Journal of neurosurgery
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Journal of neurosurgery · Sep 2018
Quantitative assessment of changes in hemodynamics of the internal carotid artery after bypass surgery for moyamoya disease.
OBJECTIVE Although intracranial vessel remodeling has been observed in moyamoya disease, concerns remain regarding the effect of bypass surgery on hemodynamic changes within the internal carotid artery (ICA). The authors aimed to quantify the surgical effect of bypass surgery on bilateral ICAs in moyamoya disease and to estimate pressure drop (PD) along the length of the ICA to predict surgical outcomes. METHODS Records of patients who underwent bypass surgery for treatment of moyamoya disease and in whom flow rates were obtained pre- and postsurgery by quantitative MR angiography were retrospectively reviewed. ⋯ Regression tests revealed that a greater postoperative decrease in PD corresponded to shrinking of ICAs (R2 = 0.22, p = 0.02). CONCLUSIONS PD may be used as a reliable biomechanical indicator for the assessment of surgical treatment outcomes. The vessel remodeling characteristics of contralateral ICA were related to CoW configurations.
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Journal of neurosurgery · Sep 2018
Perfusion-based human cadaveric specimen as a simulation training model in repairing cerebrospinal fluid leaks during endoscopic endonasal skull base surgery.
OBJECTIVE Competency in endoscopic endonasal approaches (EEAs) to repair high-flow cerebrospinal fluid (CSF) leaks is an essential component of the neurosurgical training process. The objective of this study was to demonstrate the feasibility of a simulation model for EEA repair of anterior skull base CSF leaks. METHODS Human cadaveric specimens were utilized with a perfusion system to simulate a high-flow CSF leak. ⋯ Residents gained new knowledge and a realistic simulation experience by rehearsing the psychomotor skills and techniques required to repair a CSF leak with fat and fascial grafts, as well as to prepare and rotate vascularized nasoseptal flaps. All trainees reported feeling safer with the procedure in a clinical setting and higher average posttraining confidence scores (pretraining 2.22 ± 0.83, posttraining 4.22 ± 0.44, p < 0.001). CONCLUSIONS Perfusion-based human cadaveric models can be utilized as a simulation training model for repairing CSF leaks during EEA.
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Journal of neurosurgery · Sep 2018
Machine learning applied to neuroimaging for diagnosis of adult classic Chiari malformation: role of the basion as a key morphometric indicator.
OBJECTIVE The current diagnostic criterion for Chiari malformation Type I (CM-I), based on tonsillar herniation (TH), includes a diversity of patients with amygdalar descent that may be caused by a variety of factors. In contrast, patients presenting with an overcrowded posterior cranial fossa, a key characteristic of the disease, may remain misdiagnosed if they have little or no TH. The objective of the present study was to use machine-learning classification methods to identify morphometric measures that help discern patients with classic CM-I to improve diagnosis and treatment and provide insight into the etiology of the disease. ⋯ CONCLUSIONS Tonsillar herniation as a unique criterion is insufficient for radiographic diagnosis of CM-I, which can be improved by considering the basion position. The position of the basion was altered in different entities of CM, including classic CM-I, classic CM-I with moderate TH, and CM-1.5. The authors propose a predictive model based on 3 parameters, all related to the basion location, to discern classic CM-I with 90% accuracy and suggest considering the anterior alterations in the evaluation of surgical procedures and outcomes.
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Journal of neurosurgery · Sep 2018
Microsurgical anatomy and approaches around the lateral recess with special reference to entry into the pons.
OBJECTIVE The lateral recess is a unique structure communicating between the ventricle and cistern, which is exposed when treating lesions involving the fourth ventricle and the brainstem with surgical approaches such as the transcerebellomedullary fissure approach. In this study, the authors examined the microsurgical anatomy around the lateral recess, including the fiber tracts, and analyzed their findings with respect to surgical exposure of the lateral recess and entry into the lower pons. METHODS Ten cadaveric heads were examined with microsurgical techniques, and 2 heads were examined with fiber dissection to clarify the anatomy between the lateral recess and adjacent structures. ⋯ The floccular peduncle ran rostral to the lateral recess, and this region was considered to be a potential safe entry zone to the lower pons. By appropriately selecting either route, medial-to-lateral or lateral-to-medial entry axis is possible, and combining both routes provided wide exposure of the lower pons around the lateral recess. CONCLUSIONS The medial and lateral routes of the transcerebellomedullary fissure approach provided wide exposure of the lateral recess, and incision around the floccular peduncle is a potential new safe entry zone to the lower pons.
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OBJECTIVE The purpose of this study was to describe in detail the cortical and subcortical anatomy of the central core of the brain, defining its limits, with particular attention to the topography and relationships of the thalamus, basal ganglia, and related white matter pathways and vessels. METHODS The authors studied 19 cerebral hemispheres. The vascular systems of all of the specimens were injected with colored silicone, and the specimens were then frozen for at least 1 month to facilitate identification of individual fiber tracts. ⋯ The functional importance of each structure is highlighted, and surgical approaches are suggested for each quadrant of the central core. CONCLUSIONS As a general rule, the internal capsule and its vascularization should be seen as a parasagittal barrier with great functional importance. This is of particular importance in choosing surgical approaches within this region.