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” ≠ • 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.