Comparison between autologous bone grafts and acrylic (PMMA) implants - A retrospective analysis of 286 cranioplasty procedures.

Decompressive craniectomy (DC) is an accepted surgical technique for reducing life-threatening levels of intracranial pressure. Remodelling the cranial vault following DC can constitute a reconstructive challenge and is known to carry significant morbidity. The aim of our study was to evaluate acrylic versus autologous cranioplasty with regard to specific complication rates. A retrospective analysis was conducted of 286 consecutive adult patients who underwent cranioplasty following supratentorial decompressive craniectomy at our institution between January 2003 and June 2013. The patients were followed based on medical records, operative reports, imaging and outpatient contacts in the postoperative course. A total of 221/286 patients in our series received an autologous bone flap. 65/286 cranioplasty procedures were carried out using acrylic (PMMA) implants to cover uni- or bilateral defects. Within the follow-up period a total of 100 operative revisions were performed. 33.3% patients in the autologous bone group and 40.6% of patients in the acrylic group developed complications requiring surgical attention. The main reason for revision was infection with a total of 37 revisions necessary to treat disturbed wound healing. Postoperative sub- and epidural hematomas requiring revision were more frequent in the acrylic group. Resorption of the autologous bone flap requiring operative revision was seen in 8/222 (3.6%) cases. Other complications included loosening of the implant or dislocation. From our data it can be concluded that cranioplasty procedures using autologous bone-flaps and acrylic implants carry signifikant morbidity, but that both are justifiable techniques for cranioplasty in adult patients.

Relative survival of patients with non-malignant central nervous system tumours: a descriptive study by the Austrian Brain Tumour Registry.

BACKGROUND: Unlike malignant primary central nervous system (CNS) tumours outcome data on non-malignant CNS tumours are scarce. For patients diagnosed from 1996 to 2002 5-year relative survival of only 85.0% has been reported. We investigated this rate in a contemporary patient cohort to update information on survival. METHODS: We followed a cohort of 3983 cases within the Austrian Brain Tumour Registry. All patients were newly diagnosed from 2005 to 2010 with a histologically confirmed non-malignant CNS tumour. Vital status, cause of death, and population life tables were obtained by 31 December 2011 to calculate relative survival. RESULTS: Overall 5-year relative survival was 96.1% (95% CI 95.1-97.1%), being significantly lower in tumours of borderline (90.2%, 87.2-92.7%) than benign behaviour (97.4%, 96.3-98.3%). Benign tumour survival ranged from 86.8 for neurofibroma to 99.7% for Schwannoma; for borderline tumours survival rates varied from 83.2 for haemangiopericytoma to 98.4% for myxopapillary ependymoma. Cause of death was directly attributed to the CNS tumour in 39.6%, followed by other cancer (20.4%) and cardiovascular disease (15.8%). CONCLUSION: The overall excess mortality in patients with non-malignant CNS tumours is 5.5%, indicating a significant improvement in survival over the last decade. Still, the remaining adverse impact on survival underpins the importance of systematic registration of these tumours.

Patients with recurrent glioblastoma multiforme. Initial experience with p-[(131)I]iodo-L-phenylalanine and external beam radiation therapy.

AIM: The objective of this study was to assess the feasibility, dosimetry, tolerability and efficacy of systemically administrated p-[(131)I]iodo-L-phenylalanine ((131)IPA) combined with hypo-fractionated external beam radiation therapy (EBRT) in patients with recurrent glioblastoma multiforme (GBM). PATIENTS, METHODS: Five patients (2 women, 3 men, aged 27-69) with recurrent GBM and exhaustion of regular therapy options were included. All had a positive O-(2-[(18)F]Fluoroethyl)-L-tyrosine positron emission tomography (FET-PET) and pretherapeutic dosimetry was performed. Tumour targeting was verified by (131)IPA-SPECT up to six days after radiotracer administration. After (131)IPA therapy, patients were treated with hypo-fractionated EBRT in six fractions of 5 Gy (n = 4) or in eleven fractions of 2 Gy in one case. RESULTS: Based on the individual dosimetry, the patients received a single intravenous administration of 2 to 7 GBq of (131)IPA, resulting in radiation absorbed doses to the blood of 0.80-1.47 Gy. The treatment was well tolerated; only minor complaints of nausea and vomiting that responded to ondansetron and pantoprazol were noticed in the first two patients. After preventive medication, the last three patients had no complaints during therapy. In none of the patients a decrease of leukocyte or thrombocyte counts below the baseline level or the lower normal limit was observed. Tumour doses from (131)IPA were low (≤ 1 Gy) and all patients died three to eight (median 5.5) months after therapy. CONCLUSION: In this initial experience, treatment of GBM with (131)IPA in combination with EBRT was demonstrated to be safe and well tolerated, but less effective than suggested by the animal studies.

