Duanes Retraction syndrome

Question 1

Features of Duanes

Answer 1

• Congenital (Case reports of acquired but rare)
• Limited abduction
• Limited adduction common though may not be present
• Retraction of the globe and narrowing of the palpebral fissure on adduction
• Protrusion of the globe and widening of the palpebral fissure on abduction
• Can be unilateral or bilateral

Question 2

Further features

Answer 2

Limited abduction
Narrowing palpebral fissures
BSV in pp
LR and MR affected restrictions in horizontal gaze and globe retraction

Question 3

What can you see in the side view in Duane’s

Answer 3

Often easiest to see Retraction & Protrusion from the side view

Question 4

Globe retraction

Answer 4

Possible features
- AHP – usually face turn to achieve BSV and can fuse, updrift or down drift on adduction, they learn to suppress double vision and often see them when decompensating, defective convergence, positive FDT (dependant on aetiology and duration)- more likely in longer fibrosis, unilateral – more common in females, bilateral - more common in males, often asymmetrical so look for subtle limitations in other eye

Question 5

Fibroses muscle

Answer 5

causes restriction
Fibrosis happens because muscle is inactive

Question 6

Epidemiology of duanes

Answer 6

Occurs in around 1-5% of strabismus
1 in 1,000 – 1 in 10,000 of population
May be unilateral or bilateral (10-24%)
80% cases are sporadic (Kirkham 1970)
Left eye (74%) and females (60%) more commonly affected (Mohan et al 2008)
Common in Saudi arabia and other Asian cultures

Question 7

Duanes IS…

Answer 7

MECHANICAL

Question 8

Theories of duanes

Answer 8

-Initially caused by a tight LR, described as an inelastic band
-Congenital anomalous of the LR, tight due to nuclear aplasia or birth truama
-Dual insertion – MR was rotated and inserted posteriorly, used to explain globe retraction

Question 9

Surgery

Answer 9

After surgical procedures in Duane’s patients found these theories to be unlikely

Question 10

Innervation theories

Answer 10

• Breinin (1956) measured electrical potentials generated by the muscles at various potentials
• No LR activity in attempted abduction but maximum LR generated in adduction, possible reason for co-contraction and globe retraction
• Strachan and Brown – paradoxical innervations observed using electromyography which revealed variable LR activity but MR consistent
• Occasionally synergistic innervation between MR and vertical recti/obliques
  Reduced saccadic velocities showed reduced

Question 11

Classifying Duanes

Answer 11

Type A-C
Type 1-3

Question 12

Duanes A-C Brown 1950

Answer 12

Classified based on Ocular Motility
Type A- Marked limitation of abduction and much less limitation of adduction
Type B- Limited abduction but normal adduction
Type C- Limited adduction which exceeds the limitation of abduction

Question 13

Duanes 1-3 Huber 1974

Answer 13

Type 1, with limitation of abduction only - most common
Type 2, with limitation of adduction only
Type 3, with limitation of both ab- and adduction.

Question 14

Type 4- Schliesser et al 2016:

Answer 14

• 19/179 (5%) Synergistic Divergence
• Exotropia in Primary position, AHP, Palpebral fissure changes
• Full to nearly full abduction with absent adduction, and simultaneous abduction when viewing unaffected side
• Cause? Requires further investigatioN

Question 15

MRI findings

Answer 15

Each type of DRS has different MRI findings (11 Patients)
Type 1 absence of VIth nerve, hypoplasia of SO muscle and aberrant innervation of LR by extra branch of IIIrd nerve
Type 2 dual innervation of LR from both the VIth and an aberrant IIIrd nerve branch and hypoplasia of SO muscle
Type 3 hypoplasia of IIIrd nerve, the MR, IR & IO muscles (one patient) (Xia et al 2014)

Question 16

Splitting of LR

Answer 16

*Splitting caused by incomplete fusion of the superior and inferior mesodermal complexes
*Speculation that upper part innervated normally by 6th nerve and lower part receives branch of inferior division 3rd nerve
*2/5 pts with DRS showed split LR
Okanobu et al (2009)

Question 17

Supra nuclear/ infranuclear defect

Answer 17

Findings at autopsy:
1) Absence of cell bodies of 6th nerve
2) Absence of nerve itself
– Supply to LR from inferior division 3rd nerve
– Fibrosis present where LR has poor innervation

Question 18

Association with other conditions

Answer 18

Marcus Gunn, Crocodile tears and unilateral abducting nystagmus
Combination of absence of nerve and absence of innervation - Mechanical Fibotic syndromes to Congenital Cranial Dysinnervation discorders (CCDD) of which Duane’s is the most common, followed by CFEOM

Question 19

Hereditary?

