0000000000016156
AUTHOR
Nikolai J. Hopf
showing 14 related works from this author
Localization of emotional and volitional facial paresis.
1992
Emotional facial paresis is characterized by impaired activation of face muscles with emotion but normal voluntary activation. We report seven patients with this sign. Their lesions involved the frontal lobe white matter, the striatocapsular territory, the anterolateral thalamus and insula, the posterior thalamus and operculum, and the mesial temporal lobe and insula each in one patient, and the posterior thalamus in two patients. Volitional facial paresis affects facial movements with voluntary effort, sparing activation on emotion. We report four such patients, with lesions involving the motor cortex in one and the pyramidal tract in the cerebral hemisphere in three.
Frameless Neuronavigation Applied to Endoscopic Neurosurgery
2000
Objective: We retrospectively analyzed the indications, surgical techniques, and applicability of frameless neuronavigation to endoscopic procedures in a heterogeneous group of 15 patients. Material and Methods: In 8 patients indications for surgery were cystic lesions, in 3 patients intraventricular tumors, and in 4 patients occlusive hydrocephalus. The mean age was 39 years (range 9 - 76 years). The follow-up period ranged from 5 - 24 months (mean 10 months). Frameless neuronavigation was accomplished with the “operating arm system” in 10 cases and with the “optical tracking system” in 5 cases (RADIONICS, Burlington, USA). Results: In all 15 cases, neuronavigation sufficiently provided an…
Endoscopic Neurosurgery “Around the Corner” with a Rigid Endoscope. Technical Note
1999
Endoscopically "working around the corner" is presently restricted to the use of flexible endoscopes or an endoscope-assisted microneurosurgical (EAM) technique. In order to overcome the limitations of these solutions, endoscopic equipment and techniques were developed for "working around the corner" with rigid endoscopes. A steering insert with a 5 French working channel is capable of steering instruments around the corner by actively bending the guiding track and consecutively the instrument. A special fixation device enables strict axial rotation of the endoscope in the operating field. Endoscopic procedures "around the corner", including aqueductal stenting, pellucidotomy, third ventric…
Results of 200 intracranial stereotactic biopsies
1994
200 stereotactic biopsies were evaluated. The validity of the intraoperative histopathological results were compared with the final diagnosis using conventional embedding and staining techniques. Further comparison between the histology of the biopsy and the post mortem or open operative findings were possible in 41 cases. Discrepancy was found in one case regarding the tumor detection, and in three cases regarding the tumor grading. The mortality in our patients was 1% and the morbidity 3%. Stereotactical biopsy had a low risk even in deep brain regions such as basal ganglia, mesencephalon, and pons. At the same time the high histologic validity makes the CT-guided stereotactical biopsy re…
The minimally invasive supraorbital subfrontal key-hole approach for surgical treatment of temporomesial lesions of the dominant hemisphere
2009
INTRODUCTION: Surgery in the temporomesial region is generally performed using a subtemporal, transtemporal, or pterional-transsylvian approach. However, these approaches may lead to approach-related trauma of the temporal lobe and frontotemporal operculum with subsequent postoperative neurological deficits. Iatrogenic traumatisation is especially significant if surgery is performed in the dominant hemisphere. METHODS: During a five-year period between January 2003 and December 2007, we have approached the temporomesial region in 21 cases via the supraorbital approach. In 15 cases, the lesion was located within the dominant hemisphere, all lesions had space-occupying effects. In all cases, …
Endoscopic Treatment of Mesencephalic Ependymal Cysts: Technical Case Report
1998
OBJECTIVE: To evaluate the results of different neuroendoscopic surgical procedures for the treatment of mesencephalic ependymal cysts. METHODS: The clinical records of five patients treated for symptomatic mesencephalic ependymal cysts were retrospectively studied. Two patients had been operated on using an endoscope-assisted microsurgical technique and three patients using a pure endoscopic procedure. RESULTS: Adequate fenestration of the cysts was achieved in all of the patients. Two of the patients were symptom-free, and the other three had improved significantly after a mean follow-up duration of 14 months. There was no surgical morbidity. CONCLUSION: Mesencephalic ependymal cysts can …
Stereotactic biopsies guided by an optical navigation system: technique and clinical experience.
2002
Frame-based stereotactic biopsies are time-consuming procedures making necessary head fixation in a ring, explicit coordinate calculation and setting of the parameters. Frameless systems make many of these intermediate steps unnecessary, impose less mechanical restrictions regarding access to the lesions, and with slight modifications can be used to perform stereotactic biopsies. A special adaptation designed to fix the holder and the biopsy instrument is described. The neuronavigation optical tracking system of Radionics was used. CT scans were performed with 6 skin markers. Calibration was performed after head fixation in the Mayfield clamp. Mean calibration error was 2.19 +/- 0.81 mm. Th…
The supraorbital endoscopic approach for aneurysms.
