Version May 2024
INTRODUCTION — The ideal abdominal wound closure provides strength and a barrier to infection. In addition, the closure should be efficient, performed without tension or ischemia, comfortable for the patient, and aesthetic.
Closure of abdominal incisions will be reviewed here. Incisions for opening the abdomen, wound healing, and wound complications are discussed separately. (See "Incisions for open abdominal surgery" and "Complications of abdominal surgical incisions".)
MATERIALS
Sutures — Wounds have less than 5 percent of normal tissue strength during the first postoperative week; thus, wound security is dependent solely upon the suture closure. (See "Skin laceration repair with sutures" and "Skin laceration repair with sutures", section on 'Suture selection'.)
Size — The suture should be the smallest caliber that is strong enough to reapproximate the tissue and keep the wound intact during normal postoperative activity [1]. Suture caliber is one factor in minimizing the amount of foreign material in the wound.
Synthetic versus natural — A critical element of effective closure is the choice of suture material. Sutures can be made from natural fibers or produced synthetically. Natural suture materials include silk, linen, and catgut (dried and treated bovine or ovine intestine). Synthetic sutures are made from a variety of textiles such as nylon or polyester, formulated specifically for surgical use.
Advantages of synthetic suture over natural fibers include:
●Greater uniformity
●Greater tensile strength
●Longer duration of support during wound healing
●Greater wound security
●Less inflammatory response [2,3]
●Less theoretical risk of disease transmission from animals (eg, bovine spongiform encephalopathy)
Absorbable versus nonabsorbable — Synthetic and natural sutures can be either absorbable or nonabsorbable. Each has characteristics that make them appropriate in various circumstances, depending on the circumstance.
Synthetic absorbable sutures are made from polyglycolic acid or other glycolide polymers and are generally degraded within days to weeks, although delayed absorbable suture may retain strength for up to two months (table 1 and table 2). They generally produce less tissue reaction than natural absorbable sutures (eg, plain gut, chromic catgut), which is thought to be due to the nature of suture breakdown. Synthetic absorbable sutures are broken down by hydrolysis, whereas natural absorbable sutures are degraded by proteolysis.
Common types of synthetic absorbable sutures and their in vivo half-lives are listed below [4]:
●Polyglactin 910 (Vicryl) – Two weeks
●Polyglycolic acid (Dexon) – Two weeks
●Poliglecaprone (Monocryl) – Two weeks
●Polydioxanone (PDS) – Three weeks
●Polyglyconate (Maxon) – Six weeks
Nonabsorbable suture typically maintains tensile strength for more than two months, and many synthetics remain in the incision permanently. In theory, nonabsorbable sutures made of natural fibers, such as cotton, linen, and silk, remain permanently in the wound, although, in reality, they gradually disappear.
Synthetic nonabsorbable sutures generate similar tensile strength and tissue reaction as synthetic absorbable sutures, but they have longer wound security (300 days or more). Some examples of this type of suture include polyamide (Nylon), polypropylene (Prolene), polybutester (Novafil), and polyester (Mersilene).
As a result of their increased and prolonged tensile strength, it might be predicted that nonabsorbable sutures should decrease the risk of wound dehiscence and hernia, compared with absorbable sutures. However, the superiority of nonabsorbable sutures has not been consistently found in meta-analyses of randomized trials for midline closure [5-7]. Nonabsorbable sutures are associated with an increased risk of suture sinus and prolonged wound pain compared with synthetic absorbable suture (odds ratio [OR] 2.18, 95% CI 1.48-3.22; OR 2.05, 95% CI 1.52-2.77, respectively) [5]. (See 'Midline' below and 'Knots' below.)
Monofilament versus multifilament — Another important characteristic of suture that determines its behavior is whether it is monofilament or multifilament. Synthetic nonabsorbable monofilament sutures (eg, polyamide and polypropylene) are more resistant to serious infection than are multifilament sutures and natural fibers. Thus, the composition of the suture, as well as the structure, influences the rate of bacterial absorption and proliferation [8]. This was illustrated in the following representative reports:
●In a study designed to determine the risk of infection for different suture materials, synthetic nonabsorbable monofilament sutures of nylon, wire, and polypropylene were associated with less serious infection than multifilament and natural fiber sutures [9]. This was determined by placing sutures in rabbit subcutaneous tissue; the tissue was then inoculated with staphylococcus.
