Noninvasive assessment of the elastance and reserve capacity of the craniovertebral contents via flow velocity measurements in the straight sinus by TCD during body tilting test.

Invasive recording of intracranial pressure (ICP) changes during cerebrospinal fluid (CSF) infusion-drainage tests have been used to estimate elastance and reserve capacity of craniovertebral contents. The increase in ICP and its pulse-related oscillations lead to "cuff constriction" of cerebral veins. The purpose of this study is noninvasive assessment of elastance and reserve capacity of craniovertebral contents (RCCC) by measurement of flow velocity (FV) in the straight sinus by transcranial Doppler (TCD) during body tilt tests, which cause changes in ICP. The study was performed in 14 healthy volunteers (age 12-49 y, 6 men) and 32 patients with Intracranial Hypertension (IH) (Benign Intracranial Hypertension, n = 14; Brain Tumors, n = 18). The straight sinus was insonated through the occipital window during body tilt tests (BTT). Tilt table position was changed gradually from head up (+75 degrees) to head down (-45 degrees). It was established that systolic flow velocity and amplitude of FV pulsations (Amp) in horizontal position in patients is usually higher than in healthy volunteers. We found that reserve capacity of craniovertebral contents in patients with IH was usually exhausted. Elastance in patients was usually significantly higher than in healthy volunteers. Evaluation of cerebral venous circulation during body tilt tests clearly differs between the patients with IH and the healthy volunteers. The degree of this difference depends on the localization and character of the pathologic process.     

CO2 and indomethacin vasoreactivity in patients with head injury

Summary The purpose of this study was to compare the effect of hyper-ventilation and indomethacin on cerebral circulation, metabolism and pressures in patients with acute severe head injury in order to see if indomethacin may act supplementary to hyperventilation. Fourteen severely head injured patients entered the study. Intracranial pressure (ICP), mean arterial blood pressure (MABP) and cerebral perfusion pressure (CPP) were monitored continuously. Within the first four days after the trauma the CO₂ and indomethacin vasoreactivities were studied by measurements of cerebral blood flow (CBF) (Cerebrograph 10a, intravenous¹³³Xe technique) and arterio-venous difference of oxygen (AVdO₂). Ischaemia was evaluated from changes in CBF, saturation of oxygen in the jugular bulb (SvjO₂), lactate and lactate/oxygen index (LOI). Data are presented as medians and ranges, results are significant unless otherwise indicated. Before intervention ICP was well controlled (14.8 (9–24) mmHg) and basic CBF level was 39.1 (21.6–75.0) ml/100 g/min). The arterio-venous oxygen differences were generally decreased (AVdO₂ = 4.3 (1.8–8.1) ml/100 ml) indicating moderate luxury perfusion. Levels of CMRO₂ were decreased (1.54 (0.7–3.2) ml/100 g/min) as well.Duringhyperventilation (APaCO₂ = 0.88 (0.62–1.55) kPa) CBF decreased with 11.8 (–33.4–29.7) %/kPa and ICP decreased with 3.8 (0–10) mmHg. AVdO₂ increased 34.0 (4.0–139.2) %/kPa, MABP was unchanged, CMRO₂ and CPP increased (CPP = 3.9 (–10–20) mmHg). AVD (lactate) and LOI were unchanged. No correlations between CBF responses to hypocapnia and outcomes were observed.An i.v. bolus dose ofindomethacin (30 mg) decreased CBF 14.7 (–16.7–57.4) % and ICP decreased 4.3 (–1–17) mmHg. AVdO₂ increased 27.8 (–40.0–66.7)%, MABP (MABP = 4.9 (–2–21) mmHg) and CPP (CPP = 8.7 (3–29) mmHg) increased while CMRO₂ was unchanged. No changes in AVd (lactate) and LOI indicating cerebral ischaemia were found.Compared to hyperventilation (changes per 1 kPa, at PaCO₂ level = 4.05 kPa) the changes in MABP, CPP and CBF were significantly greater after indomethacin, while the changes in AVdO₂, ICP, SvjO₂, and LOI were of the same order of magnitude.Nocorrelation between relative reactivities to indomethacin and CO₂, evaluated from changes in CBF and AVdO₂, or between the decrease in ICP after the two procedures were found. Thus, some patients reacted to indomethacin but not to hyperventilation, and vice versa.These results suggest that indomethacin and hyperventilation might act independently, or in a complementary fashion in the treatment of patients with severe head injury.     

