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J Meixensberger

Publications and source records attributed to J Meixensberger.

At least 37 records · Page 2Linked to original sources
PubMed2005

Evaluation of intra-operative ultrasound imaging in brain tumor resection: a prospective study.

AIMS: The purpose of our study was to evaluate intra-operative ultrasound (IOUS) as a tool of resection control after brain tumor surgery. In addition, we looked for tumor species suitable for ultrasound representation. METHODS: Using a Siemens Omnia Sonoline Ultrasound, 36 tumors were examined, high-grade gliomas (62%), metastases (22%) and others (16%). We focused on tumor imaging by ultrasound with regard to its reliability of tumor expansion and margins. Evaluation of the images was carried out by correlating the ultrasound-based intra-operative measured tumor volume before and after resection with a pre- and post-operative (within 48 hours) measured volume by MRI. The IOUS measurements were performed by the neurosurgeon and the MRI measurements by the neuroradiologist. Thus, the measurement procedures were blinded. Corresponding to a deviation of the ultrasound volume by 10, 20 and > 20% from the MRI volume, the correlation was ranked good, moderate and poor. For assessing the agreement between these two methods of imaging, the statistical analysis was conducted using a method described by Bland and Altman. RESULTS: High-grade gliomas mostly showed a moderate or poor correlation in comparing IOUS- and MRI-tumor volumetry resulting in incomplete resection. Metastases resulted in a good to moderate correlation with a satisfactory extent of resection. The other tumors had poor images with larger tumor residues. The MRI measured volumes tended to be larger on average; the deviation grew with tumor size . CONCLUSION: The reliability of IOUS depends on tumor type. It is beneficial to use IOUS for the resection of metastases and a few high-grade gliomas. Concerning the volumetric accuracy, the value of IOUS is worse than its value of navigation and resection control.

Adolescent↗
PubMed2004

[Preoperative imaging as the basis for image-guided neurosurgery].

With the progressive development of soft- and hardware, the acceptance of image-guided neurosurgery has increased dramatically. Additional image data are required to analyze the nature and the dimensions of pathological processes and the surrounding tissue. In this context, fMRI, SPECT, PET, as well as special modalities of CT and MR imaging, are routinely used. Secondary post-processing options are used to detect intracerebral lesions as well as adjacent functional eloquent regions in the parenchymatous organ pre- and intraoperatively. The integration of different image information guarantees the precise planning and realization of surgical maneuvers. The segmentation of interesting structures and risk structures, as well as their implementation in the neuronavigation systems, help to avoid additional intraoperative traumatization and offer a higher level of safety and precision. In this article the value and limitations of presurgical imaging will be discussed.

Brain↗
PubMed2004

Fatal bihemispheric intracerebral hemorrhage after burrhole evacuation of chronic subdural hematoma in a bone marrow-transplanted patient: case report and review of the literature.

BACKGROUND: Intracranial hemorrhage seems to be a relatively frequent complication following bone marrow transplantation (BMT). The neurosurgical management of these patients can be problematic. CASE DESCRIPTION: We report about a 46-year-old patient, who had BMT because of a Pre-T-ALL and who developed symptomatic bihemispheric chronic subdural hematomas (cSDHs). Pre-T-ALL is a form of an acute lymphatic leukemia of T cell type characterized by certain immunologic markers with a worse prognosis. A few hours after evacuation of the cSDHs, the patient developed a fulminant intracerebral hemorrhage on each hemisphere and expired 2 days later. We reviewed the literature reporting similar cases to discuss the indication for a neurosurgical intervention. CONCLUSION: We presume a higher incidence of intracranial hemorrhage in BMT patients than reported. This is caused by the pathologically altered parenchyma related to the extensive therapy in these patients. BMT patients are typically at high risk for intracranial bleeding and are treated conservatively or surgically. We cannot generally recommend the conservative management for symptomatic subdural hematomas/hygromas. The risk for an acute worsening, secondary to repeated hemorrhage, is equivalent to the risk of surgical intervention. Although the outcome of our case is tragic, it should not deter surgical intervention.

Bone Marrow Transplantation↗
PubMed2004

Cavernous malformations--navigational supported surgery.

