Radiological study of the Laryngeal Mask

Lateral soft-tissue radiography was used to determine the location of the Laryngeal Mask (LM) in relation to the larynx and surrounding structures in 24 elderly male patients undergoing general anaesthesia. In a majority of cases (16 of 24) the epiglottis was within the cuff of the mask but without causing discernable airway obstruction in any case. One case of backfolding of the cuff occurred, and there was one case of gross misplacement (also clinically undetected). Supplementary information was obtained in 13 patients by the use of fibre-optic endoscopy, via the lumen of the LM, confirming the inclusion of the epiglottis within the mask and demonstrating a characteristic distortion by the LM of the normal laryngeal anatomy. It is concluded that inclusion of the epiglottis within the LM is commonplace, and misplacements may occur without clinical evidence of a compromised airway.