Herniated intervertebral disk: a plea for a more uniform terminology.

In the original description of herniated intervertebral disk by Mixter and Barr [1), the term used was rupture of the inter-vertebral disk. However, with the passage of time, this term, although used frequently by surgeons, has become meaningless. A rupture of the disk is a common finding at autopsy when the disks are examined, but ruptures are not necessarily associated with herniation of the nucleus pulposus. Nowadays we use a number of techniques to study the lower back, including plain films, CT, MR, and myelography, which today more often than not is followed by CT examination. At Massachusetts General Hospital, CT is done after practically 1 00% of the lumbar myelograms, and therefore CT myelography has become routine. With all these diagnostic procedures, we are able to obtain a considerable amount of information as to what is happening in the intervertebral disks and the spinal canal, and we should aim at being as accurate as possible in our final diagnosis of the pathologic process that is present in each case. Disk disease is an extremely common disorder, and perhaps this has led to the variety of terms frequently used, sometimes inappropriately, or at least not in adherence with proper imaging or pathologic criteria. The terms used frequently today are ruptured disk, her-niated intervertebral disk, herniated nucleus pulposus, protruding disk, bulging disk, prolapsed disk, extruded disk, and, finally, sequestered disk. Some of these terms can be understood without confusion, but some of the others cannot. As mentioned before, the term rupture is vague and should not be used to deal with surgical problems. Herniated intervertebral disk or herniated nucleus pulposus is the clearest term, well understood by everyone. It can be used simply, or it can be modified to clarify a specific feature in individual cases. From the radiologic point of view, hernia-tion can be diagnosed if the disk contour has a focal bulge or protrusion. Wherever a focal bulge of the disk is present, disk herniation can be diagnosed confidently. This does not mean that the herniation is a surgical lesion, for it actually could be small. The posterior herniation could be to the right or to the left of the midline (as it is most frequently) or in the center. The herniation could be anterolateral, where it would never affect the nerve roots, or it could be posterolateral or extra-foramina! but capable of compressing the nerve roots, or it …