OBJECTIVE: Navigational supported surgery of intracranial lesions is expected to be associated with a lower rate of brain traumatization as well as an avoidance of additional neurological deficits and surgical morbidity. In our study we used the computer-assisted image guidance for resection of cerebral cavernous malformations. METHODS: In all patients the planning procedure for the following image-guided surgery was realized using preoperative MRl data sets and a neuronavigation system (STP 4.0, SNN). In cases in which the cavernoma was situated near functional eloquent regions, functional MR images were fused preoperatively. RESULTS: During the last 24 months, 21 patients were surgically treated for cerebral cavernoma. No patient was operated twice. The mean size of cavernoma was 18.3 mm, ranging from 5 to 60 mm, the mean distance between cortical surface and cavernoma was 26 mm, ranging from 5 to 50 mm. The surgical procedure lasted in the median 180 min. All patients showed an identical or better neurological outcome. CONCLUSIONS: Neuronavigation allows an accurate definition of the intraoperative target, a correct approach and a safe surgery. With the help of neuronavigation the surgical approach and the extirpation of cavernous malformations were realized in a comfortable and safe way and allowed a minimization of tissue manipulation.

Adolescent↗
PubMed2004

[Post-processing of radiological data for preoperative planning in skull base surgery].

Preoperative planning in skull base surgery is usually based on numbers of different radiological data. To use this complex data digital post-processing is necessary. There is a significant difference between radiological and surgical post-processing. Planning the approach, resection of the tumour and reconstruction of the defect are supported by the software demonstrated in this study. Integration of the results in a closed workflow of Information-Guided Therapy will increase the potentials of surgical post-processing in the future (i. e. intraoperative navigation and visualization). Evidence based medicine will use digital data of surgical planning.

Carcinoma, Adenoid Cystic↗
PubMed2004

Third ventriculostomy in communicating hydrocephalus in adult patients -- the role of lumbar and cranial cerebrospinal fluid outflow measurement.

OBJECTIVE: To evaluate the value of CSF outflow resistance testing as a criterion for endscopic treatment in case of communicating hydrocephalus. METHODS: 12 patients with communicating hydrocephalus were integrated in a prospective study from 1999 - 2001. Under the assumption of different hydromechanical properties of both spinal and cerebral CSF compartment the resorption capacity was measured. V.-p. shunting, ventriculostomy or conservative treatment were performed dependent on the results and clinical outcome was evaluated. RESULTS: Six patients with pathological lumbar testing underwent primary ventriculo-peritoneal shunting. In 6 of the 12 cases the lumbar CSF resorption capacity was found to be normal and cerebral testing was accomplished. Two patients with normal spinal and cerebral resorption capacity were not operated. In the remaining 4 patients cerebral testing was found to be pathological and ventriculostomy was performed. An improvement of clinical symptoms was observed in patients operated with a v.-p. shunt and in the VCS group as well. CONCLUSIONS: This study demonstrates that there is a subgroup of patients with morphological communicating hydrocephalus that is characterized by a functional dissociation of hydromechanical properties of intracranial and spinal CSF compartment. In cases of regular CSF resorption but restricted CSF outflow from the ventricular system to the subarachnoid space ventriculo-peritoneal shunting may be an efficient therapy, but VCS was proved to be an efficient alternative.

Aged↗
PubMed2004

[Catecholamine levels in plasma and cerebrospinal fluid of neurosurgical patients with normal and elevated intracranial pressure].

OBJECTIVE: Catecholamine levels in the plasma and cerebrospinal fluid of 21 neurosurgical patients with hydrocephalus and with normal and elevated intracranial pressure were determined prospectively in a clinical study. METHODS: The study comprised 11 patients with normal intracranial pressure (8 female, 3 male, group 1) and 10 patients with elevated intracranial pressure (6 female, 4 male, group 2). The patients underwent a ventriculo-peritoneal shunt operation, external ventricular drainage or ventriculocisternostomy. The measuring times were set as follows: time 1: pre-operative; time 2: intra-operative; time 3: post-operative. The anaesthetic for the operations was administered as a total intravenous anaesthesia with propofol and alfentanil, muscle relaxation being achieved with rocuronium bromide or cis-atracurium. RESULTS: Measurements of the catecholamine levels (adrenaline, noradrenaline and dopamine) at the three set times revealed an intra-operative fall compared to the initial pre-operative value and a rise in the catecholamine level again after the operation. It is likely that this largely reflects the course of the anaesthetic. The fall in the plasma catecholamine level was much slighter in group with elevated intracranial pressure. But in the group of patients with elevated intracranial pressure the catecholamine levels found in the plasma were much higher than those of the patients without elevated pressure. In the case of adrenaline, it was possible to demonstrate a statistically significant difference at the three measuring times. This suggests that especially the analyzed adrenaline level in the plasma could take on the role of a marker in cases of elevated intracranial pressure. In group 2, with elevated intracranial pressure, the catecholamine levels in the cerebrospinal fluid (CSF) were considerably higher than those in group 1, but the difference did not reach the significance level. The lack of correlation between the catecholamine values in the plasma and CSF described in the literature (comparison of the corresponding values at time 2) was confirmed for noradrenaline and dopamine in patients with elevated intracranial pressure (group 2). In both groups of patients there was a CSF plasma gradient for dopamine at time 2, i. e. the dopamine level was higher in cerebrospinal fluid than in the plasma. CONCLUSION: The study shows that even a slight rise in intracranial pressure without clinically detectable ischaemia may result in elevated plasma and CSF catecholamine levels. Although catecholamine values are not routine parameters, they can be used in developing procedures to protect the brain in neurosurgical patients.

