Modified thyroplasty for unilateral vocal fold paralysis using an adjustable titanium implant.

This study aimed to describe a new titanium thyroplasty implant that can be adjusted with a screw. Six Beagle dogs were randomly divided into experimental and control groups (n = 3). The titanium screw was implanted in the experimental group after the left recurrent laryngeal nerve was cut off under general anaesthesia. This procedure caused arytenoid cartilage internal shift, allowing the vocal cord to locate at the median and the glottis to close during phonation. No other operation was conducted in the control group. Each group, respectively, underwent video laryngoscopy, CT scan and histopathology before and after operation. After 4 months of follow-up, the video laryngoscopy results showed that the left arytenoid cartilage in the experimental group underwent internal adduct and shift, whereas the left vocal cords in the control group located at the paramedian position and exhibited fissure during phonation. CT scan results showed that the adjustable titanium screw was in proper position. Postoperative pathological examination showed that, in addition to early local inflammation, the laryngeal muscle may atrophy. The adjustable titanium screw requires a simple operation and can be significantly adjusted. The effect of the operation can be immediately observed without rejection. Therefore, this method is an efficient treatment for unilateral vocal cord paralysis.