Restoration of reaching and grasping movements through brain-controlled muscle stimulation in a person with tetraplegia: a proof-of-concept demonstration.

BACKGROUND: People with chronic tetraplegia, due to high-cervical spinal cord injury, can regain limb movements through coordinated electrical stimulation of peripheral muscles and nerves, known as functional electrical stimulation (FES). Users typically command FES systems through other preserved, but unrelated and limited in number, volitional movements (eg, facial muscle activity, head movements, shoulder shrugs). We report the findings of an individual with traumatic high-cervical spinal cord injury who coordinated reaching and grasping movements using his own paralysed arm and hand, reanimated through implanted FES, and commanded using his own cortical signals through an intracortical brain-computer interface (iBCI). METHODS: We recruited a participant into the BrainGate2 clinical trial, an ongoing study that obtains safety information regarding an intracortical neural interface device, and investigates the feasibility of people with tetraplegia controlling assistive devices using their cortical signals. Surgical procedures were performed at University Hospitals Cleveland Medical Center (Cleveland, OH, USA). Study procedures and data analyses were performed at Case Western Reserve University (Cleveland, OH, USA) and the US Department of Veterans Affairs, Louis Stokes Cleveland Veterans Affairs Medical Center (Cleveland, OH, USA). The study participant was a 53-year-old man with a spinal cord injury (cervical level 4, American Spinal Injury Association Impairment Scale category A). He received two intracortical microelectrode arrays in the hand area of his motor cortex, and 4 months and 9 months later received a total of 36 implanted percutaneous electrodes in his right upper and lower arm to electrically stimulate his hand, elbow, and shoulder muscles. The participant used a motorised mobile arm support for gravitational assistance and to provide humeral abduction and adduction under cortical control. We assessed the participant's ability to cortically command his paralysed arm to perform simple single-joint arm and hand movements and functionally meaningful multi-joint movements. We compared iBCI control of his paralysed arm with that of a virtual three-dimensional arm. This study is registered with ClinicalTrials.gov, number NCT00912041. FINDINGS: The intracortical implant occurred on Dec 1, 2014, and we are continuing to study the participant. The last session included in this report was Nov 7, 2016. The point-to-point target acquisition sessions began on Oct 8, 2015 (311 days after implant). The participant successfully cortically commanded single-joint and coordinated multi-joint arm movements for point-to-point target acquisitions (80-100% accuracy), using first a virtual arm and second his own arm animated by FES. Using his paralysed arm, the participant volitionally performed self-paced reaches to drink a mug of coffee (successfully completing 11 of 12 attempts within a single session 463 days after implant) and feed himself (717 days after implant). INTERPRETATION: To our knowledge, this is the first report of a combined implanted FES+iBCI neuroprosthesis for restoring both reaching and grasping movements to people with chronic tetraplegia due to spinal cord injury, and represents a major advance, with a clear translational path, for clinically viable neuroprostheses for restoration of reaching and grasping after paralysis. FUNDING: National Institutes of Health, Department of Veterans Affairs.

Visual-spatial memory may be enhanced with theta burst deep brain stimulation of the fornix: a preliminary investigation with four cases.

