To analyze the characteristics of adult idiopathic unilateral vocal-fold paralysis.

Retrospective study of diagnostic problems, clinical data and recovery in an inception cohort of 100 adult patients with idiopathic unilateral vocal-fold paralysis (Group A) and comparison with a cohort of 211 patients with isolated non-idiopathic non-traumatic unilateral vocal-fold paralysis (Group B).

Diagnostic problems were noted in 24% of cases in Group A: eight patients with concomitant common upper aerodigestive tract infection, five patients with a concomitant condition liable to induce immunodepression and 11 patients in whom a malignant tumor occurred along the path of the ipsilateral vagus and inferior laryngeal nerves or in the ipsilateral paralyzed larynx. There was no recovery of vocal-fold motion beyond 51 months after onset of paralysis. The 5-year actuarial estimate for recovery differed significantly (P<0.0001): 53.2% in Group A versus 17.9% in Group B. In Group A, recovery occurred before the end of the second year following paralysis onset in 93% of cases. On univariate analysis, recovery in Group A was associated with younger age (P=0.0033), shorter time to consultation (P<0.0001), and absence of oncologic history (P<0.028). In case of non-recovery in Group A, malignant tumor along the ipsilateral vagus or inferior laryngeal nerve was found in 17.2% of cases, 81% of which manifesting during the 30 months following the onset of vocal-fold paralysis.

In non-traumatic vocal-fold paralysis in adult patients, without recovery of vocal-fold motion, a minimum three years’ regular follow-up is recommended.