Scoliosis is a three-dimensional lateral curvature and rotation of the spine. When this condition is left unaddressed, the spinal deformity often worsens over time, leading to complications that affect physical health and daily function. This article focuses on the potential risks and long-term outcomes associated with failing to treat a progressive scoliotic curve.
Curve Progression and Severity
The primary consequence of untreated scoliosis is the continued progression of the spinal curve, measured by the Cobb angle. Progression is highly probable, especially in adolescent idiopathic scoliosis (AIS) while the patient is still undergoing skeletal growth. For curves measuring over 40 to 50 degrees at skeletal maturity, continued worsening throughout adulthood is widely accepted.
Long-term studies show that curves starting between 40 and 50 degrees can progress by an average of 22 degrees over several decades. Even after growth stops, larger curves are subject to constant mechanical stress, leading to an average annual progression rate of about 0.35 degrees. This increased severity results in greater physical deformity, including the visible prominence of a rib hump and unevenness in the shoulders and hips.
Chronic Pain and Functional Limitations
An untreated, progressive curve places uneven pressure on the musculoskeletal structures surrounding the spine. This mechanical imbalance often leads to chronic back pain, which is typically more severe than in the general population. The abnormal alignment strains the paraspinal muscles and ligaments as they constantly attempt to stabilize the body against the curvature.
The uneven weight distribution accelerates wear and tear on the vertebral discs and joints, potentially leading to degenerative conditions like arthritis and spinal stenosis. This structural deterioration leads directly to functional limitations. Reduced flexibility and stiffness can severely limit the ability to perform routine tasks like bending, lifting, or twisting, making activities such as sitting or standing for extended periods difficult.
Compromised Cardiopulmonary Function
In severe, untreated cases, the structural deformity of the thoracic spine directly impacts the function of the heart and lungs. A severe scoliotic curve causes the rib cage to twist and compress, significantly reducing the volume of the chest cavity. This consequence is associated with curves exceeding 70 degrees, and the risk increases substantially for curves over 90 degrees.
The physical restriction limits the lungs’ ability to fully expand, leading to restrictive ventilatory impairment and a decrease in forced vital capacity (FVC). This reduced lung function causes shortness of breath (dyspnea), particularly during physical activity. In the most extreme instances, often with Cobb angles greater than 110 degrees, chronic restriction can lead to respiratory failure, pulmonary hypertension, and strain on the heart.
Severe Neurological and Mobility Consequences
The most severe outcome of untreated scoliosis involves neurological compromise, though this is less common than pain or progression. The abnormal spinal rotation and curvature can cause bony structures to impinge upon the spinal cord or the nerve roots exiting the spine. This nerve compression, known as radiculopathy, can result in radiating pain, numbness, tingling, and muscle weakness in the limbs.
In rare scenarios, pressure on the neural elements can affect fine and gross motor control. Severe, fixed deformities that develop over decades can drastically limit mobility, often requiring the use of assistive devices for walking. Untreated scoliosis in older adults, combined with age-related spinal degeneration, can hasten the progression of the curve and the onset of these debilitating mobility issues.