●In another study, both braided silk and braided nylon absorbed similar numbers of bacteria, while monofilament sutures absorbed significantly less. Braided polyglycolic acid absorbed an intermediate number of bacteria [10]. In this guinea pig study, sutures were placed in solutions containing bacteria and then the number of bacteria absorbed by each suture was quantified.
Multifilament sutures generally provide greater knot security than monofilament sutures, which have more "memory" and can return to their original position rather than remaining as a knot. Sutures usually are weakest at the knot, and knot strength depends upon a number of factors. (See 'Knots' below.)
Triclosan-coated versus noncoated sutures — Sutures coated with antimicrobial compounds may decrease the rates of surgical site infection [11-18]. However, the development of surgical site infection following midline laparotomy is multifactorial, and manipulation of a single factor (eg, suture) is not likely to provide a significant benefit for all patients. Further studies are needed to determine which subsets of patients undergoing abdominal wall closure might benefit from triclosan-coated sutures to justify the added cost.
Various sutures including polyglactin 910 (Vicryl), polydioxanone (PDS), and poliglecaprone (Monocryl) coated with triclosan (5-chloro-2-[2,4-dichlorophenoxy] phenol) have been used and appear to perform technically as well as standard sutures. A systematic review and meta-analysis that included 17 trials involving 3720 patients undergoing a variety of procedures (including nonabdominal surgery) found a significantly lower risk of surgical site infection for triclosan-coated versus noncoated sutures (relative risk [RR] 0.70, 95% CI 0.57-0.85) [17,18]. Subgroup analysis supported the use of triclosan-coated sutures in adult (not pediatric) patients, abdominal procedures, and clean or clean-contaminated (not dirty) wounds. For abdominal wound closure (n = 1562), triclosan-coated sutures reduced the rate of surgical site infection from 9.8 to 7.6 percent (RR 0.50, 95% CI 0.50-0.97).
However, a later multicenter German trial randomly assigned 1224 patients to polydioxanone suture without triclosan (PDS-II) or polydioxanone with triclosan (PDS Plus) for continuous closure of midline abdominal wounds in patients undergoing laparotomy for a variety of intra-abdominal conditions (PROUD trial) [16]. The incidence of surgical site infection did not differ between groups (14.8 versus 16.1 percent), nor did the rate of serious adverse events (25 versus 22.9 percent), including wound dehiscence, which can be related to surgical site infection or suboptimal technique. In this study, the majority of the cases were clean or clean-contaminated (97.8 percent in triclosan coated, 98.4 percent uncoated), and antibiotic prophylaxis was used in >98 percent of patients. Logistic regression identified extended operative procedures with a combination of target organs (colon, rectum, liver, pancreas, and stomach [OR 6.4, 95% CI 2.7-14.9]), missing antibiotic prophylaxis (OR 5.2, 95% CI 1.6-17.3), chronic renal insufficiency (OR 2.9, 95% CI 1.4-6.5), anemia (OR 1.7-2.6), increased body mass index, and surgeon expertise (OR 1.73, 95% CI 1.02-2.9) as increasing the risk for surgical site infection. Interestingly, a meta-analysis of prior trials including these results favored triclosan-coated suture (OR 0.67, 95% CI 0.47-0.98) but over a wide confidence interval. Further studies are needed to determine which subsets of patients are more likely to benefit to justify the added cost.
Another trial published after the meta-analysis that enrolled over 1000 patients undergoing gastrointestinal surgery found that abdominal wall closure with triclosan-coated sutures did not reduce the incidence of surgical site infection (6.9 percent triclosan versus 5.9 percent control) [19].
Needles — Although many types of needles are available, most are designed for very special suturing needs. Needles are classified according to shape, caliber, degree of curvature, type of point, and how the suture is attached (swaged or threaded) (figure 1). Most surgeons use only a few needle types. (See "Skin laceration repair with sutures" and "Skin laceration repair with sutures", section on 'Suture selection'.)
Straight or curved — Straight needles are used primarily for skin closure but are not commonly used. They are of the cutting variety and are designed to be handheld. Curved needles require a needle driver. They are characterized by the diameter of their arc, degree of curvature, and caliber. Degree of curvature is one-fourth, three-eighths, one-half, and five-eighths of a circle. Selection of size and curvature depends upon the tissue to be sutured and the depth of dissection. The greater the curvature, the easier it is to manipulate the needle in deep or confined spaces.
