The modified retrosigmoid approach: a how I do it

BACKGROUND: The traditional retrosigmoid (RS) approach provides limited exposure of the inferior compartment of the CPA, while radical skull base approaches are demanding and associated with significant morbidity. METHODS: This study outlines the relevant surgical anatomy and the different surgical steps of a modified retrosigmoid (MRS) approach. RESULTS: The MRS provides enhanced exposure of the CPA and deep vascular structures resulting from a modified RS craniotomy and limited exposure of the sigmoid sinus. CONCLUSION: In selected posterior fossa lesions, this cisternal approach is a straightforward corridor that can be routinely performed as a safe alternative to radical cranial base approaches

Toward the development of 3-dimensional virtual-reality video tutorials in the French neurosurgical residency program

BACKGROUND: The present study developed 3D video tutorials with commentaries, using virtual-reality headsets (VRH). VRHs allow 3D visualization of complex anatomy from the surgeon\u27s point of view. Students can view the surgery repeatedly without missing the essential steps, simultaneously receiving advice from a group of experts in the field. METHODS: A single-center prospective study assessed surgical teaching using 3D video tutorials designed for French neurosurgery and ENT residents participating in the neuro-otology lateral skull-base workshop of the French College of Neurosurgery. At the end of the session, students filled out an evaluation form with 5-point Likert scale to assess the teaching and the positive and negative points of this teaching tool. RESULTS: 22 residents in neurosurgery (n=17, 81.0%) and ENT (n=5) were included. 18 felt that the 3D video enhanced their understanding of the surgical approach (81.8 %). 15 (68.2%) thought the video provided good 3D visualization of anatomical structures and 20 that it enabled better understanding of anatomical relationships (90.9%). Most students had positive feelings about ease of use and their experience of the 3D video tutorial (n=14, 63.6%). 20 (90.9%) enjoyed using the video. 12 (54.5%) considered that the cadaver dissection workshop was more instructive. CONCLUSIONS: 3D video via a virtual reality headset is an innovative teaching tool, approved by the students themselves. A future study should evaluate its long-term contribution, so as to determine its role in specialized neurosurgery and ENT diploma courses

Predictive Factors of Poor Prognosis After Surgical Management of Traumatic Acute Subdural Hematomas: A Single-Center Series

BACKGROUND: Traumatic acute subdural hematomas (ASDHs) showed the highest mortality of intracranial hematomas. The aim of the current study was to identify predictive factors of poor prognosis among patients who were operated on. METHODS: This is a single-center retrospective cohort study of 82 patients who underwent surgical evacuation of a traumatic ASDH between January 2009 and December 2016. The epidemiologic, clinical, radiologic, and surgical features were recorded. Postoperative outcome were assessed by the Glasgow Outcome Scale (GOS) score at 6 months. Univariate and multivariate analysis and a classification and regression tree (CART) were performed. RESULTS: At 6 months, 76% of patients achieved an unfavorable outcome (GOS score 1-3). The context of polytrauma (P = 0.03) and ASDH thickness ≥20 mm (P = 0.02) were significantly associated with poor outcome in the multivariate analysis. The CART algorithm isolated 3 subgroups of patients with an unfavorable prognosis: polytrauma (91%), isolated head injury (HI) featuring an ASDH thickness ≥20 mm (89%), or isolated HI featuring a thickness <20 mm in a patient older than 54 years (71%). Isolated patients with HI younger than 54 years harboring an ASDH <20 mm thick had the most promising results, with 53% with a GOS score of 4 or 5. CONCLUSIONS: The context of polytrauma, ASDH thickness, and age were major predictive factors of poor prognosis in patients with surgically evacuated traumatic ASDH. The CART algorithm using these features isolated subgroups with decreasingly unfavorable outcome, providing a relevant statistical tool to apply to future studies of traumatic ASDH

Stereoscopic Surgical Video of Combined Petrosectomy With Virtual Reality Headset: 3-Dimensional Operative Video

The use of 3-dimensional (3D) videos allows students to visualize surgical procedures from the perspective of the surgeon without missing the essential parts.1 This 3D commented video demonstrates the operative technique and surgical nuances of the combined petrosectomy, visualize using virtual reality headsets. Historically, traditional intradural cisternal routes using suboccipital and pterional approaches have been proposed to remove petroclival tumors.2-5 It allows rapid identification of neurovascular structures and a short exposure time. However, access to the petroclival region is far, not direct, and requires intradural cerebral retraction.6 In order to improve the access for tumoral dissection, lateral transpetrosal approaches have been proposed.7-12 The extradural route shortened the distance to the petroclival region, allows to better preserve the veins, to decrease the cerebral retraction, to interrupt early the tumor vascular supply, and a larger extent of resection.6 Transpetrosal approaches includes middle fossa approach8,10 (removing the petrous apex), posterior petrosal approach9,13,14 (removing of presigmoid retrolabyrinthine bone), and translabyrinthine petrosectomy.12 A combined petrosectomy may be used to approach larger tumor extending across the clival midline, upward to the tentorium or downward to the lower cranial nerves.6,10,15,16 Alternatively, according to Nanda, a retro-sigmoid approach may need to be performed to avoid critical draining veins injury.10,17 Good resection and outcomes are obtained when experienced surgeons use familiar approaches and microsurgical techniques.1

Long term surgical results of 154 petroclival meningiomas: A retrospective multicenter study

