The investigation and management of petrous apex erosion

Disease of the apex of the petrous temporal bone, while rarely encountered, can present a unique challenge to the otologist. Lesions tend to be advanced at presentation, as massive bony erosion can remain asymptomatic. When symptoms occur, they reflect involvement of the neurovascular contents of the temporal bone. The earliest clinical features, such as headache, facial numbness and middle-ear effusion, do not immediately suggest the site or gravity of the underlying pathology. Anterior extension of disease may produce ophthalmoplegia and diplopia whilst posterior spread involves the lower cranial nerves, within the internal auditory canal, jugular foramen and hypoglossal canal. Evaluation of apical disease relies on radiological evidence of bony erosion and should include polytomography, CT scanning and angiography. The clinical features and radiological findings in a series of patients with various apical lesions are presented. The surgical approaches reviewed aim to reconcile the need for adequate access to this remote site, with the desire to preserve residual facial nerve and cochlear function and to protect the brain-stem.