Scoliosis

What Is Scoliosis?

Scoliosis is a lateral curvature of the spine with vertebral rotation.

Patient 1

Patient 2

Patient 3

What Are Types of Scoliosis?

The various types of scoliosis are:
Postural scoliosis: It is not accompanied by rotational deformity and is fully correctable on lateral bending and recumbency.

Functional scoliosis:

Structural scoliosis: It is not fully correctable on lateral bending or traction. It is of various types:

• Idiopathic the commonest type. According to the age of onset:
  *Infantile - before the age of 3 years.

  *Juvenile - between the age of 3 and 10 years.

  *Adolescent - after the age of 10 years.

• Congenital - It results from defective unilateral segmentation or formation. This is often associated with absence or fusion of ribs.

• Neuromuscular which may be

  *Neurological e.g. Polio, Cerebral Palsy

  *Myogenic e.g. myopathy, muscular dystrophy

• Neurofibromatosis

• Mesenchymal disorders e.g. Arthrogryposis, Morquio's Syndrome, Marfan's Syndrome.

• Traumatic

Congenital Scoliosis

Congenital Scoliosis results from defective unilateral segmentation or formation. This is often associated with the absence of a fusion of ribs. Associated anomalies may be present in the form of a 20% incidence of genitourinary anomalies and 7% incidence of congenital heart disease. Diastematomyelia occurs in 5% of the cases.

Congenital scoliosis are classified by MacEwen as:
Failure of formation

• Partial failure of formation - wedge vertebrae.
• Complete failure of formation - hemivertebrae.Failure of segmentation
• Unilateral failure of segmentation - unilateral unsegmented bar.
• Bilateral failure of segmentation - block vertebrae.

Miscellaneous

Unsegmented bar and multiple hemivertebrae adjacent to one another on the same side are responsible for the progressive curves. The greater the curves in terms of degrees and longer the curve in terms of number of vertebral segments involved, the more likely the curve will progress.

Treatment consists of

• Non-operative treatment: Bracing (e.g. Milwaukee brace) is effective. It is primarily used for the more flexible secondary curves below the congenital one. If the brace maintains the curve in an acceptable position, it is continued. If the curve deteriorates despite faithful brace wearing, fusion is indicated. Bracing is not effective in curves exceeding 50 degrees.
• Operative treatment: A progressive curve must be treated surgically at a very young age. The various options are:

* Fusion in situ

* Cast/halo pelvic correction with fusion

* Epiphysiodesis to prevent growth on the convex side with fusion.

How Is Scoliosis Evaluated?

Evaluation of the spinal curvature involves a study of the anteroposterior and lateral projection of the spine. Estimation of the degree of scoliosis is done by Cobb's method. This method involves the identification of the superior and inferior end vertebrae. End vertebrae are the most superior and inferior vertebrae, which tilt maximally into the concavity of the curve. The angle formed between the perpendiculars drawn to lines along the superior and inferior borders of the superior and inferior and vertebrae respectively indicates the angle of scoliosis.

Common Scoliosis

75% of the scoliosis is idiopathic. Idiopathic scoliosis is one where the etiology is unknown, but, it is probably genetic and the mode of inheritance is complex. Routine evaluation of school children aged 10-14 years have shown an incidence of up to 12%. Smaller curves (up to 15 degrees) and at a younger age, the incidence is equal in males and females. Beyond the age of 10-11 years, 80% of the significant curves are in females.

Idiopathic Infantile Scoliosis:
It represents 1% of scoliosis. It is not associated with vertebral anomalies. Curves less than 37 degrees resolve spontaneously. Curves more than 37 degrees are known to progress and are often associated with plagiocephaly. These curves are treated by a succession of plaster jackets till 3 years of age when a Milwaukee brace can be fitted. If curves are progressive in spite of bracing treatment in the form of fusion is performed.

Idiopathic Juvenile Scoliosis:
This represents 10% of scoliosis cases. It is more common in girls and right-sided curves are common. Treatment is required in curves of more than 25-30 degrees.

Idiopathic Adolescent scoliosis:
This is the commonest type of idiopathic scoliosis. 80% of the patients are females. The presentation is usually subtle and is unnoticed for a long time. Asymmetry of the shoulders, poor fitting of clothes, a rib hump, a prominent shoulder blade draws the attention of the parents. Severe untreated scoliosis produces physiologic cardiopulmonary impairment and unacceptable cosmetic appearance. The natural history varies with the severity of scoliosis. Curves more than 30 degrees progress. Progression occurs commonly during the growth spurt. Curves greater than 50-60 degrees are known to progress even after maturity.

Mild curves (less than 20 degrees) need to be observed for progression. Moderate curves are treated by bracing, the objectives of treatment are:

• To have a stable and balanced, cosmetically acceptable curve till the patient achieves skeletal maturity.
• Avoid over-treatment of the non-progressive curves.
• Avoid iatrogenic loss of lumbar flexibility.

Curves more than 45 degrees cannot be treated by bracing and have to be treated by surgery.

The principle of surgery is to correct the deformity till the spine is compensated and then fusion of the spine. Instrumentation (e.g. Harrington rod) is used to achieve correction and maintain it till fusion occurs. If instrumentation is used in children with a major growth spurt remaining, the patient may require a staged surgical correction.

Pre-surgery patient:

Post-surgery patient: