Preventing Sudden Cessation of Implantable Pulse Generators in Deep Brain Stimulation: A Systematic Review and Protocol Proposal.

INTRODUCTION: Deep brain stimulation (DBS) requires a consistent electrical supply from the implantable pulse generator (IPG). Patients may struggle to monitor their IPG, risking severe complications in battery failure. This review assesses current literature on DBS IPG battery life management and proposes a protocol for healthcare providers. METHODS: A literature search using four databases identified best practices for DBS IPG management. Studies were appraised for IPG management guidelines, categorized as qualitative, quantitative, or both. RESULTS: Of 408 citations, only seven studies were eligible, none providing clear patient management strategies. Current guidelines lack specificity, relying on clinician suggestions. CONCLUSION: Limited guidelines exist for IPG management. Specificity and adaptability to emerging technology are crucial. The findings highlight the need for specificity in patients' needs and adaptability to emerging technology in future studies. To address this need, we developed a protocol for DBS IPG management that we have implemented at our own institution. Further research is needed for effective DBS IPG battery life management, preventing therapy cessation complications.

Enhancing epidural needle guidance using a polarization-sensitive optical coherence tomography probe with convolutional neural networks.

Epidural anesthesia helps manage pain during different surgeries. Nonetheless, the precise placement of the epidural needle remains a challenge. In this study, we developed a probe based on polarization-sensitive optical coherence tomography (PS-OCT) to enhance the epidural anesthesia needle placement. The probe was tested on six porcine spinal samples. The multimodal imaging guidance used the OCT intensity mode and three distinct PS-OCT modes: (1) phase retardation, (2) optic axis, and (3) degree of polarization uniformity (DOPU). Each mode enabled the classification of different epidural tissues through distinct imaging characteristics. To further streamline the tissue recognition procedure, convolutional neural network (CNN) were used to autonomously identify the tissue types within the probe's field of view. ResNet50 models were developed for all four imaging modes. DOPU imaging was found to provide the highest cross-testing accuracy of 91.53%. These results showed the improved precision by PS-OCT in guiding epidural anesthesia needle placement.

A parcellation-based connectomic model of hemispatial neglect.

BACKGROUND AND PURPOSE: Hemispatial neglect is characterized by a reduced awareness to stimuli on the contralateral side. Current literature suggesting that damage to the right parietal lobe and attention networks may cause hemispatial neglect is conflicting and can be improved by investigating a connectomic model of the "neglect system" and the anatomical specificity of regions involved in it. METHODS: A meta-analysis of voxel-based morphometry magnetic resonance imaging (MRI) studies of hemispatial neglect was used to identify regions associated with neglect. We applied parcellation schemes to these regions and performed diffusion spectrum imaging (DSI) tractography to determine their connectivity. By overlaying neglect areas and maps of the attention networks, we studied the relationship between them. RESULTS: The meta-analysis generated a list of 13 right hemisphere parcellations. These 13 neglect-related parcellations were predominantly linked by the superior longitudinal fasciculus (SLF) throughout a fronto-parietal-temporal network. We found that the dorsal and ventral attention networks showed partial overlap with the neglect system and included various other higher-order networks. CONCLUSIONS: We provide an anatomically specific connectomic model of the neurobehavioral substrates underlying hemispatial neglect. Our model suggests a fronto-parietal-temporal network linked via the SLF supports the functions impaired in neglect and implicates various higher-order networks which are not limited to the attention networks.

Deep brain stimulation in a pediatric dystonia patient with cochlear implants and mitochondrial disorder: novel application of a frameless stereotactic system and navigating the anesthesia choice and neurosurgical complexities. Illustrative case.

