What is Scoliosis

Scoliosis is defined as a sideways curvature of the spine with the Cobb angle of larger than 10°. This definition is rather a simplified explanation regarding the deformity because in reality, scoliosis is a 3 dimensional deformity which involves coronal (sideways: C-shaped or S-shaped), sagittal (hunched or flat back) and axial (rotation / twisting) planes.

In most of the scoliosis (80-90%), the cause is unknown and therefore is called idiopathic scoliosis. It appears to have genetic predisposition, because the disorder tends to run in families. For idiopathic scoliosis, when the onset happens at the age of 0~3 years, it is called infantile idiopathic scoliosis. In between 3-10 years of age, it is named as juvenile idiopathic scoliosis. Adolescent idiopathic scoliosis, which is the most common type, happens at the age of 10-18 years.

Other less common causes of scoliosis are:

• congenital scoliosis (i.e. birth defects affecting the development of the spine)
• syndromic scoliosis such as Marfan syndrome, Ehlers-Danlos syndrome, Noonan syndrome, Prader Willi syndrome
• neuromuscular disease such as cerebral palsy, muscular dystrophy
• neurofibromatosis
• trauma to the spine
• infection of the spine
• tumour of the spine or spinal cord
• metabolic disorders like osteogenesis imperfecta, rickets

Symptoms

Symptoms and signs of scoliosis include:

• Prominent shoulder blade on one side
• Rib hump
• Uneven shoulders
• Uneven hips
• Uneven waist
• Neck tilt

Parents can easily screen their children when scoliosis is suspected through the Adam’s Forward Bend Test:

The child needs to bend his/her trunk forward with the feet put together, the knees in extension (straight) and the arms hanging. If there is any asymmetry of the left and right side of the back, rib cage or shoulder blade, the test is considered positive. The parents are then advised to bring the child to see a spine surgeon for further examination.

Diagnosis

The examination by spine surgeon involves taking medical history and performing physical examination to look for all the possible causes of scoliosis and to assess the skeletal maturity and recent growth. The diagnosis of idiopathic scoliosis can only be made after excluding all the possible causes of scoliosis.

Whole spine standing X-rays is the standard radiograph used to confirm the diagnosis of scoliosis. The severity of the scoliosis curvature (the Cobb angle) is measured on the same radiograph.

Additional imaging tests such as MRI and CT scan may be needed when the spine surgeon suspects that an underlying condition such as neuromuscular disorders or congenital anomaly could be the cause of the scoliosis.

Treatment 

Treatment of idiopathic scoliosis depends on the skeletal maturity and curve severity (Cobb angle) of the child.

For growing child (skeletally immature), the mode of treatment is summarized in the following table:

Scoliosis	Cobb angle (º)	Treatment
Mild	10-20	Observation
Moderate	20-45	Brace
Severe	>45	Surgery

When the scoliosis is mild (Cobb angle 10-20º), your doctor may just observe the child. Observation means regular follow-up every 4~6 months to monitor for any curve progression. If the curve progresses to moderate scoliosis, Cobb angle 20-45º, the child will be put on a brace.

The purpose of the bracing is to prevent worsening of the curve. It won’t cure scoliosis nor will it reverse the curve.

Braces for scoliosis are generally divided into 2 types: the rigid type and the flexible type.

The brace is to be worn day and night. Most of the daily activities of the child will not be restricted by the brace. For the rigid brace, the child can take off the brace during his/her sports and physical activities. In fact, the child is encouraged to perform stretching and strengthening exercises everyday during this bracing period. The effectiveness of bracing increases with the number of hours per day it’s worn. Parents play an important role in ensuring the child is compliant to his/her brace.

The brace is gradually weaned off after the child stops growing. This occurs when there is no further height increment and the X-rays show Risser stage IV or V (radiographic stages of skeletal maturity).

If the scoliosis is detected when the child’s bones have stopped growing (skeletally mature, age around 16-18years), the risk of curve progression is low. Bracing is not needed for this group of child and surgery will only be advised if the Cobb angle is larger than 50º. When the curve is larger than 50º, there is still risk of curve progression despite skeletal maturity.

Surgery

Surgery is indicated when the scoliosis is severe, i.e. Cobb angle bigger than 45º. The main aim of the surgery is to prevent worsening of curve because severe scoliosis typically progresses with time. Besides that, the surgery also helps in correction of the curve and therefore prevents deterioration of the lung functions, increases abdominal space and achieves better cosmesis with a more balanced trunk, neck and shoulder.

Nowadays, the most common type of surgery performed for idiopathic scoliosis is posterior spinal fusion using pedicle screw system. In this surgery, surgeon connects the vertebrae together using multiple pedicle screws and two rods to correct the deformity. Bone grafts are placed between the connected vertebrae for fusion. The pedicle screws and rods hold that part of the spine straight till the bone grafts and vertebrae fuse together, which typically take place around 4-6 months after surgery.

Posterior fusion surgery is usually performed for post-menarche children. For very young children (less than 10 years old), fusion surgery will lead to ‘crankshaft phenomenon’, a condition where the unfused anterior vertebral bodies continue to grow causing lordosis and bending of the fusion mass. If the scoliosis is progressing rapidly at a young age despite bracing, a growing rod surgery will be performed instead of fusion surgery. The growing rod is fixed to the top and bottom parts of the scoliosis and is lengthened every four to six months as the child grows.

The risk of scoliosis surgery is generally low. Complications of posterior spinal fusion surgery may include bleeding, wound infection, screw-related injury to internal organs, paralysis and implant failure caused by non-union (bone fails to fuse).

What happens if scoliosis is neglected?

Most scoliosis is mild and likely to remain asymptomatic during adulthood. However, especially for severe scoliosis, it may sometimes cause complications if left untreated:

• Lungs and heart failure due to compression of rib cage against the organs
• Chronic back pain. Adults who had scoliosis as children are more likely to have lower back pain than general population.
• Psychosocial impact. Individuals with scoliosis often are unhappy with their appearance, have low self-esteem and emotional stress.