2013
Objective To review our surgical experience in minimally invasive transcranial endoscope-assisted microsurgical treatment of intracranial aneurysms, using the supraorbital keyhole craniotomy. Methods The supraorbital keyhole approach was performed through an eyebrow skin incision in 793 cases for treatment of 989 intracranial aneurysms. Of patients, 474 were operated on after subarachnoid hemorrhage, and 319 were operated on under elective conditions. After lateral frontobasal burr hole trephination, a limited subfrontal craniotomy was created. To achieve adequate intraoperative exposure through the limited approach, endoscopes were used routinely. Surgical outcome was assessed using the mo…
The keyhole concept in aneurysm surgery: results of the past 20 years.
2011
Item does not contain fulltext BACKGROUND: Improvements in preoperative imaging and intraoperative visualization have led to a refinement in surgical techniques. OBJECTIVE: Report of a 20-year experience with application of the keyhole technique as a contribution to the ongoing debate on the impact of limited craniotomies in aneurysm surgery. METHODS: Over a 20-year period, 1000 consecutive patients with 1297 aneurysms were surgically treated in 1062 operations: 651 in the acute stage after SAH and 411 with unruptured aneurysms. The outcome was assessed with the modified Rankin scale and approach-related complications. RESULTS: The majority of the cases were treated by 4 different keyhole a…
The Role of Third Ventriculostomy in the Management of Obstructive Hydrocephalus
2003
Objective: Endoscopic third ventriculostomy (ETV) is an effective treatment for occlusive hydrocephalus caused by an obstruction of the CSF flow in the aqueduct or the posterior fossa. We evaluated the factors age, pathology and surgical technique on the results of the ETV. Methods: Between November 1992 and October 2000 171 ETV have been performed in 159 patients. The follow-up was evaluated in 150 patients. The age ranged from 10 days to 77 years (mean age 35 years). The hydrocephalus was caused by benign aqueductal stenosis in 77 patients, space-occupying lesions in 59, by intraventricular hemorrhages in 11, and by other causes in 3 patients. The trajectory was planned in 31 patients by …
Endoscopic Neurosurgery and Endoscope-assisted Microneurosurgery for the Treatment of Intracranial Cysts
1998
Objective Different endoscopic techniques have been introduced into neurosurgery, but accepted terminology and definitions are still missing. We propose a terminology based on whether the endoscope is used alone or in conjunction with an operating microscope and on whether the route of surgical manipulations is through or outside the endoscope. Accordingly, procedures are categorized into endoscopic neurosurgery (EN), endoscope-assisted microneurosurgery (EAM), and endoscope-controlled microneurosurgery (ECM). Methods We treated 36 patients with intracranial arachnoid cysts (ACs) and intraventricular cysts endoscopically. The patients ranged in age from 4 months to 69 years (mean age, 31 yr…
Endoscopic Third Ventriculostomy: Outcome Analysis of 100 Consecutive Procedures
1999
OBJECTIVE: Endoscopic third ventriculostomy (ETV) has been shown to be a sufficient alternative in the surgical treatment of occlusive hydrocephalus. To elucidate the ongoing discussion of timing, indication, and surgical technique, a retrospective analysis of 100 consecutive ETVs was conducted. METHODS: One hundred ETVs were performed in 95 patients (43 female and 52 male patients). Their age ranged from 3 weeks to 77 years (mean age, 36 yr). Hydrocephalus was caused by aqueductal stenosis in 40 patients, space-occupying lesions in 42, and intraventricular or subarachnoid hemorrhage in 8. One patient had postinflammatory hydrocephalus, and four patients had occlusive hydrocephalus of unkno…
Image Analysis of Proliferating Cells in Tumors of the Human Nervous System
1994
Obtaining growth fractions from immunohistological preparations by the commonly used cell count calculation method is time consuming. For the first time, we investigated and compared the detection of proliferating cells in immunohistologically labeled tissue from tumors of the nervous system using the monoclonal antibody Ki-67 by a new computerized image analysis system and by cell count calculation. The two methods showed a high correlation (correlation index, 0.98) in 37 gliomas (2 pilocytic astrocytomas, 10 Grade II astrocytomas, 5 Grade III astrocytomas, 20 Grade IV astrocytomas and glioblastoma multiforme) and a heterogenous group of 10 additional tumors of the nervous system, includin…
Experimental emetine myopathy: enzyme histochemical, electron microscopic, and immunomorphological studies.
1993
Ipecac, containing emetine hydrochloride, is used by patients with anorexia nervosa to induce vomiting. Its chronic usage may result in a myopathy and a cardiomyopathy, the former marked by cytoplasmic bodies. We studied myopathological changes after daily injections of female Wistar rats with emetine hydrochloride intraperitoneally for periods of 4, 5, 9, and 10 weeks. the extensor digitorum longus muscle and the soleus muscle showed core-like lesions, streaming of the z-discs, nemaline bodies, cytoplasmic bodies, and spheroid cytoplasmic bodies. Immunomorphological studies revealed increased amounts of desmin. During a period of repair, i.e., 2, 4, and 6 weeks after termination of emetine…