Flashback Fiday to Episode 200 : "Got SCIATICA? Try THIS Lumbar Gapping Maneuver" . Low Back Pain with Radicular Pain (ie sciatica, lumbar radiculopathy, foraminal stenosis), can often be caused by a narrowing of an area of the spine called the intervertebral foramen (IVF). The nerve roots branch off of the spinal cord at each vertebral level to the left and to the right, and in your lumbar spine, the nerve roots from segments L4 to S3 join together to from the SCIATIC NERVE. . A narrowed IVF ca