Biomedical subjects

J M Gilsbach

Publications and source records attributed to J M Gilsbach.

At least 109 records · Page 6Linked to original sources

PubMed1997

Clinical significance of three-dimensional helical CT in neurosurgery.

The authors report about a 3-years experience with helical CT and 3-D surface reconstruction applied in neurosurgical patients. All examinations were performed in addition to preexisting diagnostic CT, MRI, or angiography. The aim of this study was to assess the clinical value of this method with regard to planning of the surgical approach to anterior, middle, and posterior skull base and spinal lesions. 75 examinations of 55 patients were analysed and ranked as follows: A = examination with significant additional information for neurosurgical planning of skull base or spinal procedures or for postoperative evaluation of the neurosurgical approach, B = examination with some useful information for the neurosurgical planning or postoperative control, however, without significant advantage as compared to established diagnostic methods, C = examination without significant additional information. Classification was performed independently by two experienced surgeons. Examinations of anterior, middle, and posterior skull base lesions including cerebral aneurysms were in the majority rated as helpful and significantly informative, (A = 21, B = 24, C = 9, n = 54). Three-dimensional imaging of the spine was of clinical value only in specific cases (A = 6, B = 6, C = 9, n = 21). The authors conclude that three-dimensional imaging is a valuable diagnostic tool for pre- and postoperative imaging of tumorous and vascular lesions adjacent to the skull base, allowing for optimal surgical approaches with minimal invasiveness.

Adult↗

PubMed1997

Endovascular occlusion of experimental aneurysms with detachable coils: influence of packing density and perioperative anticoagulation.

OBJECTIVE: This study was designed to assess the intraluminal biological changes after endovascular coil occlusion of arterial aneurysms with detachable coils, to analyze the relationship between histological occlusion and mechanical packing density, and to evaluate the influence of perioperative anticoagulation on the occlusion rate. METHODS: In rabbits, 30 microsurgically produced arterial bifurcation aneurysms were occluded with coils (18 with platinum coils, electrically detached; 12 with tungsten coils, mechanically detached). Coils were placed until no further coils fit into the aneurysmal lumen and it was no longer filled with radiographic contrast material. The individual degree of occlusion was then determined by the "packing density" on the angiograms. Complete occlusion was considered only if no neck remnant was visible on the films. Anticoagulation during and 2 days after the treatment was performed in 11 cases. After an observation period ranging from 3 to 6 months, angiographic and histological analyses were performed to obtain control data. RESULTS: Complete occlusion was achieved in 9 cases, subtotal occlusion (i.e., > 95% occlusion, residual filling at the neck of the aneurysm) in 10 cases, and partial occlusion in 11 cases. Angiographically documented recanalization was detected in 14 aneurysms. In the remaining 16 aneurysms, the initially documented angiographic results were unchanged. A discrepancy between angiographic and pathological findings was frequently observed. Five of nine angiographically completely occluded aneurysms were recanalized. Endothelial-like tissue at the orifice of the aneurysm was able to be observed in only four of the nine initially completely occluded aneurysms. CONCLUSION: The results suggest that even dense packing does not always guarantee permanent occlusion, although there was a positive relationship between packing density and occlusion rate. Anticoagulation did not have any negative effect on the results.

Animals↗

PubMed1997

The computer-assisted localizer, a navigational help in microneurosurgery.

The computer-assisted-localizer (CAL) achieves a direct linkage between preoperative radiological images and individual intraoperative anatomical findings. Experiences with our system demonstrate that CAL improves the intraoperative orientation and facilitates the neurosurgical procedure. The system described here consists of a mechanical articulated robot arm with six degrees of freedom and a three-dimensional image processor. After calibration, the displayed image dynamically pointed out the exact intraoperative localization in three perpendicular sectional views. Meanwhile, CAL was successfully used in 73 selected microneurosurgical procedures.

