Management of Facial Nerve Canal Dehiscence

Diagnostic Evaluation

High-resolution temporal bone CT is the preferred imaging modality to evaluate the facial nerve canal and identify dehiscence, as recommended by the American College of Radiology, with high sensitivity and specificity 1, 2
MRI provides complementary information, particularly for evaluating the nerve itself and surrounding soft tissues, as recommended by the American College of Radiology 1, 2
Electrodiagnostic testing (ENoG and EMG) is crucial for determining the severity of nerve dysfunction and guiding treatment decisions, with a strength of evidence level of high, according to the American Academy of Otolaryngology-Head and Neck Surgery 3, 4

For symptomatic FCD with facial nerve dysfunction, the American Academy of Otolaryngology-Head and Neck Surgery recommends initial assessment using House-Brackmann facial nerve grading and electrodiagnostic testing (ENoG and EMG), with a strength of evidence level of high 3, 5
Surgical intervention is recommended for complete facial paralysis with >90% reduction in amplitude on ENoG testing and absent volitional nerve activity on EMG, with a strength of evidence level of high, according to the American Academy of Otolaryngology-Head and Neck Surgery 3, 4
Middle fossa decompression is the preferred surgical approach for labyrinthine segment dehiscence, with a success rate of 91% in achieving House-Brackmann I/II outcomes, as reported by the American Academy of Otolaryngology-Head and Neck Surgery 3, 5

The American Academy of Otolaryngology-Head and Neck Surgery recommends that middle fossa approach requires craniotomy but allows for removal of bone surrounding the facial nerve at the meatal foramen without affecting hearing structures, with a strength of evidence level of high 3, 5
Timing is critical, with best outcomes seen when surgery is performed within 14 days of symptom onset, as recommended by the American Academy of Otolaryngology-Head and Neck Surgery, with a strength of evidence level of high 3, 4

For elderly patients (>80 years), the American Academy of Otolaryngology-Head and Neck Surgery recommends conservative surveillance or stereotactic radiosurgery may be preferred over microsurgical resection, with a strength of evidence level of moderate 6
In cases where FCD is associated with tumors like vestibular schwannomas, management should follow specific guidelines for those conditions, as recommended by the American Academy of Otolaryngology-Head and Neck Surgery, with a strength of evidence level of high 6