Intracordal fat assessment by 3-dimensional imaging after autologous fat injection in patients with thyroidectomy-induced unilateral vocal cord paralysis

Background: Complications of thyroidectomy are the most frequent cause of unilateral vocal cord paralysis (UVCP) in Taiwan. Autologous fat injection for UVCP is a well-established procedure for temporary symptom relief. The aims of this study were to identify the long-term residual fat volume by 3-dimensional computed tomography (3-D CT) and to investigate the voice outcome. Methods: During this cross-sectional study, 28 consecutive patients who had undergone lipoinjection surgery for symptomatic UVCP resulting from thyroidectomy were enrolled. They received 3-D CT evaluations of the larynx and upper airway after lipoinjection surgery to assess the residual fat volume. Results: The mean duration from lipoinjection surgery to 3-D CT study was 26 months (range, 12-58). The mean residual fat volume remained consistent (0.39 ± 0.35 mL; range, 0.01-1.6). The maximal phonation time, s/z ratio, jitter, and harmonic-to-noise ratio were significantly improved during follow-up. Conclusion: Injected fat can survive chronically and provide clinically important improvement in voice in the patients with throidectomy-induced UVCP.