DICOM images facilitate 3D surgery planning

Italian researchers have released a new surgery planning system that uses DICOM images of the hip region to allow orthopedic surgeons to simulate the appropriate type, size, and position of hip prostheses.

The system, called Hip-Op, relies on CT data of the hip region to define patient anatomy in 3D.

"With Hip-Op, it is possible to digitally manipulate CT data to simulate the anatomical changes induced by the operation," said Dr. Riccardo Lattanzi of Laboratorio di Tecnologia Medica at the Istituti Ortopedici Rizzoli (IOR) in Bologna, where clinical Hip-Op tests have been performed for two years.

Hip-Op addresses the need for a preoperative planning tool for surgical procedures such as total hip replacement. I helps to determine size of the components, reducing complications and surgery time.

"Today, most surgeons superimpose transparent templates depicting implant shapes over x-ray film," Lattanzi said.

Problems with this method are the limited x-ray magnification and the 2D radiograph's inability to present views of rotated elements. Hip-Op yields full 3D representation of the patient's internal anatomy, based on CT data. While other orthopedic surgery planning programs based on CT or MRI data have been developed around the world, Hip-Op uses an original visualization method its developers call multimodal display.

"Multimodal display represents a new visualization paradigm for virtual medical objects," Lattanzi said. "This method allows users to rely on the primary sources of information with which they are already familiar, while simultaneously correlating information from other medical modalities and computer simulations."

Once Hip-Op launches and the DICOM CT data load from the hospital PACS, surgeons select the hip prosthesis they prefer from a library of conceptual and commercial components. They are then able to navigate the prosthesis within the patient body to the best anatomical position.

"Hip-Op may be useful not only to orthopedic surgeons but also to biomedical researchers, biomedical educators, and to medical devices designers," Lattanzi said.

In one case, special software based on Hip-Op was developed to perform 3D measurements directly on the DICOM image data. The tool was used to assess how growth and remodeling changed the morphology of a transplanted fibula used to reconstruct the proximal femur of a five-year-old child affected by Ewing's sarcoma, during the first three years of follow-up.

There is no charge for Hip-Op, which can be downloaded free from http://www.tecno.ior.it .