The most common cause of facial paralysis is Bell's palsy. The incidence of Bell's palsy is around 20-30 per 100,000 people per year, or about 1 in 60 people in a lifetime ( De Almeida JR et al. Management of Bell's palsy: clinical practice guideline. CMAJ. 2014 Sep 2; 186(12): 917–922).
Bell's palsy is not synonymous with facial paralysis. It should not be viewed as just a diagnosis of exclusion, but has distinct clinical characteristics.
Bell's palsy involves all branches of the facial nerve and the paralysis occurs over hours to 1-2 days. Once established, reinnervation usually occurs with near full recovery over the subsequent 6 months.
Therefore, if a facial paralysis is slowly progressive, and/or involves only some branches of the facial nerve, and/or shows no recovery over time (6 months), then another diagnosis must be considered.
2. Bell's palsy treatment
Most Bell's palsy patients are managed non-surgically.
Patients seek surgical opinion when there is no recovery, asymmetry, or with problematic synkinesis.
Management is often directed by patient concerns regarding both aesthetics and the degree of disability. Treatment is individualized and includes all the available options for facial paralysis reconstruction.