34th Annual Scientific Meeting proceedings

Computer-assisted surgery has become an integral part of many specialty fields in human medicine. However, its introduction was characterized by numerous “growing pains” and struggled for a long time to find widespread acceptance.¹ Similarly, we encounter challenges and pitfalls with introducing and applying this technology in equine surgery. With the acquisition of an advanced navigation system more than 15 years ago, we started out using the technology for a small number of selected cases at the Equine Clinic of the Vetsuisse Faculty Bern. Admittedly, this was done with minimal preparation and no pre-existing personal experience in navigated surgery. Thus, we initially depended heavily on the manufacturer's on-site technical support to avoid technical glitches and work as efficiently as possible. Nonetheless, these hands-on experiences soon convinced us of the great potential of this technology.

Based on earlier publications, we anticipated the main benefit of CAS to be in orthopaedic surgery, i.e. computer-assisted orthopaedic surgery (CAOS).^2-4 Whereas highly specialized equipment is available for CAOS in humans, we normally work with regular surgical instrumentation that is equipped with exchangeable trackers for optical tracking systems. We realized, however, that we needed to adapt and complement the existing equipment to make the best use of this technology in large animal surgery. This triggered several cadaveric studies including a project to develop a purpose-built frame (PBF) to facilitate CAOS procedures performed on the equine digit and metacarpal/metatarsal region.⁵ The specialized equipment developed and the experiences gained in these projects paved the way for integrating this technology into our clinical routine.⁶ Because surgeons and support staff are well-familiarized with the technology, because occupation-related radiation through intra-operative imaging is effectively avoided, but more importantly because we as surgeons clearly benefit from the intraoperative orientation and real-time guidance, it has become the go-to modality for all orthopaedic interventions that rely on intraoperative image guidance.

Here, we will share our experiences with CAOS. Based on a selection of particularly challenging clinical cases, consisting of previously published^6-10 and unpublished material, we will present the versatility and practicality of this technology. At the same time, we will point out common pitfalls, like line-of-sight issues, problems with instrument calibration, and potential sources contributing to prolonged anaesthesia duration and the loss of surgical accuracy. Finally, we will provide practical advice on how to effectively avoid these pitfalls and issues in a clinical setting (Table 1).

Table 1: Practical pointers to optimize workflow and minimize technical glitches in computer-assisted orthopaedic surgery.

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.
7. Claeys I, Van der Vekens E, Kummerle J, et al. Computer-assisted surgery for placing toggle constructs across the coxofemoral joints of small equids using a minimally invasive approach-A proof-of-concept cadaveric study. Vet Surg. 2023;52:994-1008.
8. de Preux M, van der Vekens E, Racine J, et al. Accessory carpal bone fracture repair by means of computer-assisted orthopaedic surgery in a Warmblood stallion. Equine Vet Educ. 2022;34(11):e478-e484.
9. Greim E, de Preux M, Koch C, et al. Computer-assisted removal of an ectopic tooth from the mandibular fossa through a mandibular condylectomy approach in a Comtois gelding. Equine Vet Educ.  2023;35(5):e364-e371.
10. de Preux M, Precht C, Guevar J, et al. A transmandibular lateral transsphenoidal navigated surgical approach to access a pituitary macroadenoma in a warmblood mare. Vet Q. 2024;44:1-10.