The mundane malady sciatica has been known to physicians since
antiquity.1 It is pain that radiates from the buttock downward along the
course of the sciatic nerve,2 but the term has been used indiscriminately for
a variety of back and leg symptoms. Although sciatica has several causes, Mixter
and Barr extended previous observations to establish in 1934 that the principal
source is compression of a lumbar nerve root by disk material that has ruptured
through its surrounding annulus (see the Glossary).3 Neuroradiologic studies affirm
that 85% of cases of sciatica are associated with a disk disorder.