Peroral Endoscopic Myotomy (POEM) for Achalasia

1. Introduction

• Patient undergoes general anesthesia with endotracheal intubation
• Ensure that the endotracheal tube (ETT) is positioned to the side of the patient’s mouth to allow for each placement of the endoscope
• Patient should remain in supine position
• Once the esophagus is intubated, an overtube is advanced over the endoscope to protect the oropharynx from scope trauma, prevent ETT dislodgment, and facilitate multiple removal and insertion of the endoscope if needed

2. Creation of Mucosal Incision

1. Irrigate Gastric and Esophageal Lumen
• Irrigate with bacitracin solution
• Irrigation allows you to clearly visualize the lumen of the esophagus and the stomach, decrease bacterial load
2. Identify Squamocolumnar Junction
• Measure the distance from the squamocolumnar junction to the incisors to plan the location of your mucosotomy and the length of your myotomy
• Remove the scope and attach the clear distal cap to its end prior to performing the mucosotomy
3. Check Orientation of Scope
• Injection of blue dye into the field (but not into tissues) can help ensure that the endoscope is appropriately positioned to perform an anterior mucosal incision
• Correct orientation of the endoscope if necessary
• After measurement of the correct distance to pass the endoscopic needle, placement of tape on the endoscopic needle wire allows you to easily find the correct distance to pass the needle
4. Create Submucosal Cushion
• Creating a submucosal cushion allows you to more safely incise the mucosa and reduce the risk of a full-thickness perforation
• We aim to create a cushion and subsequent mucosotomy at the 2 o’clock position along the anterior aspect of the esophagus
• Suction the selected aspect of the mucosa into the clear distal cap of the endoscope
• Carefully insert the needle into the mucosa
• Slowly inject blue dye into the submucosa, visualizing the mucosa lifting into a cushion
5. Create 1.5-cm Vertical Mucosal Incision
• Keep the submucosal cushion suctioned into the clear distal cap of the endoscope
• Exchange the needle for an endoscopic knife
• Using the “Cut” option on the ERBE generator, create a 1.5-cm vertical mucosal incision along the submucosal cushion
• The assistant can help position the endoscope to allow the surgeon’s endoscopic knife to progress along the intended incision site
• Take care to avoid past-pointing the knife and perforating the full-thickness of the esophagus
• Visualize circular muscle fibers to ensure complete incision of the mucosa
• Once the appropriate mucosal incision has been made, direct the clear distal cap of the endoscope into the incision and point the endoscope downward to prepare for submucosal tunneling toward the stomach

3. Submucosal Tunneling

1. Use Indigo Carmine/Epinephrine Solution to Lift Mucosa off Circular Muscle Fibers
2. Advance Distally Taking Care Not to Injure Mucosa
• Once indigo carmine/epinephrine solution has been used to help elevate the mucosa off of the circular muscle fibers, slowly advance the scope distally
• Use the endoscopic knife to gently separate any areolar connective tissue between the mucosa and the circular muscle fibers
• You can alternate between injection of solution to lift the mucosa and use of the knife to separate areolar tissue as you progress distally
• The palisading vessels of the esophagus act as a landmark to identify the gastroesophageal junction
• If progression of tunneling fails, can begin your myotomy of the circular muscle fibers at that point to continue distal progress
3. Assess Location of Tunnel
• Once you complete the submucosal tunnel, exit the tunnel and insert the endoscope back through the lumen of the esophagus
• Assess the length of the submucosal tunnel relative to the squamocolumnar junction to ensure appropriate length of the tunnel
• Once confirmed, re-enter the submucosal tunnel

4. Myotomy

1. Start at Convenient Point and Proceed Distally
2. Selective Myotomy of Circular Muscle Fibers
• Use the endoscopic knife to carefully divide the circular muscle fibers, starting 5 cm above the lower esophageal sphincter and extending 3 cm beyond it
• Take care to avoid large vessels within the wall of the esophagus
• Avoid injury to the mucosa
3. Reassess Integrity of Mucosa
• Once myotomy has been completed above and below the squamocolumnar junction, pass the endoscope through the lumen of the esophagus to assess the integrity of the mucosa

5. Closure of Mucosal Incision

• Multiple clips are used to close the length of the mucosal incision

6. Post-op Remarks

• If a full-thickness injury occurs, ensure that the submucosal tunnel is closed adequately