0000000000016157
AUTHOR
P. Grunert
Concept and Treatment of Hydrocephalus in the Greco-Roman and Early Arabic Medicine
In the ancient medical literature hydrocephalus was not often described although its existence and symptomatology were well known. Most detailed descriptions of hydrocephalus including the surgical treatment are extant in the encyclopaedic works on medicine of the physicians Oreibasios and Aetios from Amida from the 4th and 6th centuries AD, respectively. Because of their broad scientific interests, this type of physicians, typical for the late Roman empire, were known as philosophy-physicians (iota alpha tau rho o sigma o phi iota sigma tau alpha iota). They defined hydrocephalus in contrast to our present understanding as a fluid collection excluding abscesses visible as a bulging tumour …
Target point calculation in the computerized tomography. Comparison of different stereotactic methods
The adaptation of computerized tomography for stereotactic operations requires the transformation of the coordinates of the target point from the CT image space into the stereotactic frame space. Two basic solutions for this transformation are realized in the most of the contemporary stereotactical systems. The indirect geometric method adjusts the frame coordinate system mechanically and identifies its origin in the CT image. There are 6 degrees of freedom: 3 of rotation and 3 of translation which have to be taken into consideration. The second method is a based on direct algebraic coordinate transformation and is independent of the explicite knowledge of the relationship between the image…
Frameless Neuronavigation Applied to Endoscopic Neurosurgery
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…
Bovine pericardium for duraplasty: clinical results in 32 patients.
Bovine pericardium has been widely used for grafts in cardiac surgery and seems to have suitable properties for use as a dural graft. We report on the use of solvent-preserved, gamma-sterilized Tutoplast bovine pericardium for dural grafts in 32 patients undergoing cranial and spinal operations with the objective of clinically assessing this material and technique by a retrospective analysis. All available records were reviewed and information regarding the indication for grafting, complications, and outcome were collected and analyzed for all patients. Indications for grafting included tethered cord myelolysis, closure of lumbosacral myeloceles, Chiari decompression, posterior fossa cranio…
Intraoperative Topographische Diagnostik bei kortikalen Tumoren in der Sprach- und Zentralregion
Exstirpation von kortexnahen Tumoren in der Sprach- und Zentralregion birgt die Gefahr einer postoperativen neurologischen Verschlechterung. Intraoperativ ist die rein anatomisch topographische Planung des Zuganges nicht ausreichend, um diese Kortexareale funktionell genau zu lokalisieren und auszusparen. Aus diesem Grund erscheint es wichtig, wahrend der Operation die sprachrelevanten Areale sowie die fur die Motorik essentiellen kortikalen Bereiche exakt zu lokalisieren und ihre Ausdehnung zu bestimmen. Dies kann durch elektrische Stimulation des Kortex unmittelbar nach der Eroffnung der Dura mater erfolgen. Bei Eingriffen in der Sprachregion mus berucksichtigt werden, das die Uberprufung…
Endoscopic Procedures through the Foramen Interventriculare of Monro under Stereotactical Conditions
The foramen interventriculare of Monro is an anatomical narrowness for the endoscopic access to the third ventricle. The effective mechanical angle to pass the foramen interventriculare from a frontal bore hole depends on the diameter in the plane of entrance, the depth of the foramen, and the diameter of the endoscope. Under the pathological conditions of a hydrocephalus internus the foramen interventriculare is enlarged. By means of stereotactical guidance, it is possible to reach the third ventricle accurately without damaging anatomical structures around the foramen interventriculare. The endoscopic technique under stereotactical guidance using a rigid endoscope is sufficient and safe t…
Computer-aided navigation in neurosurgery
The article comprises three main parts: a historical review on navigation, the mathematical basics for calculation and the clinical applications of navigation devices. Main historical steps are described from the first idea till the realisation of the frame-based and frameless navigation devices including robots. In particular the idea of robots can be traced back to the Iliad of Homer, the first testimony of European literature over 2500 years ago. In the second part the mathematical calculation of the mapping between the navigation and the image space is demonstrated, including different registration modalities and error estimations. The error of the navigation has to be divided into the …
Mesencephalic ependymal cysts: treatment under pure endoscopic or endoscope–assisted keyhole conditions
Object Primary intracranial ependymal cysts are extremely rare. Similar to congenital intraparenchymal cysts in the mesencephalon they usually occur with symptoms of an occlusive hydrocephalus or symptoms like Parinaud syndrome, dizziness, or gait disturbance. The objective of this study was to evaluate the surgical methods for the treatment of these cysts and the clinical outcome of the patients. Methods The authors present the clinical records of 8 patients who were treated in their department for symptomatic mesencephalic ependymal cysts in the past 10 years. The patient age ranged from 22 to 60 years with a mean age of 44 years. In 4 cases the authors performed a suboccipital infratent…
Results of 200 intracranial stereotactic biopsies
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…
Stereotaktische Biopsie von Hirntumoren: Vergleich von CT-und MR-gesteuerter Berechnung
Bei 3 Patienten mit Hirntumor wurde eine stereotaktische Biopsie nach Zielpunktberechnung uber Computertomographie (CT) und Magnetresonanztomographie (MR) durchgefuhrt. Die beiden Techniken werden miteinander verglichen und ihre Vor-und Nachteile diskutiert.
