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Finite Element Analysis of Stress Distribution in Canine Lumbar Fractures with Different Pedicle Screw Insertion Angles
by
, and
Ziyao Zhou
1,†, 
Xiaogang Shi
2,†, 
Jiahui Peng
1,†,
Xiaoxiao Zhou
3,
Liuqing Yang
4,
Zhijun Zhong
1, 
Haifeng Liu
1,
Guangneng Peng
1,
Chengli Zheng
4,* and
Ming Zhang
5,* 1
Teaching Veterinary Hospital, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China
2
Sichuan Wolong National Natural Reserve Administration Bureau, Wenchuan 623006, China
3
Chengdu Center for Animal Disease Prevention and Control, Chengdu 610041, China
4
Sichuan Institute of Musk Deer Breeding, Sichuan Institute for Drug Control, Chengdu 611130, China
5
College of Animal Science, Sichuan Agricultural University, Chengdu 611130, China
*
Authors to whom correspondence should be addressed.
†
These authors contributed equally to this work.
Vet. Sci. 2025, 12(7), 682; https://doi.org/10.3390/vetsci12070682 (registering DOI)
Submission received: 3 June 2025
/
Revised: 13 July 2025
/
Accepted: 18 July 2025
/
Published: 19 July 2025
(This article belongs to the Special Issue Advanced Therapy in Companion Animals—2nd Edition)
Simple Summary
Back injuries, especially fractures in the lower spine, are common in dogs. Surgeons often use special screws to stabilize these fractures, but the best angle to place these screws is not well understood. In this study, we used computer simulations to test how different screw angles affect stress and movement in a dog’s spine. We created a 3D model of a beagle’s lower back from CT scans and tested screws inserted at angles between 45° and 65°. Our results showed that screws placed at 58° caused the least stress on the spine, while angles between 56° and 60° provided the most stable fixation. This information can help veterinarians perform safer and more effective surgeries for dogs with spinal fractures. Future research should test these findings in real surgeries and different dog breeds.
Abstract
Pedicle screw fixation is a critical technique for stabilizing lumbar fractures in canines, yet the biomechanical implications of insertion angles remain underexplored. This study aims to identify optimal screw trajectories by analyzing stress distribution and deformation patterns in beagle lumbar segments (L6-L7) using finite element analysis (FEA). A 3D finite element model was reconstructed from CT scans of a healthy beagle, incorporating cortical/cancellous bone, intervertebral disks, and cartilage. Pedicle screws (2.4 mm diameter, 22 mm length) were virtually implanted at angles ranging from 45° to 65°. A 10 N vertical load simulated standing conditions. Equivalent stress and total deformation were evaluated under static loading. The equivalent stress occurred at screw–rod junctions, with maxima at 50° (11.73 MPa) and minima at 58° (3.25 MPa). Total deformation ranged from 0.0033 to 0.0064 mm, with the highest at 55° and the lowest at 54°. The 58° insertion angle demonstrated optimal biomechanical stability with minimal stress concentration, with 56–60° as a biomechanically favorable range for pedicle screw fixation in canine lumbar fractures, balancing stress distribution and deformation control. Future studies should validate these findings in multi-level models and clinical settings.