Diameter — Needle caliber is dependent upon the wire diameter from which the needle is made. These are defined as fine, medium, and heavy. Medium needles, which are sometimes called general closure needles, have utility in most tissues and are especially useful for pedicles and fascia. Fine needles are sometimes called intestinal needles because of their frequent use in gastrointestinal surgery. They are commonly used for delicate or thin tissue, small pedicles, and blood vessels. The heavy needles are often referred to as hernia needles. They are designed for use on fascia, ligaments, and other dense tissues.
Point — Most abdominal incisions can be closed with one-half or five-eighths circle, taper point, general closure needles. Hernia needles may be used if the fascia is thickened or scarred. A cutting needle is rarely necessary for standard fascial closures.
●Taper – Taper point needles are atraumatic. They create the smallest holes because the tissues are stretched and can retract around the suture. These are the most commonly employed needles and have utility in all tissues except skin.
●Blunt – Taper point needles can also be blunted. Blunt needles may give an extra measure of protection to both surgical personnel and patients from exposure to bloodborne pathogens because penetration of the skin is less likely even when penetration of gloves occurs [20,21]. Glove punctures and finger sticks with surgical needles account for up to 80 percent of accidental exposures to body fluids and potentially serious pathogens such as hepatitis B, hepatitis C, and HIV [22]. Double gloving also reduces exposure risk. (See "Prevention of hepatitis B virus and hepatitis C virus infection among health care providers" and "Management of health care personnel exposed to HIV".)
Blunt needles may be used to close fascia satisfactorily, but, because of the blunt tip, they do not immediately pierce the tissue, and extra force is usually needed [23]. On occasion, the surgeon may have to change to a traditional taper point or cutting needle.
●Cutting – Cutting needles have at least two honed edges and are used in dense or scarred tissue. These are the most commonly employed for skin closure. Care must be taken with cutting needles to prevent laceration of tissue and accidental cuts to surgical personnel. The conventional cutting needle has three sharpened edges on its surface. It cuts tissue easily in the direction of the pull of the needle.
●Reverse cutting – A reverse cutting needle has a cutting edge on its convex surface. It generally cuts tissue away from the pull of the needle. Although it may prevent accidental cutting through the tissue edges, it will produce larger holes. These needles are useful for the placement of retention sutures.
●Free versus swaged – A free needle must be threaded through an eyelet, while swaged needles are a single unit with the suture attached directly. The swaged needles may have the sutures attached to needles permanently or in a way that allows the needle to be pulled off with a gentle tug. The latter are known as control release or "pop-off" needles and may save time when numerous interrupted sutures are necessary. Swaged needles cause less tissue injury because they are smaller and always remain sharp. There is less chance of metal fatigue since they are disposable. Less handling and manipulation is needed with swaged needles, which may lower the risk of glove punctures and needle sticks.
KNOTS — Secure knots are critical for a strong closure. Most suture failures occur at the knot. Knot security is a function of how the loops and throws are configured, as well as the type and size of the suture.
Many studies have been performed to determine which sutures have the best knot security, but results are mixed. It appears that braided suture consistently tends to have better knot security compared with monofilament suture when the same size, suture, and number of knots are used.
In most situations, a single strand of suture should be tied to a single strand. Tying a single strand of suture to a double strand of suture may reduce knot security [24]. This is especially important if the suture will significantly experience tension, such as with fascia closure.
There is no benefit to the use of a surgeon's knot (a double throw in the first loop) over a square knot (figure 2) [25,26]. The primary benefit of a square knot is that it becomes tighter when the ends of the suture are pulled [25]. Although knots are the weakest part of the suture, square knots maintain 90 percent of the tensile strength of untied sutures. If nonidentical sliding knots are used, then six throws are needed for adequate knot security [24].
Knots always provide space in which bacteria can become enmeshed and therefore are the most common site of sinus formation. Early attempts to exploit greater tensile strength of nonabsorbable sutures were thwarted by the frequency of suture sinuses when natural fiber multifilament sutures were used. The risk of sinus formation may approach 80 percent if a contaminated wound is closed with natural multifilament suture [27].
A lower risk of suture sinus formation with synthetic suture was illustrated in a study that compared continuous closure using polydioxanone (PDS) with interrupted closure using braided silk in clean and contaminated abdominal wounds [28]. The incidence of sinus formation was 1.3 percent in the PDS group compared with 7.1 percent in the silk group. Also, sinus formation following use of PDS healed within one week after percutaneous drainage alone without removal of the suture, whereas sinus formation associated with braided silk required excision of the sinus tract and removal of the infected suture. Wound dehiscence, early wound infection, and incisional hernia did not differ significantly between the two groups.
