Third Space Endoscopic Therapies for Benign Motility Disorders: A Narrative Review.

Key Takeaways for GI Nurses

• Peroral endoscopic myotomy (POEM) is now first-line therapy for achalasia, endorsed by ASGE, ACG, and SAGES, with long-term clinical success exceeding 90% at 7 years — nurses should expect increasing procedural volume and patient inquiries about this option.
• Third-space endoscopy (TSE) is a rapidly expanding platform now applied beyond achalasia to spastic esophageal disorders, esophagogastric junction outflow obstruction, Zenker's and epiphrenic diverticula (Z-POEM/D-POEM), and refractory gastroparesis (gastric per-oral pyloromyotomy) — endoscopy teams need working familiarity with multiple submucosal tunneling procedures, not just POEM for achalasia.
• Intraoperative use of the endoluminal functional lumen imaging probe (FLIP) is increasingly incorporated to guide myotomy and reduce post-procedure gastroesophageal reflux — nurses assisting in these cases should understand FLIP setup, calibration, and data interpretation to support real-time decision-making.
• As myotomy technique (length, orientation, depth) continues to evolve, standardized nursing protocols for pre-procedure workup, intraprocedural monitoring, and post-procedure care must keep pace with these technical refinements.

Clinical Relevance

This review underscores that third-space endoscopy has moved from a novel technique to an established, guideline-endorsed therapy for achalasia, with a rapidly broadening scope of indications. For endoscopy nurses, this shift has direct implications for pre-procedure patient education. Patients referred for POEM often arrive with limited understanding of the submucosal tunneling approach, and nurses are frequently the point of contact for explaining the procedure, addressing anxiety, and reinforcing realistic expectations about symptom relief and potential adverse effects such as post-procedural GER — a known trade-off with myotomy that the abstract specifically highlights as a target for technique refinement.

From an operational standpoint, the expansion of TSE into diverticular disease (Z-POEM, D-POEM) and gastroparesis (gastric per-oral pyloromyotomy) means endoscopy units will need to accommodate a wider variety of specialized instrumentation, longer procedure times, and more complex sedation or anesthesia coordination. Nurses involved in scheduling, room turnover, and equipment management should anticipate the need for dedicated TSE trays and staff cross-training, since these procedures share core submucosal dissection principles but differ in anatomic approach and risk profile. Additionally, the incorporation of intraoperative FLIP technology introduces a new monitoring tool that circulating and procedural nurses should become comfortable operating and documenting, as it directly informs the endoscopist's technical decisions during the case.

Professionally, this evolving landscape presents an opportunity for endoscopy nurses to pursue targeted continuing education in advanced therapeutic endoscopy. As TSE procedures diversify and long-term outcome data accumulate, nurses who understand the nuances of each technique — including differences in myotomy planning, expected adverse events, and recovery trajectories — will be better positioned to provide informed post-procedure surveillance, recognize early complications, and contribute meaningfully to multidisciplinary discussions about patient selection and follow-up planning.

Bottom Line

POEM has firmly established itself as first-line therapy for achalasia with excellent long-term success, and the broader third-space endoscopy platform is rapidly expanding to treat spastic esophageal disorders, diverticula, and gastroparesis — GI nurses should prioritize building familiarity with these varied procedures, their instrumentation (including intraoperative FLIP use), and their distinct post-procedure care needs to support safe, high-quality patient outcomes as this technology continues to evolve.