A Modified Laryngeal TieForward Procedure Using Metallic Implants

A Modified Laryngeal Tie-Forward Procedure Using Metallic
Implants for Treatment of Dorsal Displacement of the Soft
Palate in Horses
Fabrice Rossignol1 , DVM, Diplomate ECVS, Emilie Ouachée1 , DVM, and Karl Josef Boening2 , DVM,
Diplomate ECVS
1
Clinique de Grosbois, Boissy Saint Léger, France and 2 Tierklinik Telgte, Telgte, Germany
Corresponding Author
Emilie Ouachée, DVM, Clinique de Grosbois,
Domaine de Grosbois, 94470 Boissy Saint
Leger, France
E-mail: [email protected]
Received November 2010
Accepted January 2012
DOI:10.1111/j.1532-950X.2012.01001.x
Objective: To describe a modified laryngeal tie-forward procedure (LTFP) using
metallic implants.
Study Design: Retrospective case series.
Population: Twenty-seven horses (including 24 race horses) with dorsal displacement of the soft palate (DDSP) or palatal instability (PI) diagnosed using highspeed treadmill endoscopy (n = 15), history and resting examination (n = 8), or
dynamic endoscopy over ground (n = 4).
Methods: All horses underwent the modified LTFP. Modifications of the surgical
procedure consisted in the use of 3 metallic stents called Suture ButtonTM through
which the sutures are threaded and in a tying technique that involved a single knot
connecting left and right suture loops (versus tying each separately). Lateral radiographs were taken 24 hours after surgery. Follow-up was obtained by telephone
communication with trainers or owners.
Results: Surgery was performed without complications on all horses. The 3 metallic buttons were clearly visible on the postoperative radiographic examination. No
evidence of suture breakage was observed 24 hours postoperatively based on
radiographs.
Conclusion: In other aspects, this technique is not very different from that originally described by Ducharme et al; it is an innovation that could offer some
advantages to the surgeons and increase suture resistance to pullout from the thyroid cartilage. Our technique was used without complication in a small group of
horses and return to performance may be similar to the original technique.
Dorsal displacement of the soft palate (DDSP), with a reported prevalence of 10–20%,1 causes upper airway obstruction during exercise, with mouth breathing and a
sudden reduction in speed. Most affected horses make an
abnormal gurgling noise (62%) during DDSP.2 Stability of
the equine upper airway during exercise may be mediated
through the hypoglossal nerve,3 but the cause of DDSP
remains unknown.
Surgical techniques to prevent caudal retraction of the
larynx have a success rate of ∼58–73% compared with
60% reported for conservative treatment.4 A laryngeal tieforward procedure (LTFP), whereby sutures are placed in
the orientation of thyrohyoid muscles appears to stabilize
the soft palate during exercise,5 with 80–82% of race horses
having a successful outcome.6 Horses with DDSP that had
LTFP are as likely to race postoperatively as matched controls (66% of the horses with a definitive diagnosis raced
Work done at Clinique de Grosbois, Boissy Saint Leger, France.
Presented in part at the 11th Congress on Equine Medicine and
Surgery, Geneva, Switzerland, December 15–17, 2009.
postoperatively and 90% of those with a presumptive diagnosis) achieve earnings similar to preoperative levels and to
those of matched controls.7
Suture pullout from laryngeal cartilage is a common
problem after upper airway surgery in horses, although reportedly less common after LTFP than after laryngoplasty.8
Metallic implants have been used in prosthetic laryngoplasty to minimize the likelihood of suture pullout.9 Because of clinical experience with suture pullout from the
thyroid cartilage in young Thoroughbreds after LTFP, we
evaluated a modified technique for LTFP using the same
metallic implants. In a in vitro study to be published (Boening JK, personnal communication), the authors compared
resistance before thyroid cartilage failure between a single loop (described in the original technique5 ) and a Suture
R
ButtonTM (Arthrex
, Karlsfeld, Germany; Fig 1). A significantly higher force was required for thyroid cartilage failure
with a Suture ButtonTM . Postoperative stability of the prosthesis is difficult to guarantee, and although radiographic7
and ultrasonographic8 techniques for assessment have been
C Copyright 2012 by The American College of Veterinary Surgeons
Veterinary Surgery 00 (2012) 1–4 1
Modified Laryngeal Tie-Forward Technique
Rossignol et al.