Adult↗

PubMed1997

Ventricular dilatation in experimental intraventricular hemorrhage in pigs. Characterization of cerebrospinal fluid dynamics and the effects of fibrinolytic treatment.

BACKGROUND AND PURPOSE: Hemorrhagic ventricular dilatation (HVD) is a prominent feature of human intraventricular hemorrhage (IVH) and a strong indicator for poor outcome. We developed an IVH model to define the mechanisms responsible for HVD and to test the efficacy of intraventricular administration of tissue plasminogen activator (TPA) in the treatment of HVD. METHODS: Isolated IVH was produced in pigs by injecting 10 mL of blood simultaneously with thrombin into the right lateral ventricle. The treatment group received 1.5 mg of TPA after induction of IVH. Intraventricular blood volume and the volume of the lateral ventricles were assessed by CT after 90 minutes, 7 days, and 42 days. Intracranial pressure, the pressure-volume index, and the resistance to outflow of cerebrospinal fluid (R(out)) were measured 30 minutes and 7 days after IVH. RESULTS: After IVH, the volume of the lateral ventricles increased from 1.98 +/- 0.69 to 6.43 +/- 1.23 mL (P < .001). There was a linear relationship between ventricular and clot volume (P = .014). Initially, R(out) increased from 24.34 +/- 7.13 to 63.56 +/- 64.91 mm Hg/mL per minute (P < .001). After 7 days, restoration of normal cerebrospinal fluid circulation occurred, but the ventricles were still significantly enlarged (5.24 +/- 1.76 mL, P < .001) and filled with blood. Within 6 weeks, ventricular volume had returned to normal values, paralleled by complete clot resolution. Intraventricular administration of TPA significantly accelerated clot clearance and restoration of normal ventricle volume. CONCLUSIONS: These results suggest that intraventricular bleeding may cause impairment of cerebrospinal fluid circulation but that the mass effect of clots distending the ventricle walls is the most important mechanism responsible for HVD. This model closely imitates several prominent features of human IVH and may therefore be a useful tool for preclinical assessment of the efficacy and safety of treatment with TPA.

Animals↗

PubMed1997

Fasting improves discrimination of grade 1 and atypical or malignant meningioma in FDG-PET.

UNLABELLED: We investigated the use of PET with 2[18F]fluoro-2-deoxy-D-glucose (FDG) to discriminate between atypical or malignant and grade 1 meningiomas. The influence of fasting state and high-dose corticosteroid medication was analyzed retrospectively. METHODS: Preoperative PET scans of 75 patients with suspected diagnosis of intracranial meningioma were evaluated using standardized uptake values (SUV) and tumor-to-contralateral gray matter ratios (TGR) of FDG uptake. Fifty-one of 75 patients fasted before the PET scan, and 27 of 75 patients were studied under high-dose corticosteroid medication. Eighteen tumors had recurred. PET results were compared to histopathological grading. RESULTS: PET correctly identified 8/9 atypical or malignant meningiomas and 58/66 grade 1 meningiomas using TGR and a threshold of 1.05 in primary meningioma and 0.85 in tumor recurrence. This corresponds to a specificity of 0.88 for the detection of higher tumor grading. Specificity was significantly higher in fasting compared to nonfasting subjects (0.96 versus 0.73; p < 0.025). SUV quantification lead to a reduced specificity of 0.77 at the same level of sensitivity. The only false-negative PET finding occurred in a recurrent meningioma, which had been operated on four times before. CONCLUSION: Overnight fasting before injection is needed to improve the diagnostic accuracy of FDG-PET for noninvasive metabolic grading of meningioma. Hyperglycemia in nonfasting patients and in diabetic patients may lead to overestimation of meningioma grading.

Adolescent↗

PubMed1997

Cognition and quality of life in patients after transcallosal microsurgery for midline tumors.