Memory loss after brain injury can be a source of considerable morbidity, but there are presently few therapeutic options for restoring memory function. We have previously demonstrated that burst stimulation of the fornix is able to significantly improve memory in a rodent model of traumatic brain injury. The present study is a preliminary investigation with a small group of cases to explore whether theta burst stimulation of the fornix might improve memory in humans. Four individuals undergoing stereo-electroencephalography evaluation for drug-resistant epilepsy were enrolled. All participants were implanted with an electrode into the proximal fornix and dorsal hippocampal commissure on the language dominant (n = 3) or language non-dominant (n = 1) side, and stimulation of this electrode reliably produced a diffuse evoked potential in the head and body of the ipsilateral hippocampus. Each participant underwent testing of verbal memory (Rey Auditory-Verbal Learning Test), visual-spatial memory (Medical College of Georgia Complex Figure Test), and visual confrontational naming (Boston Naming Test Short Form) once per day over at least two consecutive days using novel test forms each day. For 50% of the trials, the fornix electrode was continuously stimulated using a burst pattern (200 Hz in 100 ms trains, five trains per second, 100 µs, 7 mA) and was compared with sham stimulation. Participants and examiners were blinded to whether stimulation was active or not, and the order of stimulation was randomized. The small sample size precluded use of inferential statistics; therefore, data were analysed using descriptive statistics and graphic analysis. Burst stimulation of the fornix was not perceived by any of the participants but was associated with a robust reversible improvement in immediate and delayed performance on the Medical College of Georgia Complex Figure Test. There were no apparent differences on either Rey Auditory-Verbal Learning Test or Boston Naming Test. There was no apparent relationship between performance and side of stimulation (language dominant or non-dominant). There were no complications. Preliminary evidence in this small sample of patients with drug-resistant epilepsy suggests that theta burst stimulation of the fornix may be associated with improvement in visual-spatial memory.

Successful Management of Corneal Neuropathic Pain with Intrathecal Targeted Drug Delivery.

OBJECTIVE: To describe the successful treatment of refractory corneal neuropathic pain with neuromodulation techniques. DESIGN: Single case report. SETTING: Academic tertiary care center in the United States of America. SUBJECT AND METHODS: A 30-year-old woman presented with a 7-year history of refractory bilateral keratoneuralgia following laser-assisted in-situ keratomileusis (LASIK) procedure on both eyes. Having failed all conservative measures, the patient initially underwent trigeminal nerve stimulation and subsequently was implanted with an intrathecal drug delivery system (IDDS) with the catheter placed at the level C1. RESULTS: Following an initial favorable response to the trigeminal nerve stimulator, the pain became refractory to neurostimulation after a few months and the system was explanted. The patient was successfully trialed with an intrathecal catheter placed at the level of C1 delivering a combination of bupivacaine and low dose fentanyl. The patient was then implanted with an IDDS equipped with a patient-activated bolus system. The patient was very satisfied with the treatment and has had greater than 50% pain relief for over a year. CONCLUSIONS: Intrathecal delivery of bupivacaine and low dose fentanyl in the upper cervical spine can be effective in controlling refractory eye pain in properly selected patients and treatment centers.

Improved learning and memory with theta-burst stimulation of the fornix in rat model of traumatic brain injury.

OBJECTIVE: Learning and memory deficits are a source of considerable morbidity after traumatic brain injury (TBI). We investigated the effect of different patterns of hippocampal stimulation via a fornix electrode on cognitively demanding tasks after TBI. METHODS: Male Sprague-Dawley rats underwent fluid-percussion injury and were compared with sham-operated rats. Electrodes were implanted into the fornix and hippocampus, and stimulation of the fornix produced robust evoked potentials in the hippocampus. A 60-s delayed non-match-to-sample (DNMS) swim T-maze was serially performed using four stimulation patterns: no stimulation (No Stim), low-frequency stimulation (LFS, 5 Hz), high-frequency stimulation (HFS, 130 Hz), and theta-burst stimulation (TBS, 200 Hz in 50 ms trains, five trains per second; 60 µA biphasic pulses). In a separate cohort of sham and injured animals, Morris water maze (MWM) was performed with or without TBS. RESULTS: In the DNMS swim T-maze, LFS and HFS did not significantly improve performance after TBI. However, there was a significant difference in performance between TBI + No Stim and TBI + TBS groups (P < 0.05) with no significant difference between Sham + No Stim and TBI + TBS. In the MWM, latency in the TBI + TBS group was significantly different from TBI + No Stim starting on day 2 (P < 0.05) and was not different from Sham + No Stim. The TBI + TBS group performed significantly more platform crossings in the probe trial (P < 0.01) and exhibited improved search strategy starting on day 3 (P < 0.05) compared with TBI + No Stim. CONCLUSIONS: Deficits in learning and memory after TBI are improved with TBS of the hippocampus. HFS and LFS do not appear to produce as great an effect as TBS.

