Chapter IV. Spine
Spinal deformity and hypermobility of the head and neck in
cerebral palsy present us with complex and serious problems.
Hypertonicity of the cervical spine causes hyperextension and
excessive rotation of the neck such as neck postures in asymmetric
tonic neck reflex, inhibits turnover movement of the neck and trunk,
and decreases stability in head-up posture, in prone and sitting (Fig.
13A, 18A, 109AB). Involuntary extension and rotation of the
cervical spine in patients with athetosis result in degenerative
spondylosis and consequently cause disastrous radiculopathy or
radiculomyelopathy. Finally the patient could end up in a disastrous
total quadriplegic paralysis with total spinal cord injury, due to
compression of spinal cord (Fig. 108).
Scoliosis deformity of the thoracic and thoracolumbar region
is also disabling, causing pain in the back, presenting difficulty in
keeping upright posture on sitting and standing, decreasing turnover
and crawling activities with limited rotational movement, and
decreasing respiratory function.
For treatment of these difficulties, numerous procedures have
been proposed. However, because of difficulty in controlling
hypertonicity, enormous technical difficulties and postoperative
discomforts have been encountered and the results are not always
encouraging. Fusion of large number of the vertebral bodies are
needed in these procedures, since scoliosis deformity can be
corrected only by fusion of larger areas of thoracic, thoracolumbar,
and lumbar vertebrae. Fusion over a large area can severely disturb
rolling movements, resulting in difficulty in turnover. It can also
disturb rotational movements of the spine necessary in alternate
crawling and causes difficulty in sitting-up movements with the use
of trunk and hip rotation. Fusion between pelvis and lower lumbar
vertebrae also interferes with the activities of daily living. Even if
deformity is corrected, a lot of inconvenience can be caused to
patients due to decrease in independent activities. Hence treatment
which will preserve sufficient mobility and flexibility of the trunk for
these patients will be advisable. In such situations, introduction of
the concept of orthopaedic selective spasticity-control to the spine
provides us with effective correction and sufficient mobility, and the
results of its clinical application are highly encouraging.
The concept of OSSCS is beneficial, even in the treatment of
spinal problems, and all the problems related to excessive
hypertonicity in the trunk muscles can be effectively settled.
1. Cervical Spine
1. Extensor thrust posture
Functional anatomy
Antigravity muscles
Nonantigravity muscles
(See Chapter II, Head Control and Rolling over)
Combined activities of the antigravity muscles raise the head
and neck and keep them in upright posture. In prone position, the
extensors, such as the suboccipital muscles, interspinales,
intertransversarii, multifidus, semispinalis raise the head, and in
supine position, the flexors, such as longus colli, suprahyoid and
infrahyoid raise the head upright.
Historical reviews
Surgical control of abnormal position of the neck, such as
extensor thrust of the neck has not been mentioned in literature,
because of difficulty in defining the involved muscular factors.
Recently, electromyographic studies and motion analysis systems
were introduced to define the muscles responsible for causing
deformities in the lower extremities. However, it seems difficult to
define the hypertonic muscles of the cervical spine responsible for
causing deformity by the use of motion analysis system, since they
are not able to analyze which muscles are hypertonic and responsible
for deformed posture in general. For decision making which muscles
are more hypertonic causing head and neck deformity and
radiculopathy, and which muscles are more antigravity muscles,
electromyography and motor analysis system are of less use.
Selective dorsal rhizotomy is still not popular in the treatment
of cervical problems, because it would not be possible to identify the
nerves responsible for hypertonicity selectively, and so it would be
difficult to preserve antigravity muscles which keep the head upright.
So if selective dorsal rhizotomy is done for cervical spine,
antigravity muscles will be weakened with consequent loss of head
control and the head will become flail with loss of stability.
Manipulations for abnormal posture of the neck are injurious
to the vulnerable structures of cervical spine such as the
intervertebral discs and vertebral bodies causing spondylosis and
radiculomyelopathy in the future. Physiotherapy by means of
excessive stretching of the cervical spine should never be done.
