Weight loss (kg)
Past Medical History
A detailed past medical history is important in the preoperative workup of a POEM patient. Knowledge of prior endoscopic treatments of achalasia such as Botulinum toxin injection or pneumatic dilation is important in determining the relative hostility of the submucosal plane during dissection. A prior esophageal perforation at the time of pneumatic dilation may effectively obliterate the submucosal plane. Prior exposure to mediastinal radiation also results in fibrosis of the esophageal layers. Cardiovascular or pulmonary comorbidities must also be considered during preoperative planning.
All patients, in whom POEM is being considered should undergo the following diagnostic tests to confirm the diagnosis, aid in patient selection as well as operative planning.
An upper endoscopy is usually the first test that was performed in the evaluation of a patient with dysphagia. Upper endoscopy might reveal a tortuous, dilated, sigmoid esophagus with retained saliva, fluid, or even food. Esophagitis might be seen due to stasis, especially of pills. Stasis might lead to esophageal candidiasis, commonly presenting with signs of esophagitis and overlying white exudate. Biopsies should always be performed to confirm Candida esophagitis in order to facilitate preoperative antifungal treatment.
Although rare, a preoperative upper endoscopy is essential to rule out a diagnosis of pseudoachalasia in which an infiltrating gastroesophageal junction tumor causes esophageal outflow obstruction mimicking achalasia. A high index of suspicion for pseudoachalasia should be maintained for patients older than 60 with a rapid progression of symptoms and excessive weight loss. Another rare but serious condition which can be detected endoscopically is the presence of esophageal varices. Computerized tomography or endoscopic ultrasound are helpful adjuncts to help confirm the diagnosis of pseudoachalasia and/or varices when suspected. The presence of either pseudoachalasia or esophageal varices is a contraindication to POEM and likely the completion of esophageal myotomy regardless of approach.
Although an esophagram can be normal in patients with early stages of achalasia, classically it reveals a tight narrowing at the gastroesophageal junction with a bird beak appearance, impaired LES relaxation, esophageal dilation, esophageal tertiary contractions, and poor esophageal emptying. A Timed Barium Swallow (TBS) provides information not only on esophageal anatomy but also on emptying. The TBS includes spot images that are performed at 1 min, 2 min, and 5 min after a barium bolus of 200 cm3. The contrast column height and width reported in centimeters indicate the relative severity of the esophagogastric outlet obstruction. This test is also useful to evaluate postoperative improvements in esophageal emptying.