Scoliosis is defined as a lateral abnormal curvature of the spine. That means there is a curvature of the spine to one side.
Though the spine has anterior or posterior curves in different regions, it is a straight line when viewed from the side.
Thoracic and lumbar curves are the most common scoliotic curves.
Severe uncorrected scoliosis can lead to chronic pain, respiratory deficiencies, and decreased exercise capacity in addition to the deformity of the spine.
Types of Scoliosis
It could be classified by many parameters but broadly speaking, there are two types – nonstructural and structural
In nonstructural scoliosis, the spine has a lateral curvature but there is no structural abnormality in the spine. The curvature is in response to habit or a disease process.
The spine is structurally normal with a lateral curvature, no spinal rotation, and no truncal asymmetry.
Following are examples of nonstructural scoliosis
- Prolonged use of a wrong posture. Resolves on lying down.
- In leg-length discrepancy
- Usually goes off on sitting.
- This curve results from trying to avoid pain from an irritated sciatic nerve
- Caused by an infective process such as appendicitis. The body curves in response to the disease or abdominal muscle spasm.
- Underlying psychological component
Structural scoliosis, on the other hand, is the one that involves both lateral curvature and rotation of the vertebrae. Most common type is idiopathic. All other types form the group non-idiopathic.
Following are the types of structural scoliosis
- Most common type
- Classified on the basis of the age when develops – infantile, childhood, adolescence etc.
- Due to abnormal development of the bones of the spine
- For example hemivertebra, paralytic disorders.
- Occurs in older adults
- Degenerative changes lead to the weakening of the normal ligaments and other soft tissues of the spine.
- Arthritic changes may cause an abnormal curvature
- Spine pathology like spine tumors
- Prolonged posturing
Causes of Scoliosis
Causes of nonstructural scoliosis have been discussed.
Here is the list of causes of nonidiopathic structural scoliosis.
- Muscular dystrophies
- Duchenne and Becker’s
- Myotonia dystrophica
- Achondroplasia and hypochondroplasia
- Mesenchymal disorders
- Marfan’s syndrome
- Ehlers-Danlos syndrome
- Spina bifida
- Rheumatoid disease
- Osteoid osteoma
- Eosinophilic granuloma
- Intraspinal tumors like ependymoma, astrocytoma, epidermoid cyst
Clinical Presentation and Diagnosis
As we noted, scoliosis has a multitude of causes and the age span at which it appears is quite wide, varying from newborn to adults.
Therefore, the pathophysiology of different types of scoliosis differs widely and the compensatory changes also depend on the cause and the age of presentation.
Idiopathic scoliosis is the most common type of scoliosis by far and the pathophysiology is discussed at length separately.
Here we only go through general presentations.
The deformity is the main concern of the patients. Sometimes, in cases of mild curves or the balanced curves, the patient may not be aware and scoliosis is found on the examination for some other problem.
Following are the complaints
- Spine deformity
- Deformities of the rib cage
- Tilted pelvis [one hip more prominent than the other]
- Shoulders are not at the same level
- Individuals may appear leaning on one side
- Leg length inequality
In infants the presentation is different. Following should raise the concern in mind of the parents
- Chest Bulge on one side
- Baby lies on one side
- Prominently curved torso to one side
In the initial period, there is no back pain but it usually occurs in long-standing cases.
The physical examination of the patient includes the examination of the spine, pelvis, both lower limbs, and shoulders.
The degree of scoliosis can be measured clinically by scoliometer or radio-radiological images.
Whole spine x-rays and CT scan can help assess the curve, its shape, angle and direction.
Images are typically repeated periodically to assess the progression of the curve and calculating treatment implications.
Some curves might vanish with growth while the majority of them keep growing as the child grows.
Bracing may be effective in halting or slowing the progression.
Thoracolumbosacral orthosis and Milwaukee brace are the braces used in these patients.
Some curves which are severe enough would require surgical treatment which includes correction of the curves and fusion in the corrected position.
In secondary cause, the cause removal if feasible, would cause the correction of the curve. For example hemivertebra.
Specific scoliotic surgeries are discussed in the individual articles.