Statistical evaluation of measured biomechanical properties of human brain aneurysm samples.

Background and purpose:

Human brain aneurysms may often prove fatal if not re­cognized in time and treated accordingly. The understanding of development and rupture of aneurysms can significantly be improved by the application of numerical modelling, which in turn, requires the knowledge of mechanical properties of vessel wall. This study aims to identify assumed differences with respect to age, sex, spatial orientation, and rupture by utilizing detailed statistical analysis of uniaxial tensile measurements of human brain aneurysm samples, performed by the authors in a previous project.

At surgery of 42 patients, aneu­rysm fundi were cut distally to the clip. In each case, depending on size, varying number of stripes (altogether 88) were prepared and uniaxial stress-strain measurements were performed. Quantities related to the capacity, energy absorption or stiffness were determined and statistically analysed.

The number of specimens in the aneurysm sample was sufficient to establish statistical differences with respect to sex and rupture (p<0.05). No significant differences were detected in orientation, though higher values of stresses and deformations were ob­tained in the circumferential direction com­pared to the meridional direction. 

Significant differences bet­ween sexes with respect to ultimate deformations were demonstrated according to expectation, and the hypothesis on equality of energy capacity could be supported. Similarity of curves with respect to specimen orientation was also observed and ruptured aneurysm sacs tended to be smaller in size. It seems that differences and trends described in this paper are realistic and need to be applied in numerical modelling.

Anterior communicating artery aneurysm rupture and functional outcome in short-term: clipping versus coiling.

Our research aims to assess the change in the grade of responsiveness using the Hunt and Hess score as well as the modified ranking scale in patients suffering from anterior communicating artery rupture. We retrospectively analyzed data from 11-patients who suffered from an anterior communicating artery aneurysm rupture that caused a subarachnoid hemorrhage. Severity was assessed using the Hunt and Hess scale grade and modified ranking scale. Anterior communicating artery rupture caused a subarachnoid hemorrhage in 40.81% of all aneurysm ruptures that took place at the Circle of Willis. Unfortunately, 4-patients deceased (3.4%) at a median age of 52-years (range 34-75-years), three of which deceased after coiling and one after clipping. In 71-patients (61.2%) endovascular coiling was performed - 33-males and 38-females - and in the remaining 45-cases, (38.8%) clipping was indicated - 24-males and 21-females. Overall, the pre-interventional median Hunt and Hess scale was 2, which remained after the intervention. When relating the outcome score to the intervention performed, we found that the Hunt and Hess scale score was 3 before coiling and 2 before clipping, whereas afterward, there was a slight increase to 2 and 2, respectively. The modified ranking scale was 2 after clipping, respectively, coiling (P = 0.218). No significant differences were observed between the different groups. Our results show that clipping is as effective as coiling in terms of the Hunt and Hess scale and the rate of mortality in the short-term.

Long-Term Outcome of Endonasal Transsphenoidal Approach for the Treatment of Pontine Cavernous Malformation: Case Report with 11 Years of Follow-Up.

Ventromedial localized cavernous malformations in the pons pose a difficult problem because of their surgical access and the high risk of deleterious consequences due to damage of the surrounding tissues. We report an endonasal transsphenoidal approach for the treatment of ventromedial pontine cavernomas that also follows principles of optimal access known as the "two-point method" for the resection of cavernous malformations. A 31-year-old woman presented with sudden left hemiparesis, nausea, and headache. Radiologic findings demonstrated a ventral pontine cavernous malformation in the midline slightly extending to the right, together with signs of acute hemorrhage. Surgical intervention was performed, and the cavernoma was completely resected via a transnasal transsphenoidal approach. Cerebrospinal fluid (CSF) rhinorrhea that ensued postoperatively needed an additional reconstructive surgery using the same approach. No further CSF leakage was evident, and an 11-year follow-up examination revealed neither signs of neurologic deficit nor recurrence of the resected pontine cavernoma. The long-term outcome proves the effectiveness and safety of this novel surgical route in the treatment of ventromedial cavernous malformations in the pons.