Fatal recurrent subarachnoid hemorrhage after complete endovascular aneurysm occlusion.

Endovascular treatment of aneurysms has become an alternative to the neurosurgical approach. Here, we describe a patient presenting with a subarachnoid hemorrhage (SAH) due to a basilar tip aneurysm, which was completely occluded with coils. Fourteen days later the patient died due to massive recurrent SAH. Histologic evaluation showed aneurysm rerupture with coil dislocation in the subarachnoid space. This is a rare histologically documented case of fatal recurrent hemorrhage early after coil embolization of cerebral aneurysms.

Epigenetic repression of RASSF1A but not CASP8 in supratentorial PNET (sPNET) and atypical teratoid/rhabdoid tumors (AT/RT) of childhood.

Supratentorial primitive neuroectodermal tumors (sPNET) and atypical teratoid/rhabdoid tumors (AT/RT) of the CNS represent a biological and clinical enigma, despite advances in both molecular techniques and clinical management for these two rare embryonal brain tumors of childhood. Epigenetic changes hold great potential as possible disease mechanisms and may be manipulated therapeutically. We thus studied aberrant methylation of the genes RASSF1A and CASP8 and its consequence on expression in cell lines and primary tumors using a combination of semiquantitative methylation specific PCR (MSP), bisulfite sequencing and RT-PCR. In all, 17 samples of autopsy-derived normal appearing brain served as controls. Opposed to control tissues 19/24 sPNET and 4/6 AT/RT demonstrated aberrant methylation for the RASSF1A promoter region. Treatment of cell lines using 5-Aza-2'-deoxycytidine (5AZA) alone or in combination with trichostatin A (TSA) succeeded in re-establishing expression of RASSF1A in cell lines derived from a renal rhabdoid, an AT/RT and a medulloblastoma. A 5' CpG-rich region of CASP8 was methylated in normal tissues and in tumors. However, CASP8 showed inconsistent expression patterns in normal and tumor tissues. Our results indicate that aberrant methylation of the RASSF1A promoter region may be of importance in the origin and progression of sPNET and AT/RT while the analysed 5'-CpG rich region of the CASP8 gene does not seem to play an important role in these tumors. Further studies of epigenetic changes in these rare tumors are warranted as their biology remains obscure and treatment efforts have been rather unsuccessfull.

Extraneural metastases of primary brain tumors.

Extraneural metastasis (ENM) of primary brain tumors is arare occurence. Based on acritical analysis of the literature the present review focuses on illustrating special common features of these tumors with regard to immunological, cytokinetical and tumorbiological issues. In this respect much can be learned from the specific conditions following organ transplantation which is extensively discussed.

Medulloblastoma displays distinct regional matrix metalloprotease expression.

Matrix metalloproteases (MMPs) play an important role in tissue remodeling and neoangiogenesis during tumor progression. Little is known about the presence and regional distribution of MMPs in medulloblastomas. Based on immunohistochemical, immunocytochemical and zymographical analysis is the present study illustrates the differential pattern of MMP expression for the medulloblastoma compared to that of glioma and ependymoma. In 10 examined medulloblastoma tumors gelatinase-A was strongly expressed by clusters of tumor cells. Gelatinase-B was, similar to glioma and ependymoma, predominantly found around endothelial cells. The DAB signal for macrophage metalloelastase was seen around macrophages and matrilysin was expressed by single tumor cells. Stromelysin-1 protein was detected in medulloblastoma but not in glioma or ependymoma. From the presented data it follows that each tumor entity might display its own characteristic MMP expression pattern.

