Publications by authors named "Chengyuan Wu"

81 Publications

Gray Matter Sampling Differences Between Subdural Electrodes and Stereoelectroencephalography Electrodes.

Front Neurol 2021 27;12:669406. Epub 2021 Apr 27.

Department of Radiology, Jefferson Integrated Magnetic Resonance Imaging Center, Thomas Jefferson University, Philadelphia, PA, United States.

Stereoelectroencephalography (SEEG) has seen a recent increase in popularity in North America; however, concerns regarding the spatial sampling capabilities of SEEG remain. We aimed to quantify and compare the spatial sampling of subdural electrode (SDE) and SEEG implants. Patients with drug-resistant epilepsy who underwent invasive monitoring were included in this retrospective case-control study. Ten SEEG cases were compared with ten matched SDE cases based on clinical presentation and pre-implantation hypothesis. To quantify gray matter sampling, MR and CT images were coregistered and a 2.5mm radius sphere was superimposed over the center of each electrode contact. The estimated recording volume of gray matter was defined as the cortical voxels within these spherical models. Paired -tests were performed to compare volumes and locations of SDE and SEEG recording. A Ripley's K-function analysis was performed to quantify differences in spatial distributions. The average recording volume of gray matter by each individual contact was similar between the two modalities. SEEG implants sampled an average of 20% more total gray matter, consisted of an average of 17% more electrode contacts, and had 77% more of their contacts covering gray matter within sulci. Insular coverage was only achieved with SEEG. SEEG implants generally consist of discrete areas of dense local coverage scattered across the brain; while SDE implants cover relatively contiguous areas with lower density recording. Average recording volumes per electrode contact are similar for SEEG and SDE, but SEEG may allow for greater overall volumes of recording as more electrodes can be routinely implanted. The primary difference lies in the location and distribution of gray matter than can be sampled. The selection between SEEG and SDE implantation depends on sampling needs of the invasive implant.
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http://dx.doi.org/10.3389/fneur.2021.669406DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8110924PMC
April 2021

Introduction: Surgical Robotics in Neurosurgery Review Series.

Oper Neurosurg (Hagerstown) 2021 05;20(6):513

Cambridge Consultants, San Francisco, California, USA.

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http://dx.doi.org/10.1093/ons/opab032DOI Listing
May 2021

Proceedings of the Eighth Annual Deep Brain Stimulation Think Tank: Advances in Optogenetics, Ethical Issues Affecting DBS Research, Neuromodulatory Approaches for Depression, Adaptive Neurostimulation, and Emerging DBS Technologies.

Front Hum Neurosci 2021 19;15:644593. Epub 2021 Apr 19.

Neurologischen Klinik Universitätsklinikum Würzburg, Würzburg, Germany.

We estimate that 208,000 deep brain stimulation (DBS) devices have been implanted to address neurological and neuropsychiatric disorders worldwide. DBS Think Tank presenters pooled data and determined that DBS expanded in its scope and has been applied to multiple brain disorders in an effort to modulate neural circuitry. The DBS Think Tank was founded in 2012 providing a space where clinicians, engineers, researchers from industry and academia discuss current and emerging DBS technologies and logistical and ethical issues facing the field. The emphasis is on cutting edge research and collaboration aimed to advance the DBS field. The Eighth Annual DBS Think Tank was held virtually on September 1 and 2, 2020 (Zoom Video Communications) due to restrictions related to the COVID-19 pandemic. The meeting focused on advances in: (1) optogenetics as a tool for comprehending neurobiology of diseases and on optogenetically-inspired DBS, (2) cutting edge of emerging DBS technologies, (3) ethical issues affecting DBS research and access to care, (4) neuromodulatory approaches for depression, (5) advancing novel hardware, software and imaging methodologies, (6) use of neurophysiological signals in adaptive neurostimulation, and (7) use of more advanced technologies to improve DBS clinical outcomes. There were 178 attendees who participated in a DBS Think Tank survey, which revealed the expansion of DBS into several indications such as obesity, post-traumatic stress disorder, addiction and Alzheimer's disease. This proceedings summarizes the advances discussed at the Eighth Annual DBS Think Tank.
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http://dx.doi.org/10.3389/fnhum.2021.644593DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8092047PMC
April 2021

Capturing Initial Understanding and Impressions of Surgical Therapy for Parkinson's Disease.

Front Neurol 2021 4;12:605959. Epub 2021 Mar 4.

Department of Neurosurgery, Thomas Jefferson University, Philadelphia, PA, United States.

Deep Brain Stimulation (DBS) is an underutilized surgical therapy for Parkinson's Disease (PD). Both physician and patient hesitancies have been described as potential barriers to DBS, but the specifics of patient perceptions of DBS have not been well-characterized in the general PD population. To characterize the understanding and impressions of surgical therapy in PD patients prior to formal surgical evaluation. A 30-question survey assessing impressions of surgical therapy for PD and understanding of DBS for PD was administered to PD patients seen at an urban movement disorders clinic. One hundred and two patients completed the survey. When asked if they would undergo a hypothetical risk-free, curative brain surgery for PD, 98 patients responded "yes." Patients were more agreeable to "reversible," "minimally-invasive," and "incisionless" surgery. 51.2% thought DBS is an "effective" treatment for PD, 76.6% thought it was "invasive," and 18.3% thought it was "reversible." 45.2% reported fear of being awake during DBS surgery. Regarding costs, 52.4% were concerned that DBS was "very expensive" or "not covered by insurance." Initial source of information and perceived treatment effectiveness were not associated with concerns about DBS effectiveness or threats to normality. Negative perceptions of past surgery were associated with concerns about DBS altering mood and personality. Overall, patients expressed concerns regarding procedural efficacy, invasiveness, cost, and irreversibility-independent of the original source of information. Future studies are required to allow us to better understand the impact of these initial findings on DBS hesitancy and underutilization.
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http://dx.doi.org/10.3389/fneur.2021.605959DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7970030PMC
March 2021

Are Guidelines Important? Results of a Prospective Quality Improvement Lumbar Fusion Project.

Neurosurgery 2021 Jun;89(1):77-84

Department of Neurological Surgery, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania, USA.

Background: United States (U.S.) healthcare is a volume-based inefficient delivery system. Value requires the consideration of quality, which is lacking in most healthcare disciplines.

