The aim of the study is to compare the effect of the C-MAC videolaryngoscope intubation technique vs. the conventional direct laryngoscope intubation technique on the cervical spine motion during intubation in patients with the simulated cervical immobilization.

When the intubation is required in patients with an injured cervical spine, securing the airway while minimizing C-spine motion to prevent neurological damage can be very difficult. The awake intubation using a flexible bronchoscope is preferred as it minimizes C-spine motion. However, in the emergent clinical practice, direct laryngoscopy with manual in-line stabilization is most commonly used, because it is quicker and does not require patient collaboration. Numerous alternatives to direct laryngoscopy and fiberoptic bronchoscopy have been studied. But, none of these methods combines the convenience of direct laryngoscopy and the C-spine immobility afforded by intubation using a fiberoptic bronchoscope patient with an injured C-spine.

The videolaryngoscopy has recently developed extensively and become more widely available. It has the potential of combining the advantages of both direct laryngoscopy and intubation using a fiberoptic bronchoscope. Indeed, it provides an indirect view of the glottis, which could diminish C-spine movement, but its handling shares many similarities with direct laryngoscopy, which could make it more convenient than the flexible bronchoscope.

In the previous study examining C-spine movement during direct laryngoscopy and GlideScope® videolaryngoscopy, found no difference in movement at the rostral level but showed significantly less movement of the inferior C-spine with GlideScope® videolaryngoscopy. We postulate that C-MAC videolaryngoscope will induce less movement than direct laryngoscopy. The effect of C-MAC videolaryngoscope intubation technique on cervical spine motion is not investigated yet.

In this study, C-spine stabilization will be provided by Philadelphia neck collar. We will investigate a prospective cinefluoroscopic study comparing C-spine motion during direct laryngoscopy and C-MAC videolaryngoscope in patients with an intact C-spine stabilized by Philadelphia collar.

The duration and maximum change for C-MAC videolaryngoscope intubation technique was compared to those with direct laryngoscopy at each motion segment using a Student's paired t-test.

Inclusion Criteria:

• Patients with American Society of Anesthesiologists physical status of 1-2 and age of 20-80 years undergoing elective endovascular coiling to secure cerebral aneurysm under general anesthesia in neuroangiographic rooms.

Exclusion Criteria:

• Patients with C-spine injury, C-spine disease
• Patients with past medical history of C-spine surgery or intervention
• Patients with the upper airway abnormalities, such as inflammation, abscesses, tumours, polyps, or trauma.
• Patients with past medical history of gastro-oesophageal reflux disease and previous airway surgery, a high risk of aspiration, coagulation disorders, or Hunt Hess grade of 3-5.
• Body mass index > 30