strategies for re-operations in consecutive / recurrent strabismus start off with humility : it is...

Strategies for re-operations Strategies for re-operations in consecutive / recurrent in consecutive / recurrent

strabismusstrabismus

Start off with humility : it is Start off with humility : it is much easier than having it much easier than having it

thrust on youthrust on you

Fusion LVPEI Hyderabad 2012Fusion LVPEI Hyderabad 2012

Lionel KowalLionel KowalMelbourne, AustraliaMelbourne, Australia

1. Strategies for 1. Strategies for residual / residual /

consecutive / consecutive / recurrent recurrent

EsodeviationsEsodeviations

Residual / Recurrent ET : Residual / Recurrent ET : WHY?WHY?

#1 Reason: #1 Reason: Underplussed Underplussed

or otherwise accommodative.or otherwise accommodative.

Simple office test: pilocarpine Simple office test: pilocarpine 2% stat OU2% stat OU

Check cyclo refraction againCheck cyclo refraction again

Check cyclo refraction againCheck cyclo refraction again

Kowal Hyderabad 2012 Kowal Hyderabad 2012 33

Residual : WHY?Residual : WHY?Other less common Other less common

reasonsreasonsRange BMR for 15 – 50 Δ: surgical tables Range BMR for 15 – 50 Δ: surgical tables very reliable, but not 100% ‘bell curve’. very reliable, but not 100% ‘bell curve’.

R-R: has the LR slipped?R-R: has the LR slipped?

Is there an orbital problem : occult Graves’Is there an orbital problem : occult Graves’

Is there a supranuclear problem: ChiariIs there a supranuclear problem: Chiari

Is the globe unusually big: ‘simple’ myopia Is the globe unusually big: ‘simple’ myopia OR ‘myopic strabismus fixus’OR ‘myopic strabismus fixus’


Does the muscle Does the muscle always end up where always end up where

you plan to put it?you plan to put it?PAT in ET study in late 1980’s. All PAT in ET study in late 1980’s. All recessions were photographed with recessions were photographed with calipercaliper

25 % were under- / over- recessed by 25 % were under- / over- recessed by ≥ 1mm ≥ 1mm even though the surgeon knew even though the surgeon knew the photo was going to be reviewedthe photo was going to be reviewed

±1mm can have 5-10Δ effect / muscle±1mm can have 5-10Δ effect / muscle

Uncertainty of scar formation Uncertainty of scar formation


Recurrent ET Recurrent ET after after

recess/resectrecess/resectConsider slipped LR.Consider slipped LR.

LK : aBduction deficit not apparent LK : aBduction deficit not apparent for >12 mo for >12 mo

Re-presented like ‘acute 6Re-presented like ‘acute 6thth’ , ’ , presumably having suddenly presumably having suddenly exceeded motor fusional reserveexceeded motor fusional reserve

? Detect with 50 MHz UBM?? Detect with 50 MHz UBM?

Kraft successful; Kowal not reliableKraft successful; Kowal not reliableKowal Hyderabad 2012 Kowal Hyderabad 2012 66

Occult Graves’Occult Graves’Rare in childhood / Rare in childhood / adolescenceadolescence

Uncommon cause of poor Uncommon cause of poor surgical result in ET in surgical result in ET in adolescentsadolescents

ENLARGED MUSCLE STRABISMUSENLARGED MUSCLE STRABISMUS

Kowal et alii in ‘Progress in Strabismology’: 9th meeting of the Kowal et alii in ‘Progress in Strabismology’: 9th meeting of the International Strabismological Association’ 2003, @ pp 257-9International Strabismological Association’ 2003, @ pp 257-9


Residual : WHY?Residual : WHY?Range BMR for 15 – 50 Δ: surgical tables very Range BMR for 15 – 50 Δ: surgical tables very reliable. Expectation 2reliable. Expectation 2ndnd surgery ~10% in Y1 surgery ~10% in Y1



Is there a supranuclear Is there a supranuclear problem: Chiariproblem: ChiariIs the globe unusually big: ‘simple’ myopia OR Is the globe unusually big: ‘simple’ myopia OR ‘myopic strabismus fixus’‘myopic strabismus fixus’


Chiari: age at presentation of strabismusKowal L, Yahalom C, Shuey NH

Chiari 1 malformation presenting as strabismus BVQ 2006; 21:18-26

Most of the patients presented outside normal age range for strabismusKowal Hyderabad 2012 9