Objective: To assess whether patients who met specific evidence-based medicine (EBM)-based criteria preoperatively for lumbar fusion would achieve higher rates of achieving the minimal clinical important difference (MCID) than those who did not meet the EBM indications.

Methods: All elective lumbar fusion cases, March 2018 to August 2019, were prospectively evaluated and categorized based on EBM guidelines for surgical indications. The MCID was defined as a reduction of ≥5 points in Oswestry Disability Index (ODI). Multiple logistic regression identified multivariable-adjusted odds ratio of EBM concordance.

Results: A total of 325 lumbar fusion patients were entered with 6-mo follow-up data available for 309 patients (95%). The median preoperative ODI score was 24.4 with median 6-mo improvement of 7.0 points (P < .0001). Based on ODI scores, 79.6% (246/309) improved, 3.8% (12/309) had no change, and 16% (51/309) worsened. A total of 191 patients had ODI improvement reaching the MCID. 93.2% (288/309) cases were EBM concordant, while 6.7% (21/309) were not.In multivariate analysis, EBM concordance (P = .0338), lower preoperative ODI (P < .001), lower ASA (American Society of Anesthesiologists) (P = .0056), and primary surgeries (P = .0004) were significantly associated with improved functional outcome. EBM concordance conferred a 3.04 (95% CI 1.10-8.40) times greater odds of achieving MCID in ODI at 6 mo (P = .0322), adjusting for other factors.

Conclusion: This analysis provides validation of EBM guideline criteria to establish optimal patient outcomes. The EBM concordant patients had a greater than 3 times improved outcome compared to those not meeting EBM fusion criteria.
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http://dx.doi.org/10.1093/neuros/nyab062DOI Listing
June 2021

High-Frequency Spinal Cord Stimulation at 10 kHz for the Treatment of Nonsurgical Refractory Back Pain: Design of a Pragmatic, Multicenter, Randomized Controlled Trial.

Pain Pract 2021 Feb 26;21(2):171-183. Epub 2020 Sep 26.

Nevro Corp, Redwood City, California, U.S.A.

Background: Spinal cord stimulation (SCS) has been shown to provide pain relief for chronic back and leg pain due to failed back surgery syndrome. But many patients with chronic back pain have not had major back surgery or are not good candidates for surgery, and conventional medical management (CMM) provides limited relief. We have termed this condition nonsurgical refractory back pain (NSRBP). Level 1 evidence does not yet exist showing the therapeutic benefit of SCS for NSRBP.

Objective: To compare 10-kHz SCS plus CMM (10-kHz SCS + CMM) to CMM alone for treatment of NSRBP in terms of clinical and cost effectiveness.

Study Design: Multicenter, randomized controlled trial (RCT), with subjects randomized 1:1 to either 10-kHz SCS + CMM or CMM alone. Optional crossover occurs at 6 months if treatment does not achieve ≥50% pain relief.

Methods: Patients with NSRBP as defined above may be enrolled if they are ineligible for surgery based on surgical consultation. Subjects randomized to 10-kHz SCS + CMM will receive a permanent implant if sufficient pain relief is achieved in a temporary trial. Both groups will receive CMM per standard of care and will undergo assessments at baseline and at follow-ups to 12 months. Self-report outcomes include pain, disability, sleep, mental health, satisfaction, healthcare utilization, and quality of life.

Results: Enrollment was initiated on September 10, 2018. Prespecified independent interim analysis at 40% of the enrollment target indicated the sample size was sufficient to show superiority of treatment at the primary endpoint; therefore, enrollment was stopped at 211.

Conclusions: This large multicenter RCT will provide valuable evidence to guide clinical decisions in NSRBP.
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http://dx.doi.org/10.1111/papr.12945DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7891432PMC
February 2021

Consequences of mesial temporal sparing temporal lobe surgery in medically refractory epilepsy.

Epilepsy Behav 2021 02 23;115:107642. Epub 2020 Dec 23.

Jefferson Comprehensive Epilepsy Center, Thomas Jefferson University, Philadelphia, PA, United States; Department of Neurology, Thomas Jefferson University, Philadelphia, PA, United States.

Objective: We compared long-term seizure outcome, neuropsychological outcome, and occupational outcome of anterior temporal lobectomy (ATL) with and without sparing of mesial structures to determine whether mesial sparing temporal lobectomy prevents memory decline and thus disability, with acceptable seizure outcome.

Methods: We studied patients (n = 21) and controls (n = 21) with no evidence of mesial temporal sclerosis (MTS) on MRI who had surgery to treat drug-resistant epilepsy. Demographic and pre- and postsurgical clinical characteristics were compared. Patients had neuropsychological assessment before and after surgery. Neuropsychological analyses were limited to patients with left-sided surgery and available data (n = 14 in each group) as they were at risk of verbal memory impairment. The California Verbal Learning Test II (CVLT-II) (sum of trials 1-5, delayed free recall) and the Logical Memory subtest of the Wechsler Memory Scale III or IV (WMS-III or WMS-IV) (learning and delayed recall of prose passages) were used to assess verbal episodic learning and memory. Seizure and occupational outcomes were assessed.

Results: The chance of attaining seizure freedom was similar in the two groups, so sparing mesial temporal structures did not lessen the chance of stopping seizures. Sparing mesial temporal structures mitigated the extent of postoperative verbal memory impairment, though some of these individuals suffered decline as a consequence of surgery. Occupational outcome was similar in both groups.

Significance: Mesial temporal sparing resections provide a similar seizure outcome as ATL, while producing a better memory outcome. Anterior temporal lobectomy including mesial structure resection did not increase the risk of postoperative disability.
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http://dx.doi.org/10.1016/j.yebeh.2020.107642DOI Listing
February 2021

The Impact of Responsive Neurostimulation on the Treatment of Epilepsy.

Neurol India 2020 Nov-Dec;68(Supplement):S278-S281

Professor, Department of Neurological Surgery, Thomas Jefferson University Hospitals, Philadelphia, PA, USA.

