Investigation of methods and materials for individually mouldable micro-stereotactic frame

• Applicants: Dr. Thomas Stephan Rau; Dr. Rolf Benedikt Salcher
• Subject Area: Otolaryngology, Phoniatrics and Audiology ; Mechanics
• Term: from 2019 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 433571394

The ongoing progress in all fields of surgery with continuously minimized invasiveness and with ever increasing accuracy requirements makes support of the surgeon through assistance systems increasingly indispensable. However, these systems are often large and expensive (such as surgical robots) or not sufficiently accurate (such as image-guided surgery systems). In addition, a relevant proportion of these interventions are characterized by a comparatively simple positioning task. For this purpose, miniaturized stereotactic frames could be appropriate. Within this interdisciplinary research project, a new concept for an individually mouldable instrument guide should be developed and evaluated systematically regarding accuracy and clinical handling. The overall objective is to enable the surgical staff to build the positioning aid directly in the operating room in a completely sterile process with intuitive and easy to learn manual steps for an immediately use for the particular patient. Doing so one should be able to get along without expensive and complex assistance devices in the future. Therefore, the limits of simplification are explored explicitly in this project – while keeping in mind highest accuracy requirements at the same time.At the beginning of the project suitable materials (modeling compounds, adhesives, etc.) will be selected and evaluated in basic experiments regarding achievable accuracy, intraoperative handling, and time for individual modeling and hardening. In addition, the causal linkage between design and accuracy will be investigated based on experimental results. In the further course of the project, these general insights are going to be applied for the development process of a novel micro-stereotactic frame with focus on maximum accuracy and the best possible simplicity. In final series of experiments, first using artificial skull phantoms, later human temporal bone specimens, the system will be metrologically evaluated in terms of fulfilling the stated requirements as well as rated clinically. This basic research and development is carried out using minimally invasive cochlear implantation surgery as a concrete example of a sophisticated surgical task in order to answer the question whether an assistance system characterized by simplicity and low level of technology is suitable for (selected) high-precision interventions. Additionally, these findings allow to conclude for which type of surgical interventions such micro-stereotactic frames are suitable – and for which unacceptable curtailments of safety limit simplification.

• DFG Programme: Research Grants