Effective long-term subthalamic stimulation in PARK8 positive Parkinson's disease.

Whether patients with genetically defined Parkinson's disease (PD) may be particularly eligible to benefit from deep brain stimulation of the nucleus subthalamicus (STN-DBS) is currently the subject of debate. We report on a patient with advanced PD due to R793M missense mutation in the LRRK2 gene successfully treated by STN-DBS. Disease onset was at age 42 with bradykinesia, rigidity and rest tremor. During the course of the disease he developed severe motor fluctuations, dyskinesias, postural instability with falls, but preserved levodopa responsiveness. At age 60 the patient was treated by bilateral DBS of the STN. At one year after surgery a 66% improvement of the UPDRS motor score in the off-medication state was determined. During the long-term follow-up there was sustained benefit with 56% improvement of motor score after 8 years. Our report adds evidence that patients with LRRK2 monogenetic Parkinsonism are well suited candidates for DBS treatment and may indicate a potential genetic predictor for positive long-term effect of STN-DBS treatment.

Effective thalamic deep brain stimulation for neuropathic tremor in a patient with severe demyelinating neuropathy.

Postural and action tremor in peripheral neuropathy is characteristic of Roussy-Levy syndrome. A patient with a severe demyelinating neuropathy and disabling neuropathic tremor successfully treated by deep brain stimulation (DBS) is reported. Disease onset was at age 63 years with sensory symptoms and slight action tremor. Within the following 9 years a severe, drug resistant, postural and action tremor developed rendering the patient unable to feed himself. At age 72 years the patient was treated by bilateral DBS of the ventral intermediate thalamic nucleus, with a useful 30% reduction in tremor. The clinical benefit of the stimulation remained stable over a 1 year postoperative observation period.

De novo erythropoietin receptor (EPO-R) expression in human neoplastic glial cells decreases with grade of malignancy but is favourably associated with patient survival.

The erythropoietin receptor (EPO-R) is mainly known as a regulator of erythropoiesis. However, recent studies revealed that the EPO-R is not exclusively expressed in haematopoietic tissues but also in various cancer cell types and normal tissue such as the central nervous system (CNS). EPO-R is up-regulated under hypoxia and is able to counteract the deleterious effects of hypoxia on tumour growth, metastasis and treatment resistance. Therefore, the EPO-EPO-R signalling pathway is considered as a possible target for tumour treatment. Here, we investigated brain tumour samples obtained from patients between 1993 and 2003 to study EPO-R expression in vivo. Tissue samples included 194 gliomas of different WHO grades, additionally 25 infiltration zone samples and 31 relapses of WHO grade IV glioblastomas as well as 23 normal CNS tissue specimens to address the in vivo situation. Immunohistochemistry of the tissue microarray samples revealed significantly higher levels of EPO-R expression in neoplastic glial cells compared with glial cells derived from normal brain. EPO-R expression showed a highly significant decrease from low- to high-grade gliomas. Age-stratified Kaplan-Meier analysis revealed longer survival for patients exhibiting high EPO-R status in high-grade gliomas. Our results show a grade-dependent EPO-R down-regulation and might contribute to the understanding of high-grade glioma resistance to radio- and chemotherapy as both were shown to be improved by a well functioning EPO-EPO-R pathway in previous studies. Further studies are needed to investigate to what extent the decreased mortality in age-stratified patient groups with high EPO-R levels reflects a direct beneficial role of EPO-R expression.

Fronto-laterally located supratentorial bronchogenic cyst: case report and review of the literature.

Bronchogenic cysts are rare findings within the central nervous system and even extremely seldom if they are located supratentorially. We report on a 25-year-old man who presented with a single generalized seizure without any accompanying neurological deficit 6 weeks prior to admission. MRI showed a smoothly limited, non-calcified cyst of a maximum of 55 mm in diameter. Large parts of the membrane were removed through a right anterior craniotomy, and a fenestration into the subarachnoidal space was performed. Histopathological examinations revealed a bronchogenic cyst. Previous reports of neurenteric cysts are reviewed. Therapeutic options, pathogenesis and categorization of this uncommon congenital entity are discussed.

Recurrence and increased proliferation rate of a solitary fibrous tumor in the central nervous system--case report and review of the literature.

