ASGE Annual GI Advanced Practice Provider Course (Virtual) (Day One) | March 2026-Third-space Endoscopy: POEM, G-POEM, and Z-POEM Innovative Approaches and Case Insights

Pdf Summary

Third-space endoscopy includes POEM, G-POEM, and Z-POEM—minimally invasive endoscopic “tunneling” procedures that cut targeted sphincter or muscle fibers to treat motility disorders. Peroral endoscopic myotomy (POEM) was developed for achalasia; gastric POEM (G-POEM) adapts the technique to perform pyloromyotomy for refractory gastroparesis; and Zenker’s POEM (Z-POEM) treats Zenker’s diverticulum by dividing the cricopharyngeal muscle. Advanced practice providers are central to recognizing symptoms, ordering and interpreting diagnostic tests, and providing peri-procedural counseling and follow-up.<br /><br />Achalasia is defined by impaired LES relaxation and absent/abnormal peristalsis (Types I–III per Chicago Classification), typically presenting with dysphagia to solids and liquids, chest pain, regurgitation, and weight loss. High-resolution manometry is the diagnostic gold standard; endoscopy and esophagram (classically “bird beak”) support diagnosis. Treatment options include medications, botulinum toxin or pneumatic dilation, laparoscopic Heller myotomy (LHM), and POEM. POEM is particularly useful for Type III achalasia and in patients with prior Heller or bariatric surgery, but may be less suitable for those unable to undergo anesthesia, with uncorrectable coagulopathy, or who wish to avoid long-term PPIs. Post-POEM care commonly includes overnight observation, next-day esophagram, staged diet advancement, short-course antibiotics, PPIs (often ≥3 months), and outcome tracking with Eckardt score; GERD risk is higher than with LHM.<br /><br />Gastroparesis involves delayed gastric emptying without obstruction, causing nausea/vomiting, postprandial fullness, early satiety, bloating, and pain. Diagnosis relies on EGD and gastric emptying scan, with symptom severity measured by GCSI. For medically refractory cases, G-POEM is a safe, effective option with success comparable to surgical pyloroplasty and typically shorter hospitalization; adverse events are usually mild.<br /><br />Zenker’s diverticulum is an older-age, male-predominant pharyngoesophageal outpouching due to cricopharyngeal dysfunction, presenting with dysphagia, halitosis, cough, weight loss, and aspiration risk. Diagnosed by barium studies, Z-POEM achieves ~85–93% clinical success with a favorable safety profile. Pre- and post-procedure expectation setting is emphasized across all three procedures.

Asset Subtitle

Katelyn Cookson, PA-C

Keywords

third-space endoscopy

peroral endoscopic myotomy (POEM)

gastric POEM (G-POEM)

Zenker’s POEM (Z-POEM)

achalasia (Chicago Classification Types I–III)

high-resolution manometry

gastroparesis

gastric emptying scintigraphy

Zenker’s diverticulum

post-POEM gastroesophageal reflux disease (GERD)