Accuracy of an image-guided navigation system for pelvic surgery based on a multimodality registration object: a cadaver study.

Accurate registration of external landmarks is often required for computer-aided surgery. In the study reported here, we investigated the influence of a new externally fixated multimodality registration object (MRO) on the accuracy of an image-guided navigation system in a human cadaver pelvis. With the MRO placed on the ipsilateral anterior superior iliac spine (ASIS), 14 of 17 target points showed a mean deviation (1.1 mm) that was significantly lower than that registered with the MRO on the contralateral ASIS (2.5 mm). In addition, the distance of target points from the MRO and the deviation of target points were highly correlated. This MRO provides a feasible means for achieving improved registration in computer-aided surgery of the pelvis.