Cervical pedicle agenesis: case report and bibliographic review.

The posterior arch defects of the cervical spine are rare, and they arise out of deviations of the normal intrauterine development of the spine (4-8 weeks of development). The defects range from a cleft to the total agenesis of the posterior arch, with a reported prevalence of 4% and 0.15%, respectively. The pedicle agenesis is most frequently found in C6. A diagnosis is usually made after a traumatic incident in a previously asymptomatic patient. 35% of a patient's current symptoms are associated with instability or translation of the impaired vertebral segments like headaches, chronic pain, and neurological impairment. The clinical and radiological findings of a patient with an unusual and complex cervical spine malformation are reported. These are rare entities and seldom require surgical treatment. It is imperative for spine surgeons to be aware of these anatomical abnormalities to avoid misinterpretation and thus inappropriate treatment, particularly in acute trauma patients.