Management of the open abdomen in adults

INTRODUCTION — The term "open abdomen" refers to a defect in the abdominal wall that exposes the abdominal viscera. Damage control surgery associated with trauma and abdominal compartment syndrome are the most frequent reasons for leaving an abdomen open. Open abdomen exposes the viscera and leads to fluid and heat loss, which can be reduced with temporary abdominal closure techniques until the abdomen can be closed primarily, closed functionally, or graft coverage of the exposed viscera can be provided.

The care of the patient with an open abdomen, techniques for placement of temporary abdominal dressings, and timing and methods of abdominal closure will be reviewed here. The diagnosis and management of abdominal compartment syndrome is discussed in detail elsewhere. (See "Abdominal compartment syndrome in adults".)

OPEN ABDOMEN — Open abdomen is an abdominal wall defect created by intentionally leaving an abdominal incision open at the completion of intra-abdominal surgery or by opening (or reopening) the abdomen because of concern for abdominal compartment syndrome. Open abdomen can also be the result of injuries to the abdominal wall that produce significant soft tissue defects. The indications for open abdomen vary from region to region. As an example, in the United States, the most common indication for open abdomen is damage control surgery related to managing abdominal trauma [1], whereas in a review from the United Kingdom, the most common indication for open abdomen was abdominal sepsis [2].

Open abdomen is managed with temporary abdominal closure using one of several techniques, followed by interval abdominal closure, preferably by bringing the edges of the abdominal fascia together primarily (primary closure) or, if this is not feasible, using a functional closure or simple coverage. The techniques of temporary closure and closure of the abdomen are discussed below. (See 'Temporary abdominal closure' below and 'Abdominal closure' below.)

Etiologies — The most common circumstances that result in open abdomen include the following:

Damage control surgery — Damage control is an operative strategy that is used to manage immediately life-threatening conditions by delaying definitive management of less severe injuries until the patient is physiologically capable of withstanding repair/reconstruction. This strategy is used most frequently in severely injured or critically ill patients who are hemodynamically unstable. Because a repeat procedure is required for definitive repair, the abdomen is left open to facilitate reexploration, which is generally delayed until hypovolemia, hypothermia, and coagulopathy are corrected [3-8]. Leaving the abdomen open also obviates abdominal compartment syndrome. (See "Overview of damage control surgery and resuscitation in patients sustaining severe injury".)

Abdominal compartment syndrome — Intra-abdominal hypertension (IAH) and abdominal compartment syndrome can be due to any process that increases the volume of the confined space of the abdominal cavity [9-12]. Increased volume in the abdomen is typically the result of an increase in interstitial fluid as is seen with large volume resuscitation, but space occupying fluid (blood or ascites) in the peritoneum or retroperitoneum can also contribute [13]. Abdominal compartment syndrome, including its etiology and strategies for prevention, is discussed elsewhere. (See "Abdominal compartment syndrome in adults", section on 'Risk factors and classification'.)

Septic abdomen — Bowel perforation with severe contamination of the peritoneal cavity can result in recurrent intra-abdominal sepsis and postoperative abscess formation in spite of aggressive abdominal irrigation. Under this circumstance, it may be desirable to leave the abdominal wall open and use negative pressure wound therapy to maintain domain as well as to remove residual or reaccumulating fluid. The temporary abdominal dressing facilitates access for repeated abdominal exploration and abdominal irrigation, as needed. This management strategy is associated with a reduced risk of postoperative infection and improvement in the success rate of definitive fascial closure [14-17]. (See "Complications of abdominal surgical incisions", section on 'Delayed closure'.)

Refractory intracranial hypertension — A more controversial indication for open abdomen is refractory intracranial hypertension associated with traumatic brain injury. This indication is based upon case reports and small case series that suggest that the abdominal decompression lowers venous pressures, augmenting venous outflow from the head and decreasing intracranial pressure [18]. (See "Management of acute moderate and severe traumatic brain injury", section on 'Intracranial pressure management'.)

