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Biomedical subjects

J M Gilsbach

Publications and source records attributed to J M Gilsbach.

At least 37 records · Page 2Linked to original sources
PubMed2003

[Aneurysmal subarachnoid hemorrhage: role of computerized tomography for correct prediction of the ruptured aneurysm site].

OBJECTIVE: To investigate if the intracisternal distribution of subarachnoid hemorrhage (SAH) following aneurysm rupture allows the correct prediction of the symptomatic aneurysm site. [nl] METHODS: Ninety-nine consecutive patients with acute SAH and angiographically proven aneurysm were included into the study. The parent vessel of the diagnosed aneurysms were the anterior communicating artery (ACoA) in 38 patients, the middle cerebral artery (MCA) in 26 patients, the internal carotid artery (ICA) in 25 patients, the pericallosal artery (A2) in 5 patients, the basilar artery (BA) in 4 patients and the vertebral artery (VA) in 1 patient. In 21 patients, an additional asymptomatic aneurysm was diagnosed. The initial computerized tomography (CT) scans of the 99 patients were given to 2 experienced vascular neurosurgeons, who were blinded for the angiography findings. The 2 investigators had to predict the site of the ruptured aneurysm. [nl] RESULTS: Investigator 1 correctly predicted the aneurysm site in 56 (57 %), investigator 2 in 59 of the 99 patients (60 %). Investigator 1 correctly identified 81 % of the MCA aneurysms, and investigator 2 74 % of the ACoA aneurysms. However, in only 46 of the 99 patients (47 %), the aneurysm site was correctly predicted by both investigators together. [nl] CONCLUSION: The results indicate, that the distribution of the subarachnoid blood as shown on the first CT scan after aneurysm rupture barely allows to predict the symptomatic aneurysm site. Thus, neurosurgical decision making (identification of the ruptured aneurysm in patients with multiple aneurysms; surgical exploration in patients with non-perimesencephal SAH, but negative angiography) should not rely on the first CT scan after SAH.

Adult↗
PubMed2003

[Diffusion Weighted Imaging Combined with Intraoperative 3D-Ultrasound and fMRI for the Resection of an Optic Radiation Cavernoma].

A 17-year-old patient with a symptomatic cavernoma of the optic radiation underwent surgery supported by functional magnetic resonance imaging (fMRI), diffusion weighted magnetic resonance imaging (DWI) and navigated 3D-ultrasound. The primary visual cortex was visualized with fMRI. The optic radiation was delineated by means of DWI. The diffusion weigthed images were used for 3-dimensional reconstruction of the optic radiation. During surgery, the information of the localisation of functional brain regions were used together with the 3D-ultrasound, enabling the surgeon to remove the cavernoma without morbidity. This is the first report of the combined use of fMRI, fiber tract imaging and 3D-ultrasound for the safe resection of an optic radiation lesion.

Adolescent↗
PubMed2003

Microsurgical therapy of symptomatic lumbar juxta facet cysts.

OBJECTIVE: Symptomatic lumbar juxta facet cysts (ganglion and synovial cysts) (JFC) are uncommon lesions of the spine, causing radiculopathy and low back pain. The authors present their experiences with microsurgically treated JFC. This rare pathology is discussed with special focus on therapeutic concepts and long-term outcome. METHOD: The records of 27 patients with symptomatic lumbar JFC were retrospectively reviewed. The clinical data and diagnostic procedures were evaluated. The patient age ranged from 38 to 83 years (mean 61 years). Treatment consisted exclusively of microsurgical excision of the cysts after partial hemilaminectomy. The early surgical results were evaluated 6 weeks after surgery. For assessment of late surgical results (mean follow-up period 70 months), the Finneson and Cooper outcome scale was used. RESULTS: After 6 weeks, the preoperative symptoms were improved in 25 patients (93 %). Long-time follow-up was available in 23 patients. Good (pain improved and able to function well) to excellent (pain free and able to function well) results were still found in 83 % of the patients. With exception of 2 small asymptomatic dural tears and a slight temporary increase of the preoperative paresis, no surgical complications were encountered. One JFC recurred after 4 months and required re-operation with finally good outcome. CONCLUSION: Adequate and definitive treatment in symptomatic JFC consists in microsurgical resection. A partial hemilaminectomy is sufficient for surgical exposure. Excellent long-term outcome can be achieved. Recurrences and surgical complications are rare.

