of knotted suture material (10-40% weaker after deformation by knot placement)

  • Knot strength - Amount of force necessary to cause a knot to slip (this is related to the coefficient of static friction and plasticity of a given material)

  • Memory - Inherent capability of suture to return to or maintain its original gross shape (this is related to elasticity, plasticity, and diameter)

  • Nonabsorbable - Surgical suture material that is relatively unaffected by the biologic activities of the body tissues and is therefore permanent unless removed

  • Plasticity - Measure of the ability to deform without breaking and to maintain a new form after relief of the deforming force

  • Pliability - Ease of handling of suture material; ability to adjust knot tension and to secure knots (this is related to suture material, filament type, and diameter)

  • Straight-pull tensile strength - Linear breaking strength of suture material

  • Suture pullout value - Application of force to a loop of suture located where tissue failure occurs, which measures the strength of a particular tissue; this varies according to anatomic site and histologic composition (fat, 0.2 kg; muscle, 1.27 kg; skin, 1.82 kg; fascia, 3.77 kg)

  • Tensile strength - Measure of the ability of a material or tissue to resist deformation and breakage

  • Wound breaking strength - Limit of tensile strength of a healing wound at which separation of the wound edges occurs

Suture size refers to the diameter of the suture strand and is denoted by means of zeroes. The more zeroes characterizing a suture size, the smaller the resultant strand diameter (eg, 4-0 or 0000 is larger than 5-0 or 00000). The smaller the suture, the less the tensile strength of the strand.

Suture classification

Sutures may be classified in terms of their origin, their structure, and their absorbability.

Natural vs synthetic

Natural sutures can be made of collagen from mammal intestines or from synthetic collagen (polymers). Tissue reaction and suture antigenicity lead to inflammatory reactions, especially with natural materials.[26, 27] Synthetic sutures are made of artificial polymers.

Monofilament vs multifilament

Monofilament suture material is made of a single strand; this structure is relatively more resistant to harboring microorganisms. It also exhibits less resistance to passage through tissue than multifilament suture does. However, great care must be taken in handling and tying a monofilament suture, because crushing or crimping of the suture can nick or weaken it and lead to undesirable and premature suture failure.

Multifilament suture material is composed of several filaments twisted or braided together. It generally has greater tensile strength and better pliability and flexibility than monofilament suture material, and it handles and ties well. However, because multifilament materials have increased capillarity, the increased absorption of fluid may facilitate the introduction of pathogens, which increases the risk for wound infection and dehiscence.

Multifilament suture material is less stiff than monofilament suture material, but because the individual filaments of a multifilament suture are braided together, an increased coefficient of friction is created when the suture is passed through tissue. Multifilament sutures are often treated with special coatings to facilitate tissue passage and reduce subsequent tissue damage.

Absorbable vs nonabsorbable

Absorbable sutures provide temporary wound support until the wound heals well enough to withstand normal stress. Absorption occurs by enzymatic degradation in natural materials and by hydrolysis in synthetic materials. Hydrolysis causes less tissue reaction than enzymatic degradation.

The first stage of absorption has a linear rate, lasting for several days to weeks. The second stage is characterized by loss of suture mass and overlaps the first stage. Loss of suture mass occurs as a result of leukocytic cellular responses that remove cellular debris and suture material from the line of tissue approximation. Chemical treatments, such as chromic salts, lengthen the absorption time.

It is important to note that loss of tensile strength and the rate of absorption are separate phenomena. The surgeon must recognize that accelerated absorption may occur in patients with fever, infection, or protein deficiency, and this may lead to an excessively rapid decline in tensile strength. Accelerated absorption may also occur in a body cavity that is moist or filled with fluid or if sutures become wet or moist during handling before implantation.

Nonabsorbable sutures elicit a tissue reaction that results in encapsulation of the suture material by fibroblasts. The United States Pharmacopeia (USP) classification of nonabsorbable sutures is as follows:

  • Class I - Silk or synthetic fibers of monofilament, twisted, or braided construction

  • Class II - Cotton or linen fibers or coated natural or synthetic fibers in which the coating contributes to suture thickness without adding strength

  • Class III - Metal wire of monofilament or multifilament construction

Suture characteristics

Both absorbable and nonabsorbable surgical sutures can be made from either natural or synthetic polymers.

Absorbable natural sutures

Absorbable natural suture materials include the following:

  • Collagen

  • Plain surgical gut

  • Fast-absorbing surgical gut

  • Chromic surgical gut

Collagen sutures are derived from the submucosal layer of ovine small intestine or the serosal layer of the bovine small intestine. This collagenous tissue is treated with an aldehyde solution, which crosslinks and strengthens the suture and makes it more resistant to enzymatic degradation. Suture materials treated in this way are called plain gut.

The tensile strength of plain surgical gut is maintained for 7-10 days after implantation (this varies with individual patient characteristics), and absorption is complete within 70 days. This type of suture is used for (1) repair of rapidly healing tissues that require minimal support and (2) ligation of superficial blood vessels.

Fast-absorbing surgical gut is indicated for epidermal use (it is required only for 5-7 days) and is not recommended for internal use.

