INTRODUCTION — The management of leaks and perforations of the gastrointestinal (GI) tract has been a burden for surgeons. This is especially difficult in the esophagus and rectum because of high morbidity and mortality rates. (See "Overview of gastrointestinal tract perforation".)
In the past, these cases have been managed primarily by surgical intervention; however, the evolution of alternative therapies such as endoscopic stent placement provides a less invasive method for control. Unfortunately, these less invasive therapies do not always succeed. As a result, other minimally invasive options to control leaks and perforations have been developed.
Negative pressure wound therapy has long been a treatment of choice for complex external wounds [1]. As the need for further options to control GI leaks has increased, it has been adapted for internal use. This has led to the development of endoluminal vacuum therapy (EVAC), which can be utilized to both avoid damage control surgeries as well as reduce morbidity and mortality rates. EVAC is still in its infancy, but the progress for its utilization is growing around the world. (See "Negative pressure wound therapy".)
This topic will cover the patient selection, technique, postoperative care, and outcomes of EVAC.
DEVICE AND PLACEMENT — Endoluminal vacuum therapy (EVAC) delivers negative pressure to a leak site in the gastrointestinal (GI) tract through a nasogastric tube (NGT) terminating at a polyurethane sponge, termed endosponge (picture 1). The endosponge has the ability to collapse the cavity and create a seal. The endosponge is delivered to the leak site endoscopically and placed in one of two ways:
●Intracavitary – The endosponge is placed in the leak cavity, outside of the mucosa-lined space.
●Intraluminal – The endosponge is placed within the GI tract on the mucosa and completely covers the leak site. The endosponge will seal off the leak by adhering to the adjacent mucosa.
The pioneers of EVAC used a homemade device constructed from readily available GranuFoam dressing connected to a source of negative pressure (eg, Redovac) by an NGT. A manufactured device named endo-SPONGE is available in part of Europe [2-4].
EVAC should be performed by an endoscopist with extensive interventional endoscopic experience. This can be either a surgeon or gastroenterologist. One study demonstrated an average time for the procedure at 43 minutes and that proficiency for the procedure plateaued with respect to time at 10 procedures [5]. The same study indicated that procedures can be done in the operating room or the endoscopy suite, but the endoscopy suite cost was much lower. However, with critically ill patients, the operating venue should be chosen based on optimal patient care and safety rather than cost.
MECHANISM OF ACTION — Endoluminal vacuum therapy (EVAC) has multiple benefits to aid in the healing of leaks and perforations of the gastrointestinal (GI) tract [6]:
●First, it is able to obtain and maintain source control. Intracavitary or intraluminal placement of the endosponge at a leak site allows for collapse and containment once negative pressure is applied.
●Second, adjacent tissue is pulled into the pores of the endosponge during active therapy. When the endosponge is removed, this causes debridement and eventual decontamination of the affected tissue.
●Lastly, use of EVAC encourages tissue reperfusion, encouraging eventual healing of a leak. Over time, the goal of therapy is for the cavity to contract and to reestablish continuity of the GI tract.
PATIENT SELECTION — Once the diagnosis of a gastrointestinal (GI) tract leak has been made, the patient's clinical stability should be assessed first. Clinical instability is considered a relative contraindication to endoluminal vacuum therapy (EVAC) and should result in damage control surgery at the discretion of the surgeon. Although EVAC has been used in cases of septic shock and hemodynamic instability, this should be performed by an experienced surgeon/endoscopist and/or reserved for patients who are nonsurgical candidates or refuse surgery [7].
Indications
●Ongoing leak in the GI tract. Leaks most commonly treated with EVAC are postoperative anastomotic leaks (esophageal or colorectal) or gastric sleeve leaks (bariatric). Leaks or perforations of other etiologies (eg, iatrogenic) are also amenable to EVAC. (See 'Outcomes of EVAC' below.)
●Leak site accessible by an endoscope.
Absolute contraindications
●A leak or cavity that connects to the atmosphere (eg, enterocutaneous fistula). EVAC placed for such leaks will not be able to maintain a seal, which is required for source control. (See "Enterocutaneous and enteroatmospheric fistulas".)
●Visible vessel near or touching the endosponge.
●Patient inability to return at regular intervals for endosponge exchange. (See 'Step 5: Retrieval/exchange of the endosponge' below.)
