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V Seifert

Publications and source records attributed to V Seifert.

At least 73 records · Page 4Linked to original sources
PubMed1999

Preliminary experience with interactive guided brain biopsies using a vertically opened 0.5-T MR system.

The purpose of our study was to evaluate the feasibility and accuracy of brain biopsies performed within a vertically opened MR system. We worked with the interventional 0.5-T MR "SIGNA SP" (General Electric Medical Systems, Milwaukee, Wis.) with an integrated tracking device "Flashpoint Position Encoder" (Image Guided Technologies, USA). As a holding device for this instrument we constructed a special frame. The whole system allows an exact adjustment of an optimum biopsy direction and guidance of the biopsy in a non-stereotactic, interactive mode in near real-time. As biopsy tools we used MR-compatible aspiration and specially made side-cut needles (Daum, Germany; E-Z-EM, USA). We performed a prospective diagnostic brain biopsy study in 18 patients. Guidance of the needle was carried out using gradient-echo single-slice technique. The sample was taken after controlling the exact position of the needle tip on spin-echo images. In 12 cases an exact neuropathological diagnosis was possible. In 6 cases of negative biopsy (4 aspiration biopsies) the samples were not representative. Our results demonstrate the feasibility of interactive MR-guided minimally invasive brain biopsies in an open MR system. The best results were achieved using cut needles for biopsies of contrast-enhancing lesions visible on T1-weighted gradient-echo guidance sequence.

Adult↗
PubMed1999

Monitoring of intracranial compliance: correction for a change in body position.

The objectives of our study were 1. to investigate whether the intracranial compliance changes with body position; 2. to test if the pressure-volume index (PVI) calculation is affected by different body positions; 3. to define the optimal parameter to correct PVI for changes in body position and 4. to investigate the physiological meaning of the constant term (P0) in the model of the intracranial volume-pressure relationship. Thirteen patients were included in this study. All patients were subjected to 2 to 3 different body positions. In each position, either classic bolus injection was performed for measurement of intracranial compliance and calculation of PVI or the new Spiegelberg compliance monitor was used to calculate PVI continuously. Four different models were used for calculating the constant pressure term P0 and the P0 corrected PVI values. Pressure volume index not corrected for the constant term P0 significantly decreased with elevating the patients head (r = 0.70, p < 0.0001). In contrast, volume-pressure response and ICP pulse amplitude did not change with position. Using the constant term P0 to correct the PVI we found no changes between the different body positions. Our results suggest that during the variation in body position there is no change in intracranial compliance but a change in hydrostatic offset pressure which causes a shifting of the volume-pressure curve along the pressure axis without its shape being affected. PVI measurements should either be performed only with the patient in the 0 degree recumbent position or that the PVI calculation should be corrected for the hydrostatic difference between the level of the ICP transducer and the hydrostatic indifference point of the craniospinal system close to the third thoracic vertebra.

Adult↗
PubMed1999

Open MRI-guided neurosurgery.

OBJECTIVES: A number of different image-guided surgical techniques have been developed during the past decade. None of these methods can provide the surgeon with information about the dynamic changes that occur intra-operatively. MATERIAL AND METHOD: The first vertical open 0.5T MRI-scanner for intra-operative MRI-guided neurosurgery in Germany was installed at the University of Leipzig during the summer 1996. Since autumn 1996 a number of surgical procedures including biopsies (n = 31), craniotomies (n = 32), transsphenoidal procedures (n = 8) and interstitial lasertherapies (n = 3) have been performed using intra-operative MR image guidance. RESULTS: The development of MR-compatible and MR-safe non-magnetic instruments and components had to be solved. Specific surgical instruments were developed to perform biopsies, craniotomies, microsurgical tumour resections and transsphenoidal procedures in the 0.5-T open MRI. Several components required adaptation including the head holder the stereotactic navigation device, the high speed drill, the suction unit, the ultrasonic aspirator, the bipolar coagulation, the laser probe and the surgical microscope. All these newly developed technical features enable the neurosurgeon to perform a large number of surgical procedures under direct control and guidance of intra-operative MR imaging. In contrast to frame-based for framless navigation systems, intra-operative MRI provides accurate and immediate information during the progress of surgery. These intra-operative images allow definitive localization and targeting of the lesions and accommodate anatomical changes that may occur during surgery. CONCLUSION: Intra-operative MRI is helpful for navigation as well as determining of tumour margins to achieve a complete and safe resection of intracranial lesions. Complications related to the surgical procedure are reduced and the risk of neurological deterioration due to tumour removal and postoperative complications is minimized. It can be concluded that the intra-operative application of interventional MRI technology may represent a major step forward in the field of neurosurgery.

