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Biomedical subjects

J Gilsbach

Publications and source records attributed to J Gilsbach.

At least 19 recordsLinked to original sources
PubMed2001

Localisation of motor areas in brain tumour patients: a comparison of preoperative [18F]FDG-PET and intraoperative cortical electrostimulation.

Assessment of the exact spatial relation between tumour and adjacent functionally relevant brain areas is a primary tool in the presurgical planning in brain tumour patients. The purpose of this study was to compare a preoperative fluorine-18 fluorodeoxyglucose positron emission tomography ([18F]FDG PET) activation protocol in patients with tumours near the central area with the results of intraoperative direct cortical electrostimulation, and to determine whether non-invasive preoperative PET imaging can provide results equivalent to those achieved with the invasive neurosurgical "gold standard". In this prospective study, we examined 20 patients with various tumours of the central area, performing two PET scans (each 30 min after i.v. injection of 134-341 MBq [18F]FDG) in each patient: (1) a resting baseline scan and (2) an activation scan using a standardised motor task (finger tapping, foot stretching). Following PET/MRI realignment and normalisation to the whole brain counts, parametric images of the activation versus the rest study were calculated and pixels above categorical threshold values were projected to the individual MRI for bimodal assessment of morphology and function (PET/MRI overlay). Intraoperative direct cortical electrostimulation was performed using a Viking IV probe (5 pulses, each of 100 micros) and documented using a dedicated neuro navigation system. Results were compared with the preoperative PET findings. PET revealed significant activation of the contralateral primary motor cortex in 95% (19/20) of the brain tumour patients (hand activation 13/13, foot activation 6/7), showing a mean increase in normalised [18F]FDG uptake of 20.5% +/- 5.2% (hand activation task) and 17.2% +/- 2.5% (foot activation task). Additionally detected activation of the ipsilateral primary motor cortex was interpreted as a metabolic indication for interhemispheric compensational processes. Evaluation of the PET findings by cortical stimulation yielded a 94% sensitivity and a 95% specificity for identification of motor-associated brain areas. In conclusion, the findings indicate that a relatively simple and clinically available [18F]FDG PET activation protocol enables a sufficiently precise assessment of the local relation between the intracranial tumour and the adjacent motor cortex areas and may facilitate the presurgical planning of tumour resection.

Adult↗
PubMed2000

Virtual placement of frontal ventricular catheters using frameless neuronavigation: an "unbloody training" for young neurosurgeons.

OBJECTIVE: To evaluate virtually the reliability of freehand puncture of the anterior horn of the lateral ventricle and to provide realistic, but unbloody training for young neurosurgeons. METHODS: Virtual placement of ventricular catheters was performed repeatedly by neurosurgical doctors and thereafter controlled by neuronavigation. With the help of a frameless stereotactic navigation device they virtually had to hit the anterior horn of the lateral ventricle on the MRI of 29 brains with normal ventricular sizes and 60 pathological ventricles, respectively. The catheter placement was simulated using the pointer of the navigation system (EasyGuide Neuro). The monitor screen was blinded, so that on-line control was impossible. Virtual elongation of the pointer tip was performed on the workstation and the position of the virtual catheter was evaluated on a printout. RESULTS: Virtual freehand catheter placement was performed 145 times into the MRIs of the normal brains. In 66 cases (45%) the site of the catheter tip was judged as accurate as shown by the navigation system. No difference concerning the number of correctly placed catheters was observed when comparing more and less experienced doctors. The results in the 60 pathological MRIs of patients differed with respect to the size of the ventricles: in narrow ventricles an accurate placement succeeded in 7 of 22 cases (32%), moderately enlarged ventricles were accurately hit in 15 out of 32 cases (46%) and wide ventricles in 5 of 6 attempts (83%), respectively. CONCLUSION: This setup is a simple, practicable tool for neurosurgical education. The virtual freehand placement of ventricular drains controlled by neuronavigation provides an unbloody training of a routine neurosurgical procedure in a realistic setting without the risk of injuring a patient. Neuronavigation systems can serve therefore as a link between learning from observation and handling the real situation.

