I Esotropic Duane
1. Esotropia with head straight
2. Face turn to involved side
3. Limited abduction
4. Near normal adduction
5. Mild (to severe) enophthalmos and fissure narrowing on adduction
6. Sensory status usually nomal
II Exotropic Duane
1. Face turn toward normal side
2. Limited adduction and no or minimal limitation of abduction
3. Marked upshoot and sometimes downshoot on adduction
4. Severe fissure narrowing on adduction with enophthalmos
5. May suppress or have normal sensory status
III Straight Duane
1. Limited abduction and adduction
2. Marked narrowing of the fissure on attempted adduction with enophthalmos
3. Upshoot and downshoot on adduction
4. Straight or nearly straight head position
5. Sensory status usually normal
IV Simultaneous Abduction
1. Large angle exotropia
2. Face turn to uninvolved side
3. Very limited adduction
4. Simultaneous abduction when looking toward uninvolved side
5. Usually suppresses
Treatment of Duane Syndrome
Each case of Duane syndrome requires a unique approach to treatment, if treatment is even considered.
The Goals of Treatment: (Reasons to treat Duane syndrome)
* Improved head posture
* Elimination or reduction of upshoot and downshoot in adduction
* Elimination or reduction of enophthalmos
* Alignment of eyes in primary position
The Limitations of Treatment: (Appropriate disclaimers)
* Normal ductions and versions cannot be achieved
* Upshoots, downshoots, and enophthalmos can be greatly reduced but not eliminated
* Fusing patient will continue to find areas of diplopia after treatment
* Complaints of diplopia with Duane tend to increase with the patient's age with or without treatment
Principles of Treatment for Duane Syndrome
The treatment of Duane syndrome is surgical. The surgery is aimed at reducing the unwanted effects of co-contraction of the medial and lateral rectus muscles. Successful surgery results in a straighter head position, a lessening of enophthalmos and upshoot and downshoot, and better alignment in primary position. Attempts at improving abduction are less effective and may even be harmful if the lateral rectus is overly tightened because this increases enophthalmos.
Timing of Surgery
The findings typical of Duane syndrome can be observed even in the very young, at a few months of age. Infants are often evaluated to rule out sixth nerve palsy from another cause or simply for esotropia. Surgery can be done at any time, but is usually deferred until the child is walking. Some reasons to consider surgical treatment early are concerns over motor development (walking, catching a ball, etc.), increased stiffness of the lateral rectus, and problems associated with the face turn (both appearance and posture).
Treatment Options for Duane Syndrome (Duane syndrome of the left eye is shown)
Recess medial rectus 3mm to 6mm (8.0mm to 11.5mm from limbus)
Posterior fixation suture to normal medial rectus
Can also recess M.R.
Do not resect L.R.
Vertical recti may be shifted fully to the corner of the lateral rectus of a few millimeters short
1. Recess medial rectus to center (align) the eye - this has no effect on abduction.
2. A posterior fixation suture on the normal medial rectus may diminish adduction innervation slightly in the involved eye making the esodeviation in the involved side less. Because the sixth nerve to the involved lateral rectus is absent, the "laudable secondary deviation" from Hering's law which would enhance innervation to the lateral rectus is not applicable in this situation.
3. Some surgeons have done full tendon transfer of the superior and inferior rectus to the lateral rectus. In all but the mildest cases this procedure may cause more harm than good, by either producing exotropia, increasing enophthalmos, or causing a new, iatrogenic, vertical deviation.
4. Never resect the involved lateral rectus. If done, this can turn a Type I into a severe Type II.