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Objective: There is a body of evidence that supports the idea of a coordinated interplay between three large-scale cerebral networks, the default mode network (DMN), the control network (CTRL), and the salience network (SN). Interactions between these networks have been linked with the process of transitioning from internal to external mental states. Methods: Using meta-analytic software provided by BrainMap, we generated anatomic likelihood estimates (ALEs) of the DMN, SN, and CTRL networks. ALEs were displayed using Mango. Pre-constructed Region of Interests(ROIs) corresponding to the 180 cerebral parcellations published under the Human Connectome Project were used to identify the parcellations comprising each network. DSI-based fiber tracking was performed to establish the connectivity between parcellations of each network. Results: The DMN includes parcellations that localize to the posterior and anterior cingulate cortex and inferior parietal lobule. The CTRL network localizes to the dorsolateral prefrontal cortex and lateral parietal lobe. The SN localizes to the middle cingulate cortex and anterior insula. The SN also connects to SCEF, a parcellation in the supplementary motor area. Conclusion: The DMN is a well-known resting-state network that is anti-correlated with the CTRL network. The SN has been described as the switch between these two networks. The SN's connection to SCEF may explain how the brain prepares for proposed activity during such transfers. We propose models of three critical brain networks that play a role in the transition from internal to external mental states. Future studies will refine these models of the command-and-control axis for clinical application. [ABSTRACT FROM AUTHOR]

Objective: The Inferior Longitudinal Fasciculus (ILF) is one of the major white matter tract bundles connecting key cortical areas of the cerebrum. The location, functional connectivity, and structural connectivity of the cortical regions giving rise to the ILF have previously been described. Using these data we demonstrate the extent and anatomical boundaries of the ILF. Methods: We built an anatomic model of the ILF based on the parcellation scheme previously published under the Human Connectome Project. Through Diffusion Spectrum Imaging, we demonstrate the tractography of this fasciculus arising from its relevant cortical regions, and show a tract map summarizing those regions with white matter connections specific to the ILF. Results: The ILF extends from the ventral and lateral temporal cortices to parts of the occipital lobe. Seven parcellations of the temporal lobe and one from the posterior parietal lobe demonstrate structural connectivity in the distribution of the ILF. Most demonstrate fiber tracts via the ILF to early visual areas, V1-V4. Conclusion: The literature describes several critical functions to the ILF including visual processing, object recognition, reading disturbance, emotional processing, facial recognition, ventral semantic processing, visual hallucinations, and arithmetic. Precisely what cortical information is integrated and transferred from the occipital lobe to areas of the temporal and parietal lobes remains poorly understood. Our connection model of the ILF is one step forward towards elucidating these processes. We show the anatomic connections of the ILF and define the cortical regions from which the ILF arises. Future studies will refine this model for clinical application. [ABSTRACT FROM AUTHOR]

Background and Importance: The second stage of deep brain stimulation requires the placement of an implantable pulse generator (IPG). Although the current placement technique achieves acceptable outcomes, device erosion has been reported. We describe a simple surgical option aimed at increasing device longevity by placing the hardware under the superficial pectoralis fascia., Clinical Presentation: We describe and illustrate the technique of placing the IPG in the subfascial space in a patient undergoing deep brain stimulation. In addition, we provide pearls and pitfalls to be mindful of when implementing this method., Conclusion: In this technical report, we have outlined a simple alternative approach to the traditional subcutaneous IPG placement by placing the IPG under the superficial pectoralis fascia. This subfascial approach can potentially reduce complications and preserve device longevity., Competing Interests: The authors have no personal, financial, or institutional interest in any of the drugs, materials, or devices described in this article., (© The Author(s) 2023. Published by Wolters Kluwer Health, Inc. on behalf of Congress of Neurological Surgeons.)

Background: Laser interstitial thermal therapy (LITT) is being used for the treatment of recurrent glioblastoma multiforme (GBM). Lesions can be treated using 1 or multiple LITT fibers depending on the preference of surgeons. Usually, more fibers are needed for coverage of larger tumors., Objective: To investigate and analyze how tumor size affected the number of LITT fibers used., Methods: This is a retrospective review of patients undergoing treatment of recurrent GBM. Patients were treated with up to 4 LITT fibers for adequate tumor coverage. Patient demographics, tumor characteristics, length of stay, complications, and biopsy results were recorded., Results: A total of 43 cases were treated using LITT, and of these cases, 31 consisted of contiguous lesions. We used more fibers to treat larger tumor volumes. On average, for each 5 cc of tumor volume, a fiber was added for proper coverage (P = .554). Complications and length of stay were similar across the groups (P = .378, P = .941)., Conclusion: LITT can be used for the treatment of recurrent GBM. For each 5 cc of tumor volume, a LITT fiber can be added to the treatment plan., (Copyright © 2020 by the Congress of Neurological Surgeons.)

