Publications by authors named "Timothée Jacquesson"

30 Publications

  • Page 1 of 1

Autophagic Markers in Chordomas: Immunohistochemical Analysis and Comparison with the Immune Microenvironment of Chordoma Tissues.

Cancers (Basel) 2021 Apr 30;13(9). Epub 2021 Apr 30.

Pathology Department, University Hospital of Saint-Etienne, 42055 Saint-Etienne, France.

Chordomas are notably resistant to chemotherapy. One of the cytoprotective mechanisms implicated in chemoresistance is autophagy. There are indirect data that autophagy could be implicated in chordomas, but its presence has not been studied in chordoma tissues. Sixty-one (61) chordomas were immunohistochemically studied for autophagic markers and their expression was compared with the expression in notochords, clinicopathological data, as well as the tumor immune microenvironment. All chordomas strongly and diffusely expressed cytoplasmic p62 (sequestosome 1, SQSTM1/p62), whereas 16 (26.2%) tumors also showed nuclear p62 expression. LC3B (Microtubule-associated protein 1A/1B-light chain 3B) tumor cell expression was found in 44 (72.1%) tumors. Autophagy-related 16‑like 1 (ATG16L1) was also expressed by most tumors. All tumors expressed mannose-6-phosphate/insulin-like growth factor 2 receptor (M6PR/IGF2R). LC3B tumor cell expression was negatively associated with tumor size, while no other parameters, such as age, sex, localization, or survival, were associated with the immunohistochemical factors studied. LC3B immune cell expression showed a significant positive association with programmed death-ligand 1 (PD-L1)+ immune cells and with a higher vascular density. ATG16L1 expression was also positively associated with higher vascular density. Notochords ( = 5) showed different immunostaining with a very weak LC3B and M6PR expression, and no p62 expression. In contrast to normal notochords, autophagic factors such as LC3B and ATG16L1 are often present in chordomas, associated with a strong and diffuse expression of p62, suggesting a blocked autophagic flow. Furthermore, PD-L1+ immune cells also express LC3B, suggesting the need for further investigations between autophagy and the immune microenvironment.
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http://dx.doi.org/10.3390/cancers13092169DOI Listing
April 2021

WIKIBrainStem: An online atlas to manually segment the human brainstem at the mesoscopic scale from ultrahigh field MRI.

Neuroimage 2021 Apr 18;236:118080. Epub 2021 Apr 18.

UMR 1253, iBrain, Université de Tours, Inserm, Tours, France; CHRU de Tours, Tours, France. Electronic address:

The brainstem is one of the most densely packed areas of the central nervous system in terms of gray, but also white, matter structures and, therefore, is a highly functional hub. It has mainly been studied by the means of histological techniques, which requires several hundreds of slices with a loss of the 3D coherence of the whole specimen. Access to the inner structure of the brainstem is possible using Magnetic Resonance Imaging (MRI), but this method has a limited spatial resolution and contrast in vivo. Here, we scanned an ex vivo specimen using an ultra-high field (11.7T) preclinical MRI scanner providing data at a mesoscopic scale for anatomical T2-weighted (100 µm and 185 µm isotropic) and diffusion-weighted imaging (300 µm isotropic). We then proposed a hierarchical segmentation of the inner gray matter of the brainstem and defined a set of rules for each segmented anatomical class. These rules were gathered in a freely accessible web-based application, WIKIBrainStem (https://fibratlas.univ-tours.fr/brainstems/index.html), for 99 structures, from which 13 were subdivided into 29 substructures. This segmentation is, to date, the most detailed one developed from ex vivo MRI of the brainstem. This should be regarded as a tool that will be complemented by future results of alternative methods, such as Optical Coherence Tomography, Polarized Light Imaging or histology… This is a mandatory step prior to segmenting multiple specimens, which will be used to create a probabilistic automated segmentation method of ex vivo, but also in vivo, brainstem and may be used for targeting anatomical structures of interest in managing some degenerative or psychiatric disorders.
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http://dx.doi.org/10.1016/j.neuroimage.2021.118080DOI Listing
April 2021

Overcoming challenges of the human spinal cord tractography for routine clinical use: a review.

Neuroradiology 2020 Sep 4;62(9):1079-1094. Epub 2020 May 4.

Laboratoire CREATIS, CNRS UMR5220, Inserm U1206, INSA-Lyon, Université de Lyon I, Lyon, France.

The spinal cord (SC) is a dense network of billions of fibers in a small volume surrounded by bones that makes tractography difficult to perform. We aim to provide a review collecting all technical settings of SC tractography and propose the optimal set of parameters to perform a good SC tractography rendering. The MEDLINE database was searched for articles reporting "spinal cord" "tractography" in "humans". Studies were selected only when tractography rendering was displayed and MRI acquisition and tracking parameters detailed. From each study, clinical context, imaging acquisition settings, fiber tracking parameters, region of interest (ROI) design, and quality of the tractography rendering were extracted. Quality of tractography rendering was evaluated by several objective criteria proposed herein. According to the reported studies, to obtain a good tractography rendering, diffusion tensor imaging acquisition should be performed with 1.5 or 3 Tesla MRI, in the axial plane, with > 20 directions; b value: 1000 s mm; right-left phase-encoding direction for cervical SC; isotropic voxel size; and no slice gap. Concerning the tracking process, it should be performed with determinist approach, fractional anisotropy threshold between 0.15 and 0.2, and curvature threshold of 40°. ROI design is an essential step for providing good tractography rendering, and their placement has to consider partial volume effects, magnetic susceptibility effects, and motion artifacts. The review reported herein highlights that successful SC tractography depends on many factors (imaging acquisition settings, fiber tracking parameters, and ROI design) to obtain a good SC tractography rendering.
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http://dx.doi.org/10.1007/s00234-020-02442-8DOI Listing
September 2020

Stereoscopic three-dimensional visualization: interest for neuroanatomy teaching in medical school.

Surg Radiol Anat 2020 Jun 29;42(6):719-727. Epub 2020 Feb 29.

Department of Anatomy, Faculté de médecine Lyon-Est, Université de Lyon, Université Claude Bernard Lyon I, 8 Avenue Rockefeller, 69003, Lyon, France.

