Development and Finite Element Analysis of a Patient-Specific Implant for Atlantoaxial Joint Stabilization via Dorsal Approach in Dogs

Abstract

Objective To develop a patient-specific implant designed for dorsal access instrumentation, which also serves as a guide for screw insertion, for use in dogs with atlantoaxial instability. The implant must demonstrate no failure in finite element analysis.

Study Design The development of an implant utilizing computational resources based on a computed tomography scan of a patient with atlantoaxial instability. The final implant model was analysed using finite element methods in flexion, extension, lateral flexion, and torsion to evaluate stress distribution and displacement.

Results A patient-specific implant for dorsal instrumentation was developed, featuring six holes for the insertion of 1.7-mm bicortical locking screws, including two transarticular screws and two additional screws per vertebra. The implant demonstrated a maximum stress point of 425 MPa, well below the material yield strength of 880 MPa, with a maximum displacement of only 0.13 mm.

Conclusion The proposed implant shows promise as it can function as a drilling guide, potentially enhancing safety during instrumentation. Using safe corridors may improve the rigidity of the construct. The implant model did not exhibit any failure when subjected to finite element analysis according to the established criteria.

Keywords

3D modelling - implant design - atlantoaxial instability - neurosurgery - atlantoaxial subluxation

Publication History

Received: 19 October 2024

Accepted: 04 March 2025

Article published online:
02 April 2025

• References

• 1 Geary JC, Oliver JE, Hoerlein BF. Atlanto axial subluxation in the canine. J Small Anim Pract 1967; 8 (10) 577-582
• 2 Stalin C, Gutierrez-Quintana R, Faller K, Guevar J, Yeamans C, Penderis J. A review of canine atlantoaxial joint subluxation. Vet Comp Orthop Traumatol 2015; 28 (01) 1-8
• 3 Beaver DP, Ellison GW, Lewis DD, Goring RL, Kubilis PS, Barchard C. Risk factors affecting the outcome of surgery for atlantoaxial subluxation in dogs: 46 cases (1978-1998). J Am Vet Med Assoc 2000; 216 (07) 1104-1109
• 4 Shores A, Tepper LC. A modified ventral approach to the atlantoaxial junction in the dog. Vet Surg 2007; 36 (08) 765-770
• 5 Dickomeit M, Alves L, Pekarkova M, Gorgas D, Forterre F. Use of a 1.5 mm butterfly locking plate for stabilization of atlantoaxial pathology in three toy breed dogs. Vet Comp Orthop Traumatol 2011; 24 (03) 246-251
• 6 Cummings KR, Vilaplana Grosso F, Moore GE, Rochat M, Thomovsky SA, Bentley RT. Radiographic indices for the diagnosis of atlantoaxial instability in toy breed dogs [corrected]. Vet Radiol Ultrasound 2018; 59 (06) 667-676
• 7 Havig ME, Cornell KK, Hawthorne JC, McDonnell JJ, Selcer BA. Evaluation of nonsurgical treatment of atlantoaxial subluxation in dogs: 19 cases (1992-2001). J Am Vet Med Assoc 2005; 227 (02) 257-262
• 8 Tabanez J, Gutierrez-Quintana R, Kaczmarska A. et al. Evaluation of a novel dorsal-cemented technique for atlantoaxial stabilisation in 12 dogs. Life (Basel) 2021; 11 (10) 1039
• 9 Slanina MC. Atlantoaxial instability. Vet Clin North Am Small Anim Pract 2016; 46 (02) 265-275
• 10 Lu Y, Yang Z, Wang Y. Proc Inst Mech Eng. A critical review on the three-dimensional finite element modelling of the compression therapy for chronic venous insufficiency. Proc Inst Mech Eng H 2019; 233 (11) 1089-1099
• 11 Welch-Phillips A, Gibbons D, Ahern DP, Butler JS. What is finite element analysis?. Clin Spine Surg 2020; 33 (08) 323-324
• 12 Reber K, Bürki A, Vizcaino Reves N. et al. Biomechanical evaluation of the stabilizing function of the atlantoaxial ligaments under shear loading: a canine cadaveric study. Vet Surg 2013; 42 (08) 918-923
• 13 ASTM International. ASTM F136–13(2021) e1 - Standard Specification for Wrought Titanium-6Aluminum-4Vanadium ELI (Extra Low Interstitial) Alloy for Surgical Implant Applications (UNS R56401). Washington, DC: ASTM International; 2021
• 14 Leblond G, Gaitero L, Moens NMM. et al. Computed tomographic analysis of ventral atlantoaxial optimal safe implantation corridors in 27 dogs. Vet Comp Orthop Traumatol 2017; 30 (06) 413-423
• 15 Toni C, Oxley B, Behr S. Atlanto-axial ventral stabilisation using 3D-printed patient-specific drill guides for placement of bicortical screws in dogs. J Small Anim Pract 2020; 61 (10) 609-616
• 16 Leblond G, Gaitero L, Moens NM. et al. Canine atlantoaxial optimal safe implantation corridors—description and validation of a novel 3D presurgical planning method using OsiriX™. BMC Vet Res 2016; 12 (01) 188
• 17 MacLeod AR, Pankaj P. Pre-operative planning for fracture fixation using locking plates: device configuration and other considerations. Injury 2018; 49 (Suppl. 01) S12-S18
• 18 Goel A, Desai KI, Muzumdar DP. Atlantoaxial fixation using plate and screw method: a report of 160 treated patients. Neurosurgery 2002; 51 (06) 1351-1356 , discussion 1356–1357
• 19 Niu HG, Zhang JJ, Yan YZ, Zhao CK, Yang K, Zhang YS. Design of a novel lateral mass screw-plate system for the treatment of unstable atlas fractures: a finite element analysis. J Orthop Surg Res 2024; 19 (01) 120
• 20 Beer FP, Johnston ER, Dewolf JT, Mazurak DF. Mechanics of Materials. 7th ed.. New York: McGraw Hill; 2014