Meningeal solitary fibrous tumors (SFTs) were at first estimated as rare benign tumors which can be cured by total resection. To date, only 37 patients with intracranial SFTs have been reported. Therefore, the natural history of this tumor entity needs more enlightenment. The authors report a case of a 77-year-old female in whom a SFT with infiltration of the transversal sinus was subtotally resected. After a short time, interval tumor recurrence was seen, 2 years and 6 months later second surgery was performed. Immunohistologically, in both specimens typical features for SFT with positivity for CD34, vimentin and BCL-2 and negative for epithelial membrane antigen was seen. No signs for malignancy occurred in the second resection. Notably the MIB-1 index increased from 1 to 5%. In conclusion, consequent long-time follow-up for SFTs are necessary, especially after incomplete tumor resection.

Acute subdural haematoma without subarachnoid haemorrhage caused by rupture of an internal carotid artery bifurcation aneurysm: case report and review of literature.

Spontaneous pure acute subdural haematoma (ASDH) without intraparenchymal or subarachnoid haemorrhage caused by a ruptured cerebral aneurysm is extremely rare. To our knowledge, the present case is the first report of an internal carotid artery bifurcation aneurysm presenting as pure ASDH. Suitable diagnostic investigations and therapeutic strategies are discussed. Arterial origin of bleeding should be considered in all cases of non-traumatic ASDH and a vascular anomaly has to be excluded. The neurological status on admission dictates the appropriate timing and methodology of the neuroradiological investigations.

Extraventricular neurocytoma presenting with intratumoral hemorrhage.

A case of extraventricular neurocytoma with spontaneous intratumoral hemorrhage is reported. A 47-year-old man presented with sudden left-sided hemiparesis. Magnetic resonance imaging revealed a right parietal subcortical mass with intratumoral hemorrhagic transformation and without contact to the ventricular system. After complete microsurgical removal, the tumor was histologically diagnosed as neurocytoma. Usually, the term "central neurocytoma" is restricted to neurocytic neoplasms arising within the cerebral ventricles. In the majority of the cases, these slow-growing, generally circumscribed lesions become symptomatic by obstructive hydrocephalus. Hemorrhagic onset is sporadically reported in the literature. In contrast to central neurocytomas, neurocytic lesions located within the brain parenchyma, so-called "extraventricular neurocytomas" are very uncommon. To the knowledge of the authors, this is the first case of an extraventricular neurocytoma with histological classic features presenting with intratumoral hemorrhage in adults.

Meningioma of the accessory nerve extending from the jugular foramen into the parapharyngeal space.

A 35-year-old man presented with pain in the right shoulder and neck for 18 months. The neurological examination revealed complete accessory nerve palsy on the right side without further deficits. Magnetic resonance imaging showed a right parapharyngeal tumour expanding into the posterior fossa through the jugular foramen without dural attachment and absence of invasion into the middle ear cavity or internal auditory meatus. Intraoperative inspection disclosed a tumour originating from the accessory nerve. Histological diagnosis revealed a meningothelial meningioma with invasion of the epineural space. To the knowledge of the authors this is the first report of an accessory nerve meningioma in the jugular foramen associated with a posterior fossa component and extension into the parapharyngeal space.

Novel retractor for endoscopic and microsurgical spinal interventions.

Retractors play an important role in surgery, especially using endoscopic techniques like microendoscopic discectomy. As a consequence of the minimally invasive approach the working space is frequently very restricted. All currently available systems still use tubular retractors with limitations regarding flexibility, stability and accessible working space. This paper discusses the technical aspects of a newly designed circular retractor system for endoscopic and microsurgical spinal interventions (SpineGate) and presents first clinical results in a series of 20 consecutive patients. The autoclavable system consists of a circular base plate and several valves varying in length. The variable fixation of the valves from different directions within the 360 degrees geometry of the base plate allows a continuously adjustable working space, depending on the individual anatomy. An additional fixation device is not necessary. The retractor is suitable for microendoscopic and microsurgical techniques. It is easy and safe to handle. The retractor system was successfully used in all cases without complications or instrumental malfunctions. All patients experienced good to excellent relief of their preoperative symptoms.

Primary melanocytic lesions of the CNS: report of five cases.