Additionally, the use of absorbable suture may eliminate palpation of the knot through the skin, a potentially distressing problem in thin patients.
WOUND CLOSURE TECHNIQUE BY LAYER — The method of closure of the abdominal wall is a critical aspect of an effective incision closure, in addition to choice of suture material. Layered closure is described as the separate closure of the individual component of the abdominal wall, specifically the peritoneum and distinct musculoaponeurotic layers, whereas mass closure is the closure of all layers of the abdominal wall (except the skin) as a single structure. An evidence-based review identified three separate meta-analyses, each of which found that mass closure was associated with a lower incidence of incisional hernia [6,29-31]. In addition to mass closure, this review determined that the optimal method of abdominal wall closure is mass closure using absorbable suture in a simple running technique with a suture length to wound length ratio of 4 to 1. (See 'Mass closure' below.)
Peritoneum — Surgical closure of the peritoneum does not impact incision strength or healing. There is overwhelming evidence from randomized trials that peritoneal closure is unnecessary because the peritoneum reepithelializes within 48 to 72 hours [32-34]. Furthermore, peritoneal closure results in more advanced adhesion formation at the time of a subsequent procedure [35]. (See "Postoperative peritoneal adhesions in adults and their prevention".)
Also, there are insufficient data to suggest that aggressive peritoneal lavage is beneficial if there is no gross contamination [36]. Lavage may impede host defenses and spread previously localized infection.
Fascia — The fascia is the most critical layer because this tissue provides the greatest wound tensile strength during healing.
Tensile strength of the fascial wound — The inflammatory process at the wound edge produces collagenase, which assists digestion of necrotic debris but also results in lysis of collagen and partial digestion of fascia. During these first few postoperative days, tensile strength of the sutured wound may actually decline by as much as 50 percent before a slow increase in tensile strength begins [37,38]. (See "Basic principles of wound healing", section on 'Wound healing'.)
Tensile strength of a wound follows a characteristic nonlinear pattern and depends upon the synthesis of new connective tissue by fibroblasts (figure 3). Adequate blood supply is critical to supply nutrients and oxygen. Wounds have less than 5 percent of the tensile strength of unwounded tissue in the first postoperative week; thus, wound security is dependent solely upon suture that has been secured in strong healthy tissue. Maximum strength rarely, if ever, exceeds 80 to 90 percent of intact fascia. Fortunately, only 15 to 20 percent of maximum strength is necessary for normal daily activities [39]. Since return of tensile strength can take more than 70 days, sutures that maintain their strength for at least this length of time are preferred. Therefore, most surgeons select a delayed absorbable or nonabsorbable suture for abdominal wall closure. (See 'Materials' above.)
Technique — Fascial closure should reapproximate the wound edges without undue tension or tissue ischemia. Although interrupted closure has the advantage of not relying on the security of a single knot, this technique is associated with tissue ischemia due to an uneven distribution of tension. Fortunately, dehiscence due to knot slippage is rare [40]. Continuous closure distributes tension evenly along the entire length of the incision, allows better tissue perfusion, and saves time. A meta-analysis evaluating midline abdominal closure techniques supports closure of elective midline incisions with a continuous technique using slowly absorbable sutures [7]. (See 'Midline' below.)
The amount of suture used depends upon the size of each stitch (ie, distance from fascial edge) and stitch interval (ie, space between stitches). For continuous closure, the total length of the suture should be approximately four times the length of the incision [41,42]. The use of a shorter length suture due to a reduced stitch size and/or stitch interval increases the risk of hernia formation [42-44]. In a randomized trial, the incidence of hernia formation (9 versus 21.5 percent, respectively) was lower when the suture length/wound length (SL/WL) ratio was ≥4 compared with <4 [43].
Regardless of whether interrupted or continuous closure is chosen, sutures should be placed approximately 10 mm from the fascial edge. Suture widths in excess of 10 mm may increase the magnitude of compressive forces on the tissue contained between the suture hole and fascial edge [45].
In Europe, a further reduction in suture width from 10 mm to 5 to 8 mm is advocated by the 2015 European Hernia Society guidelines on the closure of abdominal wall incisions [41], largely based upon the results of two randomized trials [42,46].
●A randomized trial comparing long stitch width (>10 mm) with shorter stitch width (5 to 8 mm) identified longer stitch width as an independent risk factor for the development of both incisional hernia and surgical site infection [42]. Incisional hernia occurred in 49 of 272 patients (18.0 percent) in the long stitch group and in 14 of 250 (5.6 percent) in the short stitch group.