OBJECTIVE: The transcallosal route has been propagated as a safe approach to midline tumors. The present study was performed in order to elucidate the neurobehavioral late sequelae in patients after transcallosal microsurgery on near-midline tumors. EXPERIMENTAL DESIGN: The present study was performed retrospectively with a delay between surgery and follow-up examination ranging from 2 to 36 months (mean 10.2 months). SETTING: The study was performed in the Department of Neurosurgery, University Hospital of the University of Technology (RWTH) Aachen, Germany. PATIENTS: A consecutive series of 18 patients treated for an intracranial lesion by transcallosal surgery was included into the study. The patients had to be not younger than 16 and not older than 67 years. The age mean was 38.9 years (range 16 to 65 years). INTERVENTIONS: The surgical approach was performed along the falx cerebi under microneurosurgical conditions with direct use of the microscope after opening the dura. MEASURES: Beyond neurological examinations, the patients were submitted to an extensive neuropsychological testing battery. Furthermore, quality of life was examined by means of a questionnaire. RESULTS: Surgery was performed without persistent new neurological deficits. Cognitive deficits were found in short- and long-term memory, motor fine-coordination, reaction time, divided attention and fronto-cortical capacity. The quality of life was particularly impaired in the area of cognitive capacity in daily life. These findings could be related to the duration of preoperative symptoms and to the tumor location. CONCLUSIONS: The deficits found cannot be explained by surgical damage to the corpus callosum itself. Rather, they seem to correspond to an extra-callosal pathology. Further studies with a prospective evaluation of larger patient samples are called for in the future.

Adolescent↗

PubMed1997

[Forum: Clips and coils in aneurysm treatment].

The treatment of cerebral aneurysms aims at the complete elimination of the aneurysm from the circulation. In the case of subarachnoid hemorrhage (SAH), early management prevents rebleeding and in incidental aneurysms, future rupture is to be prevented. Standardization of surgical techniques and optimized collateral measures have reduced the morbidity and mortality of early operations in SAH to 10% and 15%, respectively, in most series. As an alternative, endovascular techniques are being developed which attempt to obliterate the aneurysmal sack by packing it with detachable platinum-coils. A major difference between clipping and coiling is the closure of the aperture by the surgical clip which approximates the vessel walls. During coil embolization, that aperture stays open, allowing in some cases further compaction of the coils in subsequent months and years. Recanalization attributable to compaction depends on the size of the aneurysm and may necessitate repacking in up to 40% of the cases (aneurysms > 25 mm). As for the risk of rebleeding, a recanalized aneurysm is comparable to a partially clipped aneurysm. As the surgical results from early and delayed operations were obtained in randomized controlled studies, such randomized comparative studies will need to be applied to assess the value and risks and long-term results of endovascular strategies.

Aneurysm, Ruptured↗

PubMed1996

Microsurgical management of ventral and ventrolateral foramen magnum meningiomas.

The authors report their experiences gained from 19 patients with ventral or ventrolateral foramen magnum meningiomas operated on via the dorsolateral, suboccipital transcondylar access route. It is emphasized that the microsurgical management of these lesions includes two important aspects which increase the safety of the procedure: a meticulous preoperative planning based on the microanatomical details of each patient, as well as an individualized tailoring of the surgical approach. There were no deaths, and, in the past 5 years, no neurological complications in this series. Gross total removal of the tumour was achieved in each case. It is concluded that microsurgical removal of ventral or ventrolateral foramen magnum meningiomas with this technique constitutes a safe and recommendable procedure.

Aged↗

PubMed1996

PET-study of intracranial meningiomas: correlation with histopathology, cellularity and proliferation rate.