Complications of open abdomen — Leaving the abdomen open, when indicated, is beneficial but is also associated with complications related to fluid efflux from the abdomen, exposure of the bowel, and abdominal muscle retraction. Appropriate judgment should include a risk/benefit assessment.

●Fluid loss – A significant amount of fluid can be lost through an open abdomen. If a closed suction system is used as a part of the temporary abdominal closure, this fluid can be quantified and included in the assessment of daily fluid balance and the patient's fluid intake adjusted to prevent hypovolemia. Some temporary abdominal closure systems do not have the ability to collect and quantify fluid losses (eg, Bogota bag). (See 'Techniques' below.)

●Protein loss – The fluid that is secreted by the peritoneum is rich in protein with approximately 2 grams of protein lost from the abdomen for each liter of fluid removed [19]. These losses must be accounted for in the patient's nutrition plan.

●Fistula formation – With open abdomen, the bowel is frequently manipulated and is at risk for injury [20,21]. The incidence of enterocutaneous or enteroatmospheric fistula may be as high as 20 percent and can occur as early as eight days from the initial laparotomy [22,23]. Patients with a bowel anastomosis are at the highest risk. Whenever possible, bowel anastomoses should be covered by omentum or other viscera and protected from exposure to air as well as any materials associated with the temporary abdominal closure. In addition, mesenteric blood flow should be optimized while the abdomen is open to minimize fistula formation, particularly in the presence of newly created enteric anastomoses [24].

●Loss of domain – With open abdomen from a midline abdominal incision, the musculature of the abdominal wall retracts the fascia laterally. Once the indication for the open abdomen has resolved, the fascia (and sometimes skin) may not be able to be brought back to the midline for primary closure, resulting in a large ventral hernia (picture 1). The use of a negative pressure wound system helps to counteract the lateral forces on the abdominal wall and may allow primary closure of the fascia and skin or, if primary closure is not possible, at least decrease the size of the resultant hernia. The repair of incisional hernia is discussed in detail elsewhere. (See 'Negative pressure wound systems' below and "Overview of abdominal wall hernias in adults", section on 'Ventral incisional hernia'.)

TEMPORARY ABDOMINAL CLOSURE — Once a decision has been made to leave the abdomen open (or reopen it), the abdominal defect must be covered, which is termed temporary abdominal closure. The main goal of temporary abdominal closure is to control fluid losses and minimize the loss of domain. It is important to remember that even with a temporary abdominal closure in place, intra-abdominal pressure can increase and abdominal compartment syndrome can recur [25,26]. The optimal method of temporary abdominal closure has not been determined, and no one method is appropriate for every clinical situation. (See 'Rates of primary fascial closure' below.)

Techniques — Several techniques for temporary abdominal closure are available, including patch closure, negative pressure systems (towel and sponge based), and silo closure [27]. Each of these techniques has advantages and disadvantages with respect to its ability to control fluid loss, frequency of dressing changes, minimizing loss of domain, ease of use, and cost. The ideal technique for temporary abdominal closure, interval between fascial closure attempts, and the number of closure attempts until an alternative strategy is tried have not been well studied. Skin-only closures are an option but are rarely used in contemporary practice. The patch or silo technique can be used alone or in combination with a negative pressure system. (See 'Negative pressure wound systems' below.)

Systematic reviews concluded that negative pressure wound therapy systems with continuous fascial traction may have better outcomes, but the overall quality of the available data is poor [1,27-30]. Among negative pressure systems, a study found a possible mortality benefit from use of a commercially available sponge-based (AbThera) compared with a towel-based (Barker) negative pressure wound therapy system [31]; however, the study design did not allow the investigators to determine the reason for this. The AbThera device may also decrease adhesion formation between the viscera and abdominal side wall due to its large plastic skirt, but there have been no studies demonstrating that this results in faster or sturdier fascial closure. (See 'Negative pressure wound systems' below.)