New ultrasound techniques and their application in neurosurgical intra-operative sonography.

We describe a variety of new ultrasound techniques by their physical background, potentials and applications regarding usefulness during intra-operative neurosurgical procedures. Transducers like high-frequency and small rotating probes fitting into neuroendoscopes, imaging techniques as extended field-of-view technique, harmonic imaging, echo-enhancers, 3-D imaging and the real-time integration of neurosonography with pre-operative CT- or MR-data are mentioned. The technical or physical principles are explained, followed by a discussion of these techniques from available literature dealing with their intra-operative neurosurgical applications and the experience of the authors with the techniques. With higher frequencies micromillimeter imaging is possible and small probe allows endoneurosonography. Echo-enhancers and harmonic imaging improve the signal-to-noise ratio and 3-D imaging and extended field-of-view techniques allows a better understanding of the pathoanatomy. With the real-time integration of intra-operative ultrasound images and pre-operative CT or MR images additional information, like hemodynamic pattern, are available for the neurosurgeon. Although until now only a limited number of reports about new sonographic techniques during intra-operative application in neurosurgery exist, the methods seem to be promising in creating images easier to understand, incorporating more information about pathoanatomy and supplying the neurosurgeon with information additional to that provided by CT and MRI.

MRI in isolated sixth nerve palsies.

In previous studies the origin of the majority of isolated sixth nerve palsies was not clear or was ascribed to vascular disease. Our purpose was determine how frequently a causative lesion was demonstrated on MRI in patients with an acute unilateral sixth nerve palsy. We performed a prospective study of 43 patients using a standardised protocol. In 27 patients (63%) a lesion was identified on the initial MRI relevant to the sixth nerve palsy; 21 (49%) were found to have a tumour or tumour-like lesion; the frequency of presumed vasculopathy in this group was 15%. There were 16 patients (37%) with an initially normal MRI, of whom 10 (62%) had a history of vasculopathy, a significantly different proportion from the group of patients with a visible causative lesion. MRI after 3-6 months was normal in all patients with a normal initial MRI. We suggest that MRI should routinely be performed in patients presenting with an acute sixth nerve palsy, even those with evidence of a vasculopathy. If the symptoms regress spontaneously and there is a history of vasculopathy, follow-up MRI is not necessary.

Heterogeneous regional expression patterns of matrix metalloproteinases in human malignant gliomas.

The aim of the study was to assess the differential intra- and intertumoral heterogeneity and patterns of matrix metalloproteinase expression in human glioblastomas in vivo. 12 glioblastoma samples were analyzed for MMP expression by semi-quantitative RT-PCR. A total of 56 samples (8 adjoining regions of 6 glioblastoma tumors) were immunohistochemically examined for the expression and regional distribution of gelatinase-A (MMP-2), gelatinase-B (MMP-9), matrilysin (MMP-7) and stromelysin-1 (MMP-3). Gelatinase-A mRNA was detected in all samples, gelatinase-B was found in numerous samples. Correspondingly, strong expression levels of both gelatinase protein was seen in immunohistochemistry. Gelatinase-A was expressed by both tumor cells and endothelium while gelatinase-B was found to be restricted to endothelial cells. Stromelysin-1 protein was not detected in any of the samples. Matrilysin was found around tumor cells of three samples from one patient only. The strong immunoreactivity seen for gelatinase-A around tumor cells and blood vessels suggests a role in both tissue degradation and tumor neoangiogenesis which is in accordance with previously published in vitro data. The marked localization of gelatinase-B to the endothelium and its presence in non-infiltrative benign lesions, however, makes a direct proteolytic role of gelatinase-B on ECM components during glioma invasion appear unlikely. Its close association with vascular structures, however, might indicate a link to neoangiogenesis. The significance of matrilysin which was only seen in tumor cells in three samples remains unclear. Stromelysin-1, though strongly expressed in cell lines, does not appear to play a role in glioblastoma tumors in vivo.

Different vascular patterns of medulloblastoma and supratentorial primitive neuroectodermal tumors.

