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

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.

A Comprehensive Training Model for Simulation of Intracranial Aneurysm Surgery Using a Human Placenta and a Cadaveric Head.

BACKGROUND AND OBJECTIVES: Aneurysmal surgery is technically complex, and surgeon experience is an important factor in therapeutic success, but training young vascular neurosurgeons has become a complex paradigm. Despite new technologies and simulation models, cadaveric studies still offer an incomparable training tool with perfect anatomic accuracy, especially in neurosurgery. The use of human placenta for learning and improving microsurgical skills has been previously described. In this article, we present a comprehensive simulation model with both realistic craniotomy exposure and vascular handling consisting of a previously prepared and perfused human placenta encased in a human cadaveric specimen. METHODS: Humans' placentas from the maternity and cadaveric heads from the body donation program of the anatomy laboratory were used. Placentas were prepared according to the established protocol, and aneurysms were created by catheterization of a placental artery. Ten participants, including senior residents or young attendees, completed an evaluation questionnaire after completing the simulation of conventional unruptured middle artery aneurysm clipping surgery from opening to closure. RESULTS: The skin incision, muscle dissection, and craniotomy were assessed as very similar to reality. Brain tissue emulation and dissection of the lateral fissure were judged to be less realistic. Vascular management was evaluated as similar to reality as closure. Participants uniformly agreed that this method could be implemented as a standard part of their training. CONCLUSION: This model could provide a good model for unruptured aneurysm clipping training.

Endoscopic Transfontanellar Approach of a Cyst Anterior to the Brainstem Crossing the Foramen Magnum-Part II: Success of Multiple Fenestrations: Two-Dimensional Operative Video.

Premature infants with severe germinal matrix/intraventricular hemorrhage are at high risk of posthemorrhagic ventricular dilation and hydrocephalus (Video 1). We report a 4-month-old premature infant with grade III intraventricular hemorrhage and compartmentalized hydrocephalus with an unusual craniospinal cyst. The cyst extended anteriorly from the mesencephalon to the posterior wall of C6, causing severe compression of the brainstem and spinal cord. An endoscopic procedure was performed first to achieve a unique cranial fenestration, which is detailed in "Endoscopic Transfontanellar Approach of a Cyst Anterior to the Brainstem Crossing the Foramen Magnum-Part I: Failure of Unique Fenestration." One month later the clinical picture recurred. Magnetic resonance imaging revealed hydrocephalus and cyst recurrence. A second procedure with endoscopic fenestration and shunt revision was needed. The same right transfontanellar approach was chosen, using a straight 30° endoscope. The procedure and surgical technique are explained in a step-by-step fashion. Extreme care was taken to align the head and the cervical spine. This allowed access to the extreme caudal cyst membrane posterior to C6 to create multiple transfixing fenestrations of the cyst. At 18-month follow-up, the child demonstrated almost normal neurological and psychomotor development with no cyst recurrence or hydrocephalus. Our report underlines the importance of performing multiple fenestrations of such cysts. We believe that performing a transfixing fenestration through the cyst allows cerebrospinal fluid flow and prevents recurrence, as, for instance, has been shown for suprasellar arachnoid cysts.

Endoscopic Transfontanellar Approach of a Cyst Anterior to the Brainstem Crossing the Foramen Magnum-Part I: Failure of Unique Fenestration: 2-Dimensional Operative Video.

Premature infants with severe germinal matrix intraventricular hemorrhage (IVH) are at high risk of posthemorrhagic ventricular dilation and hydrocephalus (Video 1). We report the case of a 3-month-old premature infant referred for posthemorrhagic multilocated hydrocephalus. He presented with somnolence, hypotonia, and a bulging fontanelle. His past medical history included an IVH grade III with hydrocephalus initially treated by temporary ventriculosubgaleal shunting. Magnetic resonance imaging (MRI) showed persistent hydrocephalus associated to a cyst extending anteriorly from the mesencephalon to the posterior wall of the sixth cervical vertebra, causing severe brainstem and spinal cord compression. A two-step surgery was performed, consisting of an endoscopic procedure and a ventriculo peritoneal shunt placement, to achieve hydrocephalus treatment and cyst fenestration. A right transfontanellar approach with the head flexed was chosen, using a straight 30-degree endoscope. The procedure and surgical technique are explained in a step-by-step fashion in the original conditions. A large unique fenestration was performed with no postoperative complications and improvement of the neurological status. One month later the patient presented again with symptomatic intracranial hypertension with compatible clinical and imagery findings. MRI showed cyst recurrence and hydrocephalus. We therefore revised our strategy and performed an additional procedure, which is detailed in the second part of the video (Part II: Success of Multiple Fenestrations). Our report underlines the high risk of recurrence of such cysts in post-hemorrhagic arachnoiditis. Cyst recurrence may be explained by the absence of crossing flow when a unique perforation is made.

