Vocal cord medialisation by transcutaneous injection of calcium hydroxyapatite

Abstract

Objectives: Various techniques of vocal cord medialization have been described. The 2 most commonly used procedures are medialization thyroplasty and injection augmentation of the vocal cord. Translaryngeal injection of agents to cause cord medialization has increasingly become the route of choice as it is quick, simple and does not require general anaesthesia. Various agents have been injected but none are without problems. Calcium hydroxyapatite has recently been advocated as a potentially superior alternative. The aims of this study were to investigate the short and medium term patient benefits of calcium hydroxyapatite for vocal cord medialization via trancutaneous injection. Methods: A retrospective analysis of 24 patients undergoing transcutaneous vocal cord injection with calcium hydroxyapatite was performed. The primary diagnosis was vocal cord paralysis in 20 patients and vocal cord scarring in the remaining 4. Results: The mean age of the patient group was 66.7 years (SD 15.7). Due to various factors including patient death and distance to travel, follow-up is incomplete. Maximum phonation time (MPT) was taken as the performance measure. Twenty-two patients had a preinjection MPT (average 4, SD 1.7); 12 patients had follow-up at 3 months (mean MPT 10.3, SD 6.5). The mean preinjection MPT of this group was 4.25 (SD 1.8); 5 patients had follow-up at 6 months (mean MPT 10.6, SD 3.0). The mean preinjection MPT of this group was 4.5 (SD 1.7). In 2 patients the injection of calcium hydroxyapatite entered the submucosal space of the vocal cord but only 1 patient required surgical removal of the substance. Conclusion: Transcutaneous injection of calcium hydroxyapatite gives satisfactory improvement in maximum phonation time for glottic insufficiency due to vocal cord paralysis in the short and medium term. Longer term follow-up studies are in progress and these will further evaluate the outcome and safety of calcium hydroxyapatite as a substance for vocal cord medialization.