Study design: Six cases are reported in which the clinical presentation of a prolapsed intervertebral disc was found to be caused by a localized venous plexus.
Objectives: To emphasize the fact that the clinical presentation of a localized plexus of epidural veins in the lumbar spine can resemble that of an acute disc prolapse.
Summary of background data: The finding of enlarged epidural veins during lumbar disc decompression is relatively common, but it is only recently that they have been implicated as the cause of the presenting symptoms.
Methods and results: Six individuals presented with severe pain in the lower back accompanied by sciatica, which had begun acutely. Physical examination in most of these patients showed the presence of neurologic signs in the affected leg. The initial clinical assessment was that of an acute prolapse of a lumbar disc. This diagnosis appeared to be borne out by the MRI scans, which demonstrated a "prolapsed disc" at the relevant level of the spine. However, at surgery, the intervertebral disc appeared to be relatively normal, but at the spine was found a large, localized plexus of epidural veins whose configuration matched the MRI image. The symptoms were relieved by decompression of the spine and ablation of the veins.
Conclusions: Any pathologic process in the lumbar spine compressing a nerve root can cause localized pain in the back accompanied by sciatica. Most of these conditions can be differentiated by means of an MRI scan. The MRI image of a localized plexus of epidural veins, however, closely resembles that of a prolapsed intervertebral disc, which may be diagnostically misleading.