Purpose: The anatomy of both the brain and the skull is particularly difficult to learn and to teach. Since their anatomical structures are numerous and gathered in a complex tridimensional (3D) architecture, classic schematical drawing or photography in two dimensions (2D) has difficulties in providing a clear, simple, and accurate message. Advances in photography and computer sciences have led to develop stereoscopic 3D visualization, firstly for entertainment then for education. In the present study, we report our experience of stereoscopic 3D lecture for neuroanatomy teaching to early medical school students.

Methods: High-resolution specific pictures were taken on various specimen dissections in the Anatomy Laboratory of the University of Lyon, France. Selected stereoscopic 3D views were displayed on a large dedicated screen using a doubled video projector. A 2-h stereoscopic neuroanatomy lecture was given by two neuroanatomists to third-year medicine students who wore passive 3D glasses. Setting up lasted 30 min and involved four people. The feedback from students was collected and analyzed.

Results: Among the 483 students who have attended the stereoscopic 3D lecture, 195 gave feedback, and all (100%) were satisfied. Among these, 190 (97.5%) reported a better knowledge transfer of brain anatomy and its 3D architecture. Furthermore, 167 (86.1%) students felt it could change their further clinical practice, 179 (91.8%) thought it could enhance their results in forthcoming anatomy examinations, and 150 (76.9%) believed such a 3D lecture might allow them to become better physicians. This 3D anatomy lecture was graded 8.9/10 a mean against 5.9/10 for previous classical 2D lectures.

Discussion-conclusion: The stereoscopic 3D teaching of neuroanatomy made medical students enthusiastic involving digital technologies. It could improve their anatomical knowledge and test scores, as well as their clinical competences. Depending on university means and the commitment of teachers, this new tool should be extended to other anatomical fields. However, its setting up requires resources from faculties and its impact on clinical competencies needs to be objectively assessed.
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http://dx.doi.org/10.1007/s00276-020-02442-6DOI Listing
June 2020

Current status and treatment modalities in metastases to the pituitary: a systematic review.

J Neurooncol 2020 Jan 13;146(2):219-227. Epub 2020 Jan 13.

Department of Skull Base and Pituitary Surgery, Neurological Hospital Pierre Wertheimer, Hospices Civils de Lyon, Lyon, France.

Background: Metastases to the pituitary (MP) are uncommon, accounting for 0.4% of intracranial metastases. Through advances in neuroimaging and oncological therapies, patients with metastatic cancers are living longer and MP may be more frequent. This review aimed to investigate clinical and oncological features, treatment modalities and their effect on survival.

Methods: A systematic review was performed according to PRISMA recommendations. All cases of MP were included, excepted primary pituitary neoplasms and autopsy reports. Descriptive and survival analyses were then conducted.

Results: The search identified 2143 records, of which 157 were included. A total of 657 cases of MP were reported, including 334 females (50.8%). The mean ± standard deviation age was 59.1 ± 11.9 years. Lung cancer was the most frequent primary site (31.0%), followed by breast (26.2%) and kidney cancers (8.1%). Median survival from MP diagnosis was 14 months. Overall survival was significantly different between lung, breast and kidney cancers (P < .0001). Survival was impacted by radiotherapy (hazard ratio (HR) 0.49; 95% confidence interval (CI) 0.35-0.67; P < .0001) and chemotherapy (HR 0.58; 95% CI 0.36-0.92; P = .013) but not by surgery. Stereotactic radiotherapy tended to improve survival over conventional radiotherapy (HR 0.66; 95% CI 0.39-1.12; P = .065). Patients from recent studies (≥ 2010) had longer survival than others (HR 1.36; 95% CI 1.05-1.76; P = .0019).

Conclusion: This systematic review based on 657 cases helped to better identify clinical features, oncological characteristics and the effect of current therapies in patients with MP. Survival patterns were conditioned upon primary cancer histologies, the use of local radiotherapy and systemic chemotherapy, but not by surgery.
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http://dx.doi.org/10.1007/s11060-020-03396-wDOI Listing
January 2020

Could non-invasive brain stimulation help treat dysarthria? A single-case study.

Ann Phys Rehabil Med 2020 Jan 12;63(1):81-84. Epub 2019 Jul 12.

Inserm UMR-S 1028, CNRS UMR 529, ImpAct, Centre de Recherche en Neurosciences de Lyon, université Lyon-1, 16, avenue Lépine, 69676 Bron, France; Service de rééducation neurologique, Hôpital Henry-Gabrielle, Hôpital Neurologique, Hospices Civils de Lyon, Lyon, France; Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France. Electronic address:

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http://dx.doi.org/10.1016/j.rehab.2019.06.011DOI Listing
January 2020

Anatomy of the human spinal cord arachnoid cisterns: applications for spinal cord surgery.

J Neurosurg Spine 2019 Jul 12:1-8. Epub 2019 Jul 12.

1Department of Neurosurgery, Hôpital Neurologique et Neurochirurgical Pierre Wertheimer, Hospices Civils de Lyon.

Objective: The goal in this study was to describe the overall organization of the spinal arachnoid mater and spinal subarachnoid space (SSAS) as well as its relationship with surrounding structures, in order to highlight spinal cord arachnoid cisterns.

Methods: Fifteen spinal cords were extracted from embalmed adult cadavers. The organization of the spinal cord arachnoid and SSAS was described via macroscopic observations, optical microscopic views, and scanning electron microscope (SEM) studies. Gelatin injections were also performed to study separated dorsal subarachnoid compartments.

Results: Compartmentalization of SSAS was studied on 3 levels of axial sections. On an axial section passing through the tips of the denticulate ligament anchored to the dura, 3 subarachnoid cisterns were observed: 2 dorsolateral and 1 ventral. On an axial section passing through dural exit/entrance of rootlets, 5 subarachnoid cisterns were observed: 2 dorsolateral, 2 lateral formed by dorsal and ventral rootlets, and 1 ventral. On an axial section passing between the two previous ones, only 1 subarachnoid cistern was observed around the spinal cord. This compartmentalization resulted in the anatomical description of 3 elements: the median dorsal septum, the arachnoid anchorage to the tip of the denticulate ligament, and the arachnoid anchorage to the dural exit/entrance of rootlets. The median dorsal septum already separated dorsal left and right subarachnoid spaces and was described from C1 level to 3 cm above the conus medullaris. This septum was anchored to the dorsal septal vein. No discontinuation was observed in the median dorsal arachnoid septum. At the entrance point of dorsal rootlets in the spinal cord, arachnoid trabeculations were described. Using the SEM, numerous arachnoid adhesions between the ventral surface of the dorsal rootlets and the pia mater over the spinal cord were observed. At the ventral part of the SSAS, no septum was found, but some arachnoid trabeculations between the arachnoid and the pia mater were present and more frequent than in the dorsal part. Laterally, arachnoid was firmly anchored to the denticulate ligaments' fixation at dural points, and dural exit/entrance of rootlets made a fibrous ring of arachnoidodural adhesions. At the level of the cauda equina, the arachnoid mater surrounded all rootlets together-as a sac and not individually.

