Surgical advancement of the larynx (laryngeal tie-forward) as a treatment for dorsal displacement of the soft palate in horses: a prospective study 2001-2004.

The research examines the effectiveness of the ‘laryngeal tie-forward’ surgical procedure in treating horses with dorsal displacement of the soft palate (DDSP), an exercise-induced condition. The study concludes that the surgery, which alters the position of the larynx, improves performance in 80-82% of treated horses and has potential as an alternative DDSP treatment.

Objective and Methodologies

• The primary goal of this research was to study the impact of the ‘laryngeal tie-forward’ surgical procedure on horses suffering from dorsal displacement of the soft palate (DDSP), a condition that adversely affects their performance. The authors were aiming to confirm whether the procedure prevents or delays the onset of DDSP during exercise.
• For the study, the researchers took a sample of 116 horses, mostly racehorses, with naturally occurring exercise-induced DDSP.
• Each horse underwent the ‘laryngeal tie-forward’ surgery. Before and after the operation, the researchers recorded the relative locations of the thyroid and cricoid cartilage in relation to the back of the basihyoid bone.
• They maintained follow-ups through phone communications with the horses’ trainers, owners, or referring veterinarians. They also tracked the performance index and earnings of the horses using race records.

Findings

• Before the surgery, the median distance from the rear of the basihyoid bone to the front of the thyroid cartilage was 3.5 cm. Upon postoperative examination, they found that the thyroid cartilage had moved about 4 cm forward, positioning the larynx rostrally and dorsally compared to presurgical placements.
• Out of 98 horses with available follow-up records, 87% showed improved performance, 12% remained unchanged, and performance worsened in 2% of them. In 20 horses where DDSP was confirmed with treadmill videoendoscopy, 80% had significantly better performance index and earnings, providing statistical significance at P = 0.007.
• When considering the entire population, a significant improvement in performance index and earnings was evident in 82% of the horses after surgery (P = 0.0001).

Conclusions and Future Directions

• The research concluded that adjusting the larynx’s position improves the performance of 80-82% of horses affected by naturally-occurring DDSP, suggesting the ‘laryngeal tie-forward’ surgery as a potential alternative treatment for DDSP.
• However, the authors also stress that more practical experience may be required with this procedure before its broad implementation in horses clinically diagnosed with DDSP.