Regenerative medicine for complex gastrointestinal transmural defects: a silver bullet or just another tool in the endoscopist’s arsenal?

Gastrointestinal (GI) wall defects, also known as transmural defects, comprise three distinct entities: perforation, leak, and fistula [1]. While perforation may occur spontaneously (e.g. Boerhaave syndrome), be induced by foreign bodies, or result from endoscopic manipulation, leaks and fistulas are typically related to surgery or radiotherapy. A GI leak, for example, is characterized by the disruption of a surgical anastomosis, allowing contents to escape into the surrounding space. A fistula, in contrast, implies the presence of a tract connecting the GI lumen with the skin or a contiguous organ (e.g. a rectovaginal fistula). In chronic fistulas, the tract is typically lined with epithelium.