Infraorbital nerve dehiscence: the anatomic cause of maxillary sinus "vacuum headache"?

Vacuum disorders of the paranasal sinuses are well described. Patients with facial pain in the distribution of the infraorbital nerve are often labelled as suffering from a "vacuum maxillary sinusitis" and empirically treated by intranasal antrostomy. A variety of mechanisms have been postulated for the production of symptoms in this condition, but all ignore the fact that the maxillary sinus is a relatively insensitive structure. This article introduces a dehiscence of the bony infraorbital nerve canal within the antrum as an anatomic variant and suggests that it may provide the anatomic basis for vacuum sinusitis in the presence of a small natural ostium. Definitive diagnosis is made by outpatient antroscopy, and surgical treatment takes the form of a middle or inferior meatal antrostomy. Persistent symptoms may benefit from an infraorbital neuropexy to provide added protection to the exposed nerve.