The authors prefer to start with a commercial negative pressure device to control and quantitate fluid efflux from the abdomen between operative attempts at fascial closure performed every 48 hours. Although the applied negative pressure counteracts some of the lateral forces responsible for loss of abdominal domain, additional adjunctive techniques may be needed to help bring the fascial edges to the midline to improve the rates of primary closure. (See 'Adjunctive fascial traction' below and 'Timing of closure' below and 'Rates of primary fascial closure' below.)

Patch techniques — Patch closure of the abdomen refers to the interposition of prosthetic material between the edges of the fascia and suturing it into place. Two main patch techniques are used to provide abdominal closure and allow easy re-entry into the abdomen. Although patching can minimize fascial retraction, control of fluid is suboptimal, and thus, patch techniques are often used in conjunction with a negative pressure system to prevent skin maceration and simplify wound care. (See 'Negative pressure wound systems' below.)

The main disadvantage of patch closure is the potential for fascial necrosis due to excess traction on the fascia, or repeated fascial suturing. Any fascial loss decreases the likelihood of future primary fascial closure. Other closure techniques that do not require manipulation of the fascia until closure may be preferred, particularly if the integrity of the fascial tissue is compromised.

The features of the two most commonly used patch systems are described below:

●Wittmann Patch – The Wittmann Patch sheet is sutured to the fascia of the abdominal wall laterally, and closure of the patch at the midline is accomplished with a Velcro-like closure (one sheet with hooks and the other with loops). As edema resolves, the hook and loop sheets are readjusted to gradually bring the fascia toward the midline. Thus, this technique can also be considered a dynamic fascial closure technique. The Wittmann Patch significantly improves delayed primary fascial closure rates [32-34]. (See 'Adjunctive fascial traction' below and 'Rates of primary fascial closure' below.)

●Polytetrafluoroethylene patch – A polytetrafluoroethylene (PTFE) patch can also be used for temporary closure. The patch is anchored to the fascia laterally, and serial plication of the patch at the midline progressively brings the fascial edges together [35-37].

Negative pressure wound systems — The use of negative pressure wound therapy (NPWT) dressings, also known as vacuum-assisted closure (VAC), is an alternative and frequently used technique for temporary abdominal closure [27,38]. The application of negative pressure opposes the lateral retraction of the abdominal musculature, minimizing loss of domain, and improves the likelihood of primary fascial closure. (See 'Rates of primary fascial closure' below.)

An inert layer (towel adhered to an adhesive sheet or elastic sponge) is placed to protect the abdominal viscera and an elastic self-adhesive sheet secured to the lateral abdominal wall to which a suction system is incorporated. These wound systems are customizable and are excellent at controlling abdominal fluid.

The general mechanism of action of NPWT, its clinical uses and contraindications, and placement and management of the device are discussed in detail elsewhere. The effectiveness of using NPWT in the management of the open abdomen is discussed below. (See "Negative pressure wound therapy".)

The essential differences between towel-based and sponge-based negative pressure systems are described briefly below.

Towel-based — Towel-based negative pressure systems ("Barker's VAC") use a surgical towel adhered to a polyethylene sheet (eg, Ioban) that is placed between the viscera and posterior aspect of the anterior abdominal wall (figure 1 and picture 2) [39-43]. Small slit perforations are made in the elastic drape to allow transfer of fluid out of the abdomen. Drain tubing is placed over the towel to capture the fluid and is connected to a closed-suction drainage system. An outer, adherent elastic layer is placed to cover the abdominal wall defect [39,41,42,44].

Towel-based system dressings are easy to apply and inexpensive. Although the system effectively controls abdominal fluid, it does not provide effective suction throughout the abdomen, and thus, fluid can accumulate within the abdominal cavity. However, mild increases in intra-abdominal volume can be accommodated without resulting in increased intra-abdominal pressure because the system is relatively compliant.