The glucose metabolism of 62 meningiomas was measured by fluorine -18-2-fluorodeoxyglucose (FDG) PET and correlated with proliferation rate (Ki-67 index) and tumor cellularity. The mean metabolic rate (MRGlu) for meningiomas was 0.26 +/- 0.13 mikromol/g/min (range 0.08-0.62 mikromol/g/min). The relative tumor FDG-uptake (Q-MRGlu) (tumor/contralateral cortex) of all meningiomas was calculated with 0.73 +/- 0.37 (0.24-1.79). Differences of Q-MRGlu were significant between the groups with high vs. low cellularity (p < 0.01), increased vs. normal proliferation rate (p < 0.025) and low (WHO grade I) vs. higher (WHO grades II, III) graded tumors. In recurrent meningiomas (14 tumors) the glucose metabolism was not increased. The data show that 18 FDG-PET is suitable to serve as non-invasive predictor of tumor growth characteristics in meningiomas.

Adult↗

PubMed1996

Hemangioblastomas of the spinal cord and the brainstem: diagnostic and therapeutic features.

Hemangioblastomas of the spinal cord and the brainstem make up 4% of all spinal tumors and are less common than cerebellar hemangioblastomas. CT and MRI are essential for preoperative diagnosis. Nevertheless, cerebral and spinal angiography are also mandatory, since they allow a detailed study of the vascular situation, which is decisive for exact planning of a surgical strategy. The purpose of this study was to evaluate the diagnostic and therapeutic factors which influence surgical morbidity and postoperative outcome. Twelve patients harbouring spinal(8 cases) or medullary (4 cases) hemangioblastomas, all symptomatic with sensorimotor deficits corresponding to the level of the lesion were evaluated. All patients were treated in our department between December 1989 and September 1994. Complete resection of the lesion was achieved in each case. Postoperatively, none of the patients showed deterioration. Nine patients had immediate postoperative improvement of neurological signs and symptoms; in three patients the initial neurological deficits remained unchanged during the in-patient period. Late postoperative outcome demonstrated a clear improvement; in only one patient was there no change of the clinical signs, while in the other 11 patients a significant improvement of pre-existing neurological deficits was experienced. We conclude that microsurgical resection of spinal and medullary hemangioblastomas with low morbidity is feasible.

Adult↗

PubMed1996

Early neuropsychological sequelae of aneurysm surgery and subarachnoid haemorrhage.

In order to disclose the immediate cognitive sequelae of early aneurysm surgery and subarachnoid haemorrhage (SAH), a series of 28 patients was examined neuropsychologically one to 13 days (median 5 days) after surgery. Cognitive deficits emerged in short- and long-term memory, language and in different functions of attention. There was no effect of ACoA aneurysm location on neuropsychological test performance. No substantial effect of premature aneurysm rupture or surgical approach could be revealed. Temporary clipping of vessels was associated with significantly worse selective attention and phasic alertness (p < 0.05, respectively). Partial resection of the gyrus rectus led to a worse short-term memory (p = 0.02). In regression analyses, the duration of temporary clipping was associated with worse short-term memory (adjusted r2 = 0.68; p = 0.007) and decreased phasic alertness (adjusted r2 = 0.47; p = 0.035). The clinical state on admission (Hunt and Hess) predicted an impaired phasic alertness (adjusted r2 = 0.43; p = 0.004). It is concluded from the results, that certain procedures and events in aneurysm surgery can have neuropsychological effects. The present study is restricted by the small sample size. Therefore, a prospective study with a larger patient sample is required for further confirmation of the present findings.

Adult↗

PubMed1996

Osteoplastic frontal sinusotomy and extradural microsurgical repair of frontobasal cerebrospinal fluid fistulas.

