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Dieter Hellwig

Publications and source records attributed to Dieter Hellwig.

14 recordsLinked to original sources
PubMed2005

Secretory meningioma: immunohistochemical findings and evaluation of mast cell infiltration.

Secretory meningiomas constitute a relatively rare subtype of meningiomas, accounting for only 1.1% at our institution, with a 6:1 predominance of female patients. This study aimed to obtain more information about the immunohistochemical characteristics of this histological entity, and to analyse the effects of histological factors such as the presence of mast cells on the radiological evidence of surrounding tumour oedema that frequently occurred in this subtype of meningioma. Fourteen cases of secretory meningioma were examined. Relevant clinical information was obtained from the patient files. Peritumoural oedema was determined either by CT or MRI scans and graded as small, moderate and severe. In order to perform the quantitative evaluation of mast cells in secretory meningiomas in a comparison with other meningiomas, 14 non-secretory meningiomas were randomly selected and used as a control group. The immunohistochemical staining of carcinoembryonic antigen was positive within the secretory droplets and the cells surrounding them in all cases. Ki 67 (MIB 1) proliferative index mean values were 2.4%, indicating low expression in all secretory meningiomas. Moreover, from our statistical analysis, there is no clear-cut pattern of various types of cytokeratins emerging in secretory meningiomas. The secretory meningiomas were characterized by a significantly increased number of mast cells as compared with non-secretory meningiomas of different grades. As the present clinical findings and laboratory results could not confirm a correlation between mast cell density and radiological evidence of oedema, further studies of mediators are warranted.

Actins↗
PubMed2005

High-resolution constructive interference in steady-state imaging in tethered cord syndrome: technical note.

BACKGROUND: Differentiation between nerve roots and the tethered filum terminale in magnetic resonance images remains challenging. It is, however, crucial to select patients for surgical intervention. METHOD: In 1 patient with progressive and 2 patients with stable clinical signs of tethered cord syndrome (TCS), images reconstructed from a 3D constructive interference in steady-state (CISS) sequence were compared with those obtained from a regular T2-weighted fast spin echo sequence. RESULTS: Nerve roots of the cauda equina were suppressed, whereas visualization of the filum terminale was much improved in high-resolution CISS sequences. In addition, the level of adhesion of the filum could be localized in relation to elements of the spinal cord. The imaging results were confirmed during surgery and the patient improved considerably after the intervention. The advantages of CISS were also apparent in 2 other patients who are still being observed. CONCLUSION: Constructive interference in steady-state imaging should be considered in the presurgical routine for patients with TCS.

Adult↗
PubMed2005

Volumetric image guidance for motor cortex stimulation: integration of three-dimensional cortical anatomy and functional imaging.

OBJECTIVE: Epidural electrical stimulation of the motor cortex is a promising treatment option in patients with intractable pain. Varying rates of success in long-term pain relief have been attributed to inaccurate positioning of the electrode array, partly because the sulcal landmarks are not directly visualized. We describe an integrated protocol for precise electrode placement, combining functional image guidance and intraoperative electrical stimulation in the awake patient. METHODS: Volumetric rendering of a three-dimensional (3-D) magnetic resonance data set was used to visualize the cortical surface and to superimpose functional magnetic resonance imaging data in six patients with refractory chronic pain. The intraoperative positioning of the quadripolar electrode array was monitored by functional 3-D image guidance. Continuous electrophysiological monitoring and clinical assessment of the motor effects complemented the procedure. RESULTS: Volumetrically rendered 3-D images were advantageous for the location of the burr hole over the perirolandic area by revealing individual cortical morphological features (e.g., the hand knob) and function at the same time. The exact position of the electrodes was verified reliably by cortical stimulation. No complications were observed throughout the procedures. CONCLUSION: The combination of 3-D functional neuronavigation, intraoperative electrical stimulation, and continuous motor output monitoring in awake patients provides optimal information for the identification of the appropriate somatotopic area of motor cortex. This combined imaging and stimulation approach for electrode positioning offers a safe and minimal invasive strategy for the treatment of intractable chronic pain in selected patients.

Adult↗
PubMed2005

Enlarged perivascular spaces mimicking multicystic brain tumors. Report of two cases and review of the literature.

The authors present two cases in which enlarged Virchow-Robin spaces were located in the basal ganglia and the thalamomesencephalic region. The incidence of such huge cystic lesions is extremely rare. The expanding nature of these lesions, demonstrated by the patients' progressive symptoms due to compression of the adjacent brain parenchyma and obstructive hydrocephalus, mimicked that of brain tumors. The two patients were successfully treated by neuroendoscopic cystocisternostomy or ventriculocystostomy. To the authors' knowledge there have been only two published reports on expanding Virchow-Robin spaces that produced a compressive effect or consequent hydrocephalus and were directly fenestrated using neuroendoscopic techniques. Neuroendoscopy appears to offer an effective surgical option in the treatment of symptomatic Virchow-Robin spaces.

Basal Ganglia↗
PubMed2004

Endoscopic third ventriculostomy for obstructive hydrocephalus.