Adult↗
PubMed2003

Recurrent intracranial sarcoma mimicking chronic subdural haematoma.

Primary sarcomas of the central nervous system and their coincidence with a subdural haematoma are each rare. We describe an unusual case of unsuspected dural spreading of a recurrent spindle cell sarcoma concealed in a chronic subdural haematoma, which occurred months after microsurgical resection and external radiation of a temporal parenchymatous sarcoma.

Brain Neoplasms↗
PubMed2003

Measurement of motor evoked potentials following repetitive magnetic motor cortex stimulation during isoflurane or propofol anaesthesia.

BACKGROUND: Isoflurane and propofol reduce the recordability of compound muscle action potentials (CMAP) following single transcranial magnetic stimulation of the motor cortex (sTCMS). Repetition of the magnetic stimulus (repetitive transcranial magnetic stimulation, rTCMS) might allow the inhibition caused by anaesthesia with isoflurane or propofol to be overcome. METHODS: We applied rTCMS (four stimuli; inter-stimulus intervals of 3, 4, 5 ms (333, 250, 200 Hz), output 2.5 Tesla) in 27 patients and recorded CMAP from the hypothenar and anterior tibial muscle. Anaesthesia was maintained with fentanyl 0.5-1 microg kg(-1) x h(-1) and either isoflurane 1.2% (10 patients) or propofol 5 mg kg(-1) x h(-1) with nitrous oxide 60% in oxygen (17 patients). RESULTS: No CMAP were detected during isoflurane anaesthesia. During propofol anaesthesia 333 Hz, four-pulse magnetic stimulation evoked CMAP in the hypothenar muscle in 75%, and in the anterior tibial muscle in 65% of the patients. Less response was obtained with 250 and 200 Hz stimulation. CONCLUSIONS: In most patients, rTCMS can overcome suppression of CMAP during propofol/nitrous oxide anaesthesia, but not during isoflurane anaesthesia. A train of four magnetic stimuli at a frequency of 333 Hz is most effective in evoking potentials from the upper and lower limb muscles. The authors conclude that rTCMS can be used for evaluation of the descending motor pathways during anaesthesia.

Adult↗
PubMed2003

Pituitary deficiency following aneurysmal subarachnoid haemorrhage.

OBJECTIVE: To investigate the incidence and severity of pituitary insufficiency after aneurysmal subarachnoid haemorrhage. METHODS: Pituitary function was tested in a series of patients more than 12 months but less than 60 months after aneurysmal subarachnoid haemorrhage using a combined TRH-LHRH-arginine test and the insulin tolerance test, to elucidate possible deficits in the gonadotrophic, somatotrophic, thyreotrophic, and corticotrophic hormonal axes. RESULTS: Of 21 patients screened, nine (43%) showed deficiencies of at least one pituitary hormone axis. Four patients had corticotrophin deficiency, one had partial growth hormone deficiency, two had severe growth hormone deficiency, and two had severe growth hormone deficiency plus corticotrophin deficiency. CONCLUSIONS: Persistent pituitary dysfunction may be more common after aneurysmal subarachnoid haemorrhage than has so far been recognised and warrants further investigation, given the possibility that some health and neurobehavioural problems in these patients could result from hormone deficiency.

Adrenocorticotropic Hormone↗
PubMed2003

Focused high frequency repetitive transcranial magnetic stimulation for localisation of the unexposed primary motor cortex during brain tumour surgery.

