A nonterminal equine mandibular model of bone healing.
Authors: Sarrafian Tiffany L, Garcia Tanya C, Dienes Erin E, Murphy Brian, Stover Susan M, Galuppo Larry D
Journal: Veterinary surgery : VS
Summary
# Editorial Summary: A Nonterminal Equine Mandibular Model of Bone Healing Sarrafian et al. (2015) established a repeatable surgical model in six adult geldings to evaluate bone healing in standardised mandibular defects, addressing the need for robust preclinical testing platforms for regenerative and pharmacological interventions. The researchers created bilateral 13.5 mm full-thickness cortical defects in the lower jaw using a custom surgical jig, then harvested 23 mm cores encompassing the original defect sites after 16 weeks for detailed histological and radiographic analysis, with oxytetracycline administered pre-harvest to identify active bone formation. Defects healed centripetally from the margins, achieving approximately 67% (±16%) volumetric fill by week 16, with no significant difference in bone volume fraction between left and right sides, indicating reproducibility and symmetric healing patterns. The model's bilateral design and quantifiable healing metrics—including trabecular-to-cortical ratios, bone mineral density measures, and fluorescent bone labelling—provide a methodologically sound platform for comparing the efficacy of therapeutic agents intended to accelerate or improve mandibular bone healing. For practitioners and researchers developing new treatments, this model offers a validated alternative to terminal studies, permitting longitudinal assessment within a living subject whilst generating data sufficiently sensitive to detect treatment-related differences in bone regeneration.
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Practical Takeaways
- •This nonterminal mandibular model provides a validated method for testing new bone regeneration therapies in horses without euthanasia
- •Expect approximately two-thirds fill of similar-sized mandibular defects over 16 weeks under normal healing conditions—use as baseline for comparing regenerative treatments
- •The model's reproducibility and bilateral design make it suitable for pharmaceutical and regenerative product development in equine practice
Key Findings
- •Bilateral 13.5 mm mandibular defects in horses healed to approximately 67% ± 16% fill by 16 weeks post-surgery
- •Bone deposition occurred centripetally from the defect border with no significant difference in bone volume fraction between sides
- •The model successfully demonstrated trabecular and cortical bone formation assessed via microCT, histology, and fluorescent labeling