Bilateral Duane’s syndrome OMC unit
Case presentation
Duane’s retraction syndrome Core problem – LR has double innervation 3rd nerve & 6th nerve MR & LR co-fire on aDduction - determines retraction Clinical presentation depends on: how aberrant is LR innervation [% of 3rd vs. % of 6th] How tight the MR / LR become
Usual pattern: “Type 1” restricted ABduction some ET some retraction ET retraction on ADduction Limitation of ABduction Face turn ABduction restricted LR innervation tight MR ‘chronic ET ADduction restricted tight LR
Clinical presentation depends on balance of abnormal innervation to LR LR innervation 3 N 6N 30% 70% ET – less Some retraction on ADduction LR innervation 3N 6N 70% 30% ET more More retraction on ADduction ABduction restricted LR innervation tight MR ‘chronic ET’ ADduction restricted tight LR
TREATMENT Traditional: ipsi MR recession. No long term follow up Strabismus specialists rarely do this iatrogenic “Type 3” Usual surgery: contralateral MR Rc, or transposition of SR & IR Up & downshoot ipsi LR Rc & split Severe retraction LR fixation to periosteum & SR - IR transposition