66 research outputs found
Is erythropoietin a worthy candidate for traumatic brain injury or are we heading the wrong way?
No full textTraumatic brain injury (TBI) is a leading cause of death and disability in the modern society. Although primary prevention is the only strategy that can counteract the primary brain damage, numerous preclinical studies have been accumulated in order to find therapeutic strategies against the secondary damage. In this scenario erythropoietin (EPO) has been shown to be a promising candidate as neuroprotective agent. A recent clinical trial, however, has shown that EPO has not an overall effect on outcomes following TBI thus renewing old concerns. However, the results of a prespecified sensitivity analysis indicate that the effect of EPO on mortality remains still unclear. In the light of these observations, further investigations are needed to resolve doubts on EPO effectiveness in order to provide a more solid base for tailoring conclusive clinical trials
Multimodal Intraoperative Neuromonitoring in Aneurysm Surgery
No full textFollowing aneurysmal subarachnoid hemorrhage, the primary goal of treatment is to exclude the vascular malformation from the intracranial circulation, while preserving the parent artery. In unruptured aneurysms, the decision whether to treat or observe the malformation is made on a case-by-case basis. In this regard, the ISUIA (International Study of Unruptured Intracranial Aneurysms) investigators suggested that aneurysm size and location were independent predictors for aneurysm rupture.1 ISUIA examined 1692 patients with cerebral aneurysms with a mean follow-up time of 4.1 years. Rupture rates differed depending on size and location, ranging from 0% in aneurysms <7 mm located in the internal carotid artery, anterior circulation, or middle cerebral artery to up to 50% in aneurysms >25 mm located in the posterior circulation. More recently, UCAS (Unruptured Cerebral Aneurysm Study) reported results similar to ISUIA. However, other evidence has contradicted these studies, with a higher percentage of small aneurysms reported among case series of ruptured intracranial aneurysms. This indicates a discrepancy between the ISUIA and UCAS data and the size of ruptured aneurysms seen in routine clinical practice
Calcified Spinal Meningioma: A Lurking Danger
No full textTumors of the spine with an intradural location have an incidence ranging from 3 to 10 per 100,000 persons per year, and intradural extramedullary tumors account for two thirds of all intraspinal neoplasms. Among these, spinal meningiomas account for 25%–46% of all spinal cord tumors. They develop from the arachnoid cells that differentiate from neural crest cells and, like cerebral meningioma, they have a slow-growing behavior. Although spinal meningiomas are not uncommon, calcified spinal meningioma is rare in spinal location. Calcified meningioma manifests with extensive matrix and tends to infiltrate the surrounding structures. It exhibits a growth pattern limited by an incompletely developed intermediate leptomeningeal layer. This pattern makes such a tumor different from the commonly encountered meningioma that develops into a variable interface in the small space confined between the arachnoid and the intermediate leptomeningeal spaces. Because the intraspinal spaces are much smaller than intracranial spaces, symptoms usually appear rapidly compared with intracranial tumors
The Pathogenetic Mechanisms of intratumoral hemorrhage in meningioma: The role of microvascular differentiation
No full textThe transformation of normal cells into neoplastic cells is based on a series of gradual and progressive processes . One of the most important aspects underlying the tumorigenesis ist hat neoplastic proliferation needs mechanisms to ensure cancer development, bypass the body's protective strategies, and survive the apoptotic mechanisms. Subsequently, measures to promote replicative immortality and vascular support will be required. If cancer develops in an area offering excellent vascularization, pre-existing vascular circuits can supporti ts growth .Otherwise,tumor
angiogenetic mechanisms will trigger new vascular networks, which will be necessary for tumor survival and expansion. The latter occurrence is what takes place in most of the neoplasms characterized by high growth pattern: proangiogenic factors secreted by the tumor, the most
important being the vascular endothelial growth factor (VEGF), create a chemotactic gradient able to recruit endothelial cells and pericytes from the existing vascular system
Introducing the concept of âCSF-shift edemaâ in traumatic brain injury
No full textBrain edema after severe traumatic brain injury (TBI) plays an important role in the outcome and survival of injured patients. It is also one of the main targets in the therapeutic approach in the current clinical practice. To date, the pathophysiology of traumatic brain swelling is complex and, being that it is thought to be mainly cytotoxic and vasogenic in origin, not yet entirely understood. However, based on new understandings of the hydrodynamic aspects of cerebrospinal fluid (CSF), an additional mechanism of brain swelling can be considered. An increase in pressure into the subarachnoid space, secondary to traumatic subarachnoid hemorrhage, would result in a rapid shift of CSF from the cisterns, through the paravascular spaces, into the brain, resulting in an increase of brain water content. This mechanism of brain swelling would be termed as “CSF-shift edema.”. This “CSF-shift,” promoted by a pressure gradient, leads to increased pressure inside the paravascular spaces and the interstitium of the brain, disturbing the functions of the paravascular system, with implications of secondary brain injury. Cisternostomy, an emerging surgical treatment, would reverse the direction of the CSF-shift, allowing for a decrease in brain swelling. In addition, this technique would reduce the pressure in the paravascular spaces and interstitium, leading to a recovery of the functionality of the paravascular system. © 2017 Wiley Periodicals, Inc