OBJECTIVES: To investigate if intraoperative focused high frequency repetitive transcranial magnetic stimulation (rTMS) can localise the primary motor cortex without exposure of the cortical surface. METHODS: A high frequency train (357 Hz) of four suprathreshold magnetic stimuli was delivered transcranially to the region of the rolandic area during brain tumour operations in 12 patients. To induce a focal magnetoelectric field, the flat figure of eight coil (outer diameter of each loop 7 cm) was used. Motor evoked potentials (MEP) were recorded in eight muscles of the upper and lower contralateral extremities. The first stimulation site was 2.5 cm behind the bregma, the second site 2 cm, and the third site 4 cm dorsal to the first stimulation site. If no MEP were obtainable, stimulation was repeated in anteroposterior direction at more laterally located sites. Using neuronavigation, each positive stimulation site was correlated with the underlying cortical anatomy. RESULTS: Stimulation was performed at a total of 42 sites (in two patients, maximum stimulation at the three initial sites failed to evoke a motor response). In four patients, MEP were obtained only from one stimulation site. This site exactly overlayed the primary motor cortex. In eight patients, MEP could be elicited from more than one stimulation site. In seven of the eight patients, the site from which MEP with peak amplitudes were elicited, corresponded to the primary motor cortex. In total, the primary motor cortex was correctly identified on the basis of electrophysiological findings in 11 of 12 patients (92 %). In two patients, only the more lateral stimulation sites permitted MEP recording. CONCLUSION: Intraoperative focused rTMS is highly sensitive for localisation of the primary motor cortex. Focused rTMS as a localising instrument alleviates the need of motor cortex exposure and, thereby, can contribute to minimise the surgical approach to brain tumours in the rolandic area.

Adult↗
PubMed2002

Endovascular treatment of experimental aneurysms in rabbits using Guglielmi detachable coils -- a feasibility study.

The Guglielmi detachable coil (GDC) has been generally accepted for treatment of intracranial aneurysms. Preclinical testing of new coil developments requires animal models of aneurysms which imitate human aneurysms in size, configuration and neck morphology. We assessed in detail the technical requirements and steps for transfemoral treatment of experimentally induced aneurysms at the top of the brachiocephalic trunk (TBC) in rabbits. We created aneurysms in five rabbits by distal ligation and intraluminal incubation of the right common carotid artery with elastase. All animals were treated successfully 2-3 weeks after induction of the aneurysm, with dense packing of the coils. No complications related to the procedures occurred. The study demonstrates that our animal model can be a suitable method for testing the biocompatibility and occlusion rate of new embolic materials.

Aneurysm↗
PubMed2002

Factors related to the magnitude of T2* MR signal changes during functional imaging.

Our aim was to determine whether age, sex, the degree of weakness, anticonvulsants, the histology of the underlying lesion(s), the presence of oedema or the distance of the lesion from the motor region have an impact on the blood oxygenation level-dependent (BOLD) signal strength and therefore on the validity of functional MRI (fMRI). We studied 98 patients with masses near the central region imaged for surgical planning at 1.5 tesla, employing a BOLD sequence during a motor task. We calculated percentage signal change in the primary motor cortex between rest and activation and carried out multiple linear regression to examine the impact of the above factors on signal strength. Using a stepwise analysis strategy, the distance of the lesion from the motor region had the strongest influence (r=0.653, P<0.001). The factor with largest uncorrelated additional impact on signal change was the presence of oedema. Both predictors together formed a highly significant multiple r=0.739 ( P<0.001). No other predictive factor was identified (all P>0.20). Disturbances of cerebral blood flow and metabolism induced by the tumour were presumed to be the causes of a decrease in signal in the adjacent cortex.

Adolescent↗
PubMed2002

Activation in primary and secondary motor areas in patients with CNS neoplasms and weakness.