There is a considerable number of patients with epilepsy that have drug resistant epilepsy (DRE). An additional option for these patients is resective surgery of ictal onset zones. However, a significant portion of DRE patients have unidentified or unresectable ictal zones. For these patients, RNS is a potential treatment option. The RNS system is a closed loop system that delivers stimulation in response to ECoG changes at seizure foci. It is programmed with an algorithm capable of detecting specific patterns of epileptogenic activity and triggers focal stimulation to interrupt seizures. The long term monitoring potential of the RNS system allows for a better understanding of the circadian rhythms behind epilepsy.
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http://dx.doi.org/10.4103/0028-3886.302468DOI Listing
June 2021

Robot-Assisted Stereotaxy Reduces Target Error: A Meta-Analysis and Meta-Regression of 6056 Trajectories.

Neurosurgery 2021 01;88(2):222-233

Department of Neurological Surgery, Thomas Jefferson University Hospitals, Philadelphia, Pennsylvania.

Background: The pursuit of improved accuracy for localization and electrode implantation in deep brain stimulation (DBS) and stereoelectroencephalography (sEEG) has fostered an abundance of disparate surgical/stereotactic practices. Specific practices/technologies directly modify implantation accuracy; however, no study has described their respective influence in multivariable context.

Objective: To synthesize the known literature to statistically quantify factors affecting implantation accuracy.

Methods: A systematic review and meta-analysis was conducted to determine the inverse-variance weighted pooled mean target error (MTE) of implanted electrodes among patients undergoing DBS or sEEG. MTE was defined as Euclidean distance between planned and final electrode tip. Meta-regression identified moderators of MTE in a multivariable-adjusted model.

Results: A total of 37 eligible studies were identified from a search return of 2,901 potential articles (2002-2018) - 27 DBS and 10 sEEG. Random-effects pooled MTE = 1.91 mm (95% CI: 1.7-2.1) for DBS and 2.34 mm (95% CI: 2.1-2.6) for sEEG. Meta-regression identified study year, robot use, frame/frameless technique, and intraoperative electrophysiologic testing (iEPT) as significant multivariable-adjusted moderators of MTE (P < .0001, R2 = 0.63). Study year was associated with a 0.92-mm MTE reduction over the 16-yr study period (P = .0035), and robot use with a 0.79-mm decrease (P = .0019). Frameless technique was associated with a mean 0.50-mm (95% CI: 0.17-0.84) increase, and iEPT use with a 0.45-mm (95% CI: 0.10-0.80) increase in MTE. Registration method, imaging type, intraoperative imaging, target, and demographics were not significantly associated with MTE on multivariable analysis.

Conclusion: Robot assistance for stereotactic electrode implantation is independently associated with improved accuracy and reduced target error. This remains true regardless of other procedural factors, including frame-based vs frameless technique.
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http://dx.doi.org/10.1093/neuros/nyaa428DOI Listing
January 2021

Functionally distinct high and low theta oscillations in the human hippocampus.

Nat Commun 2020 05 18;11(1):2469. Epub 2020 May 18.

Department of Biomedical Engineering, Columbia University, New York, NY, 10027, USA.

Based on rodent models, researchers have theorized that the hippocampus supports episodic memory and navigation via the theta oscillation, a ~4-10 Hz rhythm that coordinates brain-wide neural activity. However, recordings from humans have indicated that hippocampal theta oscillations are lower in frequency and less prevalent than in rodents, suggesting interspecies differences in theta's function. To characterize human hippocampal theta, we examine the properties of theta oscillations throughout the anterior-posterior length of the hippocampus as neurosurgical subjects performed a virtual spatial navigation task. During virtual movement, we observe hippocampal oscillations at multiple frequencies from 2 to 14 Hz. The posterior hippocampus prominently displays oscillations at ~8-Hz and the precise frequency of these oscillations correlates with the speed of movement, implicating these signals in spatial navigation. We also observe slower ~3 Hz oscillations, but these signals are more prevalent in the anterior hippocampus and their frequency does not vary with movement speed. Our results converge with recent findings to suggest an updated view of human hippocampal electrophysiology. Rather than one hippocampal theta oscillation with a single general role, high- and low-frequency theta oscillations, respectively, may reflect spatial and non-spatial cognitive processes.
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http://dx.doi.org/10.1038/s41467-020-15670-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7235253PMC
May 2020

Ripples Have Distinct Spectral Properties and Phase-Amplitude Coupling With Slow Waves, but Indistinct Unit Firing, in Human Epileptogenic Hippocampus.

Front Neurol 2020 24;11:174. Epub 2020 Mar 24.

Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States.

Ripple oscillations (80-200 Hz) in the normal hippocampus are involved in memory consolidation during rest and sleep. In the epileptic brain, increased ripple and fast ripple (200-600 Hz) rates serve as a biomarker of epileptogenic brain. We report that both ripples and fast ripples exhibit a preferred phase angle of coupling with the trough-peak (or On-Off) state transition of the sleep slow wave in the hippocampal seizure onset zone (SOZ). Ripples on slow waves in the hippocampal SOZ also had a lower power, greater spectral frequency, and shorter duration than those in the non-SOZ. Slow waves in the mesial temporal lobe modulated the baseline firing rate of excitatory neurons, but did not significantly influence the increased firing rate associated with ripples. In summary, pathological ripples and fast ripples occur preferentially during the On-Off state transition of the slow wave in the epileptogenic hippocampus, and ripples do not require the increased recruitment of excitatory neurons.
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http://dx.doi.org/10.3389/fneur.2020.00174DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7118726PMC
March 2020

Computer-assisted planning for minimally invasive anterior two-thirds laser corpus callosotomy: A feasibility study with probabilistic tractography validation.

Neuroimage Clin 2020 13;25:102174. Epub 2020 Jan 13.

Department of Clinical and Experimental Epilepsy, University College London, London, UK; Chalfont Centre for Epilepsy and National Hospital for Neurology and Neurosurgery, Queen Square, London, UK.

Background: Anterior two-thirds corpus callosotomy is an effective palliative neurosurgical procedure for drug-refractory epilepsy that is most commonly used to treat drop-attacks. Laser interstitial thermal therapy is a novel stereotactic ablative technique that has been utilised as a minimally invasive alternative to resective and disconnective open neurosurgery. Case series have reported success in performing laser anterior two-thirds corpus callosotomy. Computer-assisted planning algorithms may help to automate and optimise multi-trajectory planning for this procedure.

Objective: To undertake a simulation-based feasibility study of computer-assisted corpus callostomy planning in comparison with expert manual plans in the same patients.