Adolescent↗
PubMed1999

Preoperative PET activation for assessment of motor cortex area in precentral chondroma.

BACKGROUND: A main problem in the preoperative planning for precentral tumors is the exact assessment of the spatial relationship between the tumor and the functionally relevant brain areas, which may be difficult using only morphologically oriented imaging (CT, MRI). Therefore, we applied motor activation PET and PET/MRI overlay in a patient with a precentral tumor. DESCRIPTION: We report the case of a 21-year-old woman suffering from progressive right-sided headache and intermittent dysesthesia of the left leg. MRI showed a hypointense tumor with inhomogenous contrast enhancement in the right precentral area. For preoperative assessment of the spatial relationship between the tumor and the motor cortex area, the patient underwent two F-18-fluorodeoxyglucose positron emission tomography (PET) scans (1. resting condition and 2. motor activation of the left leg) and subsequent calculation of subtraction images of activation minus rest. Fusion of PET and MRI data (PET/MRI overlay) was performed for bimodal function and morphology presentation. PET revealed an activation pattern behind and below the tumor, indicating that the motor cortex area was shifted to the back. PET findings were confirmed by intraoperative electrophysiology. Cortical stimulation combined with intraoperative neuronavigation localized the motor area of the left foot and leg exactly at the dorsal border, below and lateral to the lesion. After complete resection of the solid tumor, histopathological examination revealed a chondroma. The postoperative course was uneventful, and the patient was discharged without neurological deficits. CONCLUSIONS: This case shows that biomodal imaging (PET/MRI) provides a noninvasive exact assessment of functionally important cortex areas for preoperative planning in patients with cerebral lesions.

Adult↗
PubMed1998

Microsurgical treatment of midfacial tumours involving the skull base.

Various approaches to the base of the skull for the treatment of cranial base tumours are described in detail. Advantages and disadvantages of the particular approaches are discussed. This clinical experience is based on 303 neoplasms involving the base of the skull, operated on by the authors. Retrospective survival studies are presented and a review of the literature on the subject is discussed. Utilizing microsurgical techniques the 2-, 3- and 5-year survival rates were significantly improved. The functional and aesthetic outcomes were also dramatically superior compared with standard ablative procedures. Reconstructive postoperative strategies are suggested.

Carcinoma, Adenoid Cystic↗
PubMed1996

Deafness due to bilateral endolymphatic sac tumours in a case of von Hippel-Lindau syndrome.

A case of bilateral endolymphatic sac tumours is reported. In a patient with von Hippel-Lindau syndrome, tumour growth in the right cerebellopontine angle caused deafness. The tumour was removed and classified as a metastasis from a thyroid carcinoma. However, on thyroidectomy no primary neoplasm could be found. Eight years later a similar tumour was operated on in the left petrosal bone. Histological appearance, immunocytochemical findings, and the clinical context gave evidence that the tumours had to be reclassified as endolymphatic sac tumours--extremely rare entities. The report supports the hypothesis, suggested by the few earlier case reports, that endolymphatic sac tumours could be one of the inherent tumour manifestations in von Hippel-Lindau syndrome.

Carcinoma↗
PubMed1995

Antibiotic prophylaxis in cerebrospinal fluid shunting: a prospective randomized trial in 129 patients.

The efficacy of a single dose of cefotiam, a cephalosporin of the second generation, as prophylaxis for postoperative infection was analyzed in a prospective randomized study of 129 patients undergoing cerebrospinal fluid shunting. The main focus of interest was the rate of shunt infection requiring operative shunt removal. Data were evaluated in the total group and subgroups formed for normal and high risk patients, respectively. The overall rate of shunt infection was 7.5% in the cefotiam group and 12.9% in the control group. In the high risk subgroup infection rate was 14.3% with and 26.3% without cefotiam as opposed to 4.3% and 6.9%, respectively, in the normal risk subgroup. Although our results do not reach statistical significance, there is a noticeable difference of infection rate between those patients who receive the antibiotic and those who do not. Therefore, we favor single dose antibiotic prophylaxis in shunting procedures.