Biopsy↗
PubMed1999

Cerebellopontine angle lipoma: case report and review of the literature.

Intracranial lipomas located in the cerebellopontine angle are extremely rare. These tumours are mal-developmental lesions which can cause slowly progressive neurological symptoms. The clinical management of these tumours differs significantly from other lesions in this region. A 27 year old woman presented with a 2-month history of vertigo and a slowly progressive deterioration of hearing in the left ear. Computed tomography (CT) revealed a large low-density mass in the left cerebellopontine angle without any contrast-enhancement. In T1-weighted magnetic resonance imaging (MRI) the lesion was hyper-intense and did not enhance after application of gadolinium. Areas of lower signal intensity inside of the lesion were suggested as incorporated cranial nerves. A left retro-sigmoidal approach in a semi-sitting position was chosen to expose the tumour. After reducing the tumour mass, the tumour was dissected from the cranial nerves which were incorporated into the tumour. The residual tumour was adherent to the brain stem and the encased lower cranial nerves, allowing only a near subtotal resection of the highly vascularized tumour in order to avoid neurological deficits. The histological examination revealed a lipoma. Attempts at complete removal of cerebellopontine angle lipomas usually result in severe neurological deficits. Conservative treatment should therefore be preferred. Limited surgery is indicated if the patients suffer from disabling neurological symptoms and signs e.g., vertigo, nausea, trigeminal neuralgia, facial weakness or facial spasm.

Adult↗
PubMed1999

Serum markers of brain damage and outcome prediction in patients after severe head injury.

The objective of the study was to investigate the validity of outcome prediction after severe head injury using serum levels of S-100B protein and neuron specific enolase. Eighty-two patients with severe head injury were included in this prospective study. Venous blood samples were taken after admission and every 24 h for a maximum of 10 consecutive days. For values of S-100 from 0 to 2.5 micrograms/l, and for values of NSE from 0 to 100 micrograms/l the sensitivity and specificity of incremental values as a predictor of unfavourable outcome were calculated and Receiver Operator Characteristics curves were plotted. Serum S-100 protein was found to be clearly superior to neuron specific enolase in terms of predicting outcome with higher specificity, sensitivity, positive and negative predictive value. According to our experience, S-100B protein represents the most promising serum marker of brain cell damage currently under investigation.

Adolescent↗
PubMed1999

Intradiploic arachnoid cyst with extensive deformation of craniofacial osseous structures: case report.

OBJECTIVE AND IMPORTANCE: A unique case of a large intradiploic arachnoid cyst involving craniofacial osseous structures is reported. CLINICAL PRESENTATION: The patient presented with a hard mass in the right frontal region, proptosis, and inferior globe displacement. Computed tomography revealed an intraosseous cyst of cerebrospinal fluid intensity with extension from the anterior cranial fossa to the infratemporal fossa. INTERVENTION: After resection of the cyst wall and closure of two small round dural defects, the involved craniofacial region was reconstructed. CONCLUSION: The medical history of the patient and the intraoperative observations support the contention that the cyst in the reported case was congenital in origin. The features concerned with diagnosis and pathogenesis of this rare entity are discussed.

Adult↗
PubMed1999

Serum S-100B protein in severe head injury.