Improved Side-Effect Stimulation Thresholds and Postoperative Transient Confusion With Asleep, Image-Guided Deep Brain Stimulation.

BACKGROUND AND OBJECTIVES: Asleep, image-guided deep brain stimulation (DBS) is a modern alternative to awake, microelectrode recording (MER) guidance. Studies demonstrate comparable efficacy and complications between techniques, although some report lower stimulation thresholds for side effects with image guidance. In addition, few studies directly compare the risk of postoperative transient confusion (pTC) across techniques. The purpose of this study was to compare clinical efficacy, stimulation thresholds for side effects, and rates of pTC with MER-guided DBS vs intraoperative 3D-fluoroscopy (i3D-F) guidance in Parkinson's disease and essential tremor. METHODS: Consecutive patients from 2006 to 2021 were identified from the departmental database and grouped as having either MER-guided DBS or i3D-F-guided DBS insertion. Directional leads were used once commercially available. Changes in Unified Parkinson's Disease Rating Scale (UPDRS)-III scores, levodopa equivalent daily dose, Fahn-Tolosa-Marin scores, and stimulation thresholds were assessed, as were rates of complications including pTC. RESULTS: MER guidance was used to implant 487 electrodes (18 globus pallidus interna, GPi; 171 subthalamic nucleus; 76 ventrointermediate thalamus, VIM) in 265 patients. i3D-F guidance was used in 167 electrodes (19 GPi; 25 subthalamic nucleus; 41 VIM) in 85 patients. There were no significant differences in Unified Parkinson's Disease Rating III Scale, levodopa equivalent daily dose, or Fahn-Tolosa-Marin between groups. Stimulation thresholds for side effects were higher with i3D-F guidance in the subthalamic nucleus (MER, 2.80 mA ± 0.98; i3D-F, 3.46 mA ± 0.92; P = .002) and VIM (MER, 2.81 mA ± 1.00; i3D-F, 3.19 mA ± 1.03; P = .0018). Less pTC with i3D-F guidance (MER, 7.5%; i3D-F, 1.2%; P = .034) was also found. CONCLUSION: Although clinical efficacy between MER-guided and i3D-F-guided DBS was comparable, thresholds for stimulation side effects were higher with i3D-F guidance and the rate of pTC was lower. This suggests that image-guided DBS may affect long-term side effects and pose a decreased risk of pTC.

Reconnecting the Hand and Arm to the Brain: Efficacy of Neural Interfaces for Sensorimotor Restoration After Tetraplegia.

BACKGROUND AND OBJECTIVES: Paralysis after spinal cord injury involves damage to pathways that connect neurons in the brain to peripheral nerves in the limbs. Re-establishing this communication using neural interfaces has the potential to bridge the gap and restore upper extremity function to people with high tetraplegia. We report a novel approach for restoring upper extremity function using selective peripheral nerve stimulation controlled by intracortical microelectrode recordings from sensorimotor networks, along with restoration of tactile sensation of the hand using intracortical microstimulation. METHODS: A 27-year-old right-handed man with AIS-B (motor-complete, sensory-incomplete) C3-C4 tetraplegia was enrolled into the clinical trial. Six 64-channel intracortical microelectrode arrays were implanted into left hemisphere regions involved in upper extremity function, including primary motor and sensory cortices, inferior frontal gyrus, and anterior intraparietal area. Nine 16-channel extraneural peripheral nerve electrodes were implanted to allow targeted stimulation of right median, ulnar (2), radial, axillary, musculocutaneous, suprascapular, lateral pectoral, and long thoracic nerves, to produce selective muscle contractions on demand. Proof-of-concept studies were performed to demonstrate feasibility of using a brain-machine interface to read from and write to the brain for restoring motor and sensory functions of the participant's own arm and hand. RESULTS: Multiunit neural activity that correlated with intended motor action was successfully recorded from intracortical arrays. Microstimulation of electrodes in somatosensory cortex produced repeatable sensory percepts of individual fingers for restoration of touch sensation. Selective electrical activation of peripheral nerves produced antigravity muscle contractions, resulting in functional movements that the participant was able to command under brain control to perform virtual and actual arm and hand movements. The system was well tolerated with no operative complications. CONCLUSION: The combination of implanted cortical electrodes and nerve cuff electrodes has the potential to create bidirectional restoration of motor and sensory functions of the arm and hand after neurological injury.