Residual : WHY?Residual : WHY?Range BMR for 15 – 50 Δ: surgical tables very Range BMR for 15 – 50 Δ: surgical tables very reliable. Expectation 2reliable. Expectation 2ndnd surgery ~10% in Y1 surgery ~10% in Y1



Is there a supranuclear problem: ChiariIs there a supranuclear problem: Chiari

Is the globe unusually big: Is the globe unusually big: ‘simple’ myopia OR ‘myopic ‘simple’ myopia OR ‘myopic strabismus fixus’strabismus fixus’


‘‘Simple myopia’ - Simple myopia’ - Modify surgical dose Modify surgical dose

for axial lengthfor axial lengthData is ? inconclusive / supportive - in the Data is ? inconclusive / supportive - in the eye of the readereye of the reader

Large globe = larger circumferenceLarge globe = larger circumference

Need larger recession to achieve same Need larger recession to achieve same angular effect as on a small globeangular effect as on a small globe

LK: normal globe 22mm ± 10%LK: normal globe 22mm ± 10%

>24.2 mm: augment recession dose by 10%>24.2 mm: augment recession dose by 10%

>26.4 mm: … by 20%>26.4 mm: … by 20%


ET of Myopic Strabismus Fixus – ET of Myopic Strabismus Fixus – have to do the correct operationhave to do the correct operation

Kowal Hyderabad 2012 Kowal Hyderabad 2012

Preoperative

181.1 deg.

LR

SR

Postoperative

103.6 deg.

LR

SR

. From Yokoyama1212

Some rare Some rare reasonsreasons

Sphenoid sinusitisSphenoid sinusitis

Ditropan medication for Ditropan medication for enuresisenuresis

Oxybutynin-associated esotropia Wong, Harding & Kowal J Oxybutynin-associated esotropia Wong, Harding & Kowal J AAPOS 2007;11:624-625AAPOS 2007;11:624-625. .


Treatment of Residual / Treatment of Residual / Recurrent ET: Recurrent ET:

What to do now?What to do now?

1. Push +1. Push +

2. MR Botox: 2. MR Botox:

very good for ~20 Δ very good for ~20 Δ residual ETresidual ET

3. Reoperate3. ReoperateKowal Hyderabad 2012 Kowal Hyderabad 2012 1414

Kowal Hyderabad 2012

Table 1 : Botox in EsotropiaSahare, 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

15

Principles of residual ET Principles of residual ET surgery surgery

ReoperationReoperation 11 If there’s a problem If there’s a problem [e.g. slipped LR] you [e.g. slipped LR] you must fix itmust fix it

Difficult / Difficult / unpredictable. Use unpredictable. Use adjustables.adjustables.



2. Previous BMR: 2. Previous BMR: FDT. If MR tight: plan to recess a little moreFDT. If MR tight: plan to recess a little more

Explore each MR. If MR already @ 11 - Explore each MR. If MR already @ 11 - 11.5mm from limbus, don’t recess more – 11.5mm from limbus, don’t recess more – will result in consecutive XT [whereas MR will result in consecutive XT [whereas MR Botox won’t] Botox won’t]

LR resect OU: deduct 0.5mm per muscle LR resect OU: deduct 0.5mm per muscle from usual tablesfrom usual tables

Difficult / unpredictable. Use adjustables. If Difficult / unpredictable. Use adjustables. If too young, improve the springback testtoo young, improve the springback test



3. After Recess – Resect3. After Recess – ResectFDT. If MR tight: plan to recess a little FDT. If MR tight: plan to recess a little moremore

Explore each MR. If MR already @ 11 - Explore each MR. If MR already @ 11 - 11.5mm from limbus, don’t recess more – 11.5mm from limbus, don’t recess more – will result in consecutive XT [whereas will result in consecutive XT [whereas Botox won’t] Botox won’t]

R-R other eye is usually the most R-R other eye is usually the most predictable operationpredictable operation

Difficult / unpredictable. Use adjustables.Difficult / unpredictable. Use adjustables.


Re-recessing the MR – Re-recessing the MR – guidelines to get me guidelines to get me

startedstartedLet us say I have a pt with residual or Let us say I have a pt with residual or recurrent ET of 25Δ. recurrent ET of 25Δ.

On a normal globe, it is safe to recess On a normal globe, it is safe to recess to 6.5mm from limbusto 6.5mm from limbus

If I want an extras 25Δ effect = 12.5Δ If I want an extras 25Δ effect = 12.5Δ from each of 2 muscles.from each of 2 muscles.


