Application of an Immobilization Device for the Modified Killian’s Method

Background The hypopharynx is a closed space that is difficult to observe. The modified Killian's (MK) method was introduced to obtain wider exposure. However, this method requires keeping the head forward during the examination. Postural maintenance might be problematic. To use the MK method safely for a thorough endoscopic examination, we introduced a new body immobilization device. The aim of this study was to evaluate the effectiveness of this body immobilization device. Methods Twenty-five patients underwent transnasal laryngoscopy using the MK method with the immobilization device. This device consists of a board to place the chest and a shaft. We classified hypopharynx visualization using a 5-point scale, in various combinations of head torsion, Valsalva maneuver, and MK position. Furthermore, we classified the feasibility of the MK method for 54 patients. Age, BMI, and performance status were evaluated by MK position feasibility class. Results The MK method with the body immobilization device was completed in all patients. It was significantly associated with higher hypopharyngeal visibility score. BMI and performance status were significantly associated with MK method feasibility. There were no significant differences in hypopharynx visualization scores with versus without this device for the patients that could maintain the MK position on their own. Conclusion For patients with poor nutrition or poor ability to perform activities of daily living, it was difficult to maintain the MK position. Thus, this immobilization device might be useful to complete the MK method and provide accurate detection of hypopharyngeal lesions in these patients.