Benign esophageal leakages or fistula are frequently encountered and require urgent intervention to the high risk of sepsis and the high mortality rate. Anastomotic leakage may occur in up to 10 % of patients undergoing esophageal resection. Also iatrogenic perforation or Boerhaave syndrome have been successfully treated with SEMS. As shown in Fig. 5.2, the placement of covered or partially covered SEMS constitutes an indication to treat an esophageal fistula resulting in a valid alternative to surgery, favoring the healing of the defect in the esophageal wall, the control of sepsis, and a more rapid intake of an oral diet. A recent meta-analysis of Dasari et al. reported data on 117 patients from 12 studies [16]. Technical and clinical successes were 96.5 % and 86.2 %, respectively. Stent migration occurred in 11 % of treated patients. However, five patients had a perforation induced by stent, two of them due to erosion of the wall of the aorta [16]. Endoscopic reintervention and surgical intervention were needed in 5 % and 15 % of cases, respectively [16]. In the same meta-analysis, the authors also considered patients treated with SEPS: the data show that they have a higher incidence of migration and need more frequent endoscopic reoperation, while the need for a surgical intervention does not seem to significantly differ from that of SEMS [16]. The use of SEMS in the treatment of a defect in the esophageal wall must be always taken into account: the choice of the stent must take account of the greater risk of migration in the absence of stenosis. We believe the choice should fall on large-diameter partially covered SEMS. The removal must be programmed within 4–6 weeks, in order to minimize the risk of ingrowth. Also in this scenario, the stent-in-stent technique should be considered in case of embedment [13]. It is also necessary to remember that any periesophageal collection must be drained, and the patient must always be treated with broad-spectrum antibiotics.

Active bleeding from esophageal varices is considered a major cause of mortality in patients with decompensated liver cirrhosis. Treatment is currently based on vasoactive drugs, band ligation or sclerosis, and antibiotic therapy; however, they can fail in 10–15 % of patients. Tamponade balloon or the positioning of TIPSS may be proposed in these cases, however in clinical practice, TIPSS is not readily available quickly. Over the past 10 years, many cases of patients with refractory variceal bleeding treated with SEMS with excellent results have been described in literature, so that the 2015 Baveno Workshop on portal hypertension has proposed the placement of SEMS as a possible therapeutic option, awaiting further confirmations from clinical trials [17]. A review by Changela et al. showed data about 103 cases of patients treated with fully covered SEMS: Technical success rate was 97 %, with a bleeding control achieved in 96 % of treated patients. All SEMS were successfully removed after 4–14 days. Stent migration occurred in about 21 % of patients [18]. A more recent systematic review with meta-analysis took into account data on 13 studies [19]. The pooled estimate rates were 0.12 (95 % CI = 0.07–0.21) for variceal bleeding mortality and 0.18 (95 % CI = 0.11–0.29) for failure to control bleeding with SEMS [19]. The available data suggest that a proportion of less than 40 % of patients with refractory variceal bleeding dies 1 month after placement of SEMS. Therefore SEMS could be considered as a bridge therapy in selected patients undergoing other interventions such as TIPSS or liver transplantation. The choice must fall on a completely covered and large-diameter stent. The removal must be scheduled within 2 weeks, making it easier to prevent the removal of the device, reducing the risk of injury and variceal rebleeding.

Therapeutic interventions for endoscopic esophageal achalasia include pneumatic dilation, intrasphincteric injection of botulinum toxin, and most recently the peroral endoscopic myotomy (POEM). The rate of clinical remission obtained with pneumatic dilatation, however, dramatically decreases over time from 20 to 60 % in 10 years. Temporary placement of large-diameter SEMS at the level of the cardia has been proposed as a possible therapeutic intervention in patients with achalasia. The rationale of their use is linked to the possibility to perform a gradual and prolonged dilation at the level of the lower esophageal sphincter, which, compared to traditional pneumatic dilation, should secure better long-term results.