Long-term effectiveness of an ad hoc tailored titanium implant as a spacer for microvascular decompression in the treatment of trigeminal neuralgia caused by megadolichoectatic basilar artery anomaly: 9-year follow-up.

An enlarged, elongated, ectatic, and sclerotic aberration of the vertebrobasilar system is known as a megadolichoectatic basilar artery (BA) anomaly. The anomaly is often involved in the pathological process of trigeminal neuralgia by compressing and distorting the trigeminal nerve. First-line medical treatment includes drug therapy, but a second-line surgical procedure could be effective in medication-resistant cases. The authors report the case of a 65-year-old man with a 12-year history of progressing trigeminal neuralgia who underwent microvascular decompression after the first-line drug treatment had failed. This case is unique because an in situ tailored titanium microplate was used as a spacer to alleviate compression by the BA on the trigeminal nerve. The titanium implant provided durable and sufficient retraction for the sclerotic arterial complex when the trigeminal nerve was placed in the tunnel of the implant. The 9-year follow-up examination proves the safety and long-term efficacy of titanium implants in the treatment of trigeminal neuralgia caused by a megadolichoectatic BA anomaly. The method applied in this case was not intended to be and certainly is not an alternative to routine microvascular decompression-this surgical solution may be reserved for some extreme cases.

Morphological observations in brain arteriovenous malformations after gamma knife radiosurgery.

Morphological studies after Gamma Knife radiosurgery (GKRS) revealed endothelial destruction followed by spindle-shaped cell proliferation in the subendothelial region and in the connective tissue stroma of arteriovenous malformation (AVM) vessels. Histological, immunohistochemical and ultrastructural characteristics of this spindle-shaped cell population in the irradiated AVMs were reminiscent of those described as myofibroblasts in wound healing processes and pathological fibromatoses. These modified fibroblasts have contractile capacity, therefore this might contribute to the vessel occlusion, shrinking process and final volume reduction of AVMs after GKRS. Similar histopathological changes were observed in a cavernous malformation following high-dose irradiation.

Rare angioproliferative tumors mimicking aggressive spinal hemangioma with epidural expansion.

BACKGROUND AND PURPOSE: We present two cases of angio-proliferative tumors that were misdiagnosed and treated as typical hemangiomas with epidural expansion. MATERIALS AND METHODS: Two middle-aged women presented with symptoms and radiological signs characteristic for aggressive hemangioma with epidural expansion. In the first case preoperative embolization and decompressive surgery with open transpedicular vertebroplasty was performed. Within less than a year, epidural recurrence of the tumor prompted for radical excision and corpectomy. The diagnosis after the histological studies and the further clinical evolution was metastasizing leiomyomatosis. No further recurrence occured during the next 6 years. In the second case percutaneous vertebroplasty was performed and complicated by epidural polymethyl-methacrylcate (PMMA) leakage, requiring urgent decompressive surgery. Histological study of the lesion raised the possibility of myopericytoma. This was confirmed 16 months later when complete vertebrectomy was performed due to severe epidural propagation of the recurring tumor. No further recurrence occurred in next the two years. CONCLUSIONS: Rare angio-proliferative tumors, like benign metastasizing leiomyoma and myopericytoma radiologically may resemble aggressive vertebral hemangiomas of the spine. Unlike hemangiomas, such tumors require radical removal due to their likely recurrence. As imaging studies may not be able to completely exclude such pathologies, bone biopsy and thorough histopathological studies are warranted prior to the therapeutic decision.

[Frequency of adjacent vertebral fractures following percutaneous vertebroplasty]. / Szomszédos csigolyatörések elofordulása percutan vertebroplastica után.

