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Stefan Wolfsberger

Publications and source records attributed to Stefan Wolfsberger.

16 recordsLinked to original sources
PubMed2006

Gamma-knife radiosurgery for cranial base meningiomas: experience of tumor control, clinical course, and morbidity in a follow-up of more than 8 years.

OBJECTIVE: Surgical resection of cranial base meningiomas is often limited owing to involvement of crucial neural structures. Within the last 2 decades Gamma Knife radiosurgery (GKRS) has gained increasing importance as an adjunct treatment after incomplete resection and as an alternative treatment to open surgery. However, reports of long-term results are still sparse. We therefore performed this study to analyze the long-term results of GKRS treatment of cranial base meningiomas, following our previously published early follow-up experience. METHODS: A retrospective analysis of the medical files for Gamma Knife and surgical treatments, clinicoradiological findings, and outcome was carried out focusing on tumor control, clinical course, and morbidity. RESULTS: Between 1992 and 1995, we treated 36 patients with cranial base meningiomas using GKRS (male:female ratio, 1:5; mean age, 59 yr; range, 44-89 yr). Twenty-five patients were treated with GKRS after open surgery, and 11 patients received GKRS alone. Tumor control, neurological outcomes, and adverse effects were analyzed after a long-term follow-up period (mean, 103 mo; range, 70-133 mo) and compared with our previous results after an early follow-up period (mean, 48 mo; range, 36-76 mo). Control of tumor growth was achieved in 94% of patients. Compared with the early follow-up period, the late neuroradiological effects of GKRS on cranial base meningiomas were continuing tumor shrinkage in 11 patients (33%), stable tumor size in 20 patients (64%) and tumor progression in two meningiomas (6%). The neurological status improved in 16 patients (44%), remained stable in 19 patients (52%), and deteriorated in one patient (4%). Adverse side effects of GKRS were found only during the early follow-up period. CONCLUSION: Our data confirm that GKRS is not only a safe and effective treatment modality for cranial base meningiomas in short-term observation, but also in a mean long-term follow-up period of more than 8 years. Tumor shrinkage and clinical improvement also continued during the longer follow-up period.

Aged↗
PubMed2006

Advanced virtual endoscopy for endoscopic transsphenoidal pituitary surgery.

OBJECTIVE: Virtual endoscopy (vE) is the navigation of a camera through a virtual anatomical space that is computationally reconstructed from radiological image data. Inside this three-dimensional space, arbitrary movements and adaptations of viewing parameters are possible. Thereby, vE can be used for noninvasive diagnostic purposes and for simulation of surgical tasks. This article describes the development of an advanced system of vE for endoscopic transsphenoidal pituitary surgery and its application to teaching, training, and in the routine clinical setting. METHODS: The vE system was applied to a series of 35 patients with pituitary pathology (32 adenomas, three Rathke's cleft cysts) operated endoscopically via the transsphenoidal route at the Department of Neurosurgery of the Medical University Vienna between 2004 and 2006. RESULTS: The virtual endoscopic images correlated well with the intraoperative view. For the transsphenoidal approach, vE improved intraoperative orientation by depicting anatomical landmarks and variations. For planning a safe and tailored opening of the sellar floor, transparent visualization of the pituitary adenoma and the normal gland in relation to the internal carotid arteries was useful. CONCLUSION: According to our experience, vE can be a valuable tool for endoscopic transsphenoidal pituitary surgery for training purposes and preoperative planning. For the novice, it can act as a simulator for endoscopic anatomy and for training surgical tasks. For the experienced pituitary surgeon, vE can depict the individual patient's anatomy, and may, therefore, improve intraoperative orientation. By prospectively visualizing unpredictable anatomical variations, vE may increase the safety of this surgical procedure.

Adult↗
PubMed2005

Survivin expression in intracranial ependymomas and its correlation with tumor cell proliferation and patient outcome.

Survivin expression has been described as prognostic factor in various tumor types and has been shown to correlate with cytologic anaplasia in ependymoma. We immunohistochemically studied survivin expression and its association with Ki-67 and topoisomerase IIalpha (TIIalpha) expression and outcome in 63 patients with intracranial ependymoma. Survivin is expressed in a fraction of nuclei of tumor and endothelial cells including mitotic figures. Survivin indices range from 0.6% to 43.2% and correlate with Ki-67 and TIIalpha indices. On average, 62.86% of Ki-67-expressing tumor cell nuclei coexpress survivin, whereas 92.2% of survivin-expressing nuclei coexpress Ki-67. High survivin, Ki-67, and TIIalpha indices univariately correlated with an unfavorable outcome. In multivariate analysis, only the Ki-67 index remained an independent prognostic factor. In ependymoma, survivin is expressed in a subset of proliferating cells. High survivin expression is associated with poor patient outcome. However, the Ki-67 index is a more accurate prognostic marker than the survivin or TIIalpha index.