●In a second trial (STITCH), 560 patients were randomly assigned to undergo continuous suture closure of a midline incision with either a long (10 mm) or short (5 mm) suture width [46]. Significantly fewer patients in the short, compared with long, suture width group developed incisional hernia at one year (13 versus 21 percent). The rates of complications (including surgical site infections) were not different.
Further studies with different needle/suture types, as well as with a longer follow-up, are required before a suture width of less than 10 mm can be recommended for routine closure of all midline incisions.
Retention sutures have traditionally been used in wounds thought to be at a high risk for dehiscence, but data consistently supporting this technique are lacking, and this technique is associated with increased wound complications and difficulty with ostomy placement and care. (See "Complications of abdominal surgical incisions".)
Mass closure — Mass closure may be performed in either a continuous or interrupted fashion. Mass closure significantly reduces the incidence of wound dehiscence and is performed by incorporating a small amount of subcutaneous fat, rectus muscle, rectus sheaths, transversalis fascia, and, optionally, the peritoneum. Techniques for mass closure include the Smead-Jones and continuous single or double loop closures.
Continuous mass closure with nonabsorbable or slowly absorbable suture is safe and as effective as interrupted techniques (figure 4). In addition, studies in animals and humans have found continuous mass closures to be faster and more cost effective [47-49].
To perform the Smead-Jones closure, sutures are placed in a vertical mattress fashion. Continuous double loop mass closure may be superior to single loop mass closure. A study that compared the double and single loop mass closure in midline laparotomy wounds reported that wound dehiscence was 0 with the continuous double loop closure technique compared with 8 percent for single loop mass closure [50].
Prophylactic mesh — The incidence of incisional hernia following laparotomy varies widely and depends upon the patient's risk factors for hernia formation and the nature of the surgery, with most studies reporting rates between 10 and 15 percent [51]. (See "Clinical features, diagnosis, and prevention of incisional hernias", section on 'Epidemiology and risk factors'.)
For high-risk patients (eg, those with obesity or undergoing open abdominal aortic aneurysm repair), there has been some interest in placing mesh prophylactically at abdominal wall closure to prevent incisional hernia formation. However, no data are available regarding potential long-term adverse outcomes, such as chronic pain and mesh complications. Given these limitations, we do not place mesh prophylactically at the time of abdominal wall closure. Data on prophylactic mesh use are presented elsewhere. (See "Clinical features, diagnosis, and prevention of incisional hernias", section on 'Prophylactic mesh placement'.)
Subcutaneous — A systematic review identified eight trials evaluating subcutaneous closure for non-cesarean delivery, concluding that the low-quality evidence available was insufficient to support or refute subcutaneous closure [52]. By eliminating dead space, closure of subcutaneous tissue may help prevent superficial wound disruption, which is often associated with wound seroma, hematoma, or infection. Meticulous attention to control of subcutaneous bleeding or the use of closed suction drainage can help prevent the development of hematoma or subcutaneous fluid collection and may have a similar effect on wound disruption as subcutaneous closure [53,54], although this is controversial [55]. Further randomized trials with stratification for incision type and other components of perioperative care (eg, use of antibiotics, type of suture material) are needed to examine these approaches.
A trial of 456 elective laparotomies found that wound irrigation with 0.04% polyhexanide solution reduced surgical site infection rate compared with saline irrigation (34.7 versus 21.5 percent) [56].
Skin — Closure of the skin may be performed with subcuticular suture, stainless steel staples, subcuticular absorbable staples, surgical tape, or wound adhesive glue.
Subcuticular closure obviates the need to remove surgical staples, is more comfortable for the patient, and is less costly [57]. Whether subcuticular suture results in a more cosmetically pleasing scar is debated [58,59]. Suture knots have potential disadvantages in subcuticular wound closure because they may cause tissue ischemia, act as a nidus for infection, and can extrude through the skin weeks after surgery. One option is to anchor the suture above the skin away from the incision. Another alternative is self-anchoring barbed polyglycolic acid or polydioxanone suture (Quill, Contour Thread), which requires no knots [60]. These have a similar cosmetic and safety profile as conventional suture but avoid the drawbacks inherent to suture knots [60].
Staples are quicker to place, give an acceptable cosmetic result, are associated with a low rate of infection, and allow small portions of the wound to be opened easily when needed [61]. Staple closure is less likely to obscure wound drainage and impending separation compared with subcuticular closures but is more likely to be a source of postoperative pain [57]. Staples are preferred for reentry incisions. An experimental study found no staple displacement or increase in skin temperature for stapled closure exposed to magnetic resonance imaging [62].
