The objective of this study was to assess the effect of head position on relative position of the larynx and hyoid apparatus in horses with palatal dysfunction, and to define a standard position for radiographic assessment of laryngeal tie-forward.
Nine adult horses with palatal dysfunction were included.
Left lateral radiographs of the larynx were obtained pre and postoperatively for 3 different head positions (flexed=90°; neutral=100°; extended=115°).
Distance between thyrohyoid bone and thyroid cartilage was measured. Data were analyzed to investigate differences between head positions, and to compare differences between pre- and postoperative measurements.
Results: Head position had a significant effect on relative position of the larynx and hyoid apparatus preoperatively.
There was no significant difference in postoperative measurements of the 3 head positions.
A significant difference between pre- and postoperative measurements was found with the head in the neutral or extended position whereas there were no significant differences between pre- and postoperative measurements using the flexed position.
Conclusions: Head position affects the relationship between the hyoid apparatus and larynx preoperatively, with greatest distance occurring when the head is extended.
In a flexed position, it is not possible to ascertain whether laryngeal position has changed postoperatively.
Thus, a standardized head position is necessary when assessing the laryngeal tie-forward procedure radiographically. An extended head position is most useful for this assessment.
Source: LAURA K. McCLUSKIE, SAMANTHA H. FRANKLIN, J. GEOFFREY LANE, W. HENRY TREMAINE, KATHERINE J. ALLEN (2008): Effect of Head Position on Radiographic Assessment of Laryngeal Tie-Forward Procedure in Horses. In: Veterinary Surgery
Volume 37 Issue 7, Pages 608 - 612
|