The indications for neuroendoscopy are not only constantly increasing, but even the currently accepted indications are constantly being adjusted and tailored. This is also true for one of the most frequently used neuroendoscopic procedures, the endoscopic 3rd ventriculostomy (ETV) for obstructive hydrocephalus. ETV has gained popularity and widespread acceptance during the past few years, but little attention has been paid to the techniques of the procedure. After a short introduction describing the history of ETV, an overview is given of all the different techniques that have been and still are employed to open the floor of the 3rd ventricle. The spectrum of indications for ETV has been widely enlarged over the last years. Initially, the use of this procedure was restricted to patients older than 2 years, to patients with an obvious triventricular hydrocephalus, and to those with a bulging, translucent floor of the 3rd ventricle. Nowadays, indications include all kinds of obstructive hydrocephalus but also communicating forms of hydrocephalus. The results of endoscopic procedures in treating these pathologies are given under special consideration of shunt technologies. In summary, from the review of the publications since the first ETV performed by Mixter in 1923, this technique is the treatment of choice for obstructive hydrocephalus caused by different etiologies and is an alternative to cerebrospinal fluid shunt application.

Age Factors↗
PubMed2004

The evolution of stereotactic guidance in neuroendoscopy.

OBJECTIVES: To evaluate the advantages and limitations of the utilized system in accordance with the operative indications of stereotactic neuroendoscopy. PATIENTS AND METHODS: We reviewed our collective experience of computer-assisted stereotaxy (frame-based and frameless) and virtual endoscopy in neuroendoscopic surgery from 1982 to 2003. Sterotactic guiding systems (frame-based and frameless) have been used to perform more than 450 neuroendoscopic operations at our institute. RESULTS: Even though image guidance is not essential in all cases, technological developments have definitely been one of the major factors in improving outcomes. Planning endoscopic trajectory and intraoperative orientation within the ventricular system or other cavities are the main indications for its application. CONCLUSIONS: No surgical tool, no matter how accurate, can be a substitute for thoughtful and methodical pre-operative planning. Image-guided technologies are applied in order to make endoscopic surgery safer, faster and more easily reproducible. Despite the high initial cost of the equipment, overall expenses are expected to be reduced because of greater operative efficiency and shorter hospital stay.

Adolescent↗
PubMed2004

Neuroendoscopic surgery of intracranial cysts in adults.

OBJECTS: The purpose of this study was to describe the indications, surgical techniques and postoperative outcome of neuroendoscopic interventions in a heterogeneous group of intracranial cystic pathologies. PATIENTS AND METHODS: Between 1992 and 2003, 127 patients with symptomatic intracranial cysts and cystic tumours underwent neuroendoscopic treatment in our department. In 22 patients indication for surgery was colloid cysts, in 9 patients pineal cysts and in 3 patients cavum vergae cysts. Twelve arachnoid cysts, 10 cystic craniopharyngiomas, 2 Rathke's cleft cysts and 69 malignant cystic tumours were operated on. The patients' mean age was 45 years and their clinical presentations varied from typical signs of increased intracranial pressure to focal neurological deficits. RESULTS: One hundred and twenty-seven patients with intracerebral cystic space-occupying lesions were operated on using stereotactic frameless or frame-based endoscopic techniques. There was no operative mortality. The operative morbidity was 3.1% including 1 memory deficit due to fornix injury, 1 hemiparesis due to postoperative haematoma after lesion biopsy, 1 aseptic meningitis and 1 subdural fluid collection. CONCLUSIONS: Endoscopic interventions enable neurosurgeons to manage intracranial cystic lesions. Via the same approach, the obstructed CSF pathways may be restored and consequently the increased intracranial pressure diminishes. With the aid of stereotactic guidance or a neuronavigation system, access to the lesion can be gained rapidly and with high accuracy.

Adult↗
PubMed2004

Neuroendoscopic stent procedure in obstructive hydrocephalus due to both foramina of monro occluding craniopharyngioma: technical note.

BACKGROUND: The development of various neuroendoscopic surgical instruments has offered more options for endoscopic procedures in the treatment of intraventricular tumors. Not only tumor biopsy or tumor resection but also restoration of an obstructed cerebral spinal fluid (CSF) pathway can be performed using the same approach. METHOD: A 76-year-old woman with a cardiac pacemaker for an underlying heart disease was diagnosed with obstructive hydrocephalus because of a third ventricular tumor 8 years ago. The patient had been treated with ventriculo-peritoneal shunt placement. At admission she presented with a subcutaneous infection of the shunt catheter and an abdominal mass of unknown etiology. Neuroendoscopic stenting between lateral and third ventricle was performed to restore the obstructed CSF pathway, and the infected shunt system was removed in the same setting. RESULT: The postoperative course was uneventful. Contrast ventriculography demonstrated a restored CSF pathway between the lateral and third ventricle. Histologic examination of the intraventricular tumor revealed a craniopharyngioma, and the abdominal mass was diagnosed as a gastrointestinal adenocarcinoma. CONCLUSION: The neuroendoscopic foraminoplasty technique should be considered as an alternative treatment for patients who present with an obstructive hydrocephalus caused by a tumor that occludes both foramina of Monro when shunt placement or endoscopic third ventriculostomy is not feasible.