Adult↗
PubMed2004

Influence of cerebral oxygenation following severe head injury on neuropsychological testing.

Despite recent advances in the management of severe head injury the mortality and morbidity remains high. Intracranial pressure (ICP) and cerebral perfusion pressure (CPP) are crucial parameters for the correct management at the intensive care unit, due to their therapeutic and prognostic importance. In addition, regional brain tissue oxygenation (ptiO2) seems to be of importance. While different studies demonstrated the impact of cerebral hypoxia on outcome (mortality), no data are available focusing on morbidity (neuropsychological deficits). Therefore, our study is carried out to demonstrate a possible relationship between amount of cerebral oxygenation during acute stage after severe head injury and neuropsychological outcome. Besides ICP and CPP, ptiO2 was monitored in 40 severely head injured patients during the ICU stay from the day of admission until day 10. Monitoring data were stored and amount of hypoxic episodes were calculated. Besides outcome using the Glasgow Outcome Scale neuropsychological testing was performed 2-3 years after injury. Analysing the quality of brain tissue oxygenation, a relationship to the performance in neuropsychological tests could be found. Patients with low brain tissue oxygenation had a worse outcome in neuropsychological testing, especially concerning intelligence and memory. Associated with these deficits patients showed a reduced performance in their profession. Our data suggest a possible predictive value of brain tissue oxygen on morbidity analysing neurocognitive function after head injury. This may implicate monitoring and treatment of cerebral hypoxia.

Adolescent↗
PubMed2003

Clinical results in MR-guided therapy for malignant gliomas.

The prognostic impact of the extent of tumour resection in surgery of malignant glioma patients remains controversial. We report the results of cumulative survival of malignant glioma patients operated with MR-guidance. Patients with complete tumour removal were compared with a population of patients with incomplete tumour removal. A 0.5 T scanner was used to criticize the extent of resection during surgery. In total no significant difference could be found, however there is a tendency that complete tumour removal seems to be associated with a slightly increased median survival time.

Adult↗
PubMed2003

Improving planning procedure in brain biopsy: coupling frame-based stereotaxy with navigational device STP 4.0.

37 consecutive patients with space-occupying intracerebral lesions were operated via frame-based stereotaxy. After CT-localizing of suspect lesions and computer-supported definition of entry and target coordinates a serial stereotactic biopsy was performed. Biopsy specimens allowed a satisfactory neuropathological examination and diagnostic result in 36 cases (97 %). Only three patients (8.1 %) showed an intraoperative bleeding, which was not associated with any postoperative CT-detectable hematoma, neurosurgical intervention nor with any neurological deficits. In summary we described the method of a computerized planning technique for stereotactic biopsy with the use of a special stereotactic planning program. High percentage of satisfactory neuropathological diagnoses and comfortable and accurate definition of target and entry coordinates justify computer support as a routine method.

Adolescent↗
PubMed2003

Effects of decompressive craniectomy on brain tissue oxygen in patients with intracranial hypertension.

This report examined the intraoperative course of partial pressure of brain tissue oxygen (P(ti)O(2)) and intracranial pressure (ICP) during surgical decompressive craniectomy for medically intractable intracranial hypertension due to diffuse brain swelling in three patients after severe subarachnoid haemorrhage and aneurysm coiling. The mean ICP decreased from 59 mm Hg to 10 mm Hg in a two step fashion, relating to bone flap removal and dural opening. Simultaneously, P(ti)O(2) increased rapidly from 0.8 kPa (6 mm Hg) to 3.07 kPa (23 mm Hg). P(ti)O(2) and ICP remained at non-critical ranges postoperatively. Despite these beneficial effects on ICP and P(ti)O(2), the patients' clinical status remained poor with two in a persistent vegetative state and one dead.

Adult↗
PubMed2003

Brain tissue oxygen guided treatment supplementing ICP/CPP therapy after traumatic brain injury.

