Enhanced graphic features for computer assisted surgery system

Abstract

A computer assisted surgery system with is enhanced graphics features is described for assisting a surgeon in orthopaedic procedures. A system is described for use in inserting multiple guide pins in hip fracture surgery using a single bore drill guide that has a graphical representation comprising its real trajectory and one or more virtual trajectories, the virtual trajectories representing potential positions of other guide pins to be placed during the procedure. Additionally, representations of inserted guide pins and virtual trajectories may be retained on the display at their inserted positions for use in aligning subsequent guide pins. A system is also described for orientation of an acetabular cup in a total hip replacement surgery. During cup insertion, the surgeon is provided with information regarding the orientation of the cup with respect to a pelvic reference frame that is based on accepted pelvic landmarks. The positions of each landmark is calculated by the system when a probe with a virtual tip, separate from its physical tip, is overlaid on the landmark in roughly orthogonal images of the pelvis.

Description

RELATED APPLICATIONS [0001] This application is a divisional of U.S. application Ser. No. 09 / 683,104, filed Nov. 19, 2001, entitled “Enhanced Graphic Features For Computer Assisted Surgery,” which is hereby expressly incorporated herein in its entirety including the specification, claims, drawings and abstract.BACKGROUND OF THE INVENTION [0002] This invention relates to a computer assisted surgery system with enhanced graphics capabilities for use in inserting multiple screws into a hip fracture and orienting a total hip acetabular component. [0003] Fractures of the femoral neck, one kind of hip fracture, are a common injury of the elderly with over 150,000 such fractures occurring annually. The currently accepted treatment for mildly displaced femoral neck fractures is surgical fixation. In the procedure, three cannulated screws are inserted in the hip, from the lateral aspect of the femur, across the fracture site and into the femoral head. The initial step is the placement of thr...

AI Technical Summary

Benefits of technology

"The present invention is a computer assisted surgery system that uses virtual and real representations of instruments and anatomical landmarks to improve the accuracy and efficiency of surgical procedures. The system includes a computer, a localizing device, and a display monitor. It can assist surgeons in positioning multiple guide pins for hip fracture surgery and orienting an acetabular cup during total hip replacement surgery. The system also allows surgeons to view previously placed hardware without requiring new x-ray images and retain virtual features from one step of the procedure to another. The virtual features can include modeling of physical features that are not physically present on the instrument but can still provide additional information. The system uses a probe to non-invasively determine the location of landmarks on the pelvis and automatically registers the images. Overall, the system improves the accuracy and efficiency of surgical procedures and promotes a safer and less invasive surgical technique."

Problems solved by technology

Some surgeons prefer to use a drill guide with a single bore, but doing so may make it difficult to achieve the desired triangular spacing and optimum placement of the guide pins in the femoral neck.

Other surgeons prefer a drill guide with multiple bores that are fixed in the proper triangular spacing, but this requires a larger incision and doesn't permit the surgeon much flexibility to modify the preset pattern.

With either drill guide, it can be difficult to accurately predict the final guide pin placement.

Further, the surgery requires a significant number of fluoroscopic images and x-ray exposure for the surgeon, patient and operating room staff.

These systems, however, do not provide help in selecting paths that will lead to the desired triangular pattern with proper spacing between screws.

On the other hand, a tracked drill guide with multiple bores may be used, but this requires a large incision and does not leave the surgeon with flexibility in the spacing or orientation (e.g., parallel vs. diverging) of the screws.

Cups that are not properly oriented can lead to dislocation of the new hip and may require reoperation to reorient the cup.

However, it can be quite difficult to orient the acetabular cup correctly.

This problem is even worse with obese patients.

Further, the pelvis may be tilted relative to the operating table, making it difficult to use the table or any vertical or horizontal plane as a reliable reference.

While this system can improve the accuracy, and even the surgical outcome of the total hip procedure, it requires a CT scan which is not currently required, and a potentially time consuming intraoperative registration step.

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