Physiotherapy by itself to control abnormal posture of the neck has
its own limitations.
In such a situation, the OSSCS offers immense opportunity in
reducing this hazardous hypertonicity, in correcting abnormal
postures of the head and neck, in controlling abnormal postural
reflexes of the body, and in reducing radiculopathy and
radiculomyelopathy as a whole, while preventing spondylosis
changes in the cervical vertebrae and intervertebral discs (Fig. 13AB,
18AB, 29AB, 109AB, 111ABCD).
Surgical approaches
Considerations
(Fig. 13AB, 18AB, 29ABCDEF,124AB, 111ABCD)
ΚΚΚΚΚΚΚΚΚΚΚΚΚΚΚFig. 124: OSSCS for treatment of radiculopathy
ΚΚΚΚΚΚΚΚΚΚΚΚΚΚΚΚΚΚΚ due to excessive athetosis
47-year-old male, athetosis quadriplegia
124A: Before OSSCS
124B: After OSSCS
Surgical Technique
Orthopaedic Selective Spasticity-control Surgery
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[Caution: important]
The splenius capitis and cervicis are considered to be
important antigravity extensors of the head and neck to keep the
head upright. Here, to prevent weakness of these muscles and to
avoid consequent postoperative anterior tilt of the head and neck,
these muscles should never be released, especially when posterior
fusion, posterior fenestration and laminoplasty are combined. In
stead of these muscles, the longissimus capitis and longissimus
cervicis should be released.
Radiculopathy and radiculomyelopathy
Cervical spondylotic radiculopathy or radiculomyelopathy
complicating athetosis cerebral palsy is one of the disabling
problems observed in cervical spine. In 1962, Anderson and
associates reported cervical spondylosis with myelopathy in patients
associated with athetosis, described the progression of the symptoms
over several years in detail, and presented analysis of the causes.274
As Anderson and associates described that the irritating symptoms of
this disease are characterized by pain in the neck, shoulder girdle
and upper extremity, sensory loss and paralysis of the extremities,
disturbance in fine movements of the fingers due to stiffness, and
urinary and faecal incontinence.
One of the characteristics of this disease in cerebral palsy is
that spondylotic changes or prolapse of the discs are easily caused,
even in young patients due to repeated head movements from
childhood. Another serious aspect is that progression in the
symptoms is rapid and continuous, and patients will finally develop
total quadriplegia due to dysfunction of spinal cord (Fig. 108). A
disastrous condition with total paralysis, decubitus at sacral region
and urinary insufficiency can be finally induced.
Pathogenesis
Mechanism by which radiculopathy or radiculomyelopathy is
caused in cerebral palsy is controversial. Anderson and associates
made an analysis of the causes in the 9 patients with athetosis, and
stated that prolonged athetosis does not increase the incidence or
severity of cervical spondylosis, but once the changes were set in,
athetosis could aggravate myelopathy.274 Levine and associates
stated that prolonged duration and violence of the movement
disorder produced severe changes in the cervical spine, and
concluded that the dyskinesia was felt to be responsible for the
spondylosis resulting in neurological deficits.275 It is understandable
to say that compression of the nerve or spinal cord or subsequent
decrease in blood supply due to degenerated vertebral body or
intervertebral disc can be considered, as the main causative factors
for radiculopathy or radiculomyelopathy. It is also likely that
instability due to hypermobility of the neck and weakness of neck
muscle are other specific factors, causing minor edema or injuries to
the nerve and spinal cord. This can result in symptoms of sensory
loss or motor deficit.
Therefore, the most important and specific point in treating
radiculopathy or radiculomyelopathy is how to reduce this instability
and hypermobility in the neck. Mechanism which causes spondylotic
deformity in the vertebra and intervertebral disc can be a little d
ifferent from the one observed in non-athetosis human body, since
location of the spondylotic change complicating athetosis cerebral
palsy is mentioned to be different from that of non-athetosis patients.
