Publications by authors named "Etienne Lefevre"

Cranial dural arteriovenous fistulas (DAVFs) that display cortical venous drainage are at risk of hemorrhage, unlike spinal DAVFs, which seldom bleed. The underlying mechanism for this difference is poorly understood. We hypothesized that cerebral veins are more fragile than spinal veins due to differences in histologic compositions.

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Article Synopsis
  • This study evaluates the surgical outcomes of patients aged 80 and older who underwent surgery for large vestibular schwannomas (VS).
  • Thirteen patients were examined, with most experiencing good facial function post-surgery and a low rate of serious complications.
  • The findings suggest that older age should not automatically prevent patients from undergoing VS surgery, and that planned partial resection is a viable option for elderly patients.
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Traumatic intracranial aneurysm (TICA) is a rare and aggressive pathology that requires prompt treatment. Nevertheless, early vascular imaging following head trauma may yield falsely negative results, underscoring the importance of subsequent imaging within the first week to detect delayed TICAs. This study aims to report our experience with delayed TICAs and highlight the clinical importance of repeated angiographic screening for delayed TICAs.

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Context: Entrapment of the temporal horn (TH) is rare condition that can lead to increased intracranial pressure, but there is no consensus on a standard treatment. The aim of this study was to conduct a systematic literature review of the reported cases of TH entrapment and describe our operative technique for endoscopic fenestrations of the lateral ventricle into the basal cisterns.

Methods: We searched the databases Pubmed and Google scholar to find all studies reporting cases of entrapped TH and the subsequent treatment.

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The upper end of the central canal of the human spinal cord has been repeatedly implicated in the pathogenesis of various diseases, yet its precise normal position in the medulla oblongata and upper cervical spinal cord remains unclear. The purpose of this study is to describe the anatomy of the upper end of the central canal with quantitative measurements and a three-dimensional (3D) model. Seven formalin-embalmed human brainstems were included, and the central canal was identified in serial axial histological sections using epithelial membrane antigen antibody staining.

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Article Synopsis
  • Cavernous sinus invasion by pituitary adenomas makes complete surgical removal difficult, affects recovery outcomes, and raises the chance of tumor recurrence, highlighting the need for accurate preoperative MRIs and intraoperative evaluations.
  • * Research into the genetic factors involved in the invasiveness of these tumors is still limited, but some genes have been linked to their aggressive nature, albeit with challenges in comparison studies.
  • * New surgical techniques, including extended endoscopic procedures and the use of medications like somatostatin agonists, show promise in managing these invasive adenomas, but further understanding of their molecular behavior is crucial for better treatment options.
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The existence, composition, and continuity of the medial wall of the cavernous sinus (MWCS) have been extensively studied and debated. However, the precise nature of this membrane remains unknown. Understanding the anatomical characteristics of the MWCS is crucial, notably in relation to pituitary adenomas, which often invade the cavernous sinus.

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The diagnosis of large vestibular schwannomas (VS) with retained useful hearing has become increasingly common. Preservation of facial nerve (FN) function has improved using intraoperative EMG monitoring, hearing preservation remains challenging, with the recent use of cochlear nerve action potential (CNAP) monitoring. This prospective longitudinal series of VS with useful hearing operated on using a retrosigmoid approach included 37 patients with a mean largest extrameatal VS.

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Study Objectives: To evaluate sleep, sleepiness, and excessive need for sleep in patients with craniopharyngioma (a suprasellar tumor which can affect sleep-wake systems).

Methods: A retrospective study of all adult patients living with craniopharyngioma referred to the sleep clinic, who received a sleep interview, nocturnal polysomnography, multiple sleep latency tests (MSLT), and 18-h bed rest polysomnography. Their sleep measurements were compared with those of age- and sex-matched healthy controls.

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Purpose: Clinical and radiological assessment of endoscopic third ventriculocisternostomy (ETV) patency can be challenging in children. The objective of our study was thus to test the accuracy and interrater reliability of 3D fast-spin echo (FSE) T2-weighted sequences to assess the patency of ETV.

Methods: We included all the consecutive children who underwent surgery for ETV over a two-year period and selected the children who presented ETV dysfunction and matched them with children without dysfunction.

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Purpose: Ventricular drainage remains a usual but challenging procedure for neurosurgical trainees. The objective of the study was to describe reliable skin landmarks for ideal entry points (IEPs) to catheterize brain ventricles via frontal and parieto-occipital approaches.

Methods: We included 30 subjects who underwent brain MRI and simulated the ideal catheterization trajectories of lateral ventricles using anterior and posterior approaches and localized skin surface IEPs.

