C. Nimsky

Diffusion tensor imaging and white matter tractography in patients with brainstem lesions

SummaryBackground. Diffusion tensor imaging (DTI) and white matter tractography (WMT) are promising techniques for estimating the course, extent, and connectivity patterns of the white matter (WM) structures in the human brain. In this study, we investigated the ability of DTI and WMT to visualize white matter tract involvement for the preoperative surgical planning and postoperative assessment of brainstem lesions.Methods. Preoperative and postoperative DTI data (echo-planar, 1.5T) were retrospectively analyzed in 10 patients with brainstem lesions (3 diffuse, 7 focal). WMT applying a tensor deflection algorithm was used to reconstruct WM tracts adjacent to the lesions. Reconstructed tracts included corticospinal tracts and medial lemnisci. The clinical and imaging follow-up data were also compared and analyzed.Findings. WMT revealed a series of tract alteration patterns including deviation, deformation, infiltration, and apparent tract interruption. WMT reconstructions showed that the major WM tracts were preserved during surgery and improved in position and appearance postoperatively. These findings correlated with the improvement or preservation of neurological function as determined by clinical assessment.Conclusions. Compared with the information provided by conventional MR imaging, DTI and WMT provided superior quantification and visualization of lesion involvement in eloquent fibre tracts of the brainstem. Moreover, DTI and WMT were found to be beneficial for white matter recognition in the neurosurgical planning and postoperative assessment of brainstem lesions.

Magnetic source imaging supports clinical decision making in glioma patients

OBJECTIVE This study addresses the potential utility of preoperative functional imaging with magnetoencephalography (MEG) for the selection of glioma patients who are likely to benefit from resective surgical treatment regarding postoperative morbidity. METHODS One hundred and nineteen patients with gliomas adjacent to sensorimotor, visual and speech related brain areas were investigated preoperatively with a MAGNES II biomagnetometer. In each patient the pre-surgical evaluation was focussed on the visual, sensorimotor cortex and/or of the speech related brain areas. A grading system was then used according to the distance of the MEG activation sources to the nearest tumour border to determine the further treatment. The therapeutic options consisted in conservative treatment, stereotactic biopsy and/or a radiation and chemotherapy, substantial cytoreduction and the gross total removal of the lesion. RESULTS From 119 investigated patients, 55 patients (46.2%) were not considered for surgery due to tumour invasion to functional cortex. Sixty four patients (53.8%) were chosen for resective surgery. In the surgical group only four patients (6.2%) suffered from neurological deterioration. CONCLUSIONS Magnetic source imaging (MSI) proved to be a valuable help in the clinical decision making process of lesions adjacent to functional important brain areas. The relative high number of patients in whom MSI warns of the postoperative crippling sequelae may lead to a better selection of patients who benefit from resective surgery. This method may help to find the patients for whom conservative treatment seems to be more favourable concerning quality of life in the surviving time.

Intraoperative imaging with open magnetic resonance imaging and neuronavigation

Abstract The Erlangen-concept of image-guided-surgery is based on the installation of an open magnetic resonance (MR) scanner (Magnetom Open, 0.2 T, Siemens AG) in a twin operating room in combination with two neuronavigation systems (Stealth NeuroStation, Sofamor Danek, MKM Zeiss). Since March 1996 this method has been used for a total of 402 patients, among them 44 children. In 214 patients, mainly with gliomas or pituitary adenomas or who needed surgery for epilepsy, we performed intraoperative MR imaging to monitor the extent of resection, allowing a second look for possible tumor remnants and also compensating for brain shift by an intraoperative update of neuronavigation. Functional neuronavigation, i.e. the combination of anatomical neuronavigation with functional imaging [e.g. magnetoencephalography (MEG) and functional magnetic resonance imaging (fMRI)] was used in patients with lesions in brain areas such as the motor and speech areas. For MEG we used a MAGNES II biomagnetometer (Biomagnetic Technologies, San Diego, Calif.) and for fMRI a 1.5 T Siemens Symphony MR scanner. So far we have treated 89 patients with functional neuronavigation. Our preliminary experience indicates that intraoperative MR imaging, especially in combination with functional neuronavigation, allows more radical resections with lower morbidity.

