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Dietmar Stolke

Publications and source records attributed to Dietmar Stolke.

14 recordsLinked to original sources
PubMed2003

Recurrent hemorrhage after initially complete occlusion of intracranial aneurysms.

Recurrent hemorrhage in the case of incompletely treated aneurysms is well known. The authors present a series of patients in whom rebleeding occurred in spite of totally occluded aneurysms. During a period of 12 years, 1170 patients with intracranial aneurysms were treated using either clipping (n=727) or coiling (n=443). In 11 of them, intracranial rebleeding occurred, in seven of whom routine post-treatment angiography revealed total aneurysm occlusion before the appearance of rehemorrhage. Further analysis focused on these seven patients. Their recurrent aneurysm ruptures happened with a mean latency of 9.5 months (range 21 h-48 months) from initial treatment. All aneurysms belonged to the anterior circulation. Three patients underwent primary clipping, and four experienced coiling first. The intracranial hemorrhages appeared mainly as intracerebral hematomas. The angiographically documented recurrent aneurysm configurations were caused by clip slippage (n=2), coil compaction (n=3), or coil migration/dislocation (n=1). In one case with primary surgery, clip slippage was possible but not confirmed by intraoperative view, because the patient died before therapeutic intervention. Two patients did not undergo therapy because of their poor clinical condition and died. Four of the remaining patients underwent clipping of the recurrent lesions, and one had recoiling. Final outcome was excellent/good in only two patients. The mainly poor outcome after rebleeding was caused by the high incidence of intracerebral hemorrhage.

Adult↗
PubMed2003

Intramedullary spinal cord cavernous malformations: clinical features and risk of hemorrhage.

The aim of this study was to review the natural history of symptomatic intramedullary spinal cord (IMSC) cavernous malformations in order to analyze the underlying mechanisms leading to symptoms and determine the potential risk of lesional hemorrhage. Between January 1990 and June 2001, ten consecutive patients with IMSC cavernous malformations were treated surgically in our institution. Age ranged from 17 to 73 years (mean 34.5). All patients became symptomatic due to one or more hemorrhages leading to neurological deficits of different severity, with a more aggressive course for upper cervical lesions. Pre- and postoperative patient condition was classified according to the Frankel scale. Four patients experienced one hemorrhage, four patients two, one patient three, and another one five repeated hemorrhages. The annual retrospective hemorrhage rate for symptomatic IMSC cavernous malformations was 4.5% per patient/year, with a prospective rehemorrhage risk of 66% per patient/year. The postoperative condition was improved in four patients and unchanged in six, and none grew worse. Detailed analysis of history and clinical course in all patients revealed an acute onset of symptoms with subsequent neurological deterioration after each bleeding episode. Based on the significant risk of rehemorrhage and the gratifying functional results, surgery is indicated for symptomatic IMSC cavernous malformations.

Adolescent↗
PubMed2003

Brain diffusion after single seizures.

PURPOSE: Diffusion-weighted magnetic resonance imaging (DWI) after focal status epilepticus has demonstrated focal alterations of the apparent diffusion coefficient (ADC) in the epileptogenic zone. We hypothesized that localized dynamic alterations of brain diffusion during the immediate postictal state will be detectable by serial DWI and correlate with the epileptogenic zone. METHODS: Nine adult patients (four men, five women) with medically intractable epilepsy were prospectively examined with a total of 25 DWI scans taken 2-210 min after a seizure. RESULTS: The interictal ADC was significantly (p < 0.05) elevated in the ictogenic hippocampus in all patients with temporal lobe epilepsy. The following postictal changes of the ADC were seen: (a) decreases by maximally 25-31%, which were most pronounced in the epileptogenic zone (n = 2); (b) generalized ADC changes after generalized seizures (n = 1) or prolonged complex partial seizures (n = 2); (c) no major changes after short-lived seizures or if the time to first DWI scan was >15 min or both (n = 3); and (d) widespread bilateral ADC increases after a flumazenil-induced seizure (n = 1). CONCLUSIONS: ADC changes seen during serial postictal DWI are complex and appear to reflect origin and spread of the preceding seizure. A delineation of the epileptogenic zone appears to be possible only in complex-partial seizures of >60 s duration that do not secondarily generalize.