Re-recessing the MR Re-recessing the MR – guidelines to get – guidelines to get

me started me started

Let us say I find the MR Let us say I find the MR 8.5mm from limbus = 8.5mm from limbus = 3mm recess = ‘A’ 3mm recess = ‘A’

BMR 3 is for ET 15Δ. BMR BMR 3 is for ET 15Δ. BMR 5.5 is for ET 40Δ. 5.5 is for ET 40Δ.

The difference is 40 -15 = The difference is 40 -15 = 25Δ = 12.5Δ x 2. 25Δ = 12.5Δ x 2.

Each MR if moved from Each MR if moved from 3mm recess to 5.5 mm 3mm recess to 5.5 mm recess can be expected to recess can be expected to have a 12.5Δ effect.have a 12.5Δ effect.

So I can expect that when So I can expect that when I move an MR from ‘A’ a I move an MR from ‘A’ a distance of 2.5mm and a distance of 2.5mm and a 22ndnd muscle for a 12.5Δ muscle for a 12.5Δ effect I will get the 25Δ effect I will get the 25Δ effect I need effect I need Kowal Hyderabad 2012 Kowal Hyderabad 2012 2020

FROM KEN WRIGHT’S BOOK

Consecutive ETConsecutive ETSimple – not worrying:Simple – not worrying:

Small angle, intermittent, week 1 after 1st XT Small angle, intermittent, week 1 after 1st XT surgery, not bothersome to patientsurgery, not bothersome to patient

Of Greater Concern:Of Greater Concern:

Larger angle [esp ≥20Δ] , ≥2 previous Larger angle [esp ≥20Δ] , ≥2 previous surgeries, some incomitance, bothersome to surgeries, some incomitance, bothersome to patientpatient

Of Very Great concern:Of Very Great concern:

≥≥25Δ in week 1 [esp. >30] , not improving 25Δ in week 1 [esp. >30] , not improving quicklyquickly


Valenzuela, A Valenzuela, A CLADE 2000 CLADE 2000

134 pts operated intermittent XT. Follow up >3y!134 pts operated intermittent XT. Follow up >3y!

If initial alignment between 5Δ XT & 20Δ If initial alignment between 5Δ XT & 20Δ ET: 90% ended up small phorias, E [≤5Δ] ET: 90% ended up small phorias, E [≤5Δ] or X [≤10Δ]or X [≤10Δ]

No difference in subgroups in this range [0-5Δ No difference in subgroups in this range [0-5Δ XT had same outcome as 15-20Δ ET]XT had same outcome as 15-20Δ ET]

≥≥15Δ XT: all had poor result15Δ XT: all had poor result

5 pts 25-30Δ ET: 3 ended up OK5 pts 25-30Δ ET: 3 ended up OK

Exodrift continued for ~12 moExodrift continued for ~12 mo


If not getting If not getting better…….better…….

LK preferred technique: MR LK preferred technique: MR botoxbotox

UK: ~ 50% success in delayed UK: ~ 50% success in delayed groupgroup

Repeat surgery - usually Repeat surgery - usually explore muscles and undo explore muscles and undo some of the surgerysome of the surgery


Kowal Hyderabad 2012

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

24

2. Strategies for 2. Strategies for consecutive / consecutive /

recurrent recurrent ExodeviationsExodeviations

HOW COMMON IS HOW COMMON IS CONSEC XT?CONSEC XT?

Alberto Ciancia Alberto Ciancia [Argentina][Argentina]: :

90% perfect early 90% perfect early alignment after cong ET alignment after cong ET surgery surgery [n=390][n=390]

30%30% consec XT over consec XT over next 25y next 25y [50% followup][50% followup]

2626Kowal Hyderabad 2012 Kowal Hyderabad 2012

50% of patients: 250% of patients: 2NDND & & 33RDRD decades after last decades after last

ET surgery ET surgery

MEDIAN TIME TO SURGERY 22 YRS. AVERAGE 23. 2727Kowal Hyderabad 2012 Kowal Hyderabad 2012

KOWALpersonal series

Scar remodeling after strabismus Scar remodeling after strabismus surgerysurgery

Irene Ludwig, MD, , MD, Alan Chow, MD , MD JAAPOS JAAPOS 4: 326-333; 20004: 326-333; 2000

““When we explored the … When we explored the … muscles of patients with such muscles of patients with such overcorrections, the overcorrections, the expectation was that the expectation was that the muscles would be found muscles would be found normally healed at their normally healed at their original surgical attachment original surgical attachment sites and that repositioning sites and that repositioning ….would repair the ….would repair the deviations. deviations.

