Epidemiology of vocal fold paralyses after total thyroidectomy for well-differentiated thyroid cancer in a Medicare population

Abstract

Objectives: The population-level incidence of vocal fold paralysis after thyroidectomy for well-differentiated thyroid carcinoma (WDTC) is not known. This study aimed to measure longitudinal incidence of postoperative vocal fold paralyses and need for directed interventions in the Medicare population undergoing total thyroidectomy for WDTC.

Study design: Retrospective cohort study.

Setting: US population.

Subjects and methods: Subjects were Medicare beneficiaries. SEER-Medicare data (1991-2009) were used to identify beneficiaries who underwent total thyroidectomy for WDTC. Incident vocal fold paralyses and directed interventions were identified. Multivariate analyses were used to determine factors associated with odds of developing these surgical complications.

Results: Of 5670 total thyroidectomies for WDTC, 9.5% were complicated by vocal fold paralysis (8.2% unilateral vocal fold paralysis [UVFP]; 1.3% bilateral vocal fold paralysis [BVFP]). Rate of paralyses decreased 5% annually from 1991 to 2009 (odds ratio 0.95; 95% confidence interval, 0.93-0.97; P < .001). Overall, 22% of patients with vocal fold paralysis required surgical intervention (UVFP 21%, BVFP 28%). Multivariate logistic regression revealed that the odds of postthyroidectomy paralysis increased with each additional year of age, with non-Caucasian race, with particular histologic types, with advanced stage, and in particular registry regions.

Conclusion: Annual rates of postthyroidectomy vocal fold paralyses are decreasing among Medicare beneficiaries with WDTC. High incidence in this aged population is likely due to a preponderance of temporary paralyses, which is supported by the need for directed intervention in less than a quarter of affected patients. Further population-based studies are needed to refine the population incidence and risk factors for paralyses in the aging population.

Keywords: Medicare; bilateral vocal fold paralysis; epidemiology; incidence; thyroid cancer; thyroidectomy; unilateral vocal fold paralysis; vocal fold paralysis.

Figure 1

Study Flow diagram of Medicare beneficiaries who had uninterrupted enrollment in Part A and B and first diagnosis of WDTC that underwent total thyroidectomy between 1991 – 2009

Figure 2

Annual Incidence of Unilateral Vocal Fold Paralysis (Solid) and Bilateral Vocal Fold Paralysis (Dashed) among Medicare Beneficiaries Undergoing Total Thyroidectomy for WDTC (1991–2009)