Mitigating failures and enhancing reliability of a canine ventricular shunt through robust multi-objective design method.

Hydrocephalus is a condition that can result in increased intracranial pressure due to the excessive accumulation of cerebrospinal fluid (CSF) or blockage of the outflow of CSF at the level of the third or fourth ventricle. The basic treatment for hydrocephalus is CSF drainage by inserting a surgical tube (shunt) into the ventricle. Despite many new shunt design solutions, shunt failures are a regular occurrence, further complicating treatment. To address this problem, we demonstrate the effectiveness of a robust multi-objective design method to optimize the design of a canine ventricular shunt. In this paper, we investigate the causes of shunt failures and utilize this knowledge to obtain design solutions that minimize the risk of failures in shunts. Key shunt performance parameters that influence shunt failures, such as flow velocity, pressure difference and shear stress, are identified and their relationships with shunt geometry are established. A multi-objective robust design problem is formulated to identify shunt designs that are relatively insensitive to uncertainties while satisfying multiple, conflicting design goals. By using a multi-objective robust formulation, (1) the risk of shunt failures is minimized by designing against multiple criteria that govern failures in shunt, and (2) the reliability of the undertaken design decisions is improved by identifying and managing uncertainties. The method presented is demonstrated using a canine shunt design. However, it is generic enough to be applied to the design of human ventricular shunts and similar biomedical devices.