[Cervical spine movement during orotracheal intubation using the McCoy laryngoscope compared with the Macintosh and the Miller laryngoscopes].

The movement of cervical spine during orotracheal intubation was compared using the McCoy, Macintosh or Miller laryngoscope blade. Twenty ASA 1-2 patients requiring tracheal intubation were studied. Following induction of anesthesia and obtaining muscle relaxation, the cross-table lateral X-ray was taken before and during laryngoscopy using three types of laryngoscopes. Degree of cervical spine movement was evaluated by measuring the distance between the spinous processes of C1 and the occiput, and the amount of displacement of C1 and C5 against C3 by tracing on each films. The results indicated that delta C1-occiput was larger and delta C1 + C5 smaller with the McCoy laryngoscope compared with the others. The use of the McCoy laryngoscope results in less cervical spine movement during laryngoscopy and therefore should be of particular benefit in the presence of cervical spine instability as well as in the normal patients.