Conclusions: Arachnoid cisterns are organized on each side of a median dorsal septum and compartmentalized in relation with the attachments of denticulate ligament and exit/entrance of rootlets.
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http://dx.doi.org/10.3171/2019.4.SPINE19404DOI Listing
July 2019

Extra-intradural extracavernous subtemporal approach for chondrosarcomas: technical note and case report.

Acta Neurochir (Wien) 2019 11 4;161(11):2349-2352. Epub 2019 Jul 4.

Skull Base Surgery Unit, Department of Neurosurgery B, Hospices Civils de Lyon, University Hospital of Lyon, Lyon, France.

Background: Skull base chondrosarcomas are rare tumors often invading the petrous apex and cavernous sinus, and many surgical approaches have been described. For most of them, these tumors grow slowly and their partial removal can be a first option before complementary radiotherapy. We described herein a minimally invasive approach that could be useful for soft non-calcified chondrosarcomas.

Method And Results: We report a case of right parasellar chondrosarcoma, for which an extra-intradural extracavernous subtemporal approach allowed a safe effective partial removal.

Conclusion: This surgical approach is indicated in selected cases to obtain good decompression or partial removal of lesions involving the parasellar space and the petrous apex.
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http://dx.doi.org/10.1007/s00701-019-03989-zDOI Listing
November 2019

Full tractography for detecting the position of cranial nerves in preoperative planning for skull base surgery: technical note.

J Neurosurg 2019 Apr 19;132(5):1642-1652. Epub 2019 Apr 19.

4Department of Neurosurgery, Stanford University Medical Center, Stanford, California.

Objective: Diffusion imaging tractography has allowed the in vivo description of brain white matter. One of its applications is preoperative planning for brain tumor resection. Due to a limited spatial and angular resolution, it is difficult for fiber tracking to delineate fiber crossing areas and small-scale structures, in particular brainstem tracts and cranial nerves. New methods are being developed but these involve extensive multistep tractography pipelines including the patient-specific design of multiple regions of interest (ROIs). The authors propose a new practical full tractography method that could be implemented in routine presurgical planning for skull base surgery.

Methods: A Philips MRI machine provided diffusion-weighted and anatomical sequences for 2 healthy volunteers and 2 skull base tumor patients. Tractography of the full brainstem, the cerebellum, and cranial nerves was performed using the software DSI Studio, generalized-q-sampling reconstruction, orientation distribution function (ODF) of fibers, and a quantitative anisotropy-based generalized deterministic algorithm. No ROI or extensive manual filtering of spurious fibers was used. Tractography rendering was displayed in a tridimensional space with directional color code. This approach was also tested on diffusion data from the Human Connectome Project (HCP) database.

Results: The brainstem, the cerebellum, and the cisternal segments of most cranial nerves were depicted in all participants. In cases of skull base tumors, the tridimensional rendering permitted the visualization of the whole anatomical environment and cranial nerve displacement, thus helping the surgical strategy.

Conclusions: As opposed to classical ROI-based methods, this novel full tractography approach could enable routine enhanced surgical planning or brain imaging for skull base tumors.
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http://dx.doi.org/10.3171/2019.1.JNS182638DOI Listing
April 2019

Understanding Anatomy of the Petrous Pyramid-A New Compartmental Approach.

World Neurosurg 2019 Jan 5. Epub 2019 Jan 5.

Department of Anatomy, University of Lyon 1, Lyon, France; Skull Base Multi-disciplinary Unit, Department of Neurosurgery B, Neurological Hospital Pierre Wertheimer, Hospices Civils de Lyon, Lyon Cedex, France.

Background: Learning surgical anatomy of the petrous pyramid can be a challenge, especially in the beginning of the training process. Providing an easier, holistic approach can be of help to everyone with interest in learning and teaching skull base anatomy. We present the complex organization of petrous pyramid anatomy using a new compartmental approach that is simple to understand and remember.

Methods: The surfaces of the petrous pyramid of two temporal bones were examined; and the contents of the petrous pyramid of 8 temporal bones were exposed through progressive drilling of the superior surface.

Results: The petrous pyramid is made up of a bony container, and its contents were grouped into 4 compartments (mucosal, cutaneous, neural, and vascular). Two reference lines were identified (mucosal and external-internal auditory canal lines) intersecting at the level of the middle ear. The localization of contents relative to these reference lines was then described, and 2 methods of segmentation (the X method and the V method) were then proposed. This description was then used to describe middle ear relationships, facial nerve anatomy, and air cell distribution.

Conclusions: This new compartmental approach allows a comprehensive understanding of the distribution of petrous pyramid contents. Dividing it into anatomic compartments, and then navigating this mental map along specific reference points, lines, spaces, and segments, could create a useful tool to teach or learn its complex tridimensional anatomy.
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http://dx.doi.org/10.1016/j.wneu.2018.11.234DOI Listing
January 2019

Tractography for Surgical Neuro-Oncology Planning: Towards a Gold Standard.

Neurotherapeutics 2019 01;16(1):36-51

Department of Neurosurgery, Stanford University, 300 Pasteur Drive, Palo Alto, CA, 94304, USA.

Magnetic resonance imaging tractography permits in vivo visualization of white matter structures. Aside from its academic value, tractography has been proven particularly useful to neurosurgeons for preoperative planning. Preoperative tractography permits both qualitative and quantitative analyses of tumor effects upon surrounding white matter, allowing the surgeon to specifically tailor their operative approach. Despite its benefits, there is controversy pertaining to methodology, implementation, and interpretation of results in this context. High-definition fiber tractography (HDFT) is one of several non-tensor tractography approaches permitting visualization of crossing white matter trajectories at high resolutions, dispensing with the well-known shortcomings of diffusion tensor imaging (DTI) tractography. In this article, we provide an overview of the advantages of HDFT in a neurosurgical context, derived from our considerable experience implementing the technique for academic and clinical purposes. We highlight nuances of qualitative and quantitative approaches to using HDFT for brain tumor surgery planning, and integration of tractography with complementary operative adjuncts, and consider areas requiring further research.
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http://dx.doi.org/10.1007/s13311-018-00697-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6361069PMC
January 2019

Probabilistic Tractography to Predict the Position of Cranial Nerves Displaced by Skull Base Tumors: Value for Surgical Strategy Through a Case Series of 62 Patients.

