Postoperative striatal degeneration: a hitherto unrecognized impact of frontal disconnection surgery for drug-resistant epilepsy. Illustrative cases

Abstract

BACKGROUND Frontal disconnection surgery is a useful surgical option for patients with frontal epilepsy whose seizure onset zones are exceedingly large and thus are not amenable to conventional resective surgery. While it has the advantage of avoiding sequelae stemming from a large resection cavity, the impact of radical anatomofunctional disconnection of such a vast frontal region is not fully understood. OBSERVATIONS The authors have identified secondary degeneration in the striatum ipsilateral to the frontal disconnection surgery in two adult patients who had otherwise favorable postoperative outcomes following the surgery. On serial postoperative magnetic resonance imaging, the striatum showed transient restricted diffusion in the caudate head and rostral putamen around several weeks postoperatively and subsequent atrophy in the caudate head. The affected striatal regions (i.e., the anterior portion of the striatum) were congruent with the known fronto-striatal connectivity corresponding to the disconnected frontal regions anterior to the primary and supplementary motor areas. Both patients achieved 1-year seizure freedom without apparent disability related to the surgery. LESSONS The benign postoperative course despite the marked degenerative changes in the ipsilateral striatum supports the feasibility of the frontal disconnection surgery in otherwise inoperable patients with broad frontal epileptogenicity.

Addition of 1.5-Tesla arterial spin labeling magnetic resonance perfusion imaging to routine electroencephalography in pathophysiological diagnosis of first-onset generalized convulsive seizures in patients with dementia at neurological emergency

“…In the present study, ASL clearly depicted the involvement of deep structures such as the basal ganglia and thalamus, in addition to the hippocampus. In recent years, the relationship between epilepsy and the basal ganglia and thalamus has attracted significant attention from the perspective of the epileptic network [7,22,[28][29][30]. Thus, ASL findings are expected to provide new knowledge regarding the epileptic network in addition to the epileptogenic focus in dementia-related epilepsy.…”