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-OPERATION IS 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 → REDUCED MR 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-OPERATION IS 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-OPERATION IS 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:HISTORY TIME 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:HISTORY TIME 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 1 st 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 2 nd 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 2 nd opinions sensible for difficult cases Starting with humility is easier than having it thrust on you