Background: Dural repair in areas with limited operative maneuverability has long been a challenge in skull base surgery. Without adequate dural closure, postoperative complications, including cerebrospinal fluid (CSF) leak and infection, can occur., Objective: To show a novel method by which nonpenetrating, nonmagnetic titanium microclips can be used to repair dural defects in areas with limited operative access along the skull base., Methods: We reviewed 53 consecutive surgical patients in whom a dural repair technique utilizing titanium microclips was performed from 2013 to 2016 at our institution. The repairs primarily involved difficult-to-reach dural defects in which primary suturing was difficult or impractical. A detailed surgical technique is described in 3 selected cases involving the anterior, middle, and posterior fossae, respectively. An additional 5 cases are provided in more limited detail to demonstrate clip artifact on postoperative imaging. Rates of postoperative CSF leak and other complications are reported., Results: The microclip technique was performed successfully in 53 patients. The most common pathology in this cohort was skull base meningioma (32/53). Additional surgical indications included traumatic dural lacerations (9/53), nonmeningioma tumors (8/53), and other pathologies (4/53). The clip artifact present on postoperative imaging was minor and did not interfere with imaging interpretation. CSF leak occurred postoperatively in 3 (6%) patients. No obvious complications attributable to microclip usage were encountered., Conclusion: In our experience, intracranial dural closure with nonpenetrating, nonmagnetic titanium microclips is a feasible adjunct to traditional methods of dural repair.

Background  The use of intrathecal antibiotic therapy for the treatment of ventriculitis and/or meningitis has demonstrated efficacy especially when sterilization of the cerebrospinal fluid is not possible with intravenous antibiotics alone. Case Description  We describe the successful treatment of Enterococcus faecalis ventriculitis utilizing intrathecal linezolid in a 32-year-old female patient with severe allergy to vancomycin, prohibitive bacterial susceptibilities, and failure of previous attempts to sterilize the cerebrospinal fluid despite multimodal treatment. Conclusion  Intrathecal linezolid is a useful treatment in the setting of multidrug-resistant bacterial ventriculitis. We present a useful dosing regimen for the administration of intrathecal linezolid.

Fractures of the anterior skull base may occur in gunshot victims and can result in traumatic cerebrospinal fluid (CSF) leak. Less commonly, CSF leaks occur days or even weeks after the trauma occurred. Here, we present the case of a 21-year-old man with a delayed-onset, traumatic CSF leak secondary to a missile injury that left a bullet fragment in the Rosenmuller fossa. The patient was treated successfully with endoscopic, endonasal extraction of the bullet, and repair with a nasal septal flap. Foreign bodies lodged in Rosenmuller fossa can be successfully treated with endoscopic skull base surgery.

Ventricular shunt failures and subsequent revisions are a significant source of patient morbidity. We conducted a review of pediatric patients undergoing placement or revision of ventricular shunts at our institution between January 2007 and December 2008. Patients were followed through to July 2014. Data collected included patient demographics, shunt history and indication for procedure, approach taken for shunt placement, and location of shunt tip in relation to the foramen of Monro. Univariate and multivariate analyses were conducted to identify factors associated with proximal failure. A total of 87 procedures were identified in 40 patients, consisting of 23 initial placements and 64 revisions. Thirty-nine proximal catheter malfunctions were identified. Indications for shunt placement included Chiari II malformation (33%) and intraventricular hemorrhage (33%). Mean follow-up period was 5.5 years. Median time to shunt failure was 1.57 years. In the multivariate model, younger age at placement was associated with decreased time to proximal failure (hazard ratio [HR]=0.80 per increasing year of age, 95% confidence interval [CI] 0.64-0.98). Both anterior approach (HR=0.39, 95% CI 0.23-0.67) and farther distance to foramen of Monro (HR=0.02 per increasing 10mm, 95% CI 0.00-0.22) were associated with increased time to proximal failure when the catheter tip was located within the contralateral lateral ventricle. Optimizing outcomes in patients with shunt-dependent hydrocephalus continues to be a challenge. Despite unsatisfactory outcomes, particularly in the pediatric population, few conclusions can be drawn from studies assessing operative variables., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Gangliogliomas are rare tumors that comprise up to 40% of lesional epilepsy. Seizure control represents an important quality-of-life determinant in patients with these tumors. Here we present results of a literature review addressing rates of seizure freedom in in patients with gangliogliomas. Across studies, seizure freedom occurred in 63%-100% of patients. Many studies included follow-up times of greater than 5 years, suggesting that the responses are durable. We discuss potential prognostic factors associated with seizure freedom, including the duration of epilepsy, patient age, frequency and semiology of seizures, tumor location, extent of surgical resection, and operative strategy, including surgical approach and use of invasive monitoring. Although significant differences in study populations and treatments preclude meta-analysis, we discuss prognostic factors identified in individual studies. Increased extent of resection, lesser duration of epilepsy, and younger age at surgery have been associated with increased seizure freedom rates in at least 2 studies each. Although all studies were retrospective in nature and are consequently limited by the weaknesses inherent to such investigations, the literature suggests that surgery is able to relieve most ganglioglioma patients--regardless of patient demographics, tumor characteristics, and operative variables--of seizures., (Copyright © 2015 Elsevier Inc. All rights reserved.)