OBJECTIVE: To demonstrate whether cortical activation within different cortical motor regions in neurosurgical patients varies with the degree of paresis induced by mass lesions near the central region. METHODS: A total of 110 patients with brain tumors infiltrating the central region and with varying degrees of paresis were investigated employing fMRI during the performance of hand motor tasks. The percent signal change between rest and activation was calculated for four cortical regions: primary motor cortex (M1), supplementary motor area, premotor area, and superior parietal lobule. RESULTS: Significant decreases in activation with increasing degrees of paresis were found in M1, whereas significant increases in activation were noted in secondary motor areas that were not affected by the tumor. CONCLUSIONS: The signal loss in areas adjacent to tumor tissue may relate either to tumor-induced changes in cerebral hemodynamics or to a direct loss of cortical neurons resulting in a lesser degree of hemodynamic changes after motor activation. The increase in activation within secondary motor areas with increasing degrees of paresis supports the growing evidence of a practice- and lesion-dependent reorganization of the cortical motor system and the ability of the brain to modulate its excitatory output according to external demands.

Adult↗
PubMed2002

[Treatment options in traumatic epidural hematomas].

The authors report 118 consecutive cases of patients with traumatic extradural hematoma (EDH) which were analyzed according to different clinical parameters and treatment modalities. Patients, treated for EDH between 1992 and 1998 in our department were distributed into 5 treatment groups depending on their clinical and neuroradiological findings on admission and during the hospitalization. Group I consisted of 75 patients (64%) who required immediate surgical evacuation of the hematoma after admission. Group II included 12 patients (10%) with initially conservative treatment despite visible EDH on the first CT-scan, which had to be operated on in the course because of neurological deterioration or increase of hematoma size. The 14 patients (12%) forming group III developed an acute EDH after the initial CT-scan revealed no extradural blood; 7 patients (6%) out of group IV showed a chronic EDH (delay trauma/diagnosis > 72 h), which required operative evacuation. All 10 patients (8%) comprising group V were treated conservatively. In each group the following parameters were analyzed: patient age, size and location of hematoma, trauma mechanism, additional intracranial lesions or skull fractures, intraoperative findings and neurostatus on admittance and during the hospitalization. The decision for non-operative treatment of EDH and the timing of a delayed intervention has to be made individually in each case in dependence of parameters like patient age, hematoma-size and -location and neurological status and course. Chronic EDH should be operated immediately, as well as hematomas presenting with an increase in size. Delayed developing EDH imply worse outcome and make adequate surveillance of high-risk patients mandatory.

Adolescent↗
PubMed2002

[Pterional orbital decompression in traumatic orbital hematomas].

The results are presented for pterional orbital decompression in 12 patients with symptomatic traumatic retrobulbar hematoma after various traumatic mechanisms. Pre- and postoperative course, neuroradiological findings, additional brain or facial injuries as well as outcome of eye function are analyzed in detail. Mean time delay between trauma and decompression was 56 h (2.4 days), with a wide range from 2 h to 15 days. Preoperative exophthalmos and pupillary disturbances as well as restrictions of extraocular movements decreased in all patients after orbital decompression and removal of the retrobulbar hematoma if the bleeding was localized. Visual acuity remained normal or showed significant improvement in seven patients, four of whom experienced complete recovery. In three patients the eye remained amaurotic. No complications related to the operation were seen. The pterional orbital decompression described here represents an effective alternative approach for patients with sight-threatening retrobulbar hematoma, especially in cases where it is necessary to gain space for the orbit in addition to evacuating space-occupying blood or bone clots and treating neighbouring lesions. Immediate detection and adequate treatment of orbital hematomas is mandatory to achieve an acceptable outcome of eye function.

Adolescent↗
PubMed2002

Incidence of cerebrospinal fluid leak after microsurgical removal of vestibular schwannomas.

