Optimal tension, position, and number of prostheses required for maximum rima glottidis area after laryngoplasty.

OBJECTIVES: To evaluate the effect of 3 laryngeal prostheses alone or in combination on rima glottidis area in horses. STUDY DESIGN: Experimental randomized design. SAMPLE POPULATION: Cadaveric equine larynges (n = 22). METHODS: Three prostheses were preplaced in each of 14 larynges. Rima glottidis area was measured after loading each suture in 5 Newton (N) increments from 0 N to 35 N. In 8 larynges, the 3 prostheses were tied alone or in combination at a fixed load of 15 N and rima glottidis area measured. RESULTS: Rima glottidis cross-sectional area increased as the load on each prosthesis increased with maximum area reached at 20 N for each prosthesis. At a fixed load of 15 N, tying 2 and 3 prostheses in combination resulted in a larger rima glottidis cross-sectional area than achieved with each prosthesis alone. CONCLUSIONS: A combination of 2 or 3 prostheses tied at a fixed load of 15 N optimized rima glottidis cross-sectional area irrespective of the anatomic location of the prosthesis.

Effect of age and prostheses location on rima glottidis area in equine cadaveric larynges.

OBJECTIVE: To determine the effect of horse age and laryngeal prosthesis location on rima glottidis area in cadaveric larynges. STUDY DESIGN: Experimental study. ANIMALS: Cadaveric equine larynges (n = 40). METHODS: Specimens were grouped by age: group 1, ≤5 years (n = 18); group 2, >5 to ≤10 years (n = 12); group 3, >10 years (n = 10). A cranial prosthesis was placed through the dorsal cricoid spine at 70% of the distance of the total cricoid length measured from the caudal rim. A dorsal prosthesis was placed through the caudal rim of the cricoid on the dorsal midline. A lateral prosthesis was placed 1.5 cm lateral to the dorsal prosthesis. All prostheses passed through the muscular process. Rima glottidis area was determined after progressively tightening each suture in 5 N increments from 0 N to 35 N using a tensiometer. RESULTS: There was no significant effect of age on the area of the rima glottidis at any load for any of the three prosthesis locations. CONCLUSIONS: Age did not affect the area of the rima glottidis when prostheses were loaded between 5 N and 35 N.