Thoracolumbar Spinal Stabilization with Three Dimensional-Printed Drill Guides and Pre-Contoured Polyaxial Bone Plates

Oliver Gilman, Leticia Escauriaza, Dan Ogden, Helene Vandenberghe, Darren Roper, Bill Oxley, Nicolas Granger
Vet Comp Orthop Traumatol. 2022 Nov 22. doi: 10.1055/s-0042-1756514.

Objective: The aim of this study was to report new preoperative and intraoperative techniques performed for canine thoracic or lumbar spine kyphosis stabilization using three-dimensional-printed patient-specific drill guides, polyaxial titanium bone plates and drill stops, and to determine the accuracy of screw placement using these techniques.

Study design: Retrospective study, five client-owned dogs.

Results: Three-dimensional-printed patient-specific drill guides and drill stops allowed safe drilling and screw placement in all of the cases, with (i) 84% of the screws graded as I (ideal placement) and 16% as IIa, IIIa or IIIb according to the modified Zdichavsky classification (partial penetration of medial pedicle wall, partial penetration of lateral pedicle wall and full penetration of lateral pedicle wall respectively), (ii) mean mediolateral deviation of ± 4.06 degrees (standard deviation: 8.21 degrees) compared to planned trajectories and (iii) variation in screw depth of ± 2.29mm (standard deviation: 3.07mm) compared to planned depth.

Conclusion: We believe that the techniques presented here for thoracic spinal stabilization in dogs show promise; they allowed safe placement of screws along planned trajectories and depth; they also removed the need to use polymethylmethacrylate, while the use of titanium offers the possibility to repeat magnetic resonance imaging in these cases with chronic spinal conditions.