Fernando Bulnes

and 6 more

Background: The paracondylar process is of clinical interest due to its proximity to anatomical structures involved in vital functions. There are limited reports describing abnormalities affecting the paracondylar process (PCP), with traumatic fractures being the most prevalent pathology. Affected horses can present with a variety of signs including headshaking, facial paralysis and/or poor performance. In almost all cases reported in the literature to date, computed tomography has been used to diagnose a PCP fracture. Objectives: The aim of this study was to develop a radiographic technique for imaging the PCP, to determine the optimum radiographic projection angle and trial its use in standing sedated horses. Study design: Pilot study conducted in 10 standing sedated horses. Methods: Three tangential radiographs of the left and right paracondylar processes at 5º, 15º and 20º to the transverse plane were obtained in 10 standing sedated horses. Three blinded observers independently ranked each of the three images for clarity of viewing the PCP. The radiographic projection allowed imaging of the ventral portion of the PCP while avoiding superimposition of other osseous structures. Results: The highest grades were obtained for radiographs with a 5º angle from the transverse plane, and the lowest grades were obtained for a 20º angle. Main limitations: Complex anatomy of the PCP with superimposition of osseous and soft tissue structures. Conclusions: The radiographic technique for the PCP can be safely performed in standing, sedated horses. It is suitable for implementation in general veterinary practice before considering referral for advanced imaging techniques in horses presenting with headshaking or facial paralysis.

Christopher Baldwin

and 2 more

Background: There is no objective information reporting the effect of unilateral laser ventriculocordectomy (VeC) on arytenoid abduction or stability. Objectives: To evaluate arytenoid stability and abduction in horses with severe recurrent laryngeal neuropathy (RLN) before and after unilateral laser VeC. Study design: Prospective study in clinically affected client-owned horses. Methods: Sample size calculations indicated ≥7 horses were required. Horses with grade C or D exercising laryngeal function that underwent unilateral laser VeC were included. Exercising endoscopy was performed before and ≥6 weeks after left-sided laser VeC. Arytenoid stability at maximal exercise was calculated by measuring the left-to-right quotient angle ratio (LRQ) of the corniculate processes at the points of maximal arytenoid abduction (expiration) and maximal arytenoid collapse (inspiration). For each horse, means of measurements obtained for four breaths pre- and post-operatively were used for statistical analysis. Results: Eight horses were included: 5 grade C and 3 grade D laryngeal function. The difference in LRQ between inspiration and expiration was lower post-operatively (median 0.039; interquartile range [IQR] 0.032-0.047) compared to pre-operatively (median 0.158; IQR 0.083-0.249; p=0.01) confirming the left arytenoid was more stable following unilateral laser VeC. The degree of improvement was significantly greater for grade D horses compared to grade C horses (p=0.04). The LRQ measured on maximal abduction was also lower post-operatively (median 0.467; IQR 0.444-0.506) compared to pre-operatively (median 0.578; IQR 0.554-0.655; p=0.02) indicating the left arytenoid was less abducted following surgery. Main study limitations: The sample size was small, no racehorses were included and post-operative assessment was conducted at a variable time after surgery. Conclusion: Unilateral laser VeC in grade C and D RLN-affected horses results in slightly reduced left arytenoid abduction but increased arytenoid stability.