Percutaneous needle evaluation of intradural extramedullary lesions of the lumbar spine.

A total of eight patients in whom five intradural extramedullary lesions and three epidural lesions were present were evaluated by percutaneous needle biopsy. In four patients the level of aspiration biopsy was determined using the initial myelogram and in those patients fluoroscopic guided percutaneous needle biopsies were performed. Three of these patients had large intradural extramedullary masses (above 1 cm); one patient had an epidural lesion. Diagnostic material was obtained in all cases (medulloblastoma, astrocytoma, small cell carcinoma, adenocarcinoma). Immediate post procedure CT and clinical followup showed no complications. In three patients with small lesions (below 1 cm), post myelographic CT was used to determine the level of aspiration. Post myelographic CT showed an intradural extramedullary mass in one patient and epidural lesions in two cases. Plain CT showed a high attenuation lesion in one patient. CT guided percutaneous needle biopsies in these four patients yielded diagnostic specimens (neurofibroma, uroepithelial carcinoma, hematoma, Thorotrast deposit). Clinical follow up showed no complications. Our experience indicates that percutaneous needle biopsy of intradural extramedullary and epidural lesions of the lumbar spine is safe and efficacious. Depending upon the size of the lesions, myelography or CT can be utilized to determine the level of aspiration.