Karl Ungersböck

Evaluation of Cerebral Vasospasm after Early Surgical and Endovascular Treatment of Ruptured Intracranial Aneurysms

OBJECTIVE To document the influence of the treatment modality (early surgery versus early endovascular treatment) on measures of cerebral vasospasm in a nonrandomized series of 156 patients treated within 72 hours of aneurysmal subarachnoid hemorrhage. METHODS The following parameters were prospectively collected in a computerized data base and retrospectively analyzed for association with vasospasm-related ischemic infarctions: 1) Hunt and Hess (H&H) grade, 2) Fisher grade, 3) highest mean cerebral blood flow velocity (CBFVMAX) and maximum percent change in mean CBFV (%deltaCBFV) as recorded by transcranial Doppler ultrasound, 4) incidence of repeat subarachnoid hemorrhage, 5) incidence of delayed ischemic neurological deficits, 6) incidence of delayed ischemic infarctions, and 7) Glasgow Outcome Scale score. RESULTS Forty-one patients (26.3%) suffered ischemic infarctions. The ischemic infarction rate was correlated with higher H&H grade (P = 0.002), higher Fisher grade (P = 0.05), higher CBFVMAX (P < 0.001) and %deltaCBFV (P = 0.01), occurrence of repeat subarachnoid hemorrhage, occurrence of delayed ischemic neurological deficits, and endovascular treatment (P = 0.02). CONCLUSION The infarction rate was higher with endovascular treatment versus surgery (37.7 versus 21.6%), as a result of a skewed Fisher Grade 4 infarction pattern in the endovascular treatment group versus the surgery treatment group (66.7 versus 24.5%). We suspect that unremoved subarachnoid/intracerebral clots contributed to the higher infarction rate with endovascular treatment. When patients with Fisher Grade 4 and H&H Grade V were excluded from analysis, the difference in infarct incidence between the treatment groups no longer reached statistical significance (Fisher Grades 1-3, P = 0.49; H&H Grades I-IV, P = 0.96).

The keyhole concept in aneurysm surgery: results of the past 20 years.

BACKGROUND: Improvements in preoperative imaging and intraoperative visualization have led to a refinement in surgical techniques. OBJECTIVE: Report of a 20-year experience with application of the keyhole technique as a contribution to the ongoing debate on the impact of limited craniotomies in aneurysm surgery. METHODS: Over a 20-year period, 1000 consecutive patients with 1297 aneurysms were surgically treated in 1062 operations: 651 in the acute stage after SAH and 411 with unruptured aneurysms. The outcome was assessed with the modified Rankin scale and approach-related complications. RESULTS: The majority of the cases were treated by 4 different keyhole approaches: The supraorbital approach was used in 793 patients for 989 aneurysms, the subtemporal in 48 patients for 50 aneurysms, the interhemispheric in 46 patients for 51 aneurysms, and the retromastoidal in 55 patients for 55 aneurysms. In 120 patients, the classic pterional approach was applied to treat 152 aneurysms. The results of unruptured aneurysms were good (modified Rankin scale ≤ 2) in 96.52%. The complication rates of the keyhole approaches were less than in the pterional group, although the difference did not reach statistical significance. CONCLUSION: The overall outcome, rate of retreatment, and approach-related complications with keyhole approaches for the management of ruptured and unruptured aneurysms are comparable to recently published conventional surgical aneurysm series. In addition to the common benefits of limited-exposure approaches, this series demonstrates appropriate safety and applicability of the keyhole technique in aneurysm surgery.

Transcranial Doppler and cortical microcirculation at increased intracranial pressure and during the Cushing response: an experimental study on rabbits.

