A Study to Evaluate Safety and Effectiveness of G-POEM for Gastroparesis

Inclusion Criteria: * Symptoms of chronic nausea or vomiting compatible with gastroparesis (idiopathic or diabetic) must be present for at least one year (does not have to be contiguous) prior to registration. * Must have a mean total Gastroparesis Cardinal Symptom Index (GCSI) score of ≥ 3 at screening visit. * Refractory gastroparesis, defined using our previously published data5, as a failure to improve over the last 6 months, despite an adequate trial of one or more standard prokinetics (metoclopramide, erythromycin, prucalopride), antinauseants (5-HT3 antagonists, promethazine, prochlorperazine, dronabinol), or neuromodulators (mirtazapine, buspirone). * Moderate to severe delay in gastric emptying, defined as \> 25% solid retained at 4 hours or \> 75% retained at 2 hours. The qualifying gastric emptying scintigraphy must be performed within 18 months prior to registration or can be the baseline gastric emptying. * No evidence of mechanical obstruction based on upper GI endoscopy or upper GI series in their medical history. Exclusion Criteria: * Another active disorder which could explain symptoms in the opinion of the investigator. * Gastric retention of solids at 4 hours \< 25% or \< 75% at 2 hours. * Ongoing use of prokinetic agents (e.g., metoclopramide, erythromycin, prucalopride) GLP -1 analog or agonists, or drugs that slow down gastric emptying (narcotics). Neuromodulators such as tricyclic antidepressants (amitriptyline or nortriptyline) or others that are being used at stable doses for a month prior to randomization may continue at the discretion of the care provider. * Significant systemic illness such as chronic renal failure (adjusted for age) or liver disease as defined by Child-Pugh score of 10 or greater. * Poorly controlled diabetes with HbA1c of greater than 10% at time of screening. * New medications for gastroparesis-related symptoms started within 1 month prior to registration. * Pregnancy or nursing. * Failure to give informed consent. * Any other condition, which in the opinion of the investigator would impede compliance or hinder completion of the study. * Botox injection into the pylorus within 3 months prior to registration. * Allergy to eggs or Egg Beaters and Ensure.