A System for Image Guided Computer Assisted Hip Surgery

Abstract

The term periacetabular osteotomy (PAO) refers to a surgical intervention that attempts to correct dysplasia of the hip joint, particularly malposition of the acetabular roof which causes insufficient coverage of the femoral head. The procedure, as performed in Bern, consists of several osteotomies of the pubis, ischium, and ilium and a re-orientation of the acetabular fragment with subsequent fixation. Various solutions exist for a preoperative determination of the optimal re-orientation of the acetabular cup (Barrance et al., 1995, Klaue et al., 1988, Murphy et al., 1990). However, it has not been possible to apply the planning parameters accurately during the operation. In addition, some of the osteotomies have to be performed without direct visual access to the surgical object due to limitations in the anatomy and exposure. Consequently, there is potential to endanger the hip joint and surrounding structures. It is hypothesized that a combination of accurate 3D-motion tracking together with image interactive navigation may establish a link between surgical planning and execution. To our knowledge, this study introduces for the first time an operation-system for PAO that bridges surgical planning, secure intraoperative navigation during the osteotomies, and exact guidance during the re-orientation in accordance with a preoperative planning.