ORTHOPAEDICS OF THE TRUNK ACCORDING TO THE POSITION OF THE LIMBS IN CHILDREN WITH CEREBRAL PALSY

The trunk has an important role in the stability of the gait and in the balance of the posture in sitting position. The key to the examination lies in the appreciation of the mutual infl uences between the trunk and the limbs. The persistence of the automatic reflexes, the installation of an oblique pelvis, the tetraplegia, the hypotonia of the trunk are elements of risk for the development of scoliosis. It is necessary to diagnose these defi ciencies in the first months of the infant’s life, and to follow early kinetic, orthotic or surgical treatment.

The child with cerebral palsy (CP) should be re garded as a morphological entity; one cannot consider only the problems of the pelvis or only the problems of the legs. During the examination, the interactions between lower limbs (LL) and the trunk, and the upper limbs (UL) and the trunk have to be analysed. In the spastic child, the examination of the trunk is often neglected – however, it should be noted that one child in four has a sagittal or frontal spinal deviation. Even a 10° scoliosis curvature can compromise the proper posture when sitting or standing. Any surgery, especially on the LL, should take into account the postural tonus disorder that occurs in the child over 1 year of age. The progressive dissociation of the trunk in relation to the limbs should be considered in the onto-genesis of the infant.

There are four major primitive reflexes concerning automatism:

1. Asymmetric neck reflexes.

2. Symmetrical neck reflexes.

3. Head and trunk mobilization: On turning the head to one side, normally, after the age of 6 months, the shoulders will follow, then the pelvis. In spastic individuals, the child turns in block, not segmentarily.

4. Galant Reflex – its persistence is associated with C-shaped scoliosis [1].

After 1 year of age, if such reflexes persist, this means that there is a lack of attenuation of the spine automatism, presenting the risk of developing scoliosis.

Other factors that intervene in the occurrence of spinal curves: non-acquisition or loss of gait, balance disturbances, sensory disturbances, disturbance of deep sensitivity.

– 21% of children with CP have a 10 ° curvature.

– 6% of children with CP have a 30 ° curvature.

– 1% of children with spastic hemiparesis have a deviation of the spine (therefore, the imbalance of the paravertebral muscles does not have a determinant role).

– 5% of children with spastic diplexia have scoliosis.

– 80 % of children with spastic tetraparesis have scoliosis.

The risk of developing a curvature of the spine is all the greater as the motor deficiency is higher and especially in children without the acquisition of gait.

– The trunk / limb interaction is very important from the point of view of the force ratio;

– The trunk represents 50% of the body weight.

– The head represents 10% of the body weight.

– Upper limbs (UL) represent 10% of the body weight.

– Lower limbs (LL) represent 30% of body weight so they support the remaining 70%.

THE UPPER LIMBS AND THE TRUNK

The paretic disorder of the UL or of the girdles does not lead to the occurrence of scoliosis; there are the lack of walking and the orthopaedic degradation of LL that have a determinant role. In a lateral imbalance of the trunk in orthostatism, UL are used as “stabilizing wings”. In a sitting position, an imbalance of the trunk tends to be corrected by hand support; thus, a correction of the posture will release the UL, which are necessary for the patient’s autonomy. The absence of the parachute reflex means that the UL will not protect the trunk and the persistence of ATNR (Assymmetrical Tonic Neck Reflexes) will not protect it either [2].

THE LOWER LIMBS AND THE TRUNK

The trunk tries to diminish LL distortions, which, in turn, tend to alleviate the trunk imbalance.

In the sagittal plane:

– Hip flexum generates lordosis.

– In the case of a knee in hyperextension by anterior hypertonia, the hip flexion is compensated by the lumbar spine. The trunk is pushed forward, anterior-posterior imbalance occurs. The tenotomy of hip flexors, especially of the anterior rectus femoris, can correct lordosis.

– If the knee is flexed by the retraction of the hamstring muscles, the lumbar lordosis appears in orthostatism, and it is more reduced as compared to the previous case.

– The flexum of the pelvis is partly compensated by lordosis, partly by the knee. The trunk is projected backwards. In sitting position, the lumbar kyphosis develops (the role of the hamstrings).

Kowalski describes a triad leg-knee-spine: the pronation of the foot is the origin of an internal rotation of the LL, which will induce a flexion of the hips and consequently a pelvic anteversion and a lumbar hyperlordosis which may be painful [3].

On the frontal plan:

– The oblique hip is accompanied by a lumbar curvature in 50% of the cases.

The position resembling “the trigger of a riffle” (abduction of one hip and adduction of the other) is often associated with scoliosis and poses two orthopaedic problems, requiring treatment of the spine and of the hips.

Any asymmetry of the angle of abduction of the thigh or the interruption of the cervical-obstruction arch will require early tenotomy of thigh adductors to rebalance the pelvis and avoid scoliosis.

Mixed deformations:

– Kyphoscoliosis is common in postural tonus disorders, with the hypertonia of UL, LL and of the para-vertebral muscles [4].

The monitoring of the spine balance and suppleness, of the sc apular and pelvic belts will be achieved through clinical and radiological examinations, especially during the significant growth period of the vertebral column, i.e. in the first 3 years of life and during the pubertal period. Scoliosis must be identified and treated when the angle of curvature is small, knowing that orthopaedic treatment is difficult to establish due to abnormal contractions, asymmetries, especially in the oblique pelvis.