BACKGROUND: This report presents a case of medically refractory dystonia in a pediatric patient successfully treated with bilateral subthalamic nucleus (STN) deep brain stimulation (DBS) while under general anesthesia by using microelectrode recordings (MERs) with intraoperative computed tomography (CT). OBSERVATIONS: The patient was an 18-year-old female with primary dystonia secondary to mitochondrial Leigh syndrome. Her past medical history was significant for complex partial epilepsy and hearing loss treated with cochlear implants. Her cochlear implants precluded anatomical targeting via magnetic resonance imaging. Additionally, the patient could not tolerate awake surgery with MER. The decision was made to proceed with bilateral STN DBS with intraoperative CT with the patient under general anesthesia. The patient's cochlear implants made standard frame placement difficult, so navigation was performed with the Nexframe system. Recordings were obtained with the patient under general anesthesia with ketamine, dexmedetomidine, and remifentanil. At the 3- and 6-month follow-ups, the patient demonstrated marked improvement in dystonia without neurological complications. LESSONS: This is the first case of dystonia secondary to Leigh syndrome treated with DBS. Additionally, the authors describe the novel use of the Nexframe for DBS lead placement in a pediatric patient. This demonstrates that STN DBS with the use of MER and intraoperative CT can be a safe and effective method of treating dystonia in certain pediatric patients.

Prolactinoma extension as a contributing factor in dopamine agonist-induced CSF rhinorrhea: a systematic review of the literature.

BACKGROUND: Dopamine agonist-induced cerebrospinal fluid (CSF) rhinorrhea is an uncommon treatment-related complication arising in 6.1% of prolactinoma patients treated with dopamine agonists. Locally invasive prolactinomas may create CSF fistulae through formation of dural and osseous skull base defects. Tumor shrinkage secondary to dopamine agonist therapy unmasks skull base defects, thus inducing CSF rhinorrhea. In these cases, repair of the leak may be achieved through collaborative surgical intervention by rhinologists and neurosurgeons. Multiple variables have been investigated as potential contributors to the risk of CSF rhinorrhea development in medically treated prolactinoma patients, with little consensus. OBJECTIVE: The primary aim of our study was the characterization of risk factors for CSF rhinorrhea development following dopamine agonist treatment. METHODS: A systematic review of the literature was conducted to identify cases of CSF rhinorrhea following dopamine agonist treatment of prolactinoma. The clinical history, radiographic findings and treatment outcomes are discussed. RESULTS: Fifty-four patients with dopamine agonist-induced CSF rhinorrhea were identified across 23 articles published from 1979 to 2019. Description of diagnostic imaging [computed tomography (CT)/magnetic resonance imaging (MRI)] was not provided for 18/54 subjects. For the 36 cases that described prolactinoma appearance on CT or MRI, invasion of the cavernous sinuses was reported in 13 (36.1%) and invasion of the sphenoid sinus was reported in 18 (50%). CONCLUSION: Based on our systematic review, we propose that CT findings of osseous erosion of the sella or the anterior skull base may predict dopamine agonist-induced CSF rhinorrhea. We recommend obtaining a thin-slice CT of the sinuses in cases with MRI evidence of sphenoid involvement.

Delayed hemorrhage following deep brain stimulation device placement in a patient with Parkinson's disease and lupus anticoagulant syndrome: illustrative case.

BACKGROUND: Treatment options for Parkinson's disease (PD) include both medical and surgical approaches. Deep brain stimulation (DBS) is a surgical procedure that aims to improve motor symptomatology. OBSERVATIONS: A 66-year-old White male with a 9-year history of PD presented to the neurosurgery clinic for DBS consideration. On the morning of scheduled surgery, preoperative laboratory test results revealed a prolonged prothrombin time of 50 seconds. Surgery was postponed, and further work-up revealed that the patient had a positive test result for lupus anticoagulant (LA). DBS implantation was performed 2 months later. The first stage of surgery was uneventful. The patient returned 1 week later for the second stage. Postoperatively, the patient exhibited a diminished level of consciousness. Computed tomography revealed left frontal intraparenchymal hemorrhage with surrounding edema, trace subarachnoid hemorrhage, intraventricular hemorrhage, and midline shift. LESSONS: The authors suspect that the hemorrhage occurred secondary to venous infarct, because LA is associated with a paradoxically increased risk of thrombosis. Although there is no documented association between LA and acute or delayed hemorrhage, this case demonstrates a possible relationship in a patient following DBS placement. More research is needed to confirm an association with coexisting LA with PD and an increased hemorrhage risk in neurosurgical interventions.

Management of nonoperative cervical spine fractures: An institutional analysis of follow-up duration and image acquisition.

