PREOPERATIVE AND POSTOPERATIVE MAGNETIC-RESONANCE-IMAGING (MRI) FINDINGS OF RADICULOMENINGEAL ARTERIOVENOUS-MALFORMATIONS - IMPORTANT ROLE OF GRAVITY IN THE SYMPTOMS AND MRI

BACKGROUND The symptoms of radiculomeningeal arteriovenous malformatio ns (AVMs) are reported to be uniform, which suggests it to be a conus medullaris syndrome, and in fact, the lesions on magnetic resonance im aging (MRI) images usually include the conus medullaris. However, the reason why the conus medullaris is always involved in the lesion has n ot been discussed. METHODS We encountered seven patients with spinal r adiculomeningeal AVMs and operated on all of them. We evaluated the pr eoperative and postoperative MRI findings in these patients. Postopera tive MRI was followed ranging from 6-32 months (mean: 21 months) after surgery. RESULTS All of our patients showed swelling of the spinal co rd, including the conus medullaris, on the preoperative magnetic reson ance image. Postoperatively, MRI showed that the swelling of the spina l cord had resolved but that it had finally deteriorated into an atrop hic condition. In all of five patients who could be followed up using multiple postoperative MRI scans, sequential T-2-weighted images showe d that the most rostral level of areas with increased signal in the sp inal cord moved in a caudal direction with time. CONCLUSIONS This and the fact that the conus medullaris was included in the swelling of the spinal cord regardless of the level of the nidus in all our patients, suggested that gravity played an important role in the etiology of ra diculomeningeal AVM in these patients. (C) 1997 by Elsevier Science In c.