Update on Novel CCM Gene Mutations in Patients with Cerebral Cavernous Malforzmations
No full textCerebral cavernous malformations (CCMs) are lesions affecting brain microvessels. The pathogenesis is not clearly understood. Conventional classification criterion is based on genetics, and thus, familial and sporadic forms can be distinguished; however, classification of sporadic cases with multiple lesions still remains uncertain. To date, three CCM causative genes have been identified: CCM1/KRIT1, CCM2/MGC4607 and CCM3/PDCD10. In our previous mutation screening, performed in a cohort of 95 Italian patients, with both sporadic and familial cases, we identified several mutations in CCM genes. This study represents further molecular screening in a cohort of 19 Italian patients enrolled by us in the few last years and classified into familial, sporadic and sporadic with multiple lesions cases. Direct sequencing and multiplex ligation-dependent probe amplification (MLPA) analysis were performed to detect point mutations and large genomic rearrangements, respectively. Effects of detected mutations and single-nucleotide polymorphisms (SNPs) were evaluated by an in silico approach and by western blot analysis. A novel nonsense mutation in CCM1 and a novel missense mutation in CCM2 were detected; moreover, several CCM2 gene polymorphisms in sporadic CCM patients were reported. We believe that these data enrich the mutation spectrum of CCM genes, which is useful for genetic counselling to identify both familial and sporadic CCM cases, as early as possible
Glossopharyngeal neuralgia caused by a complex neurovascular conflict: Case report and review of the literature
No full textBACKGROUND:
Glossopharyngeal neuralgia (GN) is a rare condition characterized by severe, paroxysmal episodes of pain mainly localized to the external ear canal, pharynx, and tongue, usually caused by a neurovascular conflict between postero-inferior cerebellar artery (PICA) and IX cranial nerve. Sometimes there is also a compression of X c.n.
CASE DESCRIPTION:
We present a case of a 71-year-old female with a 3-year history of intense pain localized in the pharynx and posterior portion of the tongue. Preoperative magnetic resonance imaging (MRI) documented a neurovascular conflict between a loop of PICA and IX left c.n. Surgery was performed through a retrosigmoid craniectomy. The intraoperative findings documented a loop of PICA compressing IX, X, and XI c.n. Microvascular decompression (MVD) of IX c.n. was performed using the interposing technique. No rhizotomy and MVD of the X c.n. was performed. Postoperative course showed the regression of all symptoms.
CONCLUSIONS:
The surgical treatment of patients with GN caused by complex neurovascular conflicts can be safely performed with the classical MVD of IX c.n. A double MVD of both IX and X c.n. has a role only in patients presenting symptoms from both nerves. Rhizotomy, in our opinion, has to be avoided in all cases. The authors review the literature concerning GN caused by complex neurovascular conflicts
Navigated Brain Stimulation (NBS) for pre-surgicalplanning of brain tumors
No full textPreoperative cortical mapping is increasingly recogni-zed as a fundamental procedure for better planning thesurgical treatment of brain tumors. Brain mapping hel-ps the definition of skull opening, access route, andextent of tumor resection. Brain tumors can actuallydistort the normal functional anatomy of the cortex bydisplacing functional areas or inducing its plastic chan-ge. When this occurs in the area of the motor cortex,preoperative mapping of this functional area is impera-tive to minimize the risk of damaging motor function bysurgical intervention.Different technologies are currently available to per-form a pre-operative identification of functional brainareas. Functional magnetic resonance imaging (fMRI) isprobably the most commonly used technique. It worksby indirectly measuring metabolic (brain oxygen level)changes during a specific task. Positron emission tomo-graphy (PET likewise measures cerebral blood flow,oxygen or glucose consumption of brain areas duringpatient performance of tasks. Bot PET and fMRI have agood spatial resolution, but a low temporal resolutionand brain tumors may cause metabolic changes thatmay blur the identification of functional hypermetabo-lic areas. Electroencephalography has also been usedfor preoperative mapping, with the limitation of aninsufficient spatial resolution. Magneto-encephalo-graphy (MEG) detects magnetic fields generated bycortical activity during patient movement and has goodspatial and temporal resolution, but is a costly and notvery diffuse technique. Furthermore, all these techno-logies require the voluntary performance of a task withdifferent problems of standardization.Transcranial magnetic stimulation (TMS) is anelectrophysiological technique developed for the inve-stigation of human cortical functions. A rapidly chan-ging magnetic field induces a weak electric current byelectromagnetic induction; this can stimulate specificor general parts of the brain with minimal discomfort.Single or paired pulse TMS makes neurons in the neo-cortex under the site of stimulation to depolarize anddischarge an action potential. If used in the motor cor-tex, it produces an involuntary muscle response, na-mely a motor evoked potential (MEP), which can berecorded by electromyogram (EMG) and direct obser-vation. This can be done in real time, namely with thehighest temporal resolution. Furthermore, the deve-lopment of focally