Astrocytoma vasculature patterns differ according to histological grade of malignancy with glioblastoma multiforme (WHO grade IV) showing most extensive endothelial proliferation. Here, we determined whether the vascular patterns of medulloblastoma and supratentorial primitive neuroectodermal tumors (PNETs), which can be hardly distinguished histopathologically, differ. We evaluated the spatial organization of vessels in medulloblastomas and PNETs using antibodies to von Willebrand factor (vWF) and CD34. Medulloblastoma capillaries showed slight endothelial cell hyperplasia. Microvessels sprouted from the capillaries and formed glomeruloid clusters. There were areas with chains of unopposed endothelial cells (3-10 cells). Supratentorial PNETs had highly branched capillaries with extensive endothelial cell hyperplasia. Glomeruloid arrays of microvessels extended from the capillaries. Small fragments of endothelial tubes were scattered throughout the tumor. Therefore, medulloblastomas and supratentorial PNETs showed different spatial organization of tumor vessels which can be used for differentiation of each tumor entity. These vascular patterns may reflect different tumor derived angiogenic stimuli.

Microglial/macrophage expression of interleukin 10 in human glioblastomas.

Interleukin 10 (IL-10) expression has been found to be correlated with the extent of malignancy in gliomas. In vitro, IL-10 increases proliferation and migratory capacity in human glioma cell lines. In this study, we localized the site of IL-10 synthesis in gliomas to cells of microglial origin. Biopsy specimens from 11 patients with malignant glioma were processed on native tissues and at early cell culture passages (0-4). IL-10 mRNA was analyzed by RT-PCR and in situ hybridization. Protein was quantitatively assessed by ELISA in cell culture supernatants, and cells expressing IL-10 were determined by a combination of immunohistochemistry for CD68 (specific for microglia/macrophage lineage) and IL-10 in situ hybridization. IL-10 mRNA decreased from passage 0 to 4 in all samples and was undetectable beyond passage 5. Such downregulation of mRNA leads to a steep decrease of IL-10 protein in culture supernatants (below detection level, 0.05 ng/ml, beyond passage 1). The combination of in situ hybridization for IL-10 and CD68 immunostaining revealed that only cells of the microglia/macrophage lineage produced IL-10 mRNA. Our results identify microglia/macrophage cells as the major source of IL-10 expression in gliomas which decreases markedly during early passages of primary cultures of human gliomas due to a progressive reduction of microglia/macrophages present.

Effect of synthetic matrix-metalloproteinase inhibitors on invasive capacity and proliferation of human malignant gliomas in vitro.

Glioma invasion into the surrounding brain tissue is still a major obstacle for any therapeutical approach. As in other solid tumors, matrix-metalloproteases (MMPs) have been suggested as being involved. The aim of this study was to evaluate whether the use of MMP inhibitors to target the protease-mediated invasion process could be a feasible approach. Two human cell lines (U251 and GaMG) and surgical specimens of 6 patients with malignant gliomas were grown as monolayers and spheroid cultures respectively. MMP- and u-PA-mRNA expression was investigated by semi-quantitative RT-PCR. Invasion was studied in Matrigel-coated Boyden chamber transwell assays for monolayers and in confrontation cultures of tumor spheroids with fetal rat brain aggregates in the presence of the synthetic MMP inhibitors batimastat (BB-94) and marimastat (BB-2516). Cytotoxicity/cytostatic effects of high concentrations of both compounds were assessed by growth curves, MTT assays and flow cytometry in human glioma cell lines. Batimastat and marimastat revealed a cytostatic effect at high concentrations (above 1 microM) without cytotoxicity. Both MMP inhibitors effectively reduced glioma invasion in Boyden-chamber assays at low concentrations of 0.3 microM. In confrontation cultures, concentrations of 10 microM and above were necessary to reduce invasion. This effect was observable with inter-individual heterogeneity in the patient's tumor material. MMP inhibitors effectively reduce glioma invasion, although high concentrations were required in 3-dimensional culture systems. At these concentrations, both compounds revealed a cytostatic, but no cytotoxic effect. Thus, high local concentrations of MMP inhibitors could offer a new therapeutic strategy for the treatment of gliomas.

Interrelations of laser doppler flowmetry and brain tissue oxygen pressure during ischemia and reperfusion induced by an experimental mass lesion.

