Patient of Congenital Absence of a Lumbar Pedicle With Nerve Root Anomaly Presenting With Ipsilateral Foraminal Stenosis by Vertebral Fracture.

Patients with congenital absence of a lumbar pedicle and nerve root anomaly presenting with ipsilateral foraminal stenosis are extremely rare. An 80-year-old man had low back and right thigh pain. Radiographs and computed tomography (CT) showed L3 vertebral body fracture and the absence of the right L3 lumbar pedicle. He was diagnosed with L2-L3 right foraminal stenosis caused by an L3 vertebral fracture and underwent lumbar fusion at L2-L3 and L3-L4. Intraoperatively, we confirmed that an anomalous nerve root was divided from the right L2 nerve root near the dorsal root ganglion (DRG). Patients with congenital absence of a lumbar pedicle are less prone to ipsilateral foraminal stenosis because they theoretically have a large space in the foramen. This rare case was caused because of additional instability due to vertebral fracture under the condition of a nerve root anomaly and lumbar degeneration.