Walter Stummer - Academia.edu (original) (raw)

Papers by Walter Stummer

Journal of neurosurgery, Jan 24, 2017

OBJECTIVE Fluorescence guidance with 5-aminolevulinic acid (5-ALA) helps improve resections of ma... more OBJECTIVE Fluorescence guidance with 5-aminolevulinic acid (5-ALA) helps improve resections of malignant gliomas. However, one limitation is the low intensity of blue light for background illumination. Fluorescein has recently been reintroduced into neurosurgery, and novel microscope systems are available for visualizing this fluorochrome, which highlights all perfused tissues but has limited selectivity for tumor detection. Here, the authors investigate a combination of both fluorochromes: 5-ALA for distinguishing tumor and fluorescein for providing tissue fluorescence of adjacent brain tissue. METHODS The authors evaluated 6 patients who harbored cerebral lesions suggestive of high-grade glioma. Patients received 5-ALA (20 mg/kg) orally 4 hours before induction of anesthesia. Low-dose fluorescein (3 mg/kg intravenous) was injected immediately after anesthesia induction. Pentero microscopes (equipped either with Yellow 560 or Blue 400 filters) were used to visualize fluorescence. T...

Objective: The purpose of this study was to determine the relationship of [18F]fluoroethyl-L-tyro... more Objective: The purpose of this study was to determine the relationship of [18F]fluoroethyl-L-tyrosine (FET) uptake in gliomas using PET and intraoperative 5-aminolevulinic acid (5-ALA) fluorescence using neuronavigated biopsies during resection as a reference. FET PET provides improved imaging[for full text, please go to the a.m. URL]

Forum, 2013

ZusammenfassungHintergrundDie aktuelle Literatur legt nahe, dass die primäre und möglichst radika... more ZusammenfassungHintergrundDie aktuelle Literatur legt nahe, dass die primäre und möglichst radikale Resektion von Gliomen die Prognose der Patienten verbessert. Entscheidend ist, dass dabei keine wesentlichen neurologischen Defizite entstehen.ErgebnisseIn diesem Zusammenhang konnten innerhalb der letzten Jahre Techniken zur prä- sowie intraoperativen Erkennung von Tumorgewebe und Funktionen entwickelt bzw. verbessert werden, z. B. die Positronenemissionstomographie (PET) mit Aminosäuren, die funktionelle MRT, die navigierte Hirnstimulation, Fluoreszenzmethoden und der intraoperative Einsatz der MRT. Der vorliegende Beitrag gibt einen Überblick über aktuelle Entwicklungen in der Chirurgie hirneigener Tumoren.AbstractBackgroundThe current literature strongly supports radical resection of gliomas as the first line therapy to improve the prognosis of patients. However, it is important that no significant neurological deficits result.ResultsAccordingly, a number of pre- and intra-operative techniques for the identification of functionally intact brain and infiltrating tumor tissue have been developed, e.g., amino acid positron emission tomography, functional MRI, fluorescence techniques, navigated brain stimulation, and the intra-operative MRI. This review summarizes recent developments in the field of neurosurgery for the management of gliomas.

PloS one, 2016

Pituitary adenomas (PA), especially invasive ones, are often not completely resectable. Usage of ... more Pituitary adenomas (PA), especially invasive ones, are often not completely resectable. Usage of 5-aminolevulinic acid (5-ALA) for fluorescence guided surgery could improve the rate of total resection and, additionally, open the doors for photodynamic therapy (PDT) in case of unresectable or partially resected PAs. The aim of this study was to investigate the uptake of 5-ALA and the effect of 5-ALA based PDT in cell lines. GH3 and AtT-20 cell lines were incubated with different concentrations of 5-ALA, protoporphyrin IX (PPIX) fluorescence was measured by flow cytometry and fluorescencespectrometry. WST-1 assays were performed to determine the surviving fraction of cells after PDT. PPIX fluorescence intensities and PDT effect of the pituitary adenoma cells were compared to U373MG, a well-known glioblastoma cell line. Both cell lines showed a 5-ALA dependent intracellular PPIX fluorescence. Significant differences after 24hrs of incubation were observed in AtT-20 cells in comparison ...

RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren, 2007

Journal of Neuro-Oncology, 2007

Aminolevulinic acid (ALA)-mediated photodynamic therapy (PDT) may represent a treatment option fo... more Aminolevulinic acid (ALA)-mediated photodynamic therapy (PDT) may represent a treatment option for malignant brain tumors. We used a three-dimensional cell culture system, the C6 glioma spheroid model, to study acute effects of PDT and how they might be influenced by treatment conditions. Spheroids were incubated for 4 h in 100 microg/ml ALA in 5% CO(2) in room air or 95% O(2) with subsequent irradiation using a diode laser (lambda = 635 nm, 40 mW/cm(2), total fluence 25 J/cm(2)). Control groups were "laser only", "ALA only", and "no drug no light". Annexin V-FITC, a marker used for detection of apoptosis, propidium iodide (PI), a marker for necrotic cells and H 33342, a chromatin stain, were used for morphological characterization of PDT effects by confocal laser scanning and fluorescence microscopy. Hematoxylin-eosin staining and TdT-FragEL (TUNEL) assay were used on cryosections. Growth kinetics were followed for 8 days after PDT. PDT after incubation in 5% CO(2) provided incomplete cell death and growth delay in spheroids of >350 microm diameter. However, complete cell death and growth arrest occurred in smaller spheroids (<350 microm). Incubation in 95% O(2) with subsequent PDT resulted in complete cell death and growth arrest regardless of spheroid size. In incompletely damaged spheroids viable cells were restricted to spheroid centers. The rate of cell death in all control groups was negligible. Cell death was accompanied by annexin/PI costaining, but there was also evidence for annexin V-FITC staining without PI uptake. PDT of experimental glioma results in rapid and significant cell death that could be verified as acute necrosis immediately after irradiation. This effect depended on O(2) concentration and spheroid size.

Journal of Neurosurgery Pediatrics

Pineal cysts are benign and often asymptomatic intracranial entities. Occasionally they can lead ... more Pineal cysts are benign and often asymptomatic intracranial entities. Occasionally they can lead to neurological symptoms through growth or due to intracystic hemorrhage. The purpose of the current report is to describe their clinical characteristics and treatment options. In the current study, the authors illustrate the course of disease in 3 patients who developed neurological symptoms due to hemorrhage into a pineal cyst. Two of their patients had additional cerebral disease, and regular MR imaging examinations were conducted. This circumstance allowed documentation of growth and intracystic hemorrhage. After the occurrence of new neurological symptoms with severe headache, MR images showed a fluid-fluid interface due to intracystic hemorrhage. The third patient presented with acute triventricular hydrocephalus and papilledema due to aqueductal stenosis caused by intracystic hemorrhage. In all 3 cases, excision of the pineal cysts via an infratentorial/supracerebellar approach wa...

Brain tumor pathology, Jan 21, 2015

Telomerase reverse transcriptase (TERT) expression is a hallmark in tumorigenesis and upregulated... more Telomerase reverse transcriptase (TERT) expression is a hallmark in tumorigenesis and upregulated due to mutations and methylation of the human (h)TERT promoter. As mutations are rare but methylation is common in pituitary adenomas (PA), we determined promoter methylation and its clinical impact in 85 primary and 15 recurrent PA by methylation-specific PCR. 40 females (47 %) and 45 males (53 %) with a median age of 53 years harboring micro-, macro-, and giant adenomas in 12, 82, and 6 % were included (prolactinomas, corticotroph, somatotroph, gonadotroph, thyreotroph, plurihormonal, and null cell adenomas in 11, 18, 10, 29, 1, 10, and 21 %, respectively). In primary diagnosed tumors, methylation rate was 27 % and higher in males than in females (40 vs. 13 %, p = 0.001) after uni- and multivariate analyses. Methylation differed among PA subtypes (0-42 %, p = n.s.) and was not significantly correlated with tumor size, cavernous sinus invasion, or serum hormone levels. Ki67 labeling in...

Journal of neurosurgery, Jan 10, 2015

OBJECT Delayed ischemic neurological deficits (DINDs) and cerebral vasospasm (CVS) are responsibl... more OBJECT Delayed ischemic neurological deficits (DINDs) and cerebral vasospasm (CVS) are responsible fora poor outcome in patients with aneurysmal subarachnoid hemorrhage (SAH), most likely because of a decreased availability of nitric oxide (NO) in the cerebral microcirculation. In this study, the authors examined the effects of treatment with the NO donor molsidomine with regard to decreasing the incidence of spasm-related delayed brain infarctions and improving clinical outcome in patients with SAH. METHODS Seventy-four patients with spontaneous aneurysmal SAH were included in this post hoc analysis. Twenty-nine patients with SAH and proven CVS received molsidomine in addition to oral or intravenous nimodipine. Control groups consisted of 25 SAH patients with proven vasospasm and 20 SAH patients without. These patients received nimodipine therapy alone. Cranial computed tomography (CCT) before and after treatment was analyzed for CVS-related infarcts. A modified National Institutes...

