Upper cervical vertebrae movement during intubating laryngeal mask, fibreoptic and direct laryngoscopy: a video-fluoroscopic study.

BACKGROUND AND OBJECTIVE

Minimizing cervical vertebrae motion during endotracheal intubation is important in patients with cervical instability. The aim of this study was to compare upper cervical spine extension during endotracheal intubation using three different techniques.

METHODS

Duration of intubation and movement of upper cervical vertebrae during endotracheal intubation were compared in 33 patients undergoing lumbar laminectomy. Patients requiring tracheal intubation under general anaesthesia and neuromuscular blockade were randomly allocated into three groups - direct laryngoscopy, intubating laryngeal mask (LM) airway and fibreoptic laryngoscopy. The procedure was recorded by video-fluoroscopy and analysed with computer-assisted measurements. The maximum movement of the C1/C2 and C2/C3 vertebrae during intubation were obtained. Data were analysed using one-way analysis of variance with Bonferroni and Kruskal-Wallis tests.

RESULTS

We found statistically significant movement between the first and second, but not between the second and third cervical vertebrae. The mean (+/-SD) movement at C1/C2 was 10.2 +/- 7.3 degrees with direct laryngoscopy, 5.0 +/- 6.3 degrees with LM and 1.6 +/- 3.2 degrees with fibreoptic laryngoscopy. This difference was statistically significant (P = 0.01) between the direct and fibreoptic laryngoscopy groups. The maximum movement at C2/C3 was 2.2 +/- 10.1 degrees with direct laryngoscopy, 3.5 +/- 5.1 degrees with LM and 0.5 +/- 3.2 degrees with fibreoptic laryngoscopy. Duration of intubation was significantly longer in the intubating LM group (P < 0.001).

CONCLUSION

We conclude that fibreoptic laryngoscopy is the more suitable intubation technique when cervical spine movement is not desired.