INTRODUCTION AND AIMS: Percutaneous vertebroplasty (PVP) proved to be very effective in the treatment of pain caused by osteoporotic vertebral compression fractures. A certain proportion of patients, however, suffer a new fracture after treatment. Our purpose was to analyze the frequency of new fractures, and to estimate the causative role of PVP in the treated population. METHODS: The retrospective study reviewed all consecutive patients treated with PVP for osteoporotic compression fractures during a 5.5 years period. The study group comprised those patients, who suffered a new fracture during the follow up. The primary endpoint was the frequency of new fractures. The secondary endpoint was the occurrence of new fractures in a timeframe of 90 days after treatment that were adjacent to the previously treated segments. The causative role of PVP was estimated to be the highest in this subgroup. RESULTS: Altogether 396 consecutive patients were treated with PVP for osteoporotic compression fractures. Mean age was 68+11 years, and 23% of the population was male. The study group comprised 73 patients (18.4%). In this subgroup the patients had an average of 3.8 vertebral fractures. After PVP, adjacent fractures were significantly more likely, than distal fractures. Altogether 44 patients (11% of the entire population) suffered an adjacent fracture in 90 days after PVP. In this group there were significantly less male patients as compared to the entire population. CONCLUSIONS: After PVP almost every fifth patient is at risk for developing a new fracture, however, it is likely to be related to the vertebral augmentation in every tenth subject only. Female patients with severe osteoporosis are probably facing the highest risk for developing new fractures.

Vertebral artery dissection as an extremely rare cause of spinal epidural hematoma: case report and review of the literature.

OBJECTIVE: To present a patient with a cervico-thoracic ventrally located epidural hematoma caused by dissection and subsequent bleeding of the cervical portion of the vertebral artery. SUMMARY AND BACKGROUND DATA: Non traumatic epidural hematoma is a rare entity. The etiology usually is not clarified: a venous origin is usually suspected although an arterial source is also possible. CLINICAL REPORT: A 32-year-old woman presented with a ventrally located cervico-thoracic epidural hematoma caused by non traumatic dissection and dissecting aneurysm rupture of the cervical portion of the vertebral artery. The dissection was demonstrated by magnetic resonance imaging and digital subtraction angiography. The patient had no neurological symptoms and was treated by conservative methods. Follow up imaging showed healing of the vertebral artery and resorption of the epidural hematoma. CONCLUSION: Dissection of the cervical portion of the vertebral artery with subsequent perivascular bleeding is not well recognized as a possible cause of a spinal epidural hematoma. Even though this entity and the underlying cause may be rare, we suggest a vigilant search for vertebral artery injury in cases of ventrally located cervical and upper thoracic epidural hematoma.

FDG, MET or CHO? The quest for the optimal PET tracer for glioma imaging continues.

This Practice Point commentary discusses a study by Kato et al. that assessed the usefulness of three PET tracers--(11)C-methionine (MET), (18)F-fluorodeoxyglucose, and (11)C-choline--for the metabolic evaluation of gliomas. The authors measured the ratio of tumor uptake to normal brain uptake (T/N ratio), with the frontal cortex as reference region, and analyzed the correlations between tracer uptake and tumor grade, type, and proliferation activity. Whereas all three tracers showed a similar correlation between the T/N ratio and tumor grade in astrocytic and oligodendroglial tumors, MET proved to be the most user-friendly marker in all gliomas as it enables the straightforward localization of 'hot lesions' and provides outstanding quantitative metabolic parameters. Here we highlight a few methodological issues arising from Kato et al.'s study and, consequently, we urge the PET community to reach a consensus on an objective approach towards the evaluation of PET tracers in the field of neuro-oncology.

Impact of aneurysmal geometry on intraaneurysmal flow: a computerized flow simulation study.

INTRODUCTION: This study was performed to assess the effect of aneurysm geometry on parameters that may have an impact on the natural history of intracranial aneurysms, such as intraaneurysmal flow pressure and shear stress. METHODS: Flow was simulated in 21 randomly selected aneurysms using finite volume modeling. Ten aneurysms were classified as side-wall aneurysms, with either single-sided or circumferential involvement of the parent artery wall, and 11 as bifurcation aneurysms (symmetric or asymmetric), with an axis either perpendicular or parallel to the parent artery. The flow patterns were classified as either jet or vortex types (with regular or irregular vortex flow). Pressures and shear stresses were characterized as evenly or unevenly distributed over the aneurysm wall and neck. RESULTS: All side-wall and four of the bifurcation aneurysms with a perpendicular axis had a vortex type flow pattern and seven bifurcation aneurysms with a parallel axis (four symmetric and two asymmetric) had a jet flow pattern. Jet type flow was associated with an uneven pressure distribution in seven out of seven aneurysms. Vortex type flow resulted in an even pressure distribution in five out of six aneurysms with an irregular flow pattern and six out of eight with a regular flow pattern. No firm relationship could be established between any geometrical type and shear stress distribution. Only 1 of 14 aneurysms with a perpendicular axis, but 4 of 7 aneurysms with a parallel axis, had ruptured. CONCLUSION: Aneurysm geometry does have an impact on flow conditions. Aneurysms with a main axis parallel to the parent artery have a tendency to have a jet flow pattern and uneven distribution of unsteady pressure. These aneurysms may have a higher rate of rupture as than those with a main axis perpendicular to the parent artery.

