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Diseases
of the Spine in Paediatrics
Copied from: http://www.health.adelaide.edu.au
Conditions of the spinal
column and intervertebral disc will not be discussed as they have
little neurosurgical involvement in children. Spinal trauma is
uncommon in paediatric practice and will not be discussed.
Conditions affecting the paediatric spine are unique. Most of the
conditions are congenital but they may persist until older age.
Often these conditions involve the spinal cord, spinal nerves as
well as the spinal column. I will discuss the common conditions
that are seen in Paediatric age group.
SYRINGOMYELIA
This is a condition where there is central cavitation of the spinal
cord. It starts by dilatation of the central canal, as the
dilatation progresses it extends into the parenchyma of the spinal
cord. At the end there is a very large central cavity filled with
clear fluid surrounded by a thin rim of spinal cord. Usually the
cavity wall is not smooth but septated. It is surprising that in
spite of the extent of the central cavitation and the thin rim of
the spinal cord tissue left very little clinical signs are seen.
Syringomyelia is classified as a primary and syringomyelia that is
secondary to other existing abnormalities. In children the
secondary syringomyelia is more common than the primary condition .
PRIMARY SYRINGOMYELIA
This condition is often seen with traumatic spinal cord injury. At
the site of injury there is a haematoma and liquefaction of the
spinal cord . There is scarring of the surrounding subarachnoid
space The subarachnoid scarring can produce pressure differential
above and below the scarring level causing the central cavitation.
As a result there is extension of the central cavitation rostrally
into the spinal cord.
It was
also suggested that viral ependymitis could cause scarring of the
central canal with entrapment of the spinal fluid creating
expansion of the central canal and central cavitation.
Central cavitation is commonly seen
with spinal cord tumours, this may be caused by the presence of a
high protein content of the cerebral spinal fluid and the expansion
of the spinal cord causing reduction in the subarachnoid space and
pressure differential.
Spinal
column abnormalities are often associated with syringomyelia as in
severe kyphosis and scoliosis. Small central cavities are also
seen with tethering of the spinal cord.
SECONDARY SYRINGOMYELIA
Syringomyelia
After post fossa decompression
Syringomyelia is associated with other abnormalities of the spinal
cord, the most common being Chiari Malformation.
Chiari Malformation is a condition where there is herniation of
the hindbrain into the upper cervical spine. This is classified
into
1 TYPE 1
Where there is herniation of the cerebellar tonsils into the
upper cervical canal.
2 TYPE 2
In this condition we have migration of the medulla oblongata and
4th ventricle into the upper cervical canal.
Chiari 2 malformation
3
TYPE 3
This is a rare condition where we have displacement of the entire
cerebellum and the 4th ventricle into the upper cervical
canal.
In Chiari 1 Malformation there is cerebellar tonsils herniation
into the upper cervical canal. The cerebellar tonsils ascend with
age. 6 mms hernia ion is regarded as normal in the first ten
years of life and 5 mms in the second ten years of life.
Chiari II Malformation is usually associated with myelomeningocele.
About 30% of patients with Chiari I Malformation have syringomyelia.
The aetiology of syringomyelia and Chiari 1 Malformation is
controversial. It was thought it is due to a small posterior fossa.
. Gardener suggested that the development of a syrinx is related
to the failure of normal outlets of the 4th ventricle.
Williams suggested that syringomyelia is due to pressure
differential between the intracranial cavity and the spinal cavity.
Chiari 1 Malformation presents with minimal symptoms. Examination
would reveal no or minimal neurological changes. Occasionally it
presents with respiratory signs. Scoliosis is commonly associated
with syringomyelia and Chiari 1 Malformation.
TREATMENT
In the presence of Chiari 1 Malformation .the management is to
decompress the posterior fossa, bony removal of the posterior margin
of the foramen magnum as well as C1 posterior arch. Some
Neurosurgeons recommends opening the dura and insertion of dural
graft, while others believe that simple decompression is enough.
In conditions where Chiari Malformation is not present cyst-
peritoneal shunt is done. If a spinal tumour is part of the
picture then removal of the tumour in most cases cure the
syringomyelia.
NEURAL TUBE DEFECTS
These conditions result from
disorder of closure of the neural tube and it involves the brain and
spinal cord. The neural tube starts as the neural plate, which
develops a groove in the middle called neural groove. It gradually
deepens until it is completely separated from the surface, that is
the ectoderm. This process is completed by the 28th day
of gestation. . The defect varies in severity from simple defect
in the posterior arch of the vertebra to complete failure of the
formation of the neural tube resulting in anencephaly.