Absorbable staples (eg, Insorb) potentially combine the benefits of subcuticular closure with the speed and precision of staple placement [63]. In a study that compared skin incision closure by absorbable subcuticular staples, cutaneous metal staples, and polyglactin 910 suture in a pig model, absorbable subcuticular staples induced a less severe inflammatory response in the early stages of healing.
Surgical tape and adhesives are alternatives to suture or staples. In particular, use of tissue adhesives, such as octyl cyanoacrylate (Dermabond) and butylcyanoacrylate (Histoacryl), may potentially save time and have wound infection rates and cosmetic outcomes that are comparable to those of nonabsorbable monofilament sutures [64]. A systematic review supported these findings but also noted that the tissue adhesives are associated with a small but significant increased rate of wound dehiscence, which must be considered when choosing the closure method [65]. (See "Minor wound repair with tissue adhesives (cyanoacrylates)".)
WOUND CLOSURE BY INCISION TYPE — Abdominal wall incisions are generally closed using the principles described above; however, there are a few points specific to the type of incision.
Midline — We suggest placing the omentum beneath a longitudinal incision to reduce the risk of adhesions between bowel and the anterior abdominal wall. The posterior rectus sheath is included in the fascial closure to increase tensile strength of the closure.
To minimize the risk of incisional hernia, elective midline abdominal closure (first operation or reoperation) should be performed using a continuous technique with slowly absorbable sutures. A meta-analysis of 14 randomized trials of midline fascial closure in 7711 patients compared the incidence of incisional hernia for elective abdominal wall closure performed with continuous versus interrupted closure, rapidly absorbable versus slowly absorbable, and nonabsorbable versus slowly absorbable suture [7].
Rapidly absorbable sutures included polyglactin 910 (Vicryl) and polyglycolic acid (Dexon). Slowly absorbable sutures included polydioxanone (PDS, MonoPlus) and polyglyconate + trimethylene carbonate (Maxon). Nonabsorbable sutures included polyamide (nylon), polypropylene (Prolene), and polyester (Ethibond) (table 2).
Results were as follows:
●The incidence of incisional hernia was significantly higher in the interrupted compared with continuous closure group (12.6 versus 8.4 percent) regardless of the type of suture material used (ie, absorbable versus nonabsorbable).
●The incidence of incisional hernia was significantly lower for absorbable sutures compared with nonabsorbable sutures (6.1 versus 26.3 percent) regardless of suture technique (ie, continuous versus interrupted).
●The incidence of incisional hernia was significantly lower for slowly absorbable sutures compared with rapidly absorbable sutures (8.1 versus 10.8 percent) regardless of suture technique (ie, continuous versus interrupted).
No conclusions could be drawn regarding optimal closure techniques for abdominal closure in an emergency setting.
Since this meta-analysis, another trial randomly assigned 456 patients to closure of the midline abdominal fascia to nonabsorbable (polypropylene; Prolene) or absorbable (polydioxanone; PDS) suture material. In contrast, there were no significant differences in the incidence of incisional hernia or secondary outcomes measures between the groups [66]. This trial included both emergency and elective cases and did not stratify the analysis.
A 2017 Cochrane review of 55 randomized trials (19,174 patients) compared absorbable versus nonabsorbable sutures, continuous versus interrupted closure, mass versus layered closure, monofilament versus multifilament sutures, and slow versus fast absorbable suture in terms of incisional hernia (at one year), wound infection, wound dehiscence, wound sinus, or fistula formation. The only significant findings were that monofilament sutures may reduce the risk of incisional hernia (relative risk 0.76, 95% CI 0.59-0.98) and that absorbable sutures may reduce the risk of sinus or fistula tract formation (relative risk 0.49, 95% CI 0.26-0.94). However, only about one-half of the included trials (26) enrolled patients who underwent midline incisions exclusively; the others included patients who underwent paramedian, subcostal, or transverse incisions [67].
Transverse
Upper abdominal transverse incision — A randomized trial of 268 patients undergoing upper abdominal transverse incision closure compared mass versus layered continuous closure [68]. Layered closure resulted in a lower incidence of surgical site infection (6 versus 18 percent). The follow-up was too short to detect incisional hernias.
