34th Annual Scientific Meeting proceedings

Use of 3D printing as a surgical aid has gained popularity in both human and veterinary surgery. Proposed benefits of 3D printing include development of patient specific implants, surgical rehearsal prior to entering the OR, the ability to pre-contour implants, and reduction of surgical and/or anesthesia time.^1,2 Despite the gain in popularity, there are still some barriers to widespread use of 3D printing including the cost, turnaround time, and training required to print models in-house.¹

Use of 3D printing in veterinary surgery is most often described during the treatment of angular limb deformities (ALDs). Many complex ALDs are difficult to assess in two dimensions so 3D imaging and printing allow for more thorough evaluation of the deformity in all planes. Additionally, 3D printing can be used to create surgical guides using the patient’s unique anatomy helping to increase accuracy of the surgery. Previous studies have compared the planned ALD correction (using 3D printing) and the actual post surgical correction and noted joint angles to be within 3.5-7.5 degrees of each other in one study³ and within 5mm of acceptable values for 90% of frontal, sagittal, axial, and translational alignment values in another.⁴

Three-dimensional printing has also been used to improve accuracy of implants placed where visualization is limited. One area where this has been investigated is neurologic surgery where implants must be placed within narrow corridors around delicate structures. A 2020 study comparing placement of screws in LS vertebrae showed that 42.6% of screws placed “free hand” penetrated the vertebral canal whereas only 14% placed using 3D guides penetrated the canal.⁵ A later study showed only ~6% of screws placed in the L7 pedicle using a 3D printed guide penetrated the canal (and all penetrated less than 1/3 of the screw diameter).⁶ Use of 3D printed guides may therefore facilitate proper implant placement and lead to a decrease in complications due to malposition of implants.

As 3D printing is further implemented into surgical protocols, there are potential complications/issues to consider including the additional cost to owners, the time to process and create models, lack of standardized methods for joint/ALD measurement on 3D images, and soft tissues that may interfere with guide placement. For in house printing, additional factors to consider include the need for software training, learning curve for guide development, and start-up and maintenance costs (such as for software, printers, and resin).¹ In order to increase the likelihood of success while working with 3D printing, development of quality control protocols for all steps (from the CT scan to the surgical procedure) is essential.⁷ Additionally, one should always remember that 3D models and guides are an aid for surgery not a replacement for critical thinking.

References

1. Altwal J, Wilson CH, Griffon DJ. Applications of 3-dimensional printing in small-animal surgery: A review of current practices. Vet Surg. 2022;51(1):34-51. doi:10.1111/vsu.13739
2. Winer JN, Verstraete FJM, Cissell DD, Lucero S, Athanasiou KA, Arzi B. The application of 3-dimensional printing for preoperative planning in oral and maxillofacial surgery in dogs and cats. Vet Surg. 2017;46(7):942-951. doi:10.1111/vsu.12683
3. Carwardine DR, Gosling MJ, Burton NJ, O’Malley FL, Parsons KJ. Three-Dimensional-Printed Patient-Specific Osteotomy Guides, Repositioning Guides and Titanium Plates for Acute Correction of Antebrachial Limb Deformities in Dogs. Vet Comp Orthop Traumatol. 2021;34(1):43-52. doi:10.1055/s-0040-1709702
4. De Armond CC, Lewis DD, Kim SE, Biedrzycki AH. Accuracy of virtual surgical planning and custom three-dimensionally printed osteotomy and reduction guides for acute uni- and biapical correction of antebrachial deformities in dogs. J Am Vet Med Assoc. 2022;260(13):1-9. doi:10.2460/javma.21.09.0419
5. Beer P, Park BH, Steffen F, Smolders DLA, Pozzi A, Knell SC. Influence of a customized three-dimensionally printed drill guide on the accuracy of pedicle screw placement in lumbosacral vertebrae: An ex vivo study. Vet Surg. 2020;49(5):977-988. doi:10.1111/vsu.13417
6. Mariani CL, Zlotnick JA, Harrysson O, et al. Accuracy of three-dimensionally printed animal-specific drill guides for implant placement in canine thoracic vertebrae: A cadaveric study. Vet Surg. 2021;50(2):294-302. doi:10.1111/vsu.13557
7. Fitzwater KL, Marcellin-Little DJ, Harrysson OLA, Osborne JA, Poindexter EC. Evaluation of the effect of computed tomography scan protocols and freeform fabrication methods on bone biomodel accuracy. Am J Vet Res. 2011;72(9):1178-1185. doi:10.2460/ajvr.72.9.1178