Article
Visualisation of cisternal flow patterns after subarachnoid haemorrhage in a silicon rubber model and improving mobilisation of mock blood clot by means of external motion (head-shaking method)
Visualisation der zisternalen Flusseigenschaften nach Subarachnoidalblutung in einem Silikon-Modell und Messung des Einflusses nach externaler Bewegung (head-shaking method)
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Authors
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D. Hänggi
- Neurochirurgische Klinik, Heinrich-Heine-Universität, Düsseldorf
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M. Stock
- Labor für Biofluidmechanik, Fakultät 05, Hochschule für angewandte Wissenschaften, München
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J. Galdeano
- Labor für Biofluidmechanik, Klinik für Herz- und Gefäßchirurgie, Charité - Universitätsmedizin Berlin, Berlin
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K. Affeld
- Labor für Biofluidmechanik, Klinik für Herz- und Gefäßchirurgie, Charité - Universitätsmedizin Berlin, Berlin
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H.-J. Steiger
- Neurochirurgische Klinik, Heinrich-Heine-Universität, Düsseldorf
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D. Liepsch
- Labor für Biofluidmechanik, Fakultät 05, Hochschule für angewandte Wissenschaften, München
| Published: | April 11, 2007 |
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Outline
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Objective: Cerebral vasospasm remains the major complication after subarachnoid haemorrhage (SAH). Recent clinical publications suggested that head-shaking might attenuate cerebral vasospasm after SAH due to facilitated wash-out and therefore increased clot clearance rate. The goal of this study was to construct an in vitro subarachnoid haemorrhage model, to visualise the flow dynamics after induced SAH and to analyse the clot clearance rate in relation to externally applied motion.
Methods: We constructed a silicon rubber model of the cranial subarachnoid space of a healthy volunteer. This model was based on digital data of a thin layer CISS-MRT sequence. The model was connected to flow simulator and perfused with physiological pulsatile flow rates. First, basic flow patterns of artificial CSF were visualised by adding tracer particles (silver-coated hollow glass spheres (S-HGS) mean particle size of 15 µm) and using a video camera. In a second step SAH was simulated by adding a bulk load of particles. Flow patterns were compared with the base line flow pattern and mobilisation rate of the particle mass was defined. In a third step the model was moved with a rotational pattern (head-shaking simulation) and the influence on CSF flow and clearance rate were visualised and analysed.
Results: Flow patterns in the basal cisterns of the model could be qualitatively defined with the particle tracing method. Particle deposits could imitate some aspects of subarachnoid clots, i. e. flow dependent and delayed mobilisation. The application of a rotational motion pattern caused deformations of subarachnoid fluid flow and accelerated mobilisation of particle deposits in a rate and amplitude dependent fashion.
Conclusions: For the first time, experimental fluid dynamics was applied to cisternal flow in the context of subarachnoid haemorrhage. The set-up allowed defining basic cisternal flow patterns and the influence of flow and pulse rates, and external motion on mobilisation of intracisternal particle deposits. In general external motion accelerated clearance rate in an intensity dependent way.
