Cauda equina arachnoiditis. A correlative clinical and roentgenologic study.

A series of 93 consecutive patients whose myelograms were reported as showing arachnoiditis were studied, and correlations between the radiographic appearance and the clinical and surgical findings were tabulated. All but 1 patient had had either lumbar disc surgery and/or Pantopaque myelography. The study led to a classification of such roentgenogram changes which revealed that the majority of patients studied did not have the usual adhesive arachnoiditis, but the picture they projected was more commonly due to spinal stenosis, extraarachnoid dye injection, extradural scar, etc. Only 1 patient of the 93 presented the classic severely disabling paraparesis, intractable pain, and loss of bowel and bladder functions commonly ascribed to adhesive arachnoiditis. The presence of such myelographic changes need not deter necessary surgery for coexisting disc pathology, nerve root entrapment, or spinal stenosis. In only a small percentage of these patients could the symptoms be attributed to the arachnoiditis changes seen in the myelogram.