OBJECTIVES: Cerebrospinal fluid (CSF) leak still remains an unresolved problem after microsurgical removal of vestibular schwannomas (VS). METHODS: 14 (6%) Cases of cerebrospinal fluid rhinorrhea and 3 cases with subcutaneous retro-auricular CSF collection, occurring in a series of 224 patients operated on by the senior author (JMG) on VS between 1989-2000 via the suboccipital retrosigmoidal approach were studied retrospectively. Prophylaxis of CSF leak was usually attempted by packing the unroofed posterior wall of internal acoustic meatus with muscle. The mastoid air cells were packed first with collagen then with muscle and bone dust. RESULTS: All CSF leaks were diagnosed within 2-7 days after surgery. We found no relation to tumour size. Treatment was initiated in all patients with continuous external lumbar cerebrospinal fluid drainage (CELCFD) for 7 days. In 11 cases with CSF rhinorrhea and all cases with retro-auricular CSF collection, the CSF leak was stopped. However, in 3 cases the CSF leak persisted despite the lumbar drain. These patients were operated on again with sealing the IAM and the mastoid cells again with muscle and collagen. No recurrence of CSF leak was noted after the second operation. There was no case of late onset CSF leak during the follow-up of one year. CONCLUSION: Although CSF leak is a common complication (6%) after vestibular schwannoma removal, aggressive treatment is required only in a few cases (1%). Most of the cases are successfully treated by (CELCFD). The suboccipital approach offers an advantage of opening only a part of mastoid air cells, which are in our opinion the second most common site of CSF leakage.

Bone Transplantation↗
PubMed2002

Functional MRI and 18F FDG-positron emission tomography for presurgical planning: comparison with electrical cortical stimulation.

BACKGROUND: In patients with mass lesions near "eloquent" cortical areas different preoperative mapping techniques can be used. Two of the most widely used approaches include positron emission tomography (PET) and functional MRI (fMRI). We employed both methods in the same patients undergoing presurgical evaluation and compared the results to those obtained by direct electrical cortical stimulation (DECS). METHOD: 22 patients with tumours of different aetiology near the central region were investigated. FMRI was performed using a T2(*)-weighted gradient-echo BOLD sequence at 1.5 T, PET was performed after injection of 122-301 MBq (18)F-Fluorodeoxyglucose (18-FDG) under rest and activation conditions. DECS was performed in all patients with recordings of muscles primarily involved in the investigated tasks. FINDINGS: In 19 patients all three modalities could be compared, 1 patient demonstrated discordance between fMRI and PET with DECS speaking in favour of fMRI, 6 patients had neighbouring results of PET and fMRI (between 1-2 cm distance), 12 patients had overlapping results. INTERPRETATION: The high incidence of neighbouring results is presumably related to fMRI specific artefacts. Advantages of fMRI are: Higher spatial and temporal resolution, more and different functional runs, shorter examination time, wider availability, longitudinal examinations, non-invasiveness and cost-effectiveness, easy registration to anatomical images. Advantages of PET are: higher signal-to-noise ratio, lesser susceptibility to artefacts (motion, draining veins), evaluation of tumour metabolism. It is our opinion that the neurosurgeon has to decide on a case-by-case basis which study suits his specific needs in the presurgical evaluation of his patient.

Adult↗
PubMed2002

Follow-up of extended pterional orbital decompression in severe Graves' ophthalmopathy.

