Design and clinical evaluation of an image-guided surgical microscope with an integrated tracking system

A new image-guided microscope system using augmented reality image overlays has been developed. With this system, CT cut-views and segmented objects such as tumors that have been previously extracted from preoperative tomographic images can be directly displayed as augmented reality overlays on the microscope image. The novelty of this design stems from the inclusion of a precise mini-tracker directly on the microscope. This device, which is rigidly mounted to the microscope, is used to track the movements of surgical tools and the patient. In addition to an accuracy gain, this setup offers improved ergonomics since it is much easier for the surgeon to keep an unobstructed line of sight to tracked objects. We describe the components of the system: microscope calibration, image registration, tracker assembly and registration, tool tracking, and augmented reality display. The accuracy of the system has been measured by validation on plastic skulls and cadaver heads, obtaining an overlay error of 0.7mm. In addition, a numerical simulation of the system has been done in order to complement the accuracy study, showing that the integration of the tracker onto the microscope could lead to an improvement of the accuracy to the order of 0.5mm. Finally, we describe our clinical experience using the system in the operation room, where three operations have been performed to dat

In-vitro validation of a device measuring the tibio-femoral contact forces and moments for efficient assistance during ligament balancing in total knee arthroplasty

Ligament balancing in total knee arthroplasty is believed to have an important influence on the joint stability and prosthesis lifetime. In order to provide quantitative information and assistance during the ligament balancing phase, a device that intraoperatively measures knee joint forces and moments has been developed

In-vitro evaluation of a force-sensing device for ligament balancing in TKA

Component loosening and instability are common causes of dysfunction after Total Knee Arthroplasty (TKA) and it is generally assumed that such complications are due to tibio-femoral misalignment or ligamentous imbalance. During the surgery, the ligamentous force balance is currently qualitatively assessed by the surgeon through manual trial movements of the limb. In order to improve this procedure, we developed a force-sensing device to intraoperatively measure knee joint forces and moments. The aim of this device is twofold: a) using tibio-femoral forces and moments make quantifiable measurements of what surgeons describe as a balanced knee joint b) help surgeons during TKA to reach this balance state

Surgical navigation system

The invention relates to a surgical navigation system, comprising a microscope to which a 3D measuring apparatus is rigidly fixed, for localising objects within the field of operation. Markers are fixed to the objects the position of which is desirable to know, for example, the patient or surgical instruments, which are themselves connected to the measuring system. The change in coordinates between the measuring system and the microscope is fixed as the two devices are rigidly connected. Also, knowing the position of the markers relating to the measuring system, it is possible to calculate the change in coordinates between the markers and the image from the microscope. When the markers are recorded, in other words when the relationship between the real objects and the virtual objects is determined, the information can then be used as a navigational instrument and/or for enhanced reality. A typical application for enhanced reality is the superimposition of a 3D anatomical model of the patient on the microscope image, generated from a pre-operative scan of the patient