Sponge-based — Commercially available kits (AbThera and VAC therapy) contain a perforated silastic sheet to place between the bowel and abdominal wall (picture 3). A sponge is trimmed and used to fill the subcutaneous abdominal defect, and an outer self-adherent skin drape contains a suction port that is connected to a proprietary suction device (picture 4) [45]. Sponge-based systems are more expensive than the towel-based negative pressure system discussed above but provide more uniform suction throughout the peritoneal cavity and may be more effective in preventing intra-abdominal fluid accumulation.

Silo techniques — Silo techniques involve suturing a large, sterilized translucent bag to the abdominal fascia or skin. A Bogota bag (picture 5), intravenous, dialysate, or irrigation bag can be used [46]. The technique is simple and low cost, and the translucent bag allows visual inspection of the abdominal viscera. However, the technique is more time consuming compared with other techniques, fluid losses are difficult to control, and increased intra-abdominal pressure requires upsizing of the system, which requires operative replacement with a larger bag. The more contemporary literature does not describe use of this technique.

Skin-only closures — Skin-only closures using towel clamps (picture 6) or staples to reapproximate the skin were the first described methods for temporary closure of the abdominal wall/skin.

The disadvantages of skin-only closure are that it does not control fluid from the wound, the technique introduces artifacts into radiographic studies, and abdominal compartment syndrome can occur (or recur). Given other, more superior options, we avoid skin-only closure, whenever possible.

Adjunctive fascial traction — Adjunctive fascial traction techniques help pull the fascia to the midline and may improve primary fascial closure [1,27-30]. However, care should be taken to minimize excessive fascial manipulation and tension, which can result in fascial injury or creation of intra-abdominal hypertension. Fascial traction techniques include:

●Vessel loops placing traction on the skin (picture 7)

●Commercial fascial closure systems (eg, Abdominal Re-approximation and Anchor System [ABRA]) [47-49]

●Wittman patch or other mesh-mediated fascia tension (see 'Patch techniques' above)

●Fascial tension sutures (ie, retention sutures) [50,51]

●Other improvised, noncommercial fascial tension devices

●Primary fascial release (relaxing incisions of the fascia of the oblique musculature)

Fascial traction is usually needed to supplement the forces delivered by commercial negative pressure systems. A systematic review from the Eastern Association for the Surgery of Trauma (EAST) identified four trials [52-55] comparing fascial traction with or without negative pressure techniques or negative pressure techniques alone [28]. Failure of primary fascial closure during the index admission was significantly reduced with the use of fascial traction (19.7 versus 40.1 percent; relative risk [RR] 0.48, 95% CI 0.26-0.87). Among studies that evaluated ventral hernia, the rate was lower for fascial traction (9.8 versus 45.4 percent; RR 0.11, 95% CI 0.06-0.19). Fascial traction techniques did not increase the risk of enterocutaneous fistula formation or mortality.

Ostomy interference — Ostomies often interfere with the placement of temporary abdominal closure devices and, as a result, reduce the rates of primary fascial closure or functional closure.

A stoma that is matured (opening the blind end of the bowel and suturing to the skin) through the rectus muscle interferes with the placement and function of temporary abdominal closure dressings. Conversely, the abdominal dressing can prevent the proper placement and seal of the stoma appliance, leading to leakage of bowel contents onto the open wound.

To avoid these problems, whenever an ileostomy or colostomy is needed in conjunction with an open abdomen, we prefer to bring the small bowel or colon through the abdominal wall lateral to the rectus abdominis muscle through the oblique muscles, even though the incidence of parastomal hernia may be greater using this placement. (See "Parastomal hernia".)

If externalization of the colon through the abdominal wall can be delayed for a short period of time (on the order of days), temporary closure tends to be easier and a primary closure or a functional closure is more likely. The colostomy can then be created at the same time the abdominal wall is closed – similar to an elective operation.

CARE OF THE PATIENT — Following temporary abdominal closure, the patient is monitored in the intensive care unit. Abdominal dressings associated with the closure (adhesive dressings, gauze, negative pressure systems) are changed as needed and the abdominal contents inspected every two to three days in the intensive care unit or operating room, depending upon the condition of the patient and indication for the open abdomen. Dressings and abdominal inspections are continued until abdominal closure is feasible and safe.