BACKGROUND: Outcomes of petroclival meningiomas (PCM) (morbidity, permanent cranial nerves deficit, tumor removal and recurrence) are inconsistent in the literature, making it a challenge to predict surgical morbidity. METHODS: A multicenter study of patients with PCMs larger than 2.5cm between 1984 and 2017 was conducted. The authors retrospectively reviewed the patients\u27 medical records, imaging studies and pathology reports to analyze presentation, surgical approach, neurological outcomes, complications, recurrence rates and predictive factors. RESULTS: There were 154 patients. The follow-up was 76.8 months on average (range 8-380 months). Gross total resection (GTR) was achieved in 40 (26.0%) patients, subtotal resection (STR) in 101 (65.6%), and partial resection in 13 (8.3%). Six (2.6%) perioperative deaths occurred. The 5-year, 10-year and 15-year progression-free survival (PFS) of GTR and STR with radiation therapy (RT) was similar (100%, 90% and 75%). PFS of STR without adjuvant radiation was associated with progression in 71%, 51% and 31%, respectively. Anterior petrosectomy and combined petrosectomy were associated with higher postoperative CN V and CN VI deficits compared to the retrosigmoid approach. The latter had a significantly higher risk of CN VII, CN VIII and LCN deficit. Temporal lobe dysfunction (seizure and aphasia) were significantly associated with the anterior petrosectomy approach. CONCLUSIONS: Our study shows that optimal subtotal resection of PCMs associated with postoperative RT or stereotactic radiosurgery results in long-term tumor control to equivalent radical surgery. Case selection and appropriate intraoperative judgement are required to reduce the morbidity

Charged pion form factor between Q^2=0.60 and 2.45 GeV^2. II. Determination of, and results for, the pion form factor

The charged pion form factor, Fpi(Q^2), is an important quantity which can be used to advance our knowledge of hadronic structure. However, the extraction of Fpi from data requires a model of the 1H(e,e'pi+)n reaction, and thus is inherently model dependent. Therefore, a detailed description of the extraction of the charged pion form factor from electroproduction data obtained recently at Jefferson Lab is presented, with particular focus given to the dominant uncertainties in this procedure. Results for Fpi are presented for Q^2=0.60-2.45 GeV^2. Above Q^2=1.5 GeV^2, the Fpi values are systematically below the monopole parameterization that describes the low Q^2 data used to determine the pion charge radius. The pion form factor can be calculated in a wide variety of theoretical approaches, and the experimental results are compared to a number of calculations. This comparison is helpful in understanding the role of soft versus hard contributions to hadronic structure in the intermediate Q^2 regime.Comment: 18 pages, 11 figure

Whole-genome sequencing reveals host factors underlying critical COVID-19

Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease

Burnout et santé au travail en neurochirurgie : Prévalence et facteurs associés

National audienc

Rupture limit evaluation of human cerebral aneurysms wall: Experimental study

International audienceBACKGROUND AND PURPOSE: Rupture risk of intracranial aneurysms is a major issue for public healthcare. A way to obtain an individual rupture risk assessment is a main objective of many research teams in the world. For many years, we have investigated the relationship between the mechanical properties of aneurysm wall tissues and the rupture risk. In this work, we try to go further and investigate rupture limit values.METHODS: Following surgical clipping, a specific conservation protocol was applied to aneurysmal tissues in order to preserve their mechanical properties. Thirty-nine intracranial aneurysms (27 females, 12 males) were tested using a uniaxial tensile test machine under physiological conditions, temperature, and saline isotonic solution. These represented 24 unruptured and 15 ruptured aneurysms. Stress/strain curves were then obtained for each sample, and a fitting algorithm was applied following a Yeoh hyperelastic model with 2 parameters. Moreover, uniaxial tensile tests were conducted until rupture of samples to obtain values of stress and strain rupture limit.RESULTS: The significant parameter a C2 of the hyperelastic Yeoh model, allowed us to classify samples' rigidity following the terminology we adopted in previous papers (Costalat et al., 2011; Sanchez et al., 2013): Soft, Stiff and Intermediate. Moreover, strain/stress rupture limit values were gathered and analyzed thanks to the tissue rigidity, the status of the aneurysm (initially ruptured or unruptured) and the gender of the patient.CONCLUSION: Strain rupture limit was found quite stable around 20% and seems not to be correlated with the status of the aneurysm (initially ruptured or unruptured), neither with the gender of the patient. However, stretch and stress rupture limit seems not to be independent on the rigidity. The study confirms that ruptured aneurysms mainly present a soft tissue and unruptured aneurysms present a stiff material

Bronchial mucosal manifestations of atopy: a comparison of markers of inflammation between atopic asthmatics, atopic nonasthmatics and healthy controls

We studied the role of atopy, as defined by positive skin tests to common inhalant allergens, in allergic bronchial inflammation. Endobronchial biopsies were taken via the fibreoptic bronchoscope in 13 symptomatic atopic asthmatics, 10 atopic nonasthmatics, and 7 normals. The numbers of mast cells, identified in the submucosa by immunohistochemistry using the AA1 monoclonal antibody against tryptase, were no different between the three groups, but electron microscopy showed that mast cell degranulation, although less marked in atopic nonasthmatics, was a feature of atopy in general. The numbers of eosinophils, identified by immunohistochemical staining using the monoclonal anti-eosinophil cationic protein antibody, EG2, were greatest in the asthmatics, low or absent in the normals and intermediate in the atopic nonasthmatics. In both atopic groups eosinophils showed ultrastructural features of degranulation. Measurements of subepithelial basement membrane thickness on electron micrographs showed that the collagen layer was thickest in the asthmatics, intermediate in the atopic nonasthmatics and thinnest in the normals. The results suggest that airways eosinophilia and degranulation of eosinophils and mast cells, as well as increased subepithelial collagen deposition, are a feature of atopy in general and suggest that the degree of change may determine the clinical expression of this immune disorder