Neurosurgery 2019 07;85(1):E125-E136

CREATIS Laboratory CNRS UMR5220, Inserm U1206, INSA-Lyon, University of Lyon 1, Lyon, France.

Background: Predicting the displacement of cranial nerves by tumors could make surgery safer and the outcome better. Recent advances in imaging and processing have overcome some of the limits associated with cranial nerve tractography, such as spatial resolution and fiber crossing. Among others, probabilistic algorithms yield to a more accurate depiction of cranial nerve trajectories.

Objective: To report how cranial nerve probabilistic tractography can help the surgical strategy in a series of various skull base tumors.

Methods: After distortion correction and region of interest seeding, a probabilistic tractography algorithm used the constrained spherical deconvolution model and attempted the reconstruction of cranial nerve trajectories in both healthy and displaced conditions.

Results: Sixty-two patients were included and presented: vestibular schwannomas (n = 33); cerebellopontine angle meningiomas (n = 15); arachnoid or epidermoid cysts (n = 6); cavernous sinus and lower nerves schwannomas (n = 4); and other tumors (n = 4). For each patient, at least one 'displaced' cranial nerve was not clearly identified on classical anatomical MRI images. All 372 cranial nerves were successfully tracked on each healthy side; among the 175 cranial nerves considered 'displaced' by tumors, 152 (87%) were successfully tracked. Among the 127 displaced nerves of operated patients (n = 51), their position was confirmed intraoperatively for 118 (93%) of them. Conditions that led to tractography failure were detailed. On the basis of tractography, the surgical strategy was adjusted for 44 patients (71%).

Conclusion: This study reports a cranial nerve probabilistic tractography pipeline that can: predict the position of most cranial nerves displaced by skull base tumors, help the surgical strategy, and thus be a pertinent tool for future routine clinical application.
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http://dx.doi.org/10.1093/neuros/nyy538DOI Listing
July 2019

Overcoming Challenges of Cranial Nerve Tractography: A Targeted Review.

Neurosurgery 2019 02;84(2):313-325

CREATIS Laboratory CNRS UMR5220, Inserm U1206, INSA-Lyon, University of Lyon 1, Lyon, France.

Background: Diffusion imaging tractography caught the attention of the scientific community by describing the white matter architecture in vivo and noninvasively, but its application to small structures such as cranial nerves remains difficult. The few attempts to track cranial nerves presented highly variable acquisition and tracking settings.

Objective: To conduct and present a targeted review collecting all technical details and pointing out challenges and solutions in cranial nerve tractography.

Methods: A "targeted" review of the scientific literature was carried out using the MEDLINE database. We selected studies that reported how to perform the tractography of cranial nerves, and extracted the following: clinical context; imaging acquisition settings; tractography parameters; regions of interest (ROIs) design; and filtering methods.

Results: Twenty-one published articles were included. These studied the optic nerves in suprasellar tumors, the trigeminal nerve in neurovascular conflicts, the facial nerve position around vestibular schwannomas, or all cranial nerves. Over time, the number of MRI diffusion gradient directions increased from 6 to 101. Nine tracking software packages were used which offered various types of tridimensional display. Tracking parameters were disparately detailed except for fractional anisotropy, which ranged from 0.06 to 0.5, and curvature angle, which was set between 20° and 90°. ROI design has evolved towards a multi-ROI strategy. Furthermore, new algorithms are being developed to avoid spurious tracts and improve angular resolution.

Conclusion: This review highlights the variability in the settings used for cranial nerve tractography. It points out challenges that originate both from cranial nerve anatomy and the tractography technology, and allows a better understanding of cranial nerve tractography.
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http://dx.doi.org/10.1093/neuros/nyy229DOI Listing
February 2019

MRI Tractography Detecting Cranial Nerve Displacement in a Cystic Skull Base Tumor.

World Neurosurg 2018 Sep 30;117:363-365. Epub 2018 Jun 30.

University of Lyon, INSA-Lyon, Université Claude Bernard Lyon 1, UJM-Saint Etienne, CNRS, Inserm, Lyon, France.

A 37-year-old man came to our neurosurgical department with a 2-month history of a progressive invalidating balance disorder. Cerebral magnetic resonance imaging found a T2-weighted hypersignal lesion of the right cerebellopontine angle that severely compressed the brainstem, however the position of cranial nerves was not clearly identified. The new MRI diffusion tool, tractography, allowed to reconstruct the trajectory of cranial nerves that were displaced by the tumor. As such, the acoustic facial bundle was severely flattened posteriorly and superiorly, while the lower nerves were pushed inferiorly. Effective neurosurgical decompression was performed and confirmed the position of cranial nerves V-XII. The patient was discharged and returned home without any cranial nerve deficit. This case illustrates how advances in imaging can now better describe the anatomy surrounding brain tumors and make surgery safer to the benefit of patients.
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http://dx.doi.org/10.1016/j.wneu.2018.06.182DOI Listing
September 2018

A Quantitative Tractography Study Into the Connectivity, Segmentation and Laterality of the Human Inferior Longitudinal Fasciculus.

Front Neuroanat 2018 5;12:47. Epub 2018 Jun 5.

Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, PA, United States.

The human inferior longitudinal fasciculus (ILF) is a ventral, temporo-occipital association tract. Though described in early neuroanatomical works, its existence was later questioned. Application of tractography to the neuroanatomical study of the ILF has generally confirmed its existence, however, consensus is lacking regarding its subdivision, laterality and connectivity. Further, there is a paucity of detailed neuroanatomic data pertaining to the exact anatomy of the ILF. Generalized Q-Sampling imaging (GQI) is a non-tensor tractographic modality permitting high resolution imaging of white-matter structures. As it is a non-tensor modality, it permits visualization of crossing fibers and accurate delineation of close-proximity fiber-systems. We applied deterministic GQI tractography to data from 30 healthy subjects and a large-volume, averaged diffusion atlas, to delineate ILF anatomy. Post-mortem white matter dissection was also carried out in three cadaveric specimens for further validation. The ILF was found in all 60 hemispheres. At its occipital extremity, ILF fascicles demonstrated a bifurcated, ventral-dorsal morphological termination pattern, which we used to further subdivide the bundle for detailed analysis. These divisions were consistent across the subject set and within the atlas. We applied quantitative techniques to study connectivity strength of the ILF at its anterior and posterior extremities. Overall, both morphological divisions, and the un-separated ILF, demonstrated strong leftward-lateralized connectivity patterns. Leftward-lateralization was also found for ILF volumes across the subject set. Due to connective and volumetric leftward-dominance and ventral location, we postulate the ILFs role in the semantic system. Further, our results are in agreement with functional and lesion-based postulations pertaining to the ILFs role in facial recognition.
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http://dx.doi.org/10.3389/fnana.2018.00047DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5996125PMC
June 2018

Delayed Posttraumatic Subacute Lumbar Subarachnoid Hematoma: Case Report and Review of the Literature.

