Scoliosis is defined as an abnormal, three-dimensional curvature of the spine that deviates sideways, often presenting as an S- or C-shape. While the condition is most commonly diagnosed during adolescence, the curvature can indeed worsen after a person stops growing. Progression in adulthood is driven by factors different from those during the teenage years, manifesting either as the worsening of a curve that originated in childhood or as a new curvature that develops later in life. Understanding the mechanics behind this adult progression is important for effective long-term management.
How Skeletal Maturity Affects Progression Risk
The risk of scoliosis worsening is highest during periods of rapid growth, such as the adolescent growth spurt. For most people with adolescent idiopathic scoliosis (AIS), the spinal curve tends to stabilize significantly once the skeleton reaches full maturity. Doctors determine this point by evaluating the closure of growth plates, which signals the end of bone elongation and eliminates the primary mechanical driver for curve progression.
Curves that are mild to moderate at skeletal maturity have a relatively low likelihood of substantial worsening over a lifetime. This stabilization occurs because the vertebrae have fused and hardened, making them far more resistant to the forces that cause rotational and lateral deformation. However, this stability is not a guarantee, and other forces can come into play as a person ages.
Specific Factors That Cause Adult Curve Worsening
Progression after growth stops is driven by the curve’s initial size and the natural wear and tear of the spine over time. The magnitude of the curve at skeletal maturity is a major predictor of its future behavior. Curves measuring less than 30 degrees on an X-ray are considered low risk for future progression.
Curves exceeding this threshold, particularly those over 40 to 50 degrees, carry a much higher risk of continued worsening throughout adulthood. This progression is not growth-driven but results from mechanical failure under the constant force of gravity. A large curve is inherently unstable, and asymmetric loading on the vertebral bodies and discs causes slow, relentless progression.
In older adults, the primary mechanism for curve worsening shifts to age-related degeneration, often beginning after age 40 or 50. This process involves the gradual loss of height in spinal discs and the development of arthritis in the facet joints. Uneven degeneration destabilizes the spine, leading to the progression of a pre-existing curve or the development of de novo degenerative scoliosis. Osteoporosis, which weakens bone structure, can further contribute by causing small, asymmetric wedging fractures in the vertebrae, accelerating the curvature.
Monitoring and Non-Surgical Management Strategies
Regular observation is fundamental to managing adult scoliosis, especially when risk factors for progression are present. Monitoring involves periodic X-rays to accurately measure the Cobb angle, which quantifies the degree of spinal curvature. Clinicians consider a change of 5 degrees or more between appointments to be a significant progression warranting a re-evaluation of the management plan.
Non-surgical strategies focus on alleviating pain, improving function, and slowing the rate of curve worsening. Specialized physical therapy programs, such as the Schroth method, are often recommended to teach patients how to actively correct posture and strengthen core muscles. These exercises aim to improve muscular balance and spinal stability.
Pain management often utilizes nonsteroidal anti-inflammatory drugs (NSAIDs) or localized injections for severe discomfort. Custom-designed spinal braces can provide external support, aiming to reduce pain and potentially slow progression by limiting asymmetric loading. Lifestyle adjustments, including maintaining a healthy weight and engaging in low-impact activities, are also encouraged to reduce stress on the spinal column.