Remote Ischemic Conditioning Alters Methylation and Expression of Cell Cycle Genes in Aneurysmal Subarachnoid Hemorrhage.

BACKGROUND AND PURPOSE: Remote ischemic conditioning (RIC) is a phenomenon in which short periods of nonfatal ischemia in 1 tissue confers protection to distant tissues. Here we performed a longitudinal human pilot study in patients with aneurysmal subarachnoid hemorrhage undergoing RIC by limb ischemia to compare changes in DNA methylation and transcriptome profiles before and after RIC. METHODS: Thirteen patients underwent 4 RIC sessions over 2 to 12 days after rupture of an intracranial aneurysm. We analyzed whole blood transcriptomes using RNA sequencing and genome-wide DNA methylomes using reduced representation bisulfite sequencing, both before and after RIC. We tested differential expression and differential methylation using an intraindividual paired study design and then overlapped the differential expression and differential methylation results for analyses of functional categories and protein-protein interactions. RESULTS: We observed 164 differential expression genes and 3493 differential methylation CpG sites after RIC, of which 204 CpG sites overlapped with 103 genes, enriched for pathways of cell cycle (P<3.8×10(-4)) and inflammatory responses (P<1.4×10(-4)). The cell cycle pathway genes form a significant protein-protein interaction network of tightly coexpressed genes (P<0.00001). CONCLUSIONS: Gene expression and DNA methylation changes in aneurysmal subarachnoid hemorrhage patients undergoing RIC are involved in coordinated cell cycle and inflammatory responses.

Long-Term Evaluation of Changes in Operative Technique and Hardware-Related Complications With Deep Brain Stimulation.

BACKGROUND: Deep brain stimulation is the most frequent neurosurgical procedure for movement disorders. OBJECTIVE: While this elective procedure carries a low-risk profile, it is not free of complications. As a new procedure, the pattern of complications changed with experience and modification of surgical technique and equipment. METHODS: This review analyzes the most common hardware-related complications that may occur and techniques to avoid them. It is a retrospective review of 432 patients undergoing 1077 procedures over a 14-year period by one surgeon with emphasis on the analysis of surgical technique and the changes over time. Comparisons were made pre and postimplementation of different surgical techniques over different time periods. The epochs relate to the learning curve, new equipment, and new techniques. RESULTS: Overall lead revision was observed at 5.7%, extension revision at 3.2%, infection rate at 1.2%, infarct without intracerebral hemorrhage at 0.8%, and intracerebral hemorrhage at 2.5% with a permanent deficit of 0.2%. An analysis and change in surgical technique which involved isolating the lead from the skin surface at both the cranial and retro-auricular incision also demonstrated a substantial decrease in lead fracture rate and infection rate. There was no mortality. CONCLUSION: This large series of patients and long-term follow-up demonstrates that risks are very low in comparison with other neurosurgical procedures, but DBS is still an elective procedure that necessitates extensive care and precision. In a rapidly evolving field, attention to surgical technique is imperative and will keep rates of complications at a minimum.

An evaluation of hardware and surgical complications with deep brain stimulation based on diagnosis and lead location.

INTRODUCTION: Deep brain stimulation is the most frequently performed neurosurgical procedure for movement disorders. This procedure is well tolerated, but not free of complications. Analysis of hardware complications based on patient diagnosis and lead location could prove valuable in recognizing potential pitfalls and patients at higher risk. METHODS: This review analyzes the most common surgery-related complications that may occur based on diagnosis and lead location. Patients were categorized based on diagnosis - Parkinson's disease (PD), dystonia, and essential tremor (ET) - as well as by lead location - subthalamic nucleus (STN), globus pallidus interna (GPi), and ventral intermediate nucleus of the thalamus (Vim). It is a retrospective review of 326 patients undergoing 949 procedures over a 10-year period by one surgeon. Fisher's exact test and χ(2) test were employed and multivariate logistic regression analysis was performed to identify the significant variables of correlation. RESULTS: Overall lead revision was observed at 5.7%, but was observed at 11.9% of GPi lead placements, and 10.7% of dystonia patients with only 4.6% of STN lead placements. Total extension revision was at 2.5%, but observed at 5.3% for dystonia patients and at only 1.4% for ET patients. Overall infection rate was at 1.9% with the highest rate observed in dystonia and ET patients. Postoperative complications with hardware, erosion, infection, and delayed stimulation failure were observed more often with ET and dystonia than with PD. This difference was statistically significant between dystonia and PD (p < 0.03) but not between the other disease entities (p > 0.05). On multivariate analysis, age and gender had no correlation with these complications. PD had significantly fewer complications on forward selection regression analysis (p = 0.004). Asymptomatic intracerebral hemorrhage was at 2.5% with the majority in Vim and none observed in GPi placements. There was only one symptomatic hemorrhage with a permanent deficit. Infarcts were observed at 0.8%. There were no mortalities. CONCLUSION: This large series of patients and long-term follow-up demonstrate that risks of complications are not universal among movement disorder patients. Diagnosis and lead location are important risk stratification factors in determining complications.

