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 Sup obl OA OU L XT 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] *Speculative - no evidence
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 %)
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-op: Range 6 – 66 XT; Av 31XT Post-op: Range 18ET – 45XT; Av 0 2/32: ended up worse! - work in progress
22/32 ≤ ± 10 ∆ 3/32 10% poor result
Amblyopia no guide to surgical outcome
Hyperopia no guide to surgical outcome
Younger pts less likely to get bad results
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 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 # 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 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