Third Space Endoscopy: Lessons Learnt From a Decade of Submucosal Endoscopy.

Area of Science:

• Gastroenterology and Endoscopy
• Minimally Invasive Surgery

Background:

• Third space endoscopy (TSE), also known as submucosal endoscopy, enables access to deeper gastrointestinal layers.
• The development of per-oral endoscopic myotomy (POEM) a decade ago has spurred rapid growth in TSE procedures.
• TSE techniques create a submucosal tunnel for interventions, avoiding full-thickness perforation.

Purpose of the Study:

• To review the expanding field of third space endoscopy (TSE).
• To outline the techniques, indications, and current data for various TSE procedures.
• To highlight the safety profile and training requirements for TSE.

Main Methods:

• Review of existing literature on third space endoscopy (TSE) procedures.
• Description of the general technique common to all TSE interventions.
• Summary of data availability for specific procedures like POEM and submucosal tunneling endoscopic resection.

Main Results:

• TSE allows access to submucosal and deeper GI layers without full-thickness perforation.
• Numerous TSE procedures have been developed, including POEM, gastric-POEM, and Zenker POEM.
• Current data for TSE are mainly retrospective, with limited randomized trials and long-term follow-up.
• TSE procedures demonstrate an excellent safety profile, with most adverse events related to insufflation.

Conclusions:

• Third space endoscopy is a rapidly evolving field with diverse applications in gastrointestinal treatment.
• While generally safe, TSE requires specialized training and has a learning curve.
• Further randomized trials and long-term data are needed to fully establish the efficacy of various TSE procedures.