Methods: Ten patients were selected from a prospectively maintained database. Patients had previously undergone diffusion-weighted imaging and digital subtraction angiography as part of routine SEEG care. Computer-assisted planning was performed using the EpiNav™ platform and compared to manually planned trajectories from two independent blinded experts. Estimated ablation cavities were used in conjunction with probabilistic tractography to simulate the expected extent of interhemispheric disconnection.

Results: Computer-assisted planning resulted in significantly improved trajectory safety metrics (risk score and minimum distance to vasculature) compared to blinded external expert manual plans. Probabilistic tractography revealed residual interhemispheric connectivity in 1/10 cases following computer-assisted planning compared to 4/10 and 2/10 cases with manual planning.

Conclusion: Computer-assisted planning successfully generates multi-trajectory plans capable of LITT anterior two-thirds corpus callosotomy. Computer-assisted planning may provide a means of standardising trajectory planning and serves as a potential new tool for optimising trajectories. A prospective validation study is now required to determine if this translates into improved patient outcomes.
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http://dx.doi.org/10.1016/j.nicl.2020.102174DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6994706PMC
January 2021

Clinically Significant Visual Deficits after Laser Interstitial Thermal Therapy for Mesiotemporal Epilepsy.

Stereotact Funct Neurosurg 2019 14;97(5-6):347-355. Epub 2020 Jan 14.

Department of Neurological Surgery, University of Miami, Miami, Florida, USA,

Background: Laser interstitial thermal therapy (LITT) has recently gained popularity as a minimally invasive surgical option for the treatment of mesiotemporal epilepsy (mTLE). Similar to traditional open procedures for epilepsy, the most frequent neurological complications of LITT are visual deficits; however, a critical analysis of these injuries is lacking.

Objectives: To evaluate the visual deficits that occur after LITT for mTLE and their etiology.

Method: We surveyed five academic epilepsy centers that regularly perform LITT for cases of self-reported postoperative visual deficits. For these patients all pre-, intra- and postoperative MRIs were co-registered with an anatomic atlas derived from 7T MRI data. This was used to estimate thermal injury to early visual pathways and measure imaging variables relevant to the LITT procedure. Using logistic regression, we then compared 14 variables derived from demographics, mesiotemporal anatomy, and the surgical procedure for the patients with visual deficits to a normal cohort comprised of the first 30 patients to undergo this procedure at a single institution.

Results: Of 90 patients that underwent LITT for mTLE, 6 (6.7%) reported a postoperative visual deficit. These included 2 homonymous hemianopsias (HHs), 2 quadrantanopsias, and 2 cranial nerve (CN) IV palsies. These deficits localized to the posterior aspect of the ablation, corresponding to the hippocampal body and tail, and tended to have greater laser energy delivered in that region than the normal cohort. The patients with HH had insult localized to the lateral geniculate nucleus, which was -associated with young age and low choroidal fissure CSF volume. Quadrantanopsia, likely from injury to the optic radiation in Meyer's loop, was correlated with a lateral trajectory and excessive energy delivered at the tail end of the ablation. Patients with CN IV injury had extension of contrast to the tentorial edge associated with a mesial laser trajectory.

Conclusions: LITT for epilepsy may be complicated by various classes of visual deficit, each with distinct etiology and clinical significance. It is our hope that by better understanding these injuries and their mechanisms we can eventually reduce their occurrence by identifying at-risk patients and trajectories and appropriately tailoring the ablation procedure.
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http://dx.doi.org/10.1159/000504856DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7998682PMC
June 2020

Memory retrieval modulates spatial tuning of single neurons in the human entorhinal cortex.

Nat Neurosci 2019 12 11;22(12):2078-2086. Epub 2019 Nov 11.

Department of Biomedical Engineering, Columbia University, New York, NY, USA.

The medial temporal lobe is critical for both spatial navigation and memory. Although single neurons in the medial temporal lobe activate to represent locations in the environment during navigation, how this spatial tuning relates to memory for events involving those locations remains unclear. We examined memory-related changes in spatial tuning by recording single-neuron activity from neurosurgical patients performing a virtual-reality object-location memory task. We identified 'memory-trace cells' with activity that was spatially tuned to the retrieved location of the specific object that participants were cued to remember. Memory-trace cells in the entorhinal cortex, in particular, encoded discriminable representations of different memories through a memory-specific rate code. These findings indicate that single neurons in the human entorhinal cortex change their spatial tuning to target relevant memories for retrieval.
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http://dx.doi.org/10.1038/s41593-019-0523-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6897360PMC
December 2019

Commentary: Using Directional Deep Brain Stimulation to Co-activate the Subthalamic Nucleus and Zona Incerta for Overlapping Essential Tremor/Parkinson's Disease Symptoms.

Front Neurol 2019 6;10:854. Epub 2019 Sep 6.

Division of Epilepsy and Neuromodulation Neurosurgery, Department of Neurosurgery, Vickie and Jack Farber Institute for Neuroscience, Thomas Jefferson University, Philadelphia, PA, United States.

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http://dx.doi.org/10.3389/fneur.2019.00854DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6742774PMC
September 2019

Magnus representation of genome sequences.

J Theor Biol 2019 11 6;480:104-111. Epub 2019 Aug 6.

Division of Mathematical Sciences, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore; School of Biological Sciences, Nanyang Technological University, Singapore 637371, Singapore. Electronic address:

We introduce an alignment-free method, the Magnus Representation, to analyze genome sequences. The Magnus Representation captures higher-order information in genome sequences. We combine our approach with the idea of k-mers to define an effectively computable Mean Magnus Vector. We perform phylogenetic analysis on three datasets: mosquito-borne viruses, filoviruses, and bacterial genomes. Our results on ebolaviruses are consistent with previous phylogenetic analyses, and confirm the modern viewpoint that the 2014 West African Ebola outbreak likely originated from Central Africa. Our analysis also confirms the close relationship between Bundibugyo ebolavirus and Taï Forest ebolavirus. For bacterial genomes, our method is able to classify relatively well at the family and genus level, as well as at higher levels such as phylum level. The bacterial genomes are also separated well into Gram-positive and Gram-negative subgroups.
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http://dx.doi.org/10.1016/j.jtbi.2019.08.004DOI Listing
November 2019

Multicenter validation of automated trajectories for selective laser amygdalohippocampectomy.

Epilepsia 2019 09 7;60(9):1949-1959. Epub 2019 Aug 7.

