double balloon enteroscopy

endoscopy esophagus endoscopic double balloon gastric stomach muscle system duodenum procedure treatment achalasia minimally vector gastroscopy invasive disorder mucosa submucosa gastrointestinal intestine insertion bowel inflated biopsy tool endoscope esophageal les tunnel nonsurgical sphincter fibers stricture anatomical junction digestive gastroenterologist illustration enteroscopy colon poster therapy gastroesophageal tube wall medical biology