The choice of the surgical approach and operative technique for the management of cerebrospinal fluid (CSF) fistulas of the anterior cranial fossa are still a controversially discussed topic. Although "extracranial" approaches through the paranasal sinuses are becoming increasingly more popular among otolaryngologists and maxillo-facial surgeons, most neurosurgeons traditionally prefer the "intracranial" repair of CSF fistulas by a craniotomy. We present an approach through the frontal sinus for the repair of dural defects behind the posterior wall of the frontal sinus and at the floor of the anterior cranial fossa. The operative procedure comprises the following main steps: 1) exposure of the anterior wall of the frontal sinus by a bicoronal incision; 2) excision of the anterior wall without frontal burr holes; 3) bilateral removal of the posterior wall of the frontal sinus; 4) extradural inspection of the dura behind the frontal sinus and above the cribriform plate, ethmoidal roof, and orbital roof bilaterally; 5) closure of dural tears by direct suture and a periosteal graft; 6) reinsertion of the anterior wall of the frontal sinus and fixation with titanium micro plates. Twenty-five patients operated upon using this technique are described. The aetiology of the frontobasal lesion was traumatic in 23, and an ethmoid carcinoma in two. In all patients, the dural fistulas were successfully repaired during the initial procedure. One patient died from sudden circulatory arrest after an uneventful postoperative course of nine days. Otherwise, there were no postoperative complications. This technique affords atraumatic extradural inspection and repair of dural fistulas bilaterally behind the frontal sinus, and above the cribriform plate and the ethmoidal and orbital roofs with none or minimal brain retraction. It therefore allows early repair of CSF fistulas also in patients with severe brain injury. Although we consider the extradural closure of fistulas the method of choice, this approach also allows for a combined extradural-intradural procedure, thus enabling the surgeon to treat associated intradural pathologies, such as traumatic lesions or tumours of the frontal cranial base.

Adolescent↗

PubMed1996

[Management of craniocerebral trauma in a neurosurgery center].

Aggressive treatment of patients with severe head injury increases the chance for survival and good functional outcome in most cases. To prevent irreversible cerebral lesions, the key point of treatment is the management of intracranial hypertension caused by intracranial hematomas, brain edema and impaired circulation of cerebrospinal fluid (CSF). Therapeutic standards are surgery of traumatic hematoma, osmotherapy and mild hyperventilation for brain edema, and CSF drainage. In highly elevated intracranial pressure (ICP) administration of barbiturates and forced hyperventilation can be considered.

Brain Injuries↗

PubMed1996

[Lumbar dislocation fracture with paraplegia after pelvic seat belt injury. Case report].

This report details a traumatic spinal column lesion due to a lap seat belt. A healthy 22-year-old woman was involved in a car accident and suffered a lumbar luxation fracture at the level L1-L2. She developed acute transsectional symptoms with paraplegia and severe hyperpathia in her legs. Plain radiographs (antero-posterior and lateral projection) and lumbar CT scans demonstrated an instable flexion-distraction fracture with ventral compression of the vertebral body of L2 and ventrolisthesis of L1 over L2. Surgical reposition of the luxation fracture and removal of a spinal epidural hematoma was performed 4 h after the trauma. Stabilization was achieved by monosegmental dorsal transpedicular spondylodesis with a fixateur interne. In follow-up the neurological deficits markedly improved. Six months after the trauma, the patient is able to walk, has no paresis and no genitourinary disturbances: only mild dysesthesia remains. This posttraumatic course confirms that spinal traumas below L1 which spare the conus have a favorable prognosis, because the peripheral nerves of the cauda equina are able to recover. This injured patient was the only one using a lap seat belt; the other four passengers in the same compact car-wearing lap and diagonal seat belts-suffered no harm. We conclude that lap seat belts are not acceptable as an adequate security standard in modern automobile technology.

Adult↗

PubMed1996

Microsurgical interhemispheric approach to dural arteriovenous fistulas of the floor of the anterior cranial fossa.

Six patients with a dural arteriovenous fistula (DAVF) of the floor of the anterior cranial fossa underwent microsurgical treatment. Two of them were operated using a conventional frontobasal approach, and four using an interhemispheric approach. The interhemispheric approach offers the advantages of sparing the frontal sinus, minimizing frontal lobe retraction, and providing a visual angle perpendicular to the floor of the anterior fossa and an excellent view of the fistula located on the cribriform plate at the level of the foramen caecum. Using the interhemispheric route, the malformation was occluded in all the cases by dividing the vascular connection between the dura of the cribriform plate and the intradural draining vein. There were no complications related to the surgical procedure. This route avoids some disadvantages of the more frequently reported frontobasal approach. It is therefore a recommendable alternative for the management of frontal DAVFs.

