A comparison of the effects of local analgesic solution in the navicular bursa of horses with lameness caused by solar toe or solar heel pain.

The research investigates the impact of local analgesia in the navicular bursa on horses exhibiting lameness due to pain in different parts of their sole. In their study, the researchers discovered that administering local pain-relieving solution to the navicular bursa reduced lameness in horses with pain in the dorsal margin of the sole, but was less effective for those with pain in the heel area of the sole.

Research Methodology

• The research team conducted this examination to investigate an assumption regarding the specificity of analgesia of the navicular bursa.
• A hypothesis was formed that analgesia in the navicular bursa is not selective for the navicular apparatus, and that it could also be used to temporarily alleviate sole pain in horses.
• The team used the method of causing lameness in horses by inducing pain in the dorsal margin or the angles of the sole. This enabled them to assess the effectiveness of a locally administered analgesic solution into the navicular bursa in reducing lameness.
• The experiment was performed on 6 horses in which lameness was artificially induced by creating solar pain in the dorsal aspect of one forefoot and at a different time, the heel aspect of the foot.

Investigation and Findings

• The horses were monitored videographically during their trotting movement before and after application of set-screws (used to cause pain) and after administering the local analgesic solution into the navicular bursa.
• An analysis of the video-taped gaits was performed to assign lameness scores. A significant reduction in the scores was noted in instances where the set-screws were applied to the dorsal margin of the sole after the administration of the pain-relieving solution into the navicular bursa.
• The same level of effectiveness was however not observed when the pain was induced in the heel area. In these instances, the impact of the analgesic solution on reducing lameness signs was less pronounced.

Conclusion

• Based on the findings of their experimental study, the researchers concluded that the application of analgesia in the navicular bursa is less effective in numbing the angles of the sole compared to the dorsal margin.
• Despite the ability to reduce lameness signs through bursa analgesia, it is cautioned that sole pain should not be ruled out as a cause of lameness since the analgesic solution is not as effective at attenuating pain caused in the heel region of the sole.