Open surgery of giant paraclinoid aneurysms improved by intraoperative angiography and endovascular retrograde suction decompression

SummaryIn three consecutive cases of giant left sided paraclinoid aneurysms we employed an endovascular retrograde suction decompression technique in combination with intra-operative angiography. A double-lumen balloon catheter was placed in the left internal carotid artery by the transfemoral route. After balloon inflation and placement of a temporary clip distal to the aneurysm blood was aspirated and the aneurysm collapsed. Thus further dissection of the aneurysm could easily be achieved and clips could be placed. Afterwards real-time digital subtraction angiography was performed. Intra-operative angiography led to clip repositioning in all cases either due to a clip induced stenosis of the parent vessel, or because of incomplete aneurysm obliteration. Afterwards successful clipping could be confirmed in all cases. Outcome was excellent in one case, good in the other. The third case, extremely complicated by an accompanying craniopharyngioma, showed a satisfactory outcome, but presented new neurological deficits.

Treatment of intraventricular hemorrhage and hydrocephalus

Most cases of intraventricular hemorrhage (IVH) occur secondary to spontaneous intracerebral or subarachnoid hemorrhage. The main concern is development of hydrocephalus, which is related to a poor prognosis. Over the last years, several treatment options for IVH have been introduced, but prospective data regarding the efficacy of those therapies (external ventricular drainage, intraventricular fibrinolysis, lumbar drainage, endoscopic hematoma evacuation) do not yet exist. This review focuses on combined therapy using an external ventricular drain and intraventricular fibrinolysis with r-TPA for IVH-associated initial occlusive hydrocephalus. Moreover, a continuing treatment strategy for persistent malresorptive communicating hydrocephalus using lumbar drainage is described.ZusammenfassungDie intraventrikuläre Blutung (IVB) – meist sekundär im Anschluss an eine spontane intrazerebrale Blutung oder Subarachnoidalblutung – birgt als Hauptgefahr die Entwicklung eines Hydrozephalus, der mit einer schlechten Prognose assoziiert ist. In den letzten Jahren sind verschiedene Therapieoptionen zur Akutbehandlung der IVB beschrieben worden, jedoch basiert bislang kein Therapieansatz auf prospektiven Studien. Diese Übersichtsarbeit stellt die einzelnen Therapiemöglichkeiten der IVB vor, einschließlich der externen Ventrikeldrainage (EVD), der intraventrikulären Fibrinolyse, der Lumbaldrainage und der neuroendoskopischen Verfahren. Schwerpunkt wird die Darstellung der kombinierten Behandlung des – sich aufgrund intraventrikulärer Blutanteile entwickelnden – initialen okklusiven Hydrozephalus mittels einer EVD und der intraventrikulären Fibrinolyse mit rt-PA sein sowie die Erläuterung der weiterführenden Therapie des malresorptiven, kommunizierenden Hydrozephalus mittels Lumbaldrainage.SummaryMost cases of intraventricular hemorrhage (IVH) occur secondary to spontaneous intracerebral or subarachnoid hemorrhage. The main concern is development of hydrocephalus, which is related to a poor prognosis. Over the last years, several treatment options for IVH have been introduced, but prospective data regarding the efficacy of those therapies (external ventricular drainage, intraventricular fibrinolysis, lumbar drainage, endoscopic hematoma evacuation) do not yet exist. This review focuses on combined therapy using an external ventricular drain and intraventricular fibrinolysis with r-TPA for IVH-associated initial occlusive hydrocephalus. Moreover, a continuative treatment strategy for persistent malresorptive communicating hydrocephalus using lumbar drainage is described.

Der Nutzen von Magnetoenzephalographie und funktioneller Neuronavigation bei der Planung und Operation von Hirntumoren

ZusammenfassungDie Magnetoenzephalographie (MEG) wird in den nervenärztlichen Fächern vor allem für Grundlagenforschung, für die Epilepsiediagnostik und für die Lokalisation funktioneller Hirnareale benutzt. Die funktionelle Lokalisationsdiagnostik hat sich zu einer wichtigen klinischen Anwendung des MEG entwickelt, die dem Neurologen und dem Neurochirurgen Entscheidungshilfen bei der Indikationsstellung, Planung und Durchführung einer Operation geben kann. Die Integration dieser Daten in moderne Operationsverfahren wie die Neuronavigation kann dazu beitragen, dass postoperative neurologische Defizite vermieden werden können. Insbesondere bei niedergradigen Gliomen ist die Entscheidung zur Operation besonders verantwortungsvoll, da eine zeitliche Verlängerung bis zum Auftreten eines Rezidivs nur bei makroskopisch kompletter Resektion erreicht werden kann. Eine neurologische Verschlechterung bedeutet für diese Patienten ein hohe Einbuße an Lebensqualität. Der folgende Beitrag berichtet über unsere Erfahrungen beim Einsatz des MEG, kombiniert mit Neuronavigation bei der Behandlung von Hirntumoren in der Nähe funktionell wichtiger Hirnareale.SummaryThe role of magnetoencephalography (MEG) in neurology has been established for basic research, epilepsy, and functional brain mapping. The presurgical localization of functionally important brain areas has evolved as an important application of MEG. Both neurologists and neurosurgeons can use this method for decision-making and planning of nonsurgical or surgical treatment in brain tumors. The integration of functional brain mapping data into neuronavigation systems may help to minimize postoperative morbidity. This is especially important in low-grade gliomas, in which a potential benefit of surgery is only achieved when the tumor has been resected completely, whereas neurological deterioration means a substantial loss of quality of life during the survival time. This report addresses the utility of MEG combined with neuronavigation in the treatment of brain tumors adjacent to eloquent brain areas.