… … many of the overcorrection many of the overcorrection cases demonstrated a cases demonstrated a segment of amorphous scar segment of amorphous scar tissue separating the tendon tissue separating the tendon from its attachment site on from its attachment site on the sclera”the sclera”


http://www.journals.elsevierhealth.com/periodicals/ympa/article/S1091-8531(00)40646-4/fulltext

http://www.journals.elsevierhealth.com/periodicals/ympa/article/S1091-8531(00)40646-4/fulltext

Scar remodeling after strabismus Scar remodeling after strabismus surgerysurgery

Relative to all reoperation cases, Relative to all reoperation cases, lengthened scars were estimated to be lengthened scars were estimated to be found … in the subset of patients with found … in the subset of patients with late overcorrections, in about 50%late overcorrections, in about 50% [LK [LK series: 42%]series: 42%]

Mean time between original strabismus Mean time between original strabismus surgery and scar repair 122 mo (range surgery and scar repair 122 mo (range 1-612 mo). 1-612 mo). [LK series: 307 mo][LK series: 307 mo]

Median age at time of repair 19 y (range Median age at time of repair 19 y (range 3-68 y) 3-68 y) [LK series: 33 y, range 3-68y !].[LK series: 33 y, range 3-68y !].


These are difficult These are difficult casescasesNeed to make MR function normal or Need to make MR function normal or

XT will recurXT will recur Difficult to dissect out tendons Difficult to dissect out tendons

Muscle ‘meat’ can be 20+ mm from limbusMuscle ‘meat’ can be 20+ mm from limbus

Try to use Mersilene or other non-absorbableTry to use Mersilene or other non-absorbable

Keep Mersilene knot >8-9mm from limbusKeep Mersilene knot >8-9mm from limbus

Adjustables often necessary Adjustables often necessary

Fat may be presentFat may be present

NO surgical tablesNO surgical tables

Intra-op ‘spring back’ as a guideIntra-op ‘spring back’ as a guide

Guide: Early ET ≥ 10 ∆Guide: Early ET ≥ 10 ∆ 3030

SUMMARY - SUMMARY - CONSEC XTCONSEC XT

Common in a dedicated Common in a dedicated strabismus practicestrabismus practice

Common in a cong ET populationCommon in a cong ET population

Expect 2/3 to do very wellExpect 2/3 to do very well

10% do not do well10% do not do well


Re-recessing the LR – Re-recessing the LR – guidelines to get me guidelines to get me

startedstartedLet us say I have a pt with residual or Let us say I have a pt with residual or recurrent XT of 25Δ. recurrent XT of 25Δ.

On a normal globe, it is reliable to On a normal globe, it is reliable to recess LR to 9mm from the original recess LR to 9mm from the original insertioninsertion

If I want an extra 25Δ effect = 12.5Δ If I want an extra 25Δ effect = 12.5Δ from each of 2 muscles.from each of 2 muscles.


Re-recessing the LR Re-recessing the LR – guidelines to get – guidelines to get

me startedme started

Let us say I find the LR Let us say I find the LR 4mm from insertion = ‘A’ 4mm from insertion = ‘A’

LR Rc 4mm OU is for XT LR Rc 4mm OU is for XT 15Δ. Rc 8 mm is for XT 15Δ. Rc 8 mm is for XT 40Δ. 40Δ.

The difference is 40 - 15 The difference is 40 - 15 = 25Δ = 12.5Δ x 2. = 25Δ = 12.5Δ x 2.

Each LR if moved from Each LR if moved from 4mm recess to 8 mm 4mm recess to 8 mm recess can be expected recess can be expected to have a 12.5Δ effect.to have a 12.5Δ effect.

So I can expect that So I can expect that when I move a LR from when I move a LR from ‘A’ a distance of 4mm and ‘A’ a distance of 4mm and a 2a 2ndnd muscle for a 12.5Δ muscle for a 12.5Δ effect I will get the 25Δ effect I will get the 25Δ effect I need effect I need Kowal Hyderabad 2012 Kowal Hyderabad 2012 3333

FROM KEN WRIGHT’S BOOK

Thank YouThank You

Yarra River footbridge Melbourne Australia3434Kowal Hyderabad 2012 Kowal Hyderabad 2012

strategies for re-operations in consecutive / recurrent strabismus start off with humility : it is...

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