Figure 1 (A) Custom bent Suture ButtonTM (Landanger, Chaumont,
R
France); (B) 3.5-mm Suture ButtonTM (Arthrex
, Karlsfeld, Germany).
reported, they can be challenging in practice. Use of suture
buttons for LTFP facilitates radiographic assessment of the
position of the hyoid bone in relation to the thyroid cartilage after suture tightening. Our purpose was to describe
our technique for a modified LTFP using metallic implants.
MATERIALS AND METHODS
Horses
Horses (n = 27) evaluated for DDSP (from August 2008
to May 2010) were considered as the candidates for LTFP;
15 had DDSP diagnosed using high-speed treadmill endoscopy (11 horses had DDSP and 4 horses had severe
palatal instability [PI]), and 4 using dynamic endoscopy
over ground. Surgical decision was based on history (sudden stop at maximal speed with signs attributable to an upper airway obstruction, including mouth breathing and expiratory fluttering noise) and resting endoscopy in 8 horses
(2 horses had persistent DDSP). All horses had resting endoscopic examination and no other upper airway disease
was identified.
R
bluntly separated and retracted (Inge Retractor, KMedic
,
R
R
Northvale, NJ). Suture (Fiberwire 5, Arthrex , Karlsfeld,
Germany) was threaded through both holes of a 3.5-mm Suture ButtonTM (Fig 1) and the ends drawn through the eye of
R
, Dreiea 48-mm half-circle trocar point needle (Acufirm
ich, Germany), which was passed through a single hole in
the thyroid cartilage. The needle was inserted ventromedial
to dorsolateral, 1 cm from the caudal border of the thyroid
cartilage, at the level of the sternothyroideus tendon insertion (Fig 2A). A NeedlePunchTM and a NeedlePunchTM
R
Suture Shuttle (Arthrex
, Karlsfeld, Germany) can also be
used for suture passage. Traction was applied to the suture
strands to pull the metallic button against the medial surface of the caudal aspect of the thyroid cartilage. Sternothyroideus tenectomy was performed. Surgery was performed
similarly on the right side.
Both ends of a 2-0 absorbable suture were drawn
through the eye of a blunt Deschamps needle for the use
as a threader. The needle was inserted rostral to caudal,
dorsal to the left side of the lingual process of the basihyoid
bone and the 2-0 suture strand used to pull the contralateral Fiberwire strand underneath (dorsal to) the basihyoid.
The geniohyoid muscle fibers were not dissected. The process was repeated on the right side. The 2 double suture
strands were tied in a single knot located on the midline
ventral to the basihyoid so that the rostral border of the
thyroid cartilage was ∼1.5 cm dorsal to the caudal border
of the basihyoid (1 index finger could be placed between
the 2 structures). The horse’s head was flexed temporarily
to facilitate suture tightening. When the thyroid wings were
not symmetric after the first throw, the first knot could
be easily loosened and tied again. The knot was secured
and a custom bent Suture ButtonTM (Landanger, Chaumont, France) was incorporated in subsequent throws on
the ventral surface of the lingual process of the basihyoid
bone (Figs 2B and C). This button was used to facilitate radiographic evaluation (Fig 2D). The surgical incision was
closed in layers.
Postoperative Care
Horses recovered from anesthesia without assistance. Procaine penicillin (22,000 U/kg, intramuscularly twice daily)
and phenylbutazone (4.4 mg/kg, intravenously once daily)
were administered for 7 days. Horses were hand-walked for
2 weeks until skin staple removal and then training resumed.
Radiographic Assessment
Lateral radiographs were taken 24 hours postoperatively
with head in a neutral position. Distance between caudal
and rostral metallic buttons was measured.
Surgical Procedure
Anesthetized horses were positioned in dorsal recumbency
with the head in full extension. A 15-cm median incision was
made between the basihyoid bone and the 1st tracheal ring.
The paired sternohyoideus and omohyoideus muscles were
2
Follow-up
Referring veterinarians were asked to take a follow-up
lateral radiograph after the horse resumed full training.
C Copyright 2012 by The American College of Veterinary Surgeons
Veterinary Surgery 00 (2012) 1–4 Rossignol et al.
Modified Laryngeal Tie-Forward Technique
Follow-up was obtained by telephone communication with
trainers or owners in July 2010 to determine if there were
any wound complications and residual airway noise, and to
determine current activity level of the horse.
RESULTS
Breed distribution of the 27 horses was 18 Standardbred
and 5 Thoroughbred racing horses, 3 jumping horses, and
1 leisure horse. There were 13 mares, 8 colts, and 6 geldings, between 3 and 10 years of age. Surgery was performed
without complication in all horses. Mean ± SD surgical
time was 30 ± 10 minutes.