World Neurosurg 2018 May 14;113:135-139. Epub 2018 Feb 14.

Department of Neurosurgery, Lyon University Hospital, Hospices Civils de Lyon, Bron, France; CREATIS Laboratory, Lyon University, Lyon, France. Electronic address:

Background: Traumatic spinal subarachnoid hematoma, associated or not with a concurrent subdural hematoma, has rarely been described. The evolution of such hematomas is heterogeneous. This study aims at defining the most accurate management, which is currently not standardized.

Case Description: A 20-year-old man, victim of a high-kinetic road accident 5 days before and with several nonneurologic nonsurgical vertebral fractures, experienced a sudden dorsolumbar pain radiating to his lower limbs. A rapidly progressive asymmetric paraparesis with loss of reflexes was noticed, associated with bilateral global hypoesthesia of the lower limbs and with acute urinary retention, whereas the anal tonicity was preserved (American Spinal Injury Association C). Magnetic resonance imaging scan revealed a conus medullaris compression at the level of the L1-L2 vertebrae by an intradural expansive mass. Immediate surgical decompression revealed a strictly subarachnoid hematoma. Venous bleeding was seen at the level of the conus medullaris and controlled. Pathologic examination of the clot excluded an underlying tumor or vascular abnormality. The complete coagulation profile was normal.

Conclusion: Six weeks after surgery, the neurologic examination revealed only a slight tactile hypoesthesia of the left thigh. With only 4 reported cases, purely subarachnoid spinal hematomas remain widely rarer than epidural hematomas. The reported case possesses a certain number of peculiarities: young age, pure subarachnoid location, lumbar location, occurrence after a car accident, subacute onset, and excellent neurologic recovery. In our opinion, a symptomatic subarachnoid spinal hematoma should be surgically evacuated at the early phase so neurologic recovery can be expected.
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http://dx.doi.org/10.1016/j.wneu.2018.02.035DOI Listing
May 2018

Liponeurocytoma of the Cerebellopontine Angle.

World Neurosurg 2018 Apr 8;112:18-24. Epub 2018 Jan 8.

Skull Base Surgery Unit, Department of Neurosurgery B, University Hospital of Lyon, Hospices Civils de Lyon, Lyon, France; CREATIS Laboratory, CNRS UMR5220, INSERM U1206, Lyon 1 University, INSA, Lyon, France. Electronic address:

Background: Liponeurocytoma is a very rare tumor classified as grade II (neuronal and mixed neuronal-glial tumors) according to 2016 World Health Organization classification of tumors of the central nervous system. The median age at detection is 50 years, and the most frequent location is the posterior cranial fossa, especially within the cerebellar hemispheres; liponeurocytomas arising in the cerebellopontine angle (CPA) are exceptional.

Case Description: Here we report the clinical, radiological, and pathological characteristics of a CPA liponeurocytoma in a 35-year-old woman, as well as a review of the literature. This unusual cisternal location raises the issue of the differential imaging diagnosis with much more common CPA tumors (e.g., meningiomas, vestibular schwannomas, ependymomas, epidermoid cyst, hemangioblastomas, medulloblastomas).

Conclusion: To the best of our knowledge, 59 cases of cerebellar liponeurocytomas have been reported to date, which include only 6 cases of CPA liponeurocytomas. Treatment relies on total removal whenever possible, with an excellent prognosis, but a high MIB-1 index (>10%) and/or incomplete tumor resection are the main adverse prognostic factors.
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http://dx.doi.org/10.1016/j.wneu.2018.01.012DOI Listing
April 2018

Pathogenesis of peri-tumoral edema in intracranial meningiomas.

Neurosurg Rev 2019 Mar 24;42(1):59-71. Epub 2017 Aug 24.

Laboratory CREATIS - CNRS UMR5220 - INSERM U1206 - Lyon 1 University - INSA, Lyon, France.

Peri-tumoral edema in intracranial meningiomas occurs frequently and obviously impacts the morbidity and mortality of these predominantly benign neoplasms. Several causative factors (age, gender, volume, location…) have been unsuccessfully investigated. Despite recent progresses in metabolic imaging and molecular biology, the pathogenesis of peri-tumoral edema remains debated. Hypotheses include vascular endothelial growth factor, metalloproteinases and interleukins among many others. It is probable that this pathogenesis encompasses all these factors with different levels. The current review aims to shed the light on the investigated factors involved in the pathogenesis of peri-tumoral edema in meningiomas and identify the potential therapeutic targets.
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http://dx.doi.org/10.1007/s10143-017-0897-xDOI Listing
March 2019

Diffusion Tensor Imaging Tractography Detecting Isolated Oculomotor Nerve Damage After Traumatic Brain Injury.

World Neurosurg 2017 Apr 31;100:707.e5-707.e7. Epub 2017 Jan 31.

CREATIS Laboratory, CNRS UMR 5220 - INSERM U1044, Villeurbanne, France; Department of Radiology, Lyon Sud Hospital, Hospices Civils de Lyon, Lyon, France.

A 24-year-old woman was hit by a bus and suffered an isolated complete oculomotor nerve palsy. Computed tomography scan did not show a skull base fracture. T2*-weighted magnetic resonance imaging revealed petechial cerebral hemorrhages sparing the brainstem. T2 constructive interference in steady state suggested a partial sectioning of the left oculomotor nerve just before entering the superior orbital fissure. Diffusion tensor imaging fiber tractography confirmed a sharp arrest of the left oculomotor nerve. This recent imaging technique could be of interest to assess white fiber damage and help make a diagnosis or prognosis.
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http://dx.doi.org/10.1016/j.wneu.2017.01.082DOI Listing
April 2017

The 360 photography: a new anatomical insight of the sphenoid bone. Interest for anatomy teaching and skull base surgery.

