[Scoliosis Basics & Fundamentals 06] Adult Degenerative Scoliosis: Causes and Symptoms

Adult Degenerative Scoliosis: Causes and Symptoms

Introduction

Adult degenerative scoliosis is a form of spinal deformity that develops or progresses during adulthood as age-related changes affect the intervertebral discs, facet joints, vertebral structures, and supporting tissues of the spine. It is also commonly called degenerative lumbar scoliosis or de novo scoliosis when the curvature develops in a previously relatively straight spine during adulthood. Unlike adolescent idiopathic scoliosis, which usually begins during childhood or adolescence, adult degenerative scoliosis is closely associated with progressive degeneration of the structures that normally maintain spinal alignment. [1][2]

For many patients, the condition develops gradually. At first, an individual may notice occasional lower-back stiffness or fatigue after standing for a long time. Over time, however, asymmetric disc degeneration and joint arthritis can alter the alignment of the lumbar spine. This may produce a measurable coronal curvature, changes in lumbar lordosis, trunk imbalance, and narrowing of the spaces through which spinal nerves travel. [1][3]

Adult degenerative scoliosis is therefore more than simply an age-related "curve" in the spine. It is a three-dimensional spinal alignment disorder that can involve coronal curvature, vertebral rotation, sagittal imbalance, pelvic compensation, and degenerative narrowing around the spinal nerves. [2][4]

For patients and families, this distinction is important because the symptoms of adult degenerative scoliosis may come from several interacting sources. Pain may arise from degenerating discs or facet joints, while leg pain, numbness, or weakness may result from spinal stenosis or nerve-root compression. A person's symptoms therefore cannot be predicted from the Cobb angle alone. [1][3]

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What Is Adult Degenerative Scoliosis?

Adult degenerative scoliosis generally refers to a structural spinal curvature that develops in adulthood as a consequence of degenerative changes in the spine. The condition most often affects the lumbar spine, although degeneration and deformity can influence alignment across multiple spinal regions. [1][2]

The Scoliosis Research Society describes adult degenerative scoliosis as a type of adult scoliosis that develops because of degeneration of the intervertebral discs, arthritis of the facet joints, and collapse or wedging of disc spaces. It is commonly associated with loss of normal lumbar lordosis when viewed from the side. [1]

Unlike adolescent idiopathic scoliosis, adult degenerative scoliosis is often associated with symptoms caused by degenerative spinal disease. These may include lower-back pain, stiffness, leg pain, numbness, and symptoms associated with spinal stenosis. [1][3]

The term de novo scoliosis is sometimes used because the curvature develops during adulthood rather than representing a continuation of a clearly established adolescent curve. However, not every adult with scoliosis has a newly developed curve. Some adults have adolescent idiopathic scoliosis that has persisted and progressed during later life. Distinguishing these conditions can be clinically important. [1]

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Adult Degenerative Scoliosis vs. Adult Idiopathic Scoliosis

There are two broad pathways by which an adult may have scoliosis.

Adult idiopathic scoliosis

This is generally a continuation of scoliosis that began earlier in life, often during adolescence. A person may have had a known spinal curve for decades, or an old curve may only become recognized when symptoms develop later in adulthood. Degenerative changes can subsequently increase the magnitude of the curve and contribute to symptoms. [1]

Adult degenerative or de novo scoliosis

This develops later in life as asymmetric degeneration alters spinal alignment. The process commonly involves intervertebral disc degeneration, facet-joint arthritis, asymmetric disc-space collapse, and changes in lumbar lordosis. [1][2]

The distinction is not merely academic. The underlying anatomy, pattern of degeneration, neurological symptoms, and treatment considerations may differ between long-standing idiopathic scoliosis and a newly developed degenerative curve. [1][3]

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What Causes Adult Degenerative Scoliosis?

1. Intervertebral Disc Degeneration

One of the central mechanisms in adult degenerative scoliosis is intervertebral disc degeneration.

Between most vertebral bodies are intervertebral discs that provide cushioning and contribute to spinal movement and load distribution. With aging, discs can lose hydration and structural integrity. Disc height may decrease, and the degeneration may not occur symmetrically from one side to the other. [2][5]

When one side of a disc space collapses more than the other, the vertebral segment can gradually tilt. When this process occurs at multiple levels, the combined effect can produce a progressive coronal curvature. This is one reason adult degenerative scoliosis is frequently associated with asymmetric disc-space narrowing and wedging. [1][2]

Disc degeneration can also alter the normal sagittal profile of the lumbar spine. Loss of lumbar lordosis may cause the trunk to shift forward, increasing the demands placed on the spinal and pelvic muscles needed to maintain an upright position. [2][4]

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2. Facet Joint Osteoarthritis

The facet joints are small paired joints located at the back of the vertebral column. They help guide spinal movement and contribute to stability.

As people age, the facet joints may develop osteoarthritic changes. Cartilage can deteriorate, joint surfaces may become irregular, and osteophytes or bone spurs may develop. [5]

Facet-joint degeneration can contribute to both mechanical back pain and narrowing of spaces around spinal nerves. When degeneration is asymmetric, it can also contribute to progressive changes in spinal alignment. [1][5]

This means that adult degenerative scoliosis is rarely caused by one isolated structure. Instead, the condition usually reflects interaction among discs, facet joints, vertebral alignment, muscles, ligaments, and the pelvis. [2][3]

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3. Asymmetric Disc Collapse

A particularly important feature of degenerative scoliosis is asymmetric disc collapse.