Pfannenstiel and Cherney incision — The Pfannenstiel and Cherney incisions are closed in a similar manner. The rectus muscles will usually approximate themselves, but if rectus diastasis is present, the muscles can be pulled to the midline with several loosely tied absorbable sutures. The aponeurosis is closed with interrupted or continuous suture. Both absorbable and nonabsorbable sutures have been used for closure. Skin can be reapproximated by any method. A subcuticular technique using 4-0 suture is easily performed since the edges are readily brought together.
The only difference for the Cherney incision is the need to reattach the tendons to the lower aponeurosis of the anterior rectus sheath rather than to the periosteum of the symphysis directly. One option for this is horizontal mattress sutures of 2-0 permanent suture material; delayed absorbable sutures are an alternative.
Maylard incision — With the Maylard incision, oozing from the cut muscle and extensive tissue fluid collection may rarely be significant enough to warrant placement of a closed suction drainage system under the fascia. The drain is brought out through a stab wound separate from the incision. The fascia may then be closed with interrupted or continuous sutures, usually of 1 or 0 suture caliber. Permanent or delayed absorbable suture is preferred, and a mass closure technique can be used. A common method is closure of the fascia with running permanent suture of 0 suture caliber in a mass technique and closing the skin using a subcuticular technique with absorbable 4-0 suture.
Oblique — Oblique incisions (eg, McBurney) are muscle splitting; therefore, the muscles reapproximate by their own contraction when anesthetic paralysis resolves. The wound would likely heal with skin closure only; however, we suggest a deep simple closure. The internal oblique and transversus abdominis are approximated with loosely tied absorbable sutures spaced 1 cm apart in the internal oblique layer. The external oblique aponeurosis can be closed with interrupted or continuous 2-0 absorbable sutures. The skin can be closed by any method. When oblique incisions are used in the face of intra-abdominal infection, delayed primary closure should be considered (figure 5) [69]. Alternatively, the skin can be closed with staples so that the incision can be easily be reopened, as needed.
DRAINS — Prior to closure, it may be necessary to place temporary drainage systems. Drains are categorized as passive or active, meaning that they rely upon gravity or negative pressure suction, respectively. Examples of passive drains include the Penrose drain, Foley catheter, Word catheter, and Malecot catheter. Active drains may be open (eg, Salem sump) or closed systems (eg, Jackson-Pratt). One disadvantage of open systems is the potential for bacterial contamination of the tubing. Therefore, most surgeons prefer closed systems with negative pressure suction. Because closed suction systems (figure 6) require smaller incisions, herniation is uncommon.
The primary indication for the placement of a drain is the prevention of fluid collection and subsequent infection. Intra-abdominal procedures frequently associated with large collections of blood and serum (eg, hepatic, pancreatic surgery) may benefit from prophylactic drainage. Drains are placed adjacent to the injured tissue (eg, liver, pancreas) or in the vicinity of an anastomosis at risk for leakage (ie, choledochoenteric, pancreaticoenteric). Other procedures that may require drainage include radical pelvic surgery, entry into the space of Retzius, or muscle-splitting incisions. Although the data are mixed, randomized trials and meta-analyses have found that closed drainage of the subcutaneous tissue does not prevent significant wound complications [70,71].
Thus, the value of prophylactic drains remains controversial. Complications from drains may include infection, hemorrhage, kinking, and hernia formation. Good surgical technique with adequate hemostasis, the elimination of dead space, and the use of prophylactic antibiotics obviate the need for drains in most patients.
Irrigation of wounds with antibiotics initially was thought to lower the incidence of wound infection, but contemporary reviews suggest there is no benefit to routine irrigation of a midline wound, provided the patient received appropriate antibiotic prophylaxis [72]. Additionally, antibiotic solutions are toxic to the cellular elements necessary for healing. For this reason, delayed closure of an abdominal incision with or without the use of a negative pressure wound system is an alternative to irrigation in certain circumstances. (See "Negative pressure wound therapy".)
Placement — Drains should be placed through a small incision separate from the primary incision (figure 7) [1]. The drain should have a direct path to prevent kinking and subsequent obstruction. Care must be taken to avoid injury to the abdominal wall vessels (eg, epigastric), which can lead to significant bleeding. A stab wound involving the rectus sheath must be adequate to prevent kinking of the drain and to allow its removal, but not so large that a hernia may form. Normally, an incision greater than 5 mm but less than 10 mm is ideal. Care must also be taken to avoid suturing the drain to the fascia during closure. Once placed, the drain should be properly dressed and placed in a position that avoids traction and potential fracture [73].
