CERVICAL-SPINE MOVEMENT DURING LARYNGOSCOPY WITH THE BULLARD, MACINTOSH, AND MILLER LARYNGOSCOPES

Background: Direct laryngoscopy requires movement of the head, neck, a nd cervical spine, Spine movement may be Limited for anatomic reasons or because of cervical spine injury, The Bullard laryngoscope, a rigid fiberoptic laryngoscope, may cause less neck flexion and head extensi on than conventional laryngoscopes. The purpose of this study was to c ompare head extension (measured externally), cervical spine extension (measured radiographically), and laryngeal view obtained with the Bull ard, Macintosh, and Miller laryngoscopes. Methods: Anesthesia was indu ced in 35 ASA 1-3 elective surgery patients. Patients lay on a rigid b oard with head in neutral position. Laryngoscopy was performed three t imes, changing between the Bullard, Macintosh, and Miller laryngoscope s. Head extension was measured with an angle finder attached to goggle s worn by the patient, The best laryngeal view with each laryngoscope was assessed by the laryngoscopist. In eight patients, lateral cervica l spine radiographs were taken before and during laryngoscopy with the Bullard and Macintosh blades. Results: Median values for external hea d extension were 11 degrees, 10 degrees, and 2 degrees with the Macint osh, Miller, and Bullard laryngoscopy (P < 0.01), respectively, Signif icant reductions in radiographic cervical spine extension were found f or the Bullard compared to the Macintosh blade at the atlantooccipital joint, atlantoaxial joint, and C3-C4. Median atlantooccipital extensi on angles were 6 degrees and 12 degrees for the Bullard and Macintosh laryngoscopes, respectively. The larynx could be exposed in all patien ts with the Bullard but only in 90% with conventional laryngoscope (P < 0.01). Conclusions: The Bullard laryngoscope caused less head extens ion and cervical spine extension than conventional laryngoscopes and r esulted in a better view, It may be useful in care of patients in whom cervical spine movement is limited or undesirable.