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Recent data has suggested a role for the nitric oxide metabolite peroxynitrite in peroxidative injury to endothelium associated with atherosclerosis. The present experiments were designed to elucidate whether such a mechanism might be involved in the morphological changes observed during chronic vasospasm after subarachnoid hemorrhage. For this purpose, chronic vasospasm was induced in male Wistar rats by an injection of autologous blood (100 microliters) in the cisterna magna followed by a second injection 24 hours later. Vasospasm was verified by pressure controlled internal carotid angiography after retrograde cannulation of the external carotid artery 7 days after the second injection. Animals were then perfusion fixed and the brains removed for immunohistochemical assessment of nitrotyrosine, the peroxidation product of peroxynitrite with tyrosine contained in tissue proteins. Staining for nitrotyrosine was quantified by microscopy in 40 microns coronal floating sections. The brains of rats with angiographic vasospasm revealed nitrotyrosine predominantly located with a perivascular distribution and in the pia. We conclude that peroxidation of membrane proteins by the nitric oxide metabolite peroxynitrite may contribute to the morphological damage evident in chronic vasospasm.

The object of the neurosurgeons daily endeavour, the human brain, is less well understood in its overall organization than any other organ. This puts the neurosurgeon in a very difficult position. However, a substantial body of knowledge has been accumulated during recent years, and scientists from a variety of different disciplines have worked out theoretical frameworks to accomodate the available data. Here we present some of the evolving concepts on the organization of the substrate of the mind. Review of the literature shows that application of mathematical neural network models to the nervous system is very successful in explaining function. An implicit aspect of neural network models is that information storage is not localized in certain neurons but that the information is stored as the global pattern of activity in the network. Because networks of the brain involve often millions of neurons, exact identification and comparison with the theoretical models is not possible today.

Progress in morphological imaging has facilitated the diagnosis of low-grade glioma (LGG) and plays a decisive role in therapeutic decisions. To date, the method of choice is contrast-enhanced MRI including T1-/T2-weighted and FLAIR sequences. However, tumor delineation and the differentiation between neoplastic and normal brain tissue can be difficult when using morphological MRI and may complicate the identification of anaplastic foci for biopsy and further treatment planning. Furthermore, therapy monitoring and the differentiation of tumor recurrence from unspecific post-therapeutic changes in the tissue are challenging. Additional information about tumor metabolism may be very helpful for the diagnostic assessment of LGG and can be provided by PET. In recent years, the PET amino acid tracer O-(2-[18F]-fluoroethyl)-L-tyrosine (18F-FET) has been clinically validated for brain tumor diagnosis. This tracer has logistical advantages over the widely used PET tracer 11C-methyl-L-methionine due to the longer half-life of the 18F-label (109 vs 20 minutes, respectively). Additionally, it has been demonstrated that both tracers provide comparable diagnostic information. The authors provide an overview of the recent literature regarding the value of various clinical applications of 18F-FET PET in patients with LGG.

Objective In this case report we describe a successful interdisciplinary approach (including flow redirection and endovascular occlusion) applied to a patient with a continuously growing extracranial giant aneurysm of the right internal carotid artery (ICA) due to known Ehlers–Danlos syndrome. Case presentation A 42-year-old man with a continuously growing extracranial giant aneurysm of the right ICA sought treatment after failed surgery of a similar lesion of the left ICA. A multidisciplinary consultation was held at the end of 2008. Treatment strategy The treatment strategy consisted of flow redirection in order to secure sufficient cerebral perfusion prior to surgical trapping of the carotid aneurysm. Flow redirection was achieved by placement of a double-barrel extracranial–intracranial bypass. Subsequent surgical trapping failed due to the extreme size of the aneurysm, making certain identification of surrounding structures impossible. The aneurysm was then successfully occluded by neuroradiological intervention. In a further procedure, a large intra-aneurysmal hematoma was surgically removed to reduce the remaining bulging aneurysm sac. Conclusions This case report describes a successful interdisciplinary approach for the treatment of a rare giant extracranial ICA aneurysm in a patient with Ehlers–Danlos syndrome. Treatment options for this type are few and carry high risks. Flow redirection via extracranial–intracranial bypass followed by endovascular occlusion appears to be a good treatment approach.

