Scoliosis is classified as a musculoskeletal disorder (MSD), a condition that affects the body’s structural framework and capacity for movement. The disorder is characterized by an abnormal, three-dimensional curvature of the spine, where the vertebrae deviate from their natural alignment. This spinal deformity impacts the skeletal system, which is the primary domain of musculoskeletal health. Examining the specific structural changes it causes helps confirm its classification within this group of disorders.
Defining Musculoskeletal Disorders
Musculoskeletal disorders encompass conditions that affect the human musculoskeletal system, including bones, joints, ligaments, muscles, nerves, and soft tissues. These disorders relate directly to the body’s physical structure and the mechanics of movement. Symptoms often involve pain, stiffness, and a decreased range of motion, which can impair mobility and functional abilities.
MSDs can arise from various factors, such as repetitive strain, physical exertion, or degenerative processes. Scoliosis fits this definition because it is a structural deformity of the spinal column, a foundational component of the skeletal system. The spinal curve directly affects the alignment and function of the bones, joints, and surrounding muscles.
The Structural Characteristics of Scoliosis
Scoliosis is a complex, three-dimensional change in spinal geometry, not simply a sideways bend. The deformity involves a lateral curvature in the coronal plane (side-to-side deviation often seen on X-rays). Concurrently, the vertebrae twist or rotate along the spine’s vertical axis, a rotational component that is a defining feature of the condition.
This twisting also causes changes in the sagittal plane (the side view), impacting the normal front-to-back curves of the spine. The rotational element frequently results in a noticeable prominence of the ribs on one side of the back, often referred to as a rib hump. These combined movements create a helical, or spiraling, deformity of the vertebral column.
Diagnosis and monitoring rely on measuring the Cobb angle, the standard metric used by clinicians. This angle is determined by identifying the most tilted vertebrae at the top and bottom of the curve, known as the end vertebrae. The angle formed by the intersection of lines drawn along these vertebrae is measured in degrees.
A Cobb angle measurement of 10 degrees or greater on a standing X-ray is the threshold for a formal diagnosis of scoliosis. While the Cobb angle is an effective two-dimensional measurement, it must be interpreted within the context of the spine’s three-dimensional rotation. The severity of the disorder increases with the Cobb angle.
Classification and Etiology of Scoliosis
The diverse causes of spinal curvature lead to different classifications of scoliosis.
Idiopathic Scoliosis
This is the most common form, accounting for approximately 80% of cases, where the origin of the spinal deformity remains unknown. This type is categorized based on the age of onset, such as Adolescent Idiopathic Scoliosis (AIS), which appears between the ages of 10 and 18.
Congenital Scoliosis
This form is present at birth and results from malformations of the vertebrae during embryonic development. This involves issues like vertebrae failing to form completely or fusing together improperly, leading to an abnormal skeletal structure. The severity often depends on the type and location of the vertebral malformation.
Neuromuscular Scoliosis
This classification occurs when the spinal curve is a direct consequence of underlying neurological or muscular diseases. Conditions such as cerebral palsy, muscular dystrophy, or spina bifida can cause muscle weakness and imbalance that fail to support the spine correctly, resulting in a structural curve. Regardless of the specific cause, the condition is fundamentally a disorder of the skeletal system, affecting the spine’s structural integrity and mechanics.
Current Management Approaches
The management of scoliosis is based on a tiered approach, with treatment decisions guided by the magnitude of the Cobb angle and the patient’s skeletal maturity.
For mild curves, measuring less than 20 to 25 degrees in a growing patient, the initial approach is observation. This involves regular monitoring with physical exams and X-rays to check for curve progression as the individual grows.
When a curve progresses or measures between 25 and 40 degrees in a growing adolescent, non-surgical interventions, such as bracing, are recommended to halt the progression. A custom-fitted brace is designed to apply corrective pressure to the spine and is worn full-time until the patient reaches skeletal maturity. This external support aims to prevent the curve from worsening to a level that would require surgical correction.
Physical therapy methods, particularly the Schroth method, are frequently used alongside bracing or as a standalone treatment for mild-to- moderate curves. This approach uses personalized, three-dimensional exercises that focus on rotational angular breathing and specific postural correction to de-rotate, elongate, and stabilize the spine. The exercises aim to improve muscular symmetry and teach the patient to actively correct their posture.
Spinal fusion surgery becomes the primary treatment option for severe curves, exceeding 40 to 50 degrees, especially if they are continuing to progress. The surgical procedure involves permanently connecting two or more vertebrae to prevent movement between them, which stops the curve from worsening. Metal rods, screws, and hooks are used to hold the spine in a straighter position while the bone graft fuses the vertebrae together.