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Case of the week 156 (
January 2014 )
Traumatic 6th nerve palsy
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This 8 years old boy
suffered severe head trauma one year ago in an
auto accident. His eyes have been crossed since
the accident. He has diplopia but the images but
he is not particularly bothered. He feels better
when he turns his head to the left.
Vision: OD 20/20, OS 20/20
Refraction: OD + 0.50
OS + 0.50 +0.75 x 80 degrees
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See video of this patient |
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Traumatic 6th nerve palsy
Following sever head trauma,
the diagnosis of
Traumatic 6th Nerve Palsy
should not present any difficulties :
1.There is marked limited
abduction.
2.The
esotropia increases on attempts to abduct the
paretic eye.
3.
Most patients will complain
about double vision in lateral gaze and assume a
compensatory face turn in the direction of
the paralyzed muscle.
In traumatic
6th Nerve Palsy,
spontaneous recovery occurs in 84% of the unilateral and in 25% of the bilateral palsies.
Therapy
In determining whether a patient with traumatic
6th nerve palsy will require therapy
or not during the recovery period which last up to 6 months, the
extent to which the paralysis interferes with
comfortable single binocular vision must be
evaluated.
The eyes rarely move more than 1 5 degrees
from
the primary position. The diplopia occurs in lateral gaze is
tolerated by most patients. Like our patient here, with a paretic
left 6th nerve palsy, he may be
comfortable with his eyes in primary position and in
right gaze but he experiences diplopia only in
lt gaze. However, what is
tolerated by one patient may not be acceptable
to another.
In desperate situations in which single binocular
vision cannot possibly be restored by any means,
occlusion of one eye, preferably the sound eye, is a
last resort to create visual comfort for some patients.
Examination of the patient after 6 months of the
onset of head injury will reveal the extent to which
the lateral rectus muscle may recover ( partial or
full recovery ) , according to the finding data at
that time , the surgical plan - if needed - could be
done.
A maximal recession-resection
procedure suffices in incomplete
6th nerve paralysis. For a complete paralysis
I prefer to transpose the
temporal half
of each
vertical rectus muscle.
The Jensen muscle union
is less frequently performed now than only a few years
ago since it has been shown that this
procedure does not necessarily protect against
anterior segment ischemia .
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