Adolescent↗
PubMed2004

Vascularization and expression of hypoxia-related tissue factors in intracranial ependymoma and their impact on patient survival.

We investigated angiogenic patterns and expression of hypoxia-related tissue factors and their prognostic impact in 100 cases of intracranial ependymoma. Angiogenic patterns were evaluated by anti-CD34 immunolabeling. Hypoxia-related factors carbonic anhydrase 9 (CA9) and hypoxia-inducible factor 1 alpha (HIF-1alpha) were visualized by immunohistochemistry, and vascular endothelial growth factor (VEGF) mRNA by in situ hybridization. Expression patterns of VEGF and CA9 are similar with regard to distribution (perinecrotic) and extent. HIF-1alpha expression occurs in a significantly smaller fraction of cases and only in a few tumor cells without clear association with necrosis. Expression of VEGF and CA9, but not HIF-1alpha, is associated with a bizarre angiogenic subtype. Combined expression of two or three hypoxia markers (high hypoxia score) associates with presence of necrosis, high proliferation index, bizarre vascular pattern, and increased cellularity. Univariate analysis indicated that patients with high hypoxia score had significantly shorter survival. On multivariate analysis, only proliferation index and extent of resection remained independent predictive factors. We conclude that bizarre vascular pattern, necrosis and high hypoxia score are frequently detectable in intracranial ependymoma, but seem less important for patient outcome than tumor cell proliferation.

Adolescent↗
PubMed2004

Progesterone-receptor index in meningiomas: correlation with clinico-pathological parameters and review of the literature.

For recurrent and untreatable meningiomas alternative therapies, such as anti-progesterone treatment, have been sought. However, the few clinical studies have not determined progesterone receptor (PgR) expression in most cases, and studies correlating quantitative PgR expression (PgR index) with clinico-pathological variables are scarce. The aim of our study was to assess the PgR indices in a consecutive series of meningiomas and correlate these values with clinico-pathological parameters. We analyzed immunohistochemically 82 consecutive meningioma specimens (73 primary and nine recurrent tumors) for PgR and Ki-67 antigen (MIB-1). The male/female ratio was 1:1.7, and median age at the time of surgery was 57 years (range 29-77 years). The series comprised 55 grade I (subtyped as 36 meningothelial, seven fibrous, nine transitional, two psammomatous, and one angiomatous), 23 grade II, and one grade III meningiomas. Nuclear immunostaining for PgR was positive in 56 meningioma specimens (71%). PgR index was 21.4+/-2.8% (mean +/- SE; range 0-79%). Significantly higher expression was found in male patients in the age group <50 years than in those > or = 60 years and in grade I meningothelial meningiomas than in fibrous and transitional subtypes. There was a trend to lower PgR indices in non-benign meningiomas. Cell proliferation rate (MIB-1 index) was 4.4 +/- 0.4% (mean +/- SE; range 0.3-15.4%). Significantly higher MIB-1 indices were found in male than female patients,in recurrent than primary and in grade II than grade I meningiomas. We observed a trend to higher PgR indices in meningiomas with MIB-1 index <5%. In sum, the highest PgR index in our series was observed in patients under the age of 50 years with WHO grade I meningiomas of the meningothelial subtype and low cell proliferation indices. If hormonal therapy has a direct action on the PgR, these patients should respond best to anti-progesterone treatment. We conclude that PgR index is variable in meningioma, depending on clinical parameters and histopathological features. Stratification of anti-progesterone therapy trials on the basis of PgR index should be considered.

Adult↗
PubMed2004

Microvessel density is not crucial for scintigraphic visualization of brain tumors using 99mTc-MIBI.

