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Biomedical subjects

J M Gilsbach

Publications and source records attributed to J M Gilsbach.

At least 55 records · Page 3Linked to original sources
PubMed2002

Microvascular decompression of a developmental venous anomaly in the cerebellopontine angle causing trigeminal neuralgia.

We describe an apparently unique case of a patient with a trigeminal neuralgia caused by compression of the trigeminal nerve during its course by the draining vein of a developmental venous anomaly in the cerebellopontine angle. Typical symptoms of trigeminal neuralgia disappeared completely after microvascular decompression of the nerve. Neuroradiological findings, as well as particularities of this case are described and therapeutic options are discussed.

Adult↗
PubMed2002

What is the ideal initial valve pressure setting in neonates with ventriculoperitoneal shunts?

In order to determine the optimal valve pressure setting during the first weeks in neonates after implantation of programmable Hakim valves and to analyze the benefits and possible side effects of a new treatment protocol in this age group, we performed this prospective study. In 20 consecutive newborns less than 5 weeks of age with hydrocephalus due to various etiologies, a ventriculoperitoneal shunt with a programmable Hakim valve at an extremely low initial valve pressure setting of 30-40 mm H(2)O was implanted. This "overdrainage" was maintained, monitored by regular clinical examination and transcranial ultrasonographic imaging, until the wound healing was uneventfully completed and the permanent valve pressure setting of 100-120 mm H(2)O was chosen. In this age group, which is prone to specific noninfectious shunt complications like wound breakdown, cerebrospinal fluid (CSF) fistula and subcutaneous CSF collections, none of these complications were seen, nor were there any persisting overdrainage phenomena on transcranial ultrasonography. Initial, temporary "overdrainage" represents a simple, useful and risk-free therapy in neonates with programmable shunts which might lower the incidence of typical noninfectious complications in this age group.

Brain↗
PubMed2002

Prognostic factors for patients with microsurgically resected brain metastases.

BACKGROUND: With the advent of new therapies for metastatic carcinoma to the brain, patterns of intracranial disease and factors influencing survival become important considerations when examining treatment options. This study was conducted at a single institution to determine prognostic factors for tumor response and patient survival after microsurgical resection of brain metastases. PATIENTS AND METHODS: 187 consecutive patients who underwent microsurgical resection of brain metastases between July 1989 and September 1996 were retrospectively reviewed and statistically analyzed. The primary cancers included lung cancer (85), gastrointestinal cancer (20), renal cell cancer (19), breast cancer (17), malignant melanoma (8) and 38 cases of various other carcinomas or of unknown primary site. 111 patients received whole-brain radiation therapy (WBRT) with a mean dose of 32 Gy after tumor resection. The influence of number, size, and localization of brain metastases as well as histology of the primary tumor, preoperative performance status, presence of extracranial systemic disease, time course and adjuvant radiation therapy were statistically evaluated (uni- and multivariate) as prognostic factors for survival. RESULTS: Early postoperative Karnofsky score was improved in 59%, unchanged in 32% and worse in 9% of patients. Median survival time (MST) was 9.8 months (range 1 day-5.3 years). The most important parameter showing a significant influence on survival time was the histology of the primary tumor, with prediction of a bad outcome especially for patients with metastases from renal-cell cancer and malignant melanomas. Patients with breast cancer showed longer survival than patients with other primary cancers. Furthermore, survival varied significantly depending on location of brain metastases, performance status at time of craniotomy and duration of symptoms. None of the other studied variables gained prognostic significance. CONCLUSION: Microsurgical resection of one or more brain metastases followed by WBRT still is a useful and efficient treatment in a carefully selected patient group to prolong median survival and improve or stabilize the performance status. Among the factors determining the survival times in this patient group, histology of the primary tumor is most important, together with preoperative Karnofsky score, location of metastasis and preoperative duration of symptoms.

Adult↗
PubMed2001

In vivo 3D visualization of normal pyramidal tracts in human subjects using diffusion weighted magnetic resonance imaging and a neuronavigation system.

