Motivation

Surgical interventions on the brain are associated with high risks. They result mainly from damage to tissues (brain tissue, nerves, vessels) in the immediate vicinity of the surgical site or on the way to it. The development of intelligent neurosurgical instruments is therefore one of the goals of the Personalized Neurosurgery Network ZEREPRO and is intended to reduce the risks for patients.

Goal

In the HIST research project, three project partners are responsible for the development of a new type of "intelligent" brain spatula with an integrated sensor function for measuring the mechanical force exerted on the brain tissue and for signalling in the event of impending brain tissue damage

• Sensor technology for measuring the force effect - Micro-Hybrid Electronic GmbH
• Medical project support - University of Leipzig, Clinic and Polyclinic for Neurosurgery
• Data evaluation and visualization -Westsächsische Hochschule Zwickau, Faculty of Physical Engineering/Informatics

The sensor connected to the spatula is to collect data during the operation which, by means of evaluation and visualization, will be available to the surgeon for acute patient monitoring and subsequent surgical documentation.   

The data should be usable for quality assurance and risk minimization for future neurosurgical interventions. By coupling with the complementary follow-up project OXYPRO, the spatula system will be complemented with the measurement of blood oxygen saturation of the parenchyma. This will further minimize the risk of postoperative damage.

The intelligent brain spatula system offers much potential for positively influencing the quality and patient safety of future neurosurgical procedures on the brain.

Challenge

On the one hand, the focus of the project is on the adaptation of a suitable spatula design (thickness, shape, material, pliability, etc.) in the sense of the neurosurgeon. The sensor technology must provide the required measurement accuracy as well as be sufficiently robust for the measurement environment or the sterilization processes. For the measurement of force application by electronics, it must be ensured that no disturbance variables can influence the measurement and that reliable measurement data are transmitted to the evaluation unit.

The current challenge in research in the field of neurosurgery, however, is primarily the lack of data to make reliable statements and limit values about the effects of forces on brain tissue.

Solution

The development engineers Karl-Heinz Suphan and Matti Becker, as well as a total of 2 master students, have developed a simply ingenious solution for these high demands. The basis for this is the modular design of the system.

For the measurement of the force, an electronic circuit with 5 strain gauges was developed. So that the force applied by the brain spatula can be transferred directly to the strain gauges, these were applied to a foil which is only partially fixed.

The following figures show the structure of the developed system in the so-called validation setup.

One solution approach for the development of a corresponding database for the assessment of the effects of interoperative stress is to be developed with the follow-up project OXYpro. Through an additional measurement of blood oxygen saturation by a pulse oximetry sensor, which is also being developed by Micro-Hybrid, direct conclusions can be drawn about the supply situation of the brain tissue at certain pressures.