Chapter 15: Peroral Endoscopic Myotomy (Poem)

INDICATIONS

Patients found to have achalasia are candidates for peroral endoscopic myotomy (POEM). Workup should include endoscopy, upper GI series, and high-resolution esophageal manometry to confirm the diagnosis of achalasia and rule out paraesophageal hernia or other pathology that might confound the creation of a submucosal tunnel. Although the presence of a hiatal hernia is not a strict contraindication to POEM, the patient should be counseled about the likelihood of reflux that will occur, because an antireflux procedure is not associated with this approach as with a traditional laparoscopic Heller myotomy. Patients should also be consented for laparoscopic surgery so that the threshold to convert to a laparoscopic or hybrid approach is low in the event of safety concerns.

PATIENT POSITIONING

The procedure should be performed in a traditional operating room capable of conversion to laparoscopic or open procedures if the need should arise. The bed is turned from the anesthesia console to allow maximal access to the head and neck region.

ANESTHESIA

General anesthesia should be performed to allow for maximal relaxation and safe manipulation of complex endoscopic equipment. An esophageal overtube should be placed to allow frequent exchanges of the scope when necessary.

OPERATIVE PROCEDURE

A transparent endoscopic cap attachment is placed on the end of a standard endoscope to allow greater viewing perspective and prevent smudging of the optical surface. A needle knife and triangular-tip knife are used for creation of the submucosal tunnel and myotomy (Figure 1A, B). Endoscopic insufflation should be performed with CO₂ rather than air as a pneumomediastinum is not unusual. A formal endoscopy is performed to identify the gastroesophageal (GE) junction and decompress the stomach. A dilute mixture of methylene blue and epinephrine is injected to tattoo the lesser curvature 2 to 3 cm distal to the GE junction.

The procedure begins by raising a submucosal wheal approximately 10 cm above the GE junction with a sclerotherapy needle and a dilute mixture of epinephrine and methylene blue. A needle knife is used to start the initial mucosal incision of the esophagus (Figure 2). A biliary dilation balloon is inserted into the incision and inflated to facilitate creation of a submucosal tunnel (Figures 3 and 4).

OPERATIVE PROCEDURE

The scope is advanced into the tunnel with the assistance of the needle knife to open the mucosotomy ...