Osteoarthritis of the