Adolescent↗
PubMed1995

Subarachnoid and intraventricular hemorrhage caused by hypernephroma metastasis, accompanied by innocent bilateral posterior communicating artery aneurysms.

We present a case of subarachnoid and intraventricular hemorrhage due to an infratentorial metastasis of a renal cell carcinoma. The lesion was not apparent on initial magnetic resonance imaging (MRI) or in a follow-up examination (MRI and angiography) 6 weeks after the bleeding. The innocent bilateral posterior communicating artery aneurysms detected by cerebral angiography were treated surgically. The origin of the hemorrhage, however, remained unclear. Five months later, a surgically proven metastasis in the fourth ventricle subsequently gave the explanation for the bleeding.

Carcinoma, Renal Cell↗
PubMed1994

[18FDG-PET in intracranial meningiomas versus grading, proliferation index, cellular density and cytogenetic analysis].

62 intracranial meningiomas in 60 patients were studied with 18FDG-PET prior to neurosurgery in order to evaluate the relationship between 18FDG uptake and biological aggressiveness of the tumors. Histopathological grading, cellular density, Ki-67 proliferation index and evidence of chromosomal aberrations were used to assess tumor aggressiveness. Significantly elevated 18FDG uptake was found in grade 2- and 3- compared to grade 1-meningiomas, in tumors of high cellularity compared with those of low cellularity, and in meningiomas with an elevated Ki-67 proliferation index (above 2%). The two meningiomas with the most pronounced chromosomal aberrations revealed the highest 18FDG uptake of all cytogenetically studied meningiomas. We conclude that 18FDG-PET is useful for estimating the biological aggressiveness of intracranial meningiomas.

Adult↗
PubMed1993

Frameless stereotactic drainage of intracranial abscesses.

Our preliminary experience is presented in the use of the Aachen Computer-Assisted Surgery device for frameless stereotactic puncture and drainage of intracranial abscesses through a 2.1-mm twist-drill hole. The apparatus and technique are described, along with the results of its use in 2 patients. Intraoperatively the semiactive system presents a schematic display of the drainage probe projected into a 3D model of the situs on the monitor screen corresponding to the instrument's position. As the surgeon directs the probe into the abscess the corresponding section is displayed. Thereby drainage is easily achieved under visual control.

Adult↗
PubMed1992

Computer assisted localizer for planning of surgery and intra-operative orientation.

There is discrepancy between the exact representation of anatomical structures and tumours in the CT or MRI scan and the more or less accurate intra-operative localisation methods based mostly upon landmarks of the skull and extracerebral space and visible abnormalities of the cerebral surface. To overcome these problems of exact intra-operative localisation a Computer Assisted Localizer (CAL) is presented which allows precise intra-operative orientation without these aids. It consists of a mechanically articulated arm with six degrees of freedom with a high precision digital incremental and an image processor for 3 D data of the head. MRI and/or CT investigation is done pre-operatively with four reference markers fixed on the patient's head. They are visible on the CT or MRI slices and are used as reference points during surgery for adjustment of the device. The co-ordinates of the digitalizer arm tip are projected into the corresponding axial, sagittal and coronal CT slices so that the system simultaneously presents three orthogonal multiplanar CT reconstructions with a reticule indicating the position of the tip of the arm. As the surgeon directs the arm to the region of interest the corresponding CT slices are displayed on the monitor at a rate of 20 slices/sec determined by the motion of the arm. The accuracy of measurement of the device itself lies within 1 mm. The accuracy is somewhat reduced however by the thickness of CT or MRI slices (routinely 2 mm slices were taken) and by deviations of the reference markers on the skin surface which amount up to 3 mm.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Limits of the transoral approach in craniospinal malformations.

Over a 15-year period, 15 patients with craniospinal malformations were operated on using the transoral route. Ten patients had basilar impression and five had atlantoaxial dislocation; nine patients had associated lesions. Patients treated with reposition and dorsal fusion recovered well without ventral decompression. We found that transoral odontoidectomy is suitable as a primary decompressing measure only in ventral compression or nondislocated atlantoaxial conditions.