SPINA BIFIDA OCCULTA
This is the simplest form
of neural tube defect; there is deficiency of the posterior arch of
the vertebra but no underlying neural abnormality. Usually the
skin overlying the defect is normal. The defect is usually
discovered incidentally after routine x-rays of the lumbar spine.
This defect is present in about 10% of the normal population and
does not cause any clinical problems and needs no treatment.
SPINA
BIFIDA APERTA
This represents an open
lesion where there is deficiency of neural covering or neural
elements are present on the surface of the skin.
1
Meningocele
In this condition we have a defect in the posterior vertebra arches
with protrusion of the neural covering to the surface of the skin.
The lesion appears as a cystic lesion covered with a thin
membrane. The lesion contains cerebro- spinal fluid but no neural
elements. Occasionally the lesion is covered with normal skin.
Clinical examination reveals no neurological deficits and x-ray of
the spine shows a defect in the posterior arches of the vertebral
column.
These cases are managed by excision of the sac and watertight
closure of the neural covering. This is followed by closure of the
overlying muscles and skin.
2
MYELOMENINGOCELE
In these cases there is herniation of neural elements to skin
surface. The lesion appears as a mass covered by thin and
occasionally transparent membrane, which is false dura, and within
the sac there is cerebro- spinal fluid and either part of the spinal
cord or spinal nerve roots.
CLINICAL PICTURE
This is a very complex condition where there is multiple systems
involvement.
A VERTEBRAL COLUMN
There are variable deformities of the spinal column. The posterior
vertebral elements are defective with widening of the spinal
canal. Other vertebral column anomalies are also seen in the form
of wedge vertebra and kyphosis and/or scoliosis. The defect in the
posterior column extends into several levels.
3
NEUROLOGICAL DEFICITS
This varies from complete loss of motor and sensory function from
the level of the lesion downward to partial loss of sensory and
motor power depending on the severity of the abnormality and the
amount of herniation of the neural elements into the defect.
Other associated neurological defects are common. In 90% of these
cases there is associated hydrocephalus and Chiari Malformation II.
4
SPHINCTERIC DISORDER
Invariably there is disorder of bladder and bowel function. In
severe cases there is a significant involvement of the kidneys and
the renal tracts.
5
LOWER LIMBS
The condition is often associated with talipes feet deformity.
The mobility of these children depends on the severity of lower limb
weakness. These patients need medical care for the rest of their
lives. They would need maintenance of renal and bowel function.
Care for spinal deformity and continuous care for associated
neurological problems as hydrocephalus and Chiari Malformation.
These children are usually managed by a Multi-disciplinary Team to
care for all their needs. The team would include a Neurosurgeon,
Orthopaedic Surgeon, Urologist, social workers, psychologists as
well as Physiotherapy, and Orthotic Specialists.
MANAGEMENT
Neurosurgical management involves repair of defective cover of the
lesion. The aim of is to re-institute the normal covering of the
spinal defect. The neural elements are replaced within the spinal
canal and then covered in a watertight manner by the neural
coverings. Over that some form of fibro muscular layer is
instituted and then skin closure. If the defect is large a Plastic
Surgeon is involved to create a suitable skin cover.
MYELOCELE
This is
the most severe form of spina bifida occulta. There is complete
failure of closure of the neural tube. On the surface of the skin
there is widely opened neural tube with a spinal cord exposed to the
surface. Usually there is no covering over the defect. This form
of defect is usually associated with complete loss of function below
the level of the lesion. This lesion is also associated with other
skeletal, urological as well as neurological abnormality as
mentioned above. The management is the same.
DIASTATOMYELIA
This is a
condition where we have the spinal cord is split in the middle into
two halves. Each half is surrounded by a separate dural sac. In
between the two halves there is a fissure, which usually contains a
bony spur or fibrous band, which arises from the back of the
vertebral body and attaches itself to the vertebral arch. This
condition is usually associated with other vertebral anomalies like
scoliosis, wedge vertebra and other bony anomalies. Occasionally
there is overlying cutaneous changes in the form of hairy patch or
skin pigmentation. Sometimes there is a dermal sinus overlying
that area. .
