Lameness of horses is effectively ameliorated with a low volume of mepivacaine administered as a palmar digital nerve block.

The research investigates the effectiveness of low volumes of mepivacaine, a local anesthetic, in treating lameness in horses caused by digital pain. The research states that administering a smaller than traditionally recommended volume provides an equally effective treatment and may help isolate the source of pain more accurately.

Study Design

• The study was designed as a cross-over trial involving six horses experiencing lameness due to forefoot-related pain. The horses were randomly divided into three groups.
• Each group was given different treatments on separate study days – 1.5 mL of 2% mepivacaine, 0.75 mL 2% mepivacaine, or 0.75 mL of a combination of 2% mepivacaine and epinephrine.
• The mepivacaine or its combination was administered over each palmar digital nerve (PDN), the nerves located in the foot of the horse.
• Each horse’s gait was analyzed before treatment and reevaluated at 5-minute intervals for a period of 15 minutes post-treatment.

Study Results

• All three treatments – 1.5mL and 0.75 mL mepivacaine alone and in combination with epinephrine – significantly reduced lameness scores in the horses at all gait evaluations.
• There was no notable difference found in the level of effectiveness between the three different treatments – suggesting that 0.75 ml of mepivacaine is as efficient as 1.5ml.
• The addition of epinephrine to the mepivacaine solution did not necessarily enhance the anesthetic effect.

Conclusions

• Lower than commonly recommended volumes of 2% mepivacaine were found to ameliorate digital pain as effectively as higher volumes.
• The study suggests that using a smaller amount of anesthetic might allow for more precise localization of pain, a prospect that could guide further research.