Abstracts

Rationale: Wada test is considered “gold standard” in language lateralization and presurgical memory assessment for patients with refractory epilepsy considering epilepsy surgery. During the procedure a short acting anesthetic such as amobarbital or methohexital is injected into the internal carotid to selectively inhibit one hemisphere, then neuropsychological testing is performed to lateralized patient's speech and assess memory.

Adverse effects can occur in up to 10% of patients with effects including seizures, status epilepticus, vasospasm, encephalopathy etc. Most critical adverse event involves accidental delivery of the anesthetic drug to the brainstem via a fetal-type Posterior Communicating Artery (PCA) or patent flow in the Posterior Communicating Artery which can cause cardiac arrest. If such a connection is identified prior to the injection of the anesthetic during the angiogram the test is aborted to avoid a potential life threatening complication, depriving the treatment team of an important tool necessary for presurgical evaluation.

Methods: Three consecutive patients with a fetal-type PCA had their WADA test safely performed by our Interventional Neurologist by selectively injecting the anesthetic into the M1 portion of the Middle cerebral artery (MCA).

Patient 1 : 24-year-old male with refractory right temporal lobe epilepsy.
Right ICA injection showed a strong flow into the PCA. Using a Velocity microcatheter positioned in M1 segment of MCA 5mg of Methohexital was administered safely.

Patient 2 : 37-year-old female with refractory right temporal lobe epilepsy.
Right ICA injection showed opacification of PCA. Using a Velocity microcatheter position in M1 segment of the MCA 100mg of Amobarbital was administered safely.

Patient 3: 27-year-old male with refractory epilepsy s/p left temporal lobectomy (age5) with recurrence of seizures being evaluated for repeat surgery.
Right ICA injection showed flow into the PCA and reflux in basilar artery. Using a microcatheter in the M1 segment of Right MCA 100mg of Amobarbital was injected. After a 20 min washout the M1 segment of the Left MCA was injected with 100mg of Amobarbital.

Results: Three consecutive patients who had a fetal-type PCA underwent WADA testing by injecting the M1 segment of the MCA. In two of the tests the anesthetic agent was Amobarbital and Methohexital in the third. Patients developed transient contralateral hemiplegia and slowing on the EEG and successfully completed the WADA testing without any complications.

Conclusions: Superslective injection of the M1 segment of the Middle cerebral artery can be considered to safely complete the WADA testing for language lateralization in patients when accidental flow into the posterior circulation is identified, instead of aborting the test.

Funding: Please list any funding that was received in support of this abstract.: none.