Search

Background Patients with bitemporal lobe epilepsy are generally not considered for surgical resection. Fortunately, responsive neurostimulation provides another avenue for the management of this challenging disease process. In conjunction with our epileptologist, we consider responsive neurostimulation for patients who have clinical features of temporal lobe epilepsy without clear localization on imaging and stereoelectroencephalography. Methods Here we describe our technique for implanting a responsive neurostimulator (NeuroPace, NeuroPace Inc., Mountain View, California) with depth electrodes monitoring the hippocampus and parahippocampus using stereotactic robotic guidance (ROSA, Medtech SA, Montpeillier, France). Results We have used this technique with 5 patients without morbidity. Four of 5 patients have received clinical benefit (Engel classification I–III). Promisingly, long-term seizure monitoring with use of the NeuroPace system has suggested lateralizing information on 3 of these patients that was not apparent on previous invasive monitoring. Conclusions Robotically implanted responsive neurostimulation is a safe and effective treatment for bitemporal epilepsy and can possibly lead to valuable diagnostic information to guide future surgical management in patients who previously were not considered candidates for resective or ablative surgery.

Robot-assisted stereotactic neurosurgery is an emerging technology with a growing range of applications. The ROSA system is a robotic stereotactic system that has been shown to be accurate in laboratory studies and large case series. The goal of this study was to examine the accuracy of the ROSA across different registration methods as well as different clinical applications. Sixteen patients with one hundred and seventeen stereotactic trajectories were examined. Accuracy was compared by measuring the distance between the trajectory target and the actual termination of the device as determined by imaging. Entry error and angular deviation were also measured. Variables included bone fiducials vs. laser facial scanning, the clinical indication for stereotactic surgery, and the effect of lead deflection on accuracy. Bone fiducials did not offer an accuracy benefit over laser facial scanning (mean target error 4.5–3.9 mm, p = 0.34) in these clinical scenarios. Laser interstitial thermal therapy, responsive neurostimulation, and stereo electroencephalography were equally accurate when placed by the ROSA (mean target error 4.4–4.3–4.0 mm, respectively, p = 0.69). Deflection did not affect lead accuracy (mean target error 4.4–3.9 mm, p = 0.11). Similar results are seen for entry error and angular deviation. ROSA is a highly accurate stereotactic system. Laser facial scanning provides the same accuracy as bone fiducials in these stereotactic applications. The ROSA is equally accurate across a wide spectrum of applications. The ROSA is effective at limiting lead deflection, and when it does occur, it does not impact target accuracy in a significant way.

OBJECTIVEThis study aimed to assess the safety and efficacy of MR-guided stereotactic laser ablation (SLA) therapy in the treatment of pediatric brain tumors.METHODSData from 17 North American centers were retrospectively reviewed. Clinical, technical, and radiographic data for pediatric patients treated with SLA for a diagnosis of brain tumor from 2008 to 2016 were collected and analyzed.RESULTSA total of 86 patients (mean age 12.2 ± 4.5 years) with 76 low-grade (I or II) and 10 high-grade (III or IV) tumors were included. Tumor location included lobar (38.4%), deep (45.3%), and cerebellar (16.3%) compartments. The mean follow-up time was 24 months (median 18 months, range 3–72 months). At the last follow-up, the volume of SLA-treated tumors had decreased in 80.6% of patients with follow-up data. Patients with high-grade tumors were more likely to have an unchanged or larger tumor size after SLA treatment than those with low-grade tumors (OR 7.49, p = 0.0364). Subsequent surgery and adjuvant treatment were not required after SLA treatment in 90.4% and 86.7% of patients, respectively. Patients with high-grade tumors were more likely to receive subsequent surgery (OR 2.25, p = 0.4957) and adjuvant treatment (OR 3.77, p = 0.1711) after SLA therapy, without reaching significance. A total of 29 acute complications in 23 patients were reported and included malpositioned catheters (n = 3), intracranial hemorrhages (n = 2), transient neurological deficits (n = 11), permanent neurological deficits (n = 5), symptomatic perilesional edema (n = 2), hydrocephalus (n = 4), and death (n = 2). On long-term follow-up, 3 patients were reported to have worsened neuropsychological test results. Pre-SLA tumor volume, tumor location, number of laser trajectories, and number of lesions created did not result in a significantly increased risk of complications; however, the odds of complications increased by 14% (OR 1.14, p = 0.0159) with every 1-cm3 increase in the volume of the lesion created.CONCLUSIONSSLA is an effective, minimally invasive treatment option for pediatric brain tumors, although it is not without risks. Limiting the volume of the generated thermal lesion may help decrease the incidence of complications.