Using Smartphones for Clinical Assessment in Cervical Spondylotic Myelopathy a Feasibility Study.

Degenerative cervical myelopathy (DCM) is characterized by a progressive deterioration in spinal cord function. Its evaluation requires subjective clinical examination with wide interobserver variability. Objective quantification of spinal cord function remains imprecise, even though validated myelopathy-grading scales have emerged and are now widely used. We created a Smartphone Application, the N-Outcome App, with the aim of quantifying accurately and reliably spinal cord dysfunction using a 5-minute Test. A patient suffering from DCM was clinically evaluated before surgery, at 3 and 6 months follow-up after surgical decompression of the cervical spinal cord. Standard scores (Nurick grade, modified Japanese Orthopedic Association (mJOA) score) were documented at these time points. A 5-minute motor and proprioceptive performance test aided by a smartphone with the N-outcome App was also performed. Motor performance in rapid alternating movements and finger tapping improved in correlation with improvements in standard grading scale scores. Clinical improvements were seen in maximum reflex acceleration and in Romberg testing which showed less closed/open eyes variation, suggesting pyramidal and proprioceptive function recovery. We demonstrate that using the N-Outcome App as an adjunct to clinical evaluation of compressive myelopathy is feasible and potentially useful. The results correlate with the results of clinical assessment obtained by standard validated myelopathy scores.

Rate of Rebleed and Retreatment of Previously Treated Intracranial Aneurysms.

BACKGROUND: Intracranial aneurysms (IAs) can be treated through endovascular treatment (EVT) or microsurgery (MS). Treated IAs can recanalize, which can lead to rupture or retreatment. OBJECTIVE: The aim of our study was to evaluate the natural history of previously treated IA, by evaluating the risk of rupture and the risk of retreatment. METHODS: All patients treated for an IA between 2007 and 2017 in 4 hospitals were included. The rate of (recurrent) hemorrhage and the rate of prophylactic retreatment were retrospectively evaluated. Kaplan-Meier survival analysis with log-rank tests was used to compare the rates of rupture or retreatment. Patients with ruptured and unruptured aneurysms were separated, and we compared the risk of retreatment between EVT and the surgical treatment. RESULTS: A total of 4997 IAs were included in the study, corresponding to 20,489 patient-years. Overall, 28 (0.6%) aneurysms that had been previously treated demonstrated hemorrhage. Moreover, 237 (4.7%) aneurysms were retreated for recanalization without hemorrhage. The rate of retreatment was higher in the EVT-treated IAs as compared with the MS-treated IAs (LogRank: P < 0.0001) and higher in the previously ruptured IAs versus unruptured IAs (LogRank: P < 0.0001). However, the rate of posttreatment hemorrhage/IA rupture was similar for both groups. CONCLUSIONS: The rate of IA retreatment is low; however, the rate of hemorrhage/rupture from treated IAs is even lower. A higher rate of retreatment was noted in EVT-treated IAs versus MS-treated IAs and in ruptured IAs versus unruptured IAs; however, the rate of hemorrhage or rerupture was comparable between the groups.

Importance of Fenestration Size for Definitive Treatment of a Quadrigeminal Arachnoid Cyst: Endoscopic Inspection of the Cyst and Surrounding Anatomy: 2-Dimensional Operative Video.

Arachnoid cysts are fluid-filled sacs, located between the brain or spinal cord and the arachnoid membrane. Their prevalence in children is between 1% and 3%. Quadrigeminal arachnoid cysts represent 1% to 10% of them and are often associated with hydrocephalus, mostly by an obstructive mechanism, explained by compression of the tectum of the midbrain. When an indication for treatment is retained, 3 surgical options are available: microsurgical excision/fenestration, endoscopic fenestration, and shunt placement. Endoscopic treatment is considered the best compromise of definitive treatment with least surgical morbidity, especially because quadrigeminal cysts are located close to the midline, in intimate relationships with basal cisterns and ventricles. We here present the endoscopic treatment of a prenatally diagnosed quadrigeminal arachnoid cyst type III1 with right lateral extension into the middle cerebral fossa, and associated hydrocephalus, treated at the age of 18 mo.Step-by-step detail of surgical technique is presented in original anatomic conditions. Restoration of better cerebrospinal fluid pathways being the objective of this surgery, ventriculocystic, and cyst-cisternal fenestrations were made. Secondary obstruction of the cyst occurred a few months later, requiring further endoscopic treatment to obtain a larger fenestration that allowed good long-term clinical and radiological outcome. The key point of this video is to compare the 2 procedures, stressing the importance of the dimension of fenestrations, to ensure a long-term patency of both stomas.The patient being a child, both parents gave their consent for publication and signed a form.