ABSTRACT: THE EFFECT OF increased intracranial pressure on the flow velocity of the basilar artery was measured with transcranial ultrasonic Doppler in New Zealand White rabbits under &agr;‐chloralose anesthesia and artificial respiration. Laser Doppler flowmetry served to study changes of the cortical microcirculation. The results confirm a high inverse correlation of the diastolic flow velocity, the pulsatility index, and the resistance index with the cerebral perfusion pressure (CPP). During acute intracranial hypertension, however, these parameters do not show a good correlation with the local cortical blood flow. The absence of a correlation was evident over a wide CPP range down to values of 35 mm Hg. Only at CPP values below this critical threshold is the microcirculation impaired. The threshold is reached at pulsatility index values of more than 2.0 and at resistance index values of more than 0.8. Therefore, transcranial Doppler indices permit the detection of critical reductions of microcirculatory blood flow. The Cushing reaction occurred with a constant time lag of 5.5 ± 0.7 seconds after the loss of CPP. The Cushing reaction did not establish systolic blood flow, which remained below the functional threshold, as concluded from the temporary loss of somatosensory evoked potentials.

Survival improvement in patients with glioblastoma multiforme during the last 20 years in a single tertiary-care center

ZusammenfassungStudienzielZiel der retrospektiven Analyse war es, die Überlebensdauer und einen eventuellen Fortschritt von 357 konsekutiven Patienten mit Gliob lastoma multiforme (GBM) innerhalb von 3 Gruppen aus unterschiedlichen Diagnose-Zeiträumen (Gruppe A: 1982–1984, B: 1994/1995; C: 1996–1998), die während der letzten 20 Jahre an unserem tertiärem Zentrum behandelt wurden, zu untersuchen.Patienten und MethodenPatienten der Gruppe A (n=100) wurden zwischen 1982 und 1984 diagnostiziert und dienten als historische Kontrolle. Patienten der Gruppe B (n=93) wurden 1994/1995 und Patienten der Gruppe C (n=164) zwischen 1996 und 1998 diagnostiziert.Die Überlebens-Analyse wurde durchgeführt in Bezug auf die drei Patientengruppen (A versus B versus C), in Bezug auf die applizierten Therapiemodalitäten nach neurochirurgischer Intervention (keine spezifische Therapie versus Radiotherapie versus kombinierte Radio-/Chemotherapie), in Bezug auf die unterschiedlichen first-line Chemotherapien, in Bezug auf Alter, Geschlecht und Tumorlokalisation. Die non-parametrische Kaplan-Meier Methode wurde angewandt. Ein p-Wert <0,05 wurde als statistisch signifikant angesehen.Patienten der Gruppen A und B erhielten Radio- und/oder Chemotherapie in einem unterschiedlichen Ausmaß (Radiotherapie: Gruppe A: 22%, Gruppe B: 62%; Chemotherapie: Gruppe A: 6%, Gruppe B: 33%). Die Chemotherapie wurde in beiden Gruppen nach Abschluss der Radiotherapie appliziert. In Gruppe C erhielten 96% der Patienten eine kombinierte Radio-/Chemotherapie innerhalb von 3 Wochen nach der neurochriurgischen Intervention.ErgbnisseDas mediane Überleben betrug in Gruppe A 5,2 Monate, in Gruppe B 5, 1 Monate und in Gruppe C 14,5 Monate (p<0,0001). Länger als 18 Monate lebten 9% der Patienten in Gruppe A, 10% der Patienten in Gruppe B und 25% der Patienten in Gruppe C (p<0,05).SchlussfolgerungDie Überlebenszeitverbesserung in Gruppe C ist auf die frühzeitige und kombineierte Applikation von Radio-/Chemotherapie zurückzuführen. Die Therapie wurde ambulant durchgeführt; dies wurde durch ein interdisziplinäres neuro-onkologisches Team ermöglicht. Die Nebenwirkungen waren mild und die Akzeptanz bei den Patienten hervorragend.SummaryMethodologyThe survival of 357 consecutive patients with newly diagnosed glioblastoma multiforme (GBM) in three treatment groups reflecting different time-periods of diagnosis (A: 1982–1984; B: 1994/1995; C: 1996–1998) was analysed to assess the impact and the potential improvement of changing treatment strategies in our tertiary-care center.Patients and methodsGroup A (n=100) included all consecutive patients diagnosed from 1982 to 1984 and served as the historical control. Group B (n=93) included all consecutive patients diagnosed in 1994/1995 and group C (n=164) those diagnosed from 1996 to 1998. Survival in the three treatment groups (A vs. B vs. C) was analysed according to treatment given after neurosurgical intervention (i.e. no specific therapy versus radiotherapy versus combined radio-/chemotherapy), and according to first-line chemotherapy, age (<40, 40–60, ≥60), sex, and tumor location (hemispheric versus bilateral or multifocal tumors, and tumors involving eloquent brain areas). Survival was analysed using Kaplan-Meier’s non-parametric method. A p-value <0.05 was considered statistically significant.ResultsPatients in groups A and B received radio-and/or chemotherapy to a varying extent (radiotherapy: group A: 22%, group B: 62%; chemotherapy: group A: 6%, group B: 33%). Chemotherapy was administered after termination of radiotherapy in both groups. In group C, 96% of patients received combined radio-/chemotherapy which was administered concomitantly and started within three weeks after surgery.Median survival was 5.2 months in group A, 5.1 months in group B and 14.5 months in C (p<0.0001). Nine patients in group A (9%), 9 in group B (10%) and 40 in group C (25%) survived more than 18 months (p<0.05).ConclusionsSurvival improvement in group C might be attributable to the early start of combined radio-/chemotherapy. Therapy was administered on a complete outpatient basis, enabled by a dedicated interdisciplinary neuro-oncologic team caring for group C. Toxicity was mild and patients’ acceptance excellent.