Surg Radiol Anat 2017 Jan 2;39(1):17-22. Epub 2016 Jun 2.

Department of Anatomy, University of Lyon 1, 8 Avenue Rockefeller, 69003, Lyon, France.

Skull base architecture is tough to understand because of its 3D complex shape and its numerous foramen, reliefs or joints. It is especially true for the sphenoid bone whom central location hinged with most of skull base components is unique. Recently, technological progress has led to develop new pedagogical tools. This way, we bought a new real-time three-dimensional insight of the sphenoid bone that could be useful for the teacher, the student and the surgeon. High-definition photography was taken all around an isolated dry skull base bone prepared with Beauchêne's technique. Pictures were then computed to provide an overview with rotation and magnification on demand. From anterior, posterior, lateral or oblique views and from in out looks, anatomical landmarks and subtleties were described step by step. Thus, the sella turcica, the optic canal, the superior orbital fissure, the sphenoid sinus, the vidian canal, pterygoid plates and all foramen were clearly placed relative to the others at each face of the sphenoid bone. In addition to be the first report of the 360 Photography tool, perspectives are promising as the development of a real-time interactive tridimensional space featuring the sphenoid bone. It allows to turn around the sphenoid bone and to better understand its own special shape, numerous foramen, neurovascular contents and anatomical relationships. This new technological tool may further apply for surgical planning and mostly for strengthening a basic anatomical knowledge firstly introduced.
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http://dx.doi.org/10.1007/s00276-016-1702-1DOI Listing
January 2017

Pathogenesis of Delayed Tension Intraventricular Pneumocephalus in Shunted Patient: Possible Role of Nocturnal Positive Pressure Ventilation.

World Neurosurg 2016 Jan 9;85:365.e17-20. Epub 2015 Sep 9.

Department of Neurosurgery B, Pierre Wertheimer Neurological and Neurosurgical Hospital, Hospices Civils de Lyon, France. Electronic address:

Background: Delayed intraventricular pneumocephalus is a very rare and potentially serious complication of ventriculoperitoneal shunt. It can occur several months or years after shunting. Its pathogenesis is unclear. We herein discuss the underlying mechanisms and particularly the possible role of positive pressure ventilation.

Case Description: A 60 year-old man presented with a lateral ventricle neurocytoma microsurgically resected complicated by a late-onset (15 months) postoperative hydrocephalus requiring an adjustable ventriculoperitoneal (VP) shunt. One month later, the patient was diagnosed with a sleep apnea and required a continuous positive airway pressure (CPAP) device. A few weeks afterward the patient presented with headaches and alteration of consciousness. CT-Scan revealed a massive intraventricular pneumocephalus associated with a millimetric left petrous bone defect. A transient breakout of the positive ventilation and a subtemporal surgical repair of the defect led to the rapid resolution of the pneumocephalus.

Discussion: Delayed intraventricular pneumocephalus requires two conditions: a VP shunt and an osteodural defect. The CPAP may play an important trigger role in the pathogenesis of this complication through a ball valve mechanism. The management relies on transient suspension of the positive ventilation and the surgical repair of the identified defect with or without pressure adjustments of the valve.

Conclusion: Intraventricular pneumocephalus is a potentially serious complication of patients with a VP shunt and receiving positive pressure ventilation. The introduction of a CPAP device must be discussed with the neurosurgeon beforehand in shunted patients.
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http://dx.doi.org/10.1016/j.wneu.2015.09.001DOI Listing
January 2016

Anatomic comparison of anterior petrosectomy versus the expanded endoscopic endonasal approach: interest in petroclival tumors surgery.

Surg Radiol Anat 2015 Dec 12;37(10):1199-207. Epub 2015 Jun 12.

Skull Base Multi-disciplinary Unit, Department of Neurosurgery B, Neurological Hospital Pierre Wertheimer, Hospices Civils de Lyon, 59 Bd Pinel, 69677, Lyon Cedex, France.

Purpose: Since the petroclival region is deep-seated with close neurovascular relationships, the removal of petroclival tumors still represents a fascinating surgical challenge. Although the classical anterior petrosectomy (AP) offers a meaningful access to this petroclival region, the expanded endoscopic endonasal approach (EEEA) recently leads to overcome difficulties from trans-cranial approaches. Herein, we present an anatomic comparison of AP versus EEEA. We aim to describe the limits of these both approaches helping the choice of the optimal surgical route for petroclival tumors.

Methods: Six fresh cadaveric heads were harvested and injected with colored latex. Each approach was step-by-step detailed until its final surgical exposure.

Results: The AP provided a narrow direct supero-lateral access to the petroclival area that can also reach the cavernous sinus, the retrochiasmatic region and perimesencephalic cisterns. However, this corridor anterior to the internal acoustic meatus passed on each side of the trigeminal nerve. Moreover, tumor extensions toward the foramen jugularis, inside the clivus or behind the internal acoustic meatus were difficult to control. The EEEA brought a straightforward access to the clivus but the petrous apex was hidden behind the internal carotid artery. Several variants were described: a medial transclival, a lateral through the Meckel's cave and an inferior trans-pterygoid route. Elsewhere, tumor extension behind the internal acoustic meatus or above the tentorium could not be satisfactorily assessed.

Discussion And Conclusion: PA and EEEA have their own limits in reaching the petroclival region in accordance with the tumor characteristics. The AP should be preferred for radical removal of middle-sized petrous apex intradural tumors like meningiomas. The EEEA would be of interest for extradural midline tumors like chordomas or for petrous apex cysts drainage.
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http://dx.doi.org/10.1007/s00276-015-1497-5DOI Listing
December 2015

Total removal of a trigeminal schwannoma via the expanded endoscopic endonasal approach. Technical note.

Acta Neurochir (Wien) 2015 Jun 7;157(6):935-8; discussion 938. Epub 2015 Apr 7.

Multidisciplinary Skull Base Unit, Department of Neurosurgery B, Neurological Hospital Pierre Wertheimer, Hospices Civils de Lyon, 59 Bd Pinel, 69677, Lyon Cedex, France,

Background: Because of their deep location surrounded by closed numerous neurovascular structures, skull base tumors of the cavernous sinus are still difficult to manage. Recently, the endoscopic endonasal approach commonly used for pituitary tumor resection has been "expanded" to the parasellar, infratemporal and orbital compartments with some advantages compared to the intracranial route.

