Lameness Examination Diagnostics
Nerve or Joint Block Procedure
A dynamic motion and static physical examination lay the foundation that help determine which diagnostic processes will be of value.
Particularly in cases of limb lameness, nerve or joint "blocks" are used to further localize and rule out a myriad of other possibilities.
Blocking can be a vital part of the diagnostic process. You should expect to have this procedure included in your lameness evaluation.
After a sterile preparation of the skin called "scrubbing", a small amount of anesthetic, similar to Novocaine that is used by human dentists, is injected under the skin near the nerve or nerve bundles or directly into the joint. The horse is then evaluated in motion to determine if there is improvement due to "blocking" of the pain signal. The amount of time we wait between administration and evaluation depends on which block we are using. We may evaluate the horse right away or we may wait 15 minutes. If there has been no improvement in lameness, we go onto the next level of blocks. The first block will always be the lowest on the limb and we work our way up the limb as needed. Most nerve blocks and some joint blocks do not require bandaging but there are some joint blocks that are protected by a bandage.
How much time does it take?
Blocking can take a half hour or 3 hours, it just depends on how far up the limb we have to go. Occasionally, it is necessary to block again on another day to prove the location of pain has been adequately identified. If multiple blocks have been done, most horses will get intravenous phenylbutasone "IV bute" to minimize tissue inflammation from needle insertion.