Closing the Calibration Loop: An Inside-out-tracking Paradigm for Augmented Reality in Orthopedic Surgery

TL;DR

This paper introduces an AR system with inside-out tracking for orthopedic surgery, enabling real-time visualization and improved navigation by closing the calibration loop between the patient, equipment, and surgeon.

Contribution

It presents a novel marker-less, dynamic inside-out tracking method using SLAM for AR in surgery, enhancing accuracy and usability over existing approaches.

Findings

Achieved low calibration and registration errors.

Enabled in situ visualization of 3D medical data.

Improved surgical guidance with 'bull's eye' view.

Abstract

In percutaneous orthopedic interventions the surgeon attempts to reduce and fixate fractures in bony structures. The complexity of these interventions arises when the surgeon performs the challenging task of navigating surgical tools percutaneously only under the guidance of 2D interventional X-ray imaging. Moreover, the intra-operatively acquired data is only visualized indirectly on external displays. In this work, we propose a flexible Augmented Reality (AR) paradigm using optical see-through head mounted displays. The key technical contribution of this work includes the marker-less and dynamic tracking concept which closes the calibration loop between patient, C-arm and the surgeon. This calibration is enabled using Simultaneous Localization and Mapping of the environment of the operating theater. In return, the proposed solution provides in situ visualization of pre- and intra-operative 3D medical data directly at the surgical site. We demonstrate pre-clinical evaluation of a prototype system, and report errors for calibration and target registration. Finally, we demonstrate the usefulness of the proposed inside-out tracking system in achieving "bull's eye" view for C-arm-guided punctures. This AR solution provides an intuitive visualization of the anatomy and can simplify the hand-eye coordination for the orthopedic surgeon.