Behandlung von intraventrikulären Blutungen und Hydrozephalus

Most cases of intraventricular hemorrhage (IVH) occur secondary to spontaneous intracerebral or subarachnoid hemorrhage. The main concern is development of hydrocephalus, which is related to a poor prognosis. Over the last years, several treatment options for IVH have been introduced, but prospective data regarding the efficacy of those therapies (external ventricular drainage, intraventricular fibrinolysis, lumbar drainage, endoscopic hematoma evacuation) do not yet exist. This review focuses on combined therapy using an external ventricular drain and intraventricular fibrinolysis with r-TPA for IVH-associated initial occlusive hydrocephalus. Moreover, a continuing treatment strategy for persistent malresorptive communicating hydrocephalus using lumbar drainage is described.ZusammenfassungDie intraventrikuläre Blutung (IVB) – meist sekundär im Anschluss an eine spontane intrazerebrale Blutung oder Subarachnoidalblutung – birgt als Hauptgefahr die Entwicklung eines Hydrozephalus, der mit einer schlechten Prognose assoziiert ist. In den letzten Jahren sind verschiedene Therapieoptionen zur Akutbehandlung der IVB beschrieben worden, jedoch basiert bislang kein Therapieansatz auf prospektiven Studien. Diese Übersichtsarbeit stellt die einzelnen Therapiemöglichkeiten der IVB vor, einschließlich der externen Ventrikeldrainage (EVD), der intraventrikulären Fibrinolyse, der Lumbaldrainage und der neuroendoskopischen Verfahren. Schwerpunkt wird die Darstellung der kombinierten Behandlung des – sich aufgrund intraventrikulärer Blutanteile entwickelnden – initialen okklusiven Hydrozephalus mittels einer EVD und der intraventrikulären Fibrinolyse mit rt-PA sein sowie die Erläuterung der weiterführenden Therapie des malresorptiven, kommunizierenden Hydrozephalus mittels Lumbaldrainage.SummaryMost cases of intraventricular hemorrhage (IVH) occur secondary to spontaneous intracerebral or subarachnoid hemorrhage. The main concern is development of hydrocephalus, which is related to a poor prognosis. Over the last years, several treatment options for IVH have been introduced, but prospective data regarding the efficacy of those therapies (external ventricular drainage, intraventricular fibrinolysis, lumbar drainage, endoscopic hematoma evacuation) do not yet exist. This review focuses on combined therapy using an external ventricular drain and intraventricular fibrinolysis with r-TPA for IVH-associated initial occlusive hydrocephalus. Moreover, a continuative treatment strategy for persistent malresorptive communicating hydrocephalus using lumbar drainage is described.

Intraoperative Magnetresonanztomographie Erfahrungen beim Einsatz in der Neurochirurgie

ZusammenfassungBei insgesamt 243 Patienten wurde die Magnetresonanztomographie (MR) zur intraoperativen Bildgebung eingesetzt, wobei ein offener 0,2 Tesla MR-Scanner verwendet wurde. Ziel der vorliegenden Arbeit ist es, die technische Machbarkeit, klinische Anwendung und die inzwischen entwickelten Indikationen darzustellen.Es wurden keine negativen Folgen, die durch die intraoperative Bildgebung verursacht wurden, beobachtet. Das Ausmaß der Tumorresektion konnte in der überwiegenden Mehrzahl aller Fälle dargestellt werden. Wesentliche Indikationen für die intraoperative MR sind die Resektionskontrolle bei Gliomen, bei Ventrikel- und Hypophysentumoren, sowie die intraoperative Bildgebung im Rahmen der Epilepsiechirurgie.Die intraoperative MR-Bildgebung erlaubt, insbesondere bei gleichzeitiger Anwendung der funktionellen Neuronavigation, radikalere Resektionen bei geringerer Morbidität. Es besteht die Möglichkeit des “second look”, um eine inkomplette Resektion während des gleichen Eingriffes zu vervollständigen. Auch kann der sog. “brain shift”, d. h. die Verlagerung des Gehirns, die während der Operation zu einer zunehmenden Ungenauigkeit der Neuronavigation führt, ausgeglichen werden.SummaryIntraoperative magnetic resonance imaging using a 0.2 Tesla, open-configured scanner was applied in a total of 243 patients. The aim of this study was to evaluate the feasibility, clinical application, and indications of this method. No adverse effects of the intraoperative imaging could be observed. The extent of tumor resection could be evaluated in the majority of cases. Resection control in glioma, ventricular tumor, pituitary tumor, and epilepsy surgery were the main indications for the intraoperative application.Especially when combined with functional neuronavigation, intraoperative magnetic resonance imaging allowed more radical resectioning with lower morbidity. Second looks to complete tumor removal during the same surgical procedure were possible to determine tumor remnants. Brain shift, which reduces the accuracy of neuronavigational systems, could be compensated for by intraoperative updates.

