Scoliosis, an abnormal lateral curvature of the spine, is often associated with children and adolescents. However, it can develop later in life. This adult-onset form is commonly referred to as degenerative scoliosis. Unlike forms that arise during growth, adult scoliosis is tied to the aging process of the spinal structures in a skeletally mature adult.
Defining Adult Scoliosis
Adult scoliosis is not a single diagnosis but a category separated into two distinct types based on the spine’s history. The first type involves the progression of a curve that originated in youth, most often Adolescent Idiopathic Scoliosis (AIS), which begins to worsen in adulthood due to age-related changes. The curve’s instability is exacerbated by degeneration over time.
The second type is known as De Novo scoliosis, meaning “from the beginning.” This describes a curvature that develops entirely after skeletal maturity in a previously straight spine. This condition is the result of degenerative changes and presents in individuals over the age of 40, with prevalence increasing in older populations. The underlying cause and subsequent treatment approach differ substantially between these two categories.
Primary Mechanisms of Degenerative Scoliosis
The core mechanism driving De Novo scoliosis is the asymmetrical deterioration of the spine’s supporting components. The intervertebral discs, which act as cushions between the vertebrae, begin to lose height and hydration unevenly. This asymmetrical disc collapse is a primary factor that forces the spine to tilt sideways.
In conjunction with disc changes, the small facet joints located on the back of the vertebrae develop arthritis. This degeneration causes instability and further contributes to the spinal column’s collapse toward one side. The combined effect of uneven disc narrowing and arthritic joint instability results in the lateral curve characteristic of scoliosis, primarily affecting the lumbar spine. Loss of bone density, such as that seen in osteoporosis, can also contribute to the collapse and subsequent curvature by weakening the vertebral bodies.
Symptoms and Functional Limitations in Adults
Unlike the adolescent form, which is often painless, adult degenerative scoliosis frequently presents with significant and debilitating symptoms. The mechanical and structural instability causes chronic low back pain, often referred to as axial pain, which is localized to the lower spinal region. This pain arises from the strain on the surrounding muscles and ligaments that are constantly working to stabilize the unbalanced spine.
A more concerning symptom is radiating leg pain, known as radiculopathy or sciatica, which occurs due to nerve root compression. The degenerative process and sideways curvature can narrow the spinal canal or the small openings where the nerves exit, a condition called spinal stenosis. Patients may also experience neurogenic claudication, where leg pain, numbness, or weakness worsens with standing or walking but finds relief when sitting or bending forward. The spinal imbalance can also lead to difficulty standing upright for long periods, limiting walking endurance.
Diagnosis and Treatment Approaches
The initial diagnosis of adult scoliosis involves a thorough patient history and physical examination to assess posture, flexibility, and neurological status. Diagnostic imaging is then used to confirm the presence and severity of the curve, which must measure 10 degrees or greater on a standing X-ray. Magnetic Resonance Imaging (MRI) is often used to visualize soft tissues, such as intervertebral discs and nerves, helping identify the source of any nerve compression.
The management of adult degenerative scoliosis begins with non-surgical, conservative treatments. These options focus on alleviating pain and improving function rather than physically correcting the curve. Non-surgical approaches include physical therapy to strengthen core muscles and improve flexibility, anti-inflammatory medications, and targeted spinal injections. Epidural steroid injections can be used to deliver anti-inflammatory medicine directly to compressed nerve roots, providing temporary relief from radicular pain.
Surgery is reserved for cases where non-operative treatments fail to manage severe, debilitating pain or when the patient exhibits progressive neurological deficits. Surgical goals involve decompressing the pinched nerves and stabilizing the spine through fusion to prevent further progression of the curve. Procedures may range from localized decompression to extensive spinal fusion across multiple segments, aiming to restore better spinal alignment and provide long-term stability.