Relative contraindications
●Clinical instability. In general, clinically unstable patients (eg, septic, hypotensive, rigid abdomen) should be treated surgically. EVAC should only be attempted in such patients by an experienced endoscopist/surgeon and/or when the patient is not a surgical candidate or refuses surgery (palliation).
●Large (>3 cm) mucosal defects. Larger defects are challenging for EVAC because the size of endosponge that can be inserted is limited by the luminal diameter of the esophagus or anus [7]. An undersized endosponge that does not occlude the defect will not achieve source control. However, an experienced endoscopist could potentially use a narrow but longer endosponge to seal off a large defect.
●Chronic leaks (>4 to 6 weeks from initial surgery or leak). The success rate of EVAC decreases with increasing chronicity of the leak. The best result is achieved when EVAC is initiated within four to six weeks of the initial leak in the peritoneal cavity [8,9]. We treat chronic leaks surgically either immediately or after planned two-week EVAC therapy for debridement and source control [7].
●Lack of proximal fecal diversion (for colorectal leaks). This is a risk factor for EVAC failure because continued passage of stool, luminal fluid, and air contaminates and obstructs the endosponge and disrupts the negative pressure suction in the cavity [10]. Patients who already have fecal diversion from the initial operation are ideal candidates for EVAC if they develop a leak since EVAC can be performed without another operation. Indeed, in a meta-analysis of 276 patients treated with EVAC, 94 percent of the fecal diversions were performed during the initial operation [10].
●Leak or cavity site difficult to access endoscopically. Leaks that are inaccessible to endoscopy (eg, certain small bowel leaks) are excluded from EVAC. Additionally, certain leak sites in the foregut and hindgut may be technically accessible but difficult to access given their positions in relation to the endoscope within the lumen of the GI tract. As an example, a leak just beyond the gastroesophageal junction on the gastric side is very difficult to access because it requires the endoscope to be in a retroflexed position for placement and removal of the endosponge. A rendezvous technique has been developed, which uses the endoscope to pull the endosponge into position via an alternate access (eg, gastrostomy tube or percutaneous drain tract) other than a natural orifice such as the mouth [11,12].
Usage of other endoscopic modalities or prior surgical approaches to heal the leak is not a contraindication to EVAC. In other words, EVAC can be used as a primary treatment modality, in conjunction with or as a bridge to surgical therapy, or as rescue therapy after failed surgical or other endoscopic interventions [13]. EVAC should be used as a part of the armamentarium for leak management, rather than as a stand-alone treatment modality. As an example, EVAC patients who have heavy contamination in the peritoneal or pleural cavity due to free perforation may require additional drainage procedures such as percutaneous drainage or even surgery. (See 'Additional procedure to decontaminate peritoneal/pleural cavity' below.)
EVAC MANAGEMENT
Preoperative preparation — The endoluminal vacuum therapy (EVAC) procedure varies based on whether the leak is in the upper or lower gastrointestinal (GI) tract.
●For upper GI tract leaks, the procedure should be done under general anesthesia with endotracheal intubation. It is important to protect the airway given the size of the endosponge that will be passing through the oropharynx and by the larynx. Once intubation has occurred, the patient positioning is up to the endoscopist, whether supine or decubitus.
●For lower GI tract leaks, anesthesia and positioning is up to the endoscopist.
●Patients undergoing EVAC are generally already receiving broad-spectrum antibiotics for the leak or perforation.
●Although EVAC is an endoscopic procedure, it is usually performed under general anesthesia. As such, standard mechanical and pharmacologic venous thromboembolic prophylaxis should be provided per institutional protocols. (See "Prevention of venous thromboembolic disease in adult nonorthopedic surgical patients".)
Operative technique — The EVAC procedure can be divided into five steps [7]:
Step 1: Diagnostic endoscopy — Initially, the distance of the leak from the accessed orifice (mouth of anus) is noted to determine if the leak is amenable to endoscopic therapy. Once the leak is identified, the cavity is irrigated and debrided endoscopically as much as possible.
Next, additional features, including size of the perforation, level of contamination, and size of the cavity associated with the leak, must be noted (picture 2). This will determine the size of the endosponge and whether its placement will be intracavitary or intraluminal. We prefer to place the endosponge into the cavity for better debridement. However, when the size of the perforation is <1 cm, endosponges are generally placed intraluminally because the GranuFoam cannot be compressed to <8 mm [14], except that occasionally, we have enlarged the opening to deliver the endosponge into the cavity.