Depths and grids in brain tumors: implantation strategies, techniques, and complications.

Patients with intracranial mass lesions are at increased risk of intractable epilepsy even after tumor resection due to the potential epileptogenicity of lesional and perilesional tissue. Risk factors for tumoral epilepsy include tumor location, histology, and extent of tumor resection. In epilepsy that occurs after tumor resection, the epileptogenic zone often does not correspond precisely with the area of abnormality on imaging, and seizures often arise from a relatively restricted area despite widespread changes on imaging. Invasive monitoring via subdural grids and/or depth electrodes can therefore be helpful to delineate areas of eloquence and localize the epileptogenic zone for subsequent resection. Subdural grids offer excellent contiguous coverage of superficial cortex and allow resection using the same craniotomy, facilitating understanding of anatomic relationships. Depth electrodes offer superior coverage of deep structures, are easier to use in cases where a previous craniotomy is present, are not associated with anatomic distortion due to brain shift, and may be associated with a lower complication rate. We review the biology of focal postoperative epilepsy and invasive diagnostic strategies for the surgical evaluation of medically refractory epilepsy in patients who have undergone resection of intracranial mass lesions.

Current Applications of Ablative Therapies for Trigeminal Neuralgia.

Trigeminal neuralgia (TN) is a syndrome consisting of episodic neuropathic facial pain. Although the precise symptoms vary across individuals, TN is typically described as lancinating electrical shocks triggered by sensory stimuli (light touch, talking, eating, and brushing teeth) that improve with antiepileptic medication (especially carbamazepine), remit spontaneously for weeks to months (pain-free intervals), and do not involve any changes in baseline sensation. The etiology of TN has not been definitively established, but many cases are associated with compression of the trigeminal nerve by a blood vessel at the trigeminal root entry zone adjacent to the brainstem. Patients who do not respond to medical management and who are not candidates for microvascular decompression often benefit from focal therapeutic injury to the trigeminal nerve at some point along its course. Many lesions have been described, including peripheral neurectomies that target distal branches of the trigeminal nerve, rhizotomies of the Gasserian ganglion of the nerve within Meckel's cave, radiosurgery of the trigeminal nerve at its root entry zone, partial sensory rhizotomy at the root entry zone, tractotomy of the spinal nucleus of the trigeminal nerve, and DREZotomy of the trigeminal nucleus caudalis, Though the latter two interventions are seldom done for TN and more commonly performed for trigeminal neuropathic pain. This article reviews the relevant anatomy and lesioning procedures for the treatment of trigeminal neuralgia.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines for Occipital Nerve Stimulation for the Treatment of Patients With Medically Refractory Occipital Neuralgia: Update.

BACKGROUND: The Guidelines Task Force conducted a systematic review of the relevant literature on occipital nerve stimulation (ONS) for occipital neuralgia (ON) to update the original 2015 guidelines to ensure timeliness and accuracy for clinical practice. OBJECTIVE: To conduct a systematic review of the literature and update the evidence-based guidelines on ONS for ON. METHODS: The Guidelines Task Force conducted another systematic review of the relevant literature, using the same search terms and strategies used to search PubMed and Embase for relevant literature. The updated search included studies published between 1966 and January 2023. The same inclusion/exclusion criteria as the original guideline were also applied. Abstracts were reviewed, and relevant full text articles were retrieved and graded. Of 307 articles, 18 were retrieved for full-text review and analysis. Recommendations were updated according to new evidence yielded by this update . RESULTS: Nine studies were included in the original guideline, reporting the use of ONS as an effective treatment option for patients with medically refractory ON. An additional 6 studies were included in this update. All studies in the original guideline and this current update provide Class III evidence. CONCLUSION: Based on the availability of new literature, the current article is a minor update only that does not result in modification of the prior recommendations: Clinicians may use ONS as a treatment option for patients with medically refractory ON.

