Consecutive Exotropia 1. General comments 2. Surgical audit

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Consecutive Exotropia 1. General comments2.
Surgical audit

• Lionel Kowal, Director
• Elaine Wong, 2005 Registrar 2006 Fellow
• OCULAR MOTILITY CLINIC
• CERA, RVEEH, MELBOURNE

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CONSECUTIVE XT

• Any XT happening after previous ET usually after
  ET surgery
• Rare spontaneous consecutive XT

Old medial rectus Surgery
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CONSECUTIVE XT - WHY?

• Ciancia CET. n390.
• 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 doesnt grow with the pt
• Speculative - no evidence

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The ET correction doesnt 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

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Core defect in consec XT

• Usually medial rectus underaction
• Rx Have to make MR function normal or near-
  normal for satisfactory long term result

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1 L XT A pattern LgtR MR UASO OA OU
Sup obl OA OU
L XT
XT greater on downgaze A pattern
MR UA L gt R
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2, RMR UA
R XT
RMR UA
Right Gaze LMR normal
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3, RMR UA
RMR UA
R XT
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4, LMR UA
LMR UA
L XT
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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

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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
• Speculative - no evidence

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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
• Average1.3
• Botox for consec ET 4 (10)
• Adjustables 19 (57 )

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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
• Adjustables often necessary 57
• Fat may be present
• NO surgical tables
• Guide Early ET 10 ?

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Pre-op Range 6 66 XT Av 31XTPost-op Range
18ET 45XT Av 02/32 ended up worse! - work in
progress
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22/32 10 ? 3/32 10 poor result
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Amblyopia no guide to surgical outcome
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Hyperopia no guide to surgical outcome
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Younger pts less likely to get bad results
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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 lt 35 ?
• Advance 1-2 MR if gt 35 ?
• 70 10? gt 50 one surgery.

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RESULTS 2

• Donaldson MJ, Forrest MP, Gole GA
• Surgical management of consec XT
• J AAPOS. 2004
• n59. 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 _at_ final follow-up LK 71
• 66 exodrift after surgery - mean 8 ?

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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 10? with V
• R 8.75, L 7.00
• R amblyopia 6/12
• No surgery

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Spontaneous consec XT

• 2
• 30 yo F
• Infantile ET ? Age onset XT
• RXT 35?
• R 7.50, L 4.50
• R 6/45
• R Rc/ Rs RET 7?

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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 dont want to touch surgically at
  an early age
• LK 70 pts with ET gt 6 2003-5
• 2/70 spontaneous consec XT

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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