Imagine a lumbar disc that gradually loses height. If the loss of height occurs relatively evenly, the primary result may be generalized loss of disc height. If the collapse is greater on one side, however, the vertebral bodies can tilt toward that side. [1][2]

When several adjacent levels develop this type of asymmetric degeneration, the individual changes can combine into a larger structural curve.

This process may also produce:

• Lateral vertebral translation
• Foraminal narrowing
• Segmental instability
• Vertebral rotation
• Progressive coronal imbalance
• Changes in lumbar lordosis

These structural changes help explain why adult degenerative scoliosis can produce both visible posture changes and neurological symptoms. [2][3]

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4. Loss of Lumbar Lordosis and Sagittal Imbalance

The spine needs to maintain a balanced relationship between the head, thorax, pelvis, and lower extremities.

Lumbar lordosis is the normal inward curvature of the lower back when viewed from the side. Degenerative disc disease and other age-related changes can reduce this curvature. [1][4]

When lumbar lordosis decreases substantially, the trunk may shift forward. The body can initially compensate by rotating the pelvis backward, extending the hips, or flexing the knees to maintain an upright posture. [4]

These compensatory mechanisms can eventually become physically demanding.

Patients may describe:

• Difficulty standing completely upright
• A tendency to lean forward
• Back-muscle fatigue
• Difficulty walking for extended periods
• Relief when sitting or leaning forward

This illustrates why adult spinal deformity should be evaluated in both the coronal plane and sagittal plane, rather than by measuring only the lateral curvature. [2][4]

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5. Osteoporosis and Vertebral Compression Fractures

Bone health can also influence spinal alignment in older adults.

Osteoporosis reduces bone mass and weakens the structural strength of vertebrae. Vertebral compression fractures can change vertebral shape and alter the alignment of the spinal column. [4][6]

A compression fracture may produce a localized kyphotic deformity rather than classic degenerative scoliosis, but multiple fractures or asymmetric vertebral collapse can contribute to a broader spinal deformity. [4]

For this reason, evaluation of an older adult with a newly developing spinal deformity may include consideration of bone health, especially when there is a history of osteoporosis, low-trauma fracture, or significant height loss. [4][6]

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6. Age-Related Changes in the Spine

Aging does not automatically cause symptomatic scoliosis.

Many adults have disc degeneration or facet arthritis visible on imaging without experiencing significant pain. However, in some individuals, progressive degeneration can contribute to spinal deformity and neurological compression. [5]

This distinction is important because an X-ray or MRI may show substantial degenerative changes in a person who has relatively few symptoms, while another patient with less dramatic imaging findings may experience substantial pain or disability.

Therefore, imaging findings should always be interpreted alongside the patient's symptoms, physical examination, functional limitations, and neurological findings. [1][3]

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What Does Adult Degenerative Scoliosis Look Like?

The physical appearance of adult degenerative scoliosis can vary considerably.

Some patients have a relatively subtle curve that is difficult to see externally. Others may develop noticeable asymmetry of the shoulders, waist, pelvis, or trunk. [1]

Possible visible findings include:

• Uneven shoulders
• Uneven waist contours
• Pelvic asymmetry
• Trunk shift
• A visible lumbar curve
• Prominence of one side of the lower back
• Forward-leaning posture
• Difficulty maintaining an upright position
• Reduced posture symmetry

However, visible asymmetry does not establish the diagnosis by itself. A structural spinal deformity requires appropriate clinical assessment and, when indicated, radiographic evaluation. [1][7]

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Common Symptoms of Adult Degenerative Scoliosis

1. Lower-Back Pain

Low-back pain is one of the most common symptoms associated with adult scoliosis. Degenerative discs, facet joints, muscular fatigue, mechanical instability, and altered spinal alignment can all contribute to pain. [1][2]

Pain may be localized to the lower back or may occur around the apex or concavity of the spinal curve. Some patients experience increased discomfort after prolonged standing or walking, while others notice symptoms during particular movements or activities. [2]

Importantly, not every adult with degenerative scoliosis experiences pain. The presence of a radiographic curve does not necessarily mean that the curve itself is the source of pain. [1][5]

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2. Back Stiffness

Stiffness is another common complaint.

Degeneration of the intervertebral discs and facet joints can reduce normal segmental motion. Muscles surrounding the spine may also remain active for longer periods to compensate for altered alignment and maintain an upright posture. [1][5]

Patients may therefore describe their back as:

• Stiff after waking
• Tight after prolonged sitting
• Fatigued after standing
• Difficult to straighten after activity

Persistent or progressively worsening stiffness should be assessed in the broader context of spinal degeneration and deformity. [1]

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3. Leg Pain and Sciatica-Like Symptoms

Adult degenerative scoliosis can be associated with spinal stenosis, which occurs when the spaces available for the spinal cord or nerve roots become narrowed.

Degenerative changes such as disc-space collapse, facet hypertrophy, osteophyte formation, and changes in spinal alignment can reduce the available space for nerve roots. [1][5]