Sequential injections of amobarbital sodium and lidocaine for provocative neurologic testing in the external carotid circulation.

PURPOSE: To present the results of a protocol for embolization in the external carotid territory that includes provocative testing with amobarbital sodium and lidocaine.
METHODS: Provocative testing with sequential intraarterial injections of amobarbital sodium and lidocaine was done before embolization of 66 vascular pedicles in 26 patients with the following pathologic disorders: 8 meningiomas, 7 paragangliomas, 5 dural arteriovenous fistulas, 3 angiofibromas, 1 endolymphatic sac carcinoma, 1 metastatic renal carcinoma, and 1 Rendu-Osler-Weber syndrome. Findings during provocative testing and any postembolization deficits were recorded.
RESULTS: Of the 66 vascular pedicles tested, only 1 showed positive findings on an amobarbital test, in which the patient had transient numbness in the contralateral leg. Results of lidocaine tests were positive, in 7 cases, in which cranial nerve deficits were suspected on the basis of anatomic findings. All deficits resolved within 15 minutes. If results of amobarbital or lidocaine tests were positive, large particles or coils were used for embolization. Otherwise, small particles or liquid agents were used. There were no complications after embolization.
CONCLUSIONS: Provocative testing with amobarbital can reveal dangerous anastomoses. Testing with lidocaine can show vascular supply to the cranial nerves. With the use of appropriate protocols, embolization in the external carotid territory can be done with minimal risk.