Hydrocephalus is a relevant neurosurgical pathology, both in children and in the ageing population. It comprises a wide set of ailments associated with alterations of the cerebrospinal fluid hydrodynamics and the bio-mechanical properties of the nervous central system structures. In many cases, these pathologies are characterised by an enlargement of the lateral ventricles of the brain (due to accumulation of fluid) and by the physiological and cognitive consequences of compression of adjacent structures, damages in surrounding tissue and other effects of increased intracranial pressure.
Treatment mostly relies on implanting subcutaneous shunt systems to drain cerebrospinal fluid from brain ventricles to a distal cavity. However, complications are frequent and the most common are obstructions of flow through implanted catheters and valves. They are difficult to anticipate and require immediate surgical removal because of risks of serious neurological damage and even death. Such complications have a deep social impact in the quality of life of patients, their families and caregivers, and a high economic cost. Early diagnosis and treatment of an obstructed catheter or shunt malfunction remains as a defying area and there is no preventive technology or protocol to avoid them.
This project presents the design and development of a hand-held device for the application of image-guided, focused ultrasound for preventive, non-invasive, easy-to-implement, and cost-effective acoustic cleaning of implanted shunts in patients of hydrocephalus. If successful, this procedure could be performed on a routine basis to any patient. This project explores the potential of mechanical and thermal effects of cavitation and acoustic streaming for removal of accumulated debris, clearing obstructions and improving cerebrospinal fluid flow through implanted catheters and
valves. This is a novel application of the underlying ideas of the acoustic (ultrasonic and megasonic) cleaners that are commonly used in many industrial applications to remove contaminants without damaging the surfaces of substrates. This approach is based on physical, optical, and neurosurgical tools that already exist and are commonly used in their corresponding applications.
Image guidance and monitoring is achieved by the combination of optical (visible and thermal infrared) and conventional medical ultrasound imaging. These technologies complement each other and their combination will allow for a fast and precise location of the shunt and catheters, located only a few millimetres under the skin (over the skull bone). Computational 3D simulation and an experimental proof-of-concept will be carried out in laboratory phantoms and in a cadaveric model head under physiological-like conditions (infections, temperature). Piezoelectric transducers generate the ultrasound waves to be concentrated at the target by electronic (phase) control.