Transcript Fusion - re-operations - The Private Eye Clinic

Strategies for re-operations in
consecutive / recurrent strabismus
Start off with humility : it is much
easier than having it thrust on you
Fusion LVPEI Hyderabad 2012
Lionel Kowal
Melbourne, Australia
1. Strategies for residual /
consecutive / recurrent
Esodeviations
Residual / Recurrent ET : WHY?
#1 Reason: Underplussed
or otherwise accommodative.
Simple office test: pilocarpine 2% stat OU
Check cyclo refraction again
Check cyclo refraction again
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Residual : WHY?
Other less common reasons
Range BMR for 15 – 50 Δ: surgical tables very reliable,
but not 100% ‘bell curve’.
R-R: has the LR slipped?
Is there an orbital problem : occult Graves’
Is there a supranuclear problem: Chiari
Is the globe unusually big: ‘simple’ myopia OR
‘myopic strabismus fixus’
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Does the muscle always end
up where you plan to put it?
PAT in ET study in late 1980’s. All recessions
were photographed with caliper
25 % were under- / over- recessed by ≥ 1mm
even though the surgeon knew the photo was
going to be reviewed
±1mm can have 5-10Δ effect / muscle
Uncertainty of scar formation
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Recurrent ET after
recess/resect
Consider slipped LR.
LK : aBduction deficit not apparent for >12 mo
Re-presented like ‘acute 6th’ , presumably
having suddenly exceeded motor fusional
reserve
? Detect with 50 MHz UBM?
Kraft successful; Kowal not reliable
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Occult Graves’
Rare in childhood / adolescence
Uncommon cause of poor surgical
result in ET in adolescents
ENLARGED MUSCLE STRABISMUS
Kowal et alii in ‘Progress in Strabismology’: 9th meeting of the
International Strabismological Association’ 2003, @ pp 257-9
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Residual : WHY?
Range BMR for 15 – 50 Δ: surgical tables very reliable. Expectation 2nd
surgery ~10% in Y1
R-R: has the LR slipped?
Is there an orbital problem : occult Graves’
Is there a supranuclear problem: Chiari
Is the globe unusually big: ‘simple’ myopia OR ‘myopic strabismus fixus’
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Chiari: age at presentation of strabismus
Kowal L, Yahalom C, Shuey NH
Chiari 1 malformation presenting as strabismus BVQ 2006; 21:18-26
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Most of the patients presented outside normal age range for strabismus
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Residual : WHY?
Range BMR for 15 – 50 Δ: surgical tables very reliable. Expectation 2nd
surgery ~10% in Y1
R-R: has the LR slipped?
Is there an orbital problem : occult Graves’
Is there a supranuclear problem: Chiari
Is the globe unusually big: ‘simple’
myopia OR ‘myopic strabismus fixus’
Kowal Hyderabad
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‘Simple myopia’ - Modify
surgical dose for axial length
Data is ? inconclusive / supportive - in the eye of the reader
Large globe = larger circumference
Need larger recession to achieve same angular effect
as on a small globe
LK: normal globe 22mm ± 10%
>24.2 mm: augment recession dose by 10%
>26.4 mm: … by 20%
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ET of Myopic Strabismus Fixus – have to do
the correct operation
181.1 deg.
SR
SR
103.6 deg.
LR
LR
Preoperative
. Kowal
Hyderabad
2012
From Yokoyama
Postoperative
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Some rare reasons
Sphenoid sinusitis
Ditropan medication for enuresis
Oxybutynin-associated esotropia Wong, Harding & Kowal J AAPOS 2007;11:624-625.
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Treatment of Residual / Recurrent ET:
What to do now?
1. Push +
2. MR Botox:
very good for ~20 Δ residual ET
3. Reoperate
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Table 1 : Botox in Esotropia
Sahare, Kowal, Marshman