Background: How long do nonoperative cervical fractures have to be followed and with how many imaging studies? Methods: We reviewed 69 adult patients with 122 (31 occiptocervical and 91 sub-axial) cervical fractures; at least one of the cervical fractures was managed nonoperatively. Outcomes were assessed along with the optimal follow-up duration and frequency of various diagnostic studies. Results: An average of four follow-up visits occurred on average 28-, 66-, 94-, and 158-day post hospital discharge. The average time between discharge and orthotic clearance was 70 days (±32.4 days). Radiographic studies were obtained at follow-up visits, respectively, in, 82.6%, 83.6%, 94.7%, and 100% of patients. Conclusion: The trend for managing nonoperative cervical fractures was an unduly prolonged follow-up duration that included obtaining too many imaging studies.

Parcellation-based tractographic modeling of the salience network through meta-analysis.

BACKGROUND: The salience network (SN) is a transitory mediator between active and passive states of mind. Multiple cortical areas, including the opercular, insular, and cingulate cortices have been linked in this processing, though knowledge of network connectivity has been devoid of structural specificity. OBJECTIVE: The current study sought to create an anatomically specific connectivity model of the neural substrates involved in the salience network. METHODS: A literature search of PubMed and BrainMap Sleuth was conducted for resting-state and task-based fMRI studies relevant to the salience network according to PRISMA guidelines. Publicly available meta-analytic software was utilized to extract relevant fMRI data for the creation of an activation likelihood estimation (ALE) map and relevant parcellations from the human connectome project overlapping with the ALE data were identified for inclusion in our SN model. DSI-based fiber tractography was then performed on publicaly available data from healthy subjects to determine the structural connections between cortical parcellations comprising the network. RESULTS: Nine cortical regions were found to comprise the salience network: areas AVI (anterior ventral insula), MI (middle insula), FOP4 (frontal operculum 4), FOP5 (frontal operculum 5), a24pr (anterior 24 prime), a32pr (anterior 32 prime), p32pr (posterior 32 prime), and SCEF (supplementary and cingulate eye field), and 46. The frontal aslant tract was found to connect the opercular-insular cluster to the middle cingulate clusters of the network, while mostly short U-fibers connected adjacent nodes of the network. CONCLUSION: Here we provide an anatomically specific connectivity model of the neural substrates involved in the salience network. These results may serve as an empiric basis for clinical translation in this region and for future study which seeks to expand our understanding of how specific neural substrates are involved in salience processing and guide subsequent human behavior.

Practice Patterns of Ventriculoperitoneal Shunt Placement in Academic and Community Settings: A National Survey of Practicing Neurosurgeons.

OBJECTIVE: We sought to assess the practice patterns of ventriculoperitoneal shunt (VPS) placement by neurosurgeons at academic, community, and government-based institutions. METHODS: Using the American Association of Neurological Surgeons directory, a total of 3673 practicing neurosurgeons were contacted. The survey received 495 responses (57% academic, 41% community, 3% other/government based). The survey consisted of 9 questions to assess the frequency of general surgery assistance for distal VPS placement and the use of cranial neuronavigation for proximal placement and to assess subjective beliefs of personal practice pattern and the influence on shunt failure rates. RESULTS: Almost half of the respondents reported using general surgery less than half of the time for distal VPS placement. Regardless of personal practice patterns, roughly one third of respondents reported that general surgery assistance is a common or somewhat common practice at their institution. The most common reasons for recruiting general surgery assistance were cases of higher complexity. Although commonly used, almost 40% of respondents believe that general surgery assistance does not decrease shunt failure rates. Cranial neuronavigation is used less than half of the time, and the most common reason was for improved accuracy. Almost half of the respondents believe navigation does decrease shunt failure rates. CONCLUSIONS: General surgery assistance for distal placement and neuronavigation for the proximal placement of VPS catheters are both commonly used by neurosurgeons in academic, community, and other practice locations. This survey provides the first assessment of practice patterns nationally. The results demonstrate that roughly half of the practicing neurosurgeons use general surgery assistance and neuronavigation, particularly for complex or high-risk cases.