Journal of Photochemistry and Photobiology B: Biology, 2015

Fluorescent agents, e.g. 5-aminolevulinic acid (5-ALA), fluorescein and indocyanine green (ICG) a... more Fluorescent agents, e.g. 5-aminolevulinic acid (5-ALA), fluorescein and indocyanine green (ICG) are in common use in neurosurgery for tumor resection and neurovascular surgery. Protoporphyrine IX (PPIX) as major metabolite of 5-ALA is a strong fluorescent substance accumulated within malignant glioma tissue and a very sensitive and specific tool for visualizing high grade glioma tissue during surgery. Furthermore, 5-ALA or rather PPIX also offers an intratumoral therapeutic option stimulated by laser light in specific wavelength. Fluorescein was demonstrated to show similar fluorescent reactions in neurosurgery, but is controversial in its use, especially in high grade tumor surgery. Intraoperative angiography during resection of arterio-venous malformations, extracranial-intracranial-bypass or aneurysm surgery is supported by ICG fluorescence. Generally ICG will provide beneficial information for both, exposure of the pathology and illustration of healthy structures. This manuscript shows an overview of the literature focussing fluorescence in neurosurgery.

World Neurosurgery, 2015

Myopericytomas are benign vascular tumors composed of perivascular myoid cells that usually arise... more Myopericytomas are benign vascular tumors composed of perivascular myoid cells that usually arise in superficial soft tissues of the extremities. We here report on 5 cases of myopericytoma, malignant myopericytoma, and glomangiopericytoma arising from subcutaneous, paraspinal, orbital, and sellar regions that secondarily involved the nervous system. Patients experienced orbital swelling, progressing neuropathic pain, dermatoma specific pain, and oculomotor paresis. Mean age at diagnosis was 56.8 years (range, 38-74 years). After a mean follow-up of 38 months, no recurrence was detected. All tumors were unencapsulated but relatively well-circumscribed lesions, showing typical histologic and immunohistochemical features of soft-tissue myopericytoma, including one malignant case. We conclude that myopericytoma may affect the nervous system and for prognostic and therapeutic reasons, needs to be differentiated from other vascular tumors.

Neurosurgery, 2008

A number of publications suggest that there are seasonal influences on the incidence of subarachn... more A number of publications suggest that there are seasonal influences on the incidence of subarachnoid hemorrhage (SAH). Most series agree on a peak incidence during springtime. Meteorological influences have been assumed to be obvious explanations for seasonal variations. Furthermore, the perceived clustering of the incidence of subarachnoid hemorrhage is also intuitively related to meteorological influences. The present study was initiated to determine whether specific meteorological conditions are related to the occurrence of SAH in the mild climatic zone of North Rhine Westphalia. We retrospectively examined 183 patients (107 women and 76 men) treated at our department between January 2003 and June 2005 for SAH that had occurred within the Düsseldorf metropolitan area. We correlated the date of SAH (Day 0) and of the week preceding the incident (Days -1, -3, -5, and -7) with the meteorological key parameters from Düsseldorf International Airport. Parameters analyzed were mean dail...

Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia, 2014

During treatment of large vestibular schwannomas, incomplete resection (IR) followed by Gamma Kni... more During treatment of large vestibular schwannomas, incomplete resection (IR) followed by Gamma Knife surgery (GKS; Elekta AB, Stockholm, Sweden) possibly offers tumor growth control and good clinical outcome, and is being discussed as an alternative to complete tumor removal with its inherent risks, especially for facial nerve function. However, available data for this concept are limited due to the small number of published studies. To analyze the effects of combined therapy in a larger cohort, we reviewed the currently available data. Six studies comprising 159 patients with a tumor diameter of at least 2 cm were included (median volume 19.95 cm(3) in four studies, n=137). GKS was performed on average 6 months postoperatively with a mean marginal dose of 11.88 Gy (mean target volume 4.42 cm(3), mean diameter 18.45 mm). Preoperatively facial nerve function was serviceable (House and Brackmann Grades I+II) in 158 of 159 patients (99.4%) and in 125 of 151 patients (82.8%, 95% confiden...

