Tactile sensation to the oropharynx and hypopharynx and larynx is supplied by the internal branch of the superior laryngeal nerve and by the pharyngeal branches of the ninth and tenth cranial nerves via the pharyngeal plexus. These may be blocked precisely by a technique of percutaneous superior laryngeal nerve and transpharyngeal pharyngeal plexus infiltration, allowing rapid, comfortable production of anesthesia for peroral endoscopy. Minimal patient cooperation is required. Results have been successful in more than 500 patients, and no complications have been attributed to the technique.
Jafek BW, Bauknight RS, Calcaterra TC. Percutaneous Anesthesia for Endoscopy. Arch Surg. 1972;104(5):658-661. doi:10.1001/archsurg.1972.04180050034008