Contributing factors to surgical site infections.

Surgical site infections (SSIs) are the most common nosocomial infections. These complications lead to revision surgery, delayed wound healing, increased use of antibiotics, and increased length of hospital stay, all of which have a significant impact on patients and the cost of health care. Such intraoperative factors as proper skin preparation, adherence to sterile technique, surgical duration, and traffic in the operating room contribute more to SSIs than do patient-related risk factors such as diabetes mellitus, obesity, and preexisting colonization with methicillin-resistant Staphylococcus aureus. Surgeons have a responsibility to understand the current evidence regarding the factors that affect the rates of SSIs so as to provide the highest level of patient care.

Intracarotid amobarbital procedure for epilepsy surgery.

The intracarotid amobarbital procedure (IAP) has been used for more than half a century to determine language dominance and to assess risk for amnesia after anterior temporal lobectomy. However, because of the risk associated with angiography and the development of noninvasive techniques, the need for the IAP when evaluating patients for epilepsy surgery can now be questioned. The purpose of this review is to examine the clinical indications and efficacy of the Wada test in the preoperative evaluation of epilepsy surgery candidates. This article summarizes a debate that took place during the 2009 American Epilepsy Society (AES) annual course.

Spinal cord injury induced by a cervical spinal cord stimulator.

OBJECTIVE: The use of cervical spinal cord stimulators for the treatment of refractory neck and upper extremity pain is widely accepted and growing in use as a treatment modality. This case highlights a previously unreported potential complication of spinal cord stimulators. METHODS: Analysis of a patient with a cervical spinal cord stimulator presenting with a spinal cord injury. Patient was followed from presentation in the emergency room until 1-year follow-up in the office. RESULTS: The patient in this case presented after a fall and sustained a cervical spinal cord injury induced by the electrodes of her spinal cord stimulator working as a space occupying mass. CONCLUSION: As more patients are undergoing implantation of spinal cord stimulators we must be aware of the long-term risks that can be encountered.

Simultaneous use of neurostimulators in patients with a preexisting cardiovascular implantable electronic device.

OBJECT: Neurostimulation is widely accepted for the treatment of refractory Parkinson's disease, essential tremor, and chronic pain. The presence of a cardiovascular implantable electronic device (CIED) might be considered a contraindication for neurostimulators due to the possible interaction between the two devices. The purpose of this study is to report the feasibility and safety of concomitant use of neurostimulators and CIED, and to review surgical and clinical precautions needed to avoid possible interference between the two systems. METHODS: A retrospective institutional review board approved chart review of six patients having both a neurostimulator(s) and a CIED was performed. Diagnosis included Parkinson's disease (two) and intractable pain (four). All implantable cardiac devices were set on bipolar sensing mode and bipolar stimulation was chosen for the neurostimulators. In general, both systems were implanted at sites seven inches apart. Electrocardiogram monitoring was observed throughout implantation. Patients were followed up for a mean period of 31.7 months (ranging from 14 to 67 months). An extensive chart review was done and cases from previous reports were compiled. RESULTS: In all six patients, no acute events occurred during surgery with no interaction or interference noted during implantation of the second device. Subsequent follow-up visits continued to exhibit a lack of interference between the two systems, including normal electrocardiogram studies. Both systems were noted to function at optimal levels. An extensive literature review revealed 57 unique cases previously published reporting the simultaneous use of neurostimulators and a CIED in the same patient. A table summarizing previously cited cases from the literature is provided. CONCLUSION: The concomitant use of neurostimulator(s) and permanent pacemaker(s) can be safely performed. Permanent pacemaker should not be considered a general contraindication for neurostimulation therapy. Current literature lacks evidence to determine the safety of concomitant use of neurostimulator(s) and implantable cardioverter defibrillator(s).