Step 2: Constructing the endosponge — There is no commercially available endosponge in the United States; the endosponge needs to be created by the surgeon/endoscopist. There are several ways to create it, but most reports use a polyurethane GranuFoam provided for use externally by KCI, but not the polyvinyl WhiteFoam, which does not compress as much. The GranuFoam is cut to about 6 cm in length and no larger than 3 cm in width. The width is limited by the lumen of the GI tract (anus or upper esophageal sphincter and esophageal lumen) (picture 3). The endosponge should be tailored to the size of the cavity or leak site. In parts of Europe, there is a manufactured device available called endo-SPONGE.
The endosponge is attached to tubing to provide the negative pressure externally. This is usually a nasogastric tube (NGT) of varying size. For upper GI leaks, it is essential to place the tube through the nose and pull it through the mouth prior to attaching the endosponge to allow it to function as a normal NGT. This is not necessary for lower GI tract leaks. The endosponge is secured to the tubing with a strong permanent suture. Keeping the endosponge attached to the tubing is extremely important both for maintaining a continuous seal and for ease of retrieval.
A second suture is placed at the distal end of the endosponge to permit an endoscopic grasper to carry it through the GI tract (picture 4). This can be done with the same permanent suture and with an air knot placed through both the endosponge and the tip of the tubing for stability and strength (the NGT traverses the entire length of the endosponge in a tunnel made with scissors).
The air-sump port in the NGT should be occluded to allow for a complete seal. This can be accomplished by reversing the sump valve or simply occluding the port with tape.
Step 3: Endoscopic placement of the endosponge — The endoscope is used to carry the endosponge through the GI tract with a rat tooth grasper placed through the working channel of the endoscope grasping the air knot suture. Once the desired location is reached (picture 5), the suture securing the endosponge is released from the grasper under direct visualization. Negative pressure should only be applied after the endosponge has been placed at the ideal location (detailed in next step). Once the negative pressure is applied, the endoscope is removed gently. Pulling the endoscope prior to that may dislodge or displace the endosponge into the wrong location. Prior to removing the endoscope completely from the mouth, one should ascertain that there is no coiled tubing in the oropharynx. The NGT is then secured to the nose or nasal septum with a bridle or tape.
Step 4: Application of negative pressure — Since there is no specific device to provide negative pressure for EVAC, a portable device such as the KCI wound VAC system is commonly used. Adapting the tubing to the negative pressure device should be done in a closed system. No definitive recommendations have been made for pressure, but continuous pressure settings between 125 and 175 mmHg seem appropriate.
Step 5: Retrieval/exchange of the endosponge — Like other external wound dressings, the endosponge needs to be changed frequently. The ideal interval for exchange is still a matter of ongoing research, but reports recommend somewhere between three and five days. This leaves the endosponge in place long enough to provide a reasonable interval break from procedures but short enough to prevent too much tissue ingrowth into the endosponge.
Removal of an endosponge should be done under endoscopic vision. The endoscope itself is used to dislodge the granulation tissue circumferentially at the tissue/endosponge interface. Pulling on the NGT without such a step may disconnect the NGT from the endosponge and make retrieval of the latter much more difficult.
EVAC therapy is finished when the leak site is completely sealed. This means that luminal contents will remain within the lumen lined with either epithelium or granulation tissue without leaking into other tracts, sinuses, or fistulas, and there is no further contamination. Endoscopically, the leak site will appear as a shallow wound bed with possibly a small amount of outpouching, but the continuity of the GI tract has been reestablished (picture 6). The length of EVAC use varies with the organ system and is also affected by the length of time the patient has had the leak [15]. (See 'Outcomes of EVAC' below.)
POSTOPERATIVE CARE — Patients are usually kept in the hospital for the duration of the endoluminal vacuum therapy (EVAC) treatment. Postoperative care includes endoscopic reevaluation/endosponge change at regular intervals, ongoing nutritional support, and drainage of the peritoneal or pleural space (when necessary).
