Secondary tethering of the spinal cord
after
primary
repair
of
the
spinal
lesion
in
children
with
myelodyplasia
is
a
well
known
risk
factor
for
further
neurologic
deterioration
primarily
affecting
the
lower
urinary
tract.
Thus,
early
diagnosis
of
the
re-tethered
cord
syndrome
is
important
to
minimize
irreversible
neurologic
damage.
The
aim
of
this
study
was
to
investigate
the
incidence
of
the
re-tethered
cord
syndrome
after
primary
repair
in
children
with
myelodysplasia
and
its
effect
on
the
bladder
and
sphincteric
function.
Another
aim
was
to
assess
the
role
of
urological
follow-up
in
the
early
diagnosis
of
the
re-tethered
cord
syndrome.
Methods:
Between the years 1995 and 1999, a total of 191 children
(average
age
28
months
with
a
range
of
1
month
to
12
years)
with
a
primarily
repaired
myelodysplastic
lesion
have
been
enrolled
into
this
study.
The
primary
spinal
lesion
was
myelomeningocele
in
113
(62%),
myelochisis
in
43
(26%),
tethered
cord
in
12
(8%)
and
dermoid
sinus
in
7
(4%).
All
children
were
followed
up
in
our
multidisciplinary
spina
bifida
clinic
including
a
pediatric
neurosurgeon,
pediatric
internist,
pediatric
neurologist
and
a
neuro-urologist.
Neuro-urological
evaluation
and
follow
up
of
children
consisted
of
urine
analysis
and
culture,
urodynamic
studies,
voiding
cysto-urethrogram
and
urinary
system
ultrasonography.
The
frequency
of
follow
up
has
been
arranged
according
to
the
risk
of
neuro-urological
deterioration
as
described
in
the
literature
[1].
During
follow-up,
children
who
showed
worsening
of
urodynamic
parameters
or
deterioration
in
urinary
tract
imaging
were
further
evaluated
for
re-tethering
of
the
spinal
cord
by
magnetic
resonance
imaging
(MRI)
and
tibial
somatosensory
evoked
potentials
(TSEP).
A
decrease
in
bladder
compliance
and/or
a
development
of
detrusor
hyperreflexia
and/or
detrusor
sphincter
dyssynergia
and/or
worsening
of
incontinence
was
defined
as
a
urodynamic
deterioration.
A
new
appearing
or
increasing
vesico-ureteral
reflux
was
defined
as
a
radiological
deterioration.
Results:
Deterioration of urodynamic and/or
radiological
parameters
was
observed
in
38
(20%)
of
191
children.
Further
evaluation
of
these
38
children
with
MRI
and
TSEP
revealed
a
re-tethered
spinal
cord
in
26
(14%)
children.
Additional 4 children in our study group who did not have any urodynamic
and/or
radiological
deterioration
during
follow
up
were
also
diagnosed
with
a
secondary
tethering
because
they
developed
a
peripheral
neurological
deterioration
in
the
lower
extremities
as
detected
by
routine
neurological
examination.
The
time
interval
between
primary
repair
and
diagnosis
of
re-tethering
in
a
total
of
30
children
(16%)
ranged
from
4
months
to
14
years
(average
59
months).
In
the
present
study
population,
the
accuracy,
sensitivity
and
specificity
rates
of
a
neuro-urological
deterioration
in
the
diagnosis
of
a
re-tethered
spinal
cord
were
found
to
be
88%,
87%
and
92%,
respectively.
Conclusion:
Our study has shown that after the
primary
repair
of
their
spinal
cord,
16%
of
children
with
myelodysplasia
are
under
the
risk
of
a
secondary
tethering
where
87%
of
these
are
diagnosed
by
a
neuro-urological
surveillance,
only.
These
findings
underline
the
extreme
importance
of
a
neuro-urological
follow
up
in
children
with
myelodysplasia
after
the
primary
spinal
surgery.
Since
a
secondary
tethering
may
occur
even
at
14
years
after
the
primary
closure,
the
long-term
follow-up
appears
to
be
necessary.
Reference:
1. Predictive value of urodynamic evaluation
in
newborns
with
myelodysplasia.
JAMA,
252:650-2,
1984.
