Ultrastructural changes of the cochlea after oral and maxillofacial firearm wounds

There have been reports that maxillofacial firearm wounds could induce hearing loss. The effects on the ultrastructure of the cochlea and cochlear nerves after oral and maxillofacial firearm wounds are still unclear. This experiment investigates the ultrastructural changes of the cochlea and cochlear nerve after oral and maxillofacial firearm wounds.

Twenty dogs were wounded by steel spheres or detonators to establish animal models of oral and maxillofacial firearms wound. At different times after trauma, the wounds were examined and the specimens of the cochlea and cochlear nerve were taken to study the ultrastructural changes.

The ultrastructural changes of the cochlea and cochlear nerve at 1 hour after trauma were cilia disorganization, edema of the nerve, and mitochondrial denaturalization. At 6 hours, there was extensive degeneration in the cochlea and cochlear nerve, cilia falling off of hair cells, and dissolution of the nerve sheath structure.

The ultrastructure of the cochlea and cochlear nerve after injury is severe, but in the early period the injury is reversible.