Effect of head position on radiographic assessment of laryngeal tie-forward procedure in horses.
Authors: McCluskie Laura K, Franklin Samantha H, Lane J Geoffrey, Tremaine W Henry, Allen Katherine J
Journal: Veterinary surgery : VS
Summary
# Editorial Summary: Head Position and Laryngeal Tie-Forward Assessment Laryngeal tie-forward is a surgical intervention for horses with palatal dysfunction, but accurate post-operative radiographic evaluation has lacked standardisation. McCluskie and colleagues examined nine adult horses with palatal dysfunction, taking left lateral radiographs of the larynx before and after surgery across three controlled head positions (flexed at 90°, neutral at 100°, and extended at 115°), measuring the distance between the thyrohyoid bone and thyroid cartilage to assess laryngeal repositioning. Pre-operatively, head position significantly influenced hyoid apparatus and laryngeal relationship, with maximum separation occurring in extension; however, post-operatively, all three positions yielded comparable measurements, suggesting the surgical fixation stabilises this relationship. Critically, the flexed position failed to demonstrate significant pre- to post-operative differences, rendering it unsuitable for outcome assessment, whilst neutral and extended positions clearly showed post-operative change. For practitioners evaluating laryngeal tie-forward success, these findings argue for standardised radiographic positioning using head extension to accurately document surgical effect—particularly important given that inadequate laryngeal advancement can compromise airway function during exercise. Adopting a consistent extended head position across cases will improve comparison of individual cases, facilitate meaningful audit of surgical outcomes, and help identify which horses require re-evaluation or alternative interventions for persistent upper airway obstruction.
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Practical Takeaways
- •Always position the horse's head in extension (115°) when taking radiographs to assess laryngeal tie-forward surgery — this is the only reliable position for detecting whether the procedure has successfully repositioned the larynx
- •Avoid flexed head positions for postoperative assessment as they may falsely suggest the surgery failed or succeeded due to positioning artifact rather than actual surgical effect
- •Standardize your radiographic technique using extended head position to enable meaningful comparison between pre- and postoperative films and between cases
Key Findings
- •Head position significantly affects the radiographic relationship between the hyoid apparatus and larynx preoperatively, with maximum distance in extension (115°)
- •Postoperative measurements were unaffected by head position, showing consistency of the surgical repair across positions
- •Flexed head position (90°) failed to detect postoperative changes in laryngeal position, making it unsuitable for surgical assessment
- •Extended head position (115°) is the only position reliably demonstrating pre- to postoperative differences in laryngeal tie-forward procedures