Adult↗

PubMed1996

Interhemispheric approach for microsurgical removal of olfactory groove meningiomas.

Eighteen consecutive patients with olfactory groove meningiomas, with diameters ranging from 1.5 to 7 cm, underwent microsurgical tumour resection using a unilateral frontal interhemispheric approach. Unilateral frontal craniotomy, superior to the frontal sinus, exposing the superior sagittal sinus was performed. The ipsilateral frontal lobe was gently retracted laterally, and the tumour resected through the gap between the falx and the medial aspect of the frontal lobe, anteriorly to the genu of the corpus callosum. Gross total tumour resection was achieved in all the patients. There was no evidence of damage to the frontal lobes, the anterior cerebral arteries or the optic system. Compared with the more commonly applied subfrontal route, the interhemispheric approach has the advantages of sparing the frontal sinuses and providing excellent overview of the dissection of the anterior cerebral arteries and the optic system, as well as for the resection of tumour invading the frontal cranial base.

Aged↗

PubMed1996

Microsurgically produced bifurcation aneurysms in a rabbit model for endovascular coil embolization.

The authors present a detailed account of the microsurgical production of bifurcation aneurysms in chinchilla rabbits for basic studies of endovascular coil embolization of aneurysms. End-to-side anastomoses of both common carotid arteries (CCAs) were performed, and a venous pouch was fitted into the newly created bifurcation. These experimental aneurysms closely mimic human cerebral aneurysms in size and hemodynamic features. Sixty-three animals underwent operation. Fifteen animals died in the course of the experiment and 15 were excluded because of a CCA occlusion within the carotid bifurcation. Electrical detachable platinum coils, also known as Guglielmi detachable coils (GDCs), and tungsten mechanical detachable coils (MDCs) were used for the endovascular occlusion of 26 bifurcation aneurysms (16 rabbits were treated with GDCs and 10 with MDCs). Initially, complete angiographic obliteration (95%-100% occlusion of the aneurysm) was achieved in nine rabbits and incomplete obliteration (< 95% occlusion) was seen in 17 animals. Final angiography 3 to 6 months later demonstrated complete occlusion in only four and partial occlusion in 22 aneurysms. At present, the histopathological examination of 17 embolized aneurysms has revealed incomplete obliteration of all aneurysms, even in those three cases that were thought to be completely embolized according to angiographic criteria. A general overestimation of the radiological degree of aneurysm obliteration was found.

Animals↗

PubMed1995

Cavernous angiomas of the spinal cord clinical presentation, surgical strategy, and postoperative results.

Nine consecutive cases of surgically treated spinal cavernous angiomas are presented. Our series consists of 6 men and 3 women with the following intramedullary spinal location of the cavernomas: 4 cervical, 4 thoracic and 1 thoraco-lumbar. All 9 patients were symptomatic with signs of myelopathy and senorimotor deficits corresponding to the level of the lesion. Six patients underwent laminectomy and in three patients a hemilaminectomy was performed to approach the lesion. A complete resection of the cavernoma was achieved in each case. Five patients showed transient neurological deterioration, in three cases the neurological status remained unchanged, and one patient experienced a slight improvement of symptoms during the early postoperative period. At follow-up examination (mean 14 months postoperative), a clear improvement of the clinical signs was demonstrable in 6 patients, and a complete resolution of the pre-existing symptoms and signs was achieved in two individuals. In one case the clinical state remained unchanged. It is concluded that microsurgical resection is the treatment of choice in cavernomas of the spinal cord.

Adult↗