EPIGLOTTIC ENTRAPMENT:
CLINICAL OUTCOMES AND
RACE DAY PERFORMANCE
Daniel Shaw B.V.SC M.R.C.V.S Cert ap(E-SO)
Singapore Turf Club
NEW ZEALAND
Home of lord of the rings
EPIGLOTTIC ENTRAPMENTCLINICAL EVIDENCE IN PRACTICE
Sub epiglottic
tissue becomes
entrapped over
the epiglottis
Forces of Evil
First described 40
years agoBoles (1978) JAVMA
Without symptoms,
associated with
poor performance
PERFORMANCE
Shortened epiglottic length?
Tulleners (1990)
Predisposed to dorsal
dislocation of soft palate
Fulton (2012)
LARANGOTOMY
CURVED BIOUSTRY
HOOK
ENDOSCOPE GUIDED
INTRANASAL IN
STANDING HORSE
Honnas et al (1988)- Epiglottic entrapment a transnasal surgical approach to divide the
aryepiglottic fold in the axially in the standing horse- Vet Surgery
COMPLICATIONS- EVOLUTION TO
NEW METHODS
LACERATION OF SOFT
PALATE
ANAETHESIA INTRA
ORAL
Holcombe et al (1994)
Surgical repair of iatrogenic
soft palate defects in 2
horses JAVMA
ROSS et al (1993) Trans oral
axial division under
endoscopic guidance
JAVMA
Minimal
complications,
superior race
performance to
laryngotomy.
Lumsden(1994) Surgical
treatment for epiglottic
entrapment in horses 51
cases JAVMA
RISK OF GENERAL ANESTHESIA
Laser in standing
horse
Tulleners(1990) JAVMA
Safety hook
Intra oral in standing
horse
Lacourt (2009) How to use a
safety hook to treat EE in the
horse AAEP
Perkins et al(2007) 15 horse,
standing, intra oral,
endoscope guided
Vet Surgery
TO OPERATE OR IGNORE?
Operate in most cases,
variety of techniques
Don’t recommend surgery
• REF Brown et al EVJ (2005)
• Post racing survey 744 tb horses in
Victoria
• Detected EE in 7 horses
• Associated with superior athletic
performance
• “Surgical correction may not be
necessary”
𝑉𝑒𝑡 ≠ 𝐼𝑑𝑖𝑜𝑡
• ADVISE TO RUN HORSE
• ADVISE TO WITHDRAW HORSE
VET IS AN IDIOT!
DAIRY VS EQUINE SURGERY
MATAMATA NZ
HOBBITON
EVIDENCE BASED MEDICINE
STRONG EVIDENCE
IINTERVENTION STUDIES
Randomized prospective
controlled blind
CONTROLLED OBSERVATION
STUDIES
Cohort Study
Case Control Study
Cross Sectional Study
WEAK EVIDENCE
• CASE SERIES
• CASE STUDY
• OPINION
• EXPERIENCE
• MEMORY
BEARD AND WATSON VET CLIN EQUINE
(2007)REVIEW –EVIDENCE BASED EQUINE UPPER
RESPIRATORY SURGERY
Good EBM for EE is lacking-variety of reasons
Can review the literature-critical appraisal
Can perform clinical audit
Design a good observational study- prospective matched controls
MATERIAL AND METHODS
2008-2012 Epiglottic Entrapments and Singapore Turf Club.
Pulled from the records of Rx works
Able to determine race record post surgery web site
MATERIALS AND METHODS
Able to find a match control from the next MRA number up
that was racing at the time of surgery. Race records from the
website
Able to search Rx works for history of horse post op for any
complications .
Able to identify a group of horses that raced with the
epiglottis entrapment present, and compare race records
with same horses post surgery and matched controls. (Better
than pre and post surgery, and survey studies)
METHOD OF SURGERY- MACAU
RUSSEL AND WAINSCOT(2007) THE VET RECORD
• Injectable GA
• Simple equipment
• Knock down room only
• Horse on right side , person on left side
KEEP ENTRAPPING UNTIL NO LONGER SITS ON EPIGLOTTIS
HAND SIZE , SHARP TEETH. CUT IN TO THE TONGUE.
.
STATISTICS……..”MAGIC”
• Big
• Big
• Big
• Big
• Mistake.
