Movement of the upper cervical spine during laryngoscopy: a comparison of the Bonfils intubation fibrescope and the Macintosh laryngoscope

The movements of the upper cervical spine were measured by fluoroscopy in 20 patients during laryngoscopy with the Bonfils intubation fibrescope and the Macintosh laryngoscope. Laryngoscopy with both the Bonfils intubation fibrescope and the Macintosh laryngoscope resulted in significant extension of the cervical spine as compared to the neutral position but this extension was significantly less with the Bonfils intubation fibrescope than with the Macintosh (p = 0.001). However, the atlanto-occipital distance was significantly greater during laryngoscopy with the Bonfils intubation fibrescope (p = 0.002), and the angle between the occiput and C1 differed significantly between the two techniques (p = 0.001). With the Bonfils intubation fibrescope, significantly less extension was also found at the C1/C2 and C3/C4 levels (p = 0.001 and p = 0.049, respectively). There is therefore significantly less movement of the upper cervical spine during laryngoscopy with the Bonfils fibrescope compared with the Macintosh laryngoscope.