Lidocaine injection into external carotid branches: provocative test to preserve cranial nerve function in therapeutic embolization.

Endovascular obliteration of hypervascular lesions of the head and neck has become clinically accepted, but it may cause stroke and peripheral cranial nerve palsy. By using a flow-controlled technique to deliver the materials and by knowing the vascular anatomy of the cranial nerves, these problems are less likely to occur. Occasionally, though, vascular anatomy is distorted by the lesion or is anomalous in its distribution. A provocative test of lidocaine injected into the appropriate artery seems to offer a functional test of whether the capillary bed will tolerate small-particle or liquid plastic occlusion. Twenty-six patients had various branches of their external carotid arteries challenged with lidocaine. Three developed transient palsies, and their treatments were modified. None of the 26 patients developed a complication of embolization.