The interperiosteodural concept applied to the jugular foramen and its compartmentalization

OBJECTIVE The dura mater is made of 2 layers: the endosteal layer (outer layer), which is firmly attached to the bone, and the meningeal layer (inner layer), which directly covers the brain and spinal cord. These 2 dural layers join together in most parts of the skull base and cranial convexity, and separate into the orbital and perisellar compartments or into the spinal epidural space to form the extradural neural axis compartment (EDNAC). The EDNAC contains fat and/or venous blood. The aim of this dissection study was to anatomically verify the concept of the EDNAC by focusing on the dural layers surrounding the jugular foramen area. METHODS The authors injected 10 cadaveric heads (20 jugular foramina) with colored latex and fixed them in formalin. The brainstem and cerebellum of 7 specimens were cautiously removed to allow a superior approach to the jugular foramen. Special attention was paid to the meningeal architecture of the jugular foramen, the petrosal inferior sinus and its venous confluence with the sigmoid sinus, and the glossopharyngeal, vagus, and accessory nerves. The 3 remaining heads were bleached with a 20% hydrogen peroxide solution. This procedure produced softening of the bone without modifying the fixed soft tissues, thus permitting coronal and axial dissections. RESULTS The EDNAC of the jugular foramen was limited by the endosteal and meningeal layers and contained venous blood. These 2 dural layers joined together at the level of the petrous and occipital bones and separated at the inferior petrosal sinus and the sigmoid sinus, and around the lower cranial nerves, to form the EDNAC. Study of the dural sheaths allowed the authors to describe an original compartmentalization of the jugular foramen in 3 parts: 2 neural compartments-glossopharyngeal and vagal-and the interperiosteodural compartment. CONCLUSIONS In this dissection study, the existence of the EDNAC concept in the jugular foramen was demonstrated, leading to the proposal of a novel 3-part compartmentalization, challenging the classical 2-part compartmentalization, of the jugular foramen

Muscle Forehead Flap: a salvage surgery for closure of cutaneous fistula after cranioplasty exposure

Background Infection and skin fistula are well-known complications after cranioplasty leading to reconstruction exposure and usually requiring new surgical procedure with poor condition for cutaneous closure. We describe 2 cases using muscle forehead flap (MFF) to treat skin fistula and cranioplasty exposure. Case Description The first case was a 43-year-old man who underwent a calvarial bone graft of the frontal sinus anterior wall after craniofacial trauma. Three months postoperatively, osteitis of the bone reconstruction and a skin fistula occurred in the median frontal region. The second case was a 37-year-old woman treated for a cingular glioblastoma by 3 surgeries, concomitant chemoradiation therapy, and frontal reconstruction using a titanium plate. She presented a plate exposure associated with cerebrospinal fluid leak and meningitis. Both patients were successfully treated by surgical removal of the frontal cranioplasty and skin closure using MFF. We observed a satisfying cosmetic result with no recurrence of infection or fistula at 12 and 4 months, respectively. Conclusions MFF is a surgical option to treat complex cases of cutaneous fistula secondary to cranioplasty exposure of the anterior cranial fossa

Building connectomes using diffusion MRI: why, how and but

Why has diffusion MRI become a principal modality for mapping connectomes in vivo? How do different image acquisition parameters, fiber tracking algorithms and other methodological choices affect connectome estimation? What are the main factors that dictate the success and failure of connectome reconstruction? These are some of the key questions that we aim to address in this review. We provide an overview of the key methods that can be used to estimate the nodes and edges of macroscale connectomes, and we discuss open problems and inherent limitations. We argue that diffusion MRI-based connectome mapping methods are still in their infancy and caution against blind application of deep white matter tractography due to the challenges inherent to connectome reconstruction. We review a number of studies that provide evidence of useful microstructural and network properties that can be extracted in various independent and biologically-relevant contexts. Finally, we highlight some of the key deficiencies of current macroscale connectome mapping methodologies and motivate future developments

Evaluation des fonctions exécutives chez le sujet très âgé à partir de la cohorte Fibratlas.

International audienc

Arcuate foramen: "Anatomical variation shape or adaptation legacy?"

The groove of the vertebral artery on the posterior arch of the atlas (sulcus arteriae vertebralis) may become a complete or partial osseous foramen: the arcuate foramen. The presence of a complete or partial arcuate foramen is a rare anatomical variant described in a minority of patients and it seems to be associated with vertigo, vertebro-basilar insufficiency, posterior circulation strokes, and musculoskeletal pain. As the number and morphology of cervical vertebrae is highly preserved, we questioned about its significance from an evolutionary point of view. We thus investigated through an extensive literature review if the arcuate foramen is a pure anatomical variation shape or if it might represent an adaptation legacy. We observed five atlas of an extinct species, the Late Pleistocene Mammoths (M. primigenius), and we compared them with five atlas of a closely related existent species, the African elephant (L. africana). All the mammoths' atlas had an arcuate foramen through which the vertebral artery passed before turning anteriorly and becoming intradural. This foramen was not present in elephants' atlas, where only a groove was observed, such as in the majority of patients. We would like to raise the hypothesis that this peculiar morphology of mammoths' atlas might have contributed, in association with other factors, to their precocious extinction and that the arcuate foramen might represent a disadvantage in the evolutionary process, with a low prevalence in humans being the result of a natural selection

Spinal metastases in multiple myeloma: A high-risk subgroup for ISS III patients.

