EPIGLOTTIC ENTRAPMENT: CLINICAL OUTCOMES AND RACE DAY PERFORMANCEDaniel 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 ENTRAPMENT- CLINICAL EVIDENCE IN PRACTICE

Sub epiglottic tissue becomes entrapped over the epiglottis

First described 40 years ago-Boles (1978) JAVMA

Forces of EvilWithout symptoms, associated with poor performance

PERFORMANCE

Shortened epiglottic length?

Tulleners (1990)

Predisposed to dorsal dislocation of soft palate

Fulton (2012)

LARANGOTOMY CURVED BIOUSTRY HOOK

Honnas et al (1988)- Epiglottic entrapment a transnasal surgical approach to divide the aryepiglottic fold in the axially in the standing horse- Vet Surgery

ENDOSCOPE GUIDED INTRANASAL IN STANDING HORSE

COMPLICATIONS- EVOLUTION TO NEW METHODS

LACERATION OF SOFT PALATEHolcombe et al (1994) Surgical repair of iatrogenic soft palate defects in 2 horses JAVMA

ANAETHESIA INTRA ORAL

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 horseTulleners(1990) JAVMA

Safety hookLacourt (2009) How to use a safety hook to treat EE in the horse AAEP

Intra oral in standing horsePerkins 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

Horse runs poorly

• ADVISE TO WITHDRAW HORSE

• Horse runs well

VET IS AN IDIOT!

DAIRY VS EQUINE SURGERY

MATAMATA NZ HOBBITON

EVIDENCE BASED MEDICINE

STRONG EVIDENCE WEAK EVIDENCE

• CASE SERIES

• CASE STUDY

• OPINION

• EXPERIENCE

• MEMORY

IINTERVENTION STUDIESRandomized prospective controlled blind

CONTROLLED OBSERVATION STUDIESCohort StudyCase Control StudyCross Sectional Study

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 websiteAble 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- MACAURUSSEL 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 TissueThickened adhered tissue

Chronic cases

Improved with time, conservative treatment

Raced normally

Re entrapped, 2nd surgeryMore 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 SURGERYN=32

450 26 89

MATCHED CONTROLSN=32 450 32 79

COHORT STUDYwinners placers losers

Post surgery 32

14 12 6

Matched controls 32

15 8 9

COHORT STUDY

post surgery controls0

2

4

6

8

10

12

14

16

Chart Title

av starts wins placings

COHORT STUDY

post surgery controls0

2

4

6

8

10

12

14

16

Chart Title

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

1st 3 last 30

1

2

3

4

5

6

7

8

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.