What is the POEM (Peroral Endoscopic Myotomy) procedure and when is it recommended for adults with achalasia who have not responded to other treatments?

POEM (Peroral Endoscopic Myotomy) for Achalasia

What is POEM?

POEM is a minimally invasive endoscopic procedure that creates a submucosal tunnel in the esophagus and performs a myotomy (cutting) of the circular muscle layer of the lower esophageal sphincter and distal esophagus to treat achalasia. 1

The technique involves:

• Creating a submucosal tunnel (mean length 12.4 cm) through an endoscopic mucosal entry point 2
• Performing endoscopic myotomy of circular muscle bundles (mean 8.1 cm total: 6.1 cm in distal esophagus and 2.0 cm in cardia) 2
• The myotomy length can be calibrated to the spastic segment visualized on high-resolution manometry or thickened segment on endoscopic ultrasound, typically 12-16 cm for Type III achalasia 3
• Confirming smooth endoscope passage through the gastroesophageal junction at procedure completion 2

When POEM is Recommended

Primary Indications by Achalasia Subtype

POEM should be considered as the preferred primary treatment for Type III (spastic) achalasia when expertise is available, as it allows for a longer myotomy necessary to treat the spastic contractions of the distal esophagus, with a 92% response rate in meta-analyses. 1, 3, 4

For Type I and Type II achalasia:

• POEM is a treatment option comparable to laparoscopic Heller myotomy (LHM) with fundoplication 1, 4
• POEM is superior to pneumatic dilation (PD), with emerging randomized controlled trial data showing greater effectiveness, though with higher post-treatment reflux risk 1, 4, 5

Failed Prior Treatment

POEM may be superior to pneumatic dilation for patients with failed initial POEM or laparoscopic Heller myotomy, with one randomized trial showing POEM achieved 62% success rate versus 27% for PD after failed LHM. 1

Critical Prerequisites

POEM should only be performed when ALL of the following criteria are met:

• The procedure must be performed by experienced physicians in high-volume centers, as 20-40 procedures are required to achieve competence 1, 3, 6
• Patients must have confirmed achalasia on high-resolution manometry with elevated integrated relaxation pressure 1
• No mechanical gastric outlet obstruction on esophagogastroduodenoscopy 1
• Delayed gastric emptying confirmed on solid-phase gastric emptying scan when gastroparesis is suspected 1

Post-POEM Management Requirements

Mandatory Reflux Management

All patients undergoing POEM must be counseled preoperatively that they will likely require indefinite proton pump inhibitor (PPI) therapy for symptomatic reflux or erosive esophagitis. 1

The evidence for post-POEM reflux is substantial:

• Abnormal acid exposure occurs in 41-56% of patients 1
• Erosive esophagitis develops in 41-65% of patients 1
• One-quarter of these patients are asymptomatic 1
• At 1-year follow-up, 59% had esophagitis on endoscopy, though only 31% had pathologic acid exposure on 24-hour pH monitoring 7

Pharmacologic acid suppression should be strongly considered immediately post-POEM, given the increased risk of postprocedure reflux and esophagitis. 1

Surveillance Requirements

Follow-up endoscopy and/or pH monitoring should be strongly considered in all patients 6-12 months after POEM for objective evaluation of abnormal acid exposure. 1

This is critical because:

• Patients with achalasia have a 5-fold higher risk for esophageal cancer compared to the general population (hazard ratio 4.6; 95% CI, 2.3-9.2) 1
• Reflux symptoms after POEM may not necessarily be due to acid reflux but could represent nonreflux esophageal acidification from food stasis or acid fermentation 1

Long-Term Outcomes

At 5-year follow-up:

• 83% of achalasia patients maintained symptomatic success (Eckardt score ≤3) 8
• No patients required retreatment for symptoms 8
• There was a small but significant worsening of symptoms between 2 and 5 years 8
• 38% had abnormal distal esophageal acid exposure on 24-hour pH monitoring 8
• 13% developed erosive esophagitis on endoscopy 8

Critical Pitfalls and Contraindications

End-Stage and Sigmoid Achalasia

Esophagectomy should be considered the primary treatment option for sigmoid achalasia with severe dilation and deformation, as it addresses irreversible structural changes and eliminates aspiration risk and malignancy risk. 6

If POEM is attempted in sigmoid esophagus:

• Expectations must be significantly reduced 6
• One report documents a doubling of adverse events compared to non-sigmoid cases 1, 6
• Most published POEM trials specifically excluded end-stage cases 1, 6

Patient Selection Errors to Avoid

Do not offer POEM to:

• Patients with opioid dependence until weaned off opioids and gastric emptying re-evaluated 1
• Most patients with post-infectious gastroparesis 1
• Patients at centers without adequate procedural volume and expertise 1, 3