Additional procedure to decontaminate peritoneal/pleural cavity — Although EVAC is capable of achieving source control in most, if not all, patients, those with free perforation into the peritoneal or pleural cavity may have already incurred significant contamination of those spaces that cannot be fully debrided by EVAC alone. Such patients may require additional procedures, such as percutaneous drainage by interventional radiology, or even surgery to wash out the peritoneum or pleural space [7]. Such procedures can be performed before or after the initiation of EVAC at the discretion of the endoscopist/surgeon. Once source control is secured internally by EVAC, the peritoneal/pleural drains should be removed to promote healing.
Nutritional support — Wound healing ultimately depends on nutritional support, although the optimal approach varies between upper and lower gastrointestinal (GI) tract leaks.
Patients with upper GI tract leaks cannot tolerate oral nutrition; nutritional supplementation during EVAC therapy relies upon total parenteral nutrition (TPN) or tube feeds. Tube feeds should be administered to the small bowel via an extension gastrojejunostomy tube or a surgically placed jejunostomy tube. Gastric tube feeds can be pulled into the endosponge by the negative pressure, causing it to clog or contaminate the area. Percutaneous endoscopic gastrostomy (PEG) tube placement is contraindicated in the presence of an esophageal or gastric leak. A nutritionist should be following the patient care as tube feedings are often held for repeated endoscopic procedures.
Patients with lower GI tract leaks can take normal oral nutrition, but the patient needs to have a diverting stoma proximal to the leak site. Luminal flow of the fecal contents will disrupt the function of the endosponge, causing it to be dislodged and malfunction. The stoma can be reversed shortly after (within one month of) healing. EVAC has been credited with a higher rate of stoma reversal than other techniques of leak control.
Staff education — At most hospitals, EVAC is still a new procedure, and as such, equipment can be mishandled by staff not trained in its intended use. Measures must be taken to ensure that the nasogastric tube (NGT) used for EVAC is not used for tube feeds or medication administration. Also, the negative pressure application needs to be continuous rather than intermittent. Nursing staff should also avoid disconnecting the tubing or turning off therapy when patient is mobilizing.
OUTCOMES OF EVAC — Although numerous case reports or case series have demonstrated the effectiveness of endoluminal vacuum therapy (EVAC), there have been no randomized trials for EVAC, nor are there many large systematic reviews. This is likely due to the drastic heterogeneity in the type of leaks, affected organs, patient management, time to leak recognition, and evolving techniques. Currently, EVAC is most commonly used to treat esophageal anastomotic leaks, gastric leaks after bariatric surgery (sleeve gastrectomy), and colorectal anastomotic leaks.
Colorectal — In 2003, EVAC was first used in the rectum by Weidenhagen to heal anastomotic leaks after rectal resection and Hartmann's stump leaks [8]. Since then, EVAC has been used for colorectal or coloanal anastomotic leaks with reported healing rates consistently above 80 percent. This usually requires a hospital stay of 20 to 45 days and six to seven endoscopic procedures. A diverting stoma is helpful but not always required. Several overlapping systematic reviews reported these results, which should be interpreted cautiously due to the significant heterogeneity of the studies included [10,16,17].
A large multicenter French study of 47 patients found that colorectal or coloanal anastomotic leaks treated with EVAC within the first two weeks healed at a higher rate than leaks treated later (72.4 versus 27.8 percent) [18]. Additionally, the use of EVAC for a duration longer than three weeks was associated with a lower healing rate (33 versus 69 percent). Lastly, patients with a diverting stoma (38 patients) had the same healing rate (both 55 percent) as those without a stoma (9 patients).
A study of 18 patients with leak after rectal cancer resection (88 percent had neoadjuvant therapy) demonstrated an 83 percent healing rate [19]. Forty-four percent had a primary protective ileostomy. There was a 16 day delay from sentinel surgery to leak detection where EVAC could be started. An average of 6 endosponge changes were needed over 22 days (4 to 43 days).
Another study of 56 patients showed similar outcomes with rectal stump leaks [20]. The healing rate was 84 percent with a median duration of 20 days and median of 7 endosponge exchanges.
Esophagus — Given the feasibility and success with using EVAC in the rectum, it was next adapted to treating anastomotic leaks of the esophagus by Loske [21-23] and Wedemeyer [24].