Central European neurosurgery, 2011

Photonic Therapeutics and Diagnostics, 2005

Oral application of 20 mg/kg bw of 5-aminolevulinic acid results in a highly specific accumulatio... more Oral application of 20 mg/kg bw of 5-aminolevulinic acid results in a highly specific accumulation of fluorescent and phototoxic Protoporphyrin IX in malignant glioma tissue. Surgical removal with fluorescence guidance is studied in a phase III clinical trial, adjuvant Photodynamic Therapy (PDT) to the surgical cavity is in phase II and for interstitial PDT of recurrent gliomas, a phase I/II

Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 2006

The aim of this study was to explore the differential diagnostic value of PET using the amino aci... more The aim of this study was to explore the differential diagnostic value of PET using the amino acid O-(2-(18)F-fluoroethyl)-L-tyrosine ((18)F-FET) in patients with newly diagnosed solitary intracerebral lesions showing ring enhancement on contrast-enhanced MRI. (18)F-FET PET analyses were performed on 14 consecutive patients with intracerebral ring-enhancing lesions. Eleven of the patients were additionally studied with (18)F-FDG PET. In all patients, the main differential diagnosis after MRI was a malignant lesion, in particular glioblastoma multiforme, versus a benign lesion, in particular brain abscess. A malignant tumor was suspected for lesions showing increased (18)F-FET uptake on PET images with a mean lesion-to-brain ratio of at least 1.6 ((18)F-FET PET positive). A nonneoplastic lesion was suspected in cases of minimal or absent (18)F-FET uptake, with a mean lesion-to-brain ratio of less than 1.6 ((18)F-FET PET negative). Histologic diagnosis was obtained by serial biopsies ...

Acta neurochirurgica, 2002

Photodynamic therapy (PDT) has been under discussion as additional treatment option for malignant... more Photodynamic therapy (PDT) has been under discussion as additional treatment option for malignant gliomas. However, damage not only to tumour tissue but also to normal brain has been demonstrated. The mechanisms of this unwanted side effect have not yet been clearly identified. Spreading of photosensitiser with oedema after disruption of the blood-brain-barrier and potential sensitisation of normal tissue has been found previously. The present study investigates the time- and dose-dependency of normal tissue damage to photodynamic therapy using Photofrin II after disruption of the blood-brain-barrier. Male wistar rats anaesthetised with chloral hydrate were subjected to focal, cerebral cold lesions. Simultaneously, Photofrin II (PFII) was injected (2,5 or 5 mg/kg b.w.). Laser irradiation (630 nm) was performed after 4 h, 12 h and 24 h with varying light doses. Control groups were subjected to focal cold lesion alone, cold lesion with laser irradiation, PFII followed by laser irradia...

Photodynamic Therapy: Back to the Future, 2009

Journal of Surgical Education, 2014

To establish and evaluate a new approach to teach medical students how to assess brain death in p... more To establish and evaluate a new approach to teach medical students how to assess brain death in patients. A total of 120 fourth-year medical students at Münster Medical School (Germany) participated in a 1-hour lecture on how to assess brain death in patients. After this lecture, students were assigned to 2 groups. One group attended an additional practical course on the evaluation of brain death and received training using a new high-fidelity simulation device. The other group did not participate in any additional training session. All students completed a questionnaire before the lecture and a second questionnaire at the conclusion of the study. For the group undergoing the additional training, the second questionnaire was completed after the additional training session. The additional practical training session significantly improved the students' performance in assessing brain death and promoted the self-assessment and motivation of the medical students. The establishment of a new practical teaching concept led to significant improvements in medical students' assessments of brain death in a practical session. These improvements in medical education could have significant implications for the clinical assessment of patients in the future.

