Efficacy of ketamine hydrochloride administered as a basilar sesamoid nerve block in alleviating foot pain in horses caused by natural disease.
Authors: Schumacher J, DeGraves F, Cesar F, Duran S
Journal: Equine veterinary journal
Summary
# Editorial Summary: Ketamine for Basilar Sesamoid Nerve Blocks in Horses Diagnostic nerve blocks using local anaesthetics are essential tools for localising sources of foot pain in lame horses, yet the duration of action can be limiting when performing sequential blocks. Schumacher and colleagues investigated whether ketamine hydrochloride might offer advantages over lidocaine when administered as a basilar sesamoid nerve block, using wireless inertial motion analysis to objectively measure lameness in seven chronically lame horses before and after drug administration at five-minute intervals over 30 minutes. Whilst lidocaine (2%) produced statistically significant improvement in gait, ketamine (3%) failed to achieve comparable desensitisation of the digit, demonstrating no meaningful effect on lameness scores. The authors conclude that ketamine lacks sufficient local anaesthetic potency when delivered perineurally for diagnostic purposes in equine practice, making it unsuitable as a replacement for lidocaine despite its theoretical advantage of rapid offset. For practitioners relying on sequential diagnostic blocks to pinpoint foot pain, lidocaine remains the standard of choice for basilar sesamoid nerve blocks, and alternative approaches—rather than alternative agents—should be considered when timing constraints are problematic.
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Practical Takeaways
- •Lidocaine remains the standard local anaesthetic for basilar sesamoid nerve blocks in diagnosing foot pain; ketamine is not an effective alternative
- •Do not use 3% ketamine for regional anaesthesia of the equine digit as it will not adequately desensitise the area or improve lameness diagnostically
- •For horses with chronic foot lameness, rely on lidocaine-based basilar sesamoid nerve blocks to confirm pain origin and guide further treatment planning
Key Findings
- •Gait significantly improved after basilar sesamoid nerve blocks using 2% lidocaine in all 7 lame horses
- •Gait did not significantly improve after the same nerve block procedure using 3% ketamine HCl
- •Ketamine (3%) administered perineurally does not desensitise the digit to the same extent as lidocaine
- •3% ketamine has no value as a local anaesthetic agent for diagnostic regional anaesthesia of the equine digit