The objective of this study was to assess interrelations between bilateral changes of cortical laser doppler flowmetry and intraparenchymal, subcortical partial tissue oxygen tension in the course of an experimental trauma. Ten animals served as a sham group, 8 Sprague-Dawley rats received an unilateral, focal parietal mass lesion. The bilateral course of cortical blood flow measured by laser doppler flowmetry (LDF) was correlated with subcortical, intraparenchymal partial tissue oxygen tension [p(ti)O2]. In the sham-operated group, laser doppler mean flow values drifted between 9.0% and 9.5% and showed no significant changes over time neither between the hemispheres nor within each hemisphere. Absolute mean p(ti)O2 in sham-operated animals was 32.4 mm Hg in the left and 30.5 mm Hg in the right hemisphere. In the trauma group, mean laser doppler flow values during maximum brain compression decreased ipsilateral to 20.3% and contralateral to 34.4% of the baseline values. P(ti)O2 decreased ipsilateral from 25.9 to 6.6 mm Hg (25.4%) and contralateral from 22.6 to 9.8 mm Hg (43.6%). After balloon deflation, cortical LDF was restored much faster compared to p(ti)O2, but did not reach baseline values [ipsilateral 61.6% (p < 0.05); contralateral 75.8% of baseline values]. The p(ti)O2 values reached 25.2 mm Hg (97%) ipsilateral and 23.7 mm Hg (105%) contralateral. A temporary phase of reactive hyperemia occurred sporadically shortly after decompression. Both parameters showed a significant but rather weak correlation (r = 0.56; p < 0.001). Based upon these findings, we conclude that intraparenchymal, subcortical p(ti)O2 measurements supplemented on-line cortical CBF monitoring and score out discontinuous alternative measurement techniques in detecting hemodynamically relevant events. The small spatial resolution of LDF and p(ti)O2 probes, however, which in the small animal model may be of negligible influence, does raise the question whether the values obtained represent the microcirculatory situation of the human brain.

Vascularization of human glioma spheroids implanted into rat cortex is conferred by two distinct mechanisms.

Aim of this study was to develop and characterize an applicable in vivo model to investigate angiogenesis of human gliomas. An established glioblastoma spheroid model was used to investigate the neovascularization of a standardized avascular solid tumor mass. Spheroids of two human glioma cell lines were labeled with an in vivo fluorescent dye. Single spheroids were implanted into the cortex of athymic rats. After 1, 3, 7, 14, and 21 days, brain sections containing the spheroid were immunostained for endothelial cells or vascular endothelial growth factor (VEGF). The dye-stained glioma spheroid and the endothelial cells were visualized by confocal microscopy. Two distinct mechanisms of tumor vascularization could be observed. (1) "Classical" angiogenesis with new vessels sprouting from existing host vessels into the spheroid was seen. (2) Individual endothelial cells were found to migrate towards and into the center of the spheroid where they coalesced to form new vessels. This process occurred as early as 24 hr after spheroid implantation. Spheroid vascularization was accompanied by an increase of VEGF expression, which peaked 7 days after implantation and returned to normal patterns by 14-21 days. Besides the "classical" angiogenesis by angiogenic blood vessels, the recruitment of individual endothelial cells seems to be an additional mechanism in early glioma vascularization. Our model proves to be a reliable, reproducible system to study in vivo angiogenesis of human gliomas.

Bilateral monitoring of CBF and tissue oxygen pressure in the penumbra of a focal mass lesion in rats.