Answer 19

Reports of families and evidence of a genetic basis. Large cohorts of CCDD in some parts of the world e.g. Saudi Arabia. 25/110 affected in one extended family (Chung et al, 2000). Monozygotic twins – concordant (Dirani et al, 2006) and discordant (Smith and Cibis, 1996) for Duane’s reported

Question 20

Genetic basis

Answer 20

DURS1 – location Chr 8q13 (Vicent et al, 1994)
Multiple patients mapped to this gene. Complexity of cytogenetic causes.
DURS2 – CHN1 gene – Chr 2q31.1 (Miyake et al, 2008)
Autosomal Dominant- seen in all family members
MRI studies show absent/hypoplasia of 6th, small ON and small 3rd Nerve and hypoplasia SO muscle
3rd Nerve dysinnervation of the LR is secondary due to failue of innervation by the 6th nerve- Duanes Type 1 and 3 observed

Question 21

Reasons for reduction of globe on adduction

Answer 21

• Co-contraction MR and LR
• Inelasticity of LR
• Anomalous insertion MR
• SR and IR try to help to adduct

Question 22

Reasons for narrowing palpebral fissure

Answer 22

• Mechanical ptosis due to retraction of globe
• Decrease in electrical activity of levator

Question 23

Reasons for protrusion and widening palpebral fissures

Answer 23

• Inhibition MR
• Co-relaxation
• SO and IO trying to aid abduction
• Mechanical effect of lid

Question 24

Reasons for updrift or downdrift on adduction

Answer 24

• Retracted eye more in line with the obliques
• Co-contraction of SR and/or IR with the LR
• Slippage of the LR up or down (‘Bridle’ effect)

Question 25

Reasons for A V, X pattern

Answer 25

*Changes in innervation to LR on elevation or depression

Question 26

Acquired duanes causes

Answer 26

Tumour in wall of 4th ventricle
(case report)
Report of skull base meningioma

Question 27

Differential diagnosis of acquired Duanes

Answer 27

Trauma
Mechanical cause: e.g Thyroid eye disease; myositis; neoplasms
Neurogenic palsies
Congenital ET

Question 28

Investigation

presentation, history and AHP

Answer 28

Presentation- Often within the first year of life but can be later and occasionally will present in adulthood
History- Particularly of Family History and Inheritance Pattern
AHP- Face turn to affected side if abduction greatest deficit. To unaffected side if limitation of adduction greatest

Question 29

Further investigation

VA,CT, OMs

Answer 29

Visual Acuity- Good where BSV maintained, risk of amblyopia if manifest in pp
Cover Test- Often BSV in pp or with AHP, Esotropia if abduction most affected, Exotropia if adduction most affected
Ocular Movements- As described in features and classification note: Limitations and grade, Changes to palpebral fissure, Retraction / Protrusion, Upshoots / downshoots, Alphabet patterns

Question 30

Type A,B,C

Answer 30

Type B- mechanical features restriction of adduction
Type C- restriction of abduction
Type A- adduction greater than abduction

Question 31

Management of Duanes

Answer 31

Correct refractive error, treat amblyopia, observation, prisms, BT and surgery if Marked AHP
decompensating, unacceptable appearance of deviation or retraction, diplopia which is troublesome

Question 32

Innervation to LR is…

Answer 32

unknown surgery on muscles known to innverate normally

Question 33

Botox

Answer 33

Used to ascertain if likely to reduce AHP and or increase field of BSV to reduce symptoms.
As results of surgery can be unpredictable some patients choose to continue with maintenance BT (14%).
Some patients (53%) demonstrate a long term reduction in the deviation (Dawson et al 2010)

Question 34

Surgery based on

Answer 34

• Deviation – ET vs XT
• Size of AHP
• Severity of Globe retraction and overshoots
• Degree of limitations
• FDT
• Extent of Field of BSV as central as possible less use of AHP

Question 35

Surgery ET in pp

Answer 35

• MR recession of affected eye
• Large contralateral recession of unaffected eye (-2 or better) caution with large co-contraction
• Large deviation or bilateral duanes, bilateral MR recession
• With large globe retraction – LR recess
• Transposition of vertical recti muscles to LR, with or without augmentation sutures and adjustable (Britt et al 2004, Snir et al 2005)

Question 36

Surgery XT in pp

Answer 36

• Unilateral LR recession (XT common in type 3/2)
• Bilateral LR recession in large deviation
• Vertical recti transposition can also be performed
• Synergistic divergence – no definite surgical procedure

Question 37

Surgery globe retraction

Answer 37

Mild globe reaction, can be MR recess and resection of LR, if severe recess both MR and LR

Question 38

Surgery for over shoots

Answer 38

Y splitting of the LR with or without recessions (Rao et al, 2003)
Each half balances the other
IO myectomy with or without horizontal recti recess