Seasonal Variations in Macrophages/Microglia Underlie Changes in the Mouse Model of Multiple Sclerosis Severity.

Both immune and neurodegenerative mechanisms underlie multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE). MS/EAE are triggered by encephalitogenic immune cells, including Th1 and Th17 cells, whereas T regulatory (Treg) cells are involved in inflammation resolution. Pro-inflammatory macrophages/microglia also play a deleterious role in the disease. Seasonal variations in MS relapses, active lesions, and pro- and anti-inflammatory cytokine levels have been described in MS patients and have been related with both perinatal and adult exposure to sunlight and other environmental factors. However, some data in EAE mice suggest that these variations might be, at least partially, endogenously determined. Thus, our objective was to study the effect of the season of birth and disease induction on the course of EAE, and immune cell infiltration in the central nervous system (CNS) in myelin oligodendrocyte glycoprotein (MOG35-55)-induced EAE in 8 weeks old, female C57BL/6N mice maintained under constant, controlled conditions. EAE severity as well as pathogenic (Th1, Th17, macrophages/microglia) and protective (Treg) subsets was found to vary according to the season of birth or of EAE induction. Summer-born or summer-immunized animals developed a milder disease, which coincided with variations in numbers of T effector/regulatory subsets, and significantly low numbers of macrophages/microglia. These results suggest that endogenous rhythms in immune responses might cause seasonal variations in EAE severity, and, maybe, in the course of MS, and that they might be related to macrophages/microglia.

Modified "Extended" Suboccipital Subtonsillar Clipping of a Ruptured Proximal Pica Aneurysm: Technical Note with Relevant Anatomical Demonstration.

BACKGROUND AND IMPORTANCE: Lesions located lateral to the lower brainstem, such as proximal posterior inferior cerebellar artery (PICA) aneurysms, are surgically challenging. We report a case of a patient with a left proximal PICA aneurysm that was successfully clipped via a so-called "extended" suboccipital subtonsillar approach, which allowed us to obtain proper vascular control without removal of the atlas. The anatomy relevant for this approach has been studied. METHODS: Three adult cadaveric heads were studied. The relevant neurovascular anatomy related to this approach was exposed. Hence, this technique was applied on the patient herewith reported. CASE PRESENTATION: A 60-year-old man with sudden onset of severe headache, nausea, and vomiting was admitted to our hospital. Computed tomography of the brain showed diffuse subarachnoid hemorrhage, mainly distributed at the level of the perimesencephalic cisterns. Cerebral angiography revealed a 3-mm aneurysm arising at the origin of the left PICA. The aneurysm was considered unsuitable for coil embolization, so it was treated via a "modified" posterolateral suboccipital subtonsillar route. The modification consisted of accomplishing proper proximal vascular control at the extracranial segment of the vertebral artery (V3), without the need of further removal of the posterior portion of the atlas. The patient was discharged neurologically intact. CONCLUSIONS: The technique we suggested allowed no unnecessary removal of bone, with no need to drill the occipital condyle or remove the atlas, offered proper proximal vascular control in the early stage of the surgical procedure, and limited the quantity of temporary vascular clips inside the intracranial surgical field.

Postoperative epidural hematoma contributes to delayed upper cord tethering after decompression of Chiari malformation type I.

BACKGROUND: Symptomatic arachnoiditis after posterior fossa surgical procedures such as decompression of Chiari malformation is a possible complication. Clinical presentation is generally insidious and delayed by months or years. It causes disturbances in the normal flow of cerebrospinal fluid and enlargement of a syrinx cavity in the upper spinal cord. Surgical de-tethering has favorable results with progressive collapse of the syrinx and relief of the associated symptoms. CASE DESCRIPTION: A 30-year-old male with Chiari malformation type I was treated by performing posterior fossa bone decompression, dura opening and closure with a suturable bovine pericardium dural graft. Postoperative period was uneventful until the fifth day in which the patient suffered intense headache and progressive loose of consciousness caused by an acute posterior fossa epidural hematoma. It was quickly removed with complete clinical recovering. One year later, the patient experienced progressive worsened of his symptoms. Upper spinal cord tethering was diagnosed and a new surgery for debridement was required. CONCLUSIONS: The epidural hematoma compressing the dural graft against the neural structures contributes to the upper spinal cord tethering and represents a nondescribed cause of postoperative fibrosis, adhesion formation, and subsequent recurrent hindbrain compression.

Spinal cord lipoma without dysraphism in the infancy that extends intracranially. Case report and review of the literature.

BACKGROUND: Spinal intramedullary lipoma extending to the posterior fossa is very rare in children. We made a revision of the literature and report the diverse opinions and surgical procedures. CASE DESCRIPTION: We report the case of a 16-month-old male infant who was operated on in the Pediatric Neurosurgical Unit of our hospital; his clinical and surgical outcome are related. CONCLUSION: Intramedullary lipoma of the spinal cord with intracranial extension in infancy is a very rare pathology reported in the literature. Our patient was treated with decompression and subtotal removal; he had a critical postoperative course but was recovering slowly after that. Most authors prefer incomplete resection because these lesions do not have a clear-cut margin. Another neurosurgeon performed a decompression only, without resection. Some authors performed the surgical treatment before symptom progression. Another surgeon reported that the surgical indication is debatable when the neurologic manifestations are poor or absent. The surgical indication and the strategy for treatment are controversial and they depend on the clinical situations of the patients.