A leak is the egress of gastrointestinal contents through a suture or staple line into a cavity. Thus, luminal content can exit through the gastrointestinal wall freely into the peritoneal cavity or can collect next to an anastomosis or suture or staple line [8]. Gastric leak has also been described in terms of:

Gastric leaks represent one of the most dangerous complications of bariatric surgery. In the literature, the incidence of GL after LSG ranges from 0 to 7 % [9–11] (Table 2). Most leaks appear in the proximal third of the stomach, close to the gastroesophageal junction or near the angle of His. Burgos et al. [12] reported 85.7 % of leaks in the proximal third and only 14.3 % in the distal third. A.A. Saber et al. [11] analyzed 29 publications using a MEDLINE search and reported on 4,888 patient records. The mean BMI ranged from 34 to 65.4 kg/m², and all 29 studies documented a leak rate, which ranged from 0 to 7 %. The mean leak rate for all 29 studies was 2.4 %, which accounted for 115 leaks in 4,888 cases of sleeve gastrectomy. There did appear to be a higher leak rate in patients with a BMI > 50 kg/m².

Six studies specifically addressed super-obese patients with a mean BMI > 50 kg/m². In the super obese, the mean leak rate was 2.9 % or 23 leaks of 771 patients compared with the leak rate of only 2.2 % (92/4,117) for those with mean BMI < 50 kg/m² (not significant P > 0.05).

It is possible that these types of proximal leaks (i.e., those at the gastroesophageal junction or near the angle of His) have multiple different etiologies. One plausible theory is that the final staple line is placed across the gastroesophageal junction or distal esophagus causing poor staple-line configuration. Another more likely is the vascular theory. As Basso et al. explains [13], the cardias (distal esophagus and esophagogastric junction) are supplied in the right and anterior side by branches of the left gastric artery and left inferior phrenic artery. The posterior left side is vascularized mainly by fundic branches of the splenic artery and, if present, by the posterior gastric artery. The arterial supply of the esophagus is segmental. Complete dissection of the fundus requires division of the short gastric vessels, of the posterior gastric artery, and of the phrenic branches when present. A “critical area” of vascularization may occur laterally, just at the esophagogastric junction at the angle of His (Fig. 1) (Video 2).

They describe a resection line avoiding the critical area by leaving 1–2 cm of gastric remnant just at the gastroesophageal junction to avoid the area described (Fig. 2).

Nocca et al. described particular caution at this same region in those patients who had previously undergone adjustable gastric band and were undergoing conversion to sleeve gastrectomy. The concern was due to the increased fragility of gastric tissue from the fibrosis after contact with the silicone band [14]. Bellanger et al. [15] describes two basic principles for minimizing leaks. The first and most important is to avoid creating a stenosis at the level of the angular incisures, and the second (as previously described) is to avoid resection too close to the esophagus in the area of the cardia. The mid-sleeve stenosis (at the incisura) can be from a truly stenotic lumen (Fig. 3) or, more commonly, twisting or kinking of the sleeve at the incisura that causes a functional obstruction (Figs. 4 and 5). This relative downstream obstruction in the setting of a proximal leak can lead to a persistent fistula that does not resolve with conservative management. Yehoshua et al. [16] showed that high intraluminal pressure and low compliance of the gastric tube may be the main cause of leak and fistulas in this area.

Patient factors described in the literature, with a greater incidence of leak, include older age, BMI > 60 kg/m², malnutrition, and a history of laparoscopic gastric banding. Some authors distinguish between mechanical and ischemic causes of post-LSG GL. Baker et al. [17] suggest that fistulas on the staple line may have multiple causes, but these can be divided into two categories: mechanical-tissular causes and ischemic causes. In both situations, intraluminal pressure exceeds tissular and suture line resistance, thus causing the fistula. Classic ischemic fistulas tend to appear between 5 and 6 days after surgery, when the wall healing process is between the inflammation phase and fibrotic phase. When the cause is mechanical tissular, fistulas are usually discovered before this period, that is, within the first 2 days after surgery.

A high index of suspicion and early identification of leaks after LSG are critical to achieving an acceptable outcome after this complication. Unexplained tachycardia, fevers, abdominal pain, or persistent hiccups after the procedure should alert surgeons to investigate for a leak (Table 3).

The signs and symptoms of the patients who develop a leak are similar to patients with other types of abdominal infections. However the clinical presentation of gastric leak ranges from the patient being completely asymptomatic (identified by fluoroscopic study) to the presentation of peritonitis, septic shock, multiorgan failure, and death. Burgos et al. report a series of 7 leaks in 214 patients (3.3 %), of which 5 patients presented abdominal pain, fever, tachycardia, tachypnea, and increased laboratory signs of infection. They observed that tachycardia is an initial sign of early leak [12]. Casella et al. reported leaks in 3 % of 200 patients. In general, the symptomatology was abdominal pain, vomiting, and fever; only one patient was asymptomatic [19]. According to Tan et al. [20] and de Aretxabala et al. [21], early-onset GL presents with severe, sudden abdominal pain (together with fever, nausea, and vomiting), whereas delayed-onset GL is usually of a more insidious nature (with gradually increasing abdominal discomfort and fever). Patients with early-onset GL show signs of sepsis caused by gastrointestinal contents in the peritoneal cavity, and they require at least a surgical lavage and the placement of drains. For patients with delayed-onset GL, fluid frequently collects near to the stomach and does not spread to the rest of the cavity. Four clinical presentations have approximately the same frequency: systemic signs of inflammation, peritonitis, abscess, and pulmonary symptoms. Pulmonary symptoms can be caused by a subphrenic abscess (in both early- and delayed-onset GL) or complex bronchogastric fistula (delayed-onset GL). Medical and surgical teams must be aware of initial, atypical presentations or those occurring during follow-up: [1] bronchogastric fistulas (revealed by chronic cough and managed with a pulmonary lobectomy [2], acute hematemesis revealing a left gastric artery aneurysm associated with fistula and self-expandable metallic stent (SEMS), and [3] a typical Wernicke–Korsakoff syndrome linked to vitamin deficiency in patients who are, in fact, subjected to long-term fasting.