On postoperative radiographic examination, the position of the 3 metallic implants was clearly visible with the
thyroid cartilage dorsal to the basihyoid bone (Fig 2D). The
median reduction distance was 3.25 cm [range, 1.6–5.4 cm].
Four horses (16%) developed surgical site seroma that
resolved with needle drainage. One horse had an infection
that required sutures and button removal.
Mean follow-up for 26 horses was 9 months (range, 2–
23 months). Nineteen horses were performing successfully
(17 race horses, 2 show-jumping horses); however, followup radiographs were not taken. Of the other 7 horses, 2
horses had been retired for unrelated reasons, 2 horses did
not return to their previous activity level, 2 were considered
failures (1 implant infection, 1 persistent DDSP initially
that still had DDSP at maximal speed), and 1 was in full
training without clinical signs. No difference was found between immediate postoperative and follow-up radiographic
measurements except in the implant infection for which
measurements were different and the caudal metallic buttons were not superimposed.
DISCUSSION
Figure 2 (A) Ventral view showing placement of first suture in the
left lamina of the thyroid cartilage before pulling the Suture ButtonTM
R
(Acufirm
, Dreieich, Germany) tight against the medial surface of the
lamina. Ventral view (B) and lateral (C) views showing positioning of
the custom metallic button on the ventral aspect of the basihyoid after
the left and right suture strands have been tied. (D) Lateral radiographic
view of the 3 suture buttons.
Compared to the technique described by Cheetham et al7 ,
we have the sutures exit symmetrically through a single port
from each lamina of the thyroid cartilage with a Suture
ButtonTM resting against the medial aspect of each thyroid
lamina. Each double strand is tied to achieve a single knot
incorporating a third metallic button positioned on the ventral aspect of the hyoid bone. In our experience, by using
equal tension on both double strands symmetrical positioning of the larynx can be achieved. Sutures were tied to
position the thyroid cartilage, 1.5 cm dorsal to the basihyoid
bone independent of the rostrocaudal position of the thyroid cartilage. We used this method of laryngeal placement
based on Cheetham’s study, where a more dorsal and less
rostral laryngeal position was associated with an increased
probability of racing postoperatively.7 Our technique
minimized dissection and bleeding compared with the original technique where the soft tissue attachment dorsal to the
basihyoid bone is separated over an area of ∼10 mm2 .3 We
C Copyright 2012 by The American College of Veterinary Surgeons
Veterinary Surgery 00 (2012) 1–4 3
Modified Laryngeal Tie-Forward Technique
Rossignol et al.
used a third, centrally located metallic implant as a marker
of knot position on lateral radiographs to facilitate pre- and
postoperative measurements.
The LTFP we report using 3 metallic implants facilitates radiographic evaluation of laryngeal positioning and
may increase suture resistance to pullout from the thyroid
cartilage. The technique also facilitated symmetric positioning of the thyroid cartilage cranially and dorsally.
ACKNOWLEDGMENTS
3. Cheetham J, Pigott JH, Hermanson JW, et al: Role of the
hypoglossal nerve in equine nasopharyngeal stability. J Appl
Physiol 2009;107:471–477
4. Barakzai SZ, Dixon PM: Conservative treatment for
thoroughbred race horses with intermittent dorsal
displacement of the soft palate. Vet Rec 2005;157:337–
340
5. Ducharme NG, Hackett RP, Woodie JB, et al: Investigation
of the role of the thyrohyoid muscles in the pathogenesis of
the dorsal displacement of the soft palate in horses. Equine
Vet J 2003;35:258–263
We thank Dr. N. Ducharme for his advice and Edouard de Rothschild Equine Foundation for his support.
6. Woodie JB, Ducharme NG, Kanter P, et al: Surgical
advancement of the larynx (laryngeal tie-forward) as a
treatment for dorsal displacement of the soft palate in
horses: a prospective study 2001–2004. Equine Vet J
2005;37:418–423
REFERENCES
7. Cheetham J, Pigott JH, Thorson LM, et al: Racing
performance following the laryngeal tie-forward procedure:
a case-controlled study. Equine Vet J 2008;40:501–507
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displacement of the soft palate in 92 horses during
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9. Robertz A, Ohnesorge B, Boening KJ: Laryngoplastik unter
verwendung metallischer implantate ein in-vitro-studie zur
haltekraft der kehlkopfknorpel. Pferdeheilkunde
2009;25:205–210
C Copyright 2012 by The American College of Veterinary Surgeons
Veterinary Surgery 00 (2012) 1–4