Functional imaging of brain tumors assists biopsy localization, therapy monitoring, and differentiating tumor recurrence from radiation necrosis. Tumor vascularization is a strong prognostic predictor in solid tumors and also a key factor of tracer uptake. However, the relationship of brain tumor vascularization and functional imaging has not yet been investigated sufficiently so far. In the present study, we correlated histologically assessed microvessel density as an objective parameter for brain tumor vascularization with imaging data. Four male patients were studied. After 99mTc-MIBI scintigraphy, all patients had a MRI within 2 weeks. Histology showed microcystic astrocytoma, glioblastoma (n = 2), and anaplastic oligodendroglioma, respectively. Microvessel density was lowest in the microcystic astrocytoma, medium in the glioblastomas, and highest in the anaplastic oligodendroglioma. Scintigraphy visualized only the glioblastomas, but not the microcystic astrocytoma or oligodendroglioma. Our data showed no correlation between tumor microvessel density and 99mTc-MIBI scintigraphy. Thus, we conclude that scintigraphic visualization of brain tumors is not strictly dependent on tumor vascularization.

Adult↗
PubMed2004

Ki-67 immunolabeling index is an accurate predictor of outcome in patients with intracranial ependymoma.

Histopathologic grading of ependymomas is considered unreliable in terms of outcome prediction. Quantification of tumor cell proliferation may be useful for outcome prediction. We analyzed prognostic and predictive values of tumor cell proliferation rates using anti-Ki-67 antigen (MIB-1 antibody) and anti-topoisomerase-IIalpha (Topo-IIalpha) immunolabeling on tumor samples of 103 consecutive ependymoma patients 0.1 to 74.4 years of age. In this patient cohort, the following clinical and histopathologic parameters showed significant correlation with overall survival on univariate analysis: extent of resection, use of an operating microscope, radiologic imaging with computed tomography and/or magnetic resonance imaging, radiotherapy, tumor size (cutoff 3 cm), WHO grade, presence of tumor necrosis, increased cellularity, microvascular proliferation, and low/high Ki-67 and Topo-IIalpha indices (cutoff 20.5% and 9.4%, respectively). On multivariate analysis, incomplete resection and high Ki-67 index remained independent factors of adverse patient outcome. In Kaplan-Meier survival analysis, low (<20.5%) or high (> or = 20.5%) Ki-67 indices predicted favorable (> or = 5 years) or unfavorable (<5 years) patient outcome at 79% and 70%, respectively. We conclude that Ki-67 immunolabeling index is an independent prognostic factor and accurate predictor of outcome in patients with intracranial ependymoma. Thus, assessment of Ki-67 index in intracranial ependymoma is useful for outcome prediction in the routine diagnostic setting.

Adolescent↗
PubMed2004

Application of three-tesla magnetic resonance imaging for diagnosis and surgery of sellar lesions.

OBJECT: The aim of this study was to determine the value of high-field magnetic resonance (MR) imaging for diagnosis and surgery of sellar lesions. METHODS: High-field MR images were obtained using a 3-tesla unit with emphasis on sellar and parasellar structures in 21 patients preoperatively to delineate endo-, supra-, and parasellar anatomical structures. Special attention was given to the medial border of the cavernous sinus and possible invasion of a sellar tumor therein, and to assessing the application of high-resolution images during intraoperative neuronavigation. The 3-tesla MR images were compared with the standard MR images already obtained and with intraoperative findings. Anatomical structures were studied in all 42 cavernous sinuses; in 32 of them comparisons with intraoperative findings were possible. The medial cavernous sinus border was rated intact in 53% on standard MR images, in 72% on 3-tesla MR images, and in 81% intraoperatively. With a positive correlation to surgical findings on 84% of 3-tesla MR images compared with 59% of standard MR images, a sensitivity of 83% compared with 67%, and a specificity of 84% compared with 58% (p = 0.016, McNemar test), 3-tesla MR imaging was superior for predicting tumor invasion through the medial cavernous sinus border. Although no difference was noted in delineation of the medial, superior, and inferior compartments, there was a better delineation of the lateral cavernous sinus compartment with 3-tesla MR imaging. This compartment was clearly visible on 40 sides (95%) on 3-tesla MR images compared with 34 sides (81%) on standard MR images. Identification of the cavernous sinus segments of the third, fourth, fifth (V1 and V2), and sixth cranial nerves was improved using high-resolution 3-tesla imaging compared with standard MR imaging. A mean of four cranial nerves was found as hypointense spots (range two-five spots) on 3-tesla MR imaging compared with a mean of three (range zero-four spots) on standard MR imaging. After addition of contrast agents, the anterior pituitary gland was found to be highly intense on 78% of T1-weighted three-dimensional magnetization-prepared rapid acquisition gradient-echo (MPRAGE) 3-tesla MR images compared with 73% of standard T1-weighted MR images. The optochiasmatic system displayed increased intensity on pre-contrast T1-weighted MPRAGE 3-tesla compared with standard T1-weighted MR images; it was hyperintense on 76% of 3-tesla compared with 15% of standard MR images, which was helpful for its delineation from suprasellar pituitary and tumor structures. Intraoperative navigation guided by fusion of 3-tesla MR images and computerized tomography (CT) scans was performed in seven patients. Whereas CT scanning was used during the transsphenoidal approach to depict the nasal bone structures, 3-tesla MR imaging was particularly useful for the visualization of parasellar tumor extension during microsurgical and/or endoscopic resection. CONCLUSIONS: Due to its higher resolution, 3-tesla MR imaging was found to be superior to standard MR imaging for the delineation of parasellar anatomy and tumor infiltration of the cavernous sinus, and this modality provided improved imaging for intraoperative navigation.

