Brown Syndrome
occur once in every 430 to 450 cases of strabismus.
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may be bilateral in approximately
10% of case
Brown syndrome is found in 10% to 24% of patients with vertical muscle paresis.
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Brown syndrome was described by Harold W. Brown
in 1949 as the superior oblique tendon
sheath syndrome.
MECHANISM
Shortening of the anterior sheath of the
superior oblique tendon. this theoryabandoned •
Restriction of the superior oblique tendon at the
trochlear pulley
congenitally inelastic or short tendon
Abnormal tendon-trochlear complex
Brown Syndrome
Restriction of the superior oblique tendon at
the trochlear pulley
FINDING
1. Deficient elevation in adduction
2. Less elevation deficiency in midline .
3. Minimal or no elevation deficiency in the
abducted position
4. Minimal or no SO overaction..
5. V pattern with divergence in upgaze
6. Restricted forced ductions •
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OTHER FINDINGS
1. Downshoot or hypotropia in adduction
2. Widening of the palpebral fissure on
adduction
3. Anomalous head posture
4. Hypotropia in the primary position
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DIFFERENTIAL DIAGNOSIS
1-I O PALSY
2-DOUBLE ELEVATOR PALSY
3- CONGENITAL FIBROSIS SYNDROM
4-BLOW OUT FX
5-THYROID OPHTHALMOPATY
5-ADHERENCE SYNDROM
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Brown syndrome
Congenital
Resolution of congenital Brown syndrome is
unusual but possible
Acquired form
Trauma in the region of the trochlea
Systemic inflammatory
Iatrogenic Brown syndrome
intermittent Brown syndrome, which may resolve
spontaneously.
Comparison of Inferior Oblique Muscle
Palsy With Brown Syndrome
Deficient elevation in adduction that improves in abduction but often not completely
Inferior Oblique Muscle Palsy Brown Syndrome
Forced ductions
Negative
Positive
Strabismus pattern
A pattern
V pattern
Superior oblique
muscle overaction
Usually present
None or minimal
In adduction, the palpebral fissure widens and a downshoot of the involved eye is often
seen; it can be distinguished from superior oblique muscle overaction because
downshoot in the latter condition occurs less abruptly as adduction is increased.
Brown syndrome OS
Divergence in upgaze
Down shoot in attempted elevation in adduction?
Down shoot in attempted elev. in adduct. (different than IO palsy)
Brown syndrome
mild
moderate
severe
hypotropia
in primary position
no
no
yes
downshoot of the
eye in adduction.
no
yes
yes
chin-up head posture and sometimes by
a face turn away from the affected eye in
sever cases
An unequivocally positive forced duction test
demonstrating restricted passive elevation
in adduction is essential for the diagnosis of
Brown syndrome.
Retropulsion of the globe
during this determination stretches the superior
oblique tendon and accentuates
the restriction.
When inferior rectus muscle fibrosis or inferior orbital blowout fracture
(the principal entities to be differentiated) produces a restrictive elevation deficiency,
the limitation to passive elevation is accentuated by forceps-induced proptosis of the
eye rather than by retropulsion.
Management
1.Observation :alone in about two thirds of all
Brown syndrome cases
2.rheumatoid arthritis or other systemic
inflammatory diseases
Systemic treatment
3.Corticosteroids injected near the trochlea
4.Sinusitis has also led to Brown syndrome
CT of the orbits and paranasal sinuses
Surgical treatment is indicated for the
most severe cases
Primary position hypotropia
Anomalous head posture
sheathectomy
has been abandoned in favor of ipsilateral superior oblique tenotomy
Iatrogenic superior oblique muscle palsy may
occur postoperatively. 44%-82%
Brown Syndrome
SO tenotomy
SR
IO
LR
LR
RM
IR
MR
SR
IO
IR
Superior oblique muscle palsy
Reduced:
By careful preservation of the intermuscular
septum during tenotomy.
This modification often produces an early
under correction that gradually improves
with time
Perform simultaneous ipsilateral inferior oblique
muscle weakening.
guarded tenotomy using an inert spacer sewn to
the cut ends of the superior oblique tendon
Controlling the gap between the cut ends with
an adjustable suture
These procedures eliminate the need for simultaneous inferior oblique muscle
weakening but sometimes result in a downgaze restriction due to adhesions to the nasal
border of the superior rectus muscle.
Care must be taken to avoid contact of the spacer to
nearby structures by preserving the intermuscular septum
Brown Syndrome
Chicken suture
In 1991, Wright described a superior oblique
expander procedure for browns syndrome and
superior oblique overaction with good results.
Originally, this procedure has been performed
with silicone band expander.
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Brown Syndrome
Silicone expander
Silicon Expander
Elongation with fascia lata
Elongation with Achill Tendon