Abstracts

Rationale: Intracarotid propofol procedure (Wada test) was been reported useful as a tool of presurgical evaluation for the determination of hemispheric language dominance. But the some of cases failed to achieve the conclusion because of the inter-individual difference of drug distribution due to the variation of vascular anatomy, presence of conscious disturbance or dysphagia cause to mislead the score of language task. For the accurate evaluation of hippocampal function on recent memory, we apply the super-selective injection of propofol from the proximal part of posterior cerebral artery that perfuse the hippocampus and parahippocampal gyrus under the use of endovascular neurosurgical technique (PCA-Wada). In this study we report the real procedure technique of PCA-Wada and the clinical results of the patients evaluated by PCA-Wada. Methods: Case series of consecutive 15 patients applied PCA-Wada from 2006 to 2016 in our institute for the presurgical evaluation of temporal lobe epilepsy (TLE). The indication of PCA-Wada was bellows; expected surgical resection included hippocampus in the dominant hemisphere and 1: TLE without hippocampal atrophy in MRI, 2: preserved verbal memory in revised Wechsler Memory Scale (WMS-R). The characteristics were bellows; eight male patients, aged 32.7 (21-57) years old. All patients were right-handed and presurgically diagnosed left TLE in the evaluation of comprehensive epilepsy monitoring unit in Tohoku University hospital. The number of cases without hippocampal atrophy were 14 and preserved verbal memory functions were nine.PCA-Wada was performed in endovascular neurosurgical suite. Patients were punctured the femoral artery and introduced guiding catheter to the cervical segment of dominant vertebral artery. Super-selective catheterization leaded the tip of microcatheter to the P1 segment of PCA that were just proximal part of P2 segment from which hippocampal artery rose. The 5mg of propofol prepared 1mg/ml was infused in 1 ml/sec infusion rate during the evaluation of hemianopsia. Immediately after the confirmation of hemianopsia that mean the propofol distribution to the PCA territory that include the calcarine artery, the verbal and non-verbal memory task was performed within the minutes by behavioral neurologist.The test was tried from bilateral side of PCA, and then we decided the the dominance of hippocampal verbal or non-verbal memories. Results: In all of the cases PCA-Wada were executed every task without conscious disturbance and confirmed hemianopsia after the injection of propofol. No complication with the procedure was occured.Laterality of the verbal memory function could be decided in all the cases. So we decided the high and low risk of functional deterioration after the hippocampal resection. All the cases of low-risk cases were treated hippocampectomy with or without anterior temporal lobe resection. Two of the six high-risk cases were avoided surgery and other two cases were treated by transection of hippocampus or parahippocampal gyrus. The score differences of verbal memory and delayed recall in WMS-R between pre-and-post surgery were -5.7pts, -1 pts in low-risk group and -22.5 pts, -17.0 pts in high-risk group, respectively. The scores in WAIS-R showed no significant change in both group. Conclusions: PCA-Wada can predict the postoperative verbal memory functions by evaluating the pure transient hippocampal function without contamination of other neurological deficit. Funding: None