Adult↗
PubMed2003

Visual evoked potentials for intraoperative neurophysiologic monitoring using total intravenous anesthesia.

Conflicting reports on the usefulness of intraoperative monitoring of visual function by means of visual evoked potentials (VEPs) initiated this study. In 32 patients without visual problems, VEPs were recorded to evaluate the reliability for intraoperative monitoring with total intravenous anesthesia. All patients underwent noncranial surgery. Using a standard technique, VEPs were recorded preoperatively in the awake patients and after induction of anesthesia during surgery. A total of 1436 intraoperative traces were recorded and analyzed. A minor prolongation of the P100 latency of 8% and a more pronounced attenuation of the P100-N145 amplitude of 60% were observed in the anesthetized patients. In most of the anesthetized patients, a stable recording of VEPs was not obtainable. In 4 patients (12.5%), clearly identifiable VEP peaks were detected in more than 90% of the traces recorded intraoperatively. In 88% of the patients, reproducible VEPs were obtained in less than 75% of the intraoperative traces only. We concluded that with standard recording techniques and total intravenous anesthesia, intraoperative VEP monitoring in surgically anesthetized patients is not reliable.

Adult↗
PubMed2003

Intraoperative measurement of cortical oxygen saturation and blood volume adjacent to cerebral arteriovenous malformations using near-infrared spectroscopy.

OBJECTIVE: Both cortical oxygen saturation (SaO(2)) and cortical blood volume (BV) are related to regional cerebral blood flow. Among a series of patients with cerebral arteriovenous malformations, we examined the problem of hyperemia after embolization/resection or resection with the intraoperative application of near-infrared spectroscopy. METHODS: Cortical SaO(2) and BV (intracapillary total hemoglobin concentrations) were measured, with near-infrared spectroscopy, in areas adjacent to the arteriovenous malformation for 20 patients, before and after resection. The absolute values for both parameters and postexcision/preexcision ratios (P-P ratios) were determined. Data were correlated with multiple clinical and preoperative angiographic parameters. RESULTS: Before resection, the mean SaO(2) was 49 +/- 16% and the mean BV was 12.65 +/- 7.41 mg/ml. After resection, SaO(2) increased for 17 of 20 patients and BV increased for 18 of 20 patients. The differences between pre- and postexcision values for both parameters were observed to be statistically significant (P < 0.01). The average P-P ratios were 1.5 +/- 0.4 for SaO(2) and 1.7 +/- 0.4 for BV. Correlation between the P-P ratios for the two parameters was good. The initial BV and the P-P ratios for both SaO(2) and BV were exclusively dependent on the extent of preoperative embolization. Postoperatively, two patients developed intracerebral hemorrhage or severe edema. Both demonstrated high P-P ratios for SaO(2) (2.3 and 2.1) and BV (1.6 and 2.1). CONCLUSION: Intraoperative near-infrared spectroscopy is able to detect the hyperemic status of adjacent cortex after arteriovenous malformation resection. However, staged therapy with embolization and surgery results in less hyperemia after resection. While two patients with hyperemic complications exhibited very large increases in SaO(2) and BV, we cannot refute the normal-perfusion pressure breakthrough theory.

Adolescent↗
PubMed2002

Transcortical or transcallosal approach to ventricle-associated lesions: a clinical study on the prognostic role of surgical approach.