We describe the potential of anisotropic diffusion weighted imaging to visualize the course of large cerebral fiber tracts. Five healthy volunteers were investigated at a field strength of 1.5 Tesla, employing a spin-echo diffusion weighted sequence with gradient sensitivity in six non-collinear directions to visualize the course of the pyramidal tracts. The pyramidal tracts were segmented and reconstructed for three-dimensional visualization. Reconstruction results together with a fusioned high resolution 3D T1 weighted image data set were available in a customized neuronavigation system. Origination in the primary motor cortex, convergence in the centrum semiovale, the posterior limb of the internal capsule, the cerebral peduncles, the splitting at the level of the pons, and the pyramidal decussation were identified in all subjects. Fiber tract maps might have the prospect of guiding neurosurgical interventions, especially when being linked to a neuronavigation system. Other potential applications include the demonstration of the anatomical substrate of functional connectivity in the human brain.

Adult↗
PubMed2001

Dural arteriovenous fistulae at the foramen magnum.

Spinal dural arteriovenous fistulae (DAVF) affect predominantly levels of the lower thoracic and lumbar segments; only 13 cases have been reported of DAVF at the foramen magnum. We present three surgically treated patients with DAVF at the foramen magnum. In none of our three patients could the site of the arteriovenous fistula be suspected from the clinical presentation. The clinical course varied from acutely developing signs and symptoms to a 10-year history of very slowly progressing symptoms. After neuroradiological diagnosis the patients were operated on direct microsurgical disconnection of the arteriovenous shunt via an enlargement of the foramen magnum and a hemilaminectomy of C1. DAVF at the foramen magnum may thus present with slowly to acutely progressing clinical symptoms and signs. Spinal angiographic examination should include the level of the foramen magnum if standard spinal angiography of thoracic, lumbar, and sacral segments is negative in suspected spinal DAVF since the nidus of the shunt can be situated remote from the level of neurological disorder. DAVF at the foramen magnum can be treated very effectively and with minimal surgical trauma by direct microsurgical disconnection of the shunt. This surgical procedure is indicated if embolization with glue is not possible or is unsuccessful.

Central Nervous System Vascular Malformations↗
PubMed2001

Virtual MRI endoscopy: detection of anomalies of the ventricular anatomy and its possible role as a presurgical planning tool for endoscopic third ventriculostomy.

BACKGROUND: Many anatomical anomalies have the potential to impair the efficacy of endoscopic third ventriculostomy (ETV) and increase the surgical morbidity. By virtual magnetic resonance imaging (MRI) endoscopy, the real endoscopic view into the ventricular system can be simulated. It was the objective of the present study to investigate if this simulation is sensitive enough to detect anatomical anomalies of the ventricular system. METHOD: In 18 hydrocephalic patients, first neuronavigationally guided ETV, then virtual MRI endoscopy were performed. This study design allowed for selection of a path for virtual MRI endoscopy, which was identical to that used during surgery, making the real and the virtual view on anatomical structures of the ventricular system highly comparable. It was investigated whether the intra-operatively identified anatomical anomalies could likewise be depicted on virtual MR endoscopic images. FINDINGS: Seven anatomical variants (not enlarged interventricular foramen n=2, atrophic corpus callosum and split fornical bodies n=1, narrow retroclival space n=1, prominent basilar tip n=1, opaque and thick/atypically declining third ventricular floor n=2) were encountered in 5 of the 18 patients during surgery. The five variants of the non-membraneous structures were identified by virtual MRI endoscopy (sensitivity 71%), whereas the anatomical variants of the third ventricular floor were missed. Both the normal as well as the variant third ventricular floor could not be visualised and appeared as a defect. Through this artefact, the anatomy of the major vessels in the interpeduncular cistern could be assessed. INTERPRETATION: The sensitivity of virtual MRI endoscopy for detection of anatomical variants of the ventricular system is low. Its potential usefulness as a presurgical planning tool inspite of this low sensitivity rate is discussed.

Adolescent↗
PubMed2001

Diagnostic and therapeutic management of spinal arachnoid cysts.