OBJECTIVE: Despite the significant recent progress in cerebral monitoring, it is still difficult to quantify the extent of primary brain injury and ongoing secondary damage after head injury. The objective of our study was to investigate S-100B protein as a serum marker of brain damage after severe head injury. METHODS: Eighty-four patients with severe head injury (Glasgow Coma Scale score < or =8) were included in this prospective study. Venous blood samples for S-100B protein were obtained as soon as possible after admission and every 24 hours thereafter, for a maximum of 10 consecutive days. Serum levels of S-100B protein were compared with outcome after 6 months, clinical variables, and the category of the Marshall classification of initial computed tomographic findings. RESULTS: Patients who died had significantly higher serum S-100B values compared with those who survived (median, 2.7 microg/L versus 0.54 microg/L; P < 0.0001, Mann-Whitney U test). Nineteen (58%) of 33 patients who died had peak S-100B values of 2 microg/L or higher, compared with 4 (8%) of the 51 surviving patients (P < 0.0005, Fisher's exact test). There was also a strong correlation between S-100B values and computed tomographic findings. Logistic regression analysis in a model with age, Glasgow Coma Scale score, intracranial pressure, and computed tomographic findings revealed S-100B as an independent predictor of outcome. Persistent elevation of S-100B levels for 2 to 6 days, even in patients with favorable outcome, may reflect ongoing secondary damage after severe head injury. CONCLUSION: S-100B may be a promising serum marker for assessing the extent of primary injury and the time course of secondary damage after severe head injury.

Adolescent↗
PubMed1999

Fatal secondary increase in serum S-100B protein after severe head injury. Report of three cases.

The S-100B protein is a small cytosolic protein that is found in astroglial or Schwann cells. It is highly specific for brain tissue and is increasingly being investigated as a diagnostic tool to assess the neurological damage after head injury, stroke, subarachnoid hemorrhage, and cardiopulmonary bypass. The authors report on three patients with severe head injury with otherwise normal cerebral perfusion pressure, SaO2, PaCO2, and controlled intracranial pressure (ICP), in whom a secondary excessive increase in serum S-100B was observed. In all cases, the S-100B increase was followed by an increase in ICP. All three patients died within 72 hours after the excessive increase in S-100B. These findings indicate that major secondary brain damage may occur at a cellular level without being identified by current neuromonitoring techniques.

Adolescent↗
PubMed1999

[Effect of local anesthetics on hemodynamic effects during Mayfield skull clamp fixation in neurosurgery using total intravenous anesthesia].

For neurosurgical procedures, the association between insertion of the Mayfield skull clamp and haemodynamic changes is generally recognized. We investigated the protective effect of two local anaesthetic substances (lidocaine and bupivacaine) under the conditions of total intravenous anaesthesia (TIVA) with propofol and alfentanil. Forty-two patients undergoing an elective craniotomy (tumor resection) were included in the study and randomly divided into three groups. All patients were given a total intravenous anaesthesia with propofol and aflfentanil. After induction, the skin areas for the pin were infiltrated with 0.9% sodium chloride (n = 14, control group 1), 1% lidocain (n = 14, group 2) or 0.5% bupivacaine (n = 14, group 3). After an interval of 1 to 2 minutes the pins were inserted. The intra-arterial line was inserted before induction. The haemodynamic parameters heart rate (HR), systolic arterial pressure (SAP), diastolic arterial pressure (DAP) and mean arterial pressure (MAP) were monitored continuously. The haemodynamic parameters were recorded at four set times: (1) after induction of anaesthesia, (2) at the onset of the local anaesthesia, (3) at the insertion of the pin-holder, (4) five minutes after insertion. Insertion of the pins led to a significant increase in HR, SAP, MAP and DAP in the control group. These haemodynamic changes can be reduced by local infiltration with lidocaine or bupivacaine. The effect of both substances was the same in our study. Our results suggest that a significant reduction of the haemodynamic effects caused by insertion of the Mayfield skull clamp can be achieved by the use of local anaesthesia. Total intravenous anaesthesia alone with propofol and alfentanil cannot protect against these haemodynamic stimuli.

Alfentanil↗
PubMed1998

[Interdisciplinary surgical therapy of tumors of the frontal skull base].

Most tumors of the anterior cranial base invade both the intra- and extracranial regions at the borderline of the cranial and facial skeleton. In surgical treatment of these lesions, combined craniofacial approaches are applied in accordance with the anatomical conditions. Surgery is performed by an interdisciplinary team of neurosurgeons and maxillofacial surgeons. To evaluate the effectiveness and the complications of this surgical concept, the data of 58 patients treated over a 10-year period were collected. In these patients, 60 operations were performed, including two operations for tumor recurrence. In 38 cases, complete tumor removal was achieved. One patient died in the early postoperative period because of pulmonary embolism. Significant neurological deficits occurred in three patients. In most cases, postoperative complications and functional disability were both due to intradural invasion of the tumor. Nevertheless, in the majority of the cases radical tumor removal is achieved with acceptable morbidity when microsurgical techniques are applied for the resection of the intradural tumor. Both the meticulous repair of dural defects and the reconstruction of the anterior cranial base and orbit contribute distinctly to a reduction in the rate of postoperative complications and to acceptable cosmetic results.