Chromic surgical gut is treated with chromium salt, which slows down the absorption rate (reaching complete absorption at 90 days). Tensile strength is maintained for 10-14 days. Tissue reaction is due to the noncollagenous material present in these sutures. In addition, patient factors affect absorption rates and make tensile strength somewhat unpredictable. Salthouse et al demonstrated that the mechanism by which chromic surgical gut reabsorbs is the result of sequential attacks by lysosomal enzymes.[28]

Natural-fiber absorbable sutures have several distinct disadvantages. First, they tend to fray during knot construction. Second, there is considerably more variability in their retention of tensile strength than is found with the synthetic absorbable sutures. A search for a synthetic substitute for collagen sutures began in the 1960s. Soon, procedures were perfected for the synthesis of high-molecular-weight polyglycolic acid, which led to the development of the polyglycolic acid sutures.[28]

Absorbable synthetic sutures

Absorbable synthetic sutures are composed of chemical polymers that are absorbed by hydrolysis and cause a lesser degree of tissue reaction after placement. Depending on the anatomic site, surgeon’s preference, and the required suture characteristics, the following types of synthetic absorbable suture may be considered including (but not limited to) the following:

  • Polyglactin 910 (Vicryl)

  • Polycaprolate (Dexon II)

  • Poliglecaprone 25 (Monocryl)

  • Polysorb

  • Polydioxanone (PDS II)

  • Polytrimethylene carbonate (Maxon)

  • V-Loc

  • Polyglytone 621 (Caprosyn)

Polyglactin 910 suture is a braided multifilament suture coated with a copolymer of lactide and glycolide (polyglactin 370). The water-repelling quality of lactide slows loss of tensile strength, and the bulkiness of lactide leads to rapid absorption of suture mass once tensile strength is lost. The suture is also coated with calcium stearate, which permits easy tissue passage, precise knot placement, and smooth tiedown.

The tensile strength pf polyglactin 910 suture is approximately 65% at day 14 after implantation. Absorption is minimal for 40 days and complete in 56-70 days. These sutures cause only minimal tissue reaction. These sutures are used in general soft-tissue approximation and vessel ligation.

A similar suture material is made from polyglycolic acid and coated with polycaprolate (Dexon II). This material is comparable to polyglactin 910 with respect to tensile strength and absorption profile.

Poliglecaprone 25 suture is a monofilament suture that is a copolymer of glycolide and ε-caprolactone. The suture has superior pliability, leading to ease in handling and tying. Tensile strength is high initially, 50-60% at day 7 after implantation, and is lost at day 21. Absorption is complete at 91-119 days. Poliglecaprone 25 sutures are used for subcuticular closure and soft-tissue approximations and ligations. A recent study by Regan et al reported that poliglecaprone 25 sutures caused significantly less suture extrusion than polyglactin 910.[29]

Polysorb is a braided absorbable suture produced from a Lactomer copolymer formed via synthesis of copolymers of glycolide and lactide (in a ratio of 9 to 1). The glycolide and lactide behave differently when exposed to tissue hydrolysis. Glycolide provides for high initial tensile strength but hydrolyzes rapidly in tissue.[20] Lactide has a slower and controlled rate of hydrolysis, or tensile strength loss, and provides for prolonged tensile strength in tissue.

To decrease their friction coefficient, the surfaces of Polysorb sutures are coated with an absorbable mixture of caprolactone-glycolide copolymer and calcium stearyl lactylate.[30] At day 14 after implantation, nearly 80% of the USP tensile strength of these braided sutures remains. Approximately 30% of their USP tensile strength is retained at day 21. Absorption is essentially complete between days 56 and 70.

Polydioxanone, a polyester monofilament suture, provides extended wound support and elicits only a slight tissue reaction. Tensile strength is 70% at day 14 and 25% at day 42. Wound support remains for up to 6 weeks. Absorption is minimal for the first 90 days and essentially complete within 6 months. Like other monofilament sutures, polydioxanone has a low affinity for microorganisms. It is used for soft-tissue approximation, especially in pediatric, cardiovascular, gynecologic, ophthalmic, plastic, and digestive (colonic) situations.

Polytrimethylene carbonate is similar to polydioxanone with regard to tensile strength and absorption profile.

V-Loc is a barbed suture manufactured from 0 polydioxanone that is self-anchoring, with no knots required for wound closure. The elimination of knot tying may reduce many of the challenges of knot construction. This suture consists of axially barbed segments on each side of a midpoint, at which the barbs change direction. The tensile strength of the barbed suture decreases over time. Each suture is attached to a premium cutting and taper-point needle with NuCoat coating technology.[31]

Caprosyn is rapidly absorbing and represents the most recent innovation in the development of monofilament absorbable synthetic sutures. Caprosyn sutures are prepared from polyglytone 621, which is composed of glycolide, caprolactone, trimethylene carbonate, and lactide. Implantation studies in animals indicate that Caprosyn suture retains a minimum of 50-60% USP knot strength at day 5 after implantation and a minimum of 20-30% of knot strength at day 10 days. All of its tensile strength is essentially lost by day 21.

Nonabsorbable natural sutures

Natural nonabsorbable sutures include the following:

  • Surgical silk

  • Surgical cotton

  • Surgical steel

Surgical silk is made of raw silk spun by silkworms. It may be coated with beeswax or silicone. Many surgeons consider silk suture the standard of performance because of its superior handling characteristics. Although classified as nonabsorbable, silk is absorbed by proteolysis and is often undetectable in the wound site by 2 years. Tensile strength decreases with moisture absorption and is lost by 1 year. The main problem with silk suture is the acute inflammatory reaction it triggers. Host reaction leads to encapsulation by fibrous connective tissue.

Surgical cotton is made of twisted, long, staple cotton fibers. Tensile strength is 50% within 6 months and 30-40% by 2 years. Surgical cotton is nonabsorbable and becomes encapsulated within body tissues.

Surgical steel suture is made of stainless steel (iron-chromium-nickel-molybdenum alloy) as a monofilament or a twisted multifilament. This suture can be made with flexibility, fine size, and the absence of toxic elements. Surgical steel demonstrates high tensile strength with little loss over time and low tissue reactivity. The material also holds knots well.

