Randomized cinefluoroscopic comparison of cervical spine motion using McGrath series 5 and Macintosh laryngoscope for intubation with manual in-line stabilization

Abstract

Background: Intubation in patients with suspected cervical spine injury must be cautiously performed to avoid any further neurologic trauma. Several intubation techniques have been introduced to minimize cervical spine motion such as the use of the videolaryngoscope.

Objective: The present study aims to compare the movement of the cervical spine during intubation by using McGrath series 5 videolaryngoscope (MGL) and that of the conventional Macintosh laryngoscope from cinefluoroscopic imaging.

Material and method: Twenty-two patients undergoing elective orthopedic surgery that did not involve cervical spine procedure and required general anesthesia were recruited into the study. All patients were randomized either to have intubation with MGL (n = 11) or Macintosh laryngoscope (n = 11) in a neutral position with manual in-line stabilization (MILS). The primary outcome was the cervical vertebral angle changes pre- and post-intubation, measured by cinefluoroscopy. The number of intubation attempts, the laryngoscopic view, the time to intubation, and the incidence ofany complications were recorded as well.

Results: Eleven patients were included in each group without any exclusion from the study. The cervical vertebral angle changes pre- and post-intubation with the MGL was less than with the Macintosh laryngoscope at C3/4 (2.00 vs. 4.27 degrees, respectively; p-value = 0.034) and the cumulative changes of all cervical spine levels (9.18 vs. 17.18 degrees, respectively; p-value = 0.017). However, the time to intubation with the MGL was longer (35.07 vs. 23.21 seconds, p-value = 0.004), the laryngoscope view was better. There were no statistically significant differences in the intubation success rate, the number of attempts, and the incidence of complications.

Conclusion: Orotracheal intubation with MGL provided less cervical spine motion and improved visualization of the vocal cords, without causing adverse consequences as compared with Macintosh laryngoscope and MILS.