Introduction
Degenerative scoliosis in adults represents a complex spinal condition, often considered one of the most difficult to treat due to its variability. Mainly observed after the age of 40, it is frequently associated with degeneration of the intervertebral discs, leading to structural misalignment of the spine. In older women, osteoporosis, characterized by loss of calcium in the vertebrae, is often a contributing factor.
This condition causes a loss of structural stability of the spine, making it unbalanced. This imbalance induces changes in the distribution of forces acting on the spine. The steeper the scoliotic curve, the more these changes cause accelerated degeneration of the spine, creating a vicious cycle where the deformity amplifies the imbalance, leading to more deformity.
When the spine has an S-curve when viewed from the front, it is called scoliosis. This deformity can also affect the normal curve of the spine when viewed from the side, compromising the curves needed to maintain balance. Some scoliosis patients even lose the normal curves of the spine.
Our body, in its natural quest for balance, seeks to keep the head directly above the middle of the pelvis. Thus, a longer leg or a curvature in one part of the spine will cause a tilt of the pelvis, inducing an opposite curvature to keep the head centered. The scoliotic curve has a convex and concave side, and the body adjusts the rest of the spine to balance the head above the pelvis.
The concave region of the curve experiences more joint, facet, and possibly nerve root compression, leading to pain, weakness, and numbness in the legs, known as radiculopathy. The dorsal unit, composed of ribs and supported by intercostal ligaments, undergoes anterior-posterior deviation, affecting pulmonary and cardiac function.
Causes of Degenerative Scoliosis in Adults
- Aging: The natural aging process can lead to degeneration of the intervertebral discs, loss of disc height, and changes in the joints of the spine, contributing to the development of degenerative scoliosis.
- Facet Osteoarthritis: Osteoarthritis of the facet joints, which are the small joints between the vertebrae, can lead to cartilage wear, osteophytes (bony growths), and asymmetry, contributing to degenerative scoliosis.
- Degeneration of Intervertebral Discs: Degeneration of the intervertebral discs, with the loss of their ability to retain water and absorb shock, can lead to narrowing of the spaces between the vertebrae, promoting curvature of the spine.
- Previous Trauma: Previous trauma, such as untreated spinal injuries or fractures, can lead to degenerative changes in the spine that contribute to degenerative scoliosis.
- Genetic Predisposition: Some individuals may have a genetic predisposition to develop degenerative changes in the spine that promote degenerative scoliosis.
- Already Existing Disorders: Pre-existing degenerative disorders such as spinal stenosis (narrowing of the spinal canal) or joint problems can predispose to degenerative scoliosis.
- Muscular Alterations: Changes in the strength or asymmetry of the muscles that support the spine can contribute to scoliotic curvature.
- Mechanical Factors: Mechanical factors such as postural imbalances, poor movement habits or excessive loads on the spine can influence the development of degenerative scoliosis.
It is important to note that degenerative scoliosis in adults differs from idiopathic scoliosis which often develops in adolescents with no apparent cause. SDA is often linked to age-related degenerative factors and structural changes in the spine.
Symptoms of Degenerative Scoliosis in Adults
- Lumbar Pain: Pain in the lumbar region (lower back) is one of the most common symptoms of degenerative scoliosis. This pain can be chronic and get worse over time.
- Radicular Pain: Some individuals may experience pain that radiates along compressed nerves, causing radicular symptoms such as tingling, numbness, or weakness in the lower extremities.
- Spine Stiffness: Degenerative scoliosis can cause stiffness in the spine, limiting mobility and making certain movements difficult.
- Posture Alterations: Scoliotic curvature of the spine can affect posture, leading to trunk tilt or visible asymmetries.
- Muscle Fatigue: Due to changes in the structure of the spine, the muscles that support the spine may become fatigued more quickly.
- Decreased Height: Degenerative scoliosis can cause loss of height due to compression of the intervertebral discs.
- Respiratory Difficulties (in severe cases): In some severe cases, the curvature of the spine can compress the lungs, causing difficulty breathing.
- Reflex Alterations: Changes in reflexes, particularly in the lower extremities, can sometimes be observed due to nerve compression.
