This study evaluated the effects of the diameter of facial canal segments on the ipsilateral recurrence of idiopathic peripheral facial paralysis.

This study enrolled 20 patients with ipsilateral recurrent idiopathic peripheral facial paralysis. Measurements were made at the meatal foramen and mid-level of the labyrinthine segment and the narrowest and widest diameters of the mastoid and tympanic segments using the curved planar reformation technique with high-resolution computed tomography.

The diameters of the labyrinthine segment measured at the meatal foramen and mid-level segments and the narrowest and widest diameters of the tympanic and mastoid segments on the recurrent paralytic side were significantly smaller than the diameters of the segments on the healthy side.

The narrowness of the facial canal segments may be a risk factor in recurrent idiopathic peripheral facial paralysis.

To evaluate mastoid pneumatisation and facial canal dimensions.

In this retrospective study, 169 multidetector computed tomography scans of temporal bone were reviewed. Facial canal dimensions were evaluated at the labyrinthine, tympanic and mastoid segments using axial and coronal multidetector computed tomography scans of temporal bone. Mastoid pneumatisation and facial canal dehiscence were evaluated. Facial canal dehiscence was measured if it was found to be present.

This study showed that facial canal dimensions decreased in pneumatised mastoids. Facial canal dimensions in females were smaller than in males. Facial canal dehiscence was detected in 5.9 per cent and 6.5 per cent of the patients on the right and left sides, respectively. No correlations were found between facial canal dehiscence and mastoid pneumatisation. The length of dehiscence was 1.92 ± 0.44 mm (range, 0.86–2.51 mm) on the left side. In older subjects, left facial canal dehiscence was detected more, and the length of the dehiscence increased.

This study concluded that during surgery, facial canal dehiscence should be kept in mind in order to avoid complications.