Primary Repair of Posteriorly Located Anterior Skull Base Dural Defects Using Nonpenetrating Titanium Clips in Cranial Trauma.

Objective Primary repair of posteriorly located anterior skull base (ASB) dural defects following cranial trauma is made difficult by narrow operative corridors and adherent dura mater. Inadequate closure may result in continued cerebrospinal fluid (CSF) leak and infectious sequelae. Here, we report surgical outcomes following the use of nonpenetrating titanium microclips as an adjunctive repair technique in traumatic anterior skull base dural defects extending from the olfactory groove to the tuberculum sellae. Methods All trauma patients who underwent a bifrontal craniotomy from January 2013 to October 2019 were retrospectively reviewed. Patients with ASB defects located at posterior to the olfactory groove were analyzed. Patients with isolated frontal sinus fractures were excluded. All patients presented with CSF leak or radiographic signs of dural compromise. Patients were divided according to posterior extent of injury. Patient characteristics, imaging, surgical technique, and outcomes are reported. Results A total of 19 patients who underwent a bifrontal craniotomy for repair of posteriorly located ASB dural defects using nonpenetrating titanium microclips were included. Defects were divided by location: olfactory groove (10/19), planum sphenoidale (6/19), and tuberculum sellae (3/19). No patients demonstrated a postoperative CSF leak. No complications related to the microclip technique was observed. Clip artifact did not compromise postoperative imaging interpretation. Conclusion Primary repair of posteriorly located ASB dural defects is challenging due to narrow working angles and thin dura mater. Use of nonpenetrating titanium microclips for primary repair of posteriorly located dural defects is a reasonable adjunctive repair technique and was associated with no postoperative CSF leaks in this cohort.

A systematic review of amino acid PET in assessing treatment response to temozolomide in glioma.

The response assessment in neuro-oncology (RANO) criteria have been the gold standard for monitoring treatment response in glioblastoma (GBM) and differentiating tumor progression from pseudoprogression. While the RANO criteria have played a key role in detecting early tumor progression, their ability to identify pseudoprogression is limited by post-treatment damage to the blood-brain barrier (BBB), which often leads to contrast enhancement on MRI and correlates poorly to tumor status. Amino acid positron emission tomography (AA PET) is a rapidly growing imaging modality in neuro-oncology. While contrast-enhanced MRI relies on leaky vascularity or a compromised BBB for delivery of contrast agents, amino acid tracers can cross the BBB, making AA PET particularly well-suited for monitoring treatment response and diagnosing pseudoprogression. The authors performed a systematic review of PubMed, MEDLINE, and Embase through December 2021 with the search terms "temozolomide" OR "Temodar," "glioma" OR "glioblastoma," "PET," and "amino acid." There were 19 studies meeting inclusion criteria. Thirteen studies utilized [18F]FET, five utilized [11C]MET, and one utilized both. All studies used static AA PET parameters to evaluate TMZ treatment in glioma patients, with nine using dynamic tracer parameters in addition. Throughout these studies, AA PET demonstrated utility in TMZ treatment monitoring and predicting patient survival.

Functional connectivity of hippocampus in temporal lobe epilepsy depends on hippocampal dominance: a systematic review of the literature.

BACKGROUND: Lateralized alterations in hippocampal function in the resting-state have been demonstrated for patients with temporal lobe epilepsy (TLE). However, resting-state fMRI of the hippocampus has yet to be substantiated as an adjunct to standard pre-operative assessments of the seizure focus. OBJECTIVE: Here we report the results of a systematic review of resting-state fMRI studies investigating laterality of hippocampal network connectivity in TLE patients. METHODS: A search of the PubMed, SCOPUS, Web of Science, and Embase databases for full-length articles written in English was conducted through June 2020 using the following terms: 'resting state fMRI,' 'hippocampus,' 'epilepsy,' and 'laterality.' RESULTS: Our literature search yielded a total of 42 papers. After excluding studies that did not include patients with epilepsy, utilize resting-state fMRI, or explore the relationship between functional connectivity and disease lateralization, 20 publications were selected for inclusion. From these studies, a total of 528 patients, 258 with left TLE and 270 with right TLE, and 447 healthy controls were included. Of the 20 studies included, 18 found that patients with TLE demonstrated decreased hippocampal functional connectivity ipsilateral to the epileptogenic focus and 10 additionally reported increased hippocampal functional connectivity contralateral to the epileptogenic focus. Several studies demonstrated that the duration of disease was correlated with these changes in functional connectivity. This implies that a compensatory mechanism may be present in patients with treatment-refractory TLE. CONCLUSION: The consistency of this hippocampal connectivity pattern across multiple studies suggests resting-state fMRI may be useful as a non-invasive diagnostic tool for preoperative evaluation of TLE patients.

