The effect of unilateral resection of segments of both palmar digital arteries on the navicular bone in ponies: an experimental study.
Authors: Rijkenhuizen, Nèmeth, Dik, Goedegebuure, Van den Brom
Journal: Equine veterinary journal
Summary
# Editorial Summary This experimental study investigated how disrupting the primary arterial blood supply to the distal limb affects the navicular bone and clinical function. Researchers surgically resected segments of both the medial and lateral palmar digital arteries in one forelimb of ponies, then monitored clinical signs, radiographic changes, scintigraphic (nuclear) imaging, and histological bone samples over the recovery period. Acute lameness occurred immediately following arterial resection due to the sudden ischaemic insult before collateral circulation could compensate; however, compensatory vascular pathways developed sufficiently that permanent ischaemic symptoms did not persist, and radiographic abnormalities did not become apparent. Histologically, the operated limbs showed significantly elevated relative osteoid volume compared to control limbs, indicating altered bone remodelling and increased unmineralised bone matrix—a finding suggestive of compromised bone quality despite functional recovery. These findings have practical relevance for understanding navicular disease pathogenesis, particularly in cases where vascular compromise may contribute to bone degradation, and suggest that acute arterial insufficiency triggers observable changes in bone metabolism even when clinical compensation occurs.
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Practical Takeaways
- •Acute disruption of palmar digital arterial supply causes temporary lameness, but the horse's ability to develop collateral circulation prevents permanent ischaemic damage in this experimental model
- •Histological changes (increased osteoid) occur even when clinical signs resolve, suggesting tissue-level effects persist despite functional recovery
- •Understanding navicular bone blood supply and compensatory mechanisms may inform treatment approaches for navicular syndrome and chronic foot pain in ponies and horses
Key Findings
- •Acute resection of medial and lateral palmar digital arteries caused immediate lameness due to insufficient collateral circulation development
- •Despite partial resection of both palmar digital arteries, no permanent ischaemic symptoms occurred due to compensatory collateral circulation
- •Histologically, the operated limb showed significantly higher relative osteoid volume compared to the control limb