• Strongly encourage to learn and do
• Excellent on line masters refreshers courses.
CASE SERIES 32 CASES OVER 5 YEARS
• INCIDENCE OF 0.6%
• PREVALENCE 7 cases 750 horses in Victoria (0.9 %)
“NOT uncommon in equine racetrack practice”
CASE SERIES
Minor Complication
“Normal Finding”
ACVS 2014
Sub epiglottic Tissue
Thickened adhered tissue
Chronic cases
Improved with time,
conservative treatment
Raced normally
Re entrapped, 2nd
surgery
More common with
Laryngotomy techniques
Raced normally between and
after surgeries.
Acute or months-years
COMPLICATION RATE –CASE SERIES
• 1/32 (3%) – 2nd surgery
• 2/32 –(6%) Incomplete clearance
• 3/32- (9%) “Excess granulation tissue”
• 18 % Total
• Reported rate 10% ACVS 2013 regardless of method
CASE SERIES
• Using this method is a safe, effective, comparative
complication rates with other methods.
• Problems with case series…bias, uncontrolled, not blind,
surgeon evaluating own work.
• Level of evidence –low
COHORT STUDY
• Matched controls
• Compared race records post surgery
• The exposure factor surgery to correct an epiglottic
entrapment, outcome race day performance
• Matched cohort of horses without epiglottic entrapment,
similar age, race experience, time in Singapore
COHORT STUDY
Total Races
WINS
PLACINGS
HORSES POST SURGERY
N=32
450
26
89
MATCHED CONTROLS
N=32
450
32
79
COHORT STUDY
winners
placers
losers
Post surgery 14
32
12
6
Matched
controls 32
8
9
15
COHORT STUDY
Chart Title
18
16
14
12
10
8
6
4
2
0
post surgery
controls
av starts
wins
placings
COHORT STUDY
Chart Title
30
25
20
15
10
5
0
post surgery
controls
av starts
wins
placings
RESULTS STATISTICS
• CHI SQUARED TESTS ON TOTAL RUNS, WINS ,PLACINGS
• CHI SQUARED TESTS ON WINNERS, PLACERS, LOSERS.
• WILCOXON SIGNED RANK TEST FOR NUMBER STARTS,WINS,PLACINGS POST
SURGERY DATE (MATCHED CONTROLS NON NORMAL DISTRIBUTION)
COHORT STUDY- CONCLUSIONS
• UNABLE TO REJECT THE NULL HYPOTHESIS (p>0.05)
• “NO SIGNIFICANT DIFFERENCE BETWEEN THE CASES
AND MATCHED CONTROLS”
• (INCORRECT STATEMENT…. Can either Reject the null hypotheses. Find a
significant difference (p<0.05) , or not reject.
•
……Cannot say the 2 groups are “the same”
•
Type 2 error versus type 1 error)
2ND COHORT STUDY- HORSES RACED WITH
EPIGLOTTIC ENTRAPMENT PRESENT.
• RX works, diagnosed pre race
• Stewards report-Post race examinations
• 19 Horses raced 20 times with an epiglottic
entrapment present.
• Had surgery and raced 289 times post surgery
2ND COHORT STUDY
N=19
First 3 finish (%)
Last 3 finish (%)
Horses with EE
5
65
Horses post EE correction
29
34
Matched controls
24
38
FINISHING POSITION- EE PRESENT,
CORRECTED, MATCHED CONTROLS
8
7
6
5
4
3
2
1
0
1st 3
last 3
EE present
EE corrected
matched controls
2ND COHORT STUDY –RESULTS
There is a significantly lower
chance of the horses running
in the first 3 (p=0.05)
There is a significantly great
chance of the horses running
in last 3 (p=0.03)
2ND COHORT STUDY –RESULTS
• Individually , some horses can perform well with
epiglottic entrapment(1 winner)
• Overall, horses will run first 3 less often and last 3
more often, if running with EE
• Evidence moderate
• Selection bias, numbers.
CONCLUSIONS………THE END!
• Attempted to apply EBM to a clinical problem in practice
• Intra oral EE axial cutting using curved hook under GA is a safe and effective
method of correcting EE
• Post surgery, horses can be expected to go on and have normal race
careers.
• Some horses can race well with EE present, but overall performance will be
significantly improved by surgical correction.