Adenoma↗
PubMed2003

Multiple supratentorial epidural haematomas after posterior fossa surgery.

Postoperative epidural haematoma distant to a site of craniotomy is a rare but possibly hazardous complication. We report a 31-year-old female who presented with a history of chronic hydrocephalus due to fourth-ventricular plexus papilloma. Following resection of the posterior fossa tumour with intraoperative placement of a ventricular drainage, she consecutively developed four supratentorial epidural haematomas at different locations, all necessitating evacuation. The clinical manifestations ranged from subtle neurological deficits to signs of tentorial herniation; the ultimate outcome was complete recovery. Rapid tapering of CSF pressure after long-standing hydrocephalus and clotting disorders could be implicated as causative factors. We stress the importance of early postoperative CT scan and optimal management of ventricular pressure and coagulation status to detect and prevent this possibly life-threatening complication.

Adult↗
PubMed2003

MR contrast agent at high-field MRI (3 Tesla).

Tumor-to-brain contrast after gadolinium administration using MP-RAGE and T1-SE scans in patients with primary and secondary brain tumors was significantly higher at 3 T than at 1.5 T. The subjective assessment of cumulative triple-dose 3 Tesla images obtained the best results in the detection of brain metastases compared with other sequences followed by 1.5 T cumulative triple-dose enhanced images. In macroadenomas of the hypophysis, contrast-enhanced 3 T MRI was superior to standard MRI in the diagnosis of cavernous sinus infiltration and in visualization of cranial nerves within the cavernous sinus. Due to higher spatial resolution, contrast-enhanced MR venography at 3 T showed more details in and around tumors than at 1.5 T, additionally enhanced by stronger susceptibility weighting and higher signal-to-noise ratio at 3 T. In summary, administration of gadolinium-based contrast agent produces higher contrast between tumor and normal brain at 3 T than at 1.5 T, helps to detect more cerebral metastases at 3 T versus 1.5 T in single and cumulative triple dose, improves the evaluation of macroadenomas of the hypophysis, and makes MR venography at 3 T clinically attractive with increase in spatial resolution within the same measurement time, thus providing more detailed information.

Adenoma↗
PubMed2003

Prone position in subarachnoid hemorrhage patients with acute respiratory distress syndrome: effects on cerebral tissue oxygenation and intracranial pressure.

OBJECTIVE: To analyze the effect of prone position on cerebral perfusion pressure and brain tissue oxygen partial pressure in subarachnoid hemorrhage patients with acute respiratory distress syndrome (ARDS). DESIGN: Clinical study with retrospective data analysis. SETTING: Neurosurgical intensive care unit of a primary level university hospital. PATIENTS: Sixteen patients treated for intracranial aneurysm rupture with initial Hunt and Hess grade III or worse who developed ARDS within 2 wks after the bleeding. INTERVENTIONS: Routine neurosurgical intensive care treatment for subarachnoid hemorrhage and posthemorrhagic vasospasm including cerebral monitoring with continuous intracranial pressure and brain tissue oxygen partial pressure recordings. MEASUREMENTS AND MAIN RESULTS: Hemodynamics, arterial oxygenation, ventilatory setting, intracranial pressure, cerebral perfusion pressure, and brain tissue oxygen partial pressure in the supine as well as in the prone position were analyzed and compared. A significant increase in Pao(2) from 97.3 +/- 20.7 torr (mean +/- sd) in the supine position to 126.6 +/- 31.7 torr in the prone position was joined by a significant increase in brain tissue oxygen partial pressure from 26.8 +/- 10.9 torr to 31.6 +/- 12.2 torr (both p <.0001), whereas intracranial pressure increased from 9.3 +/- 5.2 mm Hg to 14.8 +/- 6.7 mm Hg and cerebral perfusion pressure decreased from 73.0 +/- 10.5 mm Hg to 67.7 +/- 10.7 mm Hg (both p <.0001). CONCLUSIONS: The beneficial effect of prone positioning on cerebral tissue oxygenation by increasing arterial oxygenation appears to outweigh the expected adverse effect of prone positioning on cerebral tissue oxygenation by decreasing cerebral perfusion pressure in ARDS patients.