Journal Article↗
PubMed1991

Successful treatment of a haemangioblastoma in a 95 year-old patient. Case report.

Haemangioblastomas located in the posterior fossa have rarely been described in patients older than 60 years of age. The authors report a case of a 95 year-old man who presented with an obstructive hydrocephalus secondary to a posterior fossa tumour. Computed tomography and angiography suggested intracerebellar metastasis. Despite the advanced age of the patient and his poor general condition, surgery was performed with the patient in a supine position. A haemiangioblastoma was found and completely removed. The postoperative course was without complications. This case demonstrates that the combination of modern anaesthesia, supine operating position, and the use of microsurgical techniques allow successful operations on the posterior fossa even in very old patients.

Aged↗
PubMed1991

Technical improvements in the lateral suboccipital approach for neurovascular decompression of the trigeminal and facial nerves.

Some refinements of the surgical procedure are described in 12 patients (five females, seven males) operated on for neurovascular decompression (ND) in the presence of trigeminal neuralgia and hemifacial spasm. The patients were operated upon in the supine position, in which the use of a lumbar drainage facilitates the dissection from the beginning. The lateral suboccipital approach was performed by means of a semi-osteoplastic craniotomy with the use of bone chips to close the bone defects so that a good cosmetic effect could be achieved.

Adult↗
PubMed1991

[Functional deficits of caudal cranial nerves after surgery of tumors in the foramen jugulare. A long-term follow-up study].

Jugular foramen tumors involve a critical area of the skull base. Usually they are characterized by palsy of the ninth, tenth, and eleventh cranial nerves. Depending on the extent of the tumor there are various approaches to the skull base and various surgical strategies to preserve the cranial nerves. The study is based on 31 patients who were operated on between 1982 and 1989 at the University ENT and Neurosurgery Departments in Freiburg and Mainz. The neurological findings were analyzed on admission, on discharge, and in the follow-up. While there was partial or complete dysfunction of the lower cranial nerves on discharge, long-term compensation was excellent. All patients were able to breath normally and maintain their weight by oral diet. Rerouting of the facial nerve endangers its postoperative function. Nevertheless, the long-term follow-up demonstrated excellent recovery and good functional and cosmetic results.

Adolescent↗
PubMed1991

Clinical significance of computed tomography in early aneurysm surgery.

The significance of computer tomographic findings for the analysis of complications or the course and prognosis after early aneurysm surgery was analyzed on the basis of 100 patients consecutively operated on for ruptured cerebral aneurysms. Intracerebral or extended intraventricular hematomas were a poor prognostic sign. An acute hydrocephalus had a negative effect only on the early course but not on the final results. Nearly all (94) of the patients presented postoperatively with a cerebral volume increase either by CSF release, edema, and/or vasoparalysis. A correlation with the final result could not be observed. Twenty-two patients presented with ischemic infarction in the postoperative CT scan, one had hemorrhagic infarction. In 19 of the 22 cases the cause of the infarction could be related to the surgical trauma. In 10 cases it remained asymptomatic. In only one case vasospasm was responsible for a symptomatic infarction. The findings show that early surgical repair of a ruptured cerebral aneurysm is an effective method to prevent rebleeding and ischemic infarction by vasospasm. The hemorrhage and the operation, however, are followed by a large number of visible morphological lesions in the CT scan.

Adult↗
PubMed1991

Functional deficits of cranial nerves in patients with jugular foramen lesions.

Lower cranial neuropathies are a leading presenting symptom in patients with tumors involving the jugular foramen. The purpose of this study is to assess acute and chronic functional deficits along with neurologic findings in 31 patients who underwent resection of a tumor involving the jugular foramen. Preoperative nerve dysfunction made intraoperative preservation unlikely, while postoperative lower cranial nerve dysfunction was found to be transient in many patients. Compensation of permanent dysfunction was usually excellent.

Journal Article↗