CLINICAL
PRESENTATION
As
mentioned above, cutaneous changes can be seen which would indicate
the presence of an underlying anomaly. Some cases would present
with limb and feet defects in the form of talipes deformity or
wasted leg. Other bladder and bowel changes can also be present.
Various motor or sensory changes are seen.
MANAGEMENT
The deformity should be
corrected; the bony spur would stop the normal ascent of the spinal
cord leading to traction and neural damage. Usually spinal cord
terminates at a lower level than normal.
The aim of management is to remove the bony spur to allow the free
movement of the spinal cord. The two dural sacs are opened and
changed into one dural sac containing both halves of the spinal
cord.
If early management is not instituted traction of the spinal cord by
the bony spur could cause further deterioration of neurological
function. This could be in the form of sphincteric disturbances
or further deterioration of motor and sensory function.
MYELOLIPOMA
This is a
congenital condition. The child is born with a soft lump in the
lumbar region, usually in the mid line and occasionally it extends
to one side of the lumbar area. Cutaneous changes are sometimes
seen in the form of a skin dimple. In most cases the child is born
with normal neurological status, occasionally changes in the lower
limbs are seen. This could be the form of hypoplastic leg or
talipes.
MORPHOLOGY
The
subcutaneous lipoma extends to a defect in the posterior arch of the
spinal column; it penetrates the dura and attaches itself to either
the dorsal surface or the caudal end of the spinal cord. Usually
the spinal cord is tethered at a low level. The fatty lump
infiltrates the parenchyma of the spinal cord. The dural defect
merges into the lipomatous tissue.
There are
two types of myelolipoma depending on its attachment to the spinal
cord. dorsal and caudal type.
MANAGEMENT
Ultrasound of the lumbar region delineates the lump and its
attachment to the spinal cord. It also shows the defect in the
posterior arches of the spinal column. MRI examination would give
more detailed information about the lipoma and the extent of
infiltration of the spinal cord.
It is the consensus of most Paediatric Neurosurgeon that the lesion
should be treated surgically at an early age. This is usually done
about 4 to 5 months of age. The aim of the operation is to
untether the spinal cord from the spinal lipoma. The spinal lipoma
is followed from the subcutaneous area into the spinal canal and it
its attachment is excised from to the spinal cord. Complete
removal of the spinal lipoma is not necessary. The aim is to
untether the spinal cord from its attachment to the lipoma. The
lipoma is excised away from the spinal nerve roots depending on its
attachment whether dorsal or caudal. Watertight closure of the
dura must be achieved.
It is well recognized that if the lipoma is not managed surgically
at an early age tethering of the spinal cord could later in life
lead to bladder and bowel problems as well as sensory and motor
changes in the lower limbs. Surgical treatment is undertaken at an
early age.
DERMAL SINUS
This is categorised into two
groupings.
The
sacrococcygeal dermal sinus.
This is usually is a small pit in the skin attached to the lower end
of the sacrum or the coccyx. This is an innocent lesion and does
not need any treatment. It is a superficial skin dimple, which
does not extend into the spinal canal.
LUMBAR
DERMAL SINUS.
These are more sinister
lesions and usually indicates the presence of lumbar spine
anomalies. The sinus extends into the spinal canal through a spina
bifida occulta and attaches itself to the dural sac. This could be
a portal for infection and can result in infection of the central
nervous system.
These lesions can also end in extra dural or intra dural dermoid
cysts. The presence of a dermal sinus also is a give away sign of
spinal anomalies as diastatomyelia or intra-dural cysts.
These
lesions should be fully investigated by MRI and treated surgically
if necessary.
TETHERED SPINAL CORD
The embryonic caudal eminence which is the part of the neural plaque
gives rise the distal conus and filum terminale as well as the
sacrum below S2 and portions of the lower genito-urinary system and
hindgut. Maldevelopment of this part can give to various
constellations of anomalies involving the conus, the filum terminale
as well as the lower genito-urinary system and hindgut.
Tethered spinal cord can be divided into three categories:
1
Tethering of the spinal cord associated with sacral ageneses and
lower genito-urinary system abnormalities as well as hindgut
abnormalities.
2
Tethered spinal cord associated with other spinal dystrophism as
myelolipoma.
3
Isolated spinal cord tethering.
In this chapter discussion is focused on isolated spinal cord
tethering.
SPINAL CORD
TETHERING
In this
condition we have low-lying spinal cord, the cauda equina terminates
below the normal level, which is L1-L2 vertebra. Many children
will have cutaneous marks.