Adenocarcinoma↗
PubMed2003

Neuroendoscopic treatment for colloid cysts of the third ventricle: the experience of a decade.

OBJECTIVE: Microsurgical resection or ventriculoperitoneal shunt placement was for a long time the only means of treatment for patients with colloid cysts. In the past few years, however, endoscopic procedures have gained increasing significance and have been used more widely. Long-term results are now available for the first time, which enabled us to evaluate this method and assess its future relevance. METHODS: Twenty patients with symptomatic colloid cysts of the third ventricle have been treated endoscopically in our department during the past 10 years. Retrospective analysis and follow-up of the patients' clinical and radiological outcomes were performed. RESULTS: In the early postoperative period, 18 patients had excellent outcomes, with clinical signs improving immediately. One patient experienced intraoperative hemorrhage followed by temporary postoperative psychosis and IIIrd cranial nerve palsy. Another patient remained shunt-dependent because of aseptic meningitis after the endoscopic procedure. In the long-term follow-up, one patient had to be reoperated to treat cyst recurrence. The operative time was strongly dependent on the cyst material as well as on the surgeon's experience with endoscopic techniques; it varied between 60 and 300 minutes (mean operative time, 200 min). The average hospitalization time was 9 days. Long-term follow-up ranging from 1 to 10 years showed a clear benefit in each patient. In three individuals with pre- and postoperative short-term memory deficits and in one patient who complained of headaches, symptoms resolved gradually during the first few months after surgery. The patient with intraoperative hemorrhage complained of slight permanent short-time memory deficit. The analysis of postoperative computed tomographic and magnetic resonance imaging scans revealed a remaining cyst wall in the majority of patients and an inconsistent decrease in ventricular size. Postoperative cine magnetic resonance imaging studies showed normalization of cerebrospinal fluid flow in 17 patients. CONCLUSION: Continued improvement of endoscopic techniques and instruments, together with good long-term results in endoscopically treated patients, have established this method as an alternative to microsurgical techniques and might even set a new standard for treatment.

Adolescent↗
PubMed2003

Endoscopic third ventriculostomy for shunt dysfunction in occlusive hydrocephalus: long-term follow up and review.

OBJECT: Endoscopic third ventriculostomy (ETV) is the treatment of choice for occlusive (noncommunicating) hydrocephalus. Nevertheless, its routine use in patients who have previously undergone shunt placement is still not generally accepted. The authors' aim was to investigate the long-term effects of ETV in a group of prospectively chosen patients. METHODS: Patients who underwent ETV and had previously undergone shunt placement for occlusive hydrocephalus were followed prospectively for at least 3 years (range 36-103 months, mean 63.6 months). Nine female and eight male patients ranging from 8 to 54 years of age (mean 32 years) had undergone shunt placement 0.7 to 23.5 years (mean 8.1 years) before ETV. Fifteen patients were admitted with underdrainage and two with overdrainage. In six cases, ETV was performed as an emergency operation. The origin of hydrocephalus was aqueductal stenosis in 12 cases and aqueductal compression by a tumor in two cases. Three patients suffered from a fourth ventricle outlet syndrome, and in two patients an additional malresorptive component was suspected. Thirteen patients underwent ETV with shunt removal and insertion of an external drain in one session. The drain served as a safety measure; it could be opened if raised intracranial pressure or ventricular dilation was observed on postoperative imaging studies. In the other four patients the shunt was initially ligated and then removed during a second operation. Fourteen patients (82%) have remained shunt free. The other three patients, including the two with an additional malresorptive component, needed shunt reimplantation 3 days, 2 weeks, or 7 months after ETV. CONCLUSIONS: Use of ETV is safe and effective for the treatment for shunt dysfunction in patients with obstructive hydrocephalus.

Adolescent↗
PubMed2003

Pontine hemorrhage.

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Cerebral Hemorrhage↗
PubMed2002

Novel multipurpose bipolar instrument for endoscopic neurosurgery.

OBJECTIVE: Hemorrhage control in endoscopic neurosurgery is critical because of the lack of suitable instruments for coagulation. One reason for this problem is that miniaturization of the instruments is still a technical problem. In this article, we present a solution: the use of bipolar microforceps with a small diameter of 1.5 mm. METHODS: With the use of modern synthetic and metallic materials, the construction of the bipolar microforceps was designed without the use of mechanical joints. All movable elements are integrated within the instrument shaft. This design provides optimal visibility of the operating field because the sheath has a diameter of only 1.5 mm along its entire length. Therefore, this instrument is compatible with most working channels of neuroendoscopes. RESULTS: The new, joint-free design of the forceps and the electric insulation of the branches were the technical innovations that led to the development of this novel, multipurpose instrument. CONCLUSION: This new instrument may enhance endoscopic resection and shrinkage of cystic lesions and may offer new possibilities in endoscopic tumor resection and the treatment of hemorrhage.

Adult↗