Benign intracranial hypertension vs. intracranial arteriovenous malformation: A possible CT dilemma

Summary A nine-year-old boy, presenting only with signs of increased ICP, underwent computerized tomography. This examination demonstrated no abnormalities in the precontrast scan. Following C. E., it showed scattered areas of blood-like density in both hemispheres, as well as a presumedly abnormal vessel in the left occipital region and dilated vein of Galen, sinus rectus, and tentorial veins. The presumptive diagnosis of left occipital AVM was not confirmed by angiography, which also ruled out obstructions of the intracranial sinuses.The possible mechanism responsible for this atypical CT picture is briefly discussed in the light of pertinent literature. It is suggested that careful consideration should be given to the indications for angiography in similar cases, in the presence of a hypervascular aspect of the postcontrast CT scan, particularly if a considerable amount of contrast medium has been used.     

Multiple intracranial aneurysms: A high risk condition

Summary There is still a relative silence in the literature on what policy should be followed in treating multiple aneurysms. The main risks are: bleeding of a formerly asymptomatic aneurysm during the haemodynamic tides of the peri-operative period; aneurysm(s) can be hidden on angiograms and tend to be overlooked easier in case of an already revealed aneursym; misjudgement of the ruptured one as a silent additional aneurysm, therefore left for second stage surgery.This paper, based on a material of 330 operations for multiple aneurysms, focuses on these problems. It advocates the one stage complete repair of all lesions using both options of bilateral pterional craniotomies or the contralateral approach. But it also describes those silent aneurysms which safely could be clipped later. Hazards and disadvantages concerning the more aggressive surgery proved to be less significant than the natural history of multiple aneurysms represents.Presented at the EANS Wintermeeting on High Risk Neurosurgery, Budapest, February 20–23, 1991.     

Analysis of intracranial pressure

Methods for the acquisition and analysis of intracranial pressure (ICP) signals are reviewed from clinical and technical perspectives. The clinical importance of ICP monitoring is presented, and methods for ICP transduction are briefly discussed. These methods include intraventricular catheters, subarachnoid screws, epidural techniques, and the new fiberoptic ICP measurement systems. Approaches to the visual analysis of the ICP waveform are presented, with special emphasis on the relationship between the ICP waveform and the arterial blood pressure signal. Methods of computer-based ICP analysis are also reviewed, including histogram and systems analysis methods. Methods to predict ICP pressure rises and to estimate intracranial compliance are also discussed. Finally, ICP monitoring is reviewed from the point of view of patient outcome. It is concluded that advanced ICP waveform analysis methods warrant further clinical evaluation to demonstrate their clinical usefulness.     

Mass lesions of the frontal lobes in acute head injuries. A comparison with temporal lesions

Summary Contusions and lacerations of the frontal lobes are very frequent; 43.4% in the whole series of traumatic brain mass lesions. Clinical, ICP, CT scan data and neuropathological findings in patients with such lesions are analysed and correlated. Moreover, the clinical features and the outcome of frontal masses undergoing surgery are also compared with similar lesions located in the temporal lobes.Frontal lesions cannot be differentiated on purely clinical grounds and the factors governing the outcome in both locations are the same. On the whole, surgical indications nowadays seem to be rather rare; only lesions behaving truly as expanding lesions with obvious intracranial hypertension benefiting from surgery.Brain contusion-laceration syndromes in general can no longer be considered separate entities. Neither should they be included in the miscellaneous group of traumatic intracranial mass lesions, since the pathophysiological significance of purely extracerebral effusions is entirely different.Traumatic contusions and lacerations and/or intracerebral haematomas, whether frontal or located elsewhere, should, instead, be considered in the context of head injuries of a different degree of gravity, as having collateral features which, on occasion, may call for surgical management.     

