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Dynamic Respiratory Endoscopy / Exercise Endoscopy / Overground Scope 


Endells is able to offer you dynamic endoscopy, bringing the most advanced and modern technology to your premises where fast work may be observed such as on a gallops, or here at the hospital.


Until recently, most disorders of the upper respiratory tract were identified with a clinical examination of the horse, watching and listening to the horse while exercising and then by visualising using standing endoscopic examination.  The limitations of this traditional method are that many URT problems are only apparent at exercise, leading to them being missed on a standing scope. 


Does my horse need a overground scope?

Exercise endoscopy is used in horses with a history of poor performance, fatigue and respiratory noise at exercise. If you feel your horse is showing any of these signs, please consult one of our vets who will be able to advise you.

What happens if my horse has an overground scope?

Overground scoping can be done at your yard, in the place where your horse is usually exercised. The flexible endoscope is placed up your horses’ nose until the larynx can be visualised. The scope is then clipped on to a special bridle, and is joined to a battery pack and the computer which sit over the horses withers. The entire process is very well tolerated by most horses and then allows us to fully visualise the larynx in all situations, from at rest, to full gallop and in the recovery period. The footage is instantly available to view as the horse is in action.

What does the normal larynx look like?
normal larynx

RA = right arytenoid cartilage

LA = left arytenoid cartilage

RAEF = right aryepiglottic fold 

LAEF = left aryepiglottic fold

T = trachea

VC = vocal cords

E= epiglottis

SP = soft palate

What conditions can we see on overground endoscopy?
Left laryngeal hemiplegia/recurrent laryngeal neuropathy / ‘roarers’: 
Left laryngeal hemiplegia / recurrent laryngeal neuropathy ('roarers')

This condition is linked to poor performance and early fatigue, as the left arytenoid cartilage cannot fully abduct, or in some cases, collapses completely. This effect has been likened to ‘breathing through a straw’ and is often characterised by a ‘roaring’ or ‘whistling’ noise at exercise.

The disease is graded from 1-4, where 1 is normal and 4 is where there is no movement of the left arytenoid cartilage. This is where overground endoscopy is essential, as the larynx can appear normal at rest but grossly abnormal at exercise.                           

Here you can see the left arytenoid cartilage collapsing – symmetry has been lost from the larynx and there is obstruction of the trachea.

Dorsal displacement of the soft palate (‘gurglers’): 
Dorsal displacement of the soft palate ('gurglers')

Dorsal displacement of the soft palate (DDSP) intermittently occurs during or after exercise and can be performance limiting, especially after intense exercise. The soft palate flips dorsally, covering the epiglottis and partially obstructing the trachea. Horses may be seen to swallow profusely as they try to replace the palate below the epiglottis, and they may make a gurgling noise on expiration. It can be a normal finding at rest, where it does not cause a problem to the horse. It is important to know if it also occurs at exercise, as this is when you can see clinical signs of tracheal obstruction, such as slowing down or pulling up and respiratory noise.

Here you can see how the soft palate has lifted up, covering all of the larynx except for the very tips of the arytenoid cartilages. The trachea and the epiglottis have both been obscured from view. (The horse in the video also has axial deviation of the aryepiglottic folds for the eagle-eyed amongst you!)

Axial deviation of the aryepiglottic folds: 
Axial deviation of the aryepiglottic folds

The aryepiglottic folds sit on either side of the larynx, and can collapse inwards at exercise if there is excess tissue, obstructing the trachea. This can cause a ‘whistling’ noise in the exercising horse, as the airway becomes obstructed.   

Here you can see the aryepiglottic folds collapsing into the airway forming an hourglass shape.

Vocal cord collapse: 
Vocal cord collapse

The vocal cords can also collapse into the airway, causing obstruction.

Here you can see the vocal folds have both collapsed inwards into the airway

Arytenoid chondritis: 
Arytenoid chondritis

This is an inflammatory condition of the arytenoid cartilages which can result in exercise intolerance and respiratory noise. If there is sufficient thickening and damage the cartilages can start to cause obstruction of the trachea. 

Here you can see buds of granulation tissue on the arytenoid cartilages that are starting to protrude into the trachea (turquoise arrows).   You can also see areas of inflammation (green circles).


My horse has been diagnosed with an upper respiratory tract problem – what can I do about it?


Here at Endells we have facilities for both ‘sharp’ surgery under general anaesthesia, and laser surgery done standing with sedation and local anaesthetic. Once your horse has been diagnosed, your vet will be able to have a full discussion of treatment options for your particular case.

If you would like any more information about our dynamic overground scoping, please contact the surgery to discuss it with one of our vets.