Department of Clinical and Experimental Epilepsy, Queen Square Institute of Neurology, University College London, London, UK.

Objective: Laser interstitial thermal therapy (LITT) is a novel minimally invasive alternative to open mesial temporal resection in drug-resistant mesial temporal lobe epilepsy (MTLE). The safety and efficacy of the procedure are dependent on the preplanned trajectory and the extent of the planned ablation achieved. Ablation of the mesial hippocampal head has been suggested to be an independent predictor of seizure freedom, whereas sparing of collateral structures is thought to result in improved neuropsychological outcomes. We aim to validate an automated trajectory planning platform against manually planned trajectories to objectively standardize the process.

Methods: Using the EpiNav platform, we compare automated trajectory planning parameters derived from expert opinion and machine learning to undertake a multicenter validation against manually planned and implemented trajectories in 95 patients with MTLE. We estimate ablation volumes of regions of interest and quantify the size of the avascular corridor through the use of a risk score as a marker of safety. We also undertake blinded external expert feasibility and preference ratings.

Results: Automated trajectory planning employs complex algorithms to maximize ablation of the mesial hippocampal head and amygdala, while sparing the parahippocampal gyrus. Automated trajectories resulted in significantly lower calculated risk scores and greater amygdala ablation percentage, whereas overall hippocampal ablation percentage did not differ significantly. In addition, estimated damage to collateral structures was reduced. Blinded external expert raters were significantly more likely to prefer automated to manually planned trajectories.

Significance: Retrospective studies of automated trajectory planning show much promise in improving safety parameters and ablation volumes during LITT for MTLE. Multicenter validation provides evidence that the algorithm is robust, and blinded external expert ratings indicate that the trajectories are clinically feasible. Prospective validation studies are now required to determine if automated trajectories translate into improved seizure freedom rates and reduced neuropsychological deficits.
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http://dx.doi.org/10.1111/epi.16307DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6771574PMC
September 2019

Waves of Pain Relief: A Systematic Review of Clinical Trials in Spinal Cord Stimulation Waveforms for the Treatment of Chronic Neuropathic Low Back and Leg Pain.

World Neurosurg 2019 Nov 30;131:264-274.e3. Epub 2019 Jul 30.

Department of Neurosurgery, Vicki and Jack Farber Institute for Neuroscience, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.

In the United States, chronic low back pain affects up to 37% of adults and is a multibillion dollar health care expenditure. Spinal cord simulation (SCS) has been established as an effective treatment alternative for chronic neuropathic low back and leg pain, especially for patients with failed back surgery syndrome or chronic regional pain syndrome. The field of SCS has rapidly advanced such that analgesia can now be achieved through numerous different waveforms, each claiming to offer improved outcomes. These waveforms include traditional paresthesia-based SCS (<100 Hz), paresthesia-free high-frequency SCS (5-10 kHz), burst SCS, and subperception SCS (1-5 kHz). Level 1 evidence critically evaluating the efficacy of these different waveforms is lacking. We conducted a systematic review of the literature in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to identify all randomized controlled trials of SCS in the treatment of chronic neuropathic low back and leg pain, failed back surgery syndrome, or chronic regional pain syndrome. Of 38 eligible studies reviewed, 13 randomized controlled trials were finally included in our systematic review. We reviewed evidence from randomized controlled trials in the field of SCS that have established paresthesia-based SCS, paresthesia-free high-frequency SCS, burst SCS, and subperception SCS as viable treatment options for chronic neuropathic low back and leg pain. We critically evaluated evidence that claims to support the use of one waveform over another and reviewed the literature on patient preference for different waveforms.
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http://dx.doi.org/10.1016/j.wneu.2019.07.167DOI Listing
November 2019

Implantable Pulse Generator Site May Be Associated With Spinal Cord Stimulation Revision Surgeries.

Neuromodulation 2019 Jun 19. Epub 2019 Jun 19.

Department of Neurological Surgery, Thomas Jefferson University Hospital, Philadelphia, PA, USA.

Background: The use of implantable pulse generators (IPG) for spinal cord stimulation (SCS) in patients with chronic pain has been well established. Although IPG-related complications have been reported on, the association between IPG site and SCS complications has not been well studied.

Objective: To investigate whether IPG placement site in buttock or flank is associated with SCS complications and, hence, revision surgeries.

Method: A retrospective cohort study was performed that included 330 patients (52% female) treated at a single institution who underwent permanent implantation of an SCS system between 2014 and 2018. Patients ranged between 20 and 94 years of age (mean: 57.54 ± 13.25). Statistical analyses were conducted using IBM SPSS Statistics. Tests included independent samples t test, chi-square test, Mann-Whitney U test, Spearman's rank correlation coefficient, and logistic regression.

Results: There was a total of 93 revision surgeries (rate of 28%), where 71 out of 330 patients (rate of 21.5%) had had at least one revision surgery. Univariate tests demonstrated a significant association between IPG site and revision surgeries (p = 0.028 [chi-square test] and p = 0.031 [Mann-Whitney U test]); however, multivariate logistic regression demonstrated that neither IPG site was more likely than the other to require revision surgeries (p = 0.286).

Conclusion: Although this study found a significant association between IPG site and revision surgeries, the effect of IPG site was not found to be predictive. The IPG site likely influences whether a patient will require revision surgery, but further investigation is required to establish this association.
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http://dx.doi.org/10.1111/ner.12976DOI Listing
June 2019

Automated fiber tract reconstruction for surgery planning: Extensive validation in language-related white matter tracts.

Neuroimage Clin 2019 28;23:101883. Epub 2019 May 28.

School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK.

Diffusion MRI and tractography hold great potential for surgery planning, especially to preserve eloquent white matter during resections. However, fiber tract reconstruction requires an expert with detailed understanding of neuroanatomy. Several automated approaches have been proposed, using different strategies to reconstruct the white matter tracts in a supervised fashion. However, validation is often limited to comparison with manual delineation by overlap-based measures, which is limited in characterizing morphological and topological differences. In this work, we set up a fully automated pipeline based on anatomical criteria that does not require manual intervention, taking advantage of atlas-based criteria and advanced acquisition protocols available on clinical-grade MRI scanners. Then, we extensively validated it on epilepsy patients with specific focus on language-related bundles. The validation procedure encompasses different approaches, including simple overlap with manual segmentations from two experts, feasibility ratings from external multiple clinical raters and relation with task-based functional MRI. Overall, our results demonstrate good quantitative agreement between automated and manual segmentation, in most cases better performances of the proposed method in qualitative terms, and meaningful relationships with task-based fMRI. In addition, we observed significant differences between experts in terms of both manual segmentation and external ratings. These results offer important insights on how different levels of validation complement each other, supporting the idea that overlap-based measures, although quantitative, do not offer a full perspective on the similarities and differences between automated and manual methods.
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http://dx.doi.org/10.1016/j.nicl.2019.101883DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6545442PMC
June 2020

Effects of surgical targeting in laser interstitial thermal therapy for mesial temporal lobe epilepsy: A multicenter study of 234 patients.

