Effect of anaesthesia of the palmar digital nerves on proximal interphalangeal joint pain in the horse.

This research studies the effect of anesthesia on the palmar digital nerves to decrease lameness in horses suffering from pain in the proximal interphalangeal (PIP) joint. Results indicate that administering anesthesia can significantly improve the condition, but not when applied too close to the foot cartilages.

Objective and Methods

• The researchers aimed to determine how effectively the pain was reduced in horses when they were administered anesthesia on their palmar digital nerves.
• The horses’ movements were video recorded before and after the pain induction in the PIP joint (located in the foot) and ten minutes after administering anesthesia.
• Anesthesia was performed three times at different places on the palmar digital nerves and the effect was then measured based on changes observed in the video recordings of horses’ movements (gaits).

Results

• The pain administration was conducted by injecting 2% mepivacaine 1 cm above the foot cartilages. The results showed no significant difference in the lameness levels pre-and post-anesthesia.
• In one out of six horses, a notable improvement was observed.
• An effective decrease in lameness was noticed when mepivacaine was injected 2 cm and 3 cm above the foot cartilages, indicating the injection’s location had an effect.

Conclusions

• An implication from the study is that PIP joint is likely not anesthetized if the anesthesia is carried out on the palmar digital nerves too close to the foot cartilages.
• The study concludes that if there is an improvement in lameness after anesthesia, it does not necessarily mean that the source of lameness – PIP joint pain – is resolved. It could be that lameness was reduced due to the impact of anesthesia on areas other than the PIP joint.