Facial baroparesis: a review

Area of Science:

• Neurology
• Diving Medicine
• Aerospace Medicine

Background:

• Impaired eustachian tube function can lead to middle ear overpressure after ascent in diving or aviation.
• A defect in the facial canal wall predisposes individuals to seventh cranial nerve injury from this overpressure.
• This condition, known as facial baroparesis, can also be associated with alternobaric vertigo if middle ear pressure is asymmetric.

Purpose of the Study:

• To describe facial baroparesis, a form of facial palsy linked to barotrauma.
• To highlight the causative relationship between middle ear overpressure and facial nerve injury.
• To emphasize the importance of recognizing facial baroparesis to prevent misdiagnosis and inappropriate treatment.

Main Methods:

• Review of existing literature on facial baroparesis and related conditions.
• Analysis of reported cases linking middle ear overpressure to facial nerve palsy.
• Comparison with similar conditions like fifth cranial nerve palsy in divers.

Main Results:

• Facial baroparesis results from ischemic neurapraxia of the seventh cranial nerve due to middle ear overpressure.
• The condition's onset is rapid after pressure reduction and resolves with pressure changes or middle ear decompression.
• Animal experiments support the transient compression-induced ischemic neurapraxia mechanism.
• A similar condition affects the fifth cranial nerve due to maxillary sinus compression in divers.

Conclusions:

• Facial baroparesis is an under-reported but significant condition, with 23 cases in the literature.
• Misdiagnosis as Type II Decompression Sickness (DCS) or air embolism can lead to prolonged recompression and delayed return to diving.
• Awareness of facial baroparesis is essential for correct diagnosis and management, preventing unnecessary treatments and potential revocation of diving licenses.