FOCUS
Neurosurg Focus 43 (2):E6, 2017W hile lumbar spondylolysis in the general adult population may reach as high as 5%-7% in select studies, 3,6,7,12,16,19,31,32,38,45,46,67 the actual incidence of spondylolysis in pediatric patients presenting with axial low-back pain may approach 50%.3,36 Numerous prior studies have described the presentation and management of lumbar spondylolysis, most commonly presenting at L-5 in up to 95% of cases and followed by L-4 in 5%-15%. 12,36,37,56 The vertebral segments of greatest lordosis and flexibility in the lumbar spine are the L4-5 and L5-S1 motion segments, where the points of greatest facet overhang occur and the greatest biomechanical forces are applied to the posterior elements.