Intermittent cauda equina compression due to narrow spinal canal

✓ Five patients with intermittent claudication due to compression of the cauda equina in the presence of lumbar spinal canal stenosis or midline intervertebral disc protrusion are described. The characteristic myelographic evidence was complete obstruction during extension of the spine and release of the block with flexion. The cause of this syndrome is considered to be intermittent bulging of the ligamentum flavum into a narrow spinal canal so as to compress the cauda equina during extension of the back.