STRABISMUS REOPERATION : A SECOND CHANCE

1. STRABISMUS REOPERATION : A SECOND CHANCE PRE-OPERATIVE EVALUATION LIONEL KOWAL MELBOURNE AUSTRALIA

2. STRABISMUS REOPERATION : A SECOND CHANCE Starting points: This will be difficult I need to be careful and accurate in my evaluation My pt’s expectations may be unrealistically high

3. STRABISMUS REOPERATION : A SECOND CHANCE PRE-OPERATIVE EVALUATION • How did the pt get to this point? • Full exam • Surgical plan • Patient’s expectations = Dr’s

4. THE NEED FOR RE-OPERATIONIS IT ANYONE’S FAULT? CONG ET NEED FOR RE-OPERATION CAN BE PART OF THE NATURAL HISTORY OF ALIGNMENT SURGERY

5. PART OF THE NATURAL HISTORY OF ALIGNMENT SURGERY CIANCIA’S EXTRAORDINARY PERSONAL SERIES OF CONG ET • BMR SOME: OTHER MUSCLES ALSO • WEEK 1: 90% ORTHOTROPIA • 5Y: 10% CONSEC XT • 15+Y: 30% CONSEC XT Follow up about 50%

6. NATURAL HISTORY OF SUCCESSFUL ALIGNMENT SURGERY IN CONG ET • THAT AMOUNT OF MEDIAL RECTUS REPOSITIONING REQUIRED FOR ALIGNMENT IN CONG ET WILL, WITH SUBSEQUENT GROWTH OF EYE, MUSCLE, ORBIT → REDUCEDMR FUNCTION IN 30% → XT NEEDING TREATMENT

7. NATURAL HISTORY OF SUCCESSFUL ALIGNMENT SURGERY IN CONG ET • SUCCESSFUL HORIZONTAL STRAIGHTENING DOES NOT PRECLUDE SUBSEQUENT DEVPT OF DVD REQUIRING Rx

8. THE NEED FOR RE-OPERATIONIS IT ANYONE’S FAULT? EXOTROPIAS • ET : MR ALWAYS TIGHT & MR Rc ADDRESSES THE BASIC PROBLEM. • XT DUE TO ‘ABNORMAL BALANCE OF FASCIAL FORCES WITHIN THE ORBITS’ • XT : LR NOT ALWAYS TIGHT. • LR SURGERY DOESN’T ALWAYS ADDRESS THE BASIC PROBLEM IN XT → HIGHER LONG TERM FAILURE RATE THAN ET

9. THE NEED FOR RE-OPERATIONIS IT ANYONE’S FAULT? SURGERY MECHANICALLY REALIGNS THE EYES EYES THEN HELD STRAIGHT BY: • STABLE MUSCLE- SCLERA UNION LUDWIG: NOT ALWAYS SO • NORMAL MUSCLE MECHANICS 5mm recess may function better than 7mm recess • FUSIONAL VERGENCE – KEEPS ANY MISALIGNMENT AS A PHORIA

10. SENSORY FACTORS IN MAINTAINING STRAIGHTNESS • GOOD SENSORY FUSION NEEDED FOR GOOD MOTOR FUSION • HIGH AMETROPIA esp high+→ POOR PERIPHERAL FUSION → SPONT / CONSEC XT MORE COMMON • POOR VISION → POOR PERIPH & POOR CENTRAL FUSION → SPONT XT MORE COMMON

11. PRE OPERATIVE EVALUATION:HISTORY REOPERATION FOR DIPLOPIA ACCURATE HISTORY : HOW TROUBLESOME IS IT? Diplopia itself Sore neck? COMMONLY MISSED BARRIERS TO FUSION: ** TORSION ** ANISEIKONIA

12. PREDISPOSITION TO DIPLOPIA REALIGNMENT IN PT WITHOUT DIPLOPIA: TESTS WITH probably GOOD Pos Pred Value FOR POST OP SINGLE VISION 1. CAN THE PT RECALL SINGLE VISION WHEN PERFECTLY ALIGNED? 2. PRISM & PAT 3. Botox testing [UK]

