1. Consecutive Exotropia 1. General comments 2. Surgical audit
Lionel Kowal, Director
Elaine Wong, 2005 Registrar & 2006 Fellow
OCULAR MOTILITY CLINIC
& CERA, RVEEH, MELBOURNE

2. CONSECUTIVE XT
Any XT happening after previous ET [usually after ET surgery]
Rare: spontaneous consecutive XT
Old medial rectus
Surgery

3. CONSECUTIVE XT - WHY? Ciancia: CET. n=390.
perfect early alignment after Cong ET surgery  30% consec XT over next 25y
Reason #1:
If repositioned MR successfully aligns the eyes, subsequent growth of globe, muscle, orbit may alter this mechanical ‘balance’  mechanical disadvantage of repositioned MR *
The ET correction doesn’t ‘grow’ with the pt *
*Speculative - no evidence

4. The ET correction doesn’t ‘grow’ with the pt
Globe growth: ? Rc changes the way the sclera anterior to the new insertion subsequently grows : a 5mm Rc becomes a 7mm Rc *
*Speculative - no evidence

5. Core defect in consec XT
Usually medial rectus underaction
Rx: Have to make MR function normal [or near- normal] for satisfactory long term result

6. #1 : L XT ‘A’ pattern L>R MR UA SO OA OU
Sup obl
OA OU
L XT
XT greater
on downgaze
‘A’ pattern
MR UA
L > R

7. #2, RMR UA
R XT
RMR UA
Right Gaze
LMR normal

8. #3, RMR UA
RMR UA
R XT

9. #4, LMR UA
LMR UA
L XT

10. Early consec XT - WHY? More reasons
#2: Wrong surgical dose
Surgical tables assume normal globe size, average muscle stiffness [L-T curve], average scleral rigidity, average mechanical response of antagonist, ….
#3: Poor surgical technique
#4: Knots come undone
#5: Poor / aberrant early healing
Vicryl hydrolysis not uniform

11. Delayed consec XT - WHY? Reason #6
‘Stretched scar’ - look for stretchmarks, healing of other surgical scars, ….
Scar remodelling is an ongoing lifelong process
Scar is metabolically more active than tendon
Ludwig IH J AAPOS & Trans Am Ophthalmol Soc. 1999
Use non- absorbable sutures -  recurrence of stretched scar
Reason #7: Scar migration* [Ludwig]
*Speculative - no evidence

12. Audit of Consecutive XT
LK private pts, 2y to Oct 2005:
91 cases of consec XT
Av time to XT ~ 8 y
58/91 : XT surgery by LK
32 : follow up ≥1 y
Number of surgeries: 1- 4
Median: 1
Average:1.3
Botox for consec ET : 4 (10%)
Adjustables: 19 (57 %)

13. These are difficult cases
Need to make MR function normal or XT will recur
Difficult to dissect out tendons
Muscle ‘meat’ can be 20+ mm from limbus
Adjustables often necessary [57%]
Fat may be present
NO surgical tables
Guide: Early ET ≥ 10 ∆

14. Pre-op: Range 6 – 66 XT; Av 31XT Post-op: Range 18ET – 45XT; Av 0 2/32: ended up worse! - work in progress

15. 22/32 ≤ ± 10 ∆
3/32 10% poor result

16. Amblyopia no guide to surgical outcome

17. Hyperopia no guide to surgical outcome

18. Younger pts less likely to get bad results

19. RESULTS 1 Gomez De Liano Sanchez et al Consecutive exotropia surgery
Arch Soc Esp Oftalmol. 2001
Retrospective n= 30
Before surgery, 53% amblyopia, 67% rotation limitation.
LR Rc OU for < 35 ∆
Advance 1-2 MR if > 35 ∆
70%: ≤± 10∆ > 50% one surgery.

20. RESULTS 2 Donaldson MJ, Forrest MP, Gole GA
Surgical management of consec XT
J AAPOS. 2004
n=59. F/up ≥ 6w [mean 16 mo]
Sx : LR Rc, MR adv to original insertion
Time to XT Sx mean 14y (4mo-47 y) LK 8y
Mean preop XT 32 ∆ LK 31∆
Result ≤±10∆ : final follow-up LK 71%
66% : exodrift after surgery - mean 8 ∆

21. Spontaneous consecutive XT
2 cases of spontaneous consecutive XT
2% of all consecutive XT
High +, amblyopia, cong ET
# 1 : 10 yo F, infantile ET
XT first noted ~ 2 yo
Now XT 10Δ with V
R +8.75, L +7.00
R amblyopia 6/12
No surgery

22. Spontaneous consec XT # 2 30 yo F Infantile ET ? Age onset XT RXT 35Δ
R +7.50, L +4.50
R 6/45
R Rc/ Rs : RET 7Δ

23. Spontaneous consec XT Alan Scott : unpublished series n= 19
ET ≤ 20 ∆ Onset ≤ 2y
≥ + 4 DS Amblyopia ≥ 1 line
12/19 : spontaneous consec XT
Only 4/19 stayed ET
ET usually declined ≥ age 5
“This set you don’t want to touch surgically at an early age”
LK: 70 pts with ET >
2/70 spontaneous consec XT

24. SUMMARY - CONSEC XT Difficult
Common in a dedicated strabismus practice
Common in a cong ET population
Expect 70% to do very well
Expect 10% not to do very well