Surgical steel suture is used primarily in orthopedic, neurosurgical, and thoracic applications. This type of suture may also be used in abdominal wall closure, sternum closure, and retention. However, it can be difficult to handle because of kinking, fragmentation, and barbing, which render the wire useless and may present a risk to the surgeon’s safety.[32]

The cutting, tearing, or pulling of other patient tissues is also a risk. In addition, surgical steel in the presence of other metals or alloys may cause electrolytic reactions; therefore, it is not a safe choice in these circumstances. The size of a steel suture is classified according to the Brown and Sharpe gauge –that is, from 18 gauge (largest diameter) to 40 gauge (smallest diameter). The standard USP classification is also used to denote wire diameter.

Nonabsorbable synthetic sutures

Nonabsorbable synthetic sutures include the following:

  • Nylon (Ethilon/Monosof [monofilament] and Nurolon/Surgilon [braided])

  • Polyester fiber (Mersilene/Surgidac [uncoated] and Ethibond/Ti-cron [coated])

  • Polybutester (Novafil)

  • Coated polybutester (Vascufil)

  • Polypropylene (Prolene)

  • Surgipro II

Nylon is a polyamide polymer suture material available in monofilament and braided forms. Its elasticity makes it useful in retention and skin closure. Nylon is quite pliable, especially when moist. (A premoistened form is available for cosmetic plastic surgery.) The braided forms are coated with silicone. Nylon suture has good handling characteristics, though its memory tends to return the material to its original straight form.

Nylon has 81% tensile strength at 1 year after implantation, 72% at 2 years, and 66% at 11 years. It is stronger than silk and, unlike silk, elicits only a minimal acute inflammatory reaction. Nylon is hydrolyzed slowly, but the remaining suture material is stable at 2 years, as a consequence of gradual encapsulation by fibrous connective tissue.

Polyester fiber (Mersilene/Surgidac [uncoated] and Ethibond/Ti-cron [coated]) suture material, formed from a polymer of polyethylene terephthalate, is available either uncoated or coated with polybutilate or silicone. The coating reduces friction for ease of tissue passage and improved suture pliability and tiedown.

Polyester fiber sutures elicit minimal tissue reaction and last indefinitely in the body. they are stronger than natural-fiber sutures and do not weaken with moistening. The material provides precise, consistent suture tension and retains tensile strength. This suture is commonly used for vessel anastomosis and the placement of prosthetic materials.

Polybutester suture, composed of a block copolymer containing butylene terephthalate and polytetramethylene ether glycol, is a monofilament suture with unique performance characteristics that may be advantageous for wound closure.[33] With a polybutester suture, low forces yield significantly greater elongation than is seen in the other sutures. In addition, the elasticity of polybutester suture is superior to that of the other sutures, allowing the suture to return to its original length once the load is removed.

Coated polybutester suture is a unique absorbable polymer that enhances the clinical performance of polybutester suture by virtue of its coating, a polytribolate polymer composed of glycolide, ε-caprolactone, and poloxamer 188.[34] Coating the polybutester suture markedly reduces its drag force in musculoaponeurotic, colonic, and vascular tissue.

Polypropylene is a monofilament suture that is an isostatic crystalline stereoisomer of a linear propylene polymer, permitting little or no saturation. It does not adhere to tissues and is useful as a pullout suture (eg, in subcuticular closure). It also holds knots better than other monofilament synthetic materials do.

Polypropylene is biologically inert and elicits minimal tissue reaction. It is not subject to degradation or weakening and maintains tensile strength for up to 2 years. This material is useful in contaminated and infected wounds, minimizing later sinus formation and suture extrusion. Interestingly, a recent study compared poliglecaprone 25 with polypropylene for superficial closures and did not find a statistically significant difference in cosmetic results.[35]

Surgipro II is a polypropylene suture that was developed to have increased resistance to fraying during knot rundown, especially with smaller-diameter sutures. This material is extremely inert in tissue and has been found to retain tensile strength in tissues for as long as 2 years. Surgipro II is widely used in plastic, cardiovascular, general, and orthopedic surgery. It exhibits a lower drag coefficient in tissue than nylon does, making it ideal for use in continuous suture closure.[25]

Needle qualities

The ideal surgical needle would have the following characteristics:

  • It is made of high-quality stainless steel

  • It has the smallest diameter possible

  • It is stable in the grasp of the needle holder

  • It is capable of implanting suture material through tissue with minimal trauma

  • It is sharp enough to penetrate tissue with minimal resistance

  • It is sterile and corrosion-resistant to prevent introduction of microorganisms or foreign materials into the wound

The following terms are employed to describe various characteristics related to needle performance:

  • Strength - Resistance to deformation during repeated passes through tissue (ie, increased needle strength results in decreased tissue trauma); ultimate moment is the measure of maximum strength determined by bending the needle to 90°, and surgical-yield moment is the amount of angular deformation that can occur before permanent needle deformation results

  • Ductility - Resistance (of a needle) to breakage under a given amount of deformation or bending

  • Sharpness - Measure of the ability of the needle to penetrate tissue; factors affecting sharpness include the angle of the point and the taper ratio (ie, ratio of taper length to needle diameter)

  • Clamping moment - Stability of a needle in a needle holder, determined by measuring the interaction of the needle body with the jaws of the needle holder

Needle construction

A surgical needle has three sections: the point, the body, and the swage (see the image below). The point is the sharpest portion and is used to penetrate the tissue. The body represents the midportion of the needle. The swage is the thickest portion of the needle and the portion to which the suture material is attached.

Diagram of a needle. Diagram of a needle.

Point

The point portion of the needle extends from the tip to the maximum cross-section of the body. Point types include the following (see the image below):

  • Cutting needles (conventional, reverse, or side [spatula])

  • Taper-point (round) needles

  • Beveled conventional cutting edge needles

  • Blunt-point needles

    Commonly used suture needles, with cross-sections Commonly used suture needles, with cross-sections of needles shown at point, body, and swage. (A) Taper-point needle. (B) Conventional cutting needle. (C) Reverse cutting needle.