Background and purposeTo investigate the effect of locally applied nimodipine prolonged-release microparticles on angiographic vasospasm and secondary brain injury after experimental subarachnoid hemorrhage (SAH).Methods70 male Wistar rats were categorized into three groups: 1) sham operated animals (control), 2) animals with SAH only (control) and the 3) treatment group. SAH was induced using the double hemorrhage model. The treatment group received different concentrations (20%, 30% or 40%) of nimodipine microparticles. Angiographic vasospasm was assessed 5 days later using digital subtraction angiography (DSA). Histological analysis of frozen sections was performed using H&E-staining as well as Iba1 and MAP2 immunohistochemistry.ResultsDSA images were sufficient for assessment in 42 animals. Severe angiographic vasospasm was present in group 2 (SAH only), as compared to the sham operated group (pConclusionsLocal delivery of high-dose nimodipine prolonged-release microparticles at high concentration resulted in significant reduction in angiographic vasospasm after experimental SAH and with no histological signs for matrix toxicity.

Introduction Endovascular treatment of a carotid cavernous fistula (CCF) via a transvenous approach is standard but, in rare cases, the standard approach is not feasible due to vessel occlusion or anomalies. In such cases it remains a challenge to find an alternative route for complete treatment. Clinical presentation A 42-year-old patient presented with a symptomatic CCF (Barrow type C). An endovascular approach to the CCF was not possible due to abnormal venous vessel architecture, so a combined surgical and interventional approach was undertaken. A custom-tailored craniotomy was first performed to access the major sylvian vein. After venotomy and insertion of a microcatheter, the CCF was completely occluded by coiling and embolization conventionally. The symptoms regressed and had almost completely disappeared at follow-up. Conclusions An individually tailored strategy with a combined surgical and endovascular approach enabled full treatment with minimal risk for the patient.

Background Traumatic brain injury (TBI) is probably as old as human beings. The Edwin Smith Papyrus is the first treatise describing the treatment of patients with TBI and allows insights into the medical examination and treatment of head-injured patients in ancient Egypt. Method Clinical, diagnostic, and therapeutic principles in the treatment of TBI in ancient Egypt were analyzed. Results Methodically, cases and the presentation of each case are neatly classified within the papyrus. The papyrus contains the first description of the brain, pulsations, contusions as the result of TBI, the dura, and cerebrospinal fluid, revealing a more or less sophisticated knowledge of cerebral anatomy. Furthermore, ancient physicians examined wounds, fractures, signs of basal skull fractures, and associated neurological or infectious symptoms, and classified the injury pattern according to their prognosis. Therapeutic options at this time seemed to have been limited. Conclusions The Edwin Smith Papyrus reveals asthonishing observation skill when considering the methods and limits of acient times. These physicians were able to recognize many symptoms of TBI and assign them a prognostic value.

Dear Editor,Thank you very much for giving us the opportunity to replyto the comment on our article by Nikolas Lloyd.We really appreciate such comments—especially thosewhich make an effort to improve the standard of science.Thus, the study design and the follow-up were criticized byNikolas Lloyd, and it was suggested to make controlexaminations at 1 and 3 months as well as 2 years. Further, adouble-blinded test was recommended to test effects of themagicpotion(magicpotionvsplacebo).Indeed,thelimitationsofthestudyabouttraumaticbraininjuries(TBIs)intheAsterixcomic books arise from its retrospective study design and theinsufficient follow-up, as emphasized in the “Discussion” ofthe article [1]. Undoubtfully, prospective double-blindedstudies are commonly believed to have greater scientificimpact than retrospective studies with an inconsistent follow-up. Therefore, even medical “Christmas articles” weredesigned as meta-analyses [ 2]. However, characters analysedin the present paper took drugs (the magic potion) in the year50 B.C. and suffered from TBIs in the same year. For us, itwas very difficult to design a study analysing those patientswith follow-up examinations (at 1 and 3 months as well as2 years) in the year 2011 A.D.However,ourarticleaboutTBIsintheAsterixcomicbookswas meant as a Christmas article, even though it was actuallypublished by Acta Neurochirurgica at Easter. Christmasarticles have a tradition in medicine and are frequentlypublished, e.g. by the British Medical Journal [2]. Therefore,our study about TBIs in Asterix comic books was meantneither seriously nor purely as a joke. Besides, our studymight help to focus public attention on TBIs as an importantfield of our daily activities and a leading cause of morbidityand mortality. Further studies on TBI might not only lead to abetter understanding of TBI in Asterix comics but —moreimportantly—might lead to new insights and perhapssubsequently to new therapeutic opportunities for patientssuffering from TBIs.

