William A. Hanson

An image-directed robotic system for precise orthopaedic surgery

The authors have developed an image-directed robotic system to augment the performance of human surgeons in precise bone machining procedures in orthopaedic surgery, initially targeted at cementless total hip replacement surgery. The total system consists of an interactive CT-based presurgical planning component and a surgical system consisting of a robot, redundant motion monitoring, and man-machine interface components. In vitro experiments conducted with this system have demonstrated an order-of-magnitude improvement in implant fit and placement accuracy, compared to standard manual preparation techniques. The first generation system described in this paper was used in a successful veterinary clinical trial on 26 dogs needing hip replacement surgery. It was the basis for subsequent development of a second-generation system that is now in human clinical trials. >

Development of a surgical robot for cementless total hip arthroplasty.

The long-term success of cementless total hip arthroplasty (THA) may depend on bone ingrowth into the porous-fixation surfaces of the implant. The ingrowth process is facilitated when the surgeon achieves a satisfactory fit for the prosthesis. Clinically or roentgenographically visible failure and persistent thigh pain after cementless THA remain significant problems, both of which may be alleviated by more precise preparation of the femoral canal and selection of an appropriately sized prosthesis. The objective of this study was to obtain an exact fit for the prosthesis through the use of an image-directed surgical robot for femoral canal preparation.

A surgical robot for total hip replacement surgery

The authors describe a robotic surgical system that has been designed to create femoral cavities that are precisely shaped and positioned for implantation of uncemented prostheses. This robotics system creates cavities with a dimensional accuracy more than 50 times greater than broached cavities, exceeds the tolerances to which implants are manufactured, and does not produce gaps that prevent bone ingrowth. A canine study was undertaken to evaluate the prosthesis fit and placement achieved by employing a surgical robot to prepare the femur. This study compared the results achieved on 15 dogs undergoing total hip replacement with manual broaching techniques and 25 dogs undergoing robotically assisted surgery. Among the 25 dogs, which ranged in age from 2/sup 1///sub 2/ to 11 years, there were no deaths, no infections, and no intraoperative complications. Human applications of this technique are also considered.<<ETX>>

Orlhodock - An Image Driven Orthopaedic Surgical Planning System

The OrthoDock (Orthopaedic Docking) system allows a surgeon to interactively manipulate a graphic representation of a prosthetic in 3d image data in order to determine optimum selection and position. Precise position and orientation information, both relative and absolute, of the prosthesis in the tissue is determined by using integrated graphics and image processing. The system is the 3d image processing portion of the robotic surgery system known as RoboDoc 111.

Information Extraction From Multi-Modality Medical Imaging

Two information. extraction methods were applied to selected diagnostic medical images obtained from different imaging. modalities. Sample images consisted of magnetic resonance tomograms, transmission computed tomograms, and emission computed tomograms of patients with focal and generalized brain abnormalities. Color composite analysis applied to image pairs afforded a limited but potentially useful approach to enable rapid, objective. depiction of relative and absolute contribu-tions from dualmodality parameters. Cluster analysis applied to image pairs or triplets was computationally more demanding, but this approach afforded a method for objective classification of tissues that could be generalized. Technical problems arise from patient factors and machine factors. Patient factors include motion and positioning. Machine factors include resolution, orientation, format, registration and scaling.

Advances in Landsat Image Processing and Mapping

A procedure and system have been developed to interactively correct the geometry of image data, and merge the data with auxiliary graphical data. This system provides the following capabilities: 1. Correct the absolute and relative geometry of images. 2. Register two or more images to each other. 3. Register and overlay graphics data onto image data. 4. Change the geometry of the image and graphics data into any of twenty standard cartographic projections. 5. Provide an assessment of the accuracy of the geometric operation. The system provides for both manual selection of ground control points to establish the geometric correction parameters, and an automatic determination of mapping parameters from operator definition of the desired cartographic projection. Experiments have been conducted using a number of data sources, including Landsat Thematic Mapper data, geophysical gravity data, and digital line graph cartographic data.