13. PRE OPERATIVE EVALUAION:HISTORYTIME COURSE OF STRAB Recurrence / overcorrection seen early has different etiology / Rx / expectations to that seen late Accurate history supported by Family Album Test important

14. PRE OPERATIVE EVALUAION:HISTORYTIME COURSE OF STRAB CASE 32 YO [XT], WORSE IF TIRED. ET & THICK GLS WHEN YOUNG RECALLS PARENTS’ / DOCTORS’ CONCERN ABOUT ADDUCTION IN Week 1 AFTER BMR age 7. NOW : LMR UA > RMR UA Manifest Refraction + 2 DS OU. Uncorrected vision 20/20.

15. PRE OPERATIVE EVALUATION HISTORY STRETCHED SCAR OF LUDWIG • POOR SCAR MATURATION / ILLNESS / MALNUTRITION INTERFERES WITH INTEGRITY OF MUSCLE/ SCLERA UNION → STRETCHED SCAR • LOOKS LIKE MUSCLE HAS SLIPPED WITHIN ITS TENDON • POTENTIALLY HAZARDOUS DURING SURGERY [‘SNAP!’]

16. PRE OPERATIVE EVALUATION HISTORY STRETCHED SCAR OF LUDWIG • ONE CAUSE OF CONSEC XT AFTER BMR • EXAMINE EASILY VISIBLE SURGICAL SCARS ON SKIN - ?THIN ATROPHIC SCARS MAY REFLECT MUSCLE / SCLERA UNION ? XS STRETCHMARKS • NON-ABSORBABLE SUTURES FOR REOP

17. PRE OPERATIVE EVALUATION:THE PLAN 40 yo WCF consec XT No baby photos – looked too bad 4 surgeries ages 2,8,12,13 variously ET /XT Never had diplopia ‘perfectly’ aligned ages 13-29 1st pregnancy @ 29: XT develops

18. PRE OPERATIVE EVALUATION:THE PLAN 40 yo WCF consec XT BCVA +3 etc 20/30+, +4 etc 20/40 XT 30Δ, XT’ 40Δ Smooth pursuit asymmetry RMR UA > LMR UA Scars all H recti

19. PRE OPERATIVE EVALUATION:THE PLAN 40 yo WCF consec XT EXPECTATIONS ? Over Rc MR OU ? Stretched scar SURGICAL PLAN Explore MR OU with great care Make MR function normal Early ET desirable = best result 2nd best result : larger early ET

20. PRE OPERATIVE EVALUATION: THE EXAMINATION • DO AN ACCURATE / COMPLETE STRAB EXAM • CHECK GLS FOR Δ & PALs • NEUTRALISE STRAB WITH Δ & CHECK SENSORY RESPONSE

21. PRE OPERATIVE EVALUATION:THE EXAMINATION : FACTORS THAT MAY MODIFY THE SURGICAL PLAN • IF LATERAL / VERTICAL INCOMITANCES LOOK FOR ALL THE USUAL ASSOCIATED FACTORS TO MAKE SURE IT ALL ‘FITS’

22. PRE OPERATIVE EVALUATION:THE EXAMINATION : FACTORS THAT MAY MODIFY THE SURGICAL PLAN • VERSION / DUCTION DEFICITS / OVERACTIONS • IS A DEFICIT DUE TO UA OR RESTRICTION? • MR UA looks like tight LR • FORCEPS TESTING – IS DUCTION DEFICIT DUE TO WEAKNESS OR RESTRICTION? • Rc LR when the MR is weak → result won’t last

23. PRE OPERATIVE EVALUATION:SPECIAL AND FANCY TESTS • RISK OF ISCHAEMIA NEED TO OPERATE ON ADJACENT MUSCLES • NORMAL IRIS ANGIOGRAM ENCOURAGING

24. PRE OPERATIVE EVALUATION:SPECIAL AND FANCY TESTS • WHEN TO SCAN • EVOLVING • IF THINGS DON’T ‘FIT’

25. PRE OPERATIVE EVALUATION • Reops are difficult for patient and Dr • Careful complete assessment • Careful pt education • 2nd opinions sensible for difficult cases • Starting with humility is easier than having it thrust on you