====== Duane Syndrome ======

===== Description =====

  * Congenital abnormality of the 6th cranial nerve
    * 4th-8th week of gestation
    * Missing nucleus in most cases (4th week)
  * Abnormal innervation from 3rd cranial nerve

^Type^Abduction^Adduction^Deviation^Frequency^
|I|Poor|Normal|Ortho- or Esotropia|70%|
|II|Normal|Poor|Ortho- or Exotropia|15%|
|III|Poor|Poor|Ortho-, Eso- or Exotropia|15%|

===== Clinical Characteristics =====

  * Most sporadic, 5% autosomal dominant inheritance
  * More common in females than males.
  * OS affected more often than OD.
  * 80% of cases are unilateral, when bilateral it is usually asymmetric.
  * Gender and Laterality:

^Female^Male^OS^OD^OU^
|58%|42%|59%|23%|18%|

  * Gender and Laterality in 835 cases of Duane Syndrome. DeRespinis PA, Wagner RS, Guo S; Duane’s Retraction Syndrome. Surv Ophthalmol 38:257, 1993

===== Exam Findings =====
  * Narrowing of the palpebral fissure and retraction of the globe of the involved eye on attempted adduction.
  * The amount of limitation depends on the amount of co-contraction of the medial rectus and lateral rectus.
  * Abnormal firing of the lateral rectus is found with EMG testing.
  * Angle of deviation almost always less than 30D , usually less than 15D .
  * Face turn toward the side of limited movement- permits fusion.
  * Anisometropic Ambylopia 10-30%
  * Ipsilateral congenital hearing loss 5%

===== Selected Associated Syndromes =====

  * Most cases are isolated
  * **Goldenhar syndrome** (hemifacial microsomia, ocular dermoids, ear abnormalities, preauricular skin tags, eyelid colobomas)
  * **Wildervanck syndrome** (sensorineural hearing loss, Klippel-Feil anomaly- shortness of neck with fused or missing vertebrae)

===== Treatment =====

  * Treat Refractive Error
  * Consider treating Hyperopia > +2.50 if ET
  * Treat Amblyopia
  * Goals of Surgery:
    * Improve primary position alignment
    * Improve head turn
    * Decrease up-shoot or down-shoot
  * Surgical Treatment Possibilities
    * Eso-Duanes
      * Medial Rectus (MR) Recession
      * Bilateral Medial Rectus Recessions
      * Superior Rectus and/or Inferior Rectus transpositions
    * Exo-Duanes
      * Lateral Rectus (LR) Recession(s)
    * Up-shoots/Down-shoots
      * Recession with Y split or posterior fixation of LR

{{tag>strabismus syndrome}}