Characterization of BOLD-fMRI signal during a verbal fluency paradigm in patients with intracerebral tumors affecting the frontal lobe.
Previous studies have indicated that the BOLD-fMRI signal can be modified by tumor processes in close vicinity to functional brain areas. This effect has been investigated primarily for the perirolandic area but there is only a limited number of studies concerning frontal cortical regions. Therefore, the aim of the current study was to characterize BOLD-fMRI signal and activation patterns in patients with frontal brain tumors while performing a verbal fluency task. Six patients (ages 31-56 years) suffering from frontal (5 left sided and 1 right sided) intracerebral tumors were examined with fMRI while performing a verbal fluency task in a blocked paradigm design. Eight healthy volunteers se…
Accuracy of stereotactic coordinate transformation using a localisation frame and computed tomographic imaging
The accuracy of coordinate transformation from a CT image to a stereotactic frame was investigated for stereotactic systems using a localisation frame and matrix-based coordinate transformation. The main source of error influencing calculation was input data, due to inaccurate calculation of the centres of the rods of the localisation frame in the CT image, and the propagation of this input error during subsequent matrix calculation. Systemic errors during matrix calculation do not exist, and rounding off errors were of subordinate importance compared to the input data error. The influence of input data error on coordinate transformation was studied by geometric methods, computer simulation…
CT-guided stereotactic biopsy aided by Doppler ultrasonic vascular monitoring
The use of a 20 MHz pulsed Doppler technique during stereotactic brain tumour biopsies is described. By means of a miniaturized ultrasonic probe the tissue planned for biopsy was investigated for vessel signals. Out of 41 patients, with this technique a flow-pulse curve in front of the biopsy cannula was registered in 14 cases. In 9 cases one pulse curve was determined and in 5 cases two or more flow curves were found, indicating the presence of arterial vessels. The depth of the vessels signal could be localized and this area avoided for biopsy sampling. In a series of 41 stereotactic biopsies carried out in this way there was no intra-operative haemorrhage or postoperative haematoma.
Stereotactic biopsies guided by an optical navigation system: technique and clinical experience.
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…
Accuracy of stereotactic coordinate transformation using a localisation frame and computed tomographic imaging
The accuracy of coordinate transformation from the computed tomographic (CT) space to the stereotactic frame space was analysed for frame-based stereotactic systems which use a localisation frame and coordinate transformation based on matrix calculation. The coordinate transformation was divided into three consecutive steps: (1) transforming the localisation frame into the CT image built up from pixels with distinct attenuation values, (2) determining the rod centres of the localisation frame in the CT image, and (3) coordinate transformation from the image to the frame space using the centres of the rods in the image space and algebraic, matrix-based calculation. The error contribution at …
Frame-based and frameless stereotaxy in the localization of cavernous angiomas
Cavernous angiomas are mostly small intracranial vascular lesions which can be intraoperatively localized by sonography or stereotactic methods. This paper compares the results of cavernous angioma surgery localized by frame-based vs frameless techniques. Thirty-nine patients with cortical or subcortical lobar cavernoma were operated on by a microsurgical trans-sulcal approach. The localization of the lesion was performed in 19 (49%) patients by frame-based technique and in 20 (51%) patients by frameless navigation. In 22 (56%) of the patients, the cavernomas were located in an eloquent cortical area. Ten of 22 of these lesions were localized by frame-based stereotaxy and 12/22 by frameless…
Stereotactically guided cavernous malformation surgery.
