Contact

Principal Investigator Ren Hongliang
Phone 6601 2802
Fax 6872 3069
Principal Investigator Yeow Chen Hua (Raye)
Phone6601 3014
Principal Investigator Yu Haoyong
Phone6601 3014

Surgical Robotics

Statistical Humerus Implants and Associated Intramedullary Robotics

Project Goals

The sizes of current off-the-shelf humerus implants are unable to accommodate Asian patients since they are mainly produced for American and European populations according to locally collected data. By creating statistical humerus atlases based on Asian data, gender-specific and region-specific humeral implants can be developed by considering the characteristics of the statistical atlas constructed in order to improve stability of the fixation and avoid related complications. Besides, it is envisioned that the statistical atlas can serve as a critical reference for development and evaluation of robots in surgical procedures. Particularly, for the surgical and interventional procedures in the confined and rotated intramedullary space, the curvature and shape statistics of internal humerus canal is of great significance for the dedicatedly design of snake-like curvilinear tubular robot.
In this project, an efficient way has been demonstrated to construct statistical atlas by adopting an efficient alignment algorithm with improved efficiency and good accuracy. The constructed humerus atlas is then regarded as the reference for design of various humerus implants and development of snake-like concentric tube robots.

Approach

Statistical Atlas Construction: A three-step algorithm is adopted in statistical atlas construction, including segmentation, alignment and principal component analysis (PCA). Segmentation is to extract the desired surface mesh information of the humeri from the raw CT data and alignment is to align all the samples. The final step is to perform the principal component analysis of the shapes and represent the statistical model using principal components.

Creation and application of a statistical humerus atlas

Centerline Extraction for Intramedullary Robot Design: The Laplacian-Based Contraction Method is adopted to extract the centerline of the humerus atlas. The purpose is to explore the intramedullary structure of the humerus since the curvature and shape statistics of internal humerus canal is significant for the design of snake-like curvilinear tubular robot.

Centerline Extraction Process

Curvature Analysis for Design of Humerus Implants: The maximum principal curvature is depicted in the below Figure. The curvature analysis is to study the statistical surface curvature of the humerus atlas, in order to assist the design of humerus implants such as proximal and distal humerus locking plates, both used in orthopaedic trauma fixation.

Principal curvature of the statistical humerus atlas

Current Results

By adopting the novel atlas construction algorithm, the statistical humerus atlas is constructed as shown in the below figure, where the shape variation is along the first three principal components (PCs) and each row is generated by varying the shape with -3 to +3 standard deviations.

Statistical Humerus Atlas

The variation along the first principal component is shown here (click to view the animation). From -3std to +3std, the length of the humerus model is increased while the width is decreased.

Shape variation along the 1st principal component

Moreover, by analyzing the characteristics of the humerus atlas, the intramedullary continuum robot design and the proximal humerus locking plate are depicted in the following figures.

Design of intramedullary continuum robot based on the statistical humerus atlas
Proximal humerus locking plate