World Neurosurg
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Face recognition is a complex function sustained by a distributed large-scale neural network, with a core system involving the ventral occipitotemporal cortex, the inferior longitudinal fasciculus (ILF), and the splenial commissural fibers. This circuit seems to be bilaterally organized, but with a right hemispheric dominance. According to this anatomic functional model, prosopagnosia is usually, but not exclusively, generated by a damage of the right part of this brain network. ⋯ The authors investigate the possible causes resulting in this prosopagnosia. Specifically, they suggest a decompensation within a reorganized neural network after the first operation, because of a disconnection syndrome induced by a bilateral surgical damage of the ventral occipitotemporal structural connectivity. These original data can be useful for neurosurgeons, especially when achieving resection for multicentric tumors involving both ventral streams, to inform patients before surgery about the possible risk of face recognition deficit, and to adapt the cognitive tasks intraoperatively during awake procedure.
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Spontaneous meningoencephaloceles of the lateral sphenoid sinus are rare entities, and their peculiar location represents a surgical challenge due to the importance of a wide exposure and skull base reconstruction. They are thought to arise from the congenital base defect of the lateral sphenoid or in some cases have been postulated to represent a rare manifestation of altered cerebrospinal fluid (CSF) dynamics. We report the first case in the literature of a Chiari malformation type I (CMI) and a lateral sphenoid encephalocele, revising the theoretic etiology and surgical technique of endoscopic repair. ⋯ The association of spontaneous lateral sphenoid encephaloceles with CMI is distinctly unusual. Predisposing factors and disruption of CSF dynamics may play a major role in the development of these rare complications in patients with CMI. Because of their distinct location, transethmoid or transpterygoid endoscopic approaches represent an excellent surgical technique to treat these lesions thanks to their wide and direct visualization of the entire skull base defect following the encephalocele excision, allowing an adequate multilayer repair and lateral sphenoid recess occlusion.
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Positional plagiocephaly is the most common cause of cranial asymmetry. The underlying cause of Chiari-1 malformation has many possible theories, and anecdotally some pediatric neurosurgeons have had experience of severe cases of positional brachycephaly with Chiari-1. However, to date, there have been no published cases linking nonsynostotic plagiocephaly with Chiari-1 malformation. ⋯ Chronic hindbrain herniation is well reported in cases of craniosynostosis, but to our knowledge this is the first published case associated with nonsynostotic deformational plagiocephaly. We hypothesize that severe posterior plagiocephaly can cause disproportion of the posterior fossa: hindbrain volume ratio and acquired chronic cerebellar herniation. Nevertheless, positional plagiocephaly and Chiari-1 are common entities, and it is possible that the dual diagnoses were coincidental in this case. This report serves to raise awareness of a putative causal relationship between positional plagiocephaly, reduced posterior fossa volume, and hindbrain herniation.
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Case Reports
Unique venous drainage of a sphenoid wing dural arteriovenous fistula with ocular symptoms.
Dural arteriovenous fistulas (DAVFs) presenting with ocular symptoms, such as exophthalmos and chemosis, are commonly situated in the cavernous sinus (CS). DAVFs at the sphenoid wing with a drainage route into the superior orbital vein (SOV) should be considered as one of the differential diagnoses of ocular symptoms. ⋯ After embolization, the ocular symptoms resolved, and the patient was discharged without neurologic deficit. Herein, we discuss the developmental mechanism of the unique drainage pattern, including the clinical symptoms and anatomic features of greater sphenoid wing DAVFs.
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Regional neurovascular structures must be avoided during invasive spine hardware placement. During C1 lateral mass screw placement, the C2 nerve root is put in harm's way. Therefore the current anatomic study was performed to identify techniques that might avoid such neural injury. ⋯ On the basis of our cadaveric study, the C2 nerve root can be detethered enough at the level of the posterior lateral mass of C1 to avoid its injury during screw placement into this area.