Evaluation of ICP by computerized bedside monitoring: Methods and clinical significance

The recording of intracranial pressure (ICP) is increasingly performed routinely in the hospital setting. Documentation of the pressure course over long time intervals has been performed, until recently, with paper tracings. Objective means of evaluation are lacking, however, for the quantification of pressure-dynamics. We have therefore tested several different statistical and graphical methods of evaluation to improve the efficacy of ICP monitoring. Calculations were done on epidural and transfontanel pressure monitoring. Analyses were performed both on-line and off-line. Graphical methods used included time-plot graphs, histograms, correlations analysis and pulse-amplitude/mean pressure diagrams (PA/Pm); statistical values calculated included mean, variance, standard deviation, coefficient of skewness, coefficient of kurtosis, coefficient of variation and the range. Data obtained from patients with normal intracranial pressure, CSF circulatory disturbances, head injuries, cerebrovascular disorders, and other illnesses allowed for the clear establishment of normal ICP limits, the rapid recognition of pathological pressure changes, the evaluation of therapeutic effects, and also an improvement in the comparability between new measurements and previous recordings. Simultaneously performed on-line evaluation of ICP recordings proved to be a practical means of monitoring both baseline values and therapeutic effectiveness.

MONITORING OF CORTICAL BLOOD FLOW : CLINICAL RELEVANCE OF EXPERIMENTAL LASER DOPPLER STUDIES

Continuous monitoring of cortical blood flow provides real time information of CBF-changes during neurosurgical operations and on the neurointensive care unit. Laser Doppler flowmetry is a continuous, noninvasive technique suitable for measurement of the cortical microcirculation. In a number of experimental studies we have analyzed the characteristics of this method for cortical blood flow monitoring. The high spatial resolution of laser Doppler flowmetry and the heterogeneity of the cortical microvascular network results in a scatter of flow values over a wide range depending on the site of measurement. Data collection from different spots and calculation of frequency histogram may serve as a measure of cortical blood flow. For clinical application instead of single fiber probes a multispot measurement approach will provide a reliable cortical blood flow monitoring. The use of continuous techniques will lead to a better understanding of cerebral hemodynamics under pathological conditions.