Interim Safety Profile From the Feasibility Study of the BrainGate Neural Interface System.

BACKGROUND AND OBJECTIVES: Brain-computer interfaces (BCIs) are being developed to restore mobility, communication, and functional independence to people with paralysis. Though supported by decades of preclinical data, the safety of chronically implanted microelectrode array BCIs in humans is unknown. We report safety results from the prospective, open-label, nonrandomized BrainGate feasibility study (NCT00912041), the largest and longest-running clinical trial of an implanted BCI. METHODS: Adults aged 18-75 years with quadriparesis from spinal cord injury, brainstem stroke, or motor neuron disease were enrolled through 7 clinical sites in the United States. Participants underwent surgical implantation of 1 or 2 microelectrode arrays in the motor cortex of the dominant cerebral hemisphere. The primary safety outcome was device-related serious adverse events (SAEs) requiring device explantation or resulting in death or permanently increased disability during the 1-year postimplant evaluation period. The secondary outcomes included the type and frequency of other adverse events and the feasibility of the BrainGate system for controlling a computer or other assistive technologies. RESULTS: From 2004 to 2021, 14 adults enrolled in the BrainGate trial had devices surgically implanted. The average duration of device implantation was 872 days, yielding 12,203 days of safety experience. There were 68 device-related adverse events, including 6 device-related SAEs. The most common device-related adverse event was skin irritation around the percutaneous pedestal. There were no safety events that required device explantation, no unanticipated adverse device events, no intracranial infections, and no participant deaths or adverse events resulting in permanently increased disability related to the investigational device. DISCUSSION: The BrainGate Neural Interface system has a safety record comparable with other chronically implanted medical devices. Given rapid recent advances in this technology and continued performance gains, these data suggest a favorable risk/benefit ratio in appropriately selected individuals to support ongoing research and development. TRIAL REGISTRATION INFORMATION: ClinicalTrials.gov Identifier: NCT00912041. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that the neurosurgically placed BrainGate Neural Interface system is associated with a low rate of SAEs defined as those requiring device explantation, resulting in death, or resulting in permanently increased disability during the 1-year postimplant period.

Future directions in psychiatric neurosurgery: Proceedings of the 2022 American Society for Stereotactic and Functional Neurosurgery meeting on surgical neuromodulation for psychiatric disorders.

OBJECTIVE: Despite advances in the treatment of psychiatric diseases, currently available therapies do not provide sufficient and durable relief for as many as 30-40% of patients. Neuromodulation, including deep brain stimulation (DBS), has emerged as a potential therapy for persistent disabling disease, however it has not yet gained widespread adoption. In 2016, the American Society for Stereotactic and Functional Neurosurgery (ASSFN) convened a meeting with leaders in the field to discuss a roadmap for the path forward. A follow-up meeting in 2022 aimed to review the current state of the field and to identify critical barriers and milestones for progress. DESIGN: The ASSFN convened a meeting on June 3, 2022 in Atlanta, Georgia and included leaders from the fields of neurology, neurosurgery, and psychiatry along with colleagues from industry, government, ethics, and law. The goal was to review the current state of the field, assess for advances or setbacks in the interim six years, and suggest a future path forward. The participants focused on five areas of interest: interdisciplinary engagement, regulatory pathways and trial design, disease biomarkers, ethics of psychiatric surgery, and resource allocation/prioritization. The proceedings are summarized here. CONCLUSION: The field of surgical psychiatry has made significant progress since our last expert meeting. Although weakness and threats to the development of novel surgical therapies exist, the identified strengths and opportunities promise to move the field through methodically rigorous and biologically-based approaches. The experts agree that ethics, law, patient engagement, and multidisciplinary teams will be critical to any potential growth in this area.