Patients with multiple myeloma (MM) have an extremely heterogeneous prognosis. The International Staging System (ISS) is actually the most reliable staging system and chromosomal abnormalities were integrated in the Revised-ISS. We wanted to evaluate the prognostic value of spinal secondary localization in patients with MM and its impact on the ISS. Epidemiological and biological data, as well as treatment protocols and secondary localization were analyzed for 650 consecutive patients diagnosed with MM from January 2006 to January 2017. The overall survival (OS) was dependent on the WHO performance status, ISS and Salmon and Durie stage at diagnosis. Furthermore, presence of spinal metastases at diagnosis was predictive of a worse outcome (p < 0.0001), while presence of peripheral bone metastases was not. Spinal metastases had a significant impact on OS for ISS III patients (p < 0.0001). Also, a history of bone marrow graft was associated with a better OS (p < 0.0001), while radiotherapy had no significant impact. The multivariate analysis confirmed that the spinal metastases at diagnosis determined a high-risk subgroup for ISS III patients with a very poor OS (p < 0.0001). Spinal metastases are a negative prognostic factor for patients with MM, especially for ISS III patients, and are associated with a shorter OS. Spinal metastasis should be systemically searched for and should be included in a modified staging system to better manage these patients

Variable-density k-space filling curves for accelerated Magnetic Resonance Imaging

Reducing scan times in magnetic resonance imaging (MRI) is essential for attaining high spatial resolution, which could aid in diagnosing certain pathologies, such as Alzheimer's disease. Methods to accelerate the time of segmented MR acquisitions commonly rely on simple sampling patterns such as straight lines, spirals or slight variations of these elementary shapes. However, such geometrical approaches do not take full advantage of the degrees of freedom offered by the hardware and cannot be easily adapted to fit an arbitrary sampling distribution. Here, we report the use of a versatile method inspired from stippling techniques that automatically generates optimized sampling patterns compatible with MR hardware constraints on maximum gradient amplitude and slew rate. These non-Cartesian sampling curves are designed to comply with key criteria for optimal sampling: a controlled distribution of samples and a locally uniform k-space coverage. Combining sampling efficiency with compressed sensing, the resulting sampling patterns allowed up to 20-fold reductions in MR scan time (compared to fully-sampled Cartesian acquisitions) for two-dimensional T * 2-weighted imaging without deterioration of image quality, as demonstrated by our experimental results at 7 Tesla on in vivo human brains for a high in-plane resolution of 390 µm. In comparison to existing non-Cartesian sampling strategies (spiral and radial), the proposed technique also yielded superior image quality. Since our method does not involve additional hardware, this approach offers a cost-free solution that has the potential to improve sampling efficiency in many MRI applications

Endoscopic Interhemispheric Disconnection for Intractable Multifocal Epilepsy: Surgical Technique and Functional Neuroanatomy.

Callosotomy represents a palliative procedure for intractable multifocal epilepsy. The extent of callosotomy and the benefits of adding anterior and posterior commissurotomy are debated. To describe a new technique of a purely endoscopic procedure to disconnect the corpus callosum, the anterior, posterior, and habenular commissures through the use of a single burr hole via a transfrontal transventricular route. Our surgical series was retrospectively reviewed in terms of seizure control (Engel's class) and complication rate. Five cadaveric specimens were used to demonstrate the surgical anatomy of commissural fibers and third ventricle. The procedure may be divided into 3 steps: (1) endoscopic transventricular transforaminal anterior commissure disconnection; (2) disconnection of posterior and habenular commissures; and (3) total callosotomy. Fifty-seven patients were included in the analysis. A favorable outcome in terms of epilepsy control (Engel class 1 to 3) was found in 71.4% of patients undergoing callosotomy coupled with anterior, posterior, and habenular commissure disconnection against 53% of patients with isolated callosotomy (P = .26). Patients with drop attacks had better epilepsy outcome independently from the surgical procedure used. The full endoscopic callosotomy coupled with disconnection of anterior, posterior and habenular commissures is a safe alternative to treat multifocal refractory epilepsy. A gain in seizure outcome might be present in this cohort of patients treated with total interhemispheric disconnection when compared with isolated callosotomy. Larger studies are required to confirm these findings