A cutting needle has at least two opposing cutting edges (the point is usually triangular). This type is designed to penetrate dense, irregular, and relatively thick tissues. The point cuts a pathway through tissue and is ideal for skin sutures. Sharpness is due to the cutting edges.

Conventional cutting needles have three cutting edges (a triangular cross-section that changes to a flattened body). The third cutting edge is on the inner, concave curvature (surface-seeking).

In reverse-cutting needles, the third cutting edge is on the outer convex curvature of the needle (depth-seeking). These needles are stronger than conventional cutting needles and have a reduced risk of cutting out tissue. They are designed for tissue that is tough to penetrate (eg, skin, tendon sheaths, or oral mucosa). Reverse-cutting needles are also beneficial in cosmetic and ophthalmic surgery, causing minimal trauma.

Side-cutting (spatula) needles are flat on the top and bottom surfaces to reduce tissue injury. These needles allow maximum ease of penetration and control as they pass between and through tissue layers. Side-cutting needles were designed initially for ophthalmic procedures.

Taper-point (round) needles penetrate and pass through tissues by stretching without cutting. A sharp tip at the point flattens to an oval or rectangular shape. The sharpness is determined by the taper ratio (8-12:1) and the tip angle (20-35°). The needle is sharper if it has a higher taper ratio and a lower tip angle. The taper-point needle is used for easily penetrated tissues (eg, subcutaneous layers, dura, peritoneum, and abdominal viscera) and minimizes the potential tearing of fascia.

A beveled conventional cutting needle was developed with performance characteristics superior to those of other conventional cutting needles. It is composed of a unique stainless steel, ASTM 45500, that is heat-treated after the curving process to enhance its resistance to bending. The angle of presentation of the cutting edge is decreased to enhance sharpness. On the basis of the results of experimental and clinical studies done by Kaulbach et al, this beveled conventional cutting needle is recommended for closure of lacerations.[36]

Blunt point needles dissect friable tissue rather than cut it. The points are rounded and blunt, ideal for suturing the liver and kidneys. Additionally, blunt needles are being developed for more conventional uses in an effort to reduce needlestick injuries.

Body

Needle body types include the following:

  • Straight body

  • Half-curved ski body

  • Curved body

  • Compound curved body

The body part of the needle incorporates most of the needle length and is important for interaction with the needle holder and the ability to transmit the penetrating force to the point. Needle factors that affect this interaction include needle diameter and radius, body geometry, and stainless steel alloy. These components determine the needle-bending moment, the ultimate moment, the surgical-yield moment, and needle ductility.

The straight-body needle is used to suture easily accessible tissue that can be manipulated directly by hand. It is also used in microsurgery for nerve and vessel repair. Examples of straight-body needles include the Keith needle, which is used for skin closure of abdominal wounds, and the Bunnell needle, which is used for tendon and gastrointestinal (GI) tract repair.

The half-curved ski needle is rarely used in skin closure, because of its handling characteristics. The straight portion of the body does not follow the curved point, resulting in an enlarged curved point that makes the needle difficult to handle.

The curved needle has a predictable path through tissue and requires less space for maneuvering than a straight needle does. The semicircular path is the optimal course for sutures through tissue and provides an even distribution of tension. Body curvature commonly follows a 0.25-in., 0.375-in., 0.5-in., or 0.625-in. circle. The 0.375-in. circle is used most commonly for skin closure; the 0.5-in. circle was designed for confined spaces, and more manipulation (ie, increased wrist motion) by the surgeon is required.

The compound curved needle was originally designed for anterior-segment ophthalmic surgery. The body has a tight 80° curvature at the tip, which becomes a 45° curvature throughout the remainder of the body. A microvascular compound curved needle may also facilitate vessel approximation in microvascular surgery.

Swage

The suture attachment end creates a single, continuous unit of suture and needle, known as the swage. The swage may be designed to permit easy release of the needle and suture material (popoff) and includes the following types:

  • Channel swage

  • Drill swage

  • Nonswaged

In a channel swage, a needle is created with a channel into which the suture is introduced, and the channel is crimped over the suture to secure it into place. The diameter of the channel swage is greater than the diameter of the needle body.

In a drill swage, material is removed from the needle end (sometimes with a laser), and the needle is crimped over the suture. The diameter of the drill swage is less than the diameter of the needle body.

Alternatively, in a nonswaged needle, the suture may be passed through an eye, similar to that found in a sewing needle. In a closed-eye configuration, the shape may be round, oblong, or square. In a French (split or spring) eye, a slit is made in the end of the needle with ridges that catch and hold the suture in place.

Several disadvantages are associated with the use of a nonswaged needle. Passage of a double strand of suture through tissue leads to more tissue trauma. The suture is more likely to become unthreaded prematurely than it would be with a swaged needle. Moreover, decreased handling helps maintain suture integrity. Swaged sutures are not subject to suture fraying or damage caused by sharp corners in the eye of eyed needles.

Coating

The needle may be coated with silicone to permit easier tissue passage. The coating helps reduce the force needed to make initial tissue penetration and decrease the frictional forces as the body of the needle passes through the tissue.

Measurements

The chord length, or bite width, is the linear distance from the point of the curved needle to the swage (see the image below); the needle length is the distance measured along the needle from the point to the swage. The needle length, not the chord length, is the measurement supplied on suture packages. The radius, or bite depth, is the distance from the body of the needle to the center of the circle along which the needle curves; the diameter is considered the gauge or thickness of the needle wire.

Anatomy of needle. Anatomy of needle.