CLINICAL PRESENTATION:
Children
not diagnosed early presents with back and leg pain, progressive
lower limb and spinal deformity and neurological deficits. Urinary
dysfunction and constipation is a common clinical presentation in
these children. Discrepancies in leg length, pescavus are also
seen. The symptoms usually start after the age of 2 years.
It is important that a tethered cord is diagnosed early, as the
outcome depends on early surgical treatment. Cutaneous
discolouration and skin dimples should alert Surgeons to the
possibility of spinal dysraphism and tethered cord.
MANAGEMENT:
MRI
study which would show the low-lying spinal cord. The filum often
contains small lipomas and is thicker than usual. The average
diameter of a normal filum terminale is about 2 mms.
The aim of surgery is to untether the spinal cord by cutting the
filum away from the cauda equina. In asymptomatic cases
surgical treatment prevents the development of deficits in the
future. In symptomatic cases surgical treatment would prevent
further deterioration, in a good percentage of cases there is good
recovery in neurological deficits. The earlier the treatment is
instituted the better is the outcome.
SPINAL TUMOURS
Spinal tumours are divided into:
1
Bony tumours of the spinal column.
2
Extra dural tumour.
3
Intra dural extra medullary.
4
Intra medullary tumours.
BONY TUMOURS OF THE
SPINAL COLUMNS
A
OSTEOID OSTEOMA AND OSTEO-BLASTOMA.
The osteoid osteoma presents with back pain localised over the
involved area, the pain is worsened by activity. Radiologically it
appears as a discrete lesion, which varies, from soft to sclerotic
bone. The osteoma can regress and spontaneous cure may occur.
Occasionally it would need surgical excision.
B ANEURYSMAL BONE CYST.
This
presents with pain and swelling over the lesion on radiological
examination it showed a collapsed vertebral body or vertebra plana.
Treatment consists of curettage of the lesion, which may need bone
grafting.
C EOSINOPHILIC GRANULOMA.
These granulomas are benign and can cause bone destruction. They
can be isolated or part of widespread disease like Hand -Schuller-Christian
Disease or Letterer-Siwe Disease. The lesion can cause collapse of
vertebra and present as a vertebra plana. Treatment is removal and
immobilisation. Bone graft may be necessary.
D EWING’S SARCOMA
These are tumours of long bones but the spine can be affected.
These are malignant tumours and can spread into the extra dural
space. Management is by biopsy, decompressive laminectomy,
radiotherapy and chemotherapy.
 
Ewing'sSarcoma
EXTRA DURAL TUMOURS
These
tumours are rare in children and usually is an extension of the bony
tumours into the spinal canal compressing the spinal cord.
INTRA-DURAL EXTRA MEDULLARY TUMOURS
These
are usually benign tumours and are rare in children. The most
common type of these tumours are meningiomas and schwannomas
the clinical presentation is spinal cord compression and involvement
of one or two spinal nerve roots. In most cases the tumour can be
excised completely achieving cure.
 
INTRA-MEDULLARY TUMOURS.
These
tumours account for about 5 –7% of central nervous system tumours in
children. They are relatively uncommon. Of the spinal cord
tumours, 40% are intra-medullary.
 
The types
of tumour that occur are either ependymoma or astrocytoma. These
could be of various degree of malignancy, however most of them are
low grade tumours.
 
myxopappilary ependymoma post op
CLINICAL PRESENTATION
Pain is
a very common clinical presentation before the development of
neurological signs. Later in the course of the disease other
motor or sensory changes can occur depending on the level of the
tumour.
A
separate entity of these tumours is the myxo papillary ependymoma,
which occurs in the lumbar region. It can involve only the filum
terminale or could extend into the conus medullaris. These tumours
can present suddenly as a result of haemorrhage in the tumour with
acute pain and significant neurological deficits.
MANAGEMENT
Surgical
exploration is indicated in the intra-medullary tumour for the
purpose of histological diagnosis and removal of the tumour of the
tumour. Ependymoma are more amenable to surgical excision than the
astrocytoma and separates more easily from the spinal cord
parenchyma.
In the
myxo papillary ependymoma of the cauda equina, complete excision is
possible with complete cure of the tumour is only involves the filum
and not the conus. Postoperative irradiation is indicated in the
intra-medullary tumour and in the paediatric population the response
is satisfactory.
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