Duodenal wall perforations require early closure because large amounts of intestinal contents leak into the peritoneum. Endoscopic techniques are determined based on the type and size of perforation and the endoscopist expertise available at the center [15,16]. The most important step before the closing procedure is thorough aspiration of the duodenal contents through the perforated hole.

A duodenal perforation of <10 mm in diameter can be closed easily with endoclips [17] by using a single-channel endoscope or lateral scope without changing the scope. Throughthe-scope (TTS) clips are widely used for closing luminal perforations [18], achieving technical success in 90% of gut perforations [6]. However, a large perforation (>20 mm) located at angulation is difficult to close by using TTS clips alone. When luminal closure with TTS clips fail, alternative methods using fibrin glue [19], endoclips and endoloops [20], purse-string suture [21], or band ligation [22] are applied [15,16]. Fibrin glue spray through a standard ERCP catheter between the clips could obliterate the perforation site and adhere multiple clips to each other [19]. Multiple endoclips and single or double endoloops are also effective for endoscopic closure of large duodenal perforations [20,21]. Another alternative method for duodenal closure is endoscopic band ligation (EBL) [22]. EBL could be easily performed for perforations 1 to 2 cm in diameter regardless of the site or angle when a perforation is detected during the procedure [23]. Gastroscopy attached with single- or multiple-band ligators in a transparent cap can approach the edge of the perforation. The perforated wall, along with peritoneal fat, is sucked into the ligator cup. One or two bands are subsequently released, resulting in closure of the perforation. Sucking together the duodenal wall and nearby omentum is helpful for complete closure of the perforation by making an omental patch endoscopically [24]. When a residual defect is suspected, additional endoclips can be applied at the edges of the perforation (Fig. 3) [25]. Duodenal wall perforation can be easily ligated because of a thin wall structure [26]. Endoscopic devices such as endoclip, endoloop, ligation band, and fibrin glue are usually available in an endoscopy unit and can be applied as soon as perforation occurs.

Specialized devices such as over-the-scope clipping device (OTSC) [27], endoscopic suturing (OverStitch; Apollo Endosurgery, Austin, TX, USA) [28], and open-pore film drainage [29] are reported as useful and effective for large luminal perforation.

OTSC revealed an 88% technical success rate [6]. OTSCs can close defects by up to 20 mm. Detailed OTSC techniques are as follows: OTSC in an endoscopic cap is placed over the mucosal defect. A twin grasper captures opposite sides of an open defect and apposes the tissue by using left- and right-sided graspers. The tissue in the graspers is pulled into the cap device, and then a clip is applied (Fig. 4). Compared with the TTS clip, the OTSC has higher compression force and enables capture of a larger tissue volume [30]. However, OTSC is not widely available and requires training before application in human patients [31].

Endoscopic suturing devices such as Eagle Claw (Olympus, Tokyo, Japan) and Purse String Suturing Device (LSI Solutions, Victor, NY, USA), which are attached to the end of a therapeutic double channel endoscope, allow full-thickness tissue apposition [32]. The device can be used multiple times without the need to remove the scope from the patient. However, endoscopic suturing devices are not widely available and are difficult to operate within the narrow duodenal lumen. They have been investigated in animals but have not been reported for clinical closure of duodenal perforations [33].

Another new technique is vacuum therapy with openpore film drainage, which is used for duodenal perforations that occur during ERCP [29]. The procedure consists of placing a drainage tube, which is wrapped with an open pore film, in the duodenal wall defect and application of vacuum for evacuation and collapse of the stomach and duodenum. Gastric, biliary, and pancreatic liquids are drained in an intraluminal direction continuously, and the transmural defect is closed simultaneously; thereby, preventing further extraluminal contamination (Fig. 5).

Most cases of periampullary or ductal perforation are managed with biliary diversion and endoscopic closure to prevent retroperitoneal fluid leakage [13]. Biliary diversion is achieved with biliary stent or nasobiliary drainage. A fully covered self-expandable metal stent (FCSEMS) can be placed to drain the bile duct and occlude the leak site in perivaterian perforations (Fig. 6) [34]. A recent study reported that the benefits of FCSEMS in the perivaterian perforation area are painless course, lower leukocyte counts, and short hospital stay compared with conservative treatment alone [35]. The efficacy of TTS clips in closing periampullary perforations is unknown. However, it is technically difficult and has a risk of clipping the ampulla [36,37].

Ductal perforations are usually small in size and improve with conservative management [3]. Perforation of the distal bile duct often can be managed by placement of plastic stents and, more recently, by FCSEMS [13]. If endoscopy fails to treat the perforation, percutaneous biliary drainage above the level of the perforation is an alternative treatment [2].

Retroperitoneal air alone (type IV) is developed by compressed air leakage [38,39]. It does not need treatment. Pneumoperitoneum can be present in up to 29% of asymptomatic patients who undergo uncomplicated procedures [40].