Object In this study, the authors present a review of a series of 20 intramedullary spinal cord cavernous malformations (SCCMs) with particular focus on MR imaging and prognostic factors. Methods Between 1994 and 2009, 20 patients with SCCM were treated under the care of the senior author. The diagnosis was made in all patients after the onset of clinical symptoms. The age of the 9 men and 11 women ranged between 26 and 71 years (median 38.5 years). The duration of symptoms prior to referral ranged from 1 week to 9 years (median 6.5 months). At the time of referral, 4 patients had no significant neurological deficits, 10 patients suffered significant functional restrictions, and 6 patients presented with severe paraparesis and loss of functional strength. None of the patients had complete paraplegia. Seventeen patients underwent microsurgical removal, while 3 patients opted for conservative therapy. For the present analysis, the medical records and MR images and/or reports were reviewed. Classification of length of history, pretreatment status, MR imaging pattern, and treatment modality was done and correlated with outcome. Results The cavernoma was located at the cervical level in 8 patients and between T-1 and L-1 in 12 patients. The cavernoma appeared as mainly T2 hyperintense on MR images in 7 patients, mainly T2 hypointense in 2 patients, and mixed in the remaining 10 patients. The craniocaudal extension of the core varied between 5 and 45 mm. In 2 patients with cervical cavernomas, a distinct T2 signal of the spinal cord cranial and distal to the cavernoma was seen, and in a patient with a large thoracic cavernoma, T2 extinction cranial and caudal to the cavernoma was seen as a sign of hemosiderosis. Neurological deficits improved postoperatively in 12 of the surgically treated patients, remained stable in 2, and deteriorated in 3. The 3 patients who were conservatively treated remained stable over a follow-up of 3–9 years. Postoperative improvement was seen in 5 of 7 surgical patients with a history of symptoms of 2 months or less, 5 of 6 patients with a history of 2–24 months, and in 2 of 4 patients with a history of more than 2 years. Two of the 3 patients with postoperative deterioration had a history of more than 2 years and the third a short history of 1 month. Conclusions Although a satisfactory outcome can be achieved through surgical treatment of SCCMs, some patients worsen after surgery or during the postoperative course. Long-term stability is possible in oligosymptomatic conservatively treated patients. The prevalence and pathophysiological importance of segmental spinal cord edema and hemosiderosis is incompletely understood at the present time.

50 adult supratentorial low-grade astrocytomas operated upon between 1984 and 1988 were analysed retrospectively with respect to postoperative condition and progression-free survival. Pilocytic lesions were excluded. In 32 instances the tumour was macroscopically completely removed and partially in 4. In 14 cases a stereotactic biopsy was performed only. 10 patients received postoperative radiotherapy with 55 to 65 Gy. 1 patient died perioperatively from pulmonary embolism. 39 patients could resume their previous activities after discharge from the hospital, 10 were significantly disabled by neurological deficit, reduced neuropsychological performance or medically intractable epilepsy. Postoperatively, most patients required continuous anti-epileptic medication. 10 recurrences or tumour progressions of incompletely removed or merely biopsied lesions were observed within the mean follow-up period of 22 months. All recurrences after gross total removal, that were reoperated, had progressed to a malignant glioma. Of the prognostic tumour characteristics analysed, a histologically well-delineated tumour demarcation was most clearly associated with a favourable prognosis. Concerning treatment modalities, gross total resection was associated with a favourable prognosis. Radiotherapy was associated with an unfavourable outcome but this is probably due to selection of otherwise unfavourable cases.

Object. The International Study of Unruptured Intracranial Aneurysms (ISUIA) data raised new controversy regarding the threshold size that requires treatment. In particular, this study has been criticized for disagreeing with previous epidemiological data. Methods. The author first used a Markov model to simulate the natural history of intracranial aneurysms, making three key assumptions based on prospective ISUIA data and other recent reports: that the rate of de novo aneurysm formation is constant after the age of 20 years; that unruptured aneurysms gain volume at a constant rate; and that unruptured aneurysms rupture at a volume-dependent rate. Next, he expressed outcomes for patients with unruptured aneurysms in terms of expected number of quality-adjusted life years (QALY) and compared two hypothetical cohorts, one receiving treatment and the other not being treated. These assumptions enabled the construction of a mathematical model with epidemiologically compatible findings. The benefits of treatment for unruptured aneurysms were highly influenced by aneurysm size and were calculated as -0.28, 0.25, and 1.07 QALY for patients having unruptured aneurysms with diameters of 7, 10, and 13 mm, respectively. Conclusions. Under the author's assumptions, the prospective ISUIA data may be consistent with epidemiological findings. Prophylactic treatment for unruptured aneurysms may produce some benefits in large aneurysms if acceptable treatment risks can be assured, but it is not likely to offer improvement over the natural history for patients with small aneurysms.

