Page 159 - Manual of Equine Field Surgery

Dorsal Displacement of the Soft Palate
airway compromise during exercise but can
recover quickly when the horse is allowed to
swallow to replace the palate i11 the correct posi-
tion. During clinical examination, the palate may
not displace unless specific conditions, such as the
type of tack used and the head position used
during performance, can be duplicated. Unless the
specific conditions are duplicated, the "noise"
reported by the owner or trainer will not be noted
and the airway will generally appear completely
normal on endoscopic examination at rest or after
exercise (Figure 25-14). Endoscopic examination
while the horse is working on a high-speed tread-
mill, ideally with the same tack and head position
that exist when the DDSP typically occurs, is fre-
quently the only way to directly make the diagno-
sis. 21
DDSP may occur secondary to other airway
abnormalities that cause turbulent airflow, in-
creased negative airway pressure, or to signifi-
cant upper airway inflammation. These common
airway abnormalities include laryngeal hemiple-
gia, epiglottic entrapment, guttural pouch dis-
orders, and pharyngeal lymphoid hyperplasia.
Therapy to address these potential primary prob-
lems is warranted before proceeding with any of
the surgical options discussed here.
REFERENCES
1. Mcilwraith CW, Turner S: Myectomy of the ster-
nohyoid, sternothyroid, and omohyoid muscles. In
Mcllwraith CW, Turner S, editors: Equine surgery
advanced techniques, Philadelphia, 1987, Lea &
Febiger.
2. Harrison IW, Raker CW: Sternothyrohyoideus
myectomy in horses: 17 cases (1984-1985), J Am
Vet Med Assoc 193:1299, 1988.
3. Shappell KK, Caron JP, Stick JA, et al: Staphylec-
tomy for treatment of dorsal displacement of the
soft palate i11 two foals, J Am Vet Med Assoc
195:1395, 1989.
4. Anderson JD, Tulleners EP, Iohnston JK, et al: Ster-
nothyrohyoideus myectomy or staphylectomy for
treatment of intermittent dorsal displacement of
the soft palate iI1 racehorses: 209 cases (1986-1991),
J Am Vet Med Assoc 206:1909, 1995.
5. Duncan DW: Retrospective study of 50 Thorough-
bred racehorses subjected to radical myectomy
Sl1rgery for treatment of dorsal displacement of the
soft palate, Proc Am Assoc Equine Pract 43:237,
1997.
155
6. Llewellyn HR, Petrowitz AB: Sternothyroideus
myotomy for the treatment of dorsal displacement
of the soft palate, Proc Ani Assoc Equine Pract
43:239, 1997.
7. Robertson JT: Dorsal displacement of the soft
palate. In White NA II, Moore JN, editors: C·urrent
techniques in equine surgery and lameness, Philadel-
phia, 1998, WB Saunders.
8. Holcombe SJ, Ducharme NG: Pharynx. In A11er JA,
Stick JA, editors: Equine surgery, ed 2, Philadelphia,
1999, WB Saunders.
9. Adams SB, Fessler JF: Sternothyrohyoideus
myectomy. In Adams SB, Fessler JF, editors:
Atlas of equine surgery, Philadelphia, 2000, WB
Saunders.
10. JagerHauer K, Lutkefels E, Deegen E, et al: Experi-
mental study 011 transendoscopic laser surgery of
dorsal displacement of the soft palate in horses,
Tierarztliche Praxis Ausgabe Grosstiere Nutztiere
31:18, 2003.
11. Ducharme NG: Treatment considerations for
DDSP, Proc ACVS Vet Syrnp 13:210, 2003.
12. Stick JA: Soft palate displacement: treatment
options, Proc ACVS Vet Symp 13:189, 2003.
13. Tate LP, Sweeney CL, Bowman KF, et al: Transendo-
scopic Nd:YAG laser surgery for treatment of
epiglottal entrapment and dorsal displacement
of the soft palate in the horse, Vet Surg 19:356,
1990.
14. O'Rielly JL, Beard WL, Renn TN, et al: Effect of
combined staphylectomy and laryngotomy on
upper airway mechanics in clinically normal
horses, Am J Vet Res 58:1018, 1 997.
15. BonenClark G, Bryant J, Hernandez J, et al:
Sternothyroideus tenectomy or sternothyroideus
tenectomy with staphylectomy for the treatment of
soft palate displacement, Proc Am Assoc Equine
Pract 45:85, 1999.
16. Adams SB, Fessler JF: Epiglottic augmentation and
staphylectomy. In Adams SB, Fessler JF, editors:
Atlas of equine surgery, Philadelphia, 2000, WB
Saunders.
1 i. Hogan PM, Palmer SE, Congelosi M: Transendo-
scopic laser cauterization of the soft palate as an
adjunctive treatment for dorsal displacement in
the racehorse, Proc Am Assoc Equine Pract 48:228,
2002.
18. Barakzai SZ, Iohnson VS, Baird DH, et al: Assess-
ment of the efficacy of composite surgery for the
treatment of dorsal displacement of the soft palate
in a group of 53 racing Thoroughbreds ( 1990-1996),
Equine Vet J 36:175, 2004.
19. Smith JJ, Embertson RM: Sternothyroideus
Myotomy, staphylectomy, and oral caudal soft
palate photothermoplasty for treatment of dorsal
displacement of the soft palate in 102 Thorough-
bred racehorses, Vet Surg 34:5, 2005.