• Defects of GI tract encompass numerous conditions involving damage to the wall of hollow organs of gastrointestinal system. These range from chemical burns of esophagus to a variety of perforating conditions, such as fistulas and anastomotic leaks, affecting esophagus and intestine and resulting from a variety of factors including both natural causes and surgical interventions.
• A somewhat separate class of injuries is caused by high velocity kinetic objects, when several zones are formed in the wall of GI organs affected, including the necrotic zone and the molecular shock zone. The final picture of organ damage is formed only 24–72 hours after the injury making it difficult to evaluate the extent of the damage and the scale of surgical intervention required to treat it.
• The main challenge of managing all these conditions comes from the fact that aggressive acidic and rich with digestive enzyme environment of GI tract continuously irritates the site of injury and hampers the healing process. Further, in case of perforating injuries, the non-sterile contents of GI tract can migrate outside the lumen of a damaged organ and seed infection in the neighboring cavities of the body.
• For all the above reasons, natural or even assisted enteral feeding of patients is often impossible condemning them to weeks or even months of receiving critical nutrition via a parenteral route. Not only this weakens patients, the lack of stimulation of the natural function of GI tract results in paresis and damage of mucosa, which in turn lead to migration and mixing of microbiome and increases permeability of intestinal wall. This results in bacterial and enterotoxin translocation further increasing the risk of systemic inflammatory reactions and infectious complications.

CURRENT TREATMENT APPROACHES

• Treatment of defects of GI tract often involves surgical procedures aiming to either excise the site of injury or close the defect. More conservative approaches involve the use of stents (SEMS) covering the defect. Another commonly used approach, especially for chronic cases such as fistulas and anastomotic leaks, involves endoluminal vacuum therapy (EVT) when a device such as Eso-Sponge® or Endo-SPONGE® is placed endoscopically near or sometimes inside the site of injury and controlled negative pressure is applied to achieve active drainage and sanation of the injured site and promote its healing. The use of a foam (e.g. polyurethane) sponge with such devices is believed to improve the granulation of the wound and enhance the curative effect. More recently new device, VacStent GI^TM, has been introduced aiming to combine the benefits of EVT and covered stents.
• The disadvantage of all approaches involving EVT is that the negative pressure is applied in a relatively open environment and thus may not be as effective. Further, the site of injury remains accessible to the surrounding biofluids, which may further damage of infect it. EVT cannot be combined with delivery of medicines to the injured site. Feeding of patients would interfere with the action of standard EVT devices (but not VacStent GI^TM) and thus is impossible while they are used. Migration of devices, pulmonary aspiration related complications and necessity for multiple endoscopic procedures are among other disadvantages of the above methods.