Patient Outcomes in Disorders of Consciousness Following Transcranial Magnetic Stimulation: A Systematic Review and Meta-Analysis of Individual Patient Data.

Background: There are few treatments with limited efficacy for patients with disorders of consciousness (DoC), such as minimally conscious and persistent vegetative state (MCS and PVS). Objective: In this meta-analysis of individual patient data (IPD), we examine studies utilizing transcranial magnetic stimulation (TMS) as a treatment in DoC to determine patient and protocol-specific factors associated with improved outcomes. Methods: We conducted a systematic review of PubMed, Ovid Medline, and Clinicaltrials.gov through April 2020 using the following terms: "minimally conscious state," or "persistent vegetative state," or "unresponsive wakefulness syndrome," or "disorders of consciousness" and "transcranial magnetic stimulation." Studies utilizing TMS as an intervention and reporting individual pre- and post-TMS Coma Recovery Scale-Revised (CRS-R) scores and subscores were included. Studies utilizing diagnostic TMS were excluded. We performed a meta-analysis at two time points to generate a pooled estimate for absolute change in CRS-R Index, and performed a second meta-analysis to determine the treatment effect of TMS using data from sham-controlled crossover studies. A linear regression model was also created using significant predictors of absolute CRS-R index change. Results: The search yielded 118 papers, of which 10 papers with 90 patients were included. Patients demonstrated a mean pooled absolute change in CRS-R Index of 2.74 (95% CI, 0.62-4.85) after one session of TMS and 5.88 (95% CI, 3.68-8.07) at last post-TMS CRS-R assessment. The standardized mean difference between real rTMS and sham was 2.82 (95% CI, -1.50 to 7.14), favoring rTMS. The linear regression model showed that patients had significantly greater CRS-R index changes if they were in MCS, had an etiology of stroke or intracranial hemorrhage, received 10 or more sessions of TMS, or if TMS was initiated within 3 months from injury. Conclusions: TMS may improve outcomes in MCS and PVS. Further evaluation with randomized, clinical trials is necessary to determine its efficacy in this patient population.

Anatomy and White Matter Connections of the Superior Parietal Lobule.

BACKGROUND: The superior parietal lobule (SPL) is involved in somatosensory and visuospatial integration with additional roles in attention, written language, and working memory. A detailed understanding of the exact location and nature of associated white matter tracts could improve surgical decisions and subsequent postoperative morbidity related to surgery in and around this gyrus. OBJECTIVE: To characterize the fiber tracts of the SPL based on relationships to other well-known neuroanatomic structures through diffusion spectrum imaging (DSI)-based fiber tracking validated by gross anatomical dissection as ground truth. METHODS: Neuroimaging data of 10 healthy, adult control subjects was obtained from a publicly accessible database published in Human Connectome Project for subsequent tractographic analyses. White matter tracts were mapped between both cerebral hemispheres, and a lateralization index was calculated based on resultant tract volumes. Post-mortem dissections of 10 cadavers identified the location of major tracts and validated our tractography results based on qualitative visual agreement. RESULTS: We identified 9 major connections of the SPL: U-fiber, superior longitudinal fasciculus, inferior longitudinal fasciculus, inferior fronto-occipital fasciculus, middle longitudinal fasciculus, extreme capsule, vertical occipital fasciculus, cingulum, and corpus callosum. There was no significant fiber lateralization detected. CONCLUSION: The SPL is an important region implicated in a variety of tasks involving visuomotor and visuospatial integration. Improved understanding of the fiber bundle anatomy elucidated in this study can provide invaluable information for surgical treatment decisions related to this region.