Needle–needle holder interaction

The stability of the needle within the needle holder affects needle control and performance. The jaws of the needle holder must be appropriate to the needle size to hold it securely and prevent rocking, turning, and twisting (see the image below). An ovoid cross-section of the needle body often maximizes both the surface contact with the needle-holder jaws and the bending moment of the needle.

Interaction between needle holder and suture needl Interaction between needle holder and suture needle. (A) Needle holder of appropriate size for needle. (B) Needle holder that is too large for needle—pressure applied by needle holder leads to inadvertent straightening of suture needle. (C) Needle holder that is too small for needle—needle rotates around long axis of needle holder.

The needle-holder handle must be appropriate for the required depth of suture placement. The difference between the length of the handle and the jaw creates a mechanical advantage for exerting force through the needle point.

The needle-holder clamping moment is the force applied to a suture needle by a needle holder. The jaws of the needle holder contact a curved needle at one point on the outer curvature and at two points along the inner curvature. The force against the needle creates a moment arm, which acts to flatten the curvature of the needle.

Technically speaking, the needle-holder clamping moment must be less than the surgical yield of the needle, or the needle will bend and ultimately may break. A bent needle takes a relatively traumatic path through soft tissue and may cause increased soft-tissue injury. Repetitive injury by the needle holder also may cause the needle to break. If the broken portion of the needle is not identified and retrieved immediately, surgery may be delayed in an effort to find it. The need for intraoperative radiology and other potential difficulties may ensue.

Studies by Abidin et al demonstrated that the sharp edges of smooth needle-holder jaws cut the smooth surface of monofilament sutures, weakening their strength.[37] When the smooth tungsten carbide inserts of needle holders clamped 6-0 monofilament nylon suture with the first opposing teeth of the needle holder ratchet mechanism interlock, there was a significant reduction in suture breaking strength.

This damage to the suture can be prevented by mechanically grinding the outer edges of the smooth tungsten carbide inserts so as to achieve a rounded edge. When this was done, clamping the suture with the smooth jaws of the needle holder was atraumatic, with no demonstrable damage to the suture’s breaking strength.[37]

Monitoring and Follow-up

Suture removal

Sutures should be removed within 1-2 weeks of their placement, depending on the anatomic location. Prompt removal reduces the risk of suture marks, infection, and tissue reaction. The average wound usually achieves approximately 8% of its expected tensile strength 1-2 weeks after surgery. To prevent dehiscence and spread of the scar, sutures should not be removed too soon.

In general, the greater the tension across a wound, the longer the sutures should remain in place. As a guide, on the face, sutures should be removed in 5-7 days; on the neck, 7 days; on the scalp, 10 days; on the trunk and upper extremities, 10-14 days; and on the lower extremities, 14-21 days. Sutures in wounds under greater tension may have to be left in place slightly longer. Buried sutures, which are placed with absorbable suture material, are left in place because they dissolve.

Proper suture removal technique is essential for maintaining good results after sutures are properly selected and executed. Sutures are gently elevated with forceps, and one side of the suture is cut. The suture is then gently grasped by the knot and gently pulled toward the wound or suture line until the suture material is completely removed. If the suture is pulled away from the suture line, the wound edges may separate. Steri-Strips may be applied with a tissue adhesive to provide continued supplemental wound support after the sutures are removed.

 

Technique

General Principles

Many varieties of suture material and needles are available. The choice of sutures and needles is determined by the location of the lesion, the thickness of the skin in that location, and the amount of tension exerted on the wound. Regardless of the specific suture and needle chosen, the basic techniques of needle holding, needle driving, and knot placement remain the same.

Suture placement

A needle holder is used to grasp the needle at the distal portion of the body, one half to three quarters of the distance from the tip of the needle, depending on the surgeon’s preference. The needle holder is tightened by squeezing it until the first ratchet catches. The needle holder should not be tightened excessively, because damage to both the needle and the needle holder may result. The needle is held vertically and longitudinally perpendicular to the needle holder (see the image below).

Needle is placed vertically and longitudinally per Needle is placed vertically and longitudinally perpendicular to needle holder.

Incorrect placement of the needle in the needle holder may result in a bent needle, difficult penetration of the skin, or an undesirable angle of entry into the tissue. The needle holder is held by placing the thumb and the fourth finger into the loops and placing the index finger on the fulcrum of the needle holder to provide stability (see the first image below). Alternatively, the needle holder may be held in the palm to increase dexterity (see the second image below).

Needle holder is held through loops between thumb Needle holder is held through loops between thumb and fourth finger, and index finger rests on fulcrum of instrument.
Needle holder is held in palm, allowing greater de Needle holder is held in palm, allowing greater dexterity.

The tissue must be stabilized to allow suture placement. Depending on the surgeon’s preference, toothed or untoothed forceps or skin hooks may be used to grasp the tissue gently. Excessive trauma to the tissue being sutured should be avoided to reduce the possibility of tissue strangulation and necrosis.

Forceps are necessary for grasping the needle as it exits the tissue after a pass. Before removal of the needle holder, grasping and stabilizing the needle is important. This maneuver decreases the risk of losing the needle in the dermis or subcutaneous fat, and it is especially important if small needles are used in areas such as the back, where large needle bites are necessary for proper tissue approximation.

The needle should always penetrate the skin at a 90° angle, which minimizes the size of the entry wound and promotes eversion of the skin edges. The needle should be inserted 1-3 mm from the wound edge, depending on skin thickness. The depth and angle of the suture depends on the particular suturing technique. In general, the two sides of the suture should become mirror images, and the needle should also exit the skin perpendicular to the skin surface.

Knot tying

Once the suture is satisfactorily placed, it must be secured with a knot.[38] The instrument tie is used most commonly in cutaneous surgery. The square knot is traditionally used.