OBJECTIVE: To evaluate the effects of a brain tissue oxygen (P(ti)O(2)) guided treatment in patients with traumatic brain injury. METHODS: P(ti)O(2) was monitored in 93 patients with severe traumatic brain injury. Forty patients admitted from 1993 to 1996 were treated with intracranial pressure/cerebral perfusion pressure (ICP/CPP) management alone (ICP < 20 mm Hg, CPP > 70 mm Hg). Fifty three patients admitted from 1997 to 2000 were treated using ICP/CPP management, but in this second group CPP was also increased as individually required to raise the P(ti)O(2) above 1.33 kPa (10 mm Hg) (P(ti)O(2) guided group). RESULTS: Cerebral hypoxic phases with P(ti)O(2) values below 1.33 kPa occurred significantly less often in the P(ti)O(2) guided group. P(ti)O(2) values were higher over the whole monitoring period. No statistical differences could be observed in outcome at six months, despite a positive trend in the P(ti)O(2) guided group. CONCLUSIONS: Cerebral hypoxic events can be reduced significantly by increasing cerebral perfusion pressure as required. To show a clear beneficial effect of P(ti)O(2) guided cerebral perfusion pressure management on outcome, a multicentre randomised trial needs to be undertaken.

Adult↗
PubMed2002

Therapeutic aspects of brain tissue pO2 monitoring after subarachnoid hemorrhage.

Prolonged phases of brain tissue hypoxia (ptiO2 < 10 mmHg) lead to cerebral infarction. Therefore, the present study investigates the role of ptiO2--monitoring to guide hypervolemic hypertensive therapy in patients suffering from severe subarachnoid hemorrhage (SAH). Besides transcranial doppler, neuromonitoring of ICP/CPP was supplemented by ptiO2 monitoring. The ptiO2 catheter was inserted into viable tissue in the vascular territory with the highest risk for vasospasm. Patients were divided in an infarction (n = 21) and a non-infarction group (n = 11). Critical CPP (< 70 mmHg) as well as hypoxic ptiO2 (< 10 mmHg) was significantly more frequent in the infarction group (CPP: 25 vs 13%, p < 0.001; ptiO2: 16 vs 7%, p < 0.001). In both groups, over 25% of the critical ptiO2 values occurred at a CPP > 90 mmHg. In the infarction group, 13 patients showed transient phases of hypoxia which normalized under induced hypervolemic hypertension and 5 patients developed persistent hypoxia. In the non-infarction group 6 patients showed transient hypoxia and in 5 patients no hypoxic values could be found. In conclusion, monitoring of ptiO2 provides an additional independent parameter to detect hypoxic events and to guide therapy.

Cell Hypoxia↗
PubMed2001

Advanced neuromonitoring including cerebral tissue oxygenation and outcome after traumatic brain injury.

For 51 patients suffering from traumatic brain injury (GCS < 9), we compared the prognostic value of critical parameters derived from neuromonitoring of intracranial pressure (ICP), cerebral perfusion pressure (CPP) and brain tissue oxygenation (PiO2) during different time periods after trauma (< or = 12, < or = 24, < or = 48, < or = 72 and < or = 96 h). For patients with good outcome (GOS = 4-5, n = 30) the proportion of critical ICP values (> 40 mmHg) was about 0.2% during all time periods. The corresponding proportions for patients with bad outcome (GOS = 1-3, n = 21) rose from 0.2% to 4.7% during increasing time periods. The frequency of critical ICP values was significantly related to outcome (p < 0.001) for time periods > 48 h after trauma. Differences of critical CPP (< or = 50 mmHg) and hypoxic PiO2 (< or = 5 mmHg) between both outcome groups were less pronounced and for both parameters significant relations to outcome were only obtained for the longest time period (< or = 96 h, p < or = 0.05). Higher thresholds for CPP (< or = 60 mmHg, < or = 70 mmHg) did not reveal any relation to outcome. For all neuromonitoring parameters significant relations between the frequency of critical values and outcome could be determined. Critical ICP values provide the earliest and highest prognostic power, while critical CPP and hypoxic PiO2 only showed prognostic power in later time periods.

Adolescent↗
PubMed2001

Clinical cerebral microdialysis: brain metabolism and brain tissue oxygenation after acute brain injury.