Relapsed acute myelogenous leukemia of brachial plexus after marrow transplant.

We present a detailed description of brachial plexus infiltration by acute myelogenous leukemia (AML) in the setting of a remission bone marrow biopsy, without evidence of leukemia by flow cytometric analysis. This case illustrates the possibility of dormant leukemic cells in the peripheral nervous system (PNS) in a patient in apparent clinical remission. In patients with an unexplained brachial plexopathy and a history of AML, leukemic infiltrate of the PNS must be considered.

Best practices for the pregnant neurosurgical resident: balancing safety and education.

Establishment of a diverse neurosurgical workforce includes increasing the recruitment of women in neurosurgery. The impact of pregnancy on the training and career trajectory of female neurosurgeons poses a barrier to recruitment and retention of women in neurosurgery. A recent Women in Neurosurgery survey evaluated female neurosurgeons' perception and experience regarding childbearing of female neurosurgeons and identified several recommendations regarding family leave policies. Additionally, pregnancy may carry higher risk in surgical fields, yet little guidance exists to aid both the pregnant resident and her training program in optimizing the safety of the training environment with specific considerations to risks inherent in neurosurgical training. This review of current literature aims to address best practices that can be adopted by pregnant neurosurgery residents and their training programs to improve the well-being of these residents while considering the impact on their education and the educational environment for their colleagues.

Cingulum bundle connectivity in treatment-refractory compared to treatment-responsive patients with bipolar disorder and healthy controls: a tractography and surgical targeting analysis.

OBJECTIVE: The clinical response of patients with bipolar disorder to medical treatment is variable. A better understanding of the underlying neural circuitry involved in bipolar treatment responsivity subtypes may provide insight into treatment resistance and aid in identifying an effective surgical target for deep brain stimulation (DBS) specific to the disorder. Despite considerable imaging research related to the disease, a paucity of comparative imaging analyses of treatment responsiveness exists. There are also no DBS targets designed expressly for patients with bipolar disorder. Therefore, the authors analyzed cingulum bundle axonal connectivity in relation to cortico-striatal-thalamo-cortical (CSTC) loops implicated in bipolar disorder across subjects who are responsive to treatment (RSP) and those who are refractory to therapy (REF), compared to healthy controls (HCs). METHODS: Twenty-five subjects with bipolar disorder (13 RSP and 12 REF), diagnosed using the Mini International Neuropsychiatric Interview and classified with standardized rating scales, and 14 HCs underwent MRI with diffusion sequences for probabilistic diffusion-weighted tractography analysis. Image processing and tractography were performed using MRTrix. Region of interest (ROI) masks were created manually for 10 anterior cingulum bundle subregions, including surgical targets previously evaluated for the treatment of bipolar disorder (cingulotomy and subgenual cingulate DBS targets). Cortical and subcortical ROIs of brain areas thought to be associated with bipolar disorder and described in animal tract-tracing models were created via FreeSurfer. The number of axonal projections from the cingulum bundle subregion ROIs to cortical/subcortical ROIs for each group was compared. RESULTS: Significant differences were found across groups involving cingulum bundle and CSTC loops. Subjects in the RSP group had increased connections from rostral cingulum bundle to medial orbitofrontal cortex, which is part of the limbic CSTC loop, whereas subjects in the REF group had increased connectivity from rostral cingulum bundle to thalamus. Additionally, compared to HCs, both RSP and REF subjects had decreased cingulum bundle dorsal connectivity (dorsal anterior/posterior cingulate, dorsomedial/lateral frontal cortex) and increased cingulum bundle ventral connectivity (subgenual cingulate, frontal pole, lateral orbitofrontal cortex) involving limbic and associative CSTC loops. CONCLUSIONS: Findings demonstrate that bipolar treatment responsivity may be associated with significant differences in cingulum bundle connectivity in relation to CSTC loops, which may help identify a surgical target for bipolar disorder treatment via DBS in the future.