Excessive fluid administration, particularly crystalloid-based fluids, will hinder fascial closure by contributing to visceral edema [56]. The optimal fluid resuscitation strategy minimizes net fluid administration and may possibly include the use of colloid or hypertonic solutions, which may minimize interstitial and bowel edema. One retrospective review found a significant decrease in time to fascial closure in patients who received 3% hypertonic saline rather than isotonic crystalloids as their maintenance fluid [57]. Although diuretics can reduce intravascular volume, they do not expedite fascial closure, probably due to a slower mobilization of fluid from the interstitial space to the vascular space following damage control surgery [58].

In experimental studies in animals, as well as clinical studies in humans, instillation of a 2.5% glucose, hypertonic peritoneal dialysate fluid into the open peritoneal cavity is associated with improved splanchnic and hepatic blood flow, decreased bowel edema, and improved time to, and success of, abdominal fascial closure [59-61]. Such a strategy has been termed "direct peritoneal resuscitation" or "DPR." However, randomized trials confirming these results are lacking, and there is no set protocol on how to institute or deliver this therapy. Protocols in available studies have used an 800 mL bolus of fluid followed by a continuous lavage system at 400 mL/hour until abdominal closure, and a 400 mL bolus followed by continuous lavage at 1.5 mL/kg/hour until abdominal closure. Commercial manufacturers of temporary abdominal closure devices are currently working on standardizing DPR.

Many patients remain intubated due to the severity of illness that led to the need for the open abdomen; however, the presence of an open abdomen does not mandate mechanical ventilation [62]. If the patient needs to return to the operating room for a second-look, washout, or other surgical procedure, the decision to have the patient remain intubated in the interim or to extubate the patient depends on multiple factors (eg, comorbidities, associated injuries).

The intubated patient with an open abdomen does not need to be deeply sedated or paralyzed; spontaneous breathing on the ventilator can be allowed. Light sedation (Richmond Agitation-Sedation Scale [RASS] score between -2 to 0 (table 1)) should be sufficient to keep the temporary abdominal dressing in place and prevent evisceration [63]. However, forceful Valsalva efforts, as can occur with severe agitation or delirium, may disrupt a temporary abdominal closure, potentially leading to evisceration. These patients may need to be more deeply sedated to maintain the dressings. Once the patient no longer requires frequent operative intervention, the patient can be weaned from the ventilator. (See "Sedative-analgesia in ventilated adults: Management strategies, agent selection, monitoring, and withdrawal".)

Early mobilization of critically ill patients improves outcomes, but mobilizing a patient with an open abdomen has been untested. Anecdotally speaking, mobilization of the patient must be balanced with the risk of disrupting the temporary dressing. Unlike negative pressure wound dressings elsewhere, a temporary abdominal closure dressing that becomes disrupted can result in evisceration necessitating immediate revision of the dressing and potential injury to the bowel.

The patient is returned to the operating room, typically every two to three days. There are no data to support a specific interval, and every clinical situation is different. A shorter interval between operative interventions may be physiologically challenging for the patient, whereas longer intervals may allow the formation of adhesions increasing the risk of bowel injury. Methods to limit the severity of adhesions are discussed elsewhere; however, a randomized trial found that implantation of a hyaluronate-based adhesion barrier significantly decreased the degree and tenacity of adhesions in patients who required five or more take-back operations prior to definitive abdominal wall closure [64]. The same study also found that the probability of developing dense adhesions differed significantly between the two arms nine days following initial operation. The study did not find any difference in probability of obtaining fascial closure, method of closure used, or other wound characteristics between the two groups. (See "Postoperative peritoneal adhesions in adults and their prevention".)