stimulating coils allowed the gain ofhigh spatial resolution.Navigated brain stimulation (NBS) is a combination ofTMS with 3-D MRI and computer analysis using a neuro-navigation system, to provide feedback on the exactposition of maximal stimulation. NBS offers differentadvantages for brain mapping over conventional tech-nologies including the fact that it does not passivelyrecord brain activity during voluntary patient move-ments. Instead, NBS actively stimulates the patient’smotor cortex recording EMG changes.Few clinical studies are currently available; they haveshown that preoperative NBS mapping of the motorcortex in brain tumor patients is consistent with preo-perative fMRI mapping and intraoperative direct corti-cal stimulation (DCS). Here we reviewed our experiencein pre-operative brain mapping using NBS and NBScombined with subcortical tractography and direct cor-tical and subcortical stimulation in patients with braintumors including gliomas and metastases.Surgical planning was obtained taking into considera-tion several factors including tumor size and depth,proximity to vessels, proximity to motor and other elo-quent areas, and its presumed histology. Furthermore,to determine the extent of resection and surgical stra-tegies, clinical and demographic characteristics of pa-tients were considered, including age, comorbidities,life expectancy, and personal abilities and preferences.Our preliminary data showed that the NBS had a clearimpact on the planning and surgery by changing theapproach, the planned extent of resection, or even theindications altogether. NBS allowed a precise mapping of the motor cortex andthe visualization of its spatial relationship to the tumor.Finally, comparison with DCS confirmed the spatial reliabi-lity of the pre-surgical brain mapping using NB
Management of aneurysmal subarachnoid hemorrhage: State of the art and future perspectives
No full textBackground: Aneurysmal subarachnoid hemorrhage (SAH) accounts for 5% of strokes and carries a poor prognosis. It affects around 6 cases per 100,000 patient years occurring at a relatively young age. Methods: Common risk factors are the same as for stroke, and only in a minority of the cases, genetic factors can be found. The overall mortality ranges from 32% to 67%, with 10-20% of patients with long-term dependence due to brain damage. An explosive headache is the most common reported symptom, although a wide spectrum of clinical disturbances can be the presenting symptoms. Brain computed tomography (CT) allow the diagnosis of SAH. The subsequent CT angiography (CTA) or digital subtraction angiography (DSA) can detect vascular malformations such as aneurysms. Non-aneurysmal SAH is observed in 10% of the cases. In patients surviving the initial aneurysmal bleeding, re-hemorrhage and acute hydrocephalus can affect the prognosis. Results: Although occlusion of an aneurysm by surgical clipping or endovascular procedure effectively prevents rebleeding, cerebral vasospasm and the resulting cerebral ischemia occurring after SAH are still responsible for the considerable morbidity and mortality related to such a pathology. A significant amount of experimental and clinical research has been conducted to find ways in preventing these complications without sound results. Conclusions: Even though no single pharmacological agent or treatment protocol has been identified, the main therapeutic interventions remain ineffective and limited to the manipulation of systemic blood pressure, alteration of blood volume or viscosity, and control of arterial dioxide tension
Navigated Brain Stimulation (NBS) for Pre-Surgical Planning of Brain Lesion in Critical Areas: Basic Principles and Early Experience
No full textModern neurosurgery attempts to get the difficult goal of combining an "aggressive" resection of brain tumors with the fundamental purpose of preserving brain functions and best possible quality of life.
One of the most important evolutions of neurosurgical therapies is the opportunity to provide a customized surgical intervention by using modern methods to "map" the eloquent areas of the brain. This allows the identification of brain functional areas to be preserved from possible inadvertent intraoperative damage.
Direct cortical stimulation (DCS) is an intraoperative technique that uses electrodes placed directly on the exposed cortical surface of the brain to stimulate activity of functional areas by simultaneously recording the evoked responses peripherally. DCS is very precise and reliable and can be considered the gold standard in brain mapping and intraoperative functional monitoring. Nevertheless, the neurosurgeon discovers the spatial relationship between the disease and eloquent cortical surfaces only after having completed a craniotomy and dural opening.
A pre-surgical mapping method would give the opportunity to plan the treatment of brain diseases optimizing many aspects of the surgical treatment, including patient positioning, type of anesthesia, size of craniotomy, and extent of resection. Moreover, pre-surgical mapping would allow more precise prediction of the efficacy and risks of treatments that can be discussed with the patient and influence the therapeutic strategy.
New techniques have been proposed in an attempt to provide a reliable method for the functional study that can be, however, exploited pre-operatively. The most recent of these methods of mapping cortical activities is navigated brain stimulation (NBS), which is based on the neurophysiological technique of transcranial magnetic stimulation (TMS) of the cerebral cortex combined with the conventional neuronavigation. Basic principles of NBS will be here discussed together with our preliminary experience using this technique in different neurosurgical diseases
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