If the surgeon becomes concerned about a leak and a drain was left in place at the time of surgery, the drain fluid can be sent for an amylase level. If the fluid amylase level is much higher than normal serum levels (in the 1,000s), this suggests that saliva is entering the drain. Regardless of the drain amylase level, early imaging is warranted if clinical suspicion of a leak exists. An upper gastrointestinal contrast study is frequently used postoperatively to assess the presence of a gastric leak as well as demonstrate patency of the sleeve gastrectomy. In general, a water-soluble contrast material is used (Gastrografin). While standing, the patient swallows 20 mL of Gastrografin and radiographs are taken. The characteristics of a tubularized stomach (i.e., dimensions, emptying, and the presence or absence of leak or stricture) are then evaluated (Figs. 7 and 8). In case of doubt, or in order to increase sensitivity, abdominal computerized tomography (CT) scan can be performed. CT scan can provide additional information in regard to fluid collections or abscess in the left upper quadrant (Figs. 9 and 10) or the presence of subdiaphragmatic air (Fig. 11).

Abdominal CT scan should be performed with intravenous and oral contrast material. It is useful to identify the postoperative normal anatomy and the presence of complications after sleeve gastrectomy. Findings suggestive of GL are extravasation of contrast agent through the wall of the gastric sleeve, accumulation adjacent to the sleeve, free intra-abdominal liquid, free intra-abdominal gas, and residual contrast agent in the drainage tube.

Interventional options include surgery (laparoscopy or laparotomy with abdominal washout, abdominal drainage close to the staple line, and feeding jejunostomy), endoscopic procedures (self-expandable metallic stents (SEMS), clips, biological glue, pigtail drains, and T-tube gastrostomy drain), and radiological procedures (percutaneous drainage).

The management of the leak depends on the patient’s clinical condition. The surgeon managing this complication must have a clear treatment strategy or algorithm based on the patient’s status, the duration of the leak, and the resources available.

If the leak presents as a well-defined abscess several days or weeks after surgery and the patient is clinically stable, percutaneous image-guided drainage (Fig. 13) or pigtail drainage (Fig. 14), antibiotics, and nutritional support with parenteral nutrition or a nasojejunal tube is appropriate. If drainage is adequate, endoluminal therapies can be used to facilitate closure of the leak. This process often includes placement of endoscopic clips, fibrin glue (Fig. 15), or bioabsorbable fistula plugs and endoluminal stenting across the leak. Stenting has been shown to be effective in small series of selected cases, but results can be variable depending on the size and duration of the leak. Although placement of self-expanding, covered, or partially covered stents (Polyflex or WallFlex stents, Boston Scientific, Natick, MA) may be beneficial, the current stent technology is not ideal for this anatomy. The difficulty is in the two different lumen diameters and the curvature of the gastric lumen (Fig. 16). Before attempts at stenting, the extraluminal collection must be adequately addressed in all cases, and surgical placement of drains with washout of the infected field is often warranted to promote closure of the leak. Because successful outcomes after stenting often occur in carefully selected patients, evidence is currently insufficient to make any broad claims that stenting accelerates or promotes closure of leaks for all patients. Nevertheless, stenting may be a useful therapeutic adjunct in some patients and is associated with acceptable risk.

One advantage of stent placement in these patients is that it may allow patients to resume oral intake while the leak heals.

Patients who are manifesting signs of sepsis or are unstable should be managed operatively with laparoscopy or laparotomy (Fig. 17). Drainage and washout of the infected collection and wide drainage of the area is the primary goal of the operation. Primary closure of the defect can be performed if discovered early. Direct primary closure of the defect with or without sealants should be reserved for cases that were diagnosed early (within 24–48 h) and have good tissue viability. Closed suction or sump drains should be placed and the omentum can be sewn over the defect to help contain the contamination. If the patient is stable during the case, a feeding jejunostomy should be placed for long-term enteral access.

In contrast to a Roux-en-Y gastric bypass (RYGB), LSG leaks are more difficult to manage and tend to be more chronic in nature. Proximal leaks (Fig. 18) may be differentiated from distal ones due to the quality of material that may be seen in the drain. Proximal leaks often have saliva and gastric acid, while distal leaks may additionally drain bile. In proximal leaks the use of drains (surgical or percutaneous) plus alimentary support should be initiated. Complementary to the adequate drainage, the use of endoscopic procedures like fibrin sealant in combination with somatostatin and placement of endoluminal stents have promising results. There are less reports on the management of distal leaks; however, the same principles as previously described should be applied (Fig. 19). Rosenthal et al. [22] presented a case report with a distal and proximal disruption of the staple line. A T-tube gastrostomy with a large proximal and distal limb was placed into the most distal area of disruption. After thorough oversewing and drainage of the proximal site and T tube (distal), a feeding jejunostomy was placed. Four weeks postoperatively, the T tube was removed after the patient had a negative Gastrografin study and tolerated oral fluids with a clamped T tube. Persistent leaks (both proximal and distal) may require conversion to a low pressure system such as RYGB.