Assuming no contraindications (eg, ileus), enteral nutrition is permissible with an open abdomen and temporary abdominal closure dressings [65]. However, the need for repeated return to the operating room frequently leads to holding tube feeds, and nutritional goals may not be met. Under these circumstances, a combination of enteral and parenteral nutrition may be needed. Use of a volume-based, as opposed to rate-based, strategy to administer tube feeds may improve daily delivery of prescribed calories [66]. This strategy mandates that patients receive a fixed volume of tube feeds per day, thereby allowing the rate to increase for the hours in which a patient's feeds are held.

Regardless of the method used to obtain temporary abdominal closure, the ongoing loss of peritoneal fluid is associated with a net loss of protein. The protein content of peritoneal fluid is approximately 2 g/L [67]. Because the total daily volume of fluid removed can be over 1 L, the net loss of protein per day can lead to protein-calorie malnutrition. Thus, the amount of protein-based calories provided to patients with an open abdomen should be increased to take this loss into account. (See "Overview of perioperative nutrition support".)

ABDOMINAL CLOSURE

Fascial closure techniques — Ideal management of the open abdomen results in closure that brings the edges of the abdominal fascia together primarily (primary closure). If this is not feasible, functional closure or simple coverage can be provided.

Primary fascial closure — Primary closure of the fascia refers to the direct approximation of the fascial edges to each other and is associated with the lowest rate of complications following management of the open abdomen. However, the late incidence of ventral hernia following primary fascial closure for open abdomen can be as high as 30 percent [68].

Because of the high hernia rate, biologic mesh reinforcement during primary fascial closure is sometimes used. When used, it is most often placed as an underlay, although an inlay (or "bridge") may be needed when primary fascial apposition cannot be obtained. Permanent mesh is contraindicated if there are risk factors for mesh infection (eg, wound soilage). A component separation of the abdominal wall layers can also be used to provide fascial apposition [69-71]. Techniques for ventral hernia repair are discussed elsewhere. (See "Overview of abdominal wall hernias in adults" and "Overview of component separation".)

Functional closure — Functional closure refers to the bridging of a residual fascial defect with a biologic mesh (inlay technique). The biologic mesh serves as a scaffold that is repopulated with host cells, which creates new native fascial tissue [72-74]. Once the biologic mesh is placed, the skin is closed over surgical drains placed into the subcutaneous space. Functional closure is not recommended if the skin cannot be closed over the biologic mesh layer, because exposed mesh is at risk for accelerated degradation and infection until a granulation tissue layer forms over the biologic mesh, which is a slow process that can take weeks.

The late incidence of ventral hernia for functional abdominal closure to manage open abdomen has not been determined. One study that used acellular dermal matrix for ventral hernia repair noted an 80 percent hernia incidence over a mean follow-up of 21.4 months [75].

In a review of 37 patients, abdominal closure using a human acellular dermal matrix was possible in all patients who had an open abdomen for damage control indications [76]. These authors noted no complications when closure was performed "early"; early was not defined directly by the authors, but the mean duration of open abdomen in this study was 21 days.

Planned ventral hernia — If primary fascial closure or functional closure cannot be achieved, then planned ventral hernia is the only option. Skin coverage over abdominal viscera can be accomplished in one of two ways:

●Skin-only closure – A skin-only closure approximates the skin over the fascial defect, leaving a ventral hernia. Primary skin closure requires close observation to watch for wound disruption that might lead to evisceration. Skin-only closure may also be associated with an increased rate of surgical site infection associated with the use of damage control techniques [77]. (See "Principles of abdominal wall closure", section on 'Skin'.)

●Split-thickness skin graft – If the skin cannot be approximated, the viscera within the wound are allowed to adhere to each other and to the abdominal wall. Once the abdominal contents have "solidified" and there is a healthy bed of granulation tissue overlying the bowel (picture 8), a split-thickness skin graft can be placed (picture 1) [78]. Occasionally, an absorbable (eg, Vicryl) mesh is sutured to the skin to prevent evisceration while awaiting granulation. Before elective hernia repair is attempted, 6 to 12 months are generally allowed to elapse following placement of a split-thickness skin graft. The interval of time allows maturation and dissolution of abdominal adhesions with a lower incidence of enterotomy during hernia repair [79].