BACKGROUND: The wide variety of intraspinal cystic lesions necessitates different elaborate diagnostic procedures to choose the right therapeutic management in symptomatic patients. Based on the case reports of seven patients with symptomatic spinal arachnoid cysts we discuss the aetiology, diagnostic procedures and therapeutic management of extra- and intradural spinal cysts. METHOD: All patients underwent MRI, Myelography and CT-Myelography during diagnostic evaluation. During surgery the cyst was resected and the communication between the cyst and the subarachnoid space was closed. FINDINGS: Two patients were identified with intradural, five with extradural spinal arachnoid cysts. Postoperative outcome was favourable in those patients without preoperative cord damage. INTERPRETATION: MRI is the diagnostic procedure of first choice because of its potential to demonstrate the exact localisation, extent and relationship of the arachnoid cyst to the spinal cord. Cord atrophy secondary to compression can be visualised and used for prediction of neurological outcome. Myelography and CT-Myelography (CTM) are still of diagnostic value since they might demonstrate the communication between the subarachnoid space and the cyst, which is important for surgical planning. The aim of surgical treatment is neural decompression and prevention of refilling of the cyst which is best accomplished by complete resection of the cyst and closure of the communication between cyst and subarachnoid space.

Adult↗
PubMed2001

Influence of intraventricular hemorrhage on outcome after rupture of intracranial aneurysm.

This study was performed to analyze the effect of intraventricular hemorrhage (IVH) on 14-day mortality, outcome at 6 months, and the occurrence of chronic hydrocephalus in patients with aneurysmal subarachnoid hemorrhage. Clinical grade of subarachnoid hemorrhage and the distribution of extravasated blood were evaluated in 219 patients with ruptured aneurysms. Computed tomographic scans performed within 72 h of hemorrhage were analyzed to determine the severity of intraventricular and subarachnoid hemorrhage and the volume of intracerebral hematomas. Outcome at 6 months was assessed using the Glasgow Outcome Scale. Intraventricular hemorrhage extension occurred in 109 of the 219 patients studied. Fourteen-day mortality increased from 7.3% in patients without IVH to 14.1% in those with moderate IVH (IVH score 1-6) and to 41.7% in those with more severe IVH (IVH score > 6). The corresponding figures for unfavorable outcome at 6 months are 19.8%, 30.5%, and 66.7%, respectively. According to logistic regression analyses, the severity of IVH was an independent predictor of mortality and functional outcome. The clinical outcome after aneurysm rupture is at least in part determined by the severity of IVH. Knowledge of the effect of IVH may help guide physicians in the care of patients with aneurysmal bleeding.

Adult↗
PubMed2001

The role of intraoperative magnetic resonance imaging for the detection of hemorrhagic complications during surgery for intracerebral lesions an experimental approach.

BACKGROUND: Intraoperative magnetic resonance imaging (MRI) for guided biopsy or microsurgical resection of intracranial lesions is gaining broader acceptance. It is not known whether intraoperative MRI has the potential to detect hemorrhagic complications of these surgical procedures, because scientific research has so far focussed on the signal characteristics of less acute clots. It is the objective of this experimental study to investigate whether MRI can visualise intracerebral blood within minutes after its occurrence. METHODS: In 26 pigs, a frontal hematoma was produced by injecting autologous blood. Twenty pigs underwent MRI 30 minutes after injection, and 6 pigs within the first 10 minutes. MRI scans were performed on a 1.5T system. T1-weighted spin echo (SE), T2-weighted turbo spin echo (TSE), T2-weighted fluid attenuated inversion recovery (FLAIR), and T2-weighted gradient echo (GE) images were acquired. Depending on the differences of the signal intensities of the hematoma and the surrounding brain, the detectability of the hematoma was rated as good, fair, or poor. RESULTS: None of the induced hematomas were rated to be clearly visible on T1-weighted sequences. Six of the 26 hematomas (23%) were easily detectable on FLAIR sequences, 18 hematomas (69%) on T2-weighted TSE sequences, and 23 hematomas (88%) on the T2-weighted GE sequences. CONCLUSION: Extravasated blood can be identified with a high reliability within minutes after its occurrence on MRI provided that T2-weighted GE sequences are used for imaging. In conclusion, intraoperative MRI is not only of value for guidance of neurosurgical procedures, but also for immediate detection of hemorrhagic complications.