Optimal timing of post-operative enoxaparin after neurosurgery: A single institution experience.

PURPOSE: Venous thromboembolism (VTE) is a well-known problem in patients with intracranial tumors, especially high-grade gliomas. Optimal management of VTE complications is critical given that the development of deep vein thrombosis (DVT) and/or pulmonary embolism can exacerbate medical comorbidities and increase mortality. However, little is known about the optimum time to initiate post-operative anticoagulant prophylaxis. Therefore, there is a keen interest amongst neurosurgeons to develop evidence-based protocols to prevent VTE in post-operative brain tumor patients. METHODS: We retrospectively identified adult patients who underwent elective craniotomy for intracranial tumor resection between 2012 and 2017. Patients were categorized according to the time at which they began receiving prophylactic enoxaparin in the immediate post-operative period, within one day (POD 1), two days (POD 2), three days (POD 3), five days (POD 5), or seven days (POD 7). RESULTS: A total of 1087 patients had a craniotomy for intracranial tumor resection between 2012 and 2017. Multivariate binomial logistic regression analysis demonstrated that initiation of prophylactic enoxaparin within 72 h of surgery was protective against the likelihood of developing a lower extremity DVT (OR: 0.32; CI: 0.10-0.95; p = 0.049) while controlling for possible risk factors for DVTs identified on univariate analysis. Furthermore, complication rates between the anticoagulation and non-anticoagulation groups were not statistically significant. CONCLUSION: Initiating anticoagulant prophylaxis with subcutaneous enoxaparin sodium 40 mg once per day within 72 h of surgery can be done safely while reducing the risk of developing lower extremity DVT.

Co-existence of multiple sclerosis and germinoma in an adult male: Case report.

BACKGROUND: Concurrent diagnosis of multiple sclerosis (MS) and the central nervous system (CNS) germinoma is rare. The diagnostic criteria for MS rely primarily on clinical presentation, and CNS germinoma can present as an MS mimic. These factors contribute to the rarity of dual diagnosis. CASE DESCRIPTION: A 28-year-old man presented initially with bilateral optic neuritis, manifesting as persistently worsening vision for 2 years, and demyelinating plaques identified within the corpus callosum on magnetic resonance imaging. Initial work-up, in addition to clinical presentation, led to diagnosis of MS. Three months following the diagnosis of MS, the patient then presented with obstructive hydrocephalus due to a newly diagnosed intraventricular mass. The patient underwent an endoscopic third ventriculostomy and biopsy which confirmed diagnosis of CNS germinoma. CONCLUSION: To the best of our knowledge, dual presentation of both MS and CNS germinoma has never been reported in the literature. The clinical presentation of bilateral optic neuritis (persisting for roughly 2 years before initial MS diagnosis), demyelinating plaques, and intrathecal oligoclonal bands before the development of an intraventricular mass indicates that both MS and CNS germinoma presented simultaneously in this patient. The treatment plan for this patient included carboplatin + etoposide, followed by adjuvant radiation and subsequent IVIG therapy.

Cerebral venous thrombosis of the sphenoparietal sinus: A case report.

BACKGROUND: Cerebral venous thrombosis (CVT) is a rare cause of stroke that preferentially affects reproductive aged females and patients with hereditary or acquired thrombotic risk factors. The superior sagittal sinus and transverse sinus are the two most common sites for thrombus formation. CASE DESCRIPTION: We report a case of CVT arising in a very rare location, the sphenoparietal sinus. A 32-year-old woman with a history of factor V Leiden mutation and multiple prior episodes of venous thromboembolism presented with a new-onset seizure, headache, and emesis. CT angiography ultimately revealed thrombosis of the left sphenoparietal sinus. The patient received anticoagulation with apixaban with resolution of symptoms and without complications. CONCLUSION: This case serves as an uncommon example of sphenoparietal sinus thrombosis managed with novel oral anticoagulant treatment.

Anatomy and White Matter Connections of the Lingual Gyrus and Cuneus.

