Sunday, December 14, 2008

AAEP Convention Report: Digital Extension Device Details from Hans Castelijns

German veterinarian Eva Kr├╝dewagen learns to use the hoof lifter at a clinic in Germany. Dr. Hans Castelijns kneels at right. Photo by Loic Entwistle.

And now for something completely different: German farrier/veterinarian Hans Castelijns gave several lectures at the 2008 American Association of Equine Practitioners Convention in San Diego, California. In a special session on lameness in the foot in Monday, he presented a tool that has, as yet, not hit the radar of American-style lameness diagnosis.

Castelijns is a referral vet/farrier and runs a rehabilitation farm in the Tuscany region of Italy, when he's not harvesting his olive groves or traveling the world as a lecturer and thought-provocateur.

His tool is a multi-level aluminum-encased disk that the horse stands on; the top surface is covered with a non-slip pad. A long lever arm extends from the center of the disk. It cranks the disk up to displace medial or lateral, toe or heel, regions of the foot, to test for discomfort, or perhaps more precisely, to gauge the horse's range of comfort. The horse protests when too much torque is placed on the foot, indicating ligament pain or general intolerance to uneven weightbearing.

Closeup view of the digital extension device: the center plate swivels quite elegantly so the operator can move around the horse while the horse stands still and does not have to have its foot repeatedly placed on and off the device. The opposite leg is still held up by a helper. (Loic Entwistle image)

Swiss farrier Bernard Duvernay demonstrated the device at the wonderful Luwex HufSymposium in Germany in 2006.

The lever arm has an angle gauge and a level at the end, so the operator can say, "Before we trimmed him, he had a medial intolerance at x degrees. With this new trim, he showed no intolerance at all."

The tool is a massive sophistication of the basic lever test for navicular pain; veterinarians formerly stood horses on a board and lifted it, higher and higher to extend the coffin joint and stress the navicular zone, including the deep digital flextor tendon and the navicular ligaments, while an assistant lifted the opposite foot (see photo below). Horses with navicular pain shivered their upper leg muscles, jumped right off the board or buckled backward. The test was often dangerous for all involved; sometimes diagnostic tests would try to lift the foot from the side to elevate the lateral side of the foot, so that pain in the collateral ligaments might be identified.

French veterinarians with a customized board for navicular zone reaction testing; one end has been covered with a non-slip pad, while the operator end has a handle for pulling up. Notice that the board is long enough to keep the diasnostician somewhat clear of the horse in case it rears up or jumps off. (Photo courtesy of Tildren educational series in Hoofcare and Lameness Journal.)

While digital extension tests with a board may not be very accurate in pinpointing the source of pain, they can be helpful, particularly in the field, and they are useful for before and after illustrations of horses reactions pre- and post-shoeing or trimming or surgery. Castilijns has developed a protocol for the use of the more sophisticated tool and also has pinpointed areas that he feels are sensitive to specific elevations.

Castilijns's paper is published in the official Proceedings of the AAEP Convention. An older paper on the device is published in the English language section of his excellent web site. Click here to read the older paper.

The device is sold commercially in Europe.

© 2008 Fran Jurga and Hoofcare Publishing. No use without permission. You only need to ask.

Fran Jurga's Hoof Blog is a between-issues news service for subscribers to Hoofcare and Lameness Journal. This blog may be read online at the blog page, checked via RSS feed, or received via a digest-type email (requires signup in box at top right of blog page).

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