Animals↗
PubMed2001

Navigated transcranial magnetic stimulation for presurgical planning--correlation with functional MRI.

PURPOSE: This paper describes the potential of navigated transcranial magnetic stimulation to map the motor cortex in patients with mass lesions near the primary motor cortex by comparing the results of this technique to those of functional MRI. MATERIAL AND METHODS: Ten patients with mass lesions near the central sulcus were studied preoperatively using a figure-of-eight transcranial magnetic stimulator attached to a neuronavigation system to allow for direct visualization of the stimulated brain region. Subsequently, in all patients a blood oxygenation level dependent 2D multislice multishot T2*-weighted gradient echo EPI sequence on a 1.5 T Philips Gyroscan during motor activation was performed. Results of both methods were coregistered and compared. RESULTS: The distances between the peak parenchymal fMRI activation and the cortical area where TMS elicited the maximum MEPs ranged between 0 and 1.2 cm (mean 0.6 cm, SD 0.4 cm). CONCLUSION: We conclude that navigated TMS is a reliable alternative for localizing the motor-related areas in the human brain preoperatively and therefore may be a useful adjunct or, in selected patients, even a helpful alternative to functional MRI.

Adult↗
PubMed2001

Occurrence and therapy of space-occupying cystic lesions after brain tumor surgery.

OBJECTIVES: Space-occupying cystic lesions may develop in a variable time after resection of particular intracranial tumors, representing a small amount of complications of these procedures. We present our experience with the development and operative treatment of such postoperative cystic lesions in order to identify possible risk factors and to optimize the treatment. METHODS: The records and neuroradiological findings of patients, operated on either gliomas and meningeomas or craniopharyngeomas, who developed symptomatic cystic lesions in the former tumor resection area during the last ten years, were analyzed. RESULTS: 31 patients (2.5%) out of a total of 1240 corresponding tumor operations were identified. The mean age among the 20 female and 11 male patients was 47 years (12-74 years). In 17 patients (55%) the cystic lesion occured within 6 months after tumor resection (mean 5.6 weeks) and in 14 patients (45%) later than 6 months postoperatively (mean 3.6 years). 22 patients (71%) had malignant tumors and 16 patients (52%) had previous radiation therapy. 14 patients (45%) had more than one tumor resection at the same location and one patient had a postoperative meningitis as predisposing factor for the cyst-formation. All patients profited of the various definitive treatment modalities: repetitive percutaneous puncture/external drainage (5 patients), craniotomy for cyst-resection/-fenestration without (5 patients) and with Rickham-catheter implantation (10 patients), endoscopic cyst-fenestration with Rickham-catheter implantation (3 patients) and implantation of cysto-atrial or cysto-peritoneal shunts (8 patients). CONCLUSIONS: Symptomatic cystic lesions developing after brain tumor resection may occur as early - (5.6 weeks) or as late - (3.6 years) complications and though predisposing factors, like malignant primary tumor, preceding radiation therapy and multiple tumor resections can be identified, the reason for their occurrence remains unclear. A variety of effective therapy options is applicable but should consider the patients condition and prognosis.

Astrocytoma↗
PubMed2001

[Background and first results about methodological characteristics of the Aachen Life Quality Inventory].

