Showing papers by "Michael E. Sughrue published in 2019"

Anatomy and white matter connections of the inferior frontal gyrus

Abstract: The inferior frontal gyrus (IFG) is involved in the evaluation of linguistic, interoceptive, and emotional information. A detailed understanding of its subcortical white matter anatomy could improve postoperative morbidity related to surgery in and around this gyrus. Through GQI-based fiber tracking validated by gross anatomical dissection as ground truth, we characterized the fiber tracts of the IFG based on relationships to other well-known neuroanatomic structures. Diffusion imaging from the Human Connectome Project for 10 healthy adult controls was used for fiber tracking analysis. We evaluated the IFG as a whole based on its connectivity with other regions. All tracts were mapped in both hemispheres, and a lateralization index was calculated based on resultant tract volumes. Ten cadaveric dissections were then performed using a modified Klingler technique to demonstrate the location of major tracts. We identified four major connections of the IFG: a white matter bundle corresponding the frontal aslant tract connecting to the superior frontal gyrus; the superior longitudinal fasciculus connecting to the inferior parietal lobule, lateral occipital area, posterior temporal areas, and the temporal pole; the inferior fronto-occipital fasciculus connecting to the cuneus and lingual gyrus; and the uncinate fasciculus connecting to the temporal pole. A callosal fiber bundle connecting the inferior frontal gyri bilaterally was also identified. The IFG is an important region implicated in a variety of tasks including language processing, speech production, motor control, interoceptive awareness, and semantic processing. Postsurgical outcomes related to this region may be better understood in the context of the fiber-bundle anatomy highlighted in this study. Clin. Anat. 32:546-556, 2019. © 2019 Wiley Periodicals, Inc.

Parcellation-based tractographic modeling of the dorsal attention network.

Abstract: INTRODUCTION The dorsal attention network (DAN) is an important mediator of goal-directed attentional processing. Multiple cortical areas, such as the frontal eye fields, intraparietal sulcus, superior parietal lobule, and visual cortex, have been linked in this processing. However, knowledge of network connectivity has been devoid of structural specificity. METHODS Using attention-related task-based fMRI studies, an anatomic likelihood estimation (ALE) of the DAN was generated. Regions of interest corresponding to the cortical parcellation scheme previously published under the Human Connectome Project were co-registered onto the ALE in MNI coordinate space and visually assessed for inclusion in the network. DSI-based fiber tractography was performed to determine the structural connections between relevant cortical areas comprising the network. RESULTS Twelve cortical regions were found to be part of the DAN: 6a, 7AM, 7PC, AIP, FEF, LIPd, LIPv, MST, MT, PH, V4t, VIP. All regions demonstrated consistent u-shaped interconnections between adjacent parcellations. The superior longitudinal fasciculus connects the frontal, parietal, and occipital areas of the network. CONCLUSIONS We present a tractographic model of the DAN. This model comprises parcellations within the frontal, parietal, and occipital cortices principally linked through the superior longitudinal fasciculus. Future studies may refine this model with the ultimate goal of clinical application.

Bilateral Carotid-cavernous Fistulas Treated with Partial Embolization and Radiosurgery

Abstract: Bilateral carotid-cavernous fistulas (CCFs) are rare. In this paper, we report the case of an 88-year-old woman who presented with a two-month history of worsening visual symptoms and was subsequently found to have bilateral Barrow grade D CCFs. Cannulation and complete embolization of the offending vessels during angiography proved unsuccessful, and so the patient underwent adjuvant radiosurgery as salvage therapy with a good clinical outcome. This case adds to the limited but growing literature on the multi-modal management of CCFs.

Butterfly glioma resection: Surgery around the initiation axis

Abstract: For a long time, the frontal lobe has been a synonym for “safe” in neurosurgery. In most surgical management schemes, the “eloquent areas” are principally listed the motor strip, the language areas, and perhaps the supplementary motor area. The term “eloquent” is principally the term used in the neurosurgical community which refers to areas of the brain which when transgressed cause a visible observable deficit, usually one that can easily be described by a nonexpert, like the inability to talk or move one’s arm, for example. In this paradigm, our only mandate is to avoid destroying these areas, and we theoretically have carte blanche to do whatever with the rest of the largest lobe in the human brain.

