Dissertation Defense of Nicolas Padoy

Title: Workflow and Activity Modeling for Monitoring Surgical Procedures

Abstract:

The department of surgery is the core unit of the patient care system within a hospital. Due to continuous technical and medical developments, such departments are equipped with increasingly high-tech surgery rooms. This provides higher benefits for patient treatment, but also increases the complexity of the procedures' workflow. This also induces the presence of multiple electronic systems providing rich and various information about the surgical processes. The focus of this work is the development of statistical methods that permit the modeling and monitoring of surgical processes, based on signals available in the surgery room. These methods combine low-level signals with high-level information, and can be used to detect events and trigger pre-defined actions. A main application is the development of context-aware surgery rooms, providing adaptive user interfaces, better synchronization within the surgery department and automatic documentation. We introduce and formalize the problem of recognizing phases within a workflow, using a representation of interventions in terms of multidimensional time-series formed by synchronized signals acquired over time. We then propose methods for the modeling, off-line segmentation and on-line recognition of surgical phases. The main method, a variant of hidden Markov models augmented by phase probability variables, is demonstrated on two medical applications. The first one is the monitoring of endoscopic interventions, using cholecystectomy as illustrative surgery. Phases are recognized using signals indicating tool usage and recorded from real procedures. The second application is the monitoring of a generic surgery room workflow. In this case, phase recognition is performed by using 4D information from surgeries performed in a mock-up operating room in presence of a multi-view reconstruction system.

Advisers: Dr. Marie-Odile Berger (INRIA, Nancy), Dr. Nassir Navab (TUM, Munich)

Date: Wednesday 14th April 2010

Time: 2:30pm Duration: presentation (40mn) + questions asked by the committee

Location: Room 03.13.010 Technische Universität München Fakultät für Informatik / I16 Boltzmannstraße 3 85748 Garching bei München Germany