Adolescent↗
PubMed1998

[Appearance of the resection area of brain tumors in intraoperative MRI imaging].

During MRI-controlled resection of brain tumors using an open MRI system, operation-induced alterations may occur, especially enhancement of the resection cavity wall. This may simulate tumor areas, resulting in false assessment of the resection or resection of non-tumorous areas. Based on 42 MRI- and biopsy-controlled brain tumor resections in an 0.5 T open MRI (Signa SP, GE), the appearance and origin of operation-induced reactions are analyzed. In our opinion, there is a superposition of preformed peritumoral reactions by operation-induced microcontusions. The beginning of the cavity wall enhancement needs at least 10-15 min. MRI-controlled analysis of the intraoperative steps by the neurosurgeon and neuroradiologist allows discrimination of operation-induced reactions from tumor areas and leads to safe operation.

Astrocytoma↗
PubMed1998

Correlation of computed tomography findings and serum brain damage markers following severe head injury.

The objective of our study was to investigate the association between the initial levels of serum S-100B protein and neuron specific enolase and the severity of radiologically visible brain damage and outcome after severe head injury. Admission computed tomography (CT) scans of forty-four patients with severe head injury were analysed. Initial levels of S-100B protein and neuron specific enolase were compared between the different outcome groups at 6 month, the different categories of the Marshall classification, the presence of traumatic subarachnoid haemorrhage, the type of haematoma and the volume of contusion. Serum S-100B was significantly higher in patients with unfavourable outcome (1.1 micrograms/l versus 0.3 microgram/l, p < 0.005, Mann-Whitney U test). In diffuse injury, unfavourable outcome significantly increased with higher Marshall grades (p < 0.05). There was a significant correlation between the four grades of diffuse injury and initial serum S-100B protein (r = 0.48, p < 0.001). Patients with focal mass lesions and a favourable outcome after 6 month had significantly lower S-100B values than those who had an unfavourable outcome (0.51 microgram/l versus 1.3 micrograms/l, p < 0.05). A significant correlation was demonstrated between the volume of contusion visible on CT scans and serum S-100B (r = 0.58, p < 0.001). In our study, initial serum S-100B protein was a powerful predictor of outcome even within the same category of radiologically visible brain damage. Serum S-100B protein may provide independent information about the severity of primary brain damage after head injury.

Adolescent↗
PubMed1998

Endothelin and subarachnoid hemorrhage: an overview.

INTRODUCTION: Delayed cerebral vasospasm occurring after subarachnoid hemorrhage (SAH) is still responsible for a considerable percentage of the morbidity and mortality in patients with aneurysms. It has been suggested that the pathogenesis of delayed cerebral vasospasm is related to a number of pathological processes, including endothelial damage and smooth muscle cell contraction resulting from spasmogenic substances generated during lysis of subarachnoid blood clots, changes in vascular responsiveness, and inflammatory or immunological reactions of the vascular wall. It has been recognized that the endothelium plays an important role in the regulation of the cerebral vascular tone. In 1988, endothelin (ET)-1, a potent vasoconstrictor, was isolated from cultured porcine aortic endothelial cells. RESULTS: ET-1, which is one of three distinct isoforms of ETs (ET-1, ET-2, and ET-3), has a more marked effect on cerebral arteries than do the other two isoforms. Elevated levels of ETs have been demonstrated in the cerebrospinal fluid and plasma of patients after SAH and cerebral infarction. ETs act by at least three different receptor subtypes, the ET(A) receptor, which is localized in vascular smooth muscle cells and mediates vasoconstriction, and two different ET(B) receptor subtypes. The ET(B1) receptor subtype is present in vascular endothelial cells and mediates the endothelium-dependent vasodilation. The ET(B2) receptor subtype is present in smooth muscle cells causing vasoconstriction. ET-1 acts from the adventitial but not from the luminal side of cerebral arteries. In vivo and in vitro ET-1 causes a dose-dependent and long-lasting vasoconstriction, similar to cerebral vasospasm after SAH. The vasoconstriction caused by ET-1 can be reversed by selective ET(A) receptor antagonists or combined ET(A) and ET(B) receptor antagonists. CONCLUSION: The results of current clinical and experimental investigations support the hypothesis that ET-1 is a major cause of cerebral vasospasm after SAH. Other studies indicate that SAH causes complex changes in the ET system and increased ET-1 levels after SAH, which are not solely responsible for the development of vasospasm but may occur after cerebral ischemia. Further investigations are therefore needed to clarify these different hypotheses.