WOUND PACKING — Contaminated wounds should generally be packed open. (See "Basic principles of wound management", section on 'Wound packing'.)
Options for wound closure include healing by secondary intention, which requires ongoing wound packing, negative pressure wound therapy, or delayed primary closure. Whether primary closure necessarily leads to a higher incidence of surgical site infection under this circumstance has not been definitively proven. A systematic review identified eight trials that randomly assigned patients to primary closure or delayed primary closure following a variety of procedures, including perforated appendicitis, perforated viscus, ileostomy closure, trauma, and intra-abdominal abscess [74]. Primary closure appeared to increase the risk for surgical site infection; however, significant heterogeneity was noted, and with a random (rather than fixed) effects model, the effect was no longer significant.
DRESSINGS — A sterile dressing is generally used to protect the closed surgical wound for 24 to 48 hours postoperatively. There are no convincing data to suggest that one type of dressing is better than another with respect to surgical site infection (SSI). Systematic reviews have found no significant difference in SSI rates for surgical wounds covered with different dressings (basic wound contact dressing, film dressing, hydrocolloid dressing) and those left uncovered for a variety of wound conditions (clean, mixed contamination levels) [75,76]. As such, the choice of surgical wound dressing should be made with regard to the ability of the dressing to manage absorption of exudate upon the nature of the surgical wound and any properties and qualities that a particular dressing can offer. Although the dry sterile dressing has been a standard for decades, wounds heal better in a moist environment. Thus, modern film dressings that are impermeable to fluid and bacteria but allow passage of moisture vapor may be preferable [1,77]. These do not appear to increase the frequency of wound infection, and they permit visual assessment of the wound and improved patient comfort. (See "Basic principles of wound management", section on 'Common dressings'.)
Negative pressure dressings — Following their use in orthopedic and sternal surgery [78], negative pressure dressings have been applied to closed abdominal wounds in general and colorectal surgery [79-81]. In a systematic review and meta-analysis of five randomized trials and 16 nonrandomized comparative studies (2930 patients), negative pressure dressings, when used on closed abdominal incisions, were associated with reduced surgical site infections (pooled risk difference -12 percent, 95% CI -17 to -8 percent) [82]. The benefit was more pronounced in studies with an infection rate of 20 percent or greater in the control arm; the significance was lost when pooling only high-quality observational studies (642 patients) or randomized trials (527 patients).
Further studies are required to identify the patient population that would benefit most from the negative pressure dressings (eg, patients with obesity or contaminated wounds). Routine use of negative pressure dressings after abdominal closure is costly and therefore will need to be justified by a significant reduction in complication rates. One study found the use of negative pressure dressings cost effective in the treatment of high-risk abdominal wounds [83].
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Abdominal incisions and closure".)
SUMMARY AND RECOMMENDATIONS
●The suture chosen for closure should be absorbable and have a caliber that will provide adequate strength to the wound while minimizing foreign body content. Multifilament sutures provide better knot strength but are more prone to infection and sinus formation. (See 'Sutures' above.)
●Most abdominal incisions can be closed with one-half or five-eighths circle, taper point, general closure needles. Hernia needles can be used if the fascia is thickened or scarred. A cutting needle is rarely needed for standard closures. (See 'Needles' above.)
●Continuous mass closure is the ideal closure method using a suture length to wound length ratio of 4:1 in a simple running technique. The tissue should be reapproximated with low tension to prevent ischemia. A single strand should be tied to another single strand using a square knot or surgeon's knot. (See 'Fascia' above and 'Knots' above.)
●We suggest not closing the peritoneum, as this appears to confer no benefit (Grade 2C). (See 'Peritoneum' above.)
●To reduce the incidence of incisional hernia following elective midline abdominal closure (first-time closure or repeat closure), we recommend a continuous suture technique using slowly absorbable monofilament suture (Grade 1A). The optimal closure technique in the emergency setting has not been defined. The fascia of nonmidline abdominal incisions can be closed in a similar fashion. (See "Complications of abdominal surgical incisions", section on 'Suture'.)
●There appears to be no benefit to subcutaneous closure. Good surgical technique with adequate hemostasis and the use of prophylactic antibiotics obviate the need for drains in most patients. (See 'Subcutaneous' above and 'Drains' above.)
●Staples, subcuticular suture, and tissue adhesives are appropriate for skin closure; the wound should be covered with a semipermeable film or hydrocolloid dressing. (See 'Skin' above and 'Dressings' above.)
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