Per-oral oesophageal myotomy (POEM) is a natural orifice endoscopic surgery that has been gaining increasing use as an alternative to traditional oesophageal myotomies (e.g. Heller myotomy and Nissen fundoplication) to treat achalasia by weakening the lower oesophageal sphincter.
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Technique
The endoscopist insufflates the oesophagus with CO2 then creates a 2 cm opening approximately 12 cm above the squamocolumnar junction. A submucosal path is created through the opening to the lower oesophageal sphincter and usually into the cardia of the stomach. The sphincter/ circular muscle is then incised (myotomy). The endoscope is withdrawn and the mucosal opening is closed with staples. The whole procedure is performed beneath the mucosa under general anaesthesia.
Radiographic features
Most patients receive a fluoroscopic oesophageal swallow study either immediately after the procedure or soon after the procedure.
The most common scope approach is anteriorly in the oesophagus, so the RPO position is often best to profile the clips 2.
Water-soluble contrast (e.g. Gastrografin) is usually used first in case there is an occult perforation.
Normal findings
clips at the surface of the oesophagus, indicating the entrance to the submucosal tunnel (clips usually fall off with time)
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small amounts of pneumoperitoneum, pneumomediastinum, intramural gastric pneumatosis, retroperitoneal gas, as well as intramural dissection and contrast leak are common findings post procedure
due to leakage from CO2 instillation through the scope during the procedure
these usually resolve spontaneously and no further intervention is required
Treatment and prognosis
Complications
contrast leak outside the oesophagus (perforation)
a large amount of pneumoperitoneum (concerning for perforation)
distal sphincter dilatation less than 5 mm post POEM is considered poor response