The continuous monitoring of cerebral microcirculation is aimed at preventing secondary ischemic brain damage subsequent to severe head injury. Interrelations between bilateral changes of cortical Laser Doppler Flowmetry (LDF) and intraparenchymal, subcortical p(ti)O2 values were continuously monitored in the forebrain of rodents. A trauma group of 8 animals received an unilateral, focal parietal mass lesion by an expanding epidural balloon. 10 animals served as a sham group. In the sham-operated group the drift of median LDF values was 10.8% in the left and 9.6% in the right hemisphere. The absolute median p(ti)O2 showed values of 31.2 mm Hg (27.9-34.9) in the left and 30.1 mm Hg (27.5-31.7) in the right hemisphere. During maximum brain compression median LDF values decreased ipsilateral to 18.6% (13.3-24.4%) and contralateral to 23.4% (17.1-56.6%) of the baseline values. P(ti)O2 decreased ipsilateral to absolute values of 4.6 mm Hg (3.2-6.7 mm Hg) and contralateral to values of 7.1 mm Hg (6.1-8.5 mm Hg). After balloon deflation cortical LDF was restored much faster but did not reach baseline values [ipsilateral 55.2% (42.6-67.8%); contralateral 67% (53.4-82%) of baseline values]. The p(ti)O2 values reached ipsilateral 77.4% (72.0-93.3%) and contralateral 88.8% (86.0-97.4%) of baseline values. Both parameters showed a significant correlation (r = 0.57; p < 0.02). P(ti)O2 measurements supplement on-line cortical CBF monitoring and by far outscore discontinuous alternative measurement techniques in detecting hemodynamically relevant events. The small spatial resolution of the p(ti)O2 probes, however, which in the small animal model may be of negligible influence, does raise the question whether the values gained offer a general overview of the microcirculatory situation.

Guanidinobenzoatase and UPA in high-grade human astrocytomas and after xenografting cell suspensions into the rat cerebral cortex: proteases for metastasis and disease progression.

BACKGROUND: Invasion and metastasis is aided by the secretion of guanidinobenzoatase, that cleaves the link peptide to fibronectin, and urokinase plasminogen activator (uPA), which initiates a molecular cascade to activate plasmin and collagenases. This process permits malignant cell migration through the extracellular matrix. MATERIALS: Original human astrocytomas were examined for guanidinobenzoatase and uPA. Suspensions of high-grade human astrocytomas were xenografted into pockets in host cerebral cortex for 1-7 days. RESULTS: A class of guanidinobenzoatase positive cells was observed in the original human astrocytomas and in tumor masses formed in the implantation pocket and around blood vessels. Secondary foci containing guanidinobenzoatase positive cells formed around blood vessels and individual positive astrocytoma cells migrated on the glia limitans along parallel and intersecting nerve fiber fascicles and the corpus callosum. uPA and GFAP were colocalized with guanidinobenzoatase. CONCLUSION: The high-grade astrocytomas reestablish themselves and maintain their characteristics as a tissue although grafted as individual cells.

Fast blue, a fluorescent tracer in glioma cell culture, affects cell proliferation and motility.

The azo-dye, Fast Blue (FB), initially employed for retrograde neuronal tracing is increasingly used in cell invasion and migration studies to detect living cells in monolayer and glioma tumor cell spheroid models. As yet, it is assumed that a cell stained with a tracker dye retains the characteristics of the original cell. The following experiments compared the adhesion, migration and proliferation properties of the cell lines U373 and GaMG with and without FB staining. FB staining reduced cell adhesion (P < 0.01) and proliferative activity (P < 0.01) and also had a significant inhibitory effect on cell migration (P < 0.001). From the results presented it follows that FB staining markedly influences basic cell characteristics.

Transfection and dye premarking of human and rat glioma cell lines affects adhesion, migration and proliferation.

It is assumed that a cell that is transfected for any gene addition or replacement or was premarked with a cell tracker dye retains the characteristics of the original cell. The following experiments compare the original C6 rat glioma cell line with C6 cells transfected with the retroviral plasmid LacZ, and the human glioma cell lines GaMG, U373, U251, and D54 with cells stained with tracker dyes (Dil and DiO). We tested adhesion, migration and proliferation. C6 cell transfection did not affect adhesion but decreased (p < 0.05) migration. Dil staining resulted in a significant decrease (p < 0.01) in adhesion in all cell lines but U251. After DiO staining human cell lines U373 and D54 displayed a decrease in adhesion (p < 0.01) whereas U251 and GaMG cells had enhanced adhesion (p < 0.01). Dye marking of C6, GaMG and U373 cells did not alter migratory capacity. In contrast, Dil and DiO reduced migration of U251 and D54 cells (p < 0.05). There was a decrease (p < 0.01) in proliferation of the human cell lines after Dil staining. Transfection or membrane dyes can alter basic cell characteristics. The assumption that a transfected or dye marked cell is the same as the original cell but with an additional gene or the presence of a dye in the membrane is untenable.