Stereoscopic Images from Computed Tomography Angiograms.

OBJECTIVE: To present an adaptation of the anaglyph photography technique to be used with radiological images from computed tomography angiograms, enabling stereoscopic visualization of a patient's individual abnormal vascular anatomy for teaching, case discussion, or surgical planning purposes. METHODS: Traditional anaglyph procedures with actual objects yield 2 independent photographs, simulating the image perceived by each eye. Production of anaglyphs from angiograms involve 3 basic procedures: volume rendering, image capture, and image fusion. Volume renderings were reconstructed using a free, open-source DICOM (Digital Imaging and Communications in Medicine) reader. Subsequently, the virtual object was positioned to mimic the operator's angle of view, and different perspectives of the reconstructed volume could be obtained through exclusively horizontal rotation. The 2 images were then fused after their color composition was modified so that each eye would perceive only 1 image when using anaglyph glasses. RESULTS: Forty-three angiograms were reviewed for the purpose of this study and a total of 6 examinations were selected for illustration of the technique. Stereoscopic display was possible for all of them and in the 3 types of support tested: computer monitor, tablet, and smartphone screens. CONCLUSIONS: Anaglyph display of computed tomography angiograms is an effective and low-cost alternative for the stereoscopic visualization of a patient's individual intracranial vascular anatomy.

Surgical Thrombectomy Combined with Bilateral Decompressive Craniectomy in a Life-Threatening Case of Coma from Cerebral Venous Sinus Thrombosis: Case Report and Literature Review.

BACKGROUND: Cerebral venous sinus thrombosis (CVST) is a rare cause of stroke. Medical and neurointerventional strategies, such as in situ thrombolysis, are standard therapies. These techniques are insufficient when clinical deterioration arises from mass-associated effects and transtentorial herniation; in such cases, decompressive hemicraniectomy may be indicated. To the best of our knowledge, the association of open surgical thrombectomy with bilateral decompressive craniectomy has not been reported to date. CASE DESCRIPTION: A 45-year-old woman presented with extensive cerebral venous sinus thrombosis that was resistant to anticoagulation and endovascular therapies. Her clinical condition deteriorated until she became comatose, and bilateral hemicraniectomy combined with open surgical thrombectomy through the superior sagittal sinus was indicated. Computed tomography angiography confirmed postoperative maintenance of sinus permeability. The patient's clinical status improved dramatically, and she had a favorable outcome, including recovery of her functional independence to perform all activities of daily living (modified Rankin Scale score = 0). The follow-up period was 5 years. CONCLUSIONS: Open surgical thrombectomy combined with decompressive craniectomy is a lifesaving procedure that can lead to favorable outcome and should be considered for treatment of refractory malignant cerebral venous sinus thrombosis.

Treating Cerebrospinal Fluid Rhinorrhea without Dura Repair: A Case Report of Posterior Fossa Choroid Plexus Papilloma and Review of the Literature.

BACKGROUND: Choroid plexus papilloma revealed by nontraumatic cerebrospinal fluid (CSF) rhinorrhea has only been described 5 times, to our knowledge, in the literature. The challenges in this situation are to recognize CSF leak, to rapidly understand the pathophysiology of the leak, and to choose the best treatment strategy in emergency. We report an original case of posterior fossa choroid plexus papilloma revealed by CSF leak. We then discuss the surgical strategy and the pathophysiology of CSF leak, which is explained, in this case, by both hyperproduction of CSF and local skull base erosion. CASE DESCRIPTION: We report the case of a 47-year-old man who has developed spontaneous rhinorrhea, right hearing loss, and confusion. A choroid plexus papilloma of the right cerebellomedullary cistern was diagnosed. Hydrocephalus and pneumocephalus were associated with an erosion of the homolateral skull base. The patient underwent surgical total tumor removal by a median suboccipital approach after implantation of a temporary external ventricular drainage. The patient recovered completely without any recurrence of CSF rhinorrhea. The 5-month postoperative images show total bone re-growth and resolution of hydrocephalus. CONCLUSIONS: Our case shows that 1) causal reasoning is of major importance when dealing with CSF rhinorrhea and that 2) dura repair can be avoided when treating CSF leak secondary to posterior fossa choroid plexus papilloma.