In a study by Ying-Sheng, 90 patients with achalasia have been treated with different size SEMS: 20, 25, and 30 mm. Partially covered SEMS have been deployed across the esophageal cardia, and they were left in place for 4–5 days, before being removed. Technical success was achieved in all patients; however, best results were obtained with larger-diameter SEMS: the treatment failure rate was lower in patients treated with 30 mm SEMS (13 %) compared to the other groups [20]. SEMS migration occurred more frequently in patients receiving 20 and 25 mm SEMS. Moreover, patients were followed up to 10 years and larger-diameter SEMS showed better long-term results [20]. Similar results have been reported also in other studies [21–23]. In another study comparing SEMS and pneumatic dilation, a temporary, 30-mm diameter SEMS was associated with a better long-term clinical efficacy in the treatment of patients with achalasia [22]. Similar better long-term outcomes have been shown in another study comparing removable SEMS and botulinum toxin injection [23]. While these data are promising, studies from Western countries are lacking, and SEMS dedicated to achalasia are not widespread used.

The use of SEMS deserves a special mention in the treatment of staple line dehiscence after laparoscopic sleeve gastrectomy. This is the most feared complication of this surgery, providing greater morbidity. Its incidence varies depending on the series but seems to have decreased over time from 2.5 % to 1.1 % [24]. However other authors reported higher incidence of leakages up to 20 %, also in experienced hands [25]. Leakage typically develops at the esophagogastric junction and proximal stomach, near the angle of His. The cause of leakage is to be attributed to an altered healing process of the suture line, which depends on many risk factors, such as ischemia due to the devascularization of gastric wall. An increased intraluminal pressure of gastric tube has also been invoked as another mechanism involved in staple line leaks, especially if the gastric tube is little distensible or if there is a stricture of the sleeve [26]. Although it is not accepted by all, in recent years, several authors have proposed the use of fully covered SEMS in the treatment of this type of fistula with variable results [27, 28]. Only the leakages located at the esophagogastric junction or the proximal portion of gastric tube are susceptible to such treatment. SEMS migration is the most frequent complication, occurring in up to 30 % of cases. Therefore these SEMS should be as wide and as long as possible, in order to prevent dislocation. Many authors remove them after 6–8 weeks to ensure complete healing of the fistula. Recently covered SEMS with a large diameter and length have been introduced on the market, dedicated to the treatment of staple line leaks postlaparoscopic sleeve gastrectomy (Megastent, Taewoong Medical co, South Korea). It is a completely coated prosthesis with a large diameter (24–28 mm) and varying in length from 15 to 23 cm. This stent has two large flares in the proximal and distal part, ensuring an optimal gripping. Moreover, given its length, the proximal and distal ends can be opened upstream of the leak in the esophagus and in the duodenal bulb, respectively. This allows to reset the high pressure within the gastric tube, promoting the healing of the fistula. A recent case series by Galloro et al. showed that Megastent was effective in four patients with staple leaks, allowing rapid resumption of enteral nutrition and early discharge [26] (Fig. 5.3).

Placement of SEMS within the low GI tract is an advanced endoscopic technique used to treat a variety of condition including obstruction, fistula, and perforation.

The most common indication for low GI tract stenting is the colon malignant obstruction. There are two major indications for colonic stenting in patients with colorectal cancer: palliation of advanced disease and preoperative decompression. In the latter case, placement of a stent can convert a surgical procedure from an emergent two-step procedure (including a colostomy) into an elective one-step resection with a primary anastomosis, which can be performed laparoscopically [29].

Large-bowel obstruction caused by advanced colon cancer occurs in three-fourths of all malignant colonic obstruction. The management of this severe clinical condition remains controversial.

The majority of colon cancer causing obstruction are localized to the left side of the colon, with the sigmoid colon being the most common location. Extrinsic colon cancer (in particular pelvic tumors) can infiltrate the colonic wall and may cause a lumen obstruction or a colonic compression. Malignant colonic obstruction may be treated by using conventional surgery with resection or diversion procedures, but patients presenting with malignant obstruction often are poor surgical candidates. Patients treated with a diverting colostomy frequently retain the stoma indefinitely because of the discovery of metastatic disease [30]. Urgent surgical intervention in this setting is associated with a mortality rate of 10 % and morbidity up to 40 % [31]. The most important endoscopic alternative to the urgent surgical management of malignant colonic obstruction is the placement of SEMS.

Over the last decade, many articles have been published on the subject of colonic stenting for malignant colonic obstruction, including randomized controlled trials (RCTs) and systematic reviews. However, the definitive role of self-expandable metal stents (SEMS) in the treatment of malignant colonic obstruction has not yet been clarified, and a collaborative approach to patient management, including surgeons and endoscopists, is recommended to guide patient care [31].