Head Position Can Impact 'Tie-Forward' Assessment

How the horse's head is positioned for radiographs (X rays) evaluating the efficacy of a tie-forward surgery can have a dramatic impact on the results, researchers from the United Kingdom report.

The laryngeal tie-forward surgical technique might be indicated in horses diagnosed with dorsal displacement of the soft palate (DDSP), the abnormal movement of the soft palate in a dorsal (upwards) position during strenuous exercise so that it lies on top of the epiglottis rather than underneath it. DDSP can result in poor performance in athletic horses.

"Once the tie-forward has been performed in horses with DDSP, a radiograph is taken to assess if the larynx--the voice box--has truly been fixed in a more rostral (forward) position," explained study co-author Laura McCluskie, BVSc, from the department of clinical veterinary science at the University of Bristol.

Since changes in head position can alter the position of the larynx in humans, McCluskie and colleagues hypothesized that a similar phenomenon occurs in horses and sought to determine the most appropriate head position for assessing X rays after a tie-forward had been performed in nine Thoroughbred horses to treat DDSP.

"Our results clearly demonstrated that head position affected the anatomic relationships between the relevant structures--the hyoid apparatus and the larynx--before and after surgery," said McCluskie.

Based on these results, the authors attest that, "A standardized head position is necessary to accurately assess the efficacy of the tie-forward procedure. The extended head position appears to be the most appropriate choice for pre- and post-operative radiographic assessment of the tie-forward."

The study, "Effect of head position on radiographic assessment of laryngeal tie-forward procedure in horses," was published in the October 2008 edition of the journal Veterinary Surgery.

About the Author

Stacey Oke, DVM, MSc

Stacey Oke, MSc, DVM, is a practicing veterinarian and freelance medical writer and editor. She is interested in both large and small animals, as well as complementary and alternative medicine. Since 2005, she's worked as a research consultant for nutritional supplement companies, assisted physicians and veterinarians in publishing research articles and textbooks, and written for a number of educational magazines and websites.

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