Primary melanocytic tumours of the central nervous system (CNS) form a rare entity which is histologically and clinically distinct from metastatic cutaneous or retinal malignant melanoma. They can be classified into diffuse melanocytosis (diffuse melanosis), malignant melanoma and benign melanocytoma with a small number of intermediate variants. In this paper, 5 cases treated neurosurgically in our department for spinal or cerebral primary CNS malignant melanoma are reported. Primary tumors and further metastases were ruled out. Radiological, histological and clinical features are discussed. Compared to metastatic disease, primary CNS malignant melanoma shows a more benign clinical course with long-term tumour control and a good quality of life. A review of the literature which mainly consists of individual case reports, confirms this assessment. Although therapeutic experience for primary melanocytic lesions of the CNS is based on a small number of published cases, prognosis seems highly dependent on complete tumour resection. Adjuvant radiation seems to be of additional therapeutic benefit. Except for meningeosis melanomatosa chemotherapy must be regarded as experimental. Unfortunately, a standardised therapy concept is still lacking.

Anatomy of the cerebral ventricular system for endoscopic neurosurgery: a magnetic resonance study.

BACKGROUND: Endoscopy has developed into an integral part of minimally invasive neurosurgery. For further technological innovations, detailed knowledge about the pathological anatomy is essential. The gross anatomy of the cerebral ventricular system has been meticulously investigated with ventriculography and casts. Extensive volumetric measurements based on neuroradiological images have been performed, but only little is known about the surgically relevant linear distances in patients with hydrocephalus. METHOD: Thirty healthy volunteers and thirty patients suffering from hydrocephalus were scanned with high-resolution 3-D magnetic resonance imaging sequences. The image volumes were sliced identically with the help of Siemens Prominence software. Individual anatomical measurements of the ventricular system were carried out, mean values and standard deviations were calculated, and different endoscopic approaches were investigated. FINDINGS: In healthy volunteers the measurements confirmed the results obtained from ventriculography and anatomic casts. In hydrocephalic patients the ventricular system was found to be enlarged asymmetrically. The optimal neuroendoscopic approach showed considerable, interindividual variation. INTERPRETATION: This 3-D magnetic resonance imaging study revealed surgically and clinically relevant aspects of the pathologic anatomy of hydrocephalic patients, in comparison to healthy volunteers. Individualized planning of the endoscopic approach appears to be warranted. Finally, the data provided a sound basis for the further development of neuroendoscopes.

Relevance of image fusion for target point determination in functional neurosurgery.

BACKGROUND: For the treatment of medically refractory movement disorders such as Parkinson's disease, essential tremor and primary dystonia, deep brain stimulation (DBS) has become one of the main treatment options. The targets for implantation of the stimulation electrodes are various nuclei within the basal ganglia or the thalamic and subthalamic area. Accurate target localisation is of major importance for outcome and patient safety. The goal of this study was to evaluate the role of image fusion in the determination of target co-ordinates. METHOD: We conducted a retrospective study on 10 patients in whom 17 DBS electrodes had been implanted. Coordinates of the anterior and posterior commissures and of the DBS targets were compared on pre- and postoperative computerised tomography (CT) and fused CT/magnetic resonance scans. The targets as defined on the images were further compared with the targets derived intra-operatively with microelectrode recordings (MER) and macrostimulation. FINDINGS: The achievable mean target accuracy was of the order of the diameter of the DBS electrode and of the accuracy of the image fusion algorithm, i.e. about 1 mm. However, the maximal differences were between 1.8 mm and 3.2 mm. INTERPRETATION: Image fusion is a helpful tool for accurate determination of target point co-ordinates in DBS. In combination with intraoperative, electrophysiological recordings and stimulation which are still considered to be the most reliable localisation methods, image fusion may help to discern the anatomical and functional three-dimensionality of the target nuclei. Image fusion may reduce the number of trajectories needed for intraoperative electrophysiological determination of the optimal electrode localisation and thus lower the risk of complications.

MRI features of primary, secondary and metastatic medulloblastoma.

Medulloblastoma is the most frequent paediatric malignant brain tumour. The purpose of this study was to define imaging characteristics and contrast uptake patterns of primary and recurrent medulloblastoma using MRI. The MRI examinations of 17 histologically proven cases of medulloblastoma diagnosed in our institution (13 males and 4 females; mean age 13 years, 7 months) were reviewed in retrospect. Only patients with pre-treatment and follow-up examinations including T2-weighted images (fluid-attenuated inversion recovery or turbo spin echo) and T1-weighted images after contrast injection (0.1 mmol/kg Gd-DTPA) were included in this study. Whereas 6 of 7 tumours ( n=17) were hyperintense on T2-weighted images, contrast enhancement was detected in 13 patients. Fifteen tumours occurred in the cerebellar vermis, two were located in the cerebellar hemispheres. Mean size at the time of presentation was 30.1 mm. All patients presented with some extent of an occlusive hydrocephalus. Local recurrent tumour or metastases were seen in 6 patients (3 months to 7 years, mean age 2.5 years). Whereas the T2 signal intensity of recurrent tumour or subarachnoidal metastases resembled the primary neoplasms, the contrast uptake tended to be less pronounced ( n=3) or was completely absent ( n=2); thus, suggestive signs of primary medulloblastoma are location in the vermis, hyperintensity on T2-weighted images and hydrocephalus. The amount of contrast enhancement is variable and nonspecific. Secondary medulloblastoma manifestation is characterized by T2 hyperintensity but not by contrast uptake.