While continuous monitoring of brain tissue oxygenation (P(ti)O2) is known as a practicable, safe and reliable monitoring technology supplementing traditional ICP-CPP-monitoring, the impact of cerebral microdialysis, now available bedside, is not proven extensively. Therefore our studies focused on the practicability, complications and clinical impact of microdialysis during long term monitoring after acute brain injury, especially the analysis of the correlation between changes of local brain oxygenation and metabolism. Advanced neuromonitoring including ICP-CPP-p(ti)O2 was performed in 20 patients suffering from acute brain injury. Analysis of the extracellular fluid metabolites (glucose, lactate, pyruvate, glutamate) were performed bedside hourly. No catheter associated complications, like infection and bleeding, occurred. However, longterm monitoring was limited in 5 out of 20 patients caused by obliteration of the microdialysis catheter after 3-4 days. In the individual patients partly a correlation between increased lactate levels as well as lactate pyruvate ratios and hypoxic brain tissue oxygenation could be found. Analysing the data sets of all patients only a low correlation was detected indicating physiological and increased lactate and lactate/pyruvate ratio during sufficient brain oxygenation. Additionally, concentrations of excitatory amino acid glutamate were found in normal and elevated range during periods of hypoxic oxygenation (P(ti)O2 < 10 mmHg) and intracranial hypertension. Our data strongly suggest partly evidence of correlation between hypoxic oxygenation and metabolic disturbances after brain injury. On the other hand brain metabolism is altered without changes of cerebral oxygenation. Further studies are indicated to improve our pathophysiological knowledge before microdialysis is routinely useful in neurointensive care.

Adolescent↗
PubMed2000

Prognostic significance of advanced neuromonitoring after traumatic brain injury using neural networks.

While the therapeutic impact of tissue oxygenation (PtiO2) supplementing ICP-monitoring is proven by several clinical studies, its prognostic value is not well studied. In the following study artificial neural networks (ANN) were used to analyze the accuracy of outcome prediction after traumatic brain injury (TBI) for different combinations of clinical data and parameters derived from neuromonitoring. The total group included 95 patients suffering from TBI. For all patients clinical data (age, GCS, pupillary response etc.) were recorded and outcome was classified using Glasgow outcome scale after 6 months. In a first step a subgroup of 60 patients was chosen to train a neural network to predict outcome based only on clinical data. In a second step the resting 35 patients all having continuous neuromonitoring with automatic data storage of ICP and PtiO2 were chosen. Different network models were composed using the former clinical model plus up to three additional input units for the following parameters: (a) relative number of ICP > 40 mmHg, (b) relative number of PtiO2 < 5 mmHg and (c) relative number of ICP > 30 mmHg with simultaneous PtiO2 < 10 mmHg. For each model the following time periods were analyzed: day 1-2, day 1-3 and day 1-4 after trauma and additionally day 1-4 after trauma plus last day of neuromonitoring. Pure clinical data allowed to predict outcome with 74.3% accuracy. A combination of clinical data with ICP (a) significantly increased the confidence levels of outcome prediction in all time periods (p < 0.05) with accuracy rates rising up to 82.9% for the longer time periods. The combination of clinical data and ICP & PtiO2 (c) lead to comparable results. In contrast, no significant increases were observed in the early time periods when combining clinical data with PtiO2 (b) while accuracy rates rose up to 80% for extended time periods after trauma. A combination of all parameters lead to results lying between the above results. The results indicate that prediction of outcome can be improved by combining clinical and neuromonitoring data. The prognostic value of ICP might be superior to that of PtiO2.

Brain Injuries↗
PubMed2000

Near-infrared spectroscopy--not useful to monitor cerebral oxygenation after severe brain injury.

Since its development more than twenty years ago, non-invasive near-infrared-spectroscopy (NIRS) has been widely used to monitor cerebral oxygenation. Despite of its growing number of users, the diagnostic value of near-infrared spectroscopy still remains unclear, especially in case of acute brain injury and long-term neuromonitoring, necessary during intensive care therapy. To evaluate quality and sensitivity of NIRS measurements compared to invasive ICP-, CPP- and regional brain tissue--pO2 (p(ti)O2) monitoring, 31 patients, suffering from severe brain injury due to subarachnoid hemorrhage or severe head injury, were studied. NIRS measurements were only possible in 80% (using the INVOS oximeter) and in 46% (using the CRITIKON monitor), while good data quality was obtained in 100% from ICP, CPP and p(ti)O2. Major reasons for the failure of NIRS measurements were: (1) a wet chamber between sensor and skin, (2) galea hematoma or (3) subdural air after craniotomy. Different tests were performed to compare the sensitivity of regular oxygen saturation (NIRS) with the sensitivity of invasively determined p(ti)O2. Only induced hyperoxia (FiO2 = 1.0) revealed a significant correlation between both parameters (r = 0.67, p < 0.01). Lower or no correlation was found after changing paCO2 and administration of mannitol. The high failure rate and the limited sensitivity does not make the clinical use of near-infrared spectroscopy suitable as a part of neuromonitoring after acute brain injury at the present time.

Adult↗