Currently, EVAC is most frequently used to manage esophageal leaks among all organ systems. The largest esophageal experience was reported in 2017 with 77 patients and a 78 percent closure rate [25]. In a review of 29 studies with a total of 209 patients, the range of healing rates with EVAC was 67 to 100 percent; anastomotic stricture was the most frequent long-term complication (9 percent) [26]. EVAC has been used as primary therapy or rescue therapy after failed surgical repairs [13]. Alternatively, it can be used as a bridge to definitive surgical repair in patients with large defects (loss of domain) but very little surrounding tissue to collapse upon, such as with esophago-bronchial or esophago-trachea fistulas.
Given these positive results, endoscopists have used EVAC prophylactically to avoid potential leaks in high-risk esophageal anastomoses. The endosponge is removed after four to six days and the anastomosis is evaluated; EVAC is continued until there are no longer any worrisome features at the anastomosis. In two studies of 19 and 67 patients, the use of prophylactic EVAC resulted in a 5 to 7.5 percent leak rate [27,28], lower than the approximately 10 percent leak rate reported by large studies of esophagectomies without EVAC [29].
Stomach — The first cases of gastric leaks treated with EVAC were reported in 2015; one staple line leak and one iatrogenic injury were successfully healed with EVAC [30].
Currently, EVAC is most commonly used to treat gastric leaks from bariatric surgery (eg, sleeve gastrectomy and gastric bypass). The first cases of use in sleeve gastrectomy leaks were reported in 2015, documenting nine cases where eight (89 percent) were healed successfully with EVAC over a mean of 51 days [31]. This study was later followed up with 17 patients and a healing rate of 82 percent over a mean of 56 days [15], then again for 24 patients with a 79 percent heal rate over a mean of 44 days [7]. There was a study of six patients in Germany where a 100 percent heal rate was reported after a median of 24 days [32].
There have been few reports of EVAC use in nonbariatric cases, but one patient healed a leak at the gastrojejunostomy in 49 days [15]. There is also report of three out of three gastric perforations healing with EVAC after a mean of 30 days [15].
Duodenum and small bowel — EVAC was first used to treat a duodenal leak in a patient who had a duodenojejunal anastomosis [33]. Shortly after, EVAC was used to treat an infected pancreatic pseudocyst [34], a leak following pancreaticoduodenectomy [35], and a pancreaticogastric anastomosis [36]. The first report in the United States included three cases of duodenum or small bowel leaks, all of which healed with EVAC [15].
Adverse events and failure — There are very few reported adverse events for EVAC. Importantly, there have been no reports of endosponge eroding into adjacent organs (hollow viscus or blood vessels) in the literature.
EVAC has failed when [7]:
●Source control has been lost. Typically the patient would become unstable, prompting reevaluation and definitive surgical intervention.
●There is failure to progress. With EVAC, patients are typically examined endoscopically twice a week. If the wound fails to continue to debride, contract, and revascularize, surgical intervention is also required.
EVAC VERSUS OTHER THERAPIES FOR LEAKS — In contemporary practice, gastrointestinal (GI) leaks and perforations can be managed by surgical diversion, primary repair, and endoscopic techniques such as fibrin glue, clipping, stenting, and endoluminal vacuum therapy (EVAC).
EVAC has been compared with stenting in healing anastomotic leaks following esophagectomy. In one study, the mean duration of EVAC (25 patients) was 44 days, and endosponges were changed a mean of 7.4 times. The stent group (13 patients) had a mean duration of therapy of 30 days, and the stents were changed 1.5 times over 0.8 endoscopic procedures. Length of stay was significantly shorter in the stent group [37]. Several meta-analyses of patients with anastomotic leaks from either esophagectomy or total gastrectomy associated EVAC with a higher fistula closure rate and lower mortality rate compared with endoscopic stenting [38].
The overall costs of EVAC versus stenting do not differ statistically, because the intensive care unit stay is responsible for most of the cost when managing leaks after esophagectomy [37]. Another study on cost looked to justify EVAC based on the lower cost of an endoscopy suite compared with an operating room [5].
For sleeve gastrectomy staple line leaks, one study of 27 patients reported a healing rate of 86 percent for EVAC versus 39 percent for stent [39]. Additionally, patients treated with EVAC had shorter treatment duration and lower adverse events rates.
