Radiological Assessment Of Cervical Spine Mobility Comparing Direct Laryngoscopy With Miller Blade And Video-Laryngoscopy With CMAC In Healthy Adults

Study Objective: Quantify cervical spine range of motion during laryngoscopy via either direct laryngoscopy with a Miller blade or via video laryngoscopy with a CMAC system. Design: Prospective case series Setting: Interventional radiology suite at an academic medical center Patients: Five adults requiring general anesthesia with tracheal intubation to facilitate interventional radiology procedures Interventions: Fluoroscopic imaging of cervical spine anatomy prior to induction of general anesthesia and then during both direct laryngoscopy and video laryngoscopy Measurements: Quantification of angles between skull base and prespecified cervical vertebrae and between the first cervical vertebrae and lower prespecified cervical vertebrae. These groups of measurement either do or do not account for movement of the atlanto-occipital joint, respectively. Main Results: There was a tendency toward reduced cervical extension both relative to skull base and intrinsicly within the cervical spine during laryngoscopy with the CMAC video laryngoscope as compared to direct laryngoscopy with a Miller blade. Conclusions: We describe a novel technique to quantify cervical motion during laryngoscopy. Laryngoscopy with a CMAC video laryngoscope may reduce cervical extension as compared to direct laryngoscopy with a Miller blade. Video laryngoscopy may attenuate cervical extension during laryngoscopy, an effect that can be useful in patients with cervical spine disease or instability.