Estimating Lumbar-Puncture Depth in Children

To the Editor: Many procedures performed in children use predictive formulas to enhance technical efficacy. To increase the accuracy with which lumbar puncture is performed and to minimize the rate of traumatic puncture, we conducted a 12-month prospective analysis of children in whom the procedure was performed during the evaluation of an acute illness. Each lumbar puncture was performed by positioning the child in the right lateral decubitus position, maximally flexed at the waist and neck. The spinal needle was inserted perpendicular to the plane of the back in the L-3-to-L-4 vertebral interspace until reflux of cerebrospinal fluid occurred. After.