Scoliosis is a general term applied to a progressive deforming lateral curve of the spine that may affect different regions of the spine.
Scoliosis is commonly noticed up to the age of 16 years old. Females are more likely than males to have or develop scoliosis; also the severity of the deformity is greater in females than males.
Four main types of curves can be identified in patients that suffer from scoliosis:
Thoracic: it involves a curve at the thoracic level, convex to the right that affects an average of six vertebrae
Thoraco-lumbar: is a curve between the thoracic and the lumbar spine convex to the right that involves an average of 6 to 8 vertebrae
Lumbar: it involves a convex curve to the left in the lumbar spine that affects an average of 5 vertebrae
Double: it involves one curve convex to the right (average of five vertebrae) in the thoracic region and another curve with a left convexity in the lumbar spine.
There are three main types of scoliosis:
- Idiopathic structural scoliosis: may either resolve or progress and the causes are unknown.
This scoliosis tends to worsen until the skeleton naturally stops growing. In children, the deformity is generally the only symptom. Occasionally adults with long-standing deformities experience pain. Depending on the age, the idiopathic scoliosis can be:
- Infantile scoliosis (from birth to three years of age)
- Juvenile scoliosis (from 3 to 10 years old of age)
- Adolescent scoliosis (10 years old until skeletally mature)
- Adult scoliosis (skeletally mature)
- Secondary structural scoliosis: in this type of scoliosis the curve is secondary to an underlying abnormality. There are three underlying causes:
- Congenital abnormality such as hemivertebrae (the absence of half vertebrae)
- Poliomyelitis (the inflammation of grey matter in the spinal cord that causes weakness of the spinal muscles)
- Neurofibromatosis (a genetic disorder that affects the cell growth of neural tissues)
- Compensatory scoliosis: lumbar scoliosis is considered compensatory when the pelvis is tilted laterally (i.e. when the lower limbs are unequal in length or when there is a fixed deformity at the hip joint). Curving the lumbar spine to an angle equal to the pelvic tilt helps to hold the trunk vertically. Usually, the spine itself is not abnormal, the scoliosis disappears upon correcting the pelvic tilt. In cases of long duration, the lumbar scoliosis can become fixed due to shortening of the tissues on the concave side of the curve.
Other deformities of the spine include kyphosis and lordosis, which involve an excessive curvature that is not lateral.
Kyphosis is a general term that describes an excessively posterior convex curvature of the spine. Kyphosis can assume different shapes:
- Round back is used to describe a long, round deformity of the spine
- Hump back is more localized, with a sharp angulation.
The causes of this condition are numerous. Among the most common:
- Tuberculosis of the spinal column
- Fracture of the vertebral body
- Schnermanns disease
Lordosis is an excessive, posteriorly concave curvature of the spinal column that occurs in the lumbar spine. A slight lordotic curve is normal; it becomes pathology when the curve is excessive. In many cases lordosis is the result of a postural deformity.