Magnetic control for the vocal cord adduction in the canine.

An entirely satisfactory and physiologic solution to adduct paralyzed vocal cord during phonation, coughing, and swallowing has not yet been achieved. The authors noticed that velopharyngeal closure takes place simultaneously with adduction of vocal cords in order to perform phonation, coughing, and swallowing. We devised a new laryngeal pacing system to adduct the paralyzed vocal cord, utilizing velopharyngeal closure under magnetic control. Two mongrel dogs were anesthetized and the interior of the larynx was exposed using a Lynch suspension laryngoscope. A small magnet wrapped by thin Silastic was inserted into the nasal side of the soft palate via a small incision. After making a vertical midline neck incision, the pharynx was dissected and the Gaussmeter probe was inserted into the retropharyngeal space. The Gaussmeter probe was connected to the Gaussmeter and finally to the pacemaker. Electrodes were inserted into the paralyzed adductor laryngeal intrinsic muscles via punctures of the cricothyroid membrane. When the pacing system operated, arbitrarily elevated soft palate to the posterior pharyngeal wall brought about an abrupt increase in magnetic force and thus obvious adduction of the paralyzed vocal cords could be seen.