Most entities in and around the anterior two-thirds of the supratentorial ventricles can be reached via transcortical or transcallosal approach. This study examined the effect of surgical approach on the postoperative neurological outcome. Thirty-eight patients with intra- and periventricular supratentorial lesions were operated on by either frontal transcortical or anterior transcallosal approach. Postoperative diencephalic damage occurred in 22% of patients in the transcortical group and in 36% in the transcallosal group; transient mutism was virtually equivalent in the two groups. Postoperative epilepsy (26%) and subdural fluid collections (30%) occurred only in the transcortical group. The incidence of postoperative hemiparesis was higher in the transcallosal group. There was a high correlation between postoperative Glasgow Outcome Score of 5 and preoperative severity of neurological disease but no correlation between postoperative Glasgow Outcome Score of 5 and location of the lesion or between postoperative clinical course and surgical approach. Surgical outcome of ventricle-associated lesions depends mainly on the severity of preoperative symptoms and not on surgical approach. Additionally, the incidence of postoperative seizures and subdural fluid collections after transcortical surgery is high.

Adolescent↗
PubMed2002

A multidisciplinary quality management system for the early treatment of severely injured patients: implementation and results in two trauma centers.

OBJECTIVE: The impact of a multidisciplinary quality management system (MQMS) on the early treatment of severely injured patients was tested. DESIGN AND SETTING: Prospective clinical study in two level 1 trauma centers. METHODS AND MATERIALS: MQMS comprised a protocol for documentation, 20 assessment criteria, and the judgement of data by a quality circle. After implementation in Munich (1st period, n=90; 2nd period, n=77) the validation took place in Essen (1st period, n=175; 2nd period, n=150). RESULTS: Improvements in diagnostics were shown by significant time savings in radiological diagnostics and before computed tomography in severe traumatic brain injury. In patients with hemorrhagic shock there was a reduction in time before transfusion (49 to 14 min in Munich; 31 to 22 min in Essen) and before emergency operation (74 to 43 min in Munich; 69 to 45 min in Essen). The time before craniotomy was reduced from 97 to 67 min in Munich. The incidence of delayed diagnosis of life-threatening lesions was diminished from 6% to 3% in Munich (not found in Essen). The TRISS technique showed a reduction in mortality in both hospitals in the second period (Munich: 15.4% TRISS vs. 9.1% observed mortality; Essen: 17.8% vs. 11.3%). CONCLUSIONS: MQMS improved early clinical treatment in severe injury with respect to therapeutic effectiveness and outcome. The effectiveness of the MQMS was shown at two different hospitals

Germany↗
PubMed2002

Observations on intraoperative somatosensory evoked potential (SEP) monitoring in the semi-sitting position.

BACKGROUND: Former case reports suggest that monitoring of median nerve somatosensory evoked potentials (M-SEP) is unreliable in patients operated in the semi-sitting position due to the occurrence of evoked potential changes unrelated to neurological damage. This study was designed to analyze these changes in greater detail and confirm that these changes are not caused by neurological damage. METHODS: M-SEP monitoring findings of 50 patients with surgery in the semi-sitting position were analyzed and compared with a group of 50 patients who underwent surgery in the supine position. M-SEP amplitudes and latencies at distinct steps of the monitoring procedure were used for further analysis. In 10 of the 50 semi-sitting patients, M-SEP were recorded additionally after surgery with the anesthetized patient in the supine position. RESULTS: Significant M-SEP changes occurred in the semi-sitting patients only. An amplitude loss of greater than 50% on at least one side was observed in 24 patients. The magnitude and the time course of the amplitude loss was considerably variable. A complete loss of the evoked potential was not observed in any case. In all 10 patients, M-SEP recovered completely when recorded in the supine position. CONCLUSIONS: In about half of the patients with M-SEP monitoring in the semi-sitting position, a significant amplitude loss occurs which is unrelated to neurological damage and presumably caused by subdural gas collections. There is no characteristic pattern of M-SEP changes which enables a differentiation of these 'artificial' alterations from true events. The only appropriate criterion to indicate an impending neurological damage in these patients seems to be a complete loss of the M-SEP potential.

Adolescent↗
PubMed2002

Early seizures following non-penetrating traumatic brain injury in adults: risk factors and clinical significance.

