Idiopathic Scoliosis

Description of the Disease

Idiopathic scoliosis is a three-dimensional deformity of the spine with no identifiable cause. It is believed to result from multiple contributing factors, including genetic predisposition, abnormalities in growth hormone secretion, altered melatonin production by the pineal gland, connective tissue and muscle dysfunction, and other biological factors.

In idiopathic scoliosis, an imbalance in muscle activity around the spine causes the vertebrae to rotate and curve sideways. As the condition progresses, the pelvis may tilt and rotate in an attempt to compensate for the spinal deformity, making one leg appear shorter than the other. In thoracic scoliosis, rotation of the vertebrae causes the ribs to protrude, forming a rib hump and deforming the chest wall. Severe cases may reduce lung capacity and eventually lead to cardiopulmonary complications.

Idiopathic scoliosis is classified according to the age at onset:

• Infantile scoliosis: Birth to 3 years of age.
• Juvenile scoliosis: 4–10 years of age.
• Adolescent scoliosis: 10–20 years of age.

According to the location of the spinal curve, idiopathic scoliosis may be classified as:

• Thoracic.
• Double thoracic.
• Triple curve.
• Lumbar.
• Thoracolumbar.
• Double major (S-shaped).

Symptoms

The primary sign of idiopathic scoliosis is an abnormal curvature of the spine, which is often visible on physical examination.

Common clinical findings include:

• Uneven shoulders or waist.
• Prominence of the muscles on one side of the lower back when bending forward.
• Pelvic tilt or rotation while standing.
• A rib hump on the affected side of the chest in thoracic scoliosis.
• Trunk asymmetry.

The condition is most commonly detected between 4 and 8 years of age. The spinal curvature usually progresses slowly at first, by approximately 1–2 degrees per year, but progression often accelerates during the adolescent growth spurt—typically between 11 and 12 years of age in girls and 13 and 14 years in boys. During this period, the curve may worsen by up to 10 degrees per year. Progression usually slows or stops once skeletal maturity is reached, generally around 14 years of age in girls and 16 years in boys.

Infantile scoliosis typically appears after 6 months of age, is more common in boys, and usually involves a left-sided thoracic curve. Approximately 85% of infantile cases resolve spontaneously or do not progress. Juvenile scoliosis is more frequently diagnosed in girls.

Diagnosis

Diagnosis is based on the patient’s medical history, physical examination, and spinal X-rays.

Radiographic evaluation includes measurement of the Cobb angle, assessment of vertebral rotation, and evaluation of skeletal maturity, often using pelvic bone development (such as the Risser sign), which helps estimate remaining growth potential and the likelihood of curve progression.

Treatment

There is no treatment that can cure the underlying cause of idiopathic scoliosis. Management depends primarily on the severity of the spinal curvature and the patient’s remaining growth potential.

For mild to moderate curves (approximately 20–25 degrees), treatment focuses on maintaining muscle strength through physiotherapy and exercises. Swimming and other physical activities may improve overall fitness but have only a limited effect on preventing curve progression.

Bracing may be recommended for growing children with progressive curves to slow further progression and reduce the likelihood of surgery.

A leg-length discrepancy greater than 15–20 mm may be corrected with a shoe lift when appropriate.

Firm mattresses, bed boards, and massage have not been shown to prevent progression of scoliosis. Spinal manipulation or manual therapy is generally not recommended as a treatment for idiopathic scoliosis because it has not been shown to correct the deformity.

Surgical treatment is generally considered for curves measuring 45–50 degrees or greater, particularly when the deformity is progressive or causes significant imbalance. The goal of surgery is to correct and stabilize the spinal curvature, restore shoulder and pelvic alignment, and prevent further progression. This is typically achieved using spinal instrumentation and fusion with metal rods and screws.

Source | Author Doctor Nikas Samuolis, reviewed by Prof. Virginijus Šapoka | Vilnius University | Faculty of Medicine | Head of the Department of Internal Medicine, Family Medicine, and Oncology