Because of its unique anatomy, specific diseases and lesions arise in the upper cervical spine, which differ widely from the rest of the spine. During the last two decades standardised diagnostic and therapeutic algorithms have been defined for most of the craniocervical pathologies often occurring in combination with an underlying disease requiring surgical intervention as well. On the other hand there are some very rare phathological alterations: about 20% of the patients suffering from neurofibromatosis type I develop spinal deformities. These are mostly found in the thoracic and lumbar spine (dystrophic/non-dystrophic type). In rare cases the dystrophic neurofibromatosis type I involves the upper cervical spine leading to bizarre deformities endangering the spinal cord. An aggressive, timely and combined operative therapy is necessary. Patients with Down syndrome should be investigated regularly for affections of the upper cervical spine. Though only in about 1% of all patients with Down syndrome do instabilities require surgical intervention, the upper cervical spine should be screened on a regular basis, since neurological changes due to the pathognomy of the underlying disease often remain undetected for a long time. The operative therapy of the instable os odontoideum in Down syndrome follows the general principles of this pathoanatomical variation. Even though the Klippel-Feil syndrome is generally not linked with neuropathological findings, rare associated deformities of the upper cervical spine should be excluded by proper diagnostic procedures.
