Effects of medialization laryngoplasty on airway resistance: a pilot study.

Abstract

To investigate the effects of medialization laryngoplasty on laryngeal airway resistance at various clinically relevant flow rates. This study was conducted using a total of 13 laboratory experiments. Two of the experiments were used to validate the cadaveric model employed. Eleven experiments were used to quantify airway resistance relative to increasing medialization laryngoplasty stent size. With autopsy consent the authors obtained 13 consecutive and anatomically complete larynges for experimentation. A thyrotomy window measuring 8 x 6 mm was made on the left side of the thyroid cartilage. A #4 laryngeal mask was secured to the pharyngeal airway with sutures. Eleven experiments were conducted at the same flow rates using increasingly larger stents from 1 mm to 11 mm in size. Using the Bernoulli equation, the pressure measured at the proximal end of the laryngeal mask is representative of the pressure drop across the airway. The experimental model was validated in two experiments using flow rates between 5 and 50 L/min and stents measured at 5, 10, 15, and 20 mm. Average results from the 11 experiments indicate that at increasing levels of medialization, from 0 to 11 mm, there is essentially the same pressure drop across the larynx at a given flow rate. At physiologic airflow rates in a cadaveric model, medialization laryngoplasty implants of 11 mm or less seem to have no obvious effect on airway resistance.