High Incidence of Bellʼs Palsy After Mastoidectomy: A Longitudinal Follow-up Study

OBJECTIVE:The objective of this study was to compare the prevalence of Bellʼs palsy in participants who underwent mastoidectomy (to treat chronic otitis media) and nonmastoidectomy participants (control). METHODS:Using the national cohort study from the Korean Health Insurance Review and Assessment Service, mastoidectomy patients (2,045) and control participants (8,180) were matched 1:4 for age, sex, income, and region of residence. The prevalence of Bellʼs palsy in both the groups was measured from 0 to 10 years postoperation. RESULTS:In a sample of 1,025,340 Korean individuals, 7,070 were diagnosed or treated with Bellʼs palsy between 2002 and 2013; the annual incidence of Bellʼs palsy was 0.057%. The overall prevalence of Bellʼs palsy was three times higher in the mastoidectomy group (1.27%) than control group (0.49%) (p