spinal or neurogenic claudication is not due to lack of blood supply, but rather it is caused by nerve root compression or stenosis of the spinal canal, usually from a degenerative spine, most often at the "l4-l5" or "l5-s1" level. this may result from many factors, including bulging disc, herniated disc or fragments from previously herniated discs (post-operative), scar tissue from previous surgeries, osteophytes (bone spurs that jut out from the edge of a vertebra into the foramen, the opening through which the nerve root passes). in most cases neurogenic claudication is bilateral, i.e. symmetrical.