Long-term results and late complications after intracavitary yttrium-90 colloid irradiation of recurrent cystic craniopharyngiomas.

OBJECTIVE: Data were analyzed to assess the value of stereotactically applied intracystic colloidal yttrium-90 (YTx) for the treatment of recurrent cystic craniopharyngiomas during a 30-year period. METHODS: This article compares data from 73 YTx procedures in 60 patients between 1975 and 2006. The cumulative beta dose aimed at the inner surface of the cyst wall was 300 Gy. RESULTS: After YTx, the initial cyst volumes decreased an average of 79%. In 47, the reduction was more than 80%; in 27 of them, the cyst disappeared completely within 1 year. The mean survival after YTx was 9.4 years (range, 0.7-30 yr). Actuarial survival rates at 5, 10, 15, 20, 25, and 30 years were 81, 61, 45, 18, 2, and 0%, respectively. Late complications of YTx were related to the anatomic localization of the cyst, either presellar and retrosellar, e.g., a presellar (prechiasmatic/suprasellar) localization caused neuro-ophthalmological complications in 5.8% and internal carotid artery injury in 1.6%. The treatment of retrosellar (retrochiasmatic, suprasellar) tumors occasionally induced hypothalamic and/or pontomesencephalothalamic damage obviously by untoward radiation to the so-called perforating arteries. This occurred in 3.2% of these latter patients. CONCLUSION: Despite sporadic complications, intracavitary YTx irradiation is a valuable treatment alternative for craniopharyngioma cysts, sometimes as part of a multimodality management in these tumors, especially in precarious surgical cases.

The role of microglia/macrophage system in the tissue response to I-125 interstitial brachytherapy of cerebral gliomas.

OBJECTIVE: To study histopathologic changes and the role of the microglia/macrophage cell in the therapeutic effect of I-125 interstitial brachytherapy on the cerebral gliomas. METHODS: Out of a series of 60 cases with cerebral astrocytomas and other brain tumors treated with I-125 interstitial brachytherapy, autopsy materials were available in ten cases 0.75 and 60 months after irradiation. The patients were treated with the maximum dosage (60 Gy) on the tumor periphery. Besides the routine hematoxylin-eosine and Mallory's PTAH trichrome staining, immunohistochemical reactions were carried out for CD15, CD31, CD34, CD45, CD68, CPM, HAM56 and HLR-DR antigens on paraffin sections to study immunologic phenotypic characteristics of the reaction cell population around gliomas after I-125 treatment. RESULT: One month after irradiation, a necrotic zone developed around the I-125 seeds within the 72 Gy isodose curve. Histologically, there was a fresh coagulation necrosis in the center of the lesion. Reactive zone has not yet developed but scattered interstitial and perivascular CD68 positive macrophages were present in the surrounding brain tissues. Six months after the I-125 isotope treatment, a reactive zone developed: a microglial rim around the necrosis tissue, and a broad area of proliferating vessels and glial fibrillary acidic protein (GFAP) positive astroglial cells which contained CD68 positive activated microglial and macrophage cells. Fifty-four months after I-125 interstitial irradiation, the necrotic center became colliquative and cystic. The microglial rim was replaced by round end stage (HLR-DR and CD31 positive) macrophages. The reactive zone was characterized by astrocytic gliosis but vascular proliferation and macrophages were lacking. CONCLUSION: Results of the present immunohistochemical study suggest that the early lesions are characterized by migrating macrophages apparently concerned with the removal of necrotic debris. The established phase of reactive zone around the necrotic center is characterized by a narrow inner rim of microglial accumulation and a broad outer area characterized by astrocytic gliosis, vascular proliferation, activated microglia and infiltration by macrophages. In the burned-out phases of I-125 interstitial brachytherapy of gliomas, the necrosis undergoes liquefaction and the microglial rim is replaced by astrocytic gliosis which can be considered as equivalent to the scar tissue formed around necrosis outside the central nervous system.

