Spondylolysis of the upper lumbar spine: Radiological features

To elucidate the radiological features of spondylolysis of the three upper lumbar vertebrae, review of radiology reports during an 8-year period was p erformed. Among 17 levels of defects in 14 patients, nine were unilateral. Among 25 defects, nine had an atypical course. In eight of nine atypical de fects, the direction was vertical at the inferolateral aspect, and horizont al at the superomedial aspect. The spondylolysis of the upper lumbar spine is often unilateral and the course of the defect is frequently atypical. (C ) Elsevier Science Inc., 2000.