Open-loop stimulation studies have shown varying control of seizures with stimulation of different anatomical targets. A recent multi-institutional clinical study utilizing an external closed-loop stimulation system had promising results. A novel implantable closed-loop Responsive Neurostimulation System (RNS) (Neuropace, Inc., Mountainview, Calif., USA) consisting of a cranially implanted pulse generator, one or two quadripolar subdural strip or depth leads and a programmer is under testing in a prospective clinical trial. The RNS pulse generator continuously analyzes the patient’s electrocortigrams (ECoGs) and automatically triggers electrical stimulation when specific ECoG characteristics programmed by the clinician, as indicative of electrographic seizures or precursor of epileptiform activities, are detected. The pulse generator then stores diagnostic information detailing detections and stimulations, including multichannel stored ECoGs. The RNS programmer communicates transcutaneously with the implanted pulse generator when initiated by a clinician. The RNS programmer can download diagnostics and store ECoGs for review. The RNS programmer can then be used to program detection and stimulation parameters. In our current communication, we describe the selection criteria for implanting this system, the preparation of the surgical candidates as well as the surgical technique. We also present our preliminary results with 8 patients who had an RNS implanted. Seven patients (87.5%) had more than 45% decrease in their seizure frequency. The mean follow-up time in our series was 9.2 months. The implantation of a closed-loop stimulation system, in our experience, represents a safe and relatively simple surgical procedure. However, the efficacy of this new treatment modality remains to be determined in further multi-institutional, prospective clinical studies.
Several cases of congenital or acquired temporal encephaloceles have been reported in the literature as the causative mechanism of simple and/or complex partial seizures. In this report the authors describe a rare case of spontaneous parietal encephalocele presenting with simple partial seizures and progressively increasing contralateral upper-extremity motor deficit. The unusual anatomical location of an encephalocele associated with seizures and the delayed seizure onset represent distinctive characteristics in this case. Preoperative imaging included surface electroencephalography, computerized tomography, and brain magnetic resonance imaging. Frameless neuronavigation and intraoperative cortical mapping were used to aid resection of the encephalocele, and the dural and bone defects were reconstructed. The surgical outcome in this case was excellent, and the patient has remained seizure free. The pertinent literature is reviewed in this report.
ObjectStereotactic radiosurgery (SRS) with the Gamma Knife (GK) is a rapidly emerging surgical modality in the management of medically refractory idiopathic trigeminal neuralgia (TN). The current study examines the long-term outcome in patients with drug-resistant idiopathic TN who underwent GK surgery at the authors‘ institution.MethodsOne hundred and six consecutive patients (38 men and 68 women) with proven medically refractory idiopathic TN were included in this retrospective study. Their ages were 41–82 years (mean 72.3 years). All patients underwent SRS with prescribed maximal radiation doses ranging from 70 to 85 Gy. Isocenters 1–3 were used and plugging was used selectively. The follow-up period was 12–72 months (mean 34.3 months). The patients were divided into 2 groups according to their history of previous surgery.ResultsThe initial response rate in patients with no history of previous surgery was 92.9%; in those who had undergone previous surgery, the initial response rate was 85.7%. At the end of the 1st posttreatment year, an excellent outcome was achieved in 82.5% of patients who had not had previous surgery, and in 69.4% of those who had. The respective outcome rates for the 2nd posttreatment year were 78 and 63.5%, respectively. The most common complication was the development of persistent paresthesia, which occurred in 15.8% of patients with no previous surgery and 16.3% of those with previous surgery.ConclusionsStereotactic radiosurgery with the GK is a safe and effective treatment option for patients with medically refractory idiopathic TN.
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