Connectivity-based identification of a potential neurosurgical target for mood disorders.

OBJECTIVE: Stereotactic ablation (cingulotomy) and subcallosal cingulate deep brain stimulation (SCC DBS) of different regions of the cingulum bundle (CB) have been successfully used to treat psychiatric disorders, such as depression and bipolar disorder. They are hypothesized to work by disrupting white matter pathways involved in the clinical manifestation of these disorders. This study aims to compare the connectivity of different CB subregions using tractography to evaluate stereotactic targets for the treatment of mood disorders. METHODS: Fourteen healthy volunteers underwent 3T-MR imaging followed by connectivity analysis using probabilistic tractography. Twenty-one anatomic regions of interest were defined for each subject: 10 CB subregions (including the classical cingulotomy and SCC DBS targets) and 11 cortical/subcortical structures implicated in mood disorders. Connectivity results were compared using Friedman and Bonferroni-corrected post-hoc Wilcoxon tests. RESULTS: CB connectivity showed a high degree of regional specificity. Both of the traditional stereotactic targets had widespread connectivity with discrete topology. The cingulotomy target connected primarily to the dorsomedial frontal, dorsal anterior cingulate, and posterior cingulate cortices, whereas the SCC DBS target connected mostly to the subgenual anterior cingulate and medial/central orbitofrontal cortices. However, a region of the rostral dorsal CB, lying between these surgical targets, encompassed statistically equivalent connections to all five cortical regions. CONCLUSIONS: The CB is associated with brain structures involved in affective disorders, and the rostral dorsal CB demonstrates connectivity that is comparable to the combined connectivity of cingulotomy and SCC DBS neurosurgical interventions. The rostral dorsal CB represents a surgical target worthy of clinical exploration for mood disorders.

Clinical Evaluation of Cingulum Bundle Connectivity for Neurosurgical Hypothesis Development.

BACKGROUND: The cingulum bundle (CB) has long been a target for psychiatric neurosurgical procedures, but with limited understanding of the brain networks being impacted. Recent advances in human tractography could provide a foundation to better understand the effects of neurosurgical interventions on the CB; however, the reliability of tractography remains in question. OBJECTIVE: To evaluate the ability of different tractography techniques, derived from typical, human diffusion-weighted imaging (DWI) data, to characterize CB connectivity described in animal models. This will help validate the clinical applicability of tractography, and generate insight on current and future neurosurgical targets for psychiatric disorders. METHODS: Connectivity of the CB in 15 healthy human subjects was evaluated using DWI-based tractography, and compared to tract-tracing findings from nonhuman primates. Brain regions of interest were defined to coincide with the animal model. Tractography was performed using 3 techniques (FSL probabilistic, Camino probabilistic, and Camino deterministic). Differences in connectivity were assessed, and the CB segment with the greatest connectivity was determined. RESULTS: Each tractography technique successfully reproduced the animal tracing model with a mean accuracy of 72% (68-75%, P < .05). Additionally, one region of the CB, the rostral dorsal segment, had significantly greater connectivity to associated brain structures than all other CB segments (P < .05). CONCLUSION: Noninvasive, in vivo human analysis of the CB, using clinically available DWI for tractography, consistently reproduced the results of an animal tract-tracing model. This suggests that tractography of the CB can be used for clinical applications, which may aid in neurosurgical targeting for psychiatric disorders.

Pregnancy and parental leave among neurosurgeons and neurosurgical trainees.