N
PRE INJ
POST INJ
%CHANGE


Residual
7
26 ∆
5 ∆
59

Consec
6
32
9
74

Large
5
64
22
66

Cong
1
80
0
100
with surgery
Kowal
Hyderabad 2012
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Principles of residual ET surgery
Reoperation
1
If there’s a problem
[e.g. slipped LR] you
must fix it
Difficult / unpredictable.
Use adjustables.
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Principles of residual ET surgery
2. Previous BMR:
FDT. If MR tight: plan to recess a little more
Explore each MR. If MR already @ 11 - 11.5mm from
limbus, don’t recess more – will result in consecutive
XT [whereas MR Botox won’t]
LR resect OU: deduct 0.5mm per muscle from usual
tables
Difficult / unpredictable. Use adjustables. If too
young, improve the springback test
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Principles of residual ET surgery
3. After Recess – Resect
FDT. If MR tight: plan to recess a little more
Explore each MR. If MR already @ 11 - 11.5mm from
limbus, don’t recess more – will result in consecutive
XT [whereas Botox won’t]
R-R other eye is usually the most predictable
operation
Difficult / unpredictable. Use adjustables.
Kowal Hyderabad
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Re-recessing the MR –
guidelines to get me started
Let us say I have a pt with residual or recurrent ET of
25Δ.
On a normal globe, it is safe to recess to 6.5mm from
limbus
If I want an extras 25Δ effect = 12.5Δ from each of 2
muscles.
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Re-recessing the MR –
guidelines to get me started
Let us say I find the MR 8.5mm
from limbus = 3mm recess = ‘A’
BMR 3 is for ET 15Δ. BMR 5.5 is
for ET 40Δ.
The difference is 40 -15 = 25Δ =
12.5Δ x 2.
Each MR if moved from 3mm
recess to 5.5 mm recess can be
expected to have a 12.5Δ effect.
So I can expect that when I
move an MR from ‘A’ a distance
of 2.5mm and a 2nd muscle for a
12.5Δ effect I will get the 25Δ
effect I need
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FROM KEN WRIGHT’S BOOK
Consecutive ET
Simple – not worrying:
Small angle, intermittent, week 1 after 1st XT surgery, not
bothersome to patient
Of Greater Concern:
Larger angle [esp ≥20Δ] , ≥2 previous surgeries, some
incomitance, bothersome to patient
Of Very Great concern:
≥25Δ in week 1 [esp. >30] , not improving quickly
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Valenzuela, A
CLADE 2000
134 pts operated intermittent XT.
Follow up >3y!
If initial alignment between 5Δ XT & 20Δ ET: 90%
ended up small phorias, E [≤5Δ] or X [≤10Δ]
No difference in subgroups in this range [0-5Δ XT had
same outcome as 15-20Δ ET]
≥15Δ XT: all had poor result
5 pts 25-30Δ ET: 3 ended up OK
Exodrift continued for ~12 mo
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If not getting
better…….
LK preferred technique: MR botox
UK: ~ 50% success in delayed group
Repeat surgery - usually explore
muscles and undo some of the
surgery
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Table 1 : Esotropia

N
PRE INJ
POST INJ
%CHANGE


Residual
7
26 ∆
5 ∆
59

Consec
6
32
9
74

Large
5
64
22
66

Cong
1
80
0
100
with surgery
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2. Strategies for
consecutive / recurrent
Exodeviations
HOW COMMON IS CONSEC XT?
Alberto Ciancia [Argentina]:
90% perfect early alignment
after cong ET surgery [n=390]
 30% consec XT over next
25y [50% followup]
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50% of patients: 2ND & 3RD
decades after last ET surgery
KOWAL
personal series
MEDIAN
TIME TO SURGERY
22 YRS.
2012
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Kowal Hyderabad
AVERAGE 23.
Scar remodeling after strabismus surgery
Irene Ludwig, MD, Alan Chow, MD
“When we explored the … muscles
of patients with such
overcorrections, the expectation
was that the muscles would be
found normally healed at their
original surgical attachment sites
and that repositioning ….would
repair the deviations.
… many of the overcorrection cases
demonstrated a segment of
amorphous scar tissue separating
the tendon from its attachment
site on the sclera”
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JAAPOS 4: 326-333; 2000
Scar remodeling after strabismus surgery
Relative to all reoperation cases, lengthened scars
were estimated to be found … in the subset of
patients with late overcorrections, in about 50%
[LK series: 42%]
 Mean time between original strabismus surgery
and scar repair 122 mo (range 1-612 mo). [LK series:
307 mo]
 Median age at time of repair 19 y (range 3-68 y)
[LK series: 33 y, range 3-68y !].
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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
 Try to use Mersilene or other non-absorbable
 Keep Mersilene knot >8-9mm from limbus
 Adjustables often necessary
 Fat may be present
 NO surgical tables
 Intra-op ‘spring back’ as a guide
 Guide: Early ET ≥ 10 ∆
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SUMMARY - CONSEC XT
 Common in a dedicated strabismus practice
 Common in a cong ET population
 Expect 2/3 to do very well
 10% do not do well
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Re-recessing the LR –
guidelines to get me started
Let us say I have a pt with residual or recurrent XT of
25Δ.
On a normal globe, it is reliable to recess LR to 9mm
from the original insertion
If I want an extra 25Δ effect = 12.5Δ from each of 2
muscles.
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Re-recessing the LR –
guidelines to get me
started
Let us say I find the LR 4mm
from insertion = ‘A’
LR Rc 4mm OU is for XT 15Δ.
Rc 8 mm is for XT 40Δ.
The difference is 40 - 15 = 25Δ =
12.5Δ x 2.
Each LR if moved from 4mm
recess to 8 mm recess can be
expected to have a 12.5Δ
effect.
So I can expect that when I
move a LR from ‘A’ a distance
of 4mm and a 2nd muscle for a
12.5Δ effect I will get the 25Δ
effect I need
Kowal Hyderabad 2012
FROM KEN WRIGHT’S BOOK
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Thank You
Yarra River footbridge Melbourne Australia
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