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Computer Assisted Surgery

Computer assisted surgery for orthopaedic procedures

Computer Assisted Surgery (CAS) technology allows the surgeon to simultaneously visualize two- or three-dimensional views of the patient's anatomy on a monitor, and provides real-time, intra-operative views of surgical instruments and the relative digital positioning of implantable devices.

Most CAS systems obtain images prior to or during surgery using a variety of diagnostic imaging modalities including CT, MR and fluoroscopy. These images are often further processed to provide the surgeon with three-dimensional intra-operative images of the patient's anatomy. Alternatively, in "imageless" CAS systems, data points are harvested from the anatomy to create a 3-D bone model. During the surgical procedure, fixed sensors are applied to the patient and additional sensors are incorporated into the surgical instruments or implants. These surgical navigation data points allow the surgeon to view the precise angles and optimal positioning of the orthopaedic implant or the relative trajectory of the medical device or tool, such as a drill. Via this feedback, the surgeon is assisted in placing implants accurately and consistently - important determinants of the long-term success of orthopaedic procedures.

Overview & Clinical Summary

The use of CAS in orthopaedic surgery can provide the surgeon with increased anatomical measurement and better placement of orthopaedic implants, thereby improving the accuracy and potentially reducing the invasiveness of these procedures.

This overview discusses the various CAS systems and techniques, as well as the application of navigation in selected orthopaedic procedures. It also provides a brief summary of selected peer-reviewed published studies supporting the effectiveness of Computer Assisted Surgery for orthopaedic procedures.

Knee Arthroplasty

The accurate alignment of knee implants is a critical factor in success of total knee replacement. Although this procedure is generally successful in relieving pain and improving patient functioning, complications including implant loosening, instability, dislocation, or fracture occur in 5-8% of cases. Other less serious complications, such as pain and limited flexibility, occur in 20-40% of cases. Use of CAS may increase the accuracy and consistency of knee implant procedures, thereby reducing such complications and improving surgical outcomes. Absent the use of Computer Assisted Surgery during the surgical procedure, surgeons often use mechanical implant guides to improve the precision of knee implants, although errors in alignment still occur with these devices.

Published studies document the benefits of CAS in knee implant placement. For example, a case-control study compared postoperative implantation quality, as measured by pre-determined criteria, for 30 knee implant cases using Computer Assisted Surgery (the study group), and 30 cases using a surgeon-controlled technique (the control group). The authors found that 23 cases in the study group were implanted in an optimal manner, compared with only 8 cases in the control group. Based on these findings, the authors concluded that use of Computer Assisted Surgery in total knee replacement significantly improves the quality of implantation and could lead to improved long-term outcomes for these patients.

Click here to find out more about Computer assisted Knee replacement.

Coming soon is an interactive presentation on Computer assisted knee surgery.


The Vector Vision System is a "global positioning system for the body"
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