Background: Anterograde transnasal flexible endoscopy of the pharynx, larynx, and proximal trachea without sedation has been established since the 1990s. Retroflexed endoscopic functional analysis has recently been introduced.
Objectives: Adding retroflexed functional endoscopy from the oral cavity up to the duodenum to anterograde diagnostics allows the precise demonstration of how different factors interact in a complex way, e. g., in case of dysphagia or pathological reflux.
Materials and methods: A 70-cm-long high-definition endoscope without a channel system is equipped with a 200° retroflexed view, a mm-cm scale, and a roller system. The endoscope can be lengthened, stopped, or shortened during the procedure. Standard positions, viewing directions and display details ensure that findings are comparable. Mastication, food transport and digestion are observed in the unsedated patient.
Results: Depending on indication and symptoms, we defined a diagnostic algorithm including three specific pathways: (1) for conditions that originate in the oral cavity, larynx or pharynx, (2) for suspected reflux disease, or for neurological or neuromuscular disorders of food transport, (3) for duodenogastric, gastroesophageal and esophagopharyngeal reflux, as well for benign or malignant tumors.
Conclusion: The advantages of functional endoscopy have an impact not only on the medical staff and patients. Its precise and participatory approach is relevant to healthcare, enlarges the diagnostic horizon, and forms a basis for interdisciplinary collaboration.
Keywords: Diagnostic techniques and procedures; Dysphagia; Patient participation; Reflux; Transnasal endoscopy without sedation.