The spine is the backbone of the human body. It consists of around 33 small bones called vertebrae stacked one over the other. The spinal cord (a group of nerves and nerve cells from the brain) runs through the vertebral column. The spine has the curvature in the forward-backward direction at various places to stabilize the back. But they remain almost straight and vertical in the lateral direction.
What Is Scoliosis?
Scoliosis refers to the abnormal sideways curvature of the spine. The spine looks like the letter S or C. It is a spinal deformity classified under idiopathic congenital musculoskeletal disorders (birth defect of muscles and bone with unknown cause). The angulation of lateral deformity should equal or more than 10 degrees to be termed scoliosis. Sometimes there is vertebral bone rotation and few structural abnormalities associated with scoliosis.
What Are the Types of Scoliosis?
Generally, scoliosis is classified as,
They are the most common form of scoliosis involving both structural rotation and lateral curvature. The structural damage is permanent and needs definitive treatment.
The deformity is temporary with lateral curvature and without rotation. There is no structural abnormality. They are caused due to underlying conditions and are also known as functional scoliosis.
Based on the origin, structural scoliosis can be classified as;
This rare condition affects the fetus inside the womb and is present at the time of birth. However, most cases will need surgical correction.
More than 50 % of patients with scoliosis will have unknown causative factors. Therefore, they are called idiopathic scoliosis, and they appear in the childhood or adolescence stage. Recently, research suggests genetic involvement in idiopathic scoliosis.
Scoliosis can accompany neurological and muscular abnormalities and often present with various other signs and symptoms. Some of the neuromuscular conditions associated with scoliosis are poliomyelitis (poliovirus infection), cerebral palsy (abnormal brain development), achondroplasia (growth disorder with short limbs), paralysis, etc. This condition is also known as myopathic scoliosis.
Age-related scoliosis often occurs later in life due to wear and tear and degenerative changes.
Based on the location,
The curvature is present in the middle back region involving the thoracic spine.
They involve the lumbar spine in the lower back region.
The curvature is quite long, entailing both the thoracic and lumbar spine.
Combined (Double Curve) Scoliosis:
In this case, there are two curves along the length of the spine, combining the thoracic and lumbar spines.
What Are the Causes of Scoliosis?
Although many causes of scoliosis have been identified, most are due to unidentifiable reasons, called idiopathic scoliosis. Congenital scoliosis caused due to a developmental defect in the vertebral column is usually diagnosed early and progresses rapidly. There may be innumerable combinations of developmental anomalies, and the progression of the curve is greatly influenced by it. Diseases of the muscles or nerves may also induce scoliosis, as in the case of neuromuscular scoliosis, which usually progresses relentlessly and requires early diagnosis and surgical intervention. Rarely scoliosis may be associated with some genetic conditions resulting in syndromic scoliosis, diagnosis of which is also paramount for global management of the patient.
Most of the time, the cause is unknown, which results in structural scoliosis. Some of the common causes of non-structural scoliosis are,
How to Diagnose Scoliosis?
The sooner the diagnosis (younger kids), the more the chance to halt the progression of the curve. A thorough history regarding the duration of the deformity, progression, achievement of milestones, school performance, spinal deformity in the family, and other medical histories helps to narrow down the diagnosis. This is followed by a detailed clinical examination of the spine and neurological examination.
1. Physical Examination: Physicians may begin by inspecting the appearance, skin, height, gait, physical development, neuromuscular evaluation (balance, sensation, reflex, stimulation, muscle contractions), symmetry measurement, and bending movements.
2. Imaging Evaluation:
X-Ray: Images obtained in the posterior-anterior view (passing radiation from back to front) determine the angulation of spine curvature. A lateral view radiograph may help to rule out associated spondylosis (degeneration of disc and joints). X-rays also measure the magnitude of the curve (Cobb angle), which may have few degrees of interobserver variability and are used serially to monitor progression along with clinical evaluation.
How to Treat Scoliosis?
The treatment of scoliosis depends on age, angulation of the curvature, type of the condition, and the patient’s choice in asymptomatic cases. Common treatment plans include,
1. Wait and Watch Strategy:
Patients are kept under observation to watch for the progression of the curvature. Most of the cases remain mild and do not progress.
2. Supporting Device:
Usually, when the curvature is greater than 50 degrees, the condition tends to progress at a rate of one degree per year. In such a situation, a brace is used to prevent disease progression.
Surgery is done to correct the deformity and restrict the disease’s progression. Some congenital scoliosis with the potential for rapid progression is treated early or even with prophylactic surgery, where delay leading to severe deformity may represent more surgical risk and poorer outcomes.
Non-fusion Spinal Surgery:
Definitive scoliosis surgery is a fusion surgery where the individual vertebrae are fused with screws and rods, and bone grafts are placed after safe allowable deformity correction, preventing further progression. Since the growth of the spine on the back of the chest (thoracic spine) allows space for the growth of the lung, premature fusion of the thoracic spine before eight to nine years of age prevents full maturation of the lungs due to lack of space and has a significant deleterious effect on the lung function. But unabated deformity of the thoracic spine also compresses on one or rarely both sides of the lung preventing its full development.
In this difficult scenario, a non-fusion spinal surgery is undertaken where spine growth is allowed periodically either with a short duration of spinal surgery with growing rods or from outside with a magnetically controlled growing rod to lengthen the construct, thereby allowing thoracic growth (including lung growth) and correction or maintenance of deformity till patients’ lungs are fully developed and are ready for definitive scoliosis surgery if needed.
Scoliosis is mostly idiopathic. Since it may involve many systems in the body, a multidisciplinary treatment approach can give better results. Bracing gives much discomfort resulting in poor patient compliance. Surgical corrections are associated with numerous complications. Therefore, the overall treatment outcome of scoliosis is not favorable.
Frequently Asked Questions