Heart surface motion estimation framework for robotic surgery employing meshless methods

Abstract

Abstract-A novel heart surface motion estimation framework for a robotic surgery on a stabilized beating heart is proposed. It includes an approach for the reconstruction and prediction of heart surface motion based on a novel physical model of the intervention area described by a distributedparameter system. Instead of conventional element methods, a meshless method is used for a spatial and temporal decomposition of this system. This leads to a finite-dimensional state-space form. Furthermore, the state of the resulting lumped-parameter system, which provides an approximation of the deflection and velocity of the heart surface, is dynamically estimated under consideration of uncertainties both occurring in the system and arising from noisy camera measurements. By using the estimation results, an accurate reconstruction of heart surface motion for the synchronisation of the surgical instruments is also achieved at occluded or non-measurement points.

Simultaneous state and parameter estimation for physics-based tracking of heart surface motion

“…For reducing the dimensionality of the heart model, we constrain the tracking to the intervention area. By assuming that the heart surface in this area behaves like a linear elastic physical body with isotropic material structure, the heart dynamics can be approximately characterized by a discrete system equation, or system model [3], [4], [7] …”

“…For an application in a robotic surgery system, a variety of tracking approaches exists in related work [1]- [4]. In contrast to other approaches, the physics-based tracking [3], [4] guarantees a physically correct prediction of the heart behavior.…”

“…In contrast to other approaches, the physics-based tracking [3], [4] guarantees a physically correct prediction of the heart behavior. This tracking is based on a physical heart model and thus, exploits additional background information about the physical characteristics of the heart.…”

“…Therefore, for beating heart operations, an adjustment of the parameters featured in the intraoperative physical model is necessary for reducing the gap between the predicted response of the model and the real heart behavior. Until now, a personalized heart model for physics-based tracking in a robotic surgery on a beating heart has not been proposed [3], [4]. The main challenge of an intraoperative parameter identification is that the state and parameter estimation leads to a high-dimensional nonlinear estimation problem.…”

Visual stabilization of beating heart motion by model-based transformation of image sequences

“…When prediction of the heart motion for the synchronization of surgical instruments is investigated [1]- [4], only few methods are proposed for the visual stabilization of the beating heart. In [5], the use of electrocardiogram-triggered strobed light for making the heart appear still to a surgeon is explored.…”