Purpose: One of the most effective treatments for epilepsy is resection, but it remains underutilized. Efforts must be made to increase the ease, safety, and efficacy of epilepsy resection to improve utilization. Studies have shown an improved risk profile of stereoelectroencephalography (SEEG) over subdural grids (SDG) for invasive monitoring. One limitation to increased adoption of SEEG at epilepsy centers is the theoretical difficulty of planning a delayed resection once electrodes are removed. Our objective was to develop and present a technique using readily available neuronavigation technology to guide a cortical, non-lesional epilepsy resection with co-registration of imaging during invasive monitoring to imaging in an explanted patient, allowing for virtual visualization of electrodes. Methods: An example case taking advantage of the technique described above as an adjunct for an anatomically guided resection is presented with technical details and images. Results: Intraoperative neuronavigation was successfully used to virtually represent previously removed SEEG electrodes and accuracy could be easily verified by examining scars on the scalp, bone, dura and pia. Conclusions: The simple technique presented can be a useful adjunct to resection following SEEG. This may help increase the adoption of SEEG, even when resection is planned.

Intracranial lipomas represent approximately 1% of intracranial lesions generally felt to represent the abnormal persistence of the meninx primitiva and are commonly accompanied by various developmental brain abnormalities. We report a case of midline intracranial lipoma and evolving frontal lobe fluid-attenuated inversion recovery (FLAIR) abnormality concerning for glial neoplasm in a patient with intractable epilepsy. Our case shows evolving magnetic resonance imaging (MRI) features over two decades raising suspicion for low-grade neoplasm which was ultimately found to represent cortical dysplasia.

Deficiency of trophic factors relating to the survival of oligodendrocytes, combined with direct interactions with the immune system, are favored paradigms that are increasingly implicated in demyelinating diseases of the central nervous system. We and others have previously shown that Sema4A and H-ferritin interact through the T-cell immunoglobulin and mucin domain (Tim-2) receptor in mice. H-ferritin has been identified as the iron delivery protein for oligodendrocytes, whereas Sema4A causes a direct cytotoxic effect. However, the expression of Tim-2 has not been detected in humans. Here, we demonstrate that, similar to rodents, human oligodendrocytes undergo apoptosis when exposed to Sema4A and take up H-ferritin for meeting iron requirements and that these functions are mediated via the Tim-1 receptor. Moreover, we also demonstrate the ability of H-ferritin to block Sema4A-mediated cytotoxicity. Furthermore, we show in a series of pilot studies that Sema4A is detectable in the CSF of multiple sclerosis patients and HIV-seropositive persons and can induce oligodendrocyte cell death. Together, these results identify a novel iron uptake mechanism for human oligodendrocytes and a connection between oligodendrocytes and the immune system.

Hypothalamic hamartomas (HH) are benign tumors that can cause significant morbidity in adults as a cause of epilepsy, particularly gelastic seizures. Open and endoscopic resections of HH offer good seizure control but have high rates of morbidity and are technically challenging. Stereotactic radiosurgery has been an alternative treatment; however, it results in comparably poor seizure control. Recently, in children, stereotactic laser ablation has shown promise as a surgical technique that can combine the best features of both of these approaches for the treatment of HH. Here we present the first reported use of a frameless robot-assisted stereotactic system to treat an HH. The patient had failed two previous Gamma Knife radiosurgery treatments. Post-procedure he had a stable, but unintentional weight loss of 20 kg and a transient episode of hemiparesis the night of the operation. At six months postoperatively the patient remained seizure free. Stereotactic laser ablation may represent a new standard in the treatment of HH in adults, especially in those who have failed radiosurgery. Further study is warranted in this population to determine efficacy and safety profiles.