The goal of this observational study is to learn about the best indications and techniques regarding endoscopic vacuum therapy (EVT) in patients with a transmural defect in the upper gastrointestinal (GI) tract (e.g. anastomotic leakage, Boerhaave syndrome, iatrogenic perforation, other). The main questions it aims to answer are:

• What is the success rate of EVT for transmural defects in the upper GI tract?
• What are the best indications for EVT in the upper GI tract? (e.g. etiology, patient characteristics, defect characteristics)
• What are the best techniques for EVT in the upper GI tract? (e.g. EsoSponge, VACStent, vacuum pressure, intraluminal/intracavitary) Participants will be asked for informed consent to retrospectively and prospectively collect data on EVT.

Transmural defects in the upper gastrointestinal (GI) tract are defined as a disruption or injury extending through all layers of the oesophageal or gastric wall. These defects can result from various causes, including anastomotic leakage (AL) after oesophago-gastric surgery, iatrogenic perforation, Boerhaave syndrome, or trauma. Transmural defects in the upper GI tract are associated with serious consequences, such as leakage of saliva, gastric contents, and bile into the mediastinum, triggering an inflammatory response. Untreated or inadequately managed mediastinitis can lead to serious morbidity, sepsis, and mortality. Therefore, timely diagnosis and treatment of these defects is crucial. There are several treatment options for transmural defects in the upper GI tract. Conservative management involves a nil by mouth protocol, antibiotics, and (percutaneous) drainage. Endoscopic treatments include self-expandable metallic stents (SEMS), through-the-scope clips, over-the-scope clips, suturing with overstitch, and most recently, endoscopic vacuum therapy (EVT). Historically, SEMS has been the most used treatment option for transmural defects in the upper GI tract. However, persisting leakage and complications such as dislocation of the stent are not uncommon. Besides that, not all defects are suitable for stenting and additional percutaneous drainage is often necessary, but not always possible. Surgical treatment, such as a re-anastomosis or resection of the gastric conduit with construction of a cervical esophagostomy is generally required in severely septic patients. The choice of treatment depends on factors such as the location and size of the leakage, severity of symptoms, and presence of conduit ischemia or necrosis. In the past decade, EVT has been established as an effective and safe endoscopic treatment option, and it was found to be superior in terms of success rate in AL healing compared to other treatments. However, the implementation of EVT in clinical practice might be hindered by multiple challenges and questions regarding indications and techniques. This study aims to answer remaining questions and bundle expertise, to be able to determine the best indications and techniques of EVT, to reach the full potential of the treatment.

Inclusion Criteria:

• Treated with EVT for anastomotic leakage after esophago-gastric surgery
• Signed informed consent form
• 18 years or older

Exclusion Criteria:

• No signed informed consent

Patients treated with EVT for a transmural defect in the upper GI tract, including anastomotic leakage, Boerhaave syndrome, iatrogenic perforations, trauma, etc.