Epilepsia 2019 06 21;60(6):1171-1183. Epub 2019 May 21.

Department of Neurological Surgery, Henry Ford Health System, Detroit, Michigan.

Objective: Laser interstitial thermal therapy (LITT) for mesial temporal lobe epilepsy (mTLE) has reported seizure freedom rates between 36% and 78% with at least 1 year of follow-up. Unfortunately, the lack of robust methods capable of incorporating the inherent variability of patient anatomy, the variability of the ablated volumes, and clinical outcomes have limited three-dimensional quantitative analysis of surgical targeting and its impact on seizure outcomes. We therefore aimed to leverage a novel image-based methodology for normalizing surgical therapies across a large multicenter cohort to quantify the effects of surgical targeting on seizure outcomes in LITT for mTLE.

Methods: This multicenter, retrospective cohort study included 234 patients from 11 centers who underwent LITT for mTLE. To investigate therapy location, all ablation cavities were manually traced on postoperative magnetic resonance imaging (MRI), which were subsequently nonlinearly normalized to a common atlas space. The association of clinical variables and ablation location to seizure outcome was calculated using multivariate regression and Bayesian models, respectively.

Results: Ablations including more anterior, medial, and inferior temporal lobe structures, which involved greater amygdalar volume, were more likely to be associated with Engel class I outcomes. At both 1 and 2 years after LITT, 58.0% achieved Engel I outcomes. A history of bilateral tonic-clonic seizures decreased chances of Engel I outcome. Radiographic hippocampal sclerosis was not associated with seizure outcome.

Significance: LITT is a viable treatment for mTLE in patients who have been properly evaluated at a comprehensive epilepsy center. Consideration of surgical factors is imperative to the complete assessment of LITT. Based on our model, ablations must prioritize the amygdala and also include the hippocampal head, parahippocampal gyrus, and rhinal cortices to maximize chances of seizure freedom. Extending the ablation posteriorly has diminishing returns. Further work is necessary to refine this analysis and define the minimal zone of ablation necessary for seizure control.
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http://dx.doi.org/10.1111/epi.15565DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6551254PMC
June 2019

Neuromodulation: Successful Treatments, Future Opportunity, and Challenges.

Neurosurg Clin N Am 2019 Apr 18;30(2):xiii. Epub 2019 Feb 18.

Department of Neurological Surgery, Thomas Jefferson University Hospitals, 909 Walnut Street, Third Floor, Philadelphia, PA 19107, USA. Electronic address:

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http://dx.doi.org/10.1016/j.nec.2019.01.003DOI Listing
April 2019

Responsive Neurostimulation for the Treatment of Epilepsy.

Neurosurg Clin N Am 2019 Apr 18;30(2):231-242. Epub 2019 Feb 18.

Department of Neurological Surgery, Thomas Jefferson University Hospitals, Philadelphia, PA, USA.

There are a significant number of patients with epilepsy who are drug-resistant and for whom resective procedures are not an option. For these patients, neuromodulation may be an option, including closed-loop stimulation, such as responsive neurostimulation (RNS). The RNS System is a programmable and responsive device that consists of leads, a pulse generator, and an external programmer. An algorithm detects specific patterns of epileptogenic activity and triggers focal stimulation to interrupt a seizure. RNS is an effective and safe adjunctive therapy that in addition to seizure frequency reduction may have other applications, such as drug-response evaluation and long-term electrocorticography recording.
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http://dx.doi.org/10.1016/j.nec.2018.12.006DOI Listing
April 2019

Association of Piriform Cortex Resection With Surgical Outcomes in Patients With Temporal Lobe Epilepsy.

JAMA Neurol 2019 06;76(6):690-700

UK National Institute for Health Research, University College London (UCL) Hospitals Biomedical Research Centre, Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom.

Importance: A functional area associated with the piriform cortex, termed area tempestas, has been implicated in animal studies as having a crucial role in modulating seizures, but similar evidence is limited in humans.

Objective: To assess whether removal of the piriform cortex is associated with postoperative seizure freedom in patients with temporal lobe epilepsy (TLE) as a proof-of-concept for the relevance of this area in human TLE.

Design, Setting, And Participants: This cohort study used voxel-based morphometry and volumetry to assess differences in structural magnetic resonance imaging (MRI) scans in consecutive patients with TLE who underwent epilepsy surgery in a single center from January 1, 2005, through December 31, 2013. Participants underwent presurgical and postsurgical structural MRI and had at least 2 years of postoperative follow-up (median, 5 years; range, 2-11 years). Patients with MRI of insufficient quality were excluded. Findings were validated in 2 independent cohorts from tertiary epilepsy surgery centers. Study follow-up was completed on September 23, 2016, and data were analyzed from September 24, 2016, through April 24, 2018.

Exposures: Standard anterior temporal lobe resection.

Main Outcomes And Measures: Long-term postoperative seizure freedom.

Results: In total, 107 patients with unilateral TLE (left-sided in 68; 63.6% women; median age, 37 years [interquartile range {IQR}, 30-45 years]) were included in the derivation cohort. Reduced postsurgical gray matter volumes were found in the ipsilateral piriform cortex in the postoperative seizure-free group (n = 46) compared with the non-seizure-free group (n = 61). A larger proportion of the piriform cortex was resected in the seizure-free compared with the non-seizure-free groups (median, 83% [IQR, 64%-91%] vs 52% [IQR, 32%-70%]; P < .001). The results were seen in left- and right-sided TLE and after adjusting for clinical variables, presurgical gray matter alterations, presurgical hippocampal volumes, and the proportion of white matter tract disconnection. Findings were externally validated in 2 independent cohorts (31 patients; left-sided TLE in 14; 54.8% women; median age, 41 years [IQR, 31-46 years]). The resected proportion of the piriform cortex was individually associated with seizure outcome after surgery (derivation cohort area under the curve, 0.80 [P < .001]; external validation cohorts area under the curve, 0.89 [P < .001]). Removal of at least half of the piriform cortex increased the odds of becoming seizure free by a factor of 16 (95% CI, 5-47; P < .001). Other mesiotemporal structures (ie, hippocampus, amygdala, and entorhinal cortex) and the overall resection volume were not associated with outcomes.