The strength of aneurysm walls obtained intraoperatively or at autopsy immediately after death was evaluated by measurements of the force response to one-directional stretch and compared to the walls of intracranial arteries. The maximum stress that aneurysm tissue could tolerate was found slightly lower than in arteries, which is most probably due to the amount of immature forms of collagen. The stress resistance of aneurysms and arterial tissue decayed over a period of several hours. The relaxation curve could be approximated by the sum of 2 exponential terms. The half decay times of these terms were found identical in aneurysms and arteries, they appear to be collagen characteristics. The strength measured in vitro was compared to the stress in vivo, which was calculated on the basis of blood pressure and aneurysm radius. The stress tolerated by aneurysm walls over a period of 24 hours was found to be in the range of the stress that is imposed in vivo by the mean blood pressure. Arteries resisted stresses corresponding to pressures 10 to 20 times higher than physiological values. The thickness of the aneurysm walls correlated with the aneurysm radius in a linear fashion. It is suggested that aneurysm growth can be understood as passive yield to blood pressure, and reactive healing and thickening of the wall with increasing aneurysm diameter.

Repeated Doppler sonograms were performed on the common carotid arteries of patients with severe brain injury. The evolution of the flow-wave shape in 9 patients who developed massive intracranial hypertension and finally died with cerebral circulatory arrest demonstrated that, with increasing peripheral vascular resistance, the diastolic flow diminished while the peak systolic flow was not significantly affected. Thus, the so-called pulsatility index, a measure of the pulsatile characteristic of the sonogram, can be used as a semiquantitative measure of intracranial perfusion. Measurements on healthy control subjects provided pulsatility indexes between 1.5 and 2.0. In cases of posttraumatic brain edema, these values increased gradually. These data suggest that values higher than 3 are associated with severe intracranial hypertension and the decerebrate state. In angiographically demonstrated cerebral circulatory arrest, the pulsatility index was found to range between 6 and 8.

A total of 153 consecutive patients with proven aneurysmal subarachnoid hemorrhages (SAHs) admitted immediately after diagnosis regardless of clinical condition were managed according to the same protocol. The initial evaluation included computed tomography (CT), transcranial Doppler ultrasound (TCD), angiography-CT, and/or angiography. Intravenous nimodipine (2 mg/hour) was started after confirmation of the diagnosis. The timing of operation was determined individually according to age, clinical course, and CT and TCD findings. Twenty-one Grade V patients treated with intensive care and ventriculostomy died or did not improve within 24 hours after SAH. Three patients with life-threatening intracerebral hematomas underwent emergency operation. Operation was early in 55 good risk patients and late in 57 patients because of poor initial grade, late admission, or logistic reasons. Seventeen patients had no operation because of old age, persistent poor clinical condition, medical complication, or lethal rebleeding before operation. In the total series, 90 patients (59%) made a full recovery, the overall morbidity rate was 14% (21 of 153 cases), and the mortality rate was 27% (42 of 153). Postoperative mortality including emergency evacuation of hematomas was 7.8% and mortality after elective operation was 6.2%. The causes of disability and death were the initial effect of the hemorrhage in 25 patients (16.3%), rebleeding in 15 (9.8%), delayed cerebral infarction in 8 (5.2%), surgical complications in 7 (4.5%), hydrocephalus in 4 (2.6%), and medical complications in 4 (2.6%).

A case of a 48 year old women is reported in whom a haemangiopericytic meningioma involving the middle third of the superior sagittal sinus was radically excised. The sinus was replaced by a saphenous vein graft and the Rolandic veins were reinserted. During clamping of the sinus the patient was heparinized and hypothermia, hypotension and barbiturates were used to prevent swelling of the brain. The postoperative course was uncomplicated and patency of the graft was demonstrated 2 weeks after the operation by Doppler sonography performed through a midline burr hole. The technical details of the operation and the pertinent physiology of cerebral venous flow are discussed.

SYNOPSIS The somatotopic representation of the cranial dura mater and the major cerebral arteries in the semilunar ganglion of the cat has been studied experimentally. Neuroanatomical tracer substance was applied to various dural sites as well as to the internal carotid and middle cerebral artery and labeled cells were subsequently identified in the trigeminal ganglion. Cells in the first trigeminal division were found to innervate the medial aspect of the anterior cranial fossa, the tentorium cerebelli and the intracranial carotid and the middle cerebral artery. Neurons associated with the orbital roof were located predominantly in the dorsal and intermediate layers of the second division while the dura of the middle fossa was represented mainly in the dorsal strata of the third division. Labeled cells were smaller than the average ganglion cell.

