Congenital fusion C0-C2 associated with spondylolysis of C2.

This is the report of a very rare malformation at the cranio-cervical junction, including congenital occipito-cervical fusion C0-C2, spondylolysis of C2, and hypoplasia of the right vertebral artery. The malformation itself is part of a Klippel-Feil syndrome with sensory-neural hearing loss on the left side, congenital high thoracic scoliosis, rib agenesis on the right side, and kidney malformations on both sides.