Surgical Plan Solution for Deformity Correction Seoul National

Surgical Plan Solution for Deformity Correction Seoul National University Movement Research Lab. Seoul National University Bundang Hospital 2013. 4. 6 Jiwon Jeong

Motivation (1/2) � Find the best surgical plan and minimization of unexpected side effects � Focus on the surgery which cause transformation of bone geometry � Care about the complex side effects of single-stage multi-level surgery Personal Data (X-Ray) Automatic 3 D Reconstruction • Lower limb bone (Femur, Tibia) • 3 D mesh model Manual Simulation • By person • Using simulator Automatic Simulation • By simulator • Need policy Movement Research Lab. SNU Find Best Solution • Variables (position, angle, wedge, etc. ) Perform Surgery 1/8

Motivation (2/2) � What is an important criterion when developing the surgical plan? � Clinical measurements (neck-shaft angle, femoral version, shaft bowing etc. ) � Lower limb alignment (mechanical axis, anatomical axis, etc. ) [Clinical measurements] Movement Research Lab. SNU [Lower limb alignment] 2/8

Approach � Full Process � 3 D reconstruction of lower limb using X-ray images (2 biplanar X-ray images) � Find the feature points in lower limb using 3 D geometry model � Calculate the parameters which are related with lower limb posture � Find the best surgical plan (below is an example of FVDO) � Input : patient’s current posture (feature points and parameters pair) predefined ideal posture (parameters) � Output : wedge angle, cutting position, rotation angle and expected posture � Processing : minimization of error between patient’s posture and ideal posture Movement Research Lab. SNU 3/8

Process #1 � 3 D Reconstruction of lower limb using X-ray images � Input : 2 biplanar X-ray images � Output : 3 D geometry model of femur and tibia � Development approach � Femur : already done (be sure to check it is working accurately to abnormal bone) � Tibia : development approach is as same as femur reconstruction [Process of femur reconstruction] Movement Research Lab. SNU 4/8

Process #2 & #3 � Find the feature points of lower limb using 3 D geometry model � Using vertex level processing, find the feature points � Calculate the parameters which are related with lower limb posture � Using the feature points, calculate the axes, planes, and parameters Parameters Neck-shaft angle Femoral version Hip-knee-ankle angle Condylar-tibia angle Mechanical axis deviation [Lower limb feature points & axes example] Movement Research Lab. SNU [Parameters example] 5/8

Process #4 (1/2) � [FVDO] Movement Research Lab. SNU 6/8

Process #4 (2/2) � Movement Research Lab. SNU 7/8

Action Plan � Set the feature points and parameters � Define important parameters for surgical plan or lower limb posture � Define axes, planes, and points for calculation of parameters � Formulation � Tibia reconstruction � Make a training set for tibia reconstruction � Check the accuracy of femur reconstruction solution for an abnormal bone � Develop a tibia reconstruction Movement Research Lab. SNU 8/8

Thank you