Imaging resulted in a better understanding of the complexities of the scoliotic spine. Plain radiography remains the primary method, but use of multiplanar imaging techniques, such as CT and MRI , have resulted in a greater understanding of the three dimensional nature of scoliosis and enabled underlying abnormalities to be detected with confidence.
Scoliosis is usually described in terms of the side of the convexity, and has been traditionally divided by age at presentation into four main groups: congenital, infantile (< 3 years old), juvenile (3–10 years), and adolescent (> 10 years).
Although 80% of scoliosis is idiopathic, there are clinical features that suggest an alternative diagnosis: a child with an abnormal neurological examination, a painful scoliosis, or other clinical signs of dysraphism will require more than plain radiographs . Neck pain and headache, especially with exertion, and neurological findings such as weakness, pes cavus, and ataxia are also indications for further imaging.
Therefore, the place of radiology in scoliosis management is superficially straightforward; it is to confirm the diagnosis, identify any underlying cause, and monitor the degree of curvature.
In practical terms, this means that most children with a scoliosis require regular review combined with radiographic assessment and measurement of the angle of curvature (Cobb angle). However there are obvious concerns that repeated radiographs result in an excessive radiation burden, especially to the developing breast tissue in girls.
Plain radiography has three roles.
- First, it will confirm the diagnosis and occasionally suggest aetiology, such as a hemivertebra.
- Second, the subsequent monitoring of the child depends largely upon the plain film.
- Third, the plain film provides a method of assessing skeletal maturity.
Magnetic resonance imaging (MRI)
MRI is advocated as the primary imaging modality in the assessment of scoliosis after plain radiography, particularly in the infantile and juvenile forms, where the incidence of spinal cord abnormalities is higher.
MRI is especially good at identifying hydromyelia, syringomyelia, intramedullary tumours, and dysraphic abnormalities such as tethered cords, diastematomyelia, or lipomas.
In this respect, MRI has replaced CT and computed myelography. The importance of careful clinical examination cannot be underestimated. Subtle findings should be thoroughly investigated with MRI and some authors consider atypical curves as positive neurological findings.
Computed tomography (CT)
Details of the bony anatomy can be evaluated further with localised CT and three dimensional reconstructed images through the area of interest. There is a role for CT in the postoperative patient who cannot be imaged appropriately in the MRI environment.