Health-related quality of life has become an important criterion for assessing disease impact and treatment outcome. Therefore, we developed a questionnaire called Aachen Life Quality Inventory (ALQI) for the use in neurosurgical patients with brain damage. The ALQI is derived from the German version of the Sickness Impact Profile (SIP). The 117 items are formulated on a concrete behavioral level covering the following dimensions of health-related quality of life: 1. activation; 2. mobility; 3. house-work; 4. social contact; 5. family relations; 6. ambulation; 7. work; 8. free-time activities; 9. autonomy; 10. communication; 11. cognitive capacity. As in the SIP, a summary score of total impairment (ALQI Total score), a summary score covering the psycho-social dimension (ALQI Psycho-social score) and a summary score covering aspects of physical functioning (ALQI Physical score) can be calculated. The ALQI consists of a self-rating and a parallel proxy-rating version. The ALQI was validated and psychometrically verified using the data of as yet 231 neurosurgical patients with brain damage of mixed etiology (subarachnoid hemorrhage, closed-head injury, benign brain tumors). Internal consistency (Cronbach's Alpha) ranged from.68 to.91 for the subscales, while it was.97 for the whole instrument,.94 for the psycho-social and.93 for the physical score. The internal consistency for the subscales of the proxy-rating version of the ALQI ranged between.77 and.92, while it was.97 for the whole inventory and.94 for the psycho-social and the physical scores, respectively. Examination of construct validity revealed substantial correlations with a wide range of relevant neurological, neurosurgical and neuropsychological parameters. Beyond other findings, substantial associations emerged with several neuropsychological tests (r =.30 to r =.50), the Glasgow Outcome Scale (r =.39; p <.00) and in patients after subarachnoid hemorrhage with the Hunt& Hess grading (r =.28; p <.001). According to these results, the ALQI promises to become a valid and reliable means for assessing quality of life in patients with brain damage. Nevertheless, further analyses using larger patient samples and with particular emphasis on the investigation of the retest-reliability and the prognostic validity are called for in the future.

Attitude to Health↗
PubMed2001

Three-dimensional visualization of the pyramidal tract in a neuronavigation system during brain tumor surgery: first experiences and technical note.

OBJECTIVE: To integrate spatial three-dimensional information concerning the pyramidal tracts into a customized system for frameless neuronavigation during brain tumor surgery. METHODS: Four consecutive patients with intracranial tumors in eloquent areas underwent diffusion-weighted and anatomic magnetic resonance imaging studies within 48 hours before surgery. Diffusion-weighted datasets were merged with anatomic data for navigation purposes. The pyramidal tracts were segmented and reconstructed for three-dimensional visualization. The reconstruction results, together with the fused-image dataset, were available during surgery in the environment of a customized neuronavigation system. RESULTS: In all four patients, the combination of reconstructed data and fused images was a helpful additional source of information concerning the tumor seat and topographical interaction with the pyramidal tract. In two patients, intraoperative motor cortex stimulation verified the tumor seat with regard to the precentral gyrus. CONCLUSION: Diffusion-weighted magnetic resonance imaging allows individual estimation of large fiber tracts applicable as important information in intraoperative neuronavigation and in planning brain tumor resection. A three-dimensional representation of fibers associated with the pyramidal tract during brain tumor surgery is feasible with the presented technique and is a helpful adjunct for the neurosurgeon. The main drawbacks include the length of time required for the segmentation procedure, the lack of direct intraoperative control of the pyramidal tract position, and brain shift. However, mapping of large fiber tracts and its intraoperative use for neuronavigation have the potential to increase the safety of neurosurgical procedures and to reduce surgical morbidity.

Aged↗
PubMed2001

Intravascular ultrasound Doppler measurement of blood flow velocity.

BACKGROUND AND PURPOSE: The authors investigated the feasibility and accuracy of intravascular Doppler sonography (IVDS) with a newly developed microprobe. METHODS: The known method to determine blood flow velocity by transcutaneous Doppler sonography was transferred to an intravascular usable Doppler probe. With the improved technique, a microprobe measuring 0.3 mm in diameter can be advanced through a 5F catheter used in routine diagnostic angiography to perform intravascular Doppler sonography. In a first step, the conditions for application and measurement were studied in a flow tube model and were transferred in a second step to patients undergoing routine angiography and patients with arterial stenoses. RESULTS: Measurements with nondegassed liquids showed a high intensive acoustic signal, but no echo effect could be recorded in degassed liquids. IVDS of healthy vessels in 40 patients showed the same typical flow pulse curve as seen in transcutaneous measurements. The optimal position of the microprobe with respect to the contact of the vessel wall, the diastolic and systolic phase, and the distance to the tip of the catheter could be evaluated. In 95.6% of the 40 patients with healthy vessels, IVDS was successful. Fourteen patients with arterial stenotic diseases were investigated before and after percutaneous transluminal angioplasty, and the results of these investigations correlated well with the angiographical results. CONCLUSIONS: For percutaneously directly reachable vessels, the transcutaneous Doppler sonography is the choice for easy noninvasive and inexpensive measurement of blood flow velocity. However, for vessels that are difficult or impossible to reach percutaneously, intravascular measurement is a valid procedure.