All forms of scoliosis may be observed, but especially the dorsal and lumbar “C-shaped” curves are characteristic; they go to the opposite side of the pelvic tilt (which is logical, mechanically speaking), but sometimes the curvature is on the same side, drawing the pelvis into the curvature, too (pelvic vertebra).

Once the scoliosis is diagnosed, its reducibility will be assessed clinically and radiologically. The next step should be an assessment of the amelioration of the curve in ventral decubitus (VD) position through flexion-abduction-external rotation of the homolateral thigh. From the sitting position, the action of the position of the LL on the column is checked: moving to a sitting position with LL flexed from the knee joint and oriented laterally to the side of the curve. An elevation with a book under the buttock on the side of the convexity will have the same effect. These methods are effective as long as the curvature is reducible and when the case is far from the point of puberty. Otherwise, a corset will be needed, with or without minerva. These forms of scoliosis should be supervised closely, for they sometimes evolve rapidly before puberty. They may also worsen even after the growth has ended, at a rate of one degree a year.

Consequently:

– Sometimes surgery occurs early, just before the Risser factor closes.

– or, the anterior vertebral column is released so that it might be able to recover in good conditions

– or an extended posterior arthrodesis with pelvic support is used, with reduced, post-surgery immobilisation [4, 5, 6].

CLINICAL AUDIT

It is performed in orthostatism (if possible):

– Balance disturbances are appreciated in frontal and sagittal plane

– Trunk position relative to LL is noted

– Rectification of the trunk, with or without walking aids, is noted

In sitting position:

– The patient is required to straighten out the trunk

– The position of the UL relative to the trunk is assessed

– The position of the UL relative to the head is apprehended

– Lumbar cervical spine will be observed (kyphosis in case of the retraction of the hamstring muscles)

In VD with LL hanging at the edge of the table:

– The possible obliquity of the pelvis is analysed

– The tone of the gluteal muscles is apprehended

In DD:

– The patient is asked to rise to a sitting position (with or without help) and any persistent primitive reflexes are analysed.

Next, examination in lateral tilt: Le Metayer, Vojta [2, 7, 8].

Examination in Collis horizontal suspension and with support on the 4 limbs [8]. Head control is essential. Children without this acquisition will not be able to control their vertebral column.

Special attention should be paid to puberty. In the case of CP, the onset of puberty may be early, normal or late. During this period, the growth will be monitored, by measuring the total height, but also that of the trunk, indicating the pubertal start. These observations will be complemented by Tanner maturity stage s. The statistical increase of the trunk has an ascending and a descending side [9].

Left to grow: Girls Boys

At 10 years: 14cm. 20cm

At 13 years: 4cm 13cm

At 15 years: 1cm. 5cm

In the pubertal period, the vertebral column grows until the suture of the ossification nucleus of the iliac crest, – Risser stage 5, respectively. Vertebral growth is subject to Wolf-Delpech laws, and when scoliosis is over 25 °, the resistance of the vertebral body changes with the asymmetric pressures that will explain vertebral deformation and the evolution of scoliosis [10].

On the other hand, we see an adaptation of the number of sarcomers to the para-vertebral muscles depending on the length of the spinal deformity. In the adult phase, the evolution of scoliosis curves need to be monitored, even for small angulations, because the postural insufficiency remains evident [10, 11].

RADIOLOGICAL EXAMINATION

It is obligatory to include the whole backbone, with the pelvis, in order to analyse both the position of the head relative to the trunk and the position of the coxo-femoral joints. Of real interest are the clichés from the front and the profile, in sitting position and in orthostatism, in order to analyse the deformations: coxa flecta (with the measurement of the cervical diaphyseal angle), kyphosis, scoliosis.

Scoliotic attitude is common in hypotonic diplegias [6].

TREATMENT

Physical therapy aims to decontract the spastic musculature that generates disorders of the spinal column posture as well as to inhibit the reflex tonic activity [11]. Exercises will focus on increasing the amplitude of the hip extension, tightening the buttocks, preventing spinal retraction.

The teenager’s posture disturbances are secondary to musculo-skeletal retractions and to motor control disorders, which must be countered starting with the early childhood [12].

In the older child, who is placed in a wheelchair, the asymmetric or kyphosis postures will be corrected using the expanded sponge, controlling also the height of the leg support. If the latter is too low, it will not allow spontaneous recovery, and, if it is too high, it will induce an undesired hip retro-version [2, 13].

Generally speaking, the therapeutic perspectives are limited and depend on the recovery of the neurological condition. Sometimes, vertebral arthrodesis is required, but this attitude must be well weighed, for in some cases, by depriving the spine of mobility, there is a risk of increased imbalance, especially in spastic patients.

In serious cases, without the possibility of acquiring the gait, a corset is required [14]:

• Since the detection of the deformity

• It should be a Minerva corset

Thus, the correction of the curvature will be ensured, and especially the patient’s quality of life will be improved through

Achieving:

– Hip stabilization,

– Correction of the scoliotic deformity

– Chest mobility, allowing pulmonary development

– The increase in the stature and wei ght of the trunk

In any case, the target is to avoid the development of an asymmetric hip, and in serious cases, the interest is to maintain sitting posture in order to reduce the percentage of patients who maintain only the dorsal decubitus. In conclusion, an early diagnosis is required in the first year of life of a risk prone spine. Tetraplegia, persistence of automatisms, an oblique pelvis, or trunk hypotonia may result in the installation of a spinal curve.