Haemostasis in Spine Surgery, 2005

There are various electrical, mechanical and chemical methods used to achieve haemostasis in spin... more There are various electrical, mechanical and chemical methods used to achieve haemostasis in spine surgery. Chemical haemostatic agents are often preferable to bipolar cautery in intraspinal procedures, because these products control bleeding without occluding the vessel lumen and cause no thermal injuries to adjacent structures. A topical haemostat is the often the technique of choice to control bleeding from bone

Journal of neurosurgery, Jan 24, 2017

OBJECTIVE Fluorescence guidance with 5-aminolevulinic acid (5-ALA) helps improve resections of ma... more OBJECTIVE Fluorescence guidance with 5-aminolevulinic acid (5-ALA) helps improve resections of malignant gliomas. However, one limitation is the low intensity of blue light for background illumination. Fluorescein has recently been reintroduced into neurosurgery, and novel microscope systems are available for visualizing this fluorochrome, which highlights all perfused tissues but has limited selectivity for tumor detection. Here, the authors investigate a combination of both fluorochromes: 5-ALA for distinguishing tumor and fluorescein for providing tissue fluorescence of adjacent brain tissue. METHODS The authors evaluated 6 patients who harbored cerebral lesions suggestive of high-grade glioma. Patients received 5-ALA (20 mg/kg) orally 4 hours before induction of anesthesia. Low-dose fluorescein (3 mg/kg intravenous) was injected immediately after anesthesia induction. Pentero microscopes (equipped either with Yellow 560 or Blue 400 filters) were used to visualize fluorescence. T...

Objective: The purpose of this study was to determine the relationship of [18F]fluoroethyl-L-tyro... more Objective: The purpose of this study was to determine the relationship of [18F]fluoroethyl-L-tyrosine (FET) uptake in gliomas using PET and intraoperative 5-aminolevulinic acid (5-ALA) fluorescence using neuronavigated biopsies during resection as a reference. FET PET provides improved imaging[for full text, please go to the a.m. URL]

Forum, 2013

ZusammenfassungHintergrundDie aktuelle Literatur legt nahe, dass die primäre und möglichst radika... more ZusammenfassungHintergrundDie aktuelle Literatur legt nahe, dass die primäre und möglichst radikale Resektion von Gliomen die Prognose der Patienten verbessert. Entscheidend ist, dass dabei keine wesentlichen neurologischen Defizite entstehen.ErgebnisseIn diesem Zusammenhang konnten innerhalb der letzten Jahre Techniken zur prä- sowie intraoperativen Erkennung von Tumorgewebe und Funktionen entwickelt bzw. verbessert werden, z. B. die Positronenemissionstomographie (PET) mit Aminosäuren, die funktionelle MRT, die navigierte Hirnstimulation, Fluoreszenzmethoden und der intraoperative Einsatz der MRT. Der vorliegende Beitrag gibt einen Überblick über aktuelle Entwicklungen in der Chirurgie hirneigener Tumoren.AbstractBackgroundThe current literature strongly supports radical resection of gliomas as the first line therapy to improve the prognosis of patients. However, it is important that no significant neurological deficits result.ResultsAccordingly, a number of pre- and intra-operative techniques for the identification of functionally intact brain and infiltrating tumor tissue have been developed, e.g., amino acid positron emission tomography, functional MRI, fluorescence techniques, navigated brain stimulation, and the intra-operative MRI. This review summarizes recent developments in the field of neurosurgery for the management of gliomas.

PloS one, 2016

Pituitary adenomas (PA), especially invasive ones, are often not completely resectable. Usage of ... more Pituitary adenomas (PA), especially invasive ones, are often not completely resectable. Usage of 5-aminolevulinic acid (5-ALA) for fluorescence guided surgery could improve the rate of total resection and, additionally, open the doors for photodynamic therapy (PDT) in case of unresectable or partially resected PAs. The aim of this study was to investigate the uptake of 5-ALA and the effect of 5-ALA based PDT in cell lines. GH3 and AtT-20 cell lines were incubated with different concentrations of 5-ALA, protoporphyrin IX (PPIX) fluorescence was measured by flow cytometry and fluorescencespectrometry. WST-1 assays were performed to determine the surviving fraction of cells after PDT. PPIX fluorescence intensities and PDT effect of the pituitary adenoma cells were compared to U373MG, a well-known glioblastoma cell line. Both cell lines showed a 5-ALA dependent intracellular PPIX fluorescence. Significant differences after 24hrs of incubation were observed in AtT-20 cells in comparison ...

RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren, 2007

Journal of Neuro-Oncology, 2007

Aminolevulinic acid (ALA)-mediated photodynamic therapy (PDT) may represent a treatment option fo... more Aminolevulinic acid (ALA)-mediated photodynamic therapy (PDT) may represent a treatment option for malignant brain tumors. We used a three-dimensional cell culture system, the C6 glioma spheroid model, to study acute effects of PDT and how they might be influenced by treatment conditions. Spheroids were incubated for 4 h in 100 microg/ml ALA in 5% CO(2) in room air or 95% O(2) with subsequent irradiation using a diode laser (lambda = 635 nm, 40 mW/cm(2), total fluence 25 J/cm(2)). Control groups were "laser only", "ALA only", and "no drug no light". Annexin V-FITC, a marker used for detection of apoptosis, propidium iodide (PI), a marker for necrotic cells and H 33342, a chromatin stain, were used for morphological characterization of PDT effects by confocal laser scanning and fluorescence microscopy. Hematoxylin-eosin staining and TdT-FragEL (TUNEL) assay were used on cryosections. Growth kinetics were followed for 8 days after PDT. PDT after incubation in 5% CO(2) provided incomplete cell death and growth delay in spheroids of >350 microm diameter. However, complete cell death and growth arrest occurred in smaller spheroids (<350 microm). Incubation in 95% O(2) with subsequent PDT resulted in complete cell death and growth arrest regardless of spheroid size. In incompletely damaged spheroids viable cells were restricted to spheroid centers. The rate of cell death in all control groups was negligible. Cell death was accompanied by annexin/PI costaining, but there was also evidence for annexin V-FITC staining without PI uptake. PDT of experimental glioma results in rapid and significant cell death that could be verified as acute necrosis immediately after irradiation. This effect depended on O(2) concentration and spheroid size.

Journal of Neurosurgery Pediatrics

Pineal cysts are benign and often asymptomatic intracranial entities. Occasionally they can lead ... more Pineal cysts are benign and often asymptomatic intracranial entities. Occasionally they can lead to neurological symptoms through growth or due to intracystic hemorrhage. The purpose of the current report is to describe their clinical characteristics and treatment options. In the current study, the authors illustrate the course of disease in 3 patients who developed neurological symptoms due to hemorrhage into a pineal cyst. Two of their patients had additional cerebral disease, and regular MR imaging examinations were conducted. This circumstance allowed documentation of growth and intracystic hemorrhage. After the occurrence of new neurological symptoms with severe headache, MR images showed a fluid-fluid interface due to intracystic hemorrhage. The third patient presented with acute triventricular hydrocephalus and papilledema due to aqueductal stenosis caused by intracystic hemorrhage. In all 3 cases, excision of the pineal cysts via an infratentorial/supracerebellar approach wa...

Brain tumor pathology, Jan 21, 2015

Telomerase reverse transcriptase (TERT) expression is a hallmark in tumorigenesis and upregulated... more Telomerase reverse transcriptase (TERT) expression is a hallmark in tumorigenesis and upregulated due to mutations and methylation of the human (h)TERT promoter. As mutations are rare but methylation is common in pituitary adenomas (PA), we determined promoter methylation and its clinical impact in 85 primary and 15 recurrent PA by methylation-specific PCR. 40 females (47 %) and 45 males (53 %) with a median age of 53 years harboring micro-, macro-, and giant adenomas in 12, 82, and 6 % were included (prolactinomas, corticotroph, somatotroph, gonadotroph, thyreotroph, plurihormonal, and null cell adenomas in 11, 18, 10, 29, 1, 10, and 21 %, respectively). In primary diagnosed tumors, methylation rate was 27 % and higher in males than in females (40 vs. 13 %, p = 0.001) after uni- and multivariate analyses. Methylation differed among PA subtypes (0-42 %, p = n.s.) and was not significantly correlated with tumor size, cavernous sinus invasion, or serum hormone levels. Ki67 labeling in...

Journal of neurosurgery, Jan 10, 2015

OBJECT Delayed ischemic neurological deficits (DINDs) and cerebral vasospasm (CVS) are responsibl... more OBJECT Delayed ischemic neurological deficits (DINDs) and cerebral vasospasm (CVS) are responsible fora poor outcome in patients with aneurysmal subarachnoid hemorrhage (SAH), most likely because of a decreased availability of nitric oxide (NO) in the cerebral microcirculation. In this study, the authors examined the effects of treatment with the NO donor molsidomine with regard to decreasing the incidence of spasm-related delayed brain infarctions and improving clinical outcome in patients with SAH. METHODS Seventy-four patients with spontaneous aneurysmal SAH were included in this post hoc analysis. Twenty-nine patients with SAH and proven CVS received molsidomine in addition to oral or intravenous nimodipine. Control groups consisted of 25 SAH patients with proven vasospasm and 20 SAH patients without. These patients received nimodipine therapy alone. Cranial computed tomography (CCT) before and after treatment was analyzed for CVS-related infarcts. A modified National Institutes...

