The Difficult Abdominal Wall

Suture Material

Abdominal wall closure has changed over time in large part due to improvements in suture materials and characteristics. The ideal suture material for abdominal wall closure is one that resists infection, provides adequate tensile strength to prevent abdominal wall disruption, minimizes tissue damage, and is absorbable. In current practice, a significant percentage of abdominal wall incisions are closed with slow-absorbing monofilament sutures such as polydioxanone (PDS, Ethicon, Johnson & Johnson). Polydioxanone has an advantage over polyglactin with longer strength retention profile and absorption time, as well as being a monofilament that may resist infection to a greater degree than the braided suture. Use of nonabsorbable sutures for abdominal closure (e.g., polypropylene) has been associated with increased patient pain and sinus tract formation, and their use has shown no significant difference in the incidence of incisional hernia formation, wound dehiscence, or surgical site infection (SSI) as compared to that of absorbable suture. ^,

Barbed sutures are increasingly being used for fascial closure. This suture has tiny barbs in a helical arrangement that allow an even distribution of tension across the incision rather than just at the knots. In a porcine model, barbed and smooth sutures had a similar burst strength. Barbed sutures have also been shown to have a similar hernia recurrence rate in fascial plication for rectus diastasis. They are secured without knots, thus allowing for faster placement, and eliminate the knot as a nidus for infection. ^,

Closure Technique

The principles of wound closure applied for the closure of the abdominal wall are essentially the same for closure of any surgical incision. Minimization of tissue damage is imperative, and this may be done by limiting the incorporation of the abdominal wall musculature in the closure. A 4:1 ratio of suture to wound length has been advocated. Recent evidence suggests that a strategy of taking smaller (5 mm) bites with smaller (5 mm) space between them is associated with a lower rate of incisional hernia. ^, This strategy achieves a ratio of suture to wound length even greater than 4:1. Layered closure of the abdominal wall to include separate layered closure of the peritoneum and subcutaneous tissues in addition to the skin and fascia is discouraged, and mass closure is preferred. A continuous suture of slowly absorbable suture material is the recommended method of closure in elective abdominal surgery, although there is little evidence to guide closure in the emergency setting.

Although retention sutures are frequently employed, there is little evidence to suggest benefit to their use. While they are intended to prevent evisceration, there is no consensus on the ideal adjunct to standard techniques of abdominal wall closure. Retention sutures have been associated with increased pain, increased wound inflammation, wound complications and skin breakdown, and problems with ostomy appliance placement. Thus, routine use of retention sutures, while theoretically advantageous, is not without potential complications. Patients at high risk of acute fascial dehiscence may benefit from some method of evisceration prophylaxis, and some have promoted the use of synthetic mesh in high-risk abdominal wall closures. Identification of the patient who is at higher risk of abdominal wall dehiscence may alter surgical technique of abdominal wall closure and should be considered in any abdominal operation.

Prophylactic Mesh

With incisional hernia rates after midline laparotomy in high-risk groups of 30% or more in some series, placement of prophylactic mesh at the index laparotomy for high-risk patients has drawn a large interest. Both the onlay and sublay positions have been utilized for this purpose. In multiple studies, there is a decrease in incisional hernia rates when a mesh is utilized, with no increase in surgical site occurrence (SSO) rates. Postoperative seroma rates are increased in the population that undergoes mesh placement, particularly in the onlay position. Additionally, prophylactic mesh placement has been shown to be cost effective.

Abdominal Fascial Dehiscence

The incidence of fascial dehiscence has been reported in the literature to be between 3% and 3.5% after major abdominal surgery and is associated with significant morbidity and mortality. Acute fascial dehiscence may be heralded by increased serosanguinous drainage from the laparotomy wound and often can be confirmed on physical exam ( Fig. 18.1 ). Patient risk factors and disease/surgical risk factors for abdominal wall suture complications are illustrated in Boxes 18.1 and 18.2 . Several different multifactor scoring systems predictive of abdominal wall suture complications have been described in the literature, including the Veterans Affairs Medical Center (VAMC) score and the Rotterdam score.

Surgical management of acute dehiscence is based on the underlying cause, with SSI and intraabdominal abscess being the most common. The technical causes of acute fascial dehiscence are knot failure and fascial damage related to tension, ischemia, or suture material failure. Although the risk of fascial dehiscence may persist beyond 3 weeks postoperatively, the usual time frame is within the first 7 days after primary closure.

