From the Guidelines
Facial nerve decompression in Bell's palsy should be performed via a middle fossa approach, as it allows for removal of the bone surrounding the facial nerve at the meatal foramen and fallopian canal without affecting the structures of hearing. This approach is supported by the study by Gantz et al 1, which provides compelling evidence in support of middle fossa decompression of the facial nerve in Bell’s palsy, with 91% of patients achieving a House-Brackmann facial nerve outcome of I/II compared to 42% in the steroid-only control group. The middle fossa approach requires a craniotomy, but it is a more targeted approach that avoids the risks associated with transmastoid decompression, such as conductive hearing loss 1.
Key points to consider when deciding on surgical decompression include:
- The severity of the condition, with electrodiagnostic testing showing greater than 90% degeneration within 14 days of onset 1
- The lack of improvement after 3-6 months of conservative management
- The potential risks associated with the procedure, including hearing loss, balance problems, CSF leak, and infection 1
- The fact that most Bell's palsy cases (about 85%) recover spontaneously with medical management, making surgical decompression necessary only in select cases with poor prognostic indicators 1
It is essential to weigh the potential benefits of surgical decompression against the risks and to consider the individual patient's circumstances and prognosis when making a decision 1.
From the Research
Facial Nerve Decompression in Bell's Palsy
- The middle cranial fossa approach is recommended for facial nerve decompression in Bell's palsy, as it provides access to the primary site of lesion while preserving hearing 2, 3.
- This approach is particularly beneficial for patients with complete facial paralysis secondary to Bell's palsy or temporal bone trauma, more than 90% degeneration on electroneurography testing, and absent voluntary electromyography within 14 days of onset 2, 3.
- Facial nerve decompression via the middle fossa approach has been shown to result in good facial nerve outcomes, with 71.4% of patients regaining normal or near-normal facial function within 1 year after surgery 3.
- The subpetrous approach is another option for facial nerve decompression, and has been used in some cases with favorable results 4.
- The timing of decompression is crucial, with most studies recommending surgery within 14 days of symptom onset 2, 3.
Key Considerations
- Patients should be carefully selected for facial nerve decompression, based on clinical and electrodiagnostic testing 2, 5, 3.
- The benefits and risks of decompression should be discussed with patients, including the potential for improved facial function and the risks of complications 2, 3.
- Further research is needed to fully establish the effectiveness of facial nerve decompression for Bell's palsy, particularly in comparison to other treatment options such as steroids and antiviral agents 6, 5.