Long-term survey of laryngoplasty and ventriculocordectomy in an older, mixed-breed population of 200 horses. Part 1: Maintenance of surgical arytenoid abduction and complications of surgery

Reasons for performing study: Laryngoplasty (LP) is currently the most common surgical treatment for equine laryngeal paralysis, however, there have been no reports quantifying the degree of retention of arytenoid abduction following L P. ADitionally, the complications of LP have been poorly documented. Objectives: To record the degree of arytenoid abduction retention following LP and to accurately document all complications of surgery. Methods: A study (1986-1998) of 200 horses of mixed breed and workload, median age 6 years (prospective 136 cases and retrospective 64 cases) undergoing LP (using 2 stainless steel wires) and combined ventriculocordectomy was undertaken; 198 owners completed questionnaires, a median of 19 months following surgery. The degree of arytenoid abduction achieved was endoscopically, semi-quantitatively evaluated using a 5-grade system, at 1 day, 7 days, and 6 weeks after surgery. Results: On the day following LP, 62% of horses had good (median grade 2) arytenoid abduction, 10% had excessive (grade 1), and 5% had minimal (grade 4) abduction (overall - median grade 2). Due to progressive loss of abduction, moderate (median grade 3, range 1-5) abduction was present overall at 1 and 6 weeks after LP. Further surgery was required to re-tighten prostheses in 10% of cases with excessive loss of abduction, or to loosen prostheses in 7% of horses which had continuing high levels of LP abduction and significant post operative dysphagia. LP wound problems (mainly seromas and suture abscesses) were reported to last <2 weeks in 9% of cases, <4 weeks in 4% and >4 weeks in 4%. The (partially sutured) laryngotomy wounds discharged post operatively for <2 weeks in 22% of cases, <4 weeks in 7% and for >4 weeks in 2%. Coughing occurred at some stage post operatively in 43% of cases and its presence correlated significantly with the degree of surgical arytenoid abduction. This coughing occurred during eating in 24% of cases and was not associated with eating (or dysphagia) in the other 19% of cases. Chronic (>6 months duration) coughing occurred in 14% of cases, but appeared to be due to intercurrent pulmonary disease in half of these horses. Conclusions: Suturing the cricotracheal membrane allows most laryngotomy wounds to heal quickly. Laryngoplasty wound problems were of little long-term consequence when stainless steel wire prostheses were used. Potential relevance: A significant loss of LP abduction occurs in most horses in the 6 weeks following surgery and efforts should be made to find ways to prevent such loss. However, excessive LP abduction is associated with post operative dysphagia and coughing.