Iatrogenic Vocal Fold Paralysis: A Population-Based Cohort Study in Taiwan

Objective: Iatrogenic vocal fold paralysis is an important issue in laryngology, yet there are few population-based studies regarding the epidemiology. This study used a nationwide population-based claims database (the National Health Insurance Research Database) to investigate the epidemiology of iatrogenic unilateral and bilateral vocal fold paralysis (UVFP/BVFP) among the general adult population in Taiwan. Method: This study analyzed patients (20-90 years old) who underwent thyroid, parathyroid, thoracic, cardiac, or anterior cervical spine operations with vocal fold paralysis among adults in Taiwan from January 1, 2007 to December 31, 2013. The codes for vocal fold paralysis were defined by International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM). Claims data in the Taiwan National Health Insurance Research Database were used. Results: The most commonly performed operations which were related to vocal fold paralysis in Taiwan were, in descending order of frequency, thyroid, cervical spine, cardiac, thoracic (esophagectomy), and parathyroid operations. The operations that put laryngeal nerves at risk (ONRs) most commonly associated with a diagnosis of UVFP were, in descending order of frequency, thoracic, thyroid, parathyroid, cardiac, and cervical spine. For both UVFP and BVFP, the most commonly associated age group was 51 to 60. For both UVFP and BVFP, the more commonly associated sex was women. Increased length of stay was associated with a higher incidence of UVFP and BVFP. Charlson medical co-morbidity index (CCI) was not associated with UVFP but BVFP was associated with higher Charlson medical co-morbidity scores. Conclusions: Thyroid operations, age 51 to 60, longer hospital stays are associated with vocal fold paralysis. Overall women are more surgically affected than men. This is the first population-based study of iatrogenic vocal fold paralysis.