There is no consensus management strategy for fascial wound dehiscence. The decision to proceed with immediate or delayed primary fascial closure is based on the infectious source (if one is present) and the appearance of the wound. If a superficial wound infection is the source, drainage and local wound management with dressing changes are often used. Once the infectious source is dissipated, placement of a negative pressure wound therapy (NPWT) can be effective in promoting granulation tissue and closure at the expense of developing an incisional hernia that would require delayed repair. Alternatively, operative debridement and delayed primary fascial repair, if feasible, can lead to faster healing and decreased incidence of ventral hernia.

Depending on the degree of any intraperitoneal inflammation, the abdomen may be inaccessible for repeated laparotomy at the time of dehiscence. This should then be managed as a planned ventral incisional hernia, with reconstruction in a delayed fashion, once the acute physiologic process has dissipated. The use of a biologic mesh to bridge the fascial defect in this circumstance is discussed later in the chapter.

Temporary Abdominal Closure

Damage control laparotomy is now a well-established method to control hemorrhage and contamination at the index operation, replete physiologic reserve, and then restore abdominal continuity thereafter. In civilian trauma, between 8.8% and 36.3% of patients undergoing a trauma laparotomy require a damage control procedure during the preliminary procedure and thus a method of temporary abdominal closure (TAC). Techniques in damage control have become standard adjuncts in trauma, general surgery, and subspecialty surgical procedures. Indications for TAC are shown in Box 18.3 , and current options for TACs are illustrated in Table 18.1 .

The goal of all TAC techniques is to minimize damage to the abdominal contents and minimize adherence of abdominal contents to the anterior abdominal wall while retaining the ability to close the fascia primarily at a subsequent operation. Current options for TAC include a tension-free, atraumatic abdominal visceral coverage using the vacuum-pack technique popularized by Barker, commercially available vacuum systems (VAC or ABThera, KCI International, San Antonio, TX), or the use of dynamic techniques in which the fascial edges are closed with serial plication. This includes serial suture closure starting at the upper and lower edges of the incision, use of absorbable or nonabsorbable synthetic mesh, an artificial Velcro/burr technique (Wittmann Patch, Star Surgical, Burlington, WI) with or without a dynamic retention suture, or silicone elastomer techniques (TAWT, Star Surgical, or ABRA System, Canica Design, Inc., Almonte, Ontario, Canada).

A recent systematic review of publications on TAC management reported that the Wittmann patch, dynamic retention sutures, and VAC methods all have similar pooled delayed primary fascial closure rates of 78% (8 series), 71% (3 series), and 61% (38 series) respectively. However, this was a heterogeneous patient population with a lack of technique uniformity and outcome definitions.

NPWT has gained wide acceptance for the use in a variety of complex abdominal wall circumstances ( Fig. 18.2 ). In a contaminated environment, NPWT techniques have the ability to remove peritoneal fluids rich in inflammatory mediators, reducing the concentration of intraperitoneal cytokines. Several studies have shown that in an inflamed setting, this method achieves the highest delayed primary closure rate, lowest mortality, and lowest incidence of enterocutaneous fistula formation. The artificial burr and dynamic retention suture techniques prevent lateral fascial retraction and can be sequentially tightened to allow eventual fascial closure without undue tension. A significant disadvantage of any these techniques is their requirement to be sutured to the abdominal wall musculature and fascia, which may complicate future reconstructive procedures. Incorporating dynamic serial fascial closure in conjunction with commercial NPWT has demonstrated 90% delayed primary fascial closure rates. This technique extends beyond the 8-day benchmark, with low complications rates in several series.

Our five-stage management algorithm has helped minimize variability in patients with an open abdomen, with the goal to successfully close the abdominal fascia during Stage 3 of this algorithm in the majority of patients ( Fig. 18.3 ). Staging of abdominal reconstruction serves several vital functions: intensive care unit resuscitation, reduction of contamination and control of intraabdominal sepsis, debridement of devitalized or contaminated tissue, and allowance for decisions on subsequent reconstruction.

The goal of delayed primary fascial closure is to have the fascia closed as soon as possible, ideally within the first 8 days, to minimize complications related to the open abdomen management. However, the risk for development of intraabdominal hypertension and abdominal compartment syndrome from an ongoing inflammatory response, visceral edema, retraction of abdominal wall musculature (loss of domain), lack of source control, intra-abdominal abscess, or enterocutaneous fistula may all be reasons to delay primary closure. In this setting, the surgeon may have to accept a planned delayed abdominal wall reconstruction and use alternative means of visceral coverage (Stages 4 and 5).