Analysis of pressure applied during microlaryngoscopy.

Direct laryngoscopy is the most predominantly used technique in laryngology, with the fulcrum-based laryngoscope serving as the most popular instrument. The purpose of this study was to accurately calculate and measure the pressure acting on the laryngopharynx and the tongue base during microlaryngoscopy. The relationship between postoperative throat pain and the time and pressure applied during microlaryngoscopy were also investigated. Fifty patients undergoing microlaryngeal surgery were included in this prospective study. Parameters that may help predict difficult laryngeal exposure were measured in the patients before microlaryngoscopy. Using static equilibrium and the law of the lever, the pressure acting on the laryngopharynx and the tongue base were calculated and related parameters were then tested for their influence on pressure. The time and pressure applied during microlaryngoscopy of each patient were compared with postoperative throat pain grade. The mean pressure was 292 ± 109 mmHg and was significantly influenced by BMI, neck circumference and full mouth opening, whereas no gender-based differences of any kind were found. The pressure applied during microlaryngoscopy was extremely high in patients with difficult laryngeal exposure (376 ± 62 mmHg), serving as a possible reason for the presence of throat pain or complications present following surgery. However, it was found that the duration of suspension laryngoscopy, not the pressure, had the most significant correlation with postoperative throat pain.