It is quite common for a horse to be scoped because of coughing, nasal discharge or simply because of poor performance. As a result of this examination it is also common to be presented with a diagnosis of ‘pharyngitis’ ( inflammation of the pharyngeal airway).

Pharyngitis often follows a respiratory infection ( viral or bacterial). In these cases the treatment of choice are topical anti-inflammatory medications and in selected cases antibiotics with an appropriate rest period. The pharyngitis should then resolve.

However in some cases following resolution and associated improvement in training there is a recurrence weeks or months later. This recurrence is often at a time when work load is increased either just prior to racing or after only one or two race starts. In these cases the pharyngitis may well be ‘secondary’ to, or a ‘symptom’ of a primary upper airways dysfunction. The most probable dysfunction is Palatal Instability (PI).

The incidence of PI increases with increases in respiratory (training intensity) demand. With PI bacteria, saliva and feed material that are part of normal oral (mouth) contents can be drawn into the airways and these then trigger airways inflammation ( pharyngitis & tracheitis ). In these cases treatment with anti-inflammatory and antibiotic medications will only give temporary relief. 

Instead of medical treatments your vet should carry out either treadmill or preferably ‘overground’ endoscopy. If PI with or without DDSP is diagnosed then surgery is indicated. 

TREATMENT - for chronic or repeated episodes of pharyngitis associated with PI.

There are only two surgical approaches that attempt to deal with this issue directly.

( Other procedures may ‘indirectly’ affect function at the OPS)

The two procedures are (i) ‘Ahern Procedure’ ( Oral Palatopharyngoplasty)

                                       (ii) ‘Soft Palate firing’ ( Thermal Palatoplasty)

Both these procedures attempt to tighten the ‘valve’ that forms the first part of the OPS. This valve is referred to as the Isthmus Faucium. 

There are however subtle but important differences between the two approaches.

Thermal Palatoplasty -

Firing causes an increase in tension of the superficial tissues of the underside of the soft palate. As a result the circumference of the Isthmus is reduced. This can improve the seal but also reduces the size of the cavity that houses the tongue. Improvement is often said to be temporary ( several months only) which may be explained by the fact that the more important tissues to tense are the ‘deep’ tissues of the palate which support the action of the ‘natural’ tensing mechanism which is the ‘broad tendon’ or aponeurosis. With firing these tissues are only secondarily tensed by the inflammatory process which accompanies the firing. As the inflammation settles (6-8 weeks) this effect is lost and symptoms can return. 

Oral Palatopharyngoplasty -

This surgical technique has evolved over the last 25 years with the present form being described as the ‘Modified Ahern Procedure’. The surgery has two components.

  1. a.Tension Palatoplasty (TPP) with ‘Tension Release’ incisions. This creates tension in the deep tissues of the mid and rostral soft palate which is the region tensed by the broad tendon. The tension release incisions maintain the aperture at the Isthmus so the tongue is not squeezed out of the back section of the mouth (oropharynx). This increase in tension should be permanent.

  2. b.Subepiglottal mucosae stripping. This is performed to improve stability at the other valve that functions to maintain the OPS. The Intrapharyngeal Ostium.

Note (i):- both procedures can be repeated at later dates to further increase tension.  Approximately 1 in 4 OPP’s undergo maximum tensing at 1 to 3 years after the original procedure. Soft Palates are often repeat ‘fired’ up to 3 times in some instances.