Timing of closure — Early fascial closure, rather than later closure, appears to be important for providing the best functional outcome in the long term [80,81]. In a study that compared early closure (<7 days) versus late closure (>7 days), those in the early group had less daily pain, better quality-of-life scores, and were more likely to return to work (54 versus 10 percent) [80]. In a review of 499 patients, primary fascial closure occurred in 327 patients (65.5 percent). Increasing time to the first take-back was associated with a decreased likelihood of primary fascial closure [81]. Each hour delay after 24 hours was associated with a 1.1 percent decrease in the chance for primary closure. In addition, there was a trend toward increased intra-abdominal complications in patients returning after 48 hours. Although these studies were not randomized and the results may be due to self-selection, earlier rather than later closure of the abdominal wall is the goal.

Each time the patient is returned to the operating room, the abdomen should be assessed for potential closure. If closure cannot be performed, the temporary abdominal closure dressing is replaced with the fascial edges brought together as closely as possible and a return to the operating room planned in another 48 hours. In a review of 344 trauma patients with an open abdomen for damage control, abdominal fascial closure was achieved in 63 percent of the patients at the second-look procedure [23]. The need for ongoing fluid resuscitation or the development of a systemic inflammatory response will delay the time for fascial approximation [82-84]. Fascial closure may not be possible under these circumstances. Generally speaking, the longer the abdomen remains open, the less likely primary fascial or functional closure will be achieved. With time, the fascia retracts further from the midline and the underlying bowel becomes adherent to the peritoneal cavity. Complications also increase as the interval from initial operative intervention to attempted closure increases [23]. (See 'Complications of open abdomen' above.)

If fascial closure is repeatedly unsuccessful, functional closure or intentional hernia with abdominal wall coverage can be used instead at any point in time. (See 'Functional closure' above and 'Planned ventral hernia' above.)

Rates of primary fascial closure — Systematic reviews have identified a few small randomized trials [52,53,85-88] and other retrospective studies reporting rates of primary fascial closure and complication rates for the various temporary abdominal closure techniques described above [1,68,89-93]. Risk factors independently associated with a risk for failure to achieve primary fascial closure during initial hospitalization in a study of 572 patients from 14 Level I trauma centers included increased number of re-explorations, intra-abdominal abscess/sepsis, enteric fistula, and Injury Severity Score (ISS) of greater than 15 [94]. In another study of nontrauma patients, peritonitis or the presence of a stoma increased the risk for failure of primary closure [95].

In one systematic review that included 74 studies, the overall rate of fascial closure ranged from 34 to 74 percent [1]. The risk for fistula formation ranged from 2.2 and 29.5 percent. Mortality in the mixed populations of patients requiring open abdominal management was between 11 and 39 percent.

In another review, representative mean rates for primary fascial closure are as follows [91]:

●90 percent: Wittmann Patch (4 studies/180 patients)

●85 percent: Dynamic fascial closure (1 study/15 patients)

●60 percent: Sponge-based negative pressure system (8 studies/251 patients)

●52 percent: Towel-based negative pressure system (15 studies/1186 patients)

●29 percent: Silo technique (3 studies/109 patients)

Two other small studies have reviewed the use of the Wittmann Patch, finding primary fascial closure rates of 78 and 82 percent [33,96]. Although the Wittmann Patch has the highest average rate of primary fascial closure compared with other techniques, this temporary closure technique, when used alone, does not adequately manage fluid loss. (See 'Patch techniques' above.)

Some studies have reported rates for primary fascial closure using negative pressure systems that are higher than those reported in the systematic review above; however, rates range widely from 22 to 91 percent, reflecting heterogeneity in the study populations as well as methodology [1,92]. As an example, a retrospective review evaluating 104 patients found significantly higher primary fascial closure rates for negative pressure (vacuum-assisted) systems compared with those that provided no form of abdominal tension (78 versus 44 percent) [97]. In the above systematic review, the addition of fascial traction via mesh or sutures (six studies) increased the closure rates associated with negative pressure wound therapy to 73 percent (range 63 to 81 percent) compared with negative pressure therapy alone at 52 percent (range 47 to 56 percent; 32 studies) [1].