Behandlung von intraventrikulären Blutungen und Hydrozephalus@@@Treatment of intraventricular hemorrhage and hydrocephalus

Most cases of intraventricular hemorrhage (IVH) occur secondary to spontaneous intracerebral or subarachnoid hemorrhage. The main concern is development of hydrocephalus, which is related to a poor prognosis. Over the last years, several treatment options for IVH have been introduced, but prospective data regarding the efficacy of those therapies (external ventricular drainage, intraventricular fibrinolysis, lumbar drainage, endoscopic hematoma evacuation) do not yet exist. This review focuses on combined therapy using an external ventricular drain and intraventricular fibrinolysis with r-TPA for IVH-associated initial occlusive hydrocephalus. Moreover, a continuing treatment strategy for persistent malresorptive communicating hydrocephalus using lumbar drainage is described.ZusammenfassungDie intraventrikuläre Blutung (IVB) – meist sekundär im Anschluss an eine spontane intrazerebrale Blutung oder Subarachnoidalblutung – birgt als Hauptgefahr die Entwicklung eines Hydrozephalus, der mit einer schlechten Prognose assoziiert ist. In den letzten Jahren sind verschiedene Therapieoptionen zur Akutbehandlung der IVB beschrieben worden, jedoch basiert bislang kein Therapieansatz auf prospektiven Studien. Diese Übersichtsarbeit stellt die einzelnen Therapiemöglichkeiten der IVB vor, einschließlich der externen Ventrikeldrainage (EVD), der intraventrikulären Fibrinolyse, der Lumbaldrainage und der neuroendoskopischen Verfahren. Schwerpunkt wird die Darstellung der kombinierten Behandlung des – sich aufgrund intraventrikulärer Blutanteile entwickelnden – initialen okklusiven Hydrozephalus mittels einer EVD und der intraventrikulären Fibrinolyse mit rt-PA sein sowie die Erläuterung der weiterführenden Therapie des malresorptiven, kommunizierenden Hydrozephalus mittels Lumbaldrainage.SummaryMost cases of intraventricular hemorrhage (IVH) occur secondary to spontaneous intracerebral or subarachnoid hemorrhage. The main concern is development of hydrocephalus, which is related to a poor prognosis. Over the last years, several treatment options for IVH have been introduced, but prospective data regarding the efficacy of those therapies (external ventricular drainage, intraventricular fibrinolysis, lumbar drainage, endoscopic hematoma evacuation) do not yet exist. This review focuses on combined therapy using an external ventricular drain and intraventricular fibrinolysis with r-TPA for IVH-associated initial occlusive hydrocephalus. Moreover, a continuative treatment strategy for persistent malresorptive communicating hydrocephalus using lumbar drainage is described.

Intraoperative Identifikation und Überwachung von Kerngebieten des Hirnstamms durch direkte elektrische Stimulation

Die zuverlassige intraoperative Identifizierung von Kerngebieten des Hirnstamms konnte bei intramedullaren Prozessen zu einer Erweiterung der operativen Moglichkeiten beitragen. Operationen bei raumfordernden Prozessen im Hirnstamm konnen durch die Konzentration von Bahnensystemen und Kerngebieten in ihrem Ausmas limitiert sein (Epstein 1988; Heffez 1990). Die guten funktionellen Ergebnisse bei cavernosen Hamangiomen des Hirnstamms zeigen, das trotz der Konzentration von Bahnen und Kerngebieten abgegrenzte Prozesse ohne zusatzliche Defizite entfernt werden konnen (Fahlbusch 1991; Weil 1990).