First, the tip of the needle holder is rotated clockwise around the long end of the suture for two complete turns (see the image below). The tip of the needle holder is used to grasp the short end of the suture. The short end of the suture is pulled through the loops of the long end by crossing the hands, so that the two ends of the suture are on opposite sides of the suture line. The needle holder is rotated counterclockwise once around the long end of the suture. The short end is then grasped with the needle holder tip and pulled through the loop again.

Knot tying. Knot tying.

The suture should be tightened sufficiently to approximate the wound edges without constricting the tissue. Sometimes, leaving a small loop of suture after the second throw is helpful. This reserve loop allows the stitch to expand slightly and is helpful in preventing the strangulation of tissue because the tension exerted on the suture increases with increased wound edema. Depending on the surgeon’s preference, one or two additional throws may be added.

Properly squaring successive ties is important. In other words, each tie must be laid down perfectly parallel to the previous tie. This procedure is important in preventing the creation of a granny knot, which tends to slip and is inherently weaker than a properly squared knot. When the desired number of throws is completed, the suture material may be cut (if interrupted stitches are used), or the next suture may be placed.

Placement of Specific Suture Types

Simple interrupted suture

The most commonly used and most versatile suture in cutaneous surgery is the simple interrupted suture.[39] This suture is placed by inserting the needle perpendicular to the epidermis, traversing the epidermis and the full thickness of the dermis, and exiting perpendicular to the epidermis on the opposite side of the wound. The two sides of the stitch should be symmetrically placed in terms of depth and width.

In general, the suture should have a flask-shaped configuration, that is, the stitch should be wider at its base (dermal side) than at its superficial portion (epidermal side). If the stitch encompasses a greater volume of tissue at the base than at its apex, the resulting compression at the base forces the tissue upward and promotes eversion of the wound edges (see the image below). This maneuver decreases the likelihood of creating a depressed scar as the wound retracts during healing.

Simple interrupted suture placement. Bottom right Simple interrupted suture placement. Bottom right image shows a flask-shaped stitch, which maximizes eversion.

As a rule, tissue bites should be evenly placed so that the wound edges meet at the same level; this minimizes the possibility of mismatched wound-edge heights (ie, stepping). However, the size of the bite taken from the two sides of the wound can be deliberately varied by modifying the distance of the needle insertion site from the wound edge, the distance of the needle exit site from the wound edge, and the depth of the bite taken.

The use of differently sized needle bites on each side of the wound can correct preexisting asymmetry in edge thickness or height. Small bites can be used to precisely coapt wound edges. Large bites can be used to reduce wound tension. Proper tension is important to ensure precise wound approximation while preventing tissue strangulation. (See the image below.)

Line of interrupted sutures. Line of interrupted sutures.

Simple running suture

A simple running (continuous) suture is essentially an uninterrupted series of simple interrupted sutures. The suture is started by placing a simple interrupted stitch, which is tied but not cut. A series of simple sutures are placed in succession, without the suture material being tied or cut after each pass. The sutures should be evenly spaced, and tension should be evenly distributed along the suture line.

The line of stitches is completed by tying a knot after the last pass at the end of the suture line. The knot is tied between the tail end of the suture material where it exits the wound and the loop of the last suture placed. (See the image below.)

Running suture line. Running suture line.

Running locked suture

A simple running suture may be either locked or left unlocked. The first knot of a running locked suture is tied as in a traditional running suture and may be locked by passing the needle through the loop preceding it as each stitch is placed (see the image below). This suture is also known as the baseball stitch because of the final appearance of the running locked suture line.

Running locked suture. Running locked suture.

Vertical mattress suture

A vertical mattress suture is a variation of a simple interrupted suture. It consists of a simple interrupted stitch placed wide and deep into the wound edge and a second more superficial interrupted stitch placed closer to the wound edge and in the opposite direction (see the image below). The width of the stitch should be increased in proportion to the amount of tension on the wound—that is, the higher the tension, the wider the stitch.

Vertical mattress suture. Vertical mattress suture.

Half-buried vertical mattress suture

A half-buried vertical mattress suture is a modification of a vertical mattress suture that eliminates two of the four entry points, thereby reducing scarring. It is placed in the same manner as the vertical mattress suture, except that the needle penetrates the skin to the level of the deep part of the dermis on one side of the wound, takes a bite in the deep part of the dermis on the opposite side without exiting the skin, crosses back to the original side, and finally exits the skin. Entry and exit points thus are kept on one side of the wound.

Pulley suture

A pulley suture is a modification of a vertical mattress suture. A vertical mattress suture is placed, the knot is left untied, and the suture is looped through the external loop on the other side of the incision and pulled across (see the image below). At this point, the knot is tied. This new loop functions as a pulley, directing tension away from the other strands.

Pulley stitch, type 1. Pulley stitch, type 1.

Far-near near-far modified vertical mattress sutures

Another stitch that serves the same function as a pulley suture is a far-near near-far modified vertical mattress suture. The first loop is placed about 4-6 mm from the wound edge on the far side and about 2 mm from the wound edge on the near side. The suture crosses the suture line and reenters the skin on the original side at 2 mm from the wound edge on the near side. The loop is completed, and the suture exits the skin on the opposite side 4-6 mm away from the wound edge on the far side (see the image below). A pulley effect is thus created.

Far-near near-far modification of vertical mattres Far-near near-far modification of vertical mattress suture, creating pulley effect.

Horizontal mattress suture

A horizontal mattress suture is placed by entering the skin 5 mm to 1 cm from the wound edge. The suture is passed deep in the dermis to the opposite side of the suture line and exits the skin equidistant from the wound edge (in effect, a deep simple interrupted stitch). The needle reenters the skin on the same side of the suture line 5 mm to 1 cm lateral of the exit point. The stitch is passed deep to the opposite side of the wound, where it exits the skin; the knot is then tied (see the image below).