Angiography↗
PubMed2001

Functional MRI for presurgical planning: problems, artefacts, and solution strategies.

OBJECTIVES: Presurgical mapping of motor function is a widely used clinical application of functional (f) MRI, employing the blood oxygenation level dependent contrast. The aim of this study was to report on 3 years experience of 194 fMRI studies on the representation of motor function in 103 patients and to describe the problems and artefacts that were typically present. METHODS: An evaluation was carried out to determine whether the patients' age, type or location of the tumourous lesion, severity of the paresis, or the tasks used during the investigation have an effect on artefacts of fMRI studies and how these artefacts are best overcome. RESULTS: Functional MRI identified the motor regions in 85% of all investigated paradigms. In 11% of the investigated patients no information at all on functional localisation was obtained. A draining vein within the central sulcus was present in all patients that showed activation within the parenchyma of the precentral gyrus but also in three patients in whom no parenchymal activation was present. Head movement artefacts were the most frequent cause for fMRI failure, followed by low signal to noise ratio. Motion artefacts were correlated with the degree of paresis and with the functional task. Tasks involving more proximal muscles led to significantly more motion artefacts when compared with tasks that primarily involved distal muscles. Mean MR signal change during task performance was 2.5%. CONCLUSIONS: Most of the artefacts of functional MRI can be reliably detected and at least in part be reduced or eliminated with the help of mathematical algorithms, appropriate pulse sequences and tasks, and-probably most important-by evaluating the fMRI raw data-that is, the MR signal time courses.

Adolescent↗
PubMed2001

Metabolic and electrophysiological validation of functional MRI.

OBJECTIVES: Although functional MRI is widely used for preoperative planning and intraoperative neuronavigation, its accuracy to depict the site of neuronal activity is not exactly known. Experience with methods that may validate fMRI data and the results obtained when coregistering fMRI with different preoperative and intraoperative mapping modalities including metabolically based (18)F-fluorodeoxyglucose PET, electrophysiologcally based transcranial magnetic stimulation (TMS), and direct electrical cortical stimulation (DECS) are described. METHODS: Fifty patients were included. PET was performed in 30, TMS in 10, and DECS in 41 patients. After coregistration using a frameless stereotactic system, results were grouped into overlapping (<1 cm distance), neighbouring (<2 cm), or contradictory (>2 cm). RESULTS: Comparing fMRI with PET, 18 overlapping, seven neighbouring, and one contradictory result were obtained. In four patients no comparison was possible (because of motion artefacts, low signal to noise ratio, and unusual high tumour metabolism in PET). The comparison of TMS and fMRI showed seven overlapping and three neighbouring results. In three patients no DECS results could be obtained. Of the remaining 38 patients, fMRI hand motor tasks were compared with DECS results of the upper limb muscles in 36 patients, and fMRI foot motor tasks were compared with DECS results of the lower limb on 13 occasions. Of those 49 studies, overlapping results were obtained in 31 patients, and neighbouring in 14. On four occasions fMRI did not show functional information (because of motion artefacts and low signal to noise). CONCLUSIONS: All validation techniques have intrinsic limitations that restrict their spatial resolution. However, of 50 investigated patients, there was only one in whom results contradictory to fMRI were obtained. Although it is not thought that fMRI can replace the intraoperatively updated functional information (DECS), it is concluded that fMRI is an important adjunct in the preoperative assessment of patients with tumours in the vicinity of the central region.

Adult↗