[L4 crural neuralgia and disc hernia of the L4-L5 intervertebral foramen]

Discal L4 crural neuralgia is conventionally considered secondary to a hernia of the L3-L4 disc. Now, another source of discoradicular conflict exists on the path of the L4 root: hernia of the link canal of the L4-L5 canal through which the root leaves the rachidian canal. Of 27 discal neuralgias operated upon, 9 were linked to a hernia of the L3-L4 disc, while 18 were secondary to a hernia of the L4-L5 foramen, that is 2 foramina hernias for 1 "intrarachidian" hernia. The diagnostic difficulties resulting from foramina hernias probably reflect a rarity that is more apparent than real. The etiology of crural neuralgia is conventionally sought at the L3-L4 disc. This search is often unsuccessful: one speaks of "essential crural neuralgia". The scanner provides the only certain way of revealing foramina hernias, and will probably detect increasing numbers and thus reduce the number of "idiopathic crural neuralgias".