Journal of Photochemistry and Photobiology B: Biology, 2015

Fluorescent agents, e.g. 5-aminolevulinic acid (5-ALA), fluorescein and indocyanine green (ICG) a... more Fluorescent agents, e.g. 5-aminolevulinic acid (5-ALA), fluorescein and indocyanine green (ICG) are in common use in neurosurgery for tumor resection and neurovascular surgery. Protoporphyrine IX (PPIX) as major metabolite of 5-ALA is a strong fluorescent substance accumulated within malignant glioma tissue and a very sensitive and specific tool for visualizing high grade glioma tissue during surgery. Furthermore, 5-ALA or rather PPIX also offers an intratumoral therapeutic option stimulated by laser light in specific wavelength. Fluorescein was demonstrated to show similar fluorescent reactions in neurosurgery, but is controversial in its use, especially in high grade tumor surgery. Intraoperative angiography during resection of arterio-venous malformations, extracranial-intracranial-bypass or aneurysm surgery is supported by ICG fluorescence. Generally ICG will provide beneficial information for both, exposure of the pathology and illustration of healthy structures. This manuscript shows an overview of the literature focussing fluorescence in neurosurgery.

World Neurosurgery, 2015

Myopericytomas are benign vascular tumors composed of perivascular myoid cells that usually arise... more Myopericytomas are benign vascular tumors composed of perivascular myoid cells that usually arise in superficial soft tissues of the extremities. We here report on 5 cases of myopericytoma, malignant myopericytoma, and glomangiopericytoma arising from subcutaneous, paraspinal, orbital, and sellar regions that secondarily involved the nervous system. Patients experienced orbital swelling, progressing neuropathic pain, dermatoma specific pain, and oculomotor paresis. Mean age at diagnosis was 56.8 years (range, 38-74 years). After a mean follow-up of 38 months, no recurrence was detected. All tumors were unencapsulated but relatively well-circumscribed lesions, showing typical histologic and immunohistochemical features of soft-tissue myopericytoma, including one malignant case. We conclude that myopericytoma may affect the nervous system and for prognostic and therapeutic reasons, needs to be differentiated from other vascular tumors.

Neurosurgery, 2008

A number of publications suggest that there are seasonal influences on the incidence of subarachn... more A number of publications suggest that there are seasonal influences on the incidence of subarachnoid hemorrhage (SAH). Most series agree on a peak incidence during springtime. Meteorological influences have been assumed to be obvious explanations for seasonal variations. Furthermore, the perceived clustering of the incidence of subarachnoid hemorrhage is also intuitively related to meteorological influences. The present study was initiated to determine whether specific meteorological conditions are related to the occurrence of SAH in the mild climatic zone of North Rhine Westphalia. We retrospectively examined 183 patients (107 women and 76 men) treated at our department between January 2003 and June 2005 for SAH that had occurred within the Düsseldorf metropolitan area. We correlated the date of SAH (Day 0) and of the week preceding the incident (Days -1, -3, -5, and -7) with the meteorological key parameters from Düsseldorf International Airport. Parameters analyzed were mean dail...

Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia, 2014

During treatment of large vestibular schwannomas, incomplete resection (IR) followed by Gamma Kni... more During treatment of large vestibular schwannomas, incomplete resection (IR) followed by Gamma Knife surgery (GKS; Elekta AB, Stockholm, Sweden) possibly offers tumor growth control and good clinical outcome, and is being discussed as an alternative to complete tumor removal with its inherent risks, especially for facial nerve function. However, available data for this concept are limited due to the small number of published studies. To analyze the effects of combined therapy in a larger cohort, we reviewed the currently available data. Six studies comprising 159 patients with a tumor diameter of at least 2 cm were included (median volume 19.95 cm(3) in four studies, n=137). GKS was performed on average 6 months postoperatively with a mean marginal dose of 11.88 Gy (mean target volume 4.42 cm(3), mean diameter 18.45 mm). Preoperatively facial nerve function was serviceable (House and Brackmann Grades I+II) in 158 of 159 patients (99.4%) and in 125 of 151 patients (82.8%, 95% confiden...

