Facial nerve palsy secondary to cochlear implant

Case contributed by Ali Alsmair
Diagnosis almost certain

Presentation

The patient presented with left-sided facial palsy, which developed after a left cochlear implant.

Patient Data

Age: 25 years
Gender: Male

The cochlear implant inserted through a posterior tympanostomy through the round window.

The cochlear implant tip is located in quadrant VIII of the cochlea.

When the cochlear implant passes through the left mastoid, it seems to be causing compression on the mastoid portion of the facial nerve against adjacent bone with focal thinning of the facial nerve at this level.

Fluid filling the left mastoid air cells.

Polypoid mucosal thickening in bilateral maxillary and right ethmoid sinuses.

Right-sided nasal septal deviation.

The facial nerve (arrows) is crossed by the cochlear implant wire, which is causing marked compression and focal thinning of it, representing facial nerve injury.

Case Discussion

When reporting a cochlear implant CT study, it is important to describe the insertion of cochlear implant wire, (which is in most cases through the round window or adjacent to it) and the level of cochlear implant wire tip insertion. As the cochlea has levels from I-X where the tip of the cochlear implant wire inserts into.

In this study, the sagittal oblique images are the best to assess the level of the cochlea where the tip of the cochlear implant wire inserts into.

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