Tissue strength and stiffness of cerebral aneurysm walls obtained intraoperatively or at autopsy were evaluated by uniaxial strain/stress measurements. For comparison, corresponding measurements were also made on autopsy specimens of intracranial arteries. The maximum stress that the aneurysm tissue could tolerate, the yield stress, was found to be slightly lower than in arteries, which is likely due to the content of immature forms of collagen. The material stiffness, as determined by division of the yield stress by the corresponding strain, was also smaller in aneurysms than in arteries. The stress resistance of aneurysms and arterial tissue decreased over a period of several hours. The relaxation curves were found to be identical in aneurysms and arteries. The stress tolerated by aneurysm walls was found to be in the range of the stress that is imposed in vivo by the blood pressure. Arteries resisted stresses corresponding to pressures 5–10 times higher than physiological values. It is suggested that the balance of tissue strength and the stress imposed by the blood pressure is causally related to aneurysm growth.

Basic flow patterns were investigated in a set of glass aneurysm models by means of flow visualization methods. Dye injection and streaming double refraction were used to visualize flow. The circulation inside lateral aneurysms arising at a 90 degree angle from a straight parent conduit could not be visualized by the dye-injection technique but could be demonstrated by streaming double refraction. The inflow was seen to arise from the downstream lip of the orifice and to project to the dome of the aneurysm. Backflow to the parent conduit took place along the walls of the aneurysm. In aneurysms located at bifurcations, flow characteristics depended on the geometry of the bifurcation and the flow ratio between the branches. Relatively little intra-aneurysmal flow was demonstrated in side branch-related aneurysms arising distal to an asymmetric 90 degrees bifurcation of the type encountered at the junction of the internal carotid and posterior communicating arteries. Stagnation of flow at the neck and little intra-aneurysmal circulation were found with terminal aneurysms of the basilar bifurcation type if the outflow through the branches was symmetric. With asymmetric outflow, however, or if the axis of the aneurysm did not coincide with that of the afferent vessel, an active rotation developed in these aneurysms. The size of the aneurysm had no influence on the basic pattern of intra-aneurysmal circulation. The use of pulsatile perfusion did not significantly alter the basic flow patterns observed with steady flow. Locally disturbed laminar flow was observed in certain models at physiological Reynold's numbers, but there were no signs of fully developed turbulence.

The representation of the dura mater in the trigeminal ganglion was examined in the cat using the horseradish peroxidase (HRP) method. Following craniotomy a 50% solution of HRP was applied to various areas of the cranial dura and after a survival time of 48 h the trigeminal ganglion was processed. Cells in the first division gave rise to fibers innervating the medial aspect of the anterior fossa as well as the tentorium cerebelli. Labeled cells associated with the orbital roof were located predominantly in the dorsal and intermediate layers of the second division while the middle fossa was found to be represented mainly in the more dorsal strata of the third division. Labeled cells were smaller than the average ganglion cell.

Background Spontaneous infectious spondylodiscitis is a rare, but serious disease with the risk of progressive neurological impairment. The surgical approach to spontaneous infectious spondylodiscitis is in most cases an anterior debridement and fusion, often in staged surgeries. Here we report a case of single-stage posterior debridement and posterior instrumented fusion in combination with an injectable calcium sulfate/hydroxyapatite composite eluting gentamicin. Case presentation A 59-year-old Caucasian man presented with a 6-week history of lumbar pain without sensory or motor disorders of his lower extremities. A magnetic resonance imaging scan of his lumbar spine in T2-weighted sequences showed a high signal of the intervertebral disc L4/L5 and in T1-weighted sequences an epidural abscess at the posterior wall of L4. Additional computed tomography imaging revealed osteolytic destruction of the base plate of L4 and the upper plate of L5. Antibiotic therapy was started with intravenous ciprofloxacin and clindamycin. We performed a posterior debridement via a minimally invasive approach, a posterior percutaneous stabilization using transpedicular screw-rod instrumentation and filled the intervertebral space with an injectable calcium sulfate/hydroxyapatite composite which elutes a high concentration of gentamicin. The patient’s lower back pain improved quickly after surgery and no recurrence of infection has been noticed during the 1-year follow-up. Computed tomography at 11 months shows complete bony fusion of L4 and L5. Conclusions An injectable calcium sulfate/hydroxyapatite composite releasing a high level of gentamicin can support the surgical treatment of spondylodiscitis in combination with posterior debridement and transpedicular screw-rod instrumentation.