Conclusions And Relevance: These results support the importance of resecting the piriform cortex in neurosurgical treatment of TLE and suggest that this area has a key role in seizure generation.
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http://dx.doi.org/10.1001/jamaneurol.2019.0204DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6490233PMC
June 2019

The Insula and Its Epilepsies.

Epilepsy Curr 2019 Jan 31;19(1):11-21. Epub 2019 Jan 31.

8 Northwell Health, Great Neck, NY, USA.

Insular seizures are great mimickers of seizures originating elsewhere in the brain. The insula is a highly connected brain structure. Seizures may only become clinically evident after ictal activity propagates out of the insula with semiology that reflects the propagation pattern. Insular seizures with perisylvian spread, for example, manifest first as throat constriction, followed next by perioral and hemisensory symptoms, and then by unilateral motor symptoms. On the other hand, insular seizures may spread instead to the temporal and frontal lobes and present like seizures originating from these regions. Due to the location of the insula deep in the brain, interictal and ictal scalp electroencephalogram (EEG) changes can be variable and misleading. Magnetic resonance imaging, magnetic resonance spectroscopy, magnetoencephalography, positron emission tomography, and single-photon computed tomography imaging may assist in establishing a diagnosis of insular epilepsy. Intracranial EEG recordings from within the insula, using stereo-EEG or depth electrode techniques, can prove insular seizure origin. Seizure onset, most commonly seen as low-voltage, fast gamma activity, however, can be highly localized and easily missed if the insula is only sparsely sampled. Moreover, seizure spread to the contralateral insula and other brain regions may occur rapidly. Extensive sampling of the insula with multiple electrode trajectories is necessary to avoid these pitfalls. Understanding the functional organization of the insula is helpful when interpreting the semiology produced by insular seizures. Electrical stimulation mapping around the central sulcus of the insula results in paresthesias, while stimulation of the posterior insula typically produces painful sensations. Visceral sensations are the next most common result of insular stimulation. Treatment of insular epilepsy is evolving, but poses challenges. Surgical resections of the insula are effective but risk significant morbidity if not carefully planned. Neurostimulation is an emerging option for treatment, especially for seizures with onset in the posterior insula. The close association of the insula with marked autonomic changes has led to interest in the role of the insula in sudden unexpected death in epilepsy and warrants additional study with larger patient cohorts.
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http://dx.doi.org/10.1177/1535759718822847DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6610377PMC
January 2019

Laser interstitial thermal therapy in drug-resistant epilepsy.

Curr Opin Neurol 2019 04;32(2):237-245

Department of Neurology, Jefferson Comprehensive Epilepsy Center.

Purpose Of Review: MRI-guided stereotactic laser interstitial thermal therapy (LiTT) has been utilized in the surgical treatment of discrete, small epileptogenic lesions. This review summarizes the current literature and addresses the clinical application of this technique.

Recent Findings: LiTT has the potential to reduce the morbidity and discomfort of epilepsy surgery. Review of data from retrospective, uncontrolled studies suggests that LiTT may offer benefit when treating drug-resistant epilepsy because of mesial temporal sclerosis, hypothalamic hamartoma, cavernous hemangioma, and small cortical dysplasias and malformations. It is now being offered as initial therapy in place of anterior temporal lobectomy in many centers, and a prospective study is underway to compare it with historical temporal lobectomy reports.

Summary: LiTT appears promising and has potential for reduced morbidity and improved tolerability compared with open surgery. Studies must be done to compare efficacy and safety of LiTT with open surgery, and further investigation is needed to optimize this technique.
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http://dx.doi.org/10.1097/WCO.0000000000000662DOI Listing
April 2019

Hemispheric Regional Based Analysis of Diffusion Tensor Imaging and Diffusion Tensor Tractography in Patients with Temporal Lobe Epilepsy and Correlation with Patient outcomes.

Sci Rep 2019 01 18;9(1):215. Epub 2019 Jan 18.

Department of Neurosurgery, Thomas Jefferson University, Philadelphia, PA, USA.

Imaging in the field of epilepsy surgery remains an essential tool in terms of its ability to identify regions where the seizure focus might present as a resectable area. However, in many instances, an obvious structural abnormality is not visualized. This has created the opportunity for new approaches and imaging innovation in the field of epilepsy, such as with Diffusion Tensor Imaging (DTI) and Diffusion Tensor Tractography (DTT). In this study, we aim to evaluate the use of DTI and DTT as a predictive model in the field of epilepsy, specifically Temporal Lobe Epilepsy (TLE), and correlate their clinical significance with respect to postsurgical outcomes. A hemispheric based analysis was used to compare the tract density, as well as DTI indices of the specific regions of interest from the pathologic hemisphere to the healthy hemisphere in TLE patients. A total of 22 patients with TLE (12 males, 10 females, 22-57 age range) underwent either a craniotomy, Anterior Temporal Lobectomy (ATL), or a less invasive method of Selective Laser Amygdalohippocampectomy (SLAH) and were imaged using 3.0 T Philips Achieva MR scanner. Of the participants, 12 underwent SLAH while 10 underwent ATL. The study was approved by the institutional review board of Thomas Jefferson University Hospital. Informed consent was obtained from all patients. All patients had a diagnosis of TLE according to standard clinical criteria. DTI images were acquired axially in the same anatomical location prescribed for the T1-weighted images. The raw data set consisting of diffusion volumes were first corrected for eddy current distortions and motion artifacts. Various DTI indices such as Fractional Anisotropy (FA), Mean Diffusivity (MD), Radial Diffusivity (RD) and Axial Diffusivity (AD) were estimated and co-registered to the brain parcellation map obtained by freesurfer. 16 consolidated cortical and subcortical regions were selected as regions of interest (ROIs) by a functional neurosurgeon and DTI values for each ROI were calculated and compared with the corresponding ROI in the opposite hemisphere. Also, track density imaging (TDI) of 68 white matter parcels were generated using fiber orientation distribution (FOD) based deterministic fiber tracking and compared with contralateral side of the brain in each epileptic group: left mesial temporal sclerosis (LMTS) and right MTS (RMTS)). In patients with LMTS, MD and RD values of the left hippocampus decreased significantly using two-tailed t-test (p = 0.03 and p = 0.01 respectively) compared to the right hippocampus. Also, RD showed a marginally significant decrease in left amygdala (p = 0.05). DTT analysis in LMTS shows a marginally significant decrease in the left white matter supramarginal parcel (p = 0.05). In patients with RMTS, FA showed a significant decrease in the ipsilateral mesial temporal lobe (p = 0.02), parahippocampal area (p = 0.03) and thalamus (p = 0.006). RD showed a marginally significant increase in the ipsilateral hippocampus (p = 0.05) and a significant increase in the ipsilateral parahippocampal area (p = 0.03). Also, tract density of the ipsilateral white matter inferior parietal parcel showed a marginally significant increase compared to the contralateral side (p = 0.05). With respect to postsurgical outcomes, we found an association between residual seizures and tract density in five white matter segments including ipsilateral lingual (p = 0.04), ipsilateral temporal pole (p = 0.007), ipsilateral pars opercularis (p = 0.03), ipsilateral inferior parietal (p = 0.04) and contralateral frontal pole (p = 0.04). These results may have the potential to be developed into imaging prognostic markers of postoperative outcomes and provide new insights for why some patients with TLE continue to experience postoperative seizures if pathological/clinical correlates are further confirmed.
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http://dx.doi.org/10.1038/s41598-018-36818-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6338779PMC
January 2019