Methods: The authors reported the case of a 49-year-old male presenting a large extradural tumor of the left cavernous sinus with extensions toward the orbit, sphenoid sinus and infratemporal fossa. His ophthalmological examination was normal, and the body CT scan revealed no primary neoplasm.

Results: In this operative video, the approach is described step by step with surgical nuances. The endoscopy provided a close-up panoramic view and various angles of vision. Also, it avoided an invasive craniotomy, cerebral retraction and cranial nerves damages. Thus, it allowed the total removal of this tumor originating from the maxillary branch of the trigeminal nerve. The pathologic examination confirmed a schwannoma.

Conclusion: The expanded endoscopic endonasal approach provides an interesting corridor to cavernous sinus tumors with satisfactory control of extensions inferiorly toward the infratemporal fossa, anteriorly via the superior orbital fissure and medially within the sphenoid. Finally, the skull base surgeon has to master this anterior endoscopic route as well as all the other "open" transcranial skull base approaches to propose the best surgical route fitting the tumor characteristics.
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http://dx.doi.org/10.1007/s00701-015-2409-5DOI Listing
June 2015

Which Routes for Petroclival Tumors? A Comparison Between the Anterior Expanded Endoscopic Endonasal Approach and Lateral or Posterior Routes.

World Neurosurg 2015 Jun 17;83(6):929-36. Epub 2015 Feb 17.

Skull Base Multidisciplinary Unit, Department of Neurosurgery, Neurological Hospital Pierre Wertheimer, Lyon Cedex, France.

Objective: Petroclival tumors remain a surgical challenge. Classically, the retrosigmoid approach (RSA) has long been used to reach such tumors, whereas the anterior petrosectomy (AP) has been proposed to avoid crossing cranial nerves. More recently, the endoscopic endonasal approach has been "expanded" (i.e., EEEA) to the petroclival region. We aimed to compare these 3 approaches to help in the surgical management of petroclival tumors.

Methods: Petroclival approaches were performed on 5 specimens after they were prepared with formaldehyde colored via latex injection.

Results: The EEEA provides a simple straightforward route to the clivus, but reaching the petrous apex requires the surgeon to circumvent the internal carotid artery either via a medial transclival, an inferior transpterygoid, or a lateral variant through the Meckel's cave. In contrast, the AP offers a narrow direct superolateral access to the petroclival region crossed by the trigeminal nerve. Finally, the RSA provides a wide simple and quick exposure of the cerebellopontine angle, but access to the petroclival region needs the surgeon to deal with the V(th) to XI(th) cranial nerves.

Discussion/conclusion: The EEEA should be preferred for extradural midline tumors (chordomas, chondrosarcomas) or for cystic lesions when drainage is essential. The AP could be optimal for the radical removal of intradural vascularized tumors (meningiomas) with intrapetrous or supratentorial extensions. The RSA retains an advantage for small or cystic tumors near the internal acoustic meatus. The skull base surgeon has to master all of these routes to choose the more appropriate one according to the surgical objective, the tumor characteristics, and the patient's medical status.
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http://dx.doi.org/10.1016/j.wneu.2015.02.003DOI Listing
June 2015

Response to: "considerations about endoscopic endonasal optic nerve and orbital apex decompression".

Acta Neurochir (Wien) 2015 Apr 5;157(4):631-2. Epub 2015 Feb 5.

Multidisciplinary Skull Base Surgery Unit, Department of Neurosurgery B, Pierre Wertheimer Neurological and Neurosurgical Hospital, Hospices Civils de Lyon, 59 Boulevard Pinel, 69677, Lyon Cedex, France,

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http://dx.doi.org/10.1007/s00701-015-2357-0DOI Listing
April 2015

Endoscopic endonasal optic nerve and orbital apex decompression for nontraumatic optic neuropathy: surgical nuances and review of the literature.

Neurosurg Focus 2014 ;37(4):E19

Skull Base Surgery Unit, Department of Neurosurgery B, Pierre Wertheimer Neurological and Neurosurgical Hospital, Hospices Civils de Lyon.

Object: While several approaches have been described for optic nerve decompression, the endoscopic endonasal route is gaining favor because it provides excellent exposure of the optic canal and the orbital apex in a minimally invasive manner. Very few studies have detailed the experience with nontraumatic optic nerve decompressions, whereas traumatic cases have been widely documented. Herein, the authors describe their preliminary experience with endoscopic endonasal decompression for nontraumatic optic neuropathies (NONs) to determine the procedure's efficacy and delineate its potential indications and limits.

Methods: The medical reports of patients who had undergone endoscopic endonasal optic nerve and orbital apex decompression for NONs at the Lyon University Neurosurgical Hospital in the period from January 2012 to March 2014 were reviewed. For all cases, clinical and imaging data on the underlying pathology and the patient, including demographics, preoperative and 6-month postoperative ophthalmological assessment results, symptom duration, operative details with video debriefing, as well as the immediate and delayed postoperative course, were collected from the medical records.

Results: Eleven patients underwent endoscopic endonasal decompression for NON in the multidisciplinary skull base surgery unit of the Lyon University Neurosurgical Hospital during the 27-month study period. The mean patient age was 53.4 years, and there was a clear female predominance (8 females and 3 males). Among the underlying pathologies were 4 sphenoorbital meningiomas (36%), 3 optic nerve meningiomas (27%), and 1 each of trigeminal neuroma (9%), orbital apex meningioma (9%), ossifying fibroma (9%), and inflammatory pseudotumor of the orbit (9%). Fifty-four percent of the patients had improved visual acuity at the 6-month follow-up. Only 1 patient whose sphenoorbital meningioma had been treated at the optic nerve atrophy stage continued to worsen despite surgical decompression. The 2 patients presenting with preoperative papilledema totally recovered. One case of postoperative epistaxis was successfully treated using balloon inflation, and 1 case of air swelling of the orbit spontaneously resolved.

Conclusions: Endoscopic endonasal optic nerve decompression is a safe, effective, and minimally invasive technique affording the restoration of visual function in patients with nontraumatic compressive processes of the orbital apex and optic nerve. The timing of decompression remains crucial, and patients should undergo such a procedure early in the disease course before optic atrophy.
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http://dx.doi.org/10.3171/2014.7.FOCUS14303DOI Listing
June 2015

How I do it: the endoscopic endonasal optic nerve and orbital apex decompression.