Animals↗
PubMed1998

Direct surgery of basilar trunk and vertebrobasilar junction aneurysms via the combined transpetrosal approach.

Surgical access to aneurysms of the basilar trunk and vertebrobasilar junction is hampered by their direct proximity of these lesions to highly vulnerable neural structures like the brain stem and cranial nerves, as well by the bony structure of the petrous bone blocking the direct surgical approach to these aneurysms. Only recently lateral approaches directed through parts of the petrous bone have been reported for surgery of basilar trunk and vertebrobasilar junction aneurysms like the anterior transpetrosal, the retrolabyrinthine transsigmoid, as well as the combined supra-infratentorial posterior transpetrosal approach. As experience in the use of this approach is limited in the neurosurgical literature we present our surgical experiences in 11 patients with basilar trunk and vertebrobasilar junction aneurysms, operated on using the supra-infratentorial posterior transpetrosal approach. In 10 patients, including one patient with a giant partially thrombosed basilar trunk aneurysm, direct clipping of the aneurysm via the transpetrosal route was possible. In one patient with a giant vertebrobasilar junction aneurysm, the completely calcified aneurysm sac was resected after occlusion of the vertebral artery. Of the whole series, one patient died and in three patients postoperative accentuation of preexisting cranial nerve deficits occurred. Except transient cerebrospinal fluid leak in two patients, the postoperative course was uneventful in the remaining patients. Postoperative angiography demonstrated complete aneurysm clipping in ten patients and relief of preoperative brain stem compression in the patient with the giant vertebrobasilar junction aneurysm. It is concluded, that the supra-infratentorial posterior transpetrosal approach allows excellent access to the basilar artery trunk and vertebrobasilar junction and can be considered the approach of choice to selected aneurysms located in this area.

Adult↗
PubMed1998

[Erwin Payr and his contributions to neurosurgery].

After having studied medicine in Vienna and worked in Graz, Greifswald and Königsberg, Erwin Payr, born February 17, 1871 in Vienna, led the Department of Surgery for nearly twenty-five years at the University of Leipzig. Under his leadership a private surgical clinic was founded, the present-day Clinic for Neurosurgery at the University of Leipzig. His surgical innovations include, among others, a new technique in the draining of brain abscesses through the use of elderberry stem capillaries, in the employment of absorbable magnesium threads for vascular and nerve sutures, as well as in the anesthetizing of the trigeminal nerve second branch in the case of trigeminal neuralgia. During the First World War he dedicated himself above all to neurotraumatic subjects such as the diagnosis and therapy of cranial and brain traumas. The reduction of elevated intracranial pressure and the creation of a passage of the cerebral fluid through the ventricle drainage in cases of hydrocephaly represented central themes of Payr's scientific works in the field of neurosurgery. Erwin Payr, recipient of manifold honors for his scientific contributions, his service as Professor and his multifaceted surgical knowledge, died in Leipzig in 1946 at the age of 75.

Austria↗
PubMed1997

Anatomic reconstruction of the posterolateral cranial base with titanium micromesh for combined transpetrosal approach: technical note.

OBJECTIVE: We describe a new technique for the anatomic closure of the posterior petrosectomy defect after the combined supra-infratentorial transpetrosal approach for petroclival lesions. METHODS: With this technique, a titanium micromesh, tailored according to the defect of the drilled petrous bone and contoured to the outer appearance of the posterolateral cranial base, is used to cover the petrosectomy area. The mesh is fixed to the cranium and to the repositioned bone flap with titanium microscrews. RESULTS AND CONCLUSION: To date, this technique has proven to be simple and rapid and has been used in 10 patients who were operated on for various tumorous and vascular lesions of the petroclival region. Excellent cosmetic results were achieved, and no technique-related complications occurred.

Basilar Artery↗