Congenital Scoliosis
There are many types of congenital scoliosis, varying from a single half vertebra (hemivertebra), an unsegmented bar (this is a single-sided fusion of two or more vertebrae with loss of growth potential on one side of the bar only), to complex types with a combination of congenital vertebral and occasionally, rib deformities.
Dependent on the severity of the abnormality, the external deformity can be limited with little rotation and gibbus height to very severe cases that include disequilibration, severe gibbus and loss of torso height. Congenital abnormalities of the vertebrae should be considered in the presence of any scoliosis that involves severe rigidity. The more severe types, certainly if there is a kyphotic component, may cause neurological disorders in the legs due to compression of the spinal cord.
Paralytic Scoliosis
Various clinical neurological diseases and muscle diseases may give rise to the development of severe scoliosis, which is often accompanied by pelvic tilting. Known examples are poliomyelitis, spina bifida, Duchenne’s muscular dystrophy, spinal muscle atrophy, cerebral palsy and a variety of other rarer diseases.
Often the scoliosis (occasionally accompanied by exaggerated lordosis, or sometimes exaggerated kyphosis) is initially very supple and can be corrected through traction. In the growth phase, progression can be quick and this often continues some time after the growth spurt. In such cases, the scoliosis becomes increasingly rigid and exhibits more rotation.
In patients who are no longer able to walk, the pelvic tilting will become worse, which may make sitting down more difficult. Here, single-sided hip luxation or asymmetric contractures can also play a role. Other problems that may occur include symptoms of pain, often in lower lumbar regions, impaired breathing function (also with the lumbar type due to upward pressure of the abdominal content against the diaphragm) and decubitus.
Other Disorders
There are many types of syndromes that accompany scoliosis. Examples of this are certain collagen deficiency disorders (Marfan’s syndrome or Ehler-Danlos syndrome) and Von Recklingshausen’s neurofibromatosis. Besides examination of the scoliosis itself and neurological examination, one always has to be alert for other abnormalities, e.g. presence of cafe-au-lait spots, which are characteristic of Von Recklingshausen’s or the typical features of long, thin fingers (arachnodactyly) as seen in Marfan’s syndrome.
Physical Examination and Additional Diagnostics
During the physical examination of the back in young people with scoliosis, there should be a more or less supple movement pattern present with considerable individual variation. With severe rigidity of the back one should, as with a thoracic scoliosis to the left, suspect an underlying cause such as an osteoid osteoma (benign small bone tumour) or spinal cord tumour.
Idiopathic scoliosis usually develops just before or at the start of puberty and should be painless at that stage. If symptoms of pain are dominant then it is unlikely that the scoliosis alone is the cause of this; other potential causes should be excluded first. During each examination of the back, a neurological examination of the legs should be conducted to assess strength, sensitivity and reflexes. Another cause may be masked by the presumed idiopathic scoliosis, such as certain spinal cord abnormalities including syringomyelia or tumours of the spinal cord. An MRI scan should be performed if there is doubt concerning the diagnosis of idiopathic scoliosis and also when an abnormality of the spinal cord is suspected.
If, during the physical examination including gibbus measurement, there are indications of structural scoliosis then X-ray examination should be carried out, during which the scoliosis (and kyphosis) can be expressed in measure and number. This measurement is carried out according to Cobb’s method. According to the criteria of the Scoliosis Research Society, scoliosis means a Cobb’s angle of more than 10°. Through successive measurements, both externally and through x-ray examinations, it can be determined whether the scoliosis is progressive or stationary. Treatment is nearly always indicated in progressive scoliosis to avoid development of a large deformity of the spine.
Often scoliosis is discovered by the school doctor who is capable of conducting a proper gibbus measurement. With a gibbus height measurement, a height difference between left and right of more than 1 cm or a rotation measurement of over 3° means that scoliosis is likely.