Nishihara and associates reported in 1984 that the most
deformed bodies were those of C3, C4 and C5, and intervertebral
disc degeneration and spur formation were seen mostly at C3-4 and
C4-5.276 On the other hand, it is reported that the usual site of
cervical spondylotic myelopathy in non-athetosis patients is C5-6.
Nishihara suggested that this difference in the level of affection
between athetosis and non-athetosis could be attributed to the
difference in movement patterns of the cervical vertebrae.
Ebara and associates made analysis of the active motion in the
cervical spine in athetosis cerebral palsy through cineradiographic
motion analysis. Firstly, they commented that the gross
characteristic feature of cervical motion in athetosis cerebral palsy is
whip movement and suggested that some quick movement occur in
cerebral palsy patients. They further mentioned that both velocity
and acceleration during flexion-extension in cerebral palsy patients
were greater than the ones in normal subjects especially in the upper
cervical level. They also documented that the difference in velocity
between C4 and C5 compared to the one between the lower disc
levels in cerebral palsy was remarkable. They concluded that such
kinematic abnormalities were thought to generate a greater shearing
force and exert bending moment on the corresponding cervical
articulations, discs and facets, and also mentioned that listhetic
instability accompanied disc degeneration at the upper cervical
levels.277
Historical Reviews
Surgical treatment of radiculopathy and radiculomyelopathy
is still controversial. Laminoplasty including laminectomy is a
recommended procedure, based on the idea that this approach
reduces compression on the spinal cord. However, in many papers,
it has been reported that results were not as expected. In 1970,
Levine and associates reported a case of 38-year-old man, for whom
laminectomy was performed extending from T1 to C2. They
concluded that the result was very poor, with superimposed
abnormal movements and a rapidly progressing disability in a
four-year follow up.275
In 1982, McCluer reported all the 3 patients treated by
laminectomy had poor results. In laminoplasty, if solid fusion is not
obtained in the operated area, instability will remain and the result
would be discouraging.278 Instability will also be increased, due to
destruction of supporting structures such as antigravity muscles and
laminae by the surgery. It is true that there are many patients who
complained of increased pain, sensory irritability and decreased
motor ability after laminoplasty surgery. We have had an opportunity
to observe a laminoplasty conducted for a patient with myelopathy.
In this patient, OSSCS was initially conducted for treatment of
myelopathy, and improvements in symptoms were noted, with an
ability to walk with minimum support. However the patient desired
to have further improvements and so visited another university
hospital. There, laminoplasty was conducted. Soon after
laminoplasty, the stability in the trunk and all the extremities were
lost with even sitting difficulty. After the second surgery, his body
was totally paralyzed, and he could not even move his head. A
respirator was needed all the time. Laminoplasty is not always
reliable and can be a disastrous procedure, unless stability by solid
fusion at the operated site can be perfectly secured.
One of the main causes of this instability is thought to be the
weakness of supporting muscles, which stabilize and support the
cervical spine from the posterior aspect. Most of the short
antigravity muscles are stripped off by laminoplasty. Stabilizing
function of these short monoarticular muscles cannot be restored,
once they are stripped away. Postoperative weakening of the bony
structure would be another factor, which causes instability. In order
to remedy this situation, another approach should be considered.
Yoshida and associates reported a kind of laminoplasty preserving
short monoarticular muscles by unilateral stripping of the
paravertebral monoarticular muscles.279 The important point while
practicing laminoplasty is whether solid bony fusion should be
combined or not. Concomitant bony support from the posterior
aspect should be considered as a combined procedure. Otherwise the
result of laminoplasty may not be long lasting and reliable.
Anterior body fusion is an another recommended procedure.
280-283 Nishimura reported demerits of laminectomy for treatment and
advocated anterior fusion with combined use of halo vest apparatus.