Presigmoid Transpetrosal Approach for Superficial Temporal Artery to Distal Posterior Cerebral Artery Bypass and Trapping of Aneurysm.

BACKGROUND AND IMPORTANCE: Aneurysms of the posterior cerebral artery (PCA) are uncommon, estimated at less than 1% of all cerebral aneurysms, and less than half occur distal to the P1/2 junction. Unfortunately, the conventional bypass approach for PCA aneurysms-primarily occipital artery to distal PCA cortical branches-has a history of unsatisfying results. CLINICAL PRESENTATION: A 42-yr-old female presented with Fisher 3 Hunt-Hess 2 subarachnoid hemorrhage secondary to ruptured distal PCA aneurysm. She was initially evaluated by the endovascular service, but due to recent subarachnoid hemorrhage, endovascular treatment with flow diversion and/or vessel sacrifice was felt to be relatively contraindicated and the patient was referred for surgical evaluation for possible bypass. The patient subsequently underwent surgery for trapping of aneurysm and concomitant superficial artery to distal PCA bypass. CONCLUSION: A novel approach for the treatment of a ruptured distal PCA aneurysm is described, consisting of posterior transpetrosal exposure and division of the tentorium with superficial temporal artery to P3 bypass.

Role of Intravenous Tissue Plasminogen Activator in Acute Ischemic Stroke with Large Vessel Occlusion.

OBJECTIVE: The goal of the present study was to determine the safety and efficacy of intravenous tissue plasminogen activator (IVT) in patients with acute ischemic stroke (AIS) with large vessel occlusion (LVO) undergoing mechanical thrombectomy (MT). METHODS: We performed a retrospective analysis of prospectively collected data gathered during a 3-year period for all our patients with AIS and LVO. We analyzed the stroke outcomes and complications between patients who had received a combination of IVT and MT and those who had undergone MT only. Standardized selection criteria, including the uniform use of perfusion imaging, were used for selection for MT, irrespective of IVT administration. RESULTS: Of the patients who had received IVT, 10% had had successful reperfusion found at initial angiography and did not require MT. A door-to-puncture time within 1 hour of presentation was achieved in 19% of both groups. IVT+MT was not associated with an increased incidence of intracranial hemorrhage (IVT+MT, 47.1%; MT, 49%). Of the 73 patients in IVT+MT group, 8 had developed access-site hematomas compared with 9 of the 95 patients in the MT group (28.6% vs. 26.5%; P = 0.85). The IVT+MT group had a lower proportion of patients with a modified Rankin scale score of 5-6 at 90 days compared with the MT group (36% vs. 56%; P = 0.024). Both groups showed statistically similar proportions of patients with a Thrombolysis in Cerebral Infarction scale score of ≥2c (IVT+MT, 50%; MT, 43%; P = 0.58). The IVT+MT group had a greater proportion of patients with Thrombolysis in Cerebral Infarction scale score of 2c (IVT+MT, 29.6%; MT, 16.8%; P = 0.068). CONCLUSIONS: Administration of IVT before MT to patients with AIS with LVO resulted in reperfusion before MT in 10% of patients, reduced the incidence of mortality and severe disability at 90 days, did not affect the door-to-puncture time, and was associated with a similar incidence of systemic and intracranial hemorrhage compared with MT only.

Updates in the management of cranial dural arteriovenous fistula.

Dural arteriovenous fistula (dAVF) accounts for approximately 10% of all intracranial vascular malformations. While they can be benign lesions, the presence of retrograde venous drainage and cortical venous reflux makes the natural course of these lesions aggressive high risk of haemorrhage, neurological injury and mortality. Endovascular treatment is often the first line of treatment for dAVF. Both transarterial and transvenous approaches are used to cure dAVF. The selection of treatment approach depends on the angioarchitecture of the dAVF, the location, the direction of venous flow. Surgery and, to a lesser extent, stereotactic radiosurgery are used when endovascular approaches are impossible or unsuccessful.

Increased Rate of Successful First Passage Recanalization During Mechanical Thrombectomy for M2 Occlusion.

