title: An Electromechanical Hydrocephalus Shunting System
Creators: name: Salih, O
Publisher: name: Liverpool John Moores University
Year: 2024

description: Hydrocephalus (HC) is a disease that occurs as a result of the increased cerebrospinal fluid (CSF) amount in the brain. The disease is managed by what is termed a shunt, which is a medical tool that is implanted surgically to divert CSF from the brain. As a result of their passive design nature, these shunts have multiple fundamental shortcomings and failures, causing considerable inconvenience and risks to the patient. The aim of this research is to design an agile and active HC management framework that is capable of addressing the shortcomings and failures of the currently used CSF shunts in the most convenient manner for the patient and to advance research regarding hydrocephalus management. Thus, this work proposes an active patient shunting and monitoring system layout for CSF drainage and patient follow-up. The system layout is designed so that each component is put in place to address the shortcomings of passive shunts. To achieve this, the shunting system proposed is a closed-loop system that consists of multiple sensory inputs for patient monitoring and CSF drainage control to keep the patient's intracranial pressure (ICP) at the required level. As various studies looked at new shunting systems concepts from the perspective of algorithms, the novelty and focus of this work is on the hardware side of the active shunting system. The proposed electromechanical shunting system's core hardware component is the valve it uses. Hence, this study provides a detailed design and methodology of a novel electromechanical valve. This is where the main gap of knowledge has been identified, as current research is still focused on passive valves. Mathematical modelling was conducted during the valve conceptualisation process. The results showcased that although current passive valves cannot address hydrostatic pressure effects, they are three times more active than automated valves and can generate a smoother pressure profile. Based on this, a novel concept of a hybrid electromechanical valve that utilises an ultrasonic element attached to a ball-in-cone system is proposed. The design methodology of the valve components included the use of computer modelling, where forces inside the flow compartment were obtained using computational fluid dynamics (CFD). Spring sizing and ultrasonic element design were carried out using finite element analysis (FEA). The designed valve operates under a 3.5 V high-frequency current, has a 10 – 20 mmHg range, and can drain CSF up to 300 mL/h. The proposed electromechanical valve showcased that it possesses multiple features that the current passive valves do not. This includes malfunction detection, event recognitions, and wireless pressure settings revisions. Its main drawback is its lack of blockage management. A wearable device was developed to diagnose and monitor normal pressure hydrocephalus (NPH) patients, as NPH is not associated with increased intracranial pressure (ICP). The device consists of a 3-axis ± 3.7 g accelerometer to measure gait patterns, an HC-05 bluetooth module, a 3.7 V battery, and an Attiny85 microcontroller. A functionality test was carried out on the device by conducting a vibrational analysis assessment using a miniature shaker. After calibration, the device proved that it could supply accurate acceleration data on all three axes. The device range, sensitivity, placement, and multi-axis use show that it may produce more accurate results compared to those used in the literature.