BACKGROUND: The medial occipital lobe, composed of the lingual gyrus and cuneus, is necessary for both basic and higher level visual processing. It is also known to facilitate cross-modal, nonvisual functions, such as linguistic processing and verbal memory, after the loss of the visual senses. A detailed cortical model elucidating the white matter connectivity associated with this area could improve our understanding of the interacting brain networks that underlie complex human processes and postoperative outcomes related to vision and language. METHODS: Generalized q-sampling imaging tractography, validated by gross anatomic dissection for qualitative visual agreement, was performed on 10 healthy adult controls obtained from the Human Connectome Project. RESULTS: Major white matter connections were identified by tractography and validated by gross dissection, which connected the medial occipital lobe with itself and the adjacent cortices, especially the temporal lobe. The short- and long-range connections identified consisted mainly of U-shaped association fibers, intracuneal fibers, and inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, middle longitudinal fasciculus, and lingual-fusiform connections. CONCLUSIONS: The medial occipital lobe is an extremely interconnected system, supporting its ability to perform coordinated basic visual processing, but also serves as a center for many long-range association fibers, supporting its importance in nonvisual functions, such as language and memory. The presented data represent clinically actionable anatomic information that can be used in multimodal navigation of white matter lesions in the medial occipital lobe to prevent neurologic deficits and improve patients' quality of life after cerebral surgery.

Percutaneous Thoracic Spinal Cord Stimulator Placement.

Spinal cord stimulation is a safe, effective, and reversible method for the management of chronic neuropathic pain. Spinal cord stimulation was found to be superior to traditional conservative management in recent clinical trials. The superiority of this therapeutic strategy is in part due to the many benefits, such as decreased use of prescription pain medications, cost-effectiveness, and improvement in patient quality of life. With appropriate patient consent for photography during the operation per hospital policy, the technical description for percutaneous placement of a spinal cord stimulator was documented at the authors home institution. The percutaneous technique allows for decreased operative times and thus reduced anesthesia, as well as decreased post-operative pain due to less tissue and muscle dissection. Additionally, the percutaneous leads have a smaller footprint in the epidural space, allowing more patients with mild spinal canal stenosis to receive this therapeutic device, which generally precludes paddle placement. These features make the percutaneous method an appealing alternative to the traditional laminotomy technique. The traditional laminotomy approach for paddle lead placement has been well described in the literature. However, detailed and indexed techniques of the percutaneous alternative are lacking. This technical description provides the first, easily accessible technical guide for the percutaneous placement of thoracic spinal cord stimulators. The operative technique was documented with images and detailed descriptions at the authors home institution.

Anatomy and White Matter Connections of the Middle Frontal Gyrus.

BACKGROUND: The middle frontal gyrus (MFG) is involved in attention, working memory, and language-related processing. A detailed understanding of the subcortical white matter tracts connected within the MFG can facilitate improved navigation of white matter lesions in and around this gyrus and explain the postoperative morbidity after surgery. We aimed to characterize the fiber tracts within the MFG according to their connection to neuroanatomic structures through the use of diffusion spectrum imaging-based fiber tractography and validate the findings by gross anatomic dissection for qualitative visual agreement. METHODS: Tractography analysis was completed using diffusion imaging data from 10 healthy, adult subjects enrolled in the Human Connectome Project. We assessed the MFG as a whole component according to its fiber connectivity with other neural regions. Mapping was completed on all tracts within both hemispheres, with the resultant tract volumes used to calculate a lateralization index. A modified Klingler technique was used on 10 postmortem dissections to demonstrate the location and orientation of the major tracts. RESULTS: Two major connections of the MFG were identified: the superior longitudinal fasciculus, which connects the MFG to parts of the inferior parietal lobule, posterior temporal lobe, and lateral occipital cortex; and the inferior fronto-occipital fasciculus, which connected the MFG to the lingual gyrus and cuneus. Intra- and intergyral short association, U-shaped fibers were also identified. CONCLUSIONS: Subcortical white matter pathways integrated within the MFG include the superior longitudinal fasciculus and inferior fronto-occipital fasciculus. The MFG is implicated in a variety of tasks involving attention and memory, making it an important cortical region. The postoperative neurologic outcomes related to surgery in and around the MFG could be clarified in the context of the anatomy of the fiber bundles highlighted in the present study.