For colorectal leaks, EVAC can be applied regardless of the level of the anastomosis and size of the abscess cavity, whereas stent insertion is contraindicated in low anastomotic leaks due to patient discomfort and potential for stent migration and can only treat abscesses <2 cm. Fibrin glue is limited to treating leaks <3 mm in diameter without any associated abscess [40]. (See "Enteral stents for the management of malignant colorectal obstruction", section on 'Adverse events'.)
Nevertheless, the best technique, whether endoscopic or surgical, is selected based on the size and location of the leak as well as the condition of the patient. Furthermore, various techniques may be used in tandem, rather than in isolation, to heal GI leaks or perforations and limit potential complications.
SUMMARY AND RECOMMENDATIONS — Endoluminal vacuum therapy (EVAC) is a minimally invasive method of managing leaks and perforations of the gastrointestinal (GI) tract. Currently, EVAC is most commonly used to treat esophageal anastomotic leaks, gastric leaks after bariatric surgery (sleeve gastrectomy), and colorectal anastomotic leaks. (See 'Outcomes of EVAC' above.)
●EVAC delivers negative pressure to a leak site in the GI tract through a nasogastric tube (NGT) terminating at a polyurethane GranuFoam sponge, termed endosponge. The endosponge is delivered to the site of the leak endoscopically and can be placed outside (intracavitary) or inside (intraluminal) the GI lumen. (See 'Introduction' above and 'Device and placement' above.)
●EVAC promotes healing of leaks/perforations of the GI tract by maintaining source control, debriding wounds, and encouraging tissue reperfusion. (See 'Mechanism of action' above.)
●Once the diagnosis of a GI tract leak has been made, the first step is to assess the patient's clinical stability. For most patients who are clinically unstable (eg, hypotensive, septic, rigid abdomen), we suggest treating the leak surgically, rather than with EVAC (Grade 2C). Although EVAC has been used in cases of septic shock and hemodynamic instability, this should be reserved for an experienced surgeon/endoscopist and/or when the patient is not a surgical candidate or refuses surgery. (See 'Relative contraindications' above.)
●In theory, EVAC can be used to treat any ongoing leak in the GI tract that is accessible to endoscopy. EVAC is contraindicated when the cavity connects to the atmosphere (eg, enterocutaneous fistula), when there is visible vessel nearby, or when there is a lack of reliable follow-up. However, defect size >3 cm, chronic leak >4 to 6 weeks, absence of a proximal diverting stoma (in colorectal leaks), and certain unfavorable locations of the leak/cavity may make EVAC difficult or reduce the success rate. (See 'Patient selection' above.)
●The steps of EVAC include diagnostic endoscopy to find the leak and note its characteristics, construction of the appropriate endosponge, endoscopic placement of the endosponge, application of negative pressure, and endosponge retrieval/exchange. (See 'Operative technique' above.)
●We generally place an intracavitary endosponge when the leak is ≥1 cm in size and place an intraluminal endosponge when the leak is <1 cm. Leaks >3 cm in size are difficult to heal with EVAC and therefore are better treated surgically. (See 'Step 3: Endoscopic placement of the endosponge' above.)
●For patients who incur significant contamination of the peritoneal/pleural cavity before EVAC achieves source control, additional procedures (eg, percutaneous drainage or surgical washout) may be necessary to decontaminate those spaces. (See 'Additional procedure to decontaminate peritoneal/pleural cavity' above.)
●Patients undergoing EVAC for an esophageal or gastric leak require total parenteral nutrition or tube feeds. Tube feeds should be administered to the small intestine via an extension gastrojejunostomy tube or a surgically placed jejunostomy tube as tube feeds present in the stomach can be pulled into the endosponge by the negative pressure, causing it to clog or contaminate the area. (See 'Nutritional support' above.)
●Most patients undergoing EVAC for a colorectal leak require a diverting stoma proximal to the leak site. Luminal flow of the fecal contents will disrupt the function of the endosponge, causing it to be dislodged and malfunction. Stoma may be reversed shortly after the leak has healed; the stoma reversal rate after EVAC compares favorably to that of other techniques. (See 'Nutritional support' above.)
●EVAC is associated with very few reported adverse events with no reported erosion into adjacent organs. Failure of EVAC, indicated by either loss of source control or failure to progress, mandates surgical intervention. (See 'Adverse events and failure' above.)
