Page 677 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

652 CHAPTER 3

VetBooks.ir the airway, to flatten the epiglottis. This is usually established that the epiglottis does not hold the soft
palate down, and DDSP is the result of palatal weak-
observed as a precursor to DDSP when endoscopic
examination is performed during exercise. The
the epiglottis was shorter in horses with a history
findings of either a flaccid epiglottis or soft palate ness, not epiglottic. Initial studies did suggest that
at rest are of no diagnostic value. It is reasonably of DDSP, but more recently other studies have not
well established that changes at rest are a poor pre- verified this finding.
dictor of changes at exercise. Thus, a horse with a
flaccid epiglottis at rest may perform perfectly well Aetiology/pathophysiology
at exercise. Epiglottic hypoplasia is believed to be a congeni-
tal condition. An epiglottis that measures less than
Management 5.5 cm in a Thoroughbred (normal 8–9 cm) is con-
The treatment for epiglottic flaccidity is aug- sidered to be hypoplastic.
mentation with polytetrafluoroethylene (Teflon)
paste. A ventral laryngotomy is performed and the Clinical presentation
epiglottis retroverted by traction on the aryepiglot- The clinical presentation is intermittent DDSP and/
tic folds. The copious subepiglottic mucosa is then or epiglottic entrapment.
injected with polytetrafluoroethylene paste, taking
care to lay the paste down in a line from the base of Differential diagnosis
the epiglottis to the apex. The differential diagnoses include all other causes of
This surgery is commonly used as one of a series DDSP, and in turn all other causes of upper airway
of procedures for the treatment of DDSP, rather obstruction. Epiglottic flaccidity is the primary dif-
than a specific treatment for epiglottic flaccid- ferential diagnosis for an epiglottic cause of DDSP.
ity alone. Published results suggest the surgery is
quite successful; however, it is widely accepted to be Diagnosis
another surgery for dorsal displacement of the soft The diagnosis is initially made by endoscopic
palate, associated with a similar success rate to most examination, but it should be confirmed by radi-
other procedures. ography. A lateral radiograph of the pharynx and
larynx is taken with a spherical radiopaque object
Prognosis of known dimensions taped to the horse in the mid-
In published studies, 73% of Thoroughbreds and line (Fig. 3.97). A comparison of the actual and
53% of Standardbreds showed improved racing measured dimensions of the object gives an accu-
performance after surgery. Complications of exces- rate measurement of radiographic magnification.
sive granulation and abscess formation have been The length of the epiglottis can then be measured
reported in some cases post surgery. The progno- from the basihyoid to the tip of the epiglottis on
sis for epiglottic flaccidity generally is considered to the radiograph and its true length calculated using
be good – most horses have improved endoscopic the magnification factor.
appearance of the pharynx with increasing maturity.
Management
EPIGLOTTIC HYPOPLASIA There is no effective surgical solution to lengthen
the epiglottis. The length of the epiglottis is an inci-
Definition/overview dental finding unrelated to DDSP.
Epiglottic hypoplasia is another controversial condi-
tion that may not exist. Similar to epiglottic flaccid- Prognosis
ity, the hypothesis is that the epiglottis is crucial in Genuine epiglottic hypoplasia has a poor progno-
maintaining the soft palate in a normal subepiglottic sis. Otherwise the prognosis is that of DDSP (i.e.
position; therefore, a short epiglottis is more likely approximately 60% of horses will improve, regard-
to be associated with DDSP. It is now definitively less of treatment).