OBJECTIVE: Despite recently heightened advocacy efforts relating to pregnancy and family leave policies in multiple surgical specialties, no studies to date have described female neurosurgeons' experiences with childbearing. The AANS/CNS Section of Women in Neurosurgery created the Women and Pregnancy Task Force to ascertain female neurosurgeons' experiences with and attitudes toward pregnancy and the role of family leave policies. METHODS: A voluntary online 28-question survey examined the pregnancy experiences of female neurosurgeons and perceived barriers to childbearing. The survey was developed and electronically distributed to all members of the American Association of Neurological Surgeons and Congress of Neurological Surgeons who self-identified as female in February 2016. Responses from female resident physicians, fellows, and current or retired practicing neurosurgeons were analyzed. RESULTS: A total of 126 women (20.3%) responded to the survey; 57 participants (49%) already had children, and 39 (33%) planned to do so. Participants overwhelmingly had or planned to have children during the early practice and senior residency years. The most frequent obstacles experienced or anticipated included insufficient time to care for newborns (47% of women with children, 92% of women planning to have children), discrimination by coworkers (31% and 77%, respectively), and inadequate time for completion of board requirements (18% and 51%, respectively). There was substantial variability in family leave policies, and a minority of participants (35%) endorsed the presence of any formal policy at their institution. Respondents described myriad unique challenges associated with pregnancy and family leave. CONCLUSIONS: Pregnancy and family leave pose significant challenges to the recruitment, retention, and advancement of women in neurosurgery. It is thus imperative to promote clear family leave policies for trainees and practitioners, address discrimination surrounding these topics, and encourage forethought and flexibility to tackle obstacles inherent in pregnancy and the early stages of child rearing.

Neural Representation of Observed, Imagined, and Attempted Grasping Force in Motor Cortex of Individuals with Chronic Tetraplegia.

Hybrid kinetic and kinematic intracortical brain-computer interfaces (iBCIs) have the potential to restore functional grasping and object interaction capabilities in individuals with tetraplegia. This requires an understanding of how kinetic information is represented in neural activity, and how this representation is affected by non-motor parameters such as volitional state (VoS), namely, whether one observes, imagines, or attempts an action. To this end, this work investigates how motor cortical neural activity changes when three human participants with tetraplegia observe, imagine, and attempt to produce three discrete hand grasping forces with the dominant hand. We show that force representation follows the same VoS-related trends as previously shown for directional arm movements; namely, that attempted force production recruits more neural activity compared to observed or imagined force production. Additionally, VoS-modulated neural activity to a greater extent than grasping force. Neural representation of forces was lower than expected, possibly due to compromised somatosensory pathways in individuals with tetraplegia, which have been shown to influence motor cortical activity. Nevertheless, attempted forces (but not always observed or imagined forces) could be decoded significantly above chance, thereby potentially providing relevant information towards the development of a hybrid kinetic and kinematic iBCI.

Evolution in the Treatment of Psychiatric Disorders: From Psychosurgery to Psychopharmacology to Neuromodulation.

The treatment of psychiatric patients presents significant challenges to the clinical community, and a multidisciplinary approach to diagnosis and management is essential to facilitate optimal care. In particular, the neurosurgical treatment of psychiatric disorders, or "psychosurgery," has held fascination throughout human history as a potential method of influencing behavior and consciousness. Early evidence of such procedures can be traced to prehistory, and interest flourished in the nineteenth and early twentieth century with greater insight into cerebral functional and anatomic localization. However, any discussion of psychosurgery invariably invokes controversy, as the widespread and indiscriminate use of the transorbital lobotomy in the mid-twentieth century resulted in profound ethical ramifications that persist to this day. The concurrent development of effective psychopharmacological treatments virtually eliminated the need and desire for psychosurgical procedures, and accordingly the research and practice of psychosurgery was dormant, but not forgotten. There has been a recent resurgence of interest for non-ablative therapies, due in part to modern advances in functional and structural neuroimaging and neuromodulation technology. In particular, deep brain stimulation is a promising treatment paradigm with the potential to modulate abnormal pathways and networks implicated in psychiatric disease states. Although there is enthusiasm regarding these recent advancements, it is important to reflect on the scientific, social, and ethical considerations of this controversial field.