Nobuhiko Sugano “CAOS in THA”

Abstract

Various systems of computer-assisted orthopaedic surgery (CAOS) for total hip arthroplasty (THA) have been developed since the early 1990’s. These included computer assisted preoperative planning, robotic devices, navigation, and patient specific surgical templates. The first clinically applied system was an active robotic system (ROBODOC) which performed femoral implant cavity preparation as programmed preoperatively. Several reports on cementless THA with ROBODOC showed better stem alignment and less variance in limb-length inequality on radiographic evaluation, less incidence of pulmonary embolic events trans-esophageal cardio-echogram, and less stress shielding on DEXA analysis than conventional manual methods. On the other hand, some studies raise issues with active systems including a steep learning curve, muscle and nerve damage, and technical complications such as a procedure stop due to a bone motion during cutting requiring re-registration and registration failure. Semi-active robotic systems such as Acrobot and Rio were developed for ease of surgeon acceptance. The drill bit at the tip of the robotic arm is moved by a surgeon’s hand, but it does not move outside of a milling path boundary which is defined according to 3D-image-based preoperative planning.

Thanks to advances in 3D sensor technology, navigation systems were developed. Navigation is a passive system which does not perform any actions on patients. It only provides information and guidance to the surgeon who still uses conventional tools to perform the surgery. There are three types of navigation; CT-based navigation, imageless navigation, and fluoro-navigation. CT-based navigation is the most accurate, but the preoperative planning on CT images takes time that increases cost and radiation exposure. Imageless navigation does not use CT images, but its accuracy depends on the technique of landmark pointing and it does not take into account the individual uniqueness of anatomy. Fluoroscopic navigation is good for trauma and spine surgeries, but its benefits are limited in hip and knee reconstruction surgeries. Several studies have shown that cup alignment with navigation is more precise than conventional mechanical instruments, and that it is useful for optimizing limb length, range of motion, and stability. Recently, patient specific templates based on CT images have attracted attention and some early reports on cup placement and resurfacing showed improved accuracy of the procedures. These various CAOS systems have pros and cons. Nonetheless, CAOS is a useful tool to help surgeons perform accurately what surgeons want to do in order to better achieve their clinical objectives. Thus, it is important that the surgeon fully understands what he or she should be trying to achieve in THA for each patient.

Bio

Dr Nobuhiko Sugano received MD (1985) and PhD (1994) from Osaka University Graduate School of Medicine in Japan. In 1995 he was invited to Baylor College of Medicine in Houston, Texas, USA where he actively worked on three dimensional morphologic analysis of hip joint as Assistant Professor with Prof Philip C Noble. Those works were employed in design of hip joint implants for Japanese patients. In 2002, he received Otto-AuFranc award from the Hip Society for the research. Those computer research works also leaded him to play the role of leading orthopaedic surgeon in the area of computer-aided surgery from 1997. He developed a CT-based navigation system with his colleagues at Osaka University, and its clinical trial started in 1998. He also conducted several clinical studies using ROBODOC. His main interest in this area is robotics, navigation and postoperative motion analysis for arthroplasty. He received Maurice E. Müller Award for Excellence in Computer Assisted Surgery in 2011. He is currently a professor of Department of Orthopaedic Medical Engineering in Osaka University Graduate School of Medicine and Osaka University Hospital.

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Yoshinobu Sato: “Automated musculoskeletal segmentation and THA planning from CT images”

Bio

Yoshinobu Sato received his B.S., M.S. and Ph.D degrees in Information and Computer Sciences from Osaka University, Japan in 1982, 1984, 1988 respectively. From 1988 to 1992, he was a Research Engineer at the NTT Human Interface Laboratories. In 1992, he joined the Division of Functional Diagnostic Imaging of Osaka University Medical School. From 1996 to 1997, he was a Research Fellow in the Surgical Planning Laboratory, Harvard Medical School and Brigham and Women’s Hospital. From 1999 to 2014, He was an Associate Professor at Osaka University Graduate School of Medicine. From 2014, he is a Professor of Information Science at Nara Institute of Science and Technology (NAIST), Japan. His research interests include medical image analysis, computer assisted surgery, and computational anatomy. Dr. Sato was Program Chair of MICCAI 2013. He is a member of IEEE, MICCAI, and CAOS-International, and an editorial board member of Medical Image Analysis journal and International Journal of Computer Assisted Radiology and Surgery.