Kimmerle's anomaly as a possible causative factor of chronic tension-type headaches and neurosensory hearing loss: case report and literature review.

Kimmerle's anomaly also known as ponticulus posticus is a common anatomical variation of the atlas, the first cervical vertebra. It is the product of the complete or incomplete ossification of the posterior atlanto-occipital membrane over the vertebral artery groove resulting in the formation of a foramen (arcuate foramen) containing the vertebral artery and the posterior branch of the C-1 spinal nerve. This variation has been associated with vertebro-basilar insufficiency symptoms, various types of headaches, and acute hearing loss. The aim of the present study is to substantiate whether Kimmerle's anomaly is the possible cause of chronic tension-type headaches and neurosensory-type hearing loss in a patient with a known history of headaches and accompanied unilateral hearing loss. The headaches demonstrated the characteristics of the chronic tension-type; the audiometric investigation concluded the hearing loss to be of the neurosensory type; whereas, the imaging examinations revealed the existence of a partial osseous bridge, that is an incomplete arcuate foramen (ponticulus posticus or Kimmerle's anomaly) on the upper surface of atlas. Both the clinical and the radiological findings of this case are indicative of a possible connection between Kimmerle's anomaly and the manifestation of chronic tension-type headaches and neurosensory-type hearing loss.