Evolution of endoluminal treatment of Zenker's diverticulum and complete pharyngo-oesophageal obstruction

Purpose of review Endoscopic approaches to surgery of the foregut, in particular, the upper oesophageal sphincter (UES), continue to develop, providing options for management that were previously unavailable. This review examines endoluminal surgical tunnelling approaches (third space endoscopy) to treat Zenker diverticulum and the more rare condition of complete oesophageal stenosis. Recent findings Endoluminal surgical approaches to the UES such as Z-POEM (per-oral endoscopic myotomy) that utilize gastroscopes and upper gastrointestinal endoscopic instrumentation, are increasingly being utilized for management of UES dysfunction, with excellent safety and utility. Advantages of these techniques include overcoming access issues (trismus, osteophytes, and neck rigidity), ability to address the septum to its base whilst preserving mucosa, and enhanced visualization provided by insufflation in the surgical field. Multiple variations of these techniques are being reported, and the scope of application is expanding. POETRE (per-oral endoscopic tunnelling for restoration of the oesophagus) has been described to manage complete oesophageal luminal occlusion, and we describe application of this technique as a variation of the ‘rendezvous procedure’ to successfully reestablish communication from hypopharynx to oesophagus and stomach. Summary Minimal access endoluminal ‘third space’ approaches to the upper oesophageal sphincter and oesophagus provide safe access, enhanced visualization and the ability to manage UES and oesophageal disease in the elderly population where anatomical issues may impede rigid endoscopy and open approaches contribute enhanced risk of complications. Z-POEM and POETRE can be successfully applied to treat Zenker diverticuli, cricopharyngeal dysfunction and complete hypopharyngeal–oesophageal obstruction. Third space endoscopy promotes increased collaboration between clinicians and subspecialities for the benefit of patients.