Development of a Prehospital Cranial Drill for Intracranial Pressure Sensor Placement

Abstract

Globally, approximately 20.8 million people sustain a traumatic brain injury (TBI) per year, and over half of these injuries result from traffic accidents or falls from a great height. The severity of a TBI is usually evaluated using the Glasgow Coma Scale (GCS), a GCS score of eight or lower indicates a severe TBI. Despite advances in care, the mortality rate remains high, with approximately 39% of patients with severe TBI dying within 30 days.

Patients with severe TBI are at high risk of developing elevated intracranial pressure (ICP) due to hemorrhage or cerebral edema as part of secondary brain injury. Increased ICP can lead to cerebral ischemia, brain herniation, and death; therefore, early recognition and treatment are essential. In the prehospital setting, management focuses on preventing secondary brain injury by elevating the head, administering hyperosmolar therapy, controlling ventilation, and regulating blood pressure. While ICP monitoring is standard practice in hospitals, there are no known technologies that can be used in a prehospital environment to create cranial access to facilitate ICP monitoring. If prehospital ICP monitoring were possible, it could enable targeted and individualized treatment, potentially patient outcomes.

Therefore, the goal of this thesis is to address the various steps involved in designing and manufacturing an in-house product based on the components required for these phases. The first step was to conduct market research. Initial market research revealed that there are no suitable invasive cranial access technologies for prehospital use. In a second market research, it was revealed that there are no usable non-invasive technologies in prehospital clinical practice to measure the ICP. In a third market research, several types of ICP sensors and monitors were found, each with their own advantages and disadvantages.Based on this research, it can be concluded that there is an absence of safe, rapid, and reliable methods for accessing the intracranial space or measuring ICP in the prehospital setting. Next, the necessary technical documentation was compiled in accordance with the Medical Device Regulation in order to develop a cranial access device. Next, a program of requirements was defined, and multiple design concepts were generated. Additionally, a test protocol was designed to evaluate developed prototypes, and proposals were formulated for qualitative and preclinical studies.

The first functional prototype was developed during this project. The design is based on the Arrow EZ-IO drill. This base holds a circular, 3D-printed design that can be adjusted in 1 mm increments to change the drilling depth from 0 to 6 mm. When evaluating this prototype, the skull model was in some areas thicker than the preset drilling depth of the device, meaning a complete breakthrough did not occur at those locations. There was minimal haptic feedback during the drilling process, meaning there was no clear tactile sensation when the drill bit passed through the skull layer. This information will be taken into account in future iterations of the prototype.

In conclusion, this project is an initial, exploratory step toward enabling prehospital ICP monitoring. It addresses the challenge of cranial access. The developed prototype lays the groundwork for future iterations and further evaluation. It also highlights the technical, clinical, and regulatory challenges that must be overcome before the technology can be safely implemented in clinical practice.