Dizziness after head trauma: clinical and morphologic findings.

Twelve patients with balance problems resulting from head injury were treated by a translabyrinthine or middle fossa vestibular neurectomy. The clinical, otoneurologic, and surgical data combined with morphologic findings on the removed operative eighth nerve specimens were evaluated with the aim of deciding the site of primary lesion in each case. In six patients a peripheral lesion was interpreted. Four of them had features of delayed endolymphatic hydrops syndrome, the fifth patient might have suffered a fracture of the stapedial footplate with associated perilymphatic fistula. The sixth patient had a deforming fracture of the internal auditory canal that had produced severe hearing loss and constant unsteadiness because of the compression of the eight nerve, which had atrophied as a result. Half of the patients were diagnosed as having a central lesion. Only one of them benefited from the neurectomy. This patient had a large arterial loop within the internal auditory canal and the symptoms may have arisen because of friction of the vessel of the proximal portion of the vestibular nerve. The other five patients probably had a lesion at the level of eighth nerve brain-stem junction or central to it.