Congenital absence of a lumbar pedicle presenting with contralateral lumbar radiculopathy

The authors describe a rare case of a congenital absence of the right L5 pedicle in a 54-year-old man presenting with low back pain and radicular pain of his left leg. Plain x-ray films, computed tomography scan (CT) after myelography, and three-dimensional CT revealed the absence of the L5 pedicle and anomaly of the L4-L5 facet joint on his right side. On the left side, there were severe degenerative changes that were thought to be the result of an overload and instability. The degenerative changes led to late-onset neurologic impairment of the contralateral side, which was treated with spinal fusion. To our knowledge, this is the first report of contralateral symptoms due to unilateral defect of the facet joint accompanied by aplasia of a pedicle.