title: Projective invariant biplanar registration of a compact modular orthopaedic robot.
abstract: This paper presents a compact orthopedic robot designed with modular concept. The layout of the modular configuration is adaptive to various conditions such as surgical workspace and targeting path. A biplanar algorithm is adopted for the mapping from the fluoroscopic image to the robot, while the former affine based method is satisfactory only when the projection rays are basically perpendicular to the reference coordinate planes. This paper introduces the area cross-ratio as a projective invariant to improve the registration accuracy for non-orthogonal orientations, so that the robotic system could be applied to more orthopedic procedures under various C-Arm orientation conditions. The system configurations for femoral neck screw and sacroiliac screw fixation are presented. The accuracy of the robotic system and its efficacy for the two typical applications are validated by experiments.
authors.affiliation: School of Computer Science and Engineering, Beihang University, Beijing, China.
authors.forename: Sheng
authors.initials: S
authors.lastname: Luan
authors.forename: Lei
authors.initials: L
authors.lastname: Sun
authors.forename: Lei
authors.initials: L
authors.lastname: Hu
authors.forename: Aimin
authors.initials: A
authors.lastname: Hao
authors.forename: Changsheng
authors.initials: C
authors.lastname: Li
authors.forename: Peifu
authors.initials: P
authors.lastname: Tang
authors.forename: Lihai
authors.initials: L
authors.lastname: Zhang
authors.forename: Hailong
authors.initials: H
authors.lastname: Du
mesh_terms: D000465:Algorithms; D001858:Bone Nails; D001863:Bone Screws; D002138:Calibration; D004867:Equipment Design; D005272:Femur Neck / Q000473:pathology; D005471:Fluoroscopy; D005594:Fracture Fixation, Intramedullary / Q000295:instrumentation* / Q000379:methods; D006801:Humans; D019637:Orthopedic Procedures / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D012371:Robotics; D012446:Sacroiliac Joint / Q000473:pathology; D025321:Surgery, Computer-Assisted / Q000295:instrumentation* / Q000379:methods
keywords: Medical robotics; modular design; projective invariant