Selective middle cerebral artery Wada tests as a part of presurgical evaluation in patients with drug-resistant epilepsies.

Abstract

To analyze the role of selective middle cerebral artery (MCA) Wada tests in the presurgical workup of patients with drug-resistant focal epilepsies. Twenty MCA Wada test procedures were performed to identify eloquent cortex (a) in nine patients with hemispheric lesions involving the motor cortex (connatal MCA infarct, n = 5; unilateral cortical dysplasia, n = 3; Rasmussen encephalitis, n = 1), (b) five patients with circumscribed neoplastic or nonneoplastic lesions adjacent to the motor cortex or classic language areas, and (c) for purely electrophysiologic reasons, in two patients with electrical status epilepticus in sleep (ESES). Sodium amobarbital and [99mTc]-HMPAO were simultaneously injected via a microcatheter into the distal M1 segment (n = 7), the inferior MCA trunk (n = 3), or into MCA branches (n = 10). Co-registered single-photon emission computed tomography (SPECT) and magnetic resonance imaging (MRI;n = 18) showed that sodium amobarbital did not reach the target area in three procedures. Temporary neurologic deficits occurred in 12 procedures. Eleven patients were operated on with the following surgical approaches: functional hemispherectomy, n = 3; partial or extended lesionectomy, n = 4; anterior temporal lobectomy, n = 1; and multiple subpial transsections, n = 3. Seizure freedom (Engel class I) was achieved in five patients. Selective MCA Wada tests can contribute to risk assessment concerning postsurgical motor deficits before functional hemispherectomy. Other indications are less clear: The identification of language areas is targeted primarily by electrical-stimulation mapping after subdural grid implantations, and selective MCA Wada tests in ESES patients yet have to be validated in larger patient groups.