Another study, a multicenter, prospective, observational study (NCT01016353) involving 280 patients at 20 sites, compared towel-based (Barker, 102 patients) and sponge-based (AbThera, 178 patients) techniques [31]. Demographic and initial disease severity variables were similar between the groups. The 30 day primary fascial closure rate was significantly lower for the towel-based system (51 versus 69 percent) among patients who required open abdominal management ≥48 hours. All-cause 30 day mortality was also significantly higher for the towel-based group (30 versus 14 percent), potentially related to increased fluid resuscitation requirements and development of multiorgan dysfunction in this group in spite of initially similar disease severity. This is the first study to suggest a difference in survival between two differing temporary abdominal closure techniques. The authors speculate that the sponge-based system may be more efficient at removing fluid, rich in inflammatory cytokines, from the abdomen. Further study will be needed to confirm these data.

Studies evaluating dynamic fascial closure with or without other techniques reported primary closure rates of 61 to 91 percent [98-100]. In a multicenter study of 111 patients requiring long-term management for open abdomen (>5 days), and managed with sponge-based negative pressure and mesh-mediated fascial traction, primary fascial closure was achieved in 69 percent of patients [101].

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 compartment syndrome" and "Society guideline links: Abdominal incisions and closure".)

SUMMARY AND RECOMMENDATIONS

●The term "open abdomen" refers to a defect in the abdominal wall that exposes the abdominal viscera. Open abdomen is often created intentionally by leaving an abdominal incision open at the completion of surgery or by opening (or reopening) the abdomen because of abdominal compartment syndrome. (See 'Introduction' above and 'Open abdomen' above.)

●Open abdomen leads to fluid and protein losses. With prolonged open abdomen, bowel fistulization and loss of abdominal domain can complicate management. The main goal of temporary abdominal closure techniques is to control fluid losses and minimize the loss of domain. (See 'Complications of open abdomen' above.)

●Several techniques for temporary abdominal closure are available, including patch closure, negative pressure systems (towel and sponge based), and silo closure. Each technique has advantages and disadvantages with respect to its ability to control fluid loss, frequency of dressing changes, minimizing loss of domain, ease of use, and cost. (See 'Techniques' above.)

●Following temporary abdominal closure, the patient is monitored in the intensive care unit. Abdominal dressings associated with the closure (adhesive dressings, gauze, negative pressure systems) are changed as needed and the abdominal contents inspected every two to three days in the intensive care unit or operating room, depending upon the condition of the patient and indication for the open abdomen. Dressings and abdominal inspections are continued until abdominal closure is feasible and safe. (See 'Care of the patient' above.)

●The Wittmann Patch has the highest average rate of primary fascial closure compared with other techniques in observational studies. However, this temporary closure technique, when used alone, does not adequately manage fluid loss. (See 'Rates of primary fascial closure' above.)

●We suggest using a negative pressure system (sponge or towel based) to control and quantify fluid loss (Grade 2C). Negative pressure systems can be used alone or in conjunction with other temporary abdominal closure techniques. Although the applied negative pressure counteracts some of the lateral forces responsible for loss of abdominal domain, additional adjunctive techniques may be needed to help bring the fascial edges to the midline to improve the rates of primary closure. (See 'Negative pressure wound systems' above.)

●Once the indication for the open abdomen has resolved, the abdomen is closed, preferably with a primary fascial closure. If primary fascial closure cannot be achieved, functional closure can be performed using a biologic mesh inlay technique, which generates new fascial tissue between the native fascial edges; however, the risk of subsequent hernia with this technique is high. If the gap between the fascial edges is too wide for a functional closure, primary skin closure can be performed or skin grafts placed to cover the fascial defect once a layer of granulation tissue has developed over the consolidated visceral mass. (See 'Fascial closure techniques' above.)