34th Annual Scientific Meeting proceedings

Computer-assisted orthopedic surgery (sometimes abbreviated as CAOS) is a discipline where computer technology is applied pre-, intra- and/or post-operatively to improve the outcome of orthopedic surgical procedures. The use of CAOS allows a more precise surgical navigation than the one provided by the surgeon using minimally invasive surgery for adequate fracture repair without the need to incur into tissue invasion destroying incipient vascular supply mechanisms to the fracture plane and increasing the risk of bacterial colonization with an associated infection. Since the necessary condition is to create a rigid enviroment between the fracture, the patient and the computer, where all elements are fixed in place, it is not applicable in those situations where open reduction is needed. CAOS is still an active research discipline which brings together orthopedic practitioners with traditionally technical disciplines like engineers. Its application requires much practice and surgical team organization in order to not bypass any necessary steps within the different stages which include, pre-operative planning, patient preparation, positioning, and acquisition or registration of all components  of the CAOS system, execution of the plan and validation.

Although CAOS has advantages in both the accuracy and precision of the procedure at hand, it is still not widely accepted within the human orthopedic or veterinary communities due to cost and the “lack of trust” in an imageless navigation system which relies heavily upon the skill of the surgeon to input accurate values and to control the required rigid environment. In the distal extremity, CAOS is extremely valuable due to the advantages of performing minimally invasive procedures. In the distal extremity there is not much soft tissue coverage and preserving the natural biological fracture enviroment is an advantage. In oder situations, like in the navicular region, the hidden nature of the bone and its irregular and curvilinear shape makes it a perfect candidate for this type of procedure. While fracture repair in cases of phalangeal fractures can be accomplished successfully with more traditional approaches, we take advantage of using CAOS in order to continue becoming adept at using the technology in preparation for more challening cases. Practice with simple cases is paramount to train surgeon’s abilities and gain confidence. We will show some cases repaired with the aid of CAOS technology and the system used as well as potential sources of errors. Although CAOS is still not widely accepted by many orthopedic surgeons, it is shown to be an incredibly useful tool in improving implant placement accuracy and also training of new surgeons due to the creation of images that help visualizing anatomical landmarks for procedures.

References

1. Zheng G, Nolte LP. Computer-Assisted Orthopedic Surgery: Current State and Future Perspective. Front Surg. 2015;2:66.
2. Andritzky J, Rossol M, Lischer C, et al. Comparison of computer-assisted surgery with conventional technique for the treatment of axial distal phalanx fractures in horses: an in vitro study. Vet Surg. 2005;34:120-127.
3. Gygax D, Lischer C, Auer JA. Computer-assisted surgery for screw insertion into the distal sesamoid bone in horses: an in vitro study. Vet Surg. 2006;35:626-633.
4. Rossol M, Gygax D, Andritzky-Waas J, et al. Comparison of computer assisted surgery with conventional technique for treatment of abaxial distal phalanx fractures in horses: an in vitro study. Vet Surg. 2008;37:32-42.
5. de Preux M, Vidondo B, Koch C. Influence of a purpose-built frame on the accuracy of computer-assisted orthopedic surgery of equine extremities. Vet Surg. 2020;49:1367-1377.
6. de Preux M, Klopfenstein Bregger MD, Brunisholz HP, et al. Clinical use of computer-assisted orthopedic surgery in horses. Vet Surg. 2020;49:1075-1087.