RADIOLOGY MONITORING

Introduction

The rise of interventional radiology over the last 10 years has lead to the performance of increasingly complex and difficult endovascular procedures. These have replaced or complimented some standard neurosurgical and vascular procedures that have previously used intra-operative monitoring such as berry aneurysm treatment. Arterial stenting involving the carotid and other arteries is becoming increasingly available and popular.

Indications

IONM may be useful in monitoring endovascular procedures in which there is a risk of distal embolus, rupture or occlusion; for which there is a corrective therapy such as anticoagulation or surgery; and for which there is a reason that neural status can not be easily followed clinically such as a need to sedate or anesthetize the patient. Berry aneurysm coiling often satisfies these needs. Carotid stenting has been shown to release larger numbers of distal emboli than endarterectomy, but there is contradictory evidence of the clinical importance of this and the benefit of monitoring in this situation. Intraoperative TCD, which some critics suggest is like 'closing the barn door after the horse is out' may play a more complex role in predicting the likelihood of further more devastating events later on (the remainder of the herd).

Modalities Used

SEP, EEG, TceMEP, BAER, TCD

R. O'Brien MD

Select References

Liu, A. Y.; Lopez, J. R.; Do, H. M.; Steinberg, G. K.; Cockroft, K. & Marks, M. P. (2003), 'Neurophysiological monitoring in the endovascular therapy of aneurysms.', AJNR Am J Neuroradiol 24(8), 1520--1527.

Rohde, V.; Will, B. E.; Hahn, G.; Bien, S. & Zentner, J. (1999), '[Motor evoked potentials during embolization of arteriovenous malformations for the detection of ischemic complications]', Zentralbl Neurochir 60(2), 74--80.

Sala, F.; Niimi, Y.; Berenstein, A. & Deletis, V. (2001), 'Neuroprotective role of neurophysiological monitoring during endovascular procedures in the spinal cord.', Ann N Y Acad Sci 939, 126--136.

Sala, F.; Niimi, Y.; Krzan, M. J.; Berenstein, A. & Deletis, V. (1999), 'Embolization of a spinal arteriovenous malformation: correlation between motor evoked potentials and angiographic findings: technical case report.', Neurosurgery 45(4), 932--7; discussion 937-8.