Pharmacotherapeutic options for atypical meningiomas.

Abstract: Introduction: Atypical meningiomas are aggressive tumors associated with high rates of recurrence and mortality. Current therapy is surgical resection followed by radiotherapy which has reasonable success rates. However, there are cases where surgical resection is not possible, and radiotherapy is not advisable. Areas covered: In this short review, the authors have searched the current literature for explorations of adjuvant treatments such as chemotherapy and pharmaceutical agents. Most current chemotherapeutic agents have been unsuccessful in producing radiographic reduction or disease stabilization, although drugs like somatostatin analogs and plant-derived chemotherapeutics have shown some promise. The authors note that most of the studies in this field have been case series with a few randomized trials present. This makes it hard to ascertain the effectiveness of the drugs and so further research is required in the field. Expert opinion: Finding pharmacotherapies to combat atypical meningiomas needs Big data genomic analysis. This will assist in generating drug candidates and a multidrug approach to therapy that will exploit several of the pathological pathways of atypical meningiomas. Using multidrug therapy that affects several pathways also addresses the issue of meningioma heterogeneity and adaptability.

Surg-05. laser interstitial thermal therapy for melanoma brain metastasis: a case series

Abstract: Abstract Stereotactic radiosurgery (SRS) and whole brain radiation therapy (WBRT) have been established as non-invasive treatment modalities for intracranial metastasis from malignant melanoma, with SRS emerging as a safe and effective stand along therapy. However, either due to tumor regrowth or radiation necrosis, these radiation modalities can fail. MR-guided laser interstitial thermal therapy (LITT) has emerged as an option for these tumors. Clinical data for five patients at our institution was retrospectively reviewed. These were all the patients that had undergone LITT for intracranial metastatic melanoma after prior treatment failure that included a radiation modality. Demographics, prior treatments, surgical data, perioperative complications, adjuvant treatments, and follow imaging data were gathered. Of the five patients, one patient had received WBRT, three patients had received prior SRS to the area that underwent LITT, and one patient had a prior craniotomy with adjuvant SRS. Two of the tumors were located in the premotor area (frontal lobe), two tumors were located in the motor strip, and one tumor was located in the cerebellum. The average tumor volume was 4.32 cc (range 1.86 - 7.84 cc). Median time of hospital stay was 2 days (with a 2.6 day average). No perioperative complications were encountered. Three of the patients had received adjuvant therapy at our institution; these patients were not delayed in receiving adjuvant therapy. Of these three patients, only one patient had a BRAF mutation detected. Four patients received follow up imaging at our institution, with no patients demonstrating tumor regrowth in the site of LITT. Regrowth of intracranial metastasis of malignant melanoma is a known possibility of traditional radiation therapies. LITT should be considered as a safe, effective option for those that fail these traditional therapies, especially those located in areas difficult to access. The low complication rate allows patients to restart adjuvant therapies.

Essentials to planning a brainstem case

Abstract: The purpose of this chapter is to discuss our thought process when evaluating a patient with a newly diagnosed brainstem tumor. The best predictor of surgical outcome is the accuracy of the preoperative plan (i.e., poor planning will lead to poor outcomes). The differential diagnosis of a brainstem lesion is broad and carries both benign and malignant entities. We discuss how the clinical presentation and physical examination findings may give clues to narrow the differential diagnosis. Overlooked inconsistencies between physical examination and imaging findings can take you down the wrong path. We will discuss the characteristic radiographic findings of the most common tumors as well as some less commonly encountered lesions that should be kept in the differential. While we are not radiologists, a large effort has been made to provide our process of evaluating imaging of these lesions. When a surgeon is presented with a brainstem lesion, it is easy to jump to conclusions as to the diagnosis. We would argue instead to not decide the pathology until a careful analysis is performed.