BACKGROUND: Mechanical thrombectomy (MT) is the standard of care for the treatment of acute ischemic stroke (AIS) caused by anterior circulation large-vessel occlusion. However, the true safety and efficacy of MT in medium-size vessel occlusions such as the M2 segment of the middle cerebral artery have yet to be completely defined. In this study, we analyze the safety and efficacy of MT in M2 occlusions compared with M1 occlusions. METHODS: A retrospective analysis was performed of patients with AIS secondary to M1 and M2 occlusions between 2011 and 2018. The inclusion criteria were 1) AIS secondary to M1 or M2 occlusion, 2) MT performed by stentrieval technique alone, aspiration technique, or combined stentrieval-aspiration techniques. Basic patient characteristics, number of passages, first passage recanalization success (≥TICI [Thrombolysis in Cerebral Ischemia] grade 2b), total recanalization success, hemorrhagic complications (including intracerebral hemorrhage [ICH] and subarachnoid hemorrhage), and clinical outcomes were compared between both groups. RESULTS: Two hundred and sixty patients met the inclusion criteria; 171 patients had M1 occlusion versus 89 with M2 occlusion. First passage recanalization success rate was significantly higher in the M2 group (55.1% vs. 39.2%; P = 0.015). Total recanalization success rate was higher in the M2 group but did not reach significance (83% vs. 75%; P = 0.128). Subarachnoid hemorrhage rate was significantly higher in the M2 group (25% vs. 12%; P = 0.010) but there was no difference for ICH complications (14.6% vs. 16.4%; P = 0.711). CONCLUSIONS: MT for M2 occlusions has similar overall efficacy to that for M1 occlusions, but with higher first-pass successful recanalization rates. MT for M2 occlusions has a higher risk of associated subarachnoid hemorrhage.

In Vitro Modeling of Human Brain Arteriovenous Malformation for Endovascular Simulation and Flow Analysis.

BACKGROUND: Current in vitro models for human brain arteriovenous malformation (AVM) analyzing the efficacy of embolic materials or flow conditions are limited by a lack of realistic anatomic features of complex AVM nidus. The purpose of this study was to evaluate a newly developed in vitro AVM model for embolic material testing, preclinical training, and flow analysis. METHODS: Three-dimensional (3D) images of the AVM nidus were extracted from 3D rotational angiography from a patient. Inner vascular mold was printed using a 3D printer, coated with polydimethylsiloxanes, and then was removed by acetone, leaving a hollow AVM model. Injections of liquid embolic material and 4-dimensional (4D) flow magnetic resonance imaging (MRI) were performed using the AVM models. Additionally, computational fluid dynamics analysis was performed to examine the flow volume rate as compared with 4D flow MRI. RESULTS: The manufacture of 3D in vitro AVM models delivers a realistic representation of human nidus vasculature and complexity derived from patients. The injection of liquid embolic agents performed in the in vitro model successfully replicated real-life treatment conditions. The model simulated the plug and push technique before penetration of the liquid embolic material into the AVM nidus. The 4D flow MRI results were comparable to computational fluid dynamics analysis. CONCLUSIONS: An in vitro human brain AVM model with realistic geometric complexities of nidus was successfully created using 3D printing technology. This AVM model offers a useful tool for training of embolization techniques and analysis of hemodynamics analysis, and development of new devices and materials.

A systematic review of shunt-related extraneural metastases of primary central nervous system tumors.

Extraneural metastasis (ENM) of primary central nervous system (CNS) tumors is an uncommon occurrence. Case reports and case series describe ENM after shunting, but this phenomenon has not been well characterized. In this review we aim to better understand the risk factors and clinical implications of ENM associated with shunting. A literature search of cases of ENM related to shunt placement in patients with primary CNS tumors reported through January 2018 was performed using PubMed and Google Scholar. We identified 106 cases of ENM of primary CNS tumors related to shunt placement. The three most common tumor histologies resulting in ENM were germinoma (24%), medulloblastoma (21%), and glioblastoma (11%). Of the patients with ENM, 48% had leptomeningeal spread and 37% had brain or spinal cord metastasis. Mean survival time from shunt placement was 13 months. Ventriculoatrial-shunted cases had higher rates of widespread metastasis and shorter average survival time from shunt placement (2 months) than the average of all types of shunts. Given the known association with ENM, careful consideration should be given to shunt placement in patients with primary CNS tumors, especially germinomas, medulloblastomas, and glioblastomas. Appropriate surveillance should be instituted after shunt placement, and leptomeningeal or neural metastasis should prompt the consideration of potential ENM. When considering distal shunt options, our review suggests that ventriculoatrial shunts should be avoided if possible. For truly obstructive pathologies, the risk of ENM is a further indication to consider other treatment options such as endoscopic third ventriculostomy rather than shunt placement.

