Vet Comp Orthop Traumatol 2022; 35(06): 381-389
DOI: 10.1055/s-0042-1750433
Original Research

Accuracy of Lumbosacral Pedicle Screw Placement in Dogs: A Novel 3D Printed Patient-Specific Drill Guide versus Freehand Technique in Novice and Expert Surgeons

1   School of Veterinary Medicine, University of Glasgow, Glasgow, United Kingdom
Nathan Wilkinson
2   Axia 3D Design (currently Nexus Engineering & Design Ltd), Napier, New Zealand
Manabu Kurihara
3   Cummings School of Veterinary Medicine at Tufts University, Crafton, United States
Janis P. Bridges
4   Massey University School of Veterinary Science, Palmerston North, New Zealand
Wendy Baltzer
5   University of Sydney, School of Veterinary Science, Sydney, New South Wales, Australia
4   Massey University School of Veterinary Science, Palmerston North, New Zealand
› Author Affiliations
Funding Funding for this project was provided by the Massey University Working Dog Centre, Palmerston North, New Zealand.


Objective The aim of this study was to compare the accuracy of pedicle screw placement at the canine lumbosacral junction using a novel unilateral three-dimensional printed patient-specific guide (3D-PSG) versus a freehand drilling technique. Additionally, accuracy of screw placement between a novice and an experienced surgeon was determined.

Study Design Preoperative computed tomography images from 20 lumbosacral cadaveric specimens were used to design a novel unilateral 3D-PSG for the L7 and sacral vertebrae which was printed in acryl-nitrile butadiene styrene plastic. A novice and an expert surgeon each placed 3.5mm cortical screws in 10 cadavers; on the left using the unilateral 3D-PSG and by the freehand (anatomic landmark) technique on the right.

Results Sixty screws were placed using the unilateral 3D-PSG and 60 using the freehand technique. There was no statistical difference in accuracy for the comparison between methods performed by the expert (p = 0.679) and novice (p = 0.761) surgeon, nor between an expert and novice surgeon overall (p = 0.923). Unexpectedly, the use of a unilateral 3D-PSG increased variability for the expert surgeon in our study (p = 0.0314).

Conclusion Using a novel unilateral 3D-PSG did not improve the accuracy of screw placement for lumbosacral stabilization by a novice surgeon compared with an expert surgeon in lumbar spine surgery. This may reflect a suboptimal PSG design.

Publication History

Received: 25 January 2021

Accepted: 04 May 2022

Article published online:
10 July 2022

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