Acta Neurochir (Wien) 2014 Oct 22;156(10):1891-6. Epub 2014 Aug 22.

Skull Base Surgery Unit - Department of Neurosurgery B, Pierre Wertheimer Neurological and Neurosurgical Hospital - Hospices Civils de Lyon, Lyon, France,

Background: With the refinement of the technique, endoscopic endonasal surgery increases its field of indications. The orbital compartment is among the locations easily reached through the nostril. This anteromedial approach has been described primarily for inflammatory or traumatic diseases, with few data for tumoral diseases.

Method: Since 2010, this route has been used at our institution either for decompression or for biopsy of orbital tumoral diseases.

Findings/conclusions: Even if further studies are warranted, this strategy proved to be beneficial for patients, with improvements in visual outcome. In this article, the authors summarize their technique and their experience with endonasal endoscopic orbital decompression.

Key Points: Nasal and sphenoidal anatomies determine the feasibility and risks for doing an efficient medial optic or orbit decompression. • Techniques and tools used are those developed for pituitary surgery. • A middle turbinectomy and posterior ethmoidectomy are mandatory to expose the medial wall of the orbit. • The Onodi cell is a key marker for the optic canal and must be opened up with caution. • The lamina papyracea is opened first with a spatula and the optic canal opened up by a gentle drilling under continuous irrigation from distal to proximal. • Drilling might always be used under continuous irrigation to avoid overheating of the optic nerve. An ultrasonic device can be used as well. • The nasal corridor is narrow and instruments may hide the infrared neuronavigation probe. To overcome this issue, a magnetic device could be useful. • Doppler control could be useful to locate the ICA. • The optic canal must be opened up from the tuberculum of the sella to the orbital apex and from the planum (anterior cranial fossa) to the lateral OCR or ICA canal • At the end of the procedure, the optic nerve becomes frequently pulsatile, which is a good marker of decompression.
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http://dx.doi.org/10.1007/s00701-014-2199-1DOI Listing
October 2014

The endoscopic endonasal approach to the Meckel's cave tumors: surgical technique and indications.

World Neurosurg 2014 Dec 12;82(6 Suppl):S155-61. Epub 2014 Aug 12.

Department of Neurosurgery A, Pierre Wertheimer Hospital, Hospices Civils de Lyon, Lyon 1 University, Lyon, France.

Many benign and malignant tumors as well as other inflammatory or vascular diseases may be located in the areas of Meckel's cave or the cavernous sinus. Except for typical features such as for meningiomas, imaging may not by itself be sufficient to choose the best therapeutic option. Thus, even though modern therapy (chemotherapy, radiotherapy, or radiosurgery) dramatically reduces the field of surgery in this challenging location, there is still some place for surgical biopsy or tumor removal in selected cases. Until recently, the microscopic subtemporal extradural approach with or without orbitozygomatic removal was classically used to approach Meckel's cave but with a non-negligible morbidity. Percutaneous biopsy using the Hartel technique has been developed for biopsy of such tumors but may fail in the case of firm tumors, and additionally it is not appropriate for anterior parasellar tumors. With the development of endoscopy, the endonasal route now represents an interesting alternative approach to Meckel's cave as well as the cavernous sinus. Through our experience, we describe the modus operandi and discuss what should be the appropriate indication of the use of the endonasal endoscopic approach for Meckel's cave disease in the armamentarium of the skull base surgeon.
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http://dx.doi.org/10.1016/j.wneu.2014.08.003DOI Listing
December 2014

What is the dorsal median sulcus of the spinal cord? Interest for surgical approach of intramedullary tumors.

Surg Radiol Anat 2014 May 31;36(4):345-51. Epub 2013 Aug 31.

Department of Neurosurgery, Hôpital Neurologique Pierre Wertheimer, 59 Bd Pinel, 69677, Bron, Cedex, France,

Purpose: For intramedullary tumor (IMT) surgery, a balance has to be found between aggressively resecting the tumor and respecting all the sensory and motor pathways. The most common surgical approach is through the dorsal median sulcus (DMS) of the spinal cord. However, the precise organization of the meningeal sheats in the DMS remains obscure in the otherwise well-described anatomy of the spinal cord. A better understanding of this architecture may be of benefit to IMT surgeon to spare the spinal cord.

Methods: Three spinal cords were studied. The organization of the spinal cord meninges in the DMS was described via macroscopic, microsurgical and optical microscopic views. A micro dissection of the DMS was also performed.

Results: No macroscopic morphological abnormalities were observed. With the operative magnifying lens, the dura was opened, the arachnoid was removed and the pia mater was cut to access the DMS. The histological study showed that the DMS was composed of a thin rim of capillary-carrying connective tissue extending from the pia mater and covering the entire DMS. There was no true space between the dorsal columns, no arachnoid or crossing axons either.

Conclusion: Our work indicates that the DMS is not a sulcus but a thin blade of collagen extending from the pia mater. Its location is given by tiny vessels coming from the surface towards the deep. Thus, the surgical corridor has to follow the DMS as closely as possible to prevent damage to the spinal cord during midline IMT removal.
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http://dx.doi.org/10.1007/s00276-013-1194-1DOI Listing
May 2014

The fully endoscopic supraorbital trans-eyebrow keyhole approach to the anterior and middle skull base.

Acta Neurochir (Wien) 2011 Oct 5;153(10):1949-54. Epub 2011 Aug 5.

Skull Base Surgery Unit, Department of Neurosurgery A, Pierre Wertheimer Hospital, Hospices Civils de Lyon, Claude Bernard University, Lyon, France.

Background: The purely endoscopic eyebrow supraorbital approach is an alternative to both the endoscopic endonasal and eyebrow microsurgical routes to the anterior and middle cranial base. It combines an enhanced visualization provided by the endoscope and the absence of cerebrospinal fluid (CSF) leaks and nasal complications.

Methods: A trans-eyebrow 2-cm craniotomy is designed to allow the placement of a straight endoscope and visualize the skull base from the cribriform plate to the mesiotemporal lobe.

Result: Visualization is considerably improved, while the keyhole mini-invasive concept is respected.

Conclusion: The purely endoscopic eyebrow supraorbital keyhole approach is a valuable and alternative minimally invasive route to anterior and middle skull base lesions.
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http://dx.doi.org/10.1007/s00701-011-1089-zDOI Listing
October 2011