Pineal germ cell tumors: Two cases with review of histopathologies and biomarkers.

Pineal germ cell tumors (GCTs) are primarily seen in pediatric and Asian populations. These tumors are divided into germinomatous and non-germinomatous GCTs (NGGCTs). GCTs are thought to arise by misplacement of totipotent stem cells en route to gonads during embryogenesis. Intracranial GCTs display an affinity to develop along the pineal-suprasellar axis and have variable manifestations dependent upon the location of the tumor. Management and outcomes are driven by histopathologies. In this study, we highlight two cases of pineal GCTs and present a review of the literature with an emphasis on histopathologies and biomarkers.

Matched Cohort Analysis of the Effects of Limb Remote Ischemic Conditioning in Patients with Aneurysmal Subarachnoid Hemorrhage.

Remote ischemic conditioning (RIC) is a powerful innate response to transient subcritical ischemia that protects against severe ischemic insults at distant sites. We have previously shown the safety and feasibility of limb RIC in aneurysmal subarachnoid hemorrhage (aSAH) patients, along with changes in neurovascular and cerebral metabolism. In this study, we aim to detect the potential effect of an established lower-limb conditioning protocol on clinical outcomes of aSAH patients. Neurologic outcome (modified Rankin Scale (mRS)) of patients enrolled in a prospective trial (RIPC-SAH) was measured. A matching algorithm was applied to identify control patients with aSAH from an institutional departmental database. RIC patients underwent four lower-limb conditioning sessions, consisting of four 5-min cycles per session over nonconsecutive days. Good functional outcome was defined as mRS of 0 to 2. The study population consisted of 21 RIC patients and 61 matched controls. There was no significant intergroup difference in age, gender, aneurysm location, clipping vs coiling, Fisher grades, Hunt and Hess grades, or vasospasm. RIC was independently associated with good outcome (OR 5.17; 95% confidence interval (CI) 1.21-25.02). RIC also showed a trend toward lower incidence of stroke (28.6 vs. 47.5%) and death (4.8 vs. 19.7%). Lower-limb RIC following aSAH appears to have a positive effect in the functional outcomes of patients with aSAH. While this effect is consistent with prior preclinical studies, future trials are necessary to conclusively evaluate the effects of RIC for aSAH.

Rigorous anaesthesia management protocol for patients with intracranial arterial stenosis: a prospective controlled-cohort study.

OBJECTIVES: Reducing variability is integral in quality management. As part of the ongoing Encephaloduroarteriosynangiosis Revascularisation for Symptomatic Intracranial Arterial Stenosis (ERSIAS) trial, we developed a strict anaesthesia protocol to minimise fluctuations in patient parameters affecting cerebral perfusion. We hypothesise that this protocol reduces the intraoperative variability of targeted monitored parameters compared to standard management. DESIGN: Prospective cohort study of patients undergoing encephaloduroarteriosynangiosis surgery versus standard neurovascular interventions. Patients with ERSIAS had strict perioperative management that included normocapnia and intentional hypertension. Control patients received regular anaesthetic standard of care. Minute-by-minute intraoperative vitals were electronically collected. Heterogeneity of variance tests were used to compare variance across groups. Mixed-model regression analysis was performed to establish the effects of treatment group on the monitored parameters. SETTING: Tertiary care centre. PARTICIPANTS: 24 participants: 12 cases (53.8 years ± 16.7 years; 10 females) and 12 controls (51.3 years ± 15.2 years; 10 females). Adults aged 30-80 years, with transient ischaemic attack or non-disabling stroke (modified Rankin Scale <3) attributed to 70-99% intracranial stenosis of the carotid or middle cerebral artery, were considered for enrolment. Controls were matched according to age, gender and history of neurovascular intervention. MAIN OUTCOME MEASURES: Variability of heart rate, mean arterial blood pressure (MAP), systolic blood pressure and end tidal CO2 (ETCO2) throughout surgical duration. RESULTS: There were significant reductions in the intraoperative MAP SD (4.26 vs 10.23 mm Hg; p=0.007) and ETCO2 SD (0.94 vs 1.26 mm Hg; p=0.05) between the ERSIAS and control groups. Median MAP and ETCO2 in the ERSIAS group were higher (98 mm Hg, IQR 23 vs 75 mm Hg, IQR 15; p<0.001, and 38 mm Hg, IQR 4 vs 32 mm Hg, IQR 3; p<0.001, respectively). CONCLUSIONS: The ERSIAS anaesthesia protocol successfully reduced intraoperative fluctuations of MAP and ETCO2. The protocol also achieved normocarbia and the intended hypertension. TRIAL REGISTRATION NUMBER: NCT01819597; Pre-results.