Management
It is of key importance to refer a child to an orthopaedic surgeon at an early stage. The specialist has to assess whether the child should be treated for their abnormality. An estimation of the risk of progression plays a large role. In general, the following applies to idiopathic scoliosis, the risk of progression of the scoliosis is greater the younger the child is, and the greater Cobb’s angle is measured on the x-ray image, when the scoliosis is initially discovered. For example, the chance of progression of scoliosis of 30° in a girl with a skeletal age of 10 years will be 90-100%. The chance of progression of scoliosis of 30° in a girl with a skeletal age of 15 years will be only 20-30%. The 10 year old girl will have to be treated with a redressing corset (brace), combined with exercise therapy. This is the only non-operative therapy to be likely to prevent progression of the scoliosis in most cases. With the older girl, a watch and wait approach can be adopted to see if there will indeed be any deterioration and often treatment is not necessary. Since progression of the scoliosis can be avoided by treatment with a brace in 80% of patients, early referral is important. Brace treatment is indicated in scoliosis with a Cobb’s angle of between 25 and 30° plus proven progression, and an angle between 30 and 45° when the child is expected to continue growing for a minimum of 1 year.
An exact limit, in terms of the external measurement of the gibbus height and the gibbus rotation, above which the patient should be referred, is not known. However, it is advisable to re-evaluate the patient after 3 to 6 months if the gibbus height is 1 cm in the thoracic region, 0.8 cm in the lumbar region and the gibbus rotation measures 3° to 7°. Referral is indicated for measurements above this.
Operative treatment is indicated in idiopathic scoliosis with a Cobb’s angle of 45° or more. One must bear in mind that not only the x-ray image determines the choice between a conservative or operative treatment. The rotational deformity is also important when making this decision, as well as the potential progression and presence of symptoms.
In non-idiopathic scoliosis, an operative treatment can be opted for earlier. In some congenital types of scoliosis, for example a fused hemivertebra without involvement of neighbouring vertebrae or single-sided fusion of 2 or more vertebrae, it is certain that severe progression of the scoliosis will take place. An operation performed early on in the patient’s life is then required, involving fixation of some vertebrae and terminating growth, to avoid the development of a severe back deformity.
The operative treatment of severe scoliosis can be carried out in different ways. Until recently, thoracic scoliosis was operated on mainly from the back, during which correction takes place using an instrument system, such as the Cotrel-Dubousset or Isola system. During this procedure, special hooks are placed onto the vertebral arches or screws inserted into the pedicles (connection between spinal body and vertebral arch), after which, these are linked on the left and right with a rod. By rotating the rod, translation techniques and distraction and compression, correction of the scoliosis is achieved.
Nowadays, operations of the thoracic spine are increasingly performed at the front, with screws inserted in a transverse direction into the spinal bodies, which again are linked with a rod. Thereafter, correction can be achieved by compressing the convexly positioned screws.
In the thoracolumbar spine, these techniques have been applied for some time now by approaching from the ventral side. A technique using two screws per spinal body and two rods on the side of the vertebrae is currently being developed so that greater stability is achieved compared with using one screw per vertebra.
For long scoliotic curvatures in patients with neuromuscular diseases, for example cerebral palsy or Duchenne’s muscular dystrophy, the complete spine – from the upper thorax down to the sacrum – needs to be operated on in order to avoid scoliosis development above or below the operative area.
The most important aim of these operational techniques is to achieve spondylodesis. For this, bone originating from the spinous processes and vertebral arches of the operated area, supplemented with bone from the posterior pelvic crest or artificially produced bone substitute (tricalcium phosphate) is used to place over the vertebral arches. The vertebral arches are trimmed beforehand. This means the removal of the cortical bone using gouges or pliers, so that the bleeding spongy bone is exposed and optimal attachment of the applied bone on the vertebral arches can take place to form a solid bone plate (spondylodesis) without loss of correction. Nowadays, fixation techniques are so good that following these operations, external fixation with a corset is hardly required anymore and the patient can move the non-operated part soon after. In the last few decades, operations have becomes safer by monitoring the spinal cord function during the operation and by recycling the lost blood using a so-called cell saver.