Inner ear pathology following injury to the eighth cranial nerve and the labyrinthine artery

Inner ear pathology following surgical sectioning of the eighth cranial nerve and labyrinthine artery in humans is compared histologically to the pathology observed following severance of the eighth cranial nerve. The case in which both the eighth cranial nerve and the labyrinthine artery were surgically severed revealed severe pathologic changes in the cochlea, including complete loss of the organ of Corti and moderate pathologic changes in the fairly well-preserved vestibular end-organs. Interestingly, the endolymphatic sac appeared to be normal. However, the second case in which the eighth cranial nerve was sectioned but the labyrinthine artery was preserved revealed the organ of Corti and vestibular end-organs to be well preserved and normal. These findings suggest that the blood supply from the labyrinthine artery plays a major role in maintaining most of the structures in the inner ear except for the endolymphatic sac, and that the vestibular end-organs are more resistant than the organ of Corti to the effects of damage of the labyrinthine artery.