Multiple forms of DUAO occurred pre-LP and additional forms often developed post LP. Post LP the degree of arytenoid cartilage abduction at rest was useful to predict the degree of abduction during exercise.

Summary The efficacy of partial arytenoidectomy was assessed in 6 Standardbred horses, with surgically induced laryngeal hemiplegia, at rest (Period A) and during exercise at speeds corresponding to maximum heart rate (Period C) and 75% of maximum heart rate (Period B). Peak expiratory and inspiratory airflow rate (PEF and PIF), and expiratory and inspiratory transupper airway pressure (PUE and PUI) were measured and expiratory and inspiratory impedance (ZE and ZI) were calculated. Simultaneously, tidal breathing flow‐volume loops (TBFVL) were acquired using a respiratory function computer. Indices derived from TBFVL included airflow rates at 50 and 25% of tidal volume (EF50, IF50, EF25. and IF25) and the ratios of expiratory to inspiratory flows. Measurements were made before left recurrent laryngeal neurectomy (baseline), 2 weeks after left recurrent laryngeal neurectomy (LRLN) and 16 weeks after left partial arytenoidectomy coupled with bilateral ventriculectomy (ARYT). After LRLN, during exercise Periods B and C, Z1 and the ratio of EF50/IF50 significantly increased and PIF, IF50 and IF25 significantly decreased from baseline values. At 16 weeks after ARYT, Z1 returned to baseline values during Periods B and C. Although PIF, IF50, IF25, PEF/PIF, and EF50/IF50 returned to baseline values during Period B, these indices remained significantly different from baseline measurements during Period C. After ARYT, TBFVL shapes from horses during Period C approached that seen at the baseline evaluation. Partial arytenoidectomy improved upper airway function in exercising horses with surgically induced left laryngeal hemiplegia, although qualitative and quantitative evaluation of TBFVLs suggested that some flow limitation remains at near maximal airflow rates. These results indicate that, although the procedure does not completely restore the upper airway to normal, partial arytenoidectomy is a viable treatment option for failed laryngoplasty and arytenoid chondropathy in the horse.

Multiple DUAO in association with abnormal exercising respiratory noise was a common finding in horses examined for poor performance. This study highlights the importance of OGE in accurately diagnosing the nature of DUAO associated with poor performance.

Summary Subepiglottic cysts (SECs) are an infrequent cause of upper respiratory tract noise and exercise intolerance in horses. They may also be associated with no clinical signs and be an incidental finding during routine upper airway endoscopy. The aim of this study was to assess the effect on performance of horses undergoing surgical removal of SECs. The case records of 15 horses (1995–2009) diagnosed with SECs were retrieved. Eleven (73%) of the 15 horses included in the study were Thoroughbred racehorses. Eleven (73%) of the 15 horses had no preoperative clinical signs related to the SECs, with the remaining 4 (27%) having a respiratory noise (n = 4), nasal discharge (n = 1), difficulty swallowing (n = 1) or a cough (n = 1). Endoscopic examination in the standing horse was diagnostic in 93% (n = 14) of horses. Nine (82%) of the 11 Thoroughbred horses were yearlings, of which only one horse (11%) presented with clinical signs consisting of a respiratory noise and nasal discharge. Four of the 11 (36%) Thoroughbred horses were found to have concurrent epiglottic entrapment. Surgical removal was successful in all cases. Eight of the 11 (73%) Thoroughbred horses in this study raced following SEC removal. The majority of SECs are identified during routine endoscopic examinations and are not associated with clinical signs. The prognosis following surgical removal of SECs is good and future performance does not appear to be affected.

Idiopathic haemarthrosis should be considered a differential for acute and recurrent joint related lameness and effusion. Recurrence appears not uncommon and the use of intra-articular (90) Y and MPA in conjunction with a conservative management treatment protocol warrants further evaluation.