Clinically applicable delineation of the pallidal sensorimotor region in patients with advanced Parkinson's disease: study of probabilistic and deterministic tractography.

J Neurosurg 2018 Dec 1:1-12. Epub 2018 Dec 1.

Departments of1Radiology.

OBJECTIVEDeep brain stimulation (DBS) is an effective procedure in improving motor symptoms for patients with advanced Parkinson's disease (PD) through the use of high-frequency stimulation. Although one of the most commonly used target sites for DBS, sensorimotor regions of the globus pallidus interna (GPi) have yet to be thoroughly described with advanced neuroimaging analysis in vivo for human subjects. Furthermore, many imaging studies to date have been performed in a research setting and bring into question the feasibility of their applications in a clinical setting, such as for surgical planning. This study compares two different tractography methods applied to clinically feasible acquisition sequences in identifying sensorimotor regions of the GPi and the subthalamic nucleus (STN) in patients with advanced PD selected to undergo DBS.METHODSSeven patients with refractory PD selected for DBS were examined by MRI. Diffusion images were acquired with an average acquisition time of 15 minutes. Probabilistic and deterministic tractography methods were applied to each diffusion-weighted data set using FSL and MRtrix, respectively. Fiber assignment was performed using combined sensorimotor areas as initiation seeds and the STN and GPi, separately, as inclusion masks. Corticospinal tracts were excluded by setting the cerebral peduncles as exclusion masks. Variability between proposed techniques was shown using center of gravity (CoG) coordinates.RESULTSDeterministic and probabilistic corticopallidal and corticosubthalamic pathways were successfully reconstructed for all subjects across all target sites (bilaterally). Both techniques displayed large connections between the sensorimotor cortex with the posterolateral aspect of the ipsilateral GPi and the posterosuperolateral aspect of the ipsilateral STN. The average variability was 2.67 mm, with the probabilistic method identifying the CoG consistently more posterior and more lateral than the deterministic method.CONCLUSIONSSuccessful delineation of the sensorimotor regions in both the GPi and STN is achievable within a clinically reasonable timeframe. The techniques described in this paper may enhance presurgical planning with increased accuracy and improvement of patient outcomes in patients undergoing DBS. The variability found between tracking techniques warrants the use of the probabilistic tractography method over the deterministic method for presurgical planning. Probabilistic tractography was found to have an advantage over deterministic tractography in its sensitivity, in accurately describing previously described tracts, and in its ability to detect a larger number of fibers.
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http://dx.doi.org/10.3171/2018.7.JNS18541DOI Listing
December 2018

Chronically Implanted Intracranial Electrodes: Tissue Reaction and Electrical Changes.

Micromachines (Basel) 2018 Aug 25;9(9). Epub 2018 Aug 25.

Department of Neurological Surgery, Vickie and Jack Farber Institute for Neuroscience, Thomas Jefferson University Hospital, Philadelphia, PA 19107, USA.

The brain-electrode interface is arguably one of the most important areas of study in neuroscience today. A stronger foundation in this topic will allow us to probe the architecture of the brain in unprecedented functional detail and augment our ability to intervene in disease states. Over many years, significant progress has been made in this field, but some obstacles have remained elusive-notably preventing glial encapsulation and electrode degradation. In this review, we discuss the tissue response to electrode implantation on acute and chronic timescales, the electrical changes that occur in electrode systems over time, and strategies that are being investigated in order to minimize the tissue response to implantation and maximize functional electrode longevity. We also highlight the current and future clinical applications and relevance of electrode technology.
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http://dx.doi.org/10.3390/mi9090430DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6187588PMC
August 2018

Significant cephalad lead migration with use of externally powered spinal cord stimulator.

BMJ Case Rep 2018 Sep 21;2018. Epub 2018 Sep 21.

Neurosurgery, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.

Spinal cord stimulation has been an effective therapy for treatment of chronic low back pain over the last four decades. Over the years, there have been significant technological advances in the neuromodulation devices. Externally powered neuromodulation devices, that do not require an internal pulse generator (IPG) implantation, have recently been approved for treatment of chronic pain and the data on potential pitfalls and unforeseen complications with these devices is minimal. Here, we report a case of a 60-year-old woman with chronic back pain who underwent the implantation of one of such devices and developed complication that required neurosurgical intervention. The epidural stimulator leads in the patient migrated cranially to the T2 level that required extensive neurosurgical exploration. We believe this is the first reported case of such significant cranial epidural lead migration with the use of neurostimulation devices and demands more research into the safety of externally powered neurostimulation devices.
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http://dx.doi.org/10.1136/bcr-2018-225813DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6157503PMC
September 2018