Congenital absence of a cervical spine pedicle: clinical and radiologic findings.

Congenital absence of a cervical pedicle is an unusual disorder with potentially confusing clinical and radiologic manifestations. A review of the previously reported 42 cases as well as 13 new cases is presented. Congenital absence of a cervical pedicle was an incidental finding in 10 of the 55 total patients (age range, 3-65 years; mean 31 years). The remainder presented with an array of symptoms; the most common was cervical pain (31 patients), often after trauma (19/31). Neurologic examination was normal in the majority (65%) of patients. The most common neurologic finding, in an additional 19% of patients, was isolated diminished sensation in an upper extremity. Imaging included conventional radiographs, tomograms, myelograms, and CT. The typical radiologic triad of findings included (1) the false appearance of an enlarged neural foramen owing to the absent pedicle; (2) a dysplastic, dorsally displaced ipsilateral articular pillar and lamina; and (3) a dysplastic ipsilateral transverse process. The spectrum of this disorder also included absence of the ipsilateral pillar in four of 55 patients and absence of the entire ipsilateral neural arch in five of 55 patients. Other osseous anomalies were present in 28 (51%) of 55 cases. In 10 of 55 cases, initial misdiagnosis resulted in inappropriate therapy, with a poor clinical outcome after therapy in three cases. Conservative therapy was the only successful management in all cases in which follow-up information was available, with the exception of one patient who had partial improvement after surgery. Careful analysis of radiologic images and knowledge of the specific findings of absent cervical pedicle should decrease the potential for misdiagnosis and inappropriate, potentially harmful therapy.