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Article Synopsis
  • Acquiring skills in microsurgical anastomosis is difficult for trainees, but laboratory simulation models help them practice these techniques before real surgeries.
  • A study analyzed 44 trainees over 7 months, focusing on end-to-end and end-to-side anastomoses on rats, revealing a 41% patency rate and a decrease in dissection and clamping times as training progressed.
  • Key findings highlighted that the duration of training and technical mistakes significantly impacted the learning curve, suggesting further research is needed on factors affecting long-term skill retention in microsurgery.
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Purpose: Spetzler-Martin grade (SMG) I-II (low-grade) brain arteriovenous malformations (BAVMs) are often considered safe for microsurgical resection; however, the role of endovascular treatment (EVT) remains to be clarified in this indication, especially for unruptured BAVMs. The purpose of our study was to assess the safety and effectiveness of endovascular treatment as the first-line treatment for low-grade BAVMs.

Methods: From our local database, we retrospectively retrieved patients with low-grade BAVMs, either ruptured or unruptured, treated by embolization as first-line treatment in our department between January 2005 and January 2020.

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Purpose: In a previous cadaveric work, we identified and described useful and reproducible surface skin landmarks to lateral sulcus, central sulcus and preoccipital notch. Potential limitations of this cadaveric study have been raised. Thus, the objective of this study was to confirm radiologically the accuracy of these previously described surface skin landmarks on brain magnetic resonance imaging (MRI) of healthy subjects.

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Anterior fossa dural arteriovenous fistulas (AF-DAVF) usually display a cortical venous drainage and are therefore at risk for rupture. Microsurgery is traditionally considered in many centers as the first-line treatment since endovascular treatment (EVT) entails a lower cure rate and significant ophthalmic risks. The anterior interhemispheric approach (AIA), originally described by Mayfrank in 1996, seems to offer the effectiveness of microsurgery while limiting the risks related to subfrontal craniotomy.

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Purpose: Neuronavigation is used in neurosurgical practice to locate the cortical structures. If this tool is unavailable, basic anatomical knowledge should be used. Craniometry has been rarely detailed in recent literature, systematically using bony landmarks.

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Background: Predictors of visual outcomes after optic nerve decompression are controversial.

Objective: To identify the predictors of poor visual outcomes after surgery of meningiomas responsible of a compressive optic neuropathy.

Methods: We focused on paraoptic meningiomas (POMs), which gathered tuberculum sellae meningiomas (TSMs) and anterior clinoid meningiomas (ACMs) responsible for visual impairment or threatening visual function, that underwent surgery at our institution between January 2009 and December 2015 and analyzed the clinical and radiological findings of our patients.

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Background: The precise understanding of the angioarchitecture of spinal vascular malformations (SVMs) is often difficult to reach with conventional digital subtraction angiography (DSA). The purpose of our study was to evaluate the potential of four-dimensional DSA (4D-DSA) (Siemens Healthcare) in the exploration of SVMs.

Methods: We retrospectively studied all patients who underwent spinal DSA, including 4D-DSA acquisition, from July 2018 to June 2019 at a single institution.

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Background: Isolated bilateral hypoglossal palsy is a rare condition that has never been described after surgery in the lower part of the fourth ventricle. In this article, we discuss various possible etiologies and relevant anatomy considerations of the rhomboid fossa.

Case Description: We describe a case of bilateral hypoglossal palsy with tongue ptosis following surgery of an ependymoma in the lower part of the fourth ventricle.

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Purpose: When dealing with paraclinoid carotid aneurysms, the distinction between intradural and extradural location is a major component for decision-making as only intradural aneurysms carry a risk of subarachnoid hemorrhage (SAH). The aim of this study was to test the accuracy and reliability of computed tomography (CT) bony landmarks for the distinction between intradural and extradural paraclinoid aneurysms.

Methods: All patients referred to this institution for a single paraclinoid aneurysm were retrospectively identified.

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Background: There is no consensus regarding the best treatment option for unruptured aneurysms of the posterior communicating artery (PCom) presenting with oculomotor nerve palsy (ONP). We aimed to assess predictors of ONP recovery in a multicenter series of consecutive patients.

Materials And Methods: A retrospective review of prospective databases in three tertiary neurosurgical centers was carried out, selecting patients with ONP caused by unruptured PCom aneurysms, treated by surgical clipping or embolization, between January 2006 and December 2013.

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Objective: Treatment of posterior fossa arteriovenous malformations (PFAVMs) remains controversial as it is always challenging and may lead to major complications. Nonetheless, these lesions are more likely to bleed and generate poorer outcomes than other brain AVMs. The aim of this study was to evaluate the effect of endovascular treatment on long-term outcomes and identify the patient subgroups that might benefit from endovascular treatment.

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Background: No link has been demonstrated between diffuse intrinsic pontine glioma and developmental venous anomaly in pediatric patients.

Objective: To determine the prevalence of developmental venous anomaly in a pediatric cohort of diffuse intrinsic pontine glioma.

Methods: We performed a retrospective cohort study (1998-2017) of consecutive pediatric patients harboring a diffuse intrinsic pontine glioma (experimental set, n = 162) or a craniopharyngioma (control set, n = 142) in a tertiary pediatric neurosurgical center.

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