A two-dimensional model of anatomic relationships during laryngoscopy

Area of Science:

• Anesthesiology
• Medical Education
• Anatomy

Background:

• Direct laryngoscopy view is limited to one operator, hindering teaching and understanding of difficult intubations.
• Anatomic factors influencing laryngoscopy are internal and difficult to visualize.
• A novel, adjustable, 2D sagittal plane head and neck model was developed.

Purpose of the Study:

• To validate a new mannequin for direct laryngoscopy simulation.
• To assess the impact of anatomical variations and equipment on the laryngoscopic view.
• To evaluate the model's potential for teaching and research.

Main Methods:

• Model parameters were compared to established literature values.
• Glottic exposure was systematically evaluated across varying jaw lengths and interincisor gaps.
• Different laryngoscope blades (Macintosh 3, Miller 2, Macintosh 4) were tested.

Main Results:

• The model accurately replicated key airway dimensions and joint mobilities of a 16-year-old male.
• Glottic exposure significantly decreased below a critical mouth opening threshold (2.4 cm).
• Limited mouth opening and short mandible length severely restricted visualization, with Macintosh 4 blade showing the closest approach to viewing the posterior cords.

Conclusions:

• The validated model effectively represents average 16-year-old male anatomy and mobility.
• The model can elucidate the influence of anatomical relationships on laryngoscopy.
• Further objective assessment is required to confirm its utility in education and research of intubation difficulty.