Horizontal mattress suture. Horizontal mattress suture.

Half-buried horizontal suture

A half-buried horizontal suture (also referred to as a tip stitch or three-point corner stitch) begins on the side of the wound on which the flap is to be attached. The suture is passed through the dermis of the wound edge to the dermis of the flap tip. The needle is passed laterally in the same dermal plane of the flap tip, exits the flap tip, and reenters the skin to which the flap is to be attached. The needle is directed perpendicularly and exits the skin; the knot is then tied (see the image below).

Half-buried horizontal suture (tip stitch, three-p Half-buried horizontal suture (tip stitch, three-point corner stitch).

Dermal-subdermal sutures

A dermal-subdermal suture is placed by inserting the needle parallel to the epidermis at the junction of the dermis and the subcutis. The needle curves upward and exits in the papillary dermis, again parallel to the epidermis. The needle is inserted parallel to the epidermis in the papillary dermis on the opposing edge of the wound, curves down through the reticular dermis, and exits at the base of the wound at the interface between the dermis and the subcutis and parallel to the epidermis.

The knot is tied at the base of the wound to minimize the possibility of tissue reaction and extrusion of the knot. If the suture is placed more superficially in the dermis at 2-4 mm from the wound edge, eversion is increased.

Buried horizontal mattress suture

A buried horizontal mattress suture is a purse-string suture. The suture must be placed in the mid-to-deep part of the dermis to prevent the skin from tearing. If tied too tightly, the suture may strangulate the approximated tissue.

Running horizontal mattress sutures

A simple suture is placed, and the knot is tied but not cut. A continuous series of horizontal mattress sutures is placed, with the final loop tied to the free end of the suture material.[40]

Running subcuticular sutures

A running subcuticular suture is a buried form of a running horizontal mattress suture. It is placed by taking horizontal bites through the papillary dermis on alternating sides of the wound (see the image below). No suture marks are visible, and the suture may be left in place for several weeks.

Subcuticular stitch. Skin surface remains intact a Subcuticular stitch. Skin surface remains intact along length of suture line.

Running subcutaneous suture

A running subcutaneous suture begins with a simple interrupted subcutaneous suture, which is tied but not cut. The suture is looped through the subcutaneous tissue by successively passing through the opposite sides of the wound. The knot is tied at the opposite end of the wound by knotting the long end of the suture material to the loop of the last pass that was placed.

Running subcutaneous corset plication stitch

Before the needle is inserted, forceps are used to pull firmly on at least 1-2 cm of tissue to ensure tissue strength.[16] The corset plication includes at least 1-2 cm of adipose tissue and fascia within each bite. After the first bite is tied, bites are taken on opposite sides of the wound in a running fashion along the defect. The free end is pulled firmly to reduce the size of the defect, and the suture is then tied.

Variations of tip (corner) sutures

Modified half-buried horizontal mattress suture

In a modified half-buried horizontal mattress suture, an additional vertical mattress suture is placed superficial to the half-buried horizontal mattress suture. A small skin hook instead of forceps is used to avoid trauma of the flap.[6]

Deep tip stitch

A deep tip stitch is essentially a fully buried form of a three-corner stitch. The suture is placed into the deep dermis of the wound edge to which the flap is to be attached, passed through the dermis of the flap tip, and inserted into the deep dermis of the opposite wound edge.[5]

Alternative Methods of Wound Closure

Wound closure tapes

Wound closure tapes (eg, Steri-Strips) are composed of strips of reinforced microporous surgical adhesive tape. They are used to provide extra support to a suture line, either when running subcuticular sutures are used or after sutures are removed.

Wound closure tapes may reduce spreading of the scar if they are kept in place for several weeks after suture removal. Often, they are used in conjunction with a tissue adhesive. Because they have a tendency to fall off, they are used mainly in low-tension wounds and rarely for primary wound closure.

Staples

Stainless steel staples are frequently used in wounds under high tension, including wounds on the scalp or the trunk. Advantages of staples include quick placement, minimal tissue reaction, low risk of infection, and strong wound closure. Disadvantages include less precise wound edge alignment and higher cost.

Tissue adhesive

Superglues that contain acrylates may be applied to superficial wounds to block pinpoint skin hemorrhages and to precisely coapt wound edges. Because of their bacteriostatic effects and easy application, they have gained increasing popularity.[41, 42, 43, 44]

Tissue adhesives have demonstrated either cosmetic equivalence or superiority to traditional sutures in various procedures, including sutureless closure of pediatric day surgeries, saphenous vein harvesting for coronary artery bypass, and blepharoplasty.[45, 46, 47] The most commonly used adhesive, 2-octyl cyanoacrylate (Dermabond), has also been used as a skin bolster for suturing thin, atrophic skin.[48]

Advantages of these topical adhesives include rapid wound closure, painless application, reduced risk of needle sticks, absence of suture marks, and elimination of any need for removal. Disadvantages include increased cost and less tensile strength (in comparison with sutures).

The use of tissue adhesives in dermatologic surgery is still evolving. It appears that using high viscosity 2-octyl cyanoacrylate in the repair of linear wounds after Mohs micrographic surgery results in cosmetic outcomes equivalent to those reported with the use of epidermal sutures.[49]

Greenhill and O’Regan reported on the use of N-butyl 2-cyanoacrylate for closure of parotid wounds and its relation to keloid and hypertrophic scar formation, as compared with the use of sutures.[50] Their results indicated a simpler technique and a comparable result with the tissue adhesive.