It is important to note that symptoms of degenerative scoliosis can vary depending on the severity of the curvature, the presence of complications such as nerve compression, and individual pain tolerance. Some individuals may experience only mild or intermittent symptoms, while others may experience a significant deterioration in quality of life due to associated pain and stiffness.
Pathophysiology of degenerative Scoliosis in adults
Adult degenerative scoliosis (ADS) is a form of scoliosis that develops in adulthood due to degenerative changes in the spine. The pathophysiology of degenerative scoliosis in adults involves structural and degenerative changes that affect the spine. Here are the main aspects of the pathophysiology of DSA:
- Degeneration of Intervertebral Discs: Degeneration of intervertebral discs is a key element in the pathophysiology of DSA. With age, the discs lose their ability to absorb water, leading to a reduction in the height of the discs and a reduction in their cushioning function.
- Facet Osteoarthritis: The facet joints, located between the vertebrae, can suffer from degenerative osteoarthritis. This results in wear of the joint cartilage, inflammation and possible formation of osteophytes (bony growths).
- Osteophytes: Osteophyte formation can occur along the edges of the vertebrae and facet joints. These osteophytes may contribute to spinal curvature by adding a rotational component to the deformity.
- Disturbance of Sagittal Balance: Disc degeneration, facet osteoarthritis, and other degenerative changes can disrupt the sagittal balance of the spine, affecting posture and natural curvature.
- Loss of Disc Height: Reducing the height of the intervertebral discs contributes to the decrease in the distance between the vertebrae, which can lead to a lateral curvature of the spine, characteristic of scoliosis.
- Muscle Asymmetry: Degenerative changes can lead to muscle asymmetry, where certain muscle groups become stronger or weaker on one side of the spine, contributing to deformity.
- Compression of Nerves: The curvature of the spine in degenerative scoliosis can lead to compression of nerve roots, causing symptoms such as pain, tingling or numbness.
- Spinal Instability: Some patients may develop spinal instability due to degeneration of supporting structures, which can contribute to the progression of scoliosis.
Degenerative scoliosis in adults is often associated with factors such as aging, pre-existing degenerative disorders, previous trauma or genetic predisposition. Symptoms may vary depending on the severity of the deformity and the presence of complications such as nerve compression. Treatment of degenerative scoliosis in adults generally aims to relieve symptoms, prevent progression of the curvature, and improve spinal function. Management may include conservative approaches such as physiotherapy, medication and exercise, while in some severe cases surgery may be considered. Support is generally personalized based on the specific needs of each individual.
Radiographic signs of degenerative Scoliosis in adults
Radiographic signs of adult degenerative scoliosis (ADS) are assessed using x-ray images of the spine. These signs may include specific changes in the curvature and structure of the spine. Here are some of the radiographic signs commonly seen in SDA:
- Lateral Curvature of the Spine: Lateral curvature is one of the most obvious signs of degenerative scoliosis. On an x-ray of the spine, an abnormal lateral curvature may be seen.
- Vertebral Rotation: In addition to lateral curvature, SDA can cause rotation of the vertebrae, which can be detected on x-rays.
- Deformity of Intervertebral Discs: Changes in the structure of the intervertebral discs, such as dehydration and shrinkage, may be visible on x-rays.
- Osteophyte Formation: Osteophytes, or bony growths, can form along the edges of vertebrae in response to degeneration. These osteophytes are often visible on x-rays.
- Alterations in Normal Curvatures of the Spine: X-rays may reveal alterations in the normal curvatures of the spine, such as lumbar lordosis and thoracic kyphosis.
- Compression of Intervertebral Spaces: Compression of the spaces between the vertebrae can be detected on x-rays, indicating a loss of disc height.
- Facet Osteoarthritis: Signs of osteoarthritis in the facet joints, such as joint enlargement or deformity, may be visible.
- Enlarged Intervertebral Foramina: The intervertebral foramens, which are the openings through which nerve roots exit the spine, may show enlargement or deformity.
- Vertebral Displacement: In some cases, signs of vertebral displacement or subluxation may be seen on x-rays.