Central European neurosurgery, 2011

Photonic Therapeutics and Diagnostics, 2005

Oral application of 20 mg/kg bw of 5-aminolevulinic acid results in a highly specific accumulatio... more Oral application of 20 mg/kg bw of 5-aminolevulinic acid results in a highly specific accumulation of fluorescent and phototoxic Protoporphyrin IX in malignant glioma tissue. Surgical removal with fluorescence guidance is studied in a phase III clinical trial, adjuvant Photodynamic Therapy (PDT) to the surgical cavity is in phase II and for interstitial PDT of recurrent gliomas, a phase I/II

Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 2006

The aim of this study was to explore the differential diagnostic value of PET using the amino aci... more The aim of this study was to explore the differential diagnostic value of PET using the amino acid O-(2-(18)F-fluoroethyl)-L-tyrosine ((18)F-FET) in patients with newly diagnosed solitary intracerebral lesions showing ring enhancement on contrast-enhanced MRI. (18)F-FET PET analyses were performed on 14 consecutive patients with intracerebral ring-enhancing lesions. Eleven of the patients were additionally studied with (18)F-FDG PET. In all patients, the main differential diagnosis after MRI was a malignant lesion, in particular glioblastoma multiforme, versus a benign lesion, in particular brain abscess. A malignant tumor was suspected for lesions showing increased (18)F-FET uptake on PET images with a mean lesion-to-brain ratio of at least 1.6 ((18)F-FET PET positive). A nonneoplastic lesion was suspected in cases of minimal or absent (18)F-FET uptake, with a mean lesion-to-brain ratio of less than 1.6 ((18)F-FET PET negative). Histologic diagnosis was obtained by serial biopsies ...

Acta neurochirurgica, 2002

Photodynamic therapy (PDT) has been under discussion as additional treatment option for malignant... more Photodynamic therapy (PDT) has been under discussion as additional treatment option for malignant gliomas. However, damage not only to tumour tissue but also to normal brain has been demonstrated. The mechanisms of this unwanted side effect have not yet been clearly identified. Spreading of photosensitiser with oedema after disruption of the blood-brain-barrier and potential sensitisation of normal tissue has been found previously. The present study investigates the time- and dose-dependency of normal tissue damage to photodynamic therapy using Photofrin II after disruption of the blood-brain-barrier. Male wistar rats anaesthetised with chloral hydrate were subjected to focal, cerebral cold lesions. Simultaneously, Photofrin II (PFII) was injected (2,5 or 5 mg/kg b.w.). Laser irradiation (630 nm) was performed after 4 h, 12 h and 24 h with varying light doses. Control groups were subjected to focal cold lesion alone, cold lesion with laser irradiation, PFII followed by laser irradia...

Photodynamic Therapy: Back to the Future, 2009

Journal of Surgical Education, 2014

To establish and evaluate a new approach to teach medical students how to assess brain death in p... more To establish and evaluate a new approach to teach medical students how to assess brain death in patients. A total of 120 fourth-year medical students at Münster Medical School (Germany) participated in a 1-hour lecture on how to assess brain death in patients. After this lecture, students were assigned to 2 groups. One group attended an additional practical course on the evaluation of brain death and received training using a new high-fidelity simulation device. The other group did not participate in any additional training session. All students completed a questionnaire before the lecture and a second questionnaire at the conclusion of the study. For the group undergoing the additional training, the second questionnaire was completed after the additional training session. The additional practical training session significantly improved the students' performance in assessing brain death and promoted the self-assessment and motivation of the medical students. The establishment of a new practical teaching concept led to significant improvements in medical students' assessments of brain death in a practical session. These improvements in medical education could have significant implications for the clinical assessment of patients in the future.

Haemostasis in Spine Surgery, 2005

There are various electrical, mechanical and chemical methods used to achieve haemostasis in spin... more There are various electrical, mechanical and chemical methods used to achieve haemostasis in spine surgery. Chemical haemostatic agents are often preferable to bipolar cautery in intraspinal procedures, because these products control bleeding without occluding the vessel lumen and cause no thermal injuries to adjacent structures. A topical haemostat is the often the technique of choice to control bleeding from bone