BACKGROUND: Compressive optic neuropathy (CON) with visual loss is, apart from corneal exposure and disfigurating proptosis, the most serious clinical sign encountered in Graves' ophthalmopathy. However, numerous different approaches and operative techniques have been proposed for orbital decompression, with varying results and side effects. The purpose of the present study was to analyze peri-operative data and long-term results in patients with severe thyroid-related orbitopathy, treated by extended pterional orbital decompression, comparing its effectiveness to other procedures. METHOD: An extended pterional orbital decompression was performed in 42 consecutive patients (59 orbits) with severe thyroid-associated ophthalmopathy after failure of medical and radiation therapy during an 11-year period. Pre- and postoperative examination included visual acuity, Hertel exophthalmometry, ocular motility, visual fields (Goldmann perimetry) and notification of complications. Long-term evaluation was carried out on average at 11 months postoperatively (range 5-26 months). FINDINGS: Visual acuity improved rapidly from a preoperative average of 0.53 +/- 0.33 (range, 0-1) to 0.77 +/- 0.31 (range, 0-1) postoperatively (p<0.001). Worsening was not seen. An average reduction of proptosis of 3.79 +/- 2.32 mm (range, 0.5-8 mm) was achieved with a mean preoperative Hertel measurement of 24.7 +/- 3.93 mm (range, 15-33 mm) (p<0.001). Double vision and restriction of eye motility was present in 76.3% of patients preoperatively and improved in 63% of patients (p<0.001). No new onsets of not already pre-existing double vision was seen. Complications included two cases of permanent palsy of the frontal branch of the facial nerve. INTERPRETATION: The extended pterional orbital decompression improved vision and decreased proptosis and restriction of extra-ocular movements in patients with severe sight-threatening and disfiguring cases of Graves' orbitopathy and is still an effective and low-risk alternative to other non-neurosurgical operative techniques. Especially new developing postdecompression strabismus can be successfully avoided.

Adult↗
PubMed2002

Movement artefacts and MR BOLD signal increase during different paradigms for mapping the sensorimotor cortex.

BACKGROUND: The authors evaluated the impact of motion artefacts on presurgical mapping of the sensorimotor cortex with functional magnetic resonance imaging (fMRI). Different mapping paradigms were compared with regard to the frequency of motion artefacts and the resulting signal increase. METHOD: 94 surgical candidates with mass lesions near the central region were investigated using BOLD(1)-contrast T2(*) weighted multislice multi-echo EPI gradient echo sequences on a 1,5 T Philips Gyroscan. Three functional paradigms were performed: a) repetitive self-paced clenching of the hand to a fist (68 runs); b) repetitive finger-to-thumb opposition (46 runs); c) sensory stimulation by repetitive brushing of the palm (15 runs). Task-related haemodynamic changes were identified by statistical analysis with the Kolmogorov-Smirnov-test. MR signal increase in percent was calculated for each of the paradigms. Motion artefacts were rated on a scale from 1 to 3. FINDINGS: Severe motion artefacts occurred in 8 hand clenching runs and in 2 finger opposition runs. Artefacts were more pronounced in hand clenching than in finger opposition. There were no motion artefacts in any of the sensory stimulation runs. Concerning the percent MR signal change there was no significant difference between hand clenching and finger opposition (T-test: p>0,5) but a highly significant difference (p<0,0001) between both motor tasks and the sensory paradigm (hand clenching: 2.68+/-0.75; finger opposition: 2.76+/-0.79; sensory stimulation: 1.72+/-0.65). INTERPRETATION: Sensory stimulation causes by far less artefacts than motor paradigms but it also has to be considered less sensitive as it produces a smaller MR signal increase. Therefore in presurgical evaluation sensory stimulation should be kept in reserve for cases in whom motion artefacts are very likely to occur, i.e. patients with severe forms of paresis.

Adolescent↗
PubMed2002

Error analysis in cranial neuronavigation.

Neuronavigation systems are now an important component of many modern neurosurgical treatment strategies. Their support facilities intraoperative orientation and makes neurosurgical operations more precise and less traumatic. Computer-aided neurosurgery is definitively not a temporary fashionable phenomenon, the concept of neuronavigation is here to stay. This report summarizes a ten-years-long experience and presents an error analysis of 108 failures (12.4 %) in a total of 874 image-guided cranial neurosurgical procedures with an arm-linked (mechanical) system and two different infrared-light emitting (optical) systems. The application of neuronavigation incurs multiple reasons for pitfalls because of the complex man-machine interface. Principally, we have to differentiate two types of errors: "machine made errors" due to soft- or hardware failure and "man made errors" generally, due to inadequate handling of the navigation system. The error analysis demonstrated that the so-called human interface plays the main role causing a high error rate.

Bias↗