Transcript Consecutive exotropia

Consecutive Exotropia
1. General comments
2. Surgical audit
Lionel Kowal, Director
Elaine Wong, 2005 Registrar & 2006 Fellow
OCULAR MOTILITY CLINIC
& CERA, RVEEH, MELBOURNE
CONSECUTIVE XT
 Any
XT happening after previous ET
[usually after ET surgery]
 Rare: spontaneous consecutive XT
Old medial rectus
Surgery
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
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
Core defect in consec XT
 Usually
medial rectus underaction
 Rx: Have to make MR function normal [or
near- normal] for satisfactory long term
result
#1 : L XT ‘A’ pattern L>R MR UA
SO OA OU
L XT
Sup obl
OA OU
XT greater
on downgaze
‘A’ pattern
MR UA
L>R
#2, RMR UA
R XT
RMR UA
Right Gaze
LMR normal
#3, RMR UA
RMR UA
R XT
#4, LMR UA
LMR UA
L XT
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
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. 2000 & Trans Am
Ophthalmol Soc. 1999

Use non- absorbable sutures -  recurrence of
stretched scar
Reason #7: Scar migration* [Ludwig]
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
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Median: 1
Average:1.3
Botox for consec ET : 4 (10%)
Adjustables: 19 (57 %)
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 ∆
Pre and post op results
Exotropia ---->
80
70
60
50
<--- Esotropia
(Δ)
40
30
Pre op
Post op
20
10
0
0
5
10
15
20
25
30
-10
-20
-30
Patient number
Pre-op: Range 6 – 66 XT; Av 31XT
Post-op: Range 18ET – 45XT; Av 0
35
Post- op results
12
11
11
No. of patients
10
8
7
6
4
3
2
0
Excellent (0-5 ET/
XT)
Good (6-10 ET/ XT)
Imperfect (11-20
ET/ XT)
Poor (>20 ET/ XT)
Amblyopia and XT surgical results
60.00%
% of patients
50.00%
40.00%
No amblyopia
6/12 - 6/36
<6/48
30.00%
20.00%
10.00%
0.00%
No amblyopia
6/12 - 6/36
<6/48
Excellet
good
Imperfect
Poor
26.67%
36.36%
50.00%
40.00%
45.45%
0.00%
26.67%
9.09%
33.33%
6.67%
9.09%
16.67%
Hypermetropia and XT surgery results
70.00%
60.00%
% of patients
50.00%
40.00%
<+2.00
+2.00 - +4.00
> +4.00
30.00%
20.00%
10.00%
0.00%
<+2.00
+2.00 - +4.00
> +4.00
Excellent
Good
Imperfect
Poor
37.50%
20.00%
50.00%
25.00%
60.00%
33.33%
18.75%
20.00%
16.67%
18.75%
0.00%
0.00%
Age and XT surgery results
50.00%
45.00%
% of patients
40.00%
35.00%
<20
20-40
>40
30.00%
25.00%
20.00%
15.00%
10.00%
5.00%
0.00%
Excellent
Good
Imperfect
Poor
<20
44.44%
33.33%
22.22%
0.00%
20-40
33.33%
33.33%
20.00%
13.33%
>40
25.00%
37.50%
25.00%
12.50%
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.
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∆ : 71% @ final follow-up LK 71%
 66% : exodrift after surgery - mean 8 ∆
Spontaneous consecutive XT
2
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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
Spontaneous consec XT
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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
Spontaneous consec XT
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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 > +6 2003-5
 2/70 spontaneous consec XT
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