Adult↗
PubMed2003

[Imaging of tumors of the pituitary gland].

Macrotumors of the sella region usually involve the suprasellar and less commonly the parasellar space. The suprasellar extension of pituitary adenoma, meningeoma, craniopharyngioma, and hypothalamic or chiasmatic glioma count for the most frequent neoplastic entities. In macroadenomas of the pituitary gland invasion of parasellar spaces may occur in 6-10%. Imaging techniques are directed to increase the likelihood of surgical cure and to detect aggressive tumour invasion into surrounding tissues. A dedicated classification basing on indirect MRI signs of tumour extension has been established. With high-resolution high-field (3T) MRI the sella region may be displayed to provide better information compared to lower field strengths.

Adenoma↗
PubMed2003

[Pituitary adenomas: neurosurgical treatment].

Due to their diversity, pituitary adenomas represent an interdisciplinary therapeutic challenge in regard to endocrinology, radiology and neurosurgery. Advanced radiological methods such as magnetic resonance imaging (MRI) and the possibility of three-dimensional reconstruction have profoundly improved surgical planning and intraoperative neuronavigation. With the application of modern surgical techniques like endoscope-assisted microsurgery or pure endoscopic surgery further improvements in the treatment of pituitary adenomas at difficult locations can be expected. Major prognostic factors predicting surgical outcome are extension of the adenoma and invasivity into adjacent structures. Both may be perfectly visualized by high-resolution MRI. The proliferation marker MIB-1 as a parameter of growth-rate and invasivity of pituitary adenomas provides information for postoperative management in terms of additional treatment and follow-up imaging. The current management of pituitary adenomas is discussed according to the different therapeutic options available and new developments are presented.

Adenoma↗
PubMed2002

Anatomical landmarks for image registration in frameless stereotactic neuronavigation.

OBJECTIVE: Frameless stereotactic navigation devices require preoperative application of skin markers (SM) and planning radiography, which limits their even wider use. Therefore, we prospectively studied the applicability and accuracy of anatomic "natural" markers (NM) for image registration. METHODS: The accuracy of NM was evaluated in 26 patients operated on in the supine (n=24) or sitting (n=2) position, either by comparison to our standard navigation protocol using SM and planning radiography or by the deviation of anatomic landmarks using a routine diagnostic radiograph. In 21 cases, NM were compared to SM with planning radiography (computed tomography, or CT, in nine cases and magnetic resonance imaging, or MRI, in 12). The root mean square error (RMSE) of the registered volume was calculated by the Philips EasyGuide Neuro frameless stereotactic navigation system and compared between the two registration modalities. RESULTS: The mean RMSE was 3.2 mm+/-1.0 mm standard deviation using NM vs 2.9+/-1.0 mm using self-adhesive SM (P=0.13, Student's t-test). Computed tomography was slightly more accurate than MRI planning (mean RMSE 3.2 mm vs 3.3 mm). In three cases, diagnostic radiography (MRI) was used with a mean RMSE of 5.3 mm but acceptable intraoperative landmark correlation. CONCLUSION: Our pilot study demonstrates insignificant loss of registration accuracy using NM compared to SM. Additionally, the radiologic planning investigation and accuracy loss due to SM movement may be avoided.

Adolescent↗
PubMedDate not supplied

Advanced virtual endoscopic pituitary surgery.

Endoscopy has recently been introduced to endonasal transsphenoidal pituitary surgery as a minimally invasive procedure for the removal of various kinds of pituitary tumors. To reduce morbidity and mortality with this new technique, the surgeon must be well-trained and well-prepared. Virtual endoscopy can be beneficial as a tool for training, preoperative planning, and intraoperative support. This paper introduces STEPS, a virtual endoscopy system designed to aid surgeons in getting acquainted with the endoscopic view of the anatomy, the handling of instruments, the transsphenoidal approach, and challenges associated with the procedure. STEPS also assists experienced surgeons in planning a real endoscopic intervention by getting familiar with the individual patient anatomy, identifying landmarks, planning the approach, and deciding upon the ideal target position of the actual surgical activity. The application provides interactive visualization, navigation, and perception aids and the possibility of simulating the procedure, including haptic feedback and simulation of surgical instruments.

Algorithms↗