This approach is more reasonable, since anterior fusion can prevent
instability of the most responsible area of the spine, and can also
decompress the affected site. However, one of the problems of this
procedure would be difficulty of immobilization at the fused area,
due to uncontrolled hypertonicity. So, the halo pelvic or halo vest
apparatus have been popularized for immobilization. However,
patients with excessive hypertonicity will not be able to tolerate the
halo-vest apparatus. Fuji mentioned that the balancing function of
the neck might be lost by the use of halo-vest fixation. Another
problem would be occurrence of spondylotic change at the
intervertebral discs adjacent to the fused vertebrae, which is also
induced by the unrelieved excessive hypertonicity. Thus, anterior
fusion also seems to be losing its popularity in treatment of
radiculomyelopathy in cerebral palsy because of these difficulties.
To remedy this situation, Fuji introduced interspinous wiring in
conjunction with the anterior spinal fusion, so that postoperative
period of halo-vest fixation could be shortened.282 Thus, control of
excessive hypermobility in the postoperative period is indeed a
serious problem.
In such a situation, OSSCS can dramatically reduce
abnormal movements due to hyperactivity of the cervical muscles,45,
61 and most of the radiculopathy and radiculomyelopathy can be
treated successfully (Fig. 29AB,109AB, 111ABCD). It also allows
the use of anterior body fusion, without the need for strict external
immobilization and prevents the occurrence of degenerative change
at the adjacent intervertebral disc. So by combined use of selective
spasticity-control surgery and anterior body fusion, exaggerated
hypermobility can be controlled and instability minimized. Thus, by
the use of OSSCS, surgical indications for radiculopathy and
radiculomyelopathy could be broadened enormously with promising
results.
Diagnosis and evaluation
Diagnosis of cervical spondylotic radiculopathy and
radiculomyelopathy in cerebral palsy can be made by almost the
same method as used in non-paralyzed human body without
athetosis. Pain in the neck and upper extremity, sensory loss in the
trunk and all extremities, weakness in the muscles, increased tendon
reflexes, disturbance of fine movements of the fingers, dysuria, and
gait disturbances are carefully examined. Spurling test and
compression test for the neck are also useful in diagnosis. Plane
radiographs, preoperative myelography, MRI, and computed
tomography could also be definitely useful in the diagnosis of the
affected region, and for decision-making regarding the site and type
of operation.
Surgical approaches
Spasticity-control surgery is used as in the basic
spasticity-control procedure. Posterior fusion with fenestration, and
anterior decompression and fusion are combined according to type
and severity of radiculomyelopathy.
Orthopaedic Selective Spasticity-control Surgery
See the clause of "Extensor thrust posture"
By use of this procedure, which is carried out 2-4 weeks
before anterior fusion, symptoms of the radiculopathy and
myelopathy are decreased and intervertebral spaces responsible for
radiculopathy and radiculomyelopathy can be reduced mostly to one
or two levels. Here, Anterior fusion of these levels can be safely
carried out in most of the patients.
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Anterior fusion combined with posterior fusion
Posterior fusion procedure
Anterior Fusion procedure (Fig. 127ABCD)
Fig.127: OSSCS and anterior fusion for treatment
of myelopathy due to excessive athetosis
43-year-old male. quadriplegia
Prior to onset of radiculomyelopathy, he was ambulatory.
127A: He was unable to sit alone and raise his head. All the limb
were paralyzed and sensory loss of 30-80% was observed.
127B: On MRI and CT myelography, marked compression of the
spinal cord from C3toC% was observed.
127C: After OSSCS. Excessive involuntary movements were
controlled and radiating pain and sensory loss disappeared.
He can now stand and walk.
127D: On MRI, there was no finding of compression and no sign
of worsening.
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Laminoplasty
We have no experience of laminoplasty. Laminoplasty could
be indicated in an emergency. In such situations, combined posterior
fusion would be needed to prevent postoperative weakness and
provide stability. We have experiences of posterior fenestration to
reduce the posterior compression, with remarkable improvement in
sensation and recovery of muscle power in the affected upper
extremity including shoulder, elbow. However, instability still
remains at the originally loosened intervertebral spaces and the
tendency for the head to tilt forwards is observed at follow-up.
Postoperative instability due to muscle weakness could be the most
serious problems observed after posterior laminoplasty.
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