Management of extracranial carotid artery disease.

Stroke is the third leading cause of death in developed nations. Up to 88% of strokes are ischemic in nature. Extracranial carotid artery atherosclerotic disease is the third leading cause of ischemic stroke in the general population and the second most common nontraumatic cause among adults younger than 45 years. This article provides comprehensive, evidence-based recommendations for the management of extracranial atherosclerotic disease, including imaging for screening and diagnosis, medical management, and interventional management.

The role of regulatory T-cells in glioma immunology.

Despite recent advances in treatment, the prognosis for glioblastoma multiforme (GBM) remains poor. The lack of response to treatment in GBM patients may be attributed to the immunosuppressed microenvironment that is characteristic of invasive glioma. Regulatory T-cells (Tregs) are immunosuppressive T-cells that normally prevent autoimmunity when the human immune response is evoked; however, there have been strong correlations between glioma-induced immunosuppression and Tregs. In fact, induction of Treg activity has been correlated with glioma development in both murine models and patients. While the exact mechanisms by which regulatory T-cells function require further elucidation, various cytokines such as interleukin-10 (IL-10) and transforming growth factor-ß (TFG-ß) have been implicated in these processes and are currently under investigation. In addition, hypoxia is characteristic of tumor development and is also correlated with downstream induction of Tregs. Due to the poor prognosis associated with immunosuppression in glioma patients, Tregs remain a promising area for immunotherapeutic research.

Tight glycemic control reduces infection and improves neurological outcome in critically ill neurosurgical and neurological patients.

BACKGROUND: Tight glycemic control (TGC) may improve outcomes in hyperglycemic neurosurgical patients. The adoption of TGC has been limited by a lack of adequate data on optimal insulin delivery protocols and serum glucose concentration and by concerns about the risks of hypoglycemia. OBJECTIVE: This study was designed as a meta-analysis of outcomes to compare intensive insulin therapy and TGC with conventional insulin therapy and conventional glucose control. The secondary objective was to determine retrospectively whether a particular glucose range correlates with better outcomes. METHODS: Using electronic databases, we retrieved all English language studies published between January 1997 and December 2010 reporting outcomes in neurological and neurosurgical patients as a function of glucose levels and insulin protocols. We conducted a meta-analysis around 4 outcome measures: infection, neurological outcome, hypoglycemia, and mortality. Effect sizes in each study were individually correlated with target intensive insulin therapy glucose levels. Individual studies were assessed for quality by use of the Jadad scale. RESULTS: Nine studies reporting on 1459 patients met the inclusion criteria. Five were restricted to neurosurgical patients. Four included neurological patients. Compared with conventional glucose control, TGC lowered infection rates (odds ratio, 0.59; 95% confidence interval, 0.47-0.76; P < .001) and yielded better neurological outcomes (odds ratio, 1.72; 95% confidence interval, 1.36-2.16; P < .001). Beneficial effects increased as glucose limits tightened and study quality improved (R > 0.9 for both). TGC resulted in a higher rate of hypoglycemic events (odds ratio, 8.04; 95% confidence interval, 4.85-13.31; P < .001). Mortality was not affected. CONCLUSION: TGC reduced infection risk and improved neurological outcome despite increased rates of hypoglycemic events. An optimal target for serum glucose concentrations could not be determined.

Thalamic stimulation for epilepsy.

With the growing applications for deep brain stimulators (DBS) in recent years, interest in using DBS as an option for patients with epilepsy has increased. Thalamic DBS appears to be a viable minimally invasive treatment for patients experiencing medically intractable seizures. Thalamic DBS has been associated with significant reduction in seizure frequency and an improvement in overall quality of life, especially in patients who have failed maximal antiepileptic drugs or other surgical alternatives. However, further work is necessary to identify the subgroups of patients experiencing medically intractable seizures who may benefit from DBS, and also to indentify optimal stimulation parameters and mode of stimulation.