Patientenspezifische Planung für die Multi-Port Otobasischirurgie

Abstract

The current clinical approach for otologic surgery is largely invasive. Recently, a multi-port approach has been investigated in order to reduce the amount of traumatization. Here, three canals are drilled from the skull surface to the surgical site. Due to the minimal invasiveness of the new approach, the surgeon is not able to directly control the process visually anymore. Hence, a precise patient-specific planning based on image data is crucial. In my thesis, I focus on planning the course of the drill canals based on patient-specific models for this new multi-port approach. In order to generate those patient-specific models I first developed methods to segment the risk structures for otologic surgery in computed tomography data. The main challenges here are the small size of the structures, lacking contrast to neighboring structures as well as the varying shape and image intensities. To cope with these challenges, I adapted a generic model based approach - the Probabilistic Active Shape Model - to the risk structures for otologic surgery. I intensively evaluated the approach and showed that the segmentation accuracy is within the range of manual segmentation accuracy. Furthermore, I developed methods to automatically plan the course of the drill canals based on the extracted patient-specific models. The challenge here is that the multi-port approach is not yet in clinical practice and hence, there is a total lack of experience with this new procedure. As a first step, I developed a planning tool to compute the set of feasible drill canals that allows the manual choice of a combination of drill canals. Then, two clinicians conducted a feasibility analysis using this planning tool. I formalized the gathered expert data and derived a model for automatically determining the best combination of drill canals. The experiments show that the automatically computed drill canals are comparable to the manual choice of the clinicians. This enables the computer-assisted planning of the new multi-port strategy for otologic surgery