Combined therapy of cerebral arteriovenous malformations: histological differences between a non-adhesive liquid embolic agent and n-butyl 2-cyanoacrylate (NBCA).

OBJECTIVE: Based on 2 casuistics, the intraoperative qualities of a new, non-adhesive liquid embolic agent (Onyx, Micro Therapeutics. Inc., Irvine, CA, USA) are to be compared to those of n-butyl 2-cyanoacrylate (NBCA) with regard to the histopathological results after preoperative embolization of a cerebral arteriovenous malformation (AVM). PATIENTS AND METHODS: In a case example, the intraoperative quality of the nidus after embolization of a parieto-occipital AVM with Onyx--a new, non-adhesive liquid embolic agent--consisting of ethylene-vinyl alcohol copolymer (EVOH), dimethyl sulfoxide (DMSO) and tantalum, is described. In the second patient, embolization of a frontal high-flow AVM was performed with NBCA. Both patients underwent surgery with complete resection ofthe AVM. RESULTS: From a neurosurgical point of view, Onyx is suitable for preoperative embolization of AVMs, because the nidus intraoperatively remains elastic and formable and can be dissected from the surrounding brain tissue quite well by microsurgical technique. Inflammatory reactions can be found mainly in the lumina of the vessels. CONCLUSIONS: Onyx promises to be an embolic agent well suitable for subsequent neurosurgical resection. Further studies considering various intervals of time between embolization and resection as well as histopathological and electron microscopical examinations are necessary for evaluation of our first experience with this new embolization agent.

New virtual system for planning of neuroendoscopic interventions.

OBJECTIVE: The demands on virtual planning systems are increasing, particularly for technically pretentious surgical interventions such as intracranial endoscopy. In this article, a new virtual system for neuroendoscopy (VIVENDI) is presented. The main purpose of this system is to provide support for planning and training in neuroendoscopic interventions. MATERIALS AND METHODS: The software is applied for virtual endoscopic visualization of three-dimensional magnetic resonance datasets, using a clinical magnetic resonance scanner. Rendering is performed on a Hewlett-Packard UNIX workstation. RESULTS: Virtual endoscopy provides a three-dimensional view of the cerebral ventricles, with good visualization of anatomic details. The rendering system used allows the generation of fly-through sequences for the entire ventricular system in real time. Navigation is controlled by mouse movements, and the visualization of the computer-generated intraventricular spaces is adapted to the characteristics of the optical endoscope. CONCLUSIONS: The presented virtual neuroendoscopy system is a promising tool for planning and training in neuroendoscopic procedures. It enables these procedures to be simulated prior to surgery based on the patient's individual anatomy.

Spontaneous occlusion of a cerebral arteriovenous malformation: angiography and MR imaging follow-up and review of the literature.

We present the angiographic and MR imaging course of a 62-year-old man with a right parietal high-flow arteriovenous malformation (AVM), which was diagnosed because of seizures. A spontaneous, complete, and asymptomatic occlusion of the AVM was confirmed by a second angiography 3 months later. The possible mechanisms leading to the occlusion are discussed, and a brief review of the literature is given.

Quality planning for minimally invasive procedures in neurosurgery.

Parallel to the introduction of a minimally invasive method in a department, a documentation system should be introduced for quality management. The first step of quality management of an innovation is quality planning. During the course of patients being treated neuroendoscopically, the pre- and postoperative imaging, the intraoperative video recording, the patient-relevant files and the data of the planning have to be documented. These amounts of data require a multimedial documentation concept. We found the CD-ROM as an optimal documentation media because the discs are both cheap and easily accessible and once stored extremely robust against external influences. Therefore, every neuroendoscopically treated patient is documented with all relevant pictures, files and video sequences on a single CD-ROM.