BACKGROUND: In the literature dissenting data are obtained about risk factors for early post-traumatic seizures and their impact on outcome. This study was conducted to obtain more information about the clinical significance of early seizures and their possible impact on the treatment of traumatic brain injury. METHODS AND RESULTS: A consecutive series of 1868 adult patients with head injury were analysed retrospectively. Demographic data of the patients, characteristics of the injury, and findings on CT scan were recorded. Risk factors for early post-traumatic seizures were identified using univariate statistics. A multivariate logistic regression was performed to look for interaction of different variables. The impact of early post-traumatic seizures on outcome was examined in an analogous way. Chronic alcohol abuse, subdural haematoma and brain contusion were identified as independent risk factors for early post-traumatic seizures. A significant association of early post-traumatic seizures with an unfavourable outcome was observed, but this effect was small compared to other variables. CONCLUSIONS: Early post-traumatic seizures appear to be an acute reaction of the brain to cortical damage with little independent impact on the management of head injury.

Adolescent↗
PubMed2002

The impact of neurophysiological intraoperative monitoring on surgical decisions: a critical analysis of 423 cases.

OBJECT: The aim of this observational clinical study was to analyze the impact of neurophysiological intraoperative monitoring (IOM) on the surgical procedure and to assess the benefits of such monitoring. METHODS: Data for 423 patients who underwent neurophysiological IOM with somatosensory evoked potentials and brainstem auditory evoked potentials during neurosurgical procedures were collected prospectively. The patients were classified into one of five groups according to the findings of IOM, the intervention following a monitoring alarm, and the patient's postoperative neurological condition. These groups were as follows: patients with true-positive findings with intervention (42 cases, 9.9%), those with true-positive findings without intervention (42 cases, 9.9%), those with false-positive findings (nine cases, 2.1%), those with false-negative findings (16 cases, 3.8%), and those with true-negative findings (314 cases, 74.2%). Different interventions followed an event identified with monitoring. These interventions were related to dissection in 17 cases, to perfusion pressure in 11, to a limitation of the surgical procedure in five, to vessel clipping in four, to vasospasm in three, and to retraction in one case. In one case the surgical procedure was abandoned. A critical analysis and cautious estimation of the interventions revealed that IOM was helpful in preventing a postoperative deficit in 5.2% of the monitored cases. CONCLUSIONS; For critical analysis of the benefits of IOM one must evaluate not only the findings of IOM and the patient's postoperative neurological condition but also the intraoperative findings and surgical interventions following a monitoring alarm. Evidence is presented that IOM is helpful in preventing a postoperative deficit.

Adolescent↗
PubMed2002

Complementary management of partially occluded aneurysms by using surgical or endovascular therapy.

OBJECT: The authors present a series of patients in whom partially occluded aneurysms were retreated using complementary surgical or endovascular therapy. METHODS: During a period of 18 months, 301 patients with intracranial aneurysms were treated using either clip application (171 patients) or endovascular embolization with Guglielmi Detachable Coils ([GDCs] 130 patients). Routine posttreatment angiography studies revealed residual aneurysms in 21 of these patients, nine of whom were retreated using an endovascular or surgical method, with a mean treatment latency of 1.2 months. Four patients underwent primary surgical clip application, whereas five patients experienced GDC packing first. Among patients in the surgical group, the residual aneurysm neck was small and total elimination of the aneurysm was achieved by packing in GDCs. In patients in the endovascular group the authors incompletely packed the aneurysm because of its wide neck or fusiform component in two patients, perforation of a very small aneurysm in one patient, and coil dislocation in another patient. Typical coil compaction occurred in one case. Complete clip application was achieved in all patients. There was no complication in any patient due to the second treatment modality. Final outcome was excellent or good in six and fair in three. CONCLUSIONS: Following clip application or endovascular embolization of intracranial aneurysms, the use of complementary surgical or endovascular management is successful and associated with low morbidity.

Adolescent↗
PubMed2002

Endovascular treatment of unruptured intracranial aneurysms.

