Aerodynamic and acoustic parameters in CO2 laser posterior transverse cordotomy for bilateral vocal fold paralysis

The aim of this prospective study was to analyse airway improvement and aco ustic and aerodynamic parameters after CO2 laser posterior transverse cordo tomy (LPTC) in bilateral vocal fold paralysis (BVFP). Four patients (2 male s, 2 females) were recorded pre- and post-operatively at 1, 3, 6, 12 and 24 months. Forced inspiratory volume during the first second (FIV), vital cap acity, peakflow, and forced expiratory volume during the first second (FEV) were measured with the Gould II spirometer. Acoustic frequency features (a verage fundamental frequency, standard deviation, jitter, shimmer and harmo nic-to-noise ratio) and speech duration parameters (maximum phonation time, number of words read per minute, and number of words per breath) were meas ured. Aerodynamic parameters were measured with the Aerophone II. Three tas ks were completed. Pneumo-phonatory parameters in "maximum sustained phonat ion" and in "comfortable phonation", and laryngeal aerodynamic parameters ( intraoral air pressure, oral airflow and sound pressure level) were measure d non-invasively. Glottal resistance and vocal efficiency were calculated. FIV increased significantly after LPTC (p = 0.01). Postoperatively, frequen cy features were undetectable by standard commercialized algorithms. Acoust ic and aerodynamic parameters improved in the measures obtained at the 6th postoperative month. These results were stable 2 years postoperatively in a ll cases. We conclude that laryngeal aerodynamic parameters can be used obj ectively to follow patients longitudinally after LPTC.