Equine Lameness

Nerve block challenge answers

  1. What sort of anesthetic agent would you use to perform a lameness examination and why?

(We typically use lidocaine, mepivicaine, or bupivicaine as local anesthetics but in different situations. )

We typically use mepivicaine (Carbocaine) as it provides a moderate duration of activity (about 2 hours), has a relatively rapid onset of action (10 min), and is relatively nonirritating. Lidocaine is used when you want a fast response (3 min) and want it to wear off quickly (or don’t care if it does). However, it can be more irritating and the duration depends upon the animal. Bupivicaine is used for long lasting blocks (eg the treatment of laminitis or pain control).

  1. How would you block out the entire foot?

Basal sesamoid (abaxial) nerve block

check for sensation at the dorsal coronet to make sure the entire foot is blocked

  1. How would you block out the fetlock? Give 2 options.

Low volar (4 point) nerve block or fetlock joint block. Volar = palmar or plantar

  1. How would you block the suspensory ligament?

Regional infiltration, high volar (4 point) or modified high volar (2 point) nerve block

  1. How would you evaluate a horse for bone spavin?

Inject the tarsometatarsal +/- the distal intertarsal joints

  1. How could you block the tibiotarsal joint? Give 2 options.

Intraarticular injection or tibial and peroneal nerve blocks

  1. There are 3 joint pouches in the stifle. Do you need to block all three separately?

What about the 3 joints of the carpus? The hock?

Stifle : usually the medial femorotibial and femoropatellar joints communicate but only one in four lateral femorotibial joints communicate with the femoropatellar joint.

       Carpus : the intercarpal and carpometacarpal joints communicate

Hock : sometimes the tarsometatarsal and distal intertarsal joints communicate; the proximal intertarsal and tibiotarsal joints usually communicate

  1. Are there any complications related to local anesthetic procedures?

Local irritation and swelling is possible with larger volumes (eg volar blocks)

Risk of creating a septic joint is always a possibility with intraarticular injections but is low with proper preparation of the joint

  1. How long will the anesthetic last (eg if you want to do a different block, how long will you have to wait)?

It depends on if you want it to or not. With mepivicaine, count on at least 2 hours, but it may take up to 4; with lidocaine, it should be gone in 1-2 hours

License

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Large Animal Surgery - Supplemental Notes by Erin Malone, DVM, PhD; Elaine Norton, DVM PhD; Erica Dobbs, DVM; and Ashley Ezzo, DVM is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, except where otherwise noted.