Introduction: the contribution of pathology to radiosurgery.

The term radiosurgery signifies any kind of application of ionizing radiation energy, in experimental biology or clinical medicine, aiming at the precise and complete destruction of chosen target structures containing healthy and/or pathological cells, without significant concomitant or late radiation damage to adjacent tissues. The goal of this study is to explore the short- and long-term pathophysiological effects of high-dose focused irradiation on neural tissue and its pathologies with histological, electron-microscopical tissue culture and biological-biochemical methods. Radiosurgical pathology focuses its scope and microscope on tissue, cellular, genetic and molecular changes in the human organism and experimental animals, or in cell lines and other in vitro experiments, generated by the ionizing radiation delivered from radiosurgical devices.

Pathological considerations to irradiation of cavernous malformations.

Stereotactic radiosurgery is a controversial treatment modality in the management of cerebral cavernous malformations (CVMs). Systematic pathological studies of irradiated specimens probably could help to resolve the controversy. Light microscopic investigation of a surgically resected thalamic CVM 1 year after 40-Gy irradiation revealed endothelial cell destruction in the cavernous channels, and marked fibrosis with scar tissue formation in the connective stroma of the lesion. These histopathological findings were similar to those described in arteriovenous malformations after Gamma Knife surgery, and suggest that the ionizing effect of radiation energy evokes vascular and connective tissue stroma changes in CVMs as well.

Stereotactic intracavitary irradiation of cystic craniopharyngiomas with yttrium-90 isotope.

The authors analyzed data from nearly 30-year follow-up period to assess the value of intracavitary irradiation with stereotactically implanted beta-emitting radioisotope yttrium- 90 (90Y) silicate colloid for the treatment of cystic craniopharyngiomas. Seventy-three cysts in 60 patients were selected for retrospective analysis. The cumulative dose aimed at the inner surface of the cyst wall was 300 Gy. An average of 79% (mean 88.3%) shrinkage of the initial cyst volume was observed. In 47 cysts, the reduction was more than 80%, and the cyst disappeared totally in 29 out of those 47 cases, usually within a year. Mean survival duration after intracavitary irradiation was 9.4 years. Neuroophthalmological prognosis was only favorable when the optic disc was normal or nearly normal at the time of the treatment. In the presence of preexisting optic atrophy, visual damage proved to be irreversible. The long-term results support the view that intracavitary 90Y irradiation is a noninvasive and effective method for the treatment of craniopharyngioma cysts. Because of the mean penetration pathway of beta irradiation is 3.6mm in the soft tissues (maximum 11 mm) it cannot influence the solid part of the tumor; therefore, the best result can be expected in solitary cysts.

Tissue response to iodine-125 interstitial brachytherapy of cerebral gliomas.

The purpose of this study was to investigate histopathological changes and the role of the microglia/macrophage cell system in the therapeutic effect of iodine-125 (125I) interstitial brachytherapy on cerebral gliomas. Out of a series of 60 cases harboring cerebral astrocytomas and other brain tumors treated with 125I interstitial brachytherapy, autopsy material was available in 10 cases between 0.75 and 60 months after irradiation. The patients were treated with 60-Gy maximum doses at the tumor periphery. Besides the routine HE and Mallory's PTAH trichrome staining, immunohistochemical reactions were carried out for CD15, CD31, CD34, CD45, CD68 (PG-M1), CPM, HAM 56 and HLA-DR antigens to study immunological characteristics of the reactive cell population around gliomas after 125I treatment. The present immunohistochemical study demonstrated that the early lesions following 125I interstitial brachytherapy of gliomas are characterized by migrating macrophages apparently concerned with the removal of necrotic debris. The established phase of reactive zone around the necrotic center disclosed a narrow inner rim of microglial accumulation, and a broad outer area consisting of astrocytic gliosis, vascular proliferation, activated microglia and infiltration by macrophages. In the burned-out phase, the necrosis undergoes liquefaction, the microglial rim is replaced by end-stage macrophages, and the reactive zone is transformed into astrocytic gliosis, which can be considered as equivalent to scar tissue formed around necrosis outside of the central nervous system.