In a related area, Tsui and Gogolewski reported on the use of microporous biodegradable polyurethane membranes, which may be useful for coverage of skin wounds, among other things.[51]

Barbed sutures

A barbed suture has been developed that is being evaluated for its efficacy in cutaneous surgery. The proposed advantage of such a suture is the avoidance of suture knots. Suture knots theoretically may be a nidus for infection, are tedious to place, may place ischemic demands on tissue, and may extrude following surgery.

A randomized controlled trial comparing a barbed suture with conventional closure using 3-0 polydioxanone suture suggests that a barbed suture has a safety and cosmesis profile similar to that of a conventional suture when used to close cesarean delivery wounds.[52]

Barbed sutures have also been used in minimally invasive procedures to lift ptotic face and neck tissue. In one study, average patient satisfaction 11.5 months after a thread lift was 6.9/10.[53] By 3 months after the procedure, the skin of the neck and jawline relaxed and the final results became apparent. Overall, the barbed suture lift was determined to provide sustained improvement in facial laxity.

These positive findings notwithstanding, painful dysesthesias and suture migration distant to the insertion site have been reported.[54, 55] Although the long-term efficacy of barbed suspension sutures remains unclear, they may allow a minimally invasive facial lift with few adverse effects.[56]

Novel punch biopsy closure

Placing sutures lateral to a punch biopsy causes the defect to taper, allowing a more linear closure and yielding improved cosmetic outcomes.[57] A simple interrupted stitch is placed 1-3 mm lateral to a wound edge, a second stitch is placed 1-3 mm lateral to the opposite wound edge, and a final stitch is placed at the center of the wound. Sites larger than 4 mm may require additional interrupted stitches. Disadvantages include extended procedure time and increased risk of suture marks.

 

Questions & Answers

Overview

What are the primary goals of suturing?

What is the basis for selection of suture technique?

How are the cosmetic and functional results of suturing optimized?

What are advantages and disadvantages of a simple interrupted suture technique?

What are advantages and disadvantages of a simple running suture technique?

What are indications for the running locked suture technique?

What are the advantages and disadvantages of a vertical mattress suture technique?

What are indications for the half-buried vertical mattress suture technique?

What are indications for the pulley suture technique?

What are indications for the far-near near-far modified vertical mattress suture technique?

What are the advantages and disadvantages of a horizontal mattress suture technique?

What are the advantages and disadvantages of half-buried horizontal suture technique?

What are indications for the absorbable buried suture technique?

What are indications for the dermal-subdermal suture technique?

What are indications for the buried horizontal mattress suture technique?

What are indications for the running horizontal mattress suture technique?

What are indications for the running subcuticular suture technique?

What are the advantages and disadvantages of a running subcutaneous suture technique?

What are indications for the running subcutaneous corset plication stitch technique?

What are indications for the modified half-buried horizontal mattress suture technique?

What are indications for the deep tip stitch suture technique?

What does effective suturing technique depend on?

What are the principles of suturing technique selection?

What is the role of Biogel Puncture Indication System during suturing?

What is the basis for needle selection for suturing?

What is the basis for needle-holder selection for suturing?

What are the advantages of Polysorb sutures compare to polyglactin 910 (Vicryl) sutures?

What are the benefits of polytrimethylene carbonate (Maxon) sutures?

What are the indications for barbed suture (V-Loc)?

What are the benefits of polyglytone 621 (Caprosyn) sutures compare to chromic gut sutures?

Periprocedural Care

What equipment is required for wound closure with sutures?

What measures should be taken to minimize the risk of wound infection from sutures?

What are the benefits of stainless steel surgical needles for suturing?

Which factors affect closure and healing of sutured wounds?

What are the ideal characteristics of suture material?

What are the essential characteristics of all suture materials?

Which terms are used to characterize suture material?

How are sutures classified?

What are the differences between natural and synthetic sutures?

What are the differences between monofilament and multifilament sutures?

What are the differences between absorbable and nonabsorbable sutures?

Are absorbable and nonabsorbable sutures natural or synthetic?

What are the advantages of absorbable natural sutures?

What are the types of absorbable synthetic sutures?

What are the indications and contraindications for nonabsorbable natural sutures?

What are indications for nonabsorbable synthetic sutures?

What are the ideal characteristics of surgical needle used in suturing?

What terms are used to describe needle performance in suturing?

What are the sections of a surgical needle used in suturing?

What are the types of needle points and when are they used in suturing?

What are the types of needle bodies and when are they used in suturing?

What are the types of needle swages and when are they used in suturing?

What is the role of silicone in suturing?

How are suture needles measured?

What is the role of the needle-holder in suturing?

When should sutures be removed?

How should sutures be removed?

Technique

What is the basis for suture material and needle selection?

What are the steps in suture placement?

How are knots tied to secure suture placement?

How is the simple interrupted suture placed?

How is the simple running suture placed?

How a running is locked suture placed?

How is the vertical mattress suture placed?

How is the half-buried vertical mattress suture placed?

How is the pulley suture placed?

How is the far-near near-far modified vertical mattress suture placed?

How is the horizontal mattress suture placed?

How is the half-buried horizontal suture placed?

How are dermal-subdermal sutures placed?

How is the buried horizontal mattress suture placed?

How are the running horizontal mattress sutures placed?

How should running subcuticular sutures be placed in reference to suturing techniques?

How is the running subcutaneous suture placed?

How is the modified half-buried horizontal mattress suture placed?

How is the deep tip stitch suture placed?

How is the running subcutaneous corset plication suture placed?

What is the role of wound closure tapes in following suturing?

What are the advantages and disadvantages of the use of staples for wound closure?

What are the advantages of superglues (tissue adhesive) for wound closure?

What is the role of barbed sutures in wound closure?

What is the placement and suturing technique to close a punch biopsy wound?