BACKGROUND AND PURPOSE: Intracranial aneurysms are common, with an overall frequency ranging from 0.8% to 10%. Because prognosis after subarachnoid hemorrhage is still very poor, treatment of unruptured aneurysms, either neurosurgically or endovascularly, has been advocated. However, risk of rupture and subsequent subarachnoid hemorrhage needs to be considered against the risks of elective treatment. We analyzed the technical feasibility, safety, and efficacy of endovascular treatment of a consecutive series of unruptured cerebral aneurysms. METHODS: From July 1997 through December 2000, a total of 76 patients with 82 unruptured cerebral aneurysms were treated at our institution. Endovascular treatment was administered to 39 consecutive patients with a total of 42 unruptured cerebral aneurysms. Thirty-six aneurysms were treated with an endovascular technique; in six patients, the parent artery was occluded to eliminate aneurysmal perfusion. Aneurysms were located either in the anterior (n = 31) or posterior (n = 11) circulation. Eight patients had experienced previous subarachnoid hemorrhage from other aneurysms and were treated electively after complete rehabilitation. Ten patients had neurologic symptoms; in 21 patients, the aneurysm was an incidental finding. Eighteen aneurysms were small (0-5 mm), 11 were medium (6-10 mm), nine were large (11-25 mm), and four were giant (> 25 mm). Occlusion rate was categorized as complete (100%), subtotal (95-99%), and incomplete (< 95%) obliteration. RESULTS: Endovascular treatment was technically feasible for 38 of 42 aneurysms. Complete (100%) or nearly complete (95-99%) occlusion was achieved in 34 of 38 aneurysms. In four aneurysms of the internal carotid artery, only incomplete (< 95%) occlusion was achieved. All patients except one with mild neurologic deficits according to the Glasgow Outcome Scale and one with mild memory dysfunction but no focal neurologic deficit achieved good recovery, resulting in a morbidity rate of 4.8% and a mortality rate of 0%. CONCLUSION: Endovascular embolization of unruptured cerebral aneurysms is an effective therapeutic alternative to neurosurgical clipping and is associated with low morbidity and mortality rates. For the management of unruptured aneurysms, endovascular treatment should be considered.

Adult↗
PubMedDate not supplied

Treatment of wide-necked intracranial aneurysms with a self-expanding stent system: initial clinical experience.

BACKGROUND AND PURPOSE: Currently available stents for intracranial use usually are balloon-expandable coronary stents that carry the risk of damaging a dysplastic segment of the artery, with potential vessel rupture. We assessed the technical feasibility and efficacy of the combined application of a flexible, self-expanding neurovascular stent and detachable coils in the management of wide-necked intracranial aneurysms in humans. METHODS: Four consecutive patients with a wide-necked intracranial aneurysm were treated with a combined approach that consisted of delivery of a flexible self-expanding neurovascular stent through a microcather to cover the neck of the aneurysm and subsequent filling of the aneurysm with coils through the stent interstices. The aneurysms were located at the internal carotid artery (n=2) and the basilar tip encroaching the P1 segment (n=2). Previous attempts with conventional endosaccular coil packing alone failed in all cases. RESULTS: Stent placement in the desired position with complete or nearly complete occlusion of the aneurysms was feasible in all patients. In one patient, aneurysm perforation with the microcatheter occurred and necessitated ventricular drainage, which led to a large parenchymal and intraventricular hemorrhage because of the strong anticoagulation regimen. Six-month follow-up demonstrated no focal neurologic sequelae in any of the patients, except slight memory dysfunction in the patient with bleeding. CONCLUSION: Preliminary data demonstrate that this extremely flexible stent is technically easy to deploy and can be easily and safely maneuvered through severely tortuous vessels, enabling the treatment of intracranial wide-necked aneurysms. The combination of endovascular reconstruction of the parent vessel with use of a self-expanding stent followed by coil embolization offers a promising therapeutic alternative for wide-necked aneurysms not amenable to coil embolization alone. Although immediate angiographic results are promising, long-term angiographic and clinical follow-up is essential to determine permanent vessel patency and aneurysm occlusion rate.

Angiography, Digital Subtraction↗