[Radiotherapy of pituitary tumours]. / A hypophysisdaganatok radioteráipiáija.

In this article, the role of conventional radiotherapy and radiosurgery in the management of pituitary tumors is discussed. After a brief review about the mechanism of action and different techniques of irradiation therapy, the therapeutic effectiveness and side effects are analysed in the various types of pituitary tumors. Conventional fractionated radiotherapy has long been used to control growth and/or hormonal secretion of residual or recurrent pituitary tumors. Nevertheless, there is still a controversy concerning patient selection for radiotherapy, because several potentially significant side effects including hypopituitarism may develop. Stereotactic radiosurgical methods may have several advantages over conventional radiotherapy; they can be applied, for example, in patients with residual or recurrent pituitary tumors who had previously received conventional radiotherapy. However, long-term follow-up data with these relatively new techniques are still limited.

Optimization of semi-quantification in metabolic PET studies with 18F-fluorodeoxyglucose and 11C-methionine in the determination of malignancy of gliomas.

The treatment of the glioma patient depends on the nature of the lesion and on the aggressiveness of the tumor. The management of gliomas continues to be a challenging task, because morphological neuroimaging techniques do not always differentiate them from nontumoral lesions or high grade tumors from low grade lesions. Positron Emission Tomography (PET) offers the possibility of the in vivo quantitative characterization of brain tumors. Despite decades of useful application of PET in the clinical monitoring of gliomas, no consensus has been reached on the most effective image analysis approach for providing the best diagnostic performance under heavy-duty clinical diagnostic circumstances. The main objective of the present study was to find and validate optimal semi-quantitative search strategies for metabolic PET studies on gliomas, with special regard to the optimization of those metabolic tracer uptake ratios most sensitive in predicting histologic grade and prognosis. 11C-Methionine (11C-Met, n = 50) and/or 18F-Fluorodeoxyglucose (18F-FDG, n = 33) PET measurements were performed in 59 patients with primary and recurrent brain gliomas (22 high grade and 37 low grade tumors) in order to correlate the biological behavior and 11C-Met/18F-FDG uptake of tumors. Data were analyzed by region-of-interests (ROI) methods using standard uptake value calculation. Different ROI defining strategies were then compared with each other for two of the most commonly used metabolic radiotracers, 18F-FDG and 11C-Met, in order to determine their usefulness in grading gliomas. The results were compared to histological data in all patients. Both ANOVA and receiver operating characteristic (ROC) analysis indicated that the performance of 18F-FDG was superior to that of 11C-Met for most of the ratios. 18F-FDG is therefore suggested as the tracer of choice for noninvasive semi-quantitative indicator of histologic grade of gliomas. 11C-Methionine has been suggested as a complimentary tracer, useful in delineating the extent of the tumor. The best diagnostic performance was obtained by calculating the ratio of the peak 18F-FDG uptake of the tumor to that of white matter (p < 0.001; ANOVA). This metabolic tracer uptake ratio is therefore suggested as an easily obtained semi-quantitative PET indicator of malignancy and histological grade in gliomas.

Erdheim-Chester's disease of the heart: a diagnostic conundrum and collision with the same mass in the orbit.

Erdheim-Chester's disease is a rare multisystem xanthogranulomatosis, afflicting the skeletal system with the occasional involvement of soft tissues. We delineate an unusual case of a cardiac variant of Erdheim-Chester's disease presenting with pericardial effusion and as a collision with a synchronous orbital manifestation. We describe our diagnostic pathway and propose a novel treatment option involving nonsteroidal anti-inflammatory drugs. The role of cyclo-oxygenase in the disease process and inhibition thereof by NSAIDs is hypothesized and discussed.