Congenital malformations - Edocr

CHAPTER 4 SPINA BIFIDA 47
function, or tethering of the cord resulting from
scarring or failure of development of the conus
medullaris. In patients with low level lesions,
this can lead to local pain and progression of an
ascending motor deficit. Syringomyelia occurs
in many patients with spina bifida and may be
symptomatic, leading to upper limb, neck, or
shoulder weakness, often in association with
lower cranial nerve dysfunction. This may be
associated with progressive scoliosis above the
level of the spinal defect. Repeated neurosurgical
procedures may be necessary to address
some of these complications.
Patients with lower level lesions are more
likely to walk, and at an earlier age, than those
with higher level lesions, but some initial ambulators
eventually return to wheelchairs because
of problems posed by weight gain, cord tethering,
and other factors. Whether in braces or a
wheelchair, patients are always prone to pressure
sores because of lack of sensation. Similarly,
young children exploring their environment are
at risk of injury, particularly from burns.
A major problem for patients with
myelomeningocele relates to their lower urinary
tract dysfunction and rectal incontinence. In the
past, the natural history of the disorder was that
many patients developed end stage renal disease
by early adult life as a result of stasis and chronic
urinary tract infections. Standard therapy now involves
the use of clean intermittent catheterization
to manage the neurogenic bladder, which is
successful in many, but not all, patients. This may
be combined with oral anticholinergic agents. In
patients whose urinary incontinence is not successfully
managed medically, a variety of surgical
approaches have been described and are in use.
The rectal incontinence associated with spina bifida
is typically treated with a regimen of bowel
training using a routine of regularly scheduled
bowel emptying and is successful in most cases.
As many as 80% of patients with myelomeningocele
develop a latex allergy resulting from multiple
diagnostic and surgical exposures. 7 They
should be treated in a latex-free environment from
birth to avoid this complication.
A limited number of centers have developed
expertise with fetal surgery for surgical
closure of myelomeningocele in utero following
the prenatal diagnosis of this birth defect.
The impetus for intervention prenatally was
based on the hypothesis that there was progressive
damage to the exposed neural tissue,
supplemented by the observation that many
affected fetuses were noted to have leg movement
in utero, which was often no longer present
at the time of birth. Evidence accumulating
to date suggests that prenatal surgical closure
decreases the need for postnatal shunting for
hydrocephalus and may result in improved leg
function. 8,9 However, it clearly results in a significant
increase in obstetrical complications
including oligohydramnios, premature rupture
of the membranes, and preterm delivery. There
is no evidence of improved urinary tract function
and there are insufficient data to comment
on long-term intellectual outcome or motor
function.
Although survival statistics and the risk of
various complications varies considerably in different
series and may vary as a function of the
aggressiveness of postnatal management, some
generalizations can be reached and are useful
in counseling parents of a fetus or newborn diagnosed
with a myelomeningocele. Approximately
10–15% of infants with spina bifida are
stillborn. 10 Infants who are born alive without
associated anomalies have about an 87% chance
of living to be 1 year of age and a 75% chance
of surviving into adult life. 11 Eighty-five percent
will require shunting for hydrocephalus, 95%
will require at least one shunt revision, and over
30% will require surgery for a tethered cord release.
12 Close to 50% will develop scoliosis with
most of them requiring spinal fusion; one quarter
will have at least one seizure. More than 80%
will have bladder and bowel continence adequate
for socialization; 70% will have an IQ of
80 or above. 13 Late deterioration in motor and
renal function will be a common occurrence.
Lifelong comprehensive care by multiple specialists
will be a necessity.