The incidence of a significant hemorrhage in the natural history of cavernomas is below 1% per year, but the risk of a second hemorrhage in patients with initial bleeding cavernomas is between 14% and 29%. In the light of these figures, all cavernomas ought to be resected if surgical-related morbidity can be minimized. Stereotactically guided neurosurgery offers the advantage of planning the least traumatic approach before craniotomy due to the knowledge of the exact localisation of the lesion. During a 2-year period 12 patients (age 16-54 years) with intracranial supratentorial cavernomas (size 0.5-1.8 cm) were treated by stereotactically guided microsurgery. The cavernomas were seated in …
The Role of Third Ventriculostomy in the Management of Obstructive Hydrocephalus
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 …
Vascular Decompression of Trigeminal and Facial Nerves in the Posterior Fossa under Endoscope-Assisted Keyhole Conditions
Objective: The aim of this study was to determine the use and safety of the endoscope as an adjunct during trigeminal and facial nerve decompression procedures performed under keyhole conditions in the posterior fossa. Method: We performed 67 surgeries in 65 patients with symptomatic trigeminal and facial nerve compression syndromes. The diagnosis was made mainly on the basis of clinical history, examination, and magnetic resonance imaging scans. Surgery was performed in all cases under endoscope-assisted keyhole conditions. The follow-up was 1 week postoperatively, 6 months, and then yearly up to 7 years. All 34 patients with trigeminal neuralgia received preoperative medication treatment …
German neuroendoscopy above the skull base
Endoscopy plays an important part in current minimally invasive neurosurgery. The concepts, indications, and standards of current neuroendoscopy were developed in the beginning of the 1990s by several groups of neurosurgeons. Several factors contributed to its success and acceptance, including technical development, influence of other disciplines, and adaptation to neurosurgical requirements. This historical survey focuses on the period when this technique initially emerged, including the scientific discussions of each group as well as the arguments and reasons that led to present intraventricular neuroendoscopy. Interestingly, despite the almost independent development of neuroendoscopic s…
Endoscopic Third Ventriculostomy: Outcome Analysis of 100 Consecutive Procedures
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…
Re-ventriculostomy for treatment of obstructive hydrocephalus in cases of stoma dysfunction.
In this article, 12 re-ventriculostomies in the treatment for obstructive hydrocephalus are described. The etiology of the hydrocephalus was a benign aqueductal stenosis in 9 patients, a tumor around the aqueduct in 2 patients and intraventricular bleeding in one patient. In all cases the initial ventriculostomy was successful, but after a time interval of 2 weeks to 6 years the patients developed similar clinical symptoms as preoperatively. In all except one case the radiological findings spoke in favour of stoma closure. Intraoperatively the stoma was completely closed in 9 patients and in 3 patients a subtotal closure was observed. In all cases a re-ventriculostomy was performed bluntly …
Neuronavigation and epilepsy surgery
Resective epilepsy surgery is an elective therapy indicated in focal epilepsy patients who are resistant to pharmacotherapy. Every effort should be undertaken to perform the procedures as safe and less traumatic as possible. Neuronavigation could represent a suitable tool to reduce surgical morbidity and increase surgical radicality. Here, we present a series of 41 patients who were operated on for medically intractable epilepsy using neuronavigation. Overall, complication rate was 17% with a favourable seizure outcome of 88% (Engel’s class I/II). Our data suggest that neuronavigation is a valuable surgical technique to accomplish a favourable outcome in epilepsy surgery.
Frame-based and frameless endoscopic procedures in the third ventricle.
Stereotactic guidance is useful for planning an accurate trajectory to the third ventricle. A guiding block with a ball joint was developed for frame-based endoscopy and adaptors for arm-based and armless navigation systems. Between 1992 and 1996, 52 patients were operated on endoscopically in the third ventricle under stereotactic guidance. Thirty-eight ventriculostomies, 13 biopsies and 10 cystic lesions were performed. The coordinates of two points were calculated; one in the foramen of Monro and the second in the third ventricle. The ventriculostomy was performed under endoscopic control bluntly with a Fogarty catheter in front of the basilar artery. Twenty-seven (71%) of the patients h…