Treatment of vertebro-basilar aneurysms

Summary In continuation of investigations on classification and treatment of ICA-system aneurysms and on the classification of the vertebro-basilar-system aneurysms their treatment has been discussed. Based on this, classification has been improved and the preoperative topographic diagnosis and the choice of approach have been influenced. The operative management has been pioneered by C. G. Drake, who described the technique in detail on hand of his enormous experience with 469 aneurysms of the vertebro-basilar-system (13). The necessity of a normal aneurysm neurosurgeon treating such aneurysms requires certain modifications of indication, approach and dissection. In a personal statement based on 35 VB-aneurysms (6 per cent) the strategy of handling these aneurysms has been developed (45). Microsurgical technique is regarded absolutely necessary. Thetransoral transclival access to aneurysms of the lower clivus should be included in the approaches, similarly to the transsphenoidal operations. It facilitates the direct isolation in a very difficult region.Electrothermic dissection of the aneurysm diminishes the risk of rupture during the isolation of the sack and facilitates the isolation of the neck. The statistics of Drake provide full data for the prognosis of these aneurysms. It is to note that in the recent time the results reported from different centres became more and more similar. The embolization of large bulbous or spheric and giant aneurysms by inflatable balloon-technique possibly may replace some risky direct or indirect operations.

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Zusammenfassung In Fortsetzung unserer Untersuchungen über die mikrochirurgische Klassifikation und Behandlung der Aneurysmen des A. carotis interna-Systems, sowie die Klassifikation der Aneurysmen des Vertebro-Basilaris-Gebietes befaßt sich der Beitrag mit der Therapie letzterer. Die moderne Klassifikation und parallel dazu die präoperative angiographische Diagnostik haben die Wahl der Craniotomie und des direkten Zugangs zum Aneurysma unmittelbar beeinflußt. Die operative Behandlung ist im wesentlichen das Werk eines Mannes — Charles Drake — der die Technik anhamd seines großen Krankengutes von derzeit 469 Fällen im Detail beschrieben hat. Die Notwendigkeit für den normalen Aneurysma-Neurochirurgen, derartige Aneurysmen zu behandeln, erfordert nach meiner Überzeugung gewisse Modifikationen der Indikation, des Zuganges und der Präparation. In einer persönlichen Stellungnahme, die sich auf eine Erfahrung von 35 Aneurysmen des Vertebro-Basilaris-Gebietes stützt (6%), werden die Prinzipien des Vorgehens erläutert. Die mikrochirurgische Technik ist unerläßlich.Dertransorale transclivale Zugang sollte für bestimmte Aneurysmen der A. basilaris ebenso durchgeführt werden, wie der transsphenoidale Zugang für Hypophysenadenome selbstverständlich geworden ist. Er erleichtert die direkte Freilegung in dem sehr risikoreichen Gebiet von Brücke und Hirnnerven.Dieelektrothermische Dissektion verringert das Risiko der Ruptur während der Präparation und erleichtert die Isolierung des Aneurysmahalses.Drake's Statistik enthält alle Einzelheiten über die Prognose der verschiedenen Vertebro-Basilaris-Aneurysmen als Maßstab für das eigene Resultat. Erfahrungen der letzten Jahre aus verschiedenen Kliniken zeigen, daß die Ergebnisse sich mehr und mehr angleichen.DieEmbolisation großer bulböser und sphärischer Aneurysmen und der Riesenaneurysmen durch die Ballon-Technik erscheint geeignet, risikoreiche direkte oder indirekte Operationen zumindest teilweise zu ersetzen.

     

Combined endovascular therapy of ruptured aneurysms and cerebral vasospasm

We describe two patients with subarachnoid haemorrhage due to a ruptured intracranial aneurysm and severe symptomatic vasospasm. The aneurysm was occluded with detachable coils followed by intra-arterial infusion of papaverine to treat vasospasm as an one-stage procedure. There was significant resolution of the vasospasm. The long-term clinical outcome in one patient was excellent, the other still has minor deficits. Combined endovascular aneurysm therapy followed by intra-arterial spasmolysis with papaverine is a technically feasable therapeutic alternative in patients with symptomatic vasospasm. Received: 5 November 1999/Accepted: 12 July 2000     

Surgery of basilar aneurysms associated with unexpected rupture of an internal carotid artery aneurysm

During a surgery of basilar aneurysms via the trans-sylvian approach, we encountered an arterial bleeding caused by rupture of an internal carotid artery aneurysm that had been difficult to diagnose before surgery, as it was a small and brood-neck aneurysm and mimicked arteriosclerosis. In spite of several surgical procedures, the surgical path at the basilar aneurysms became narrow, and we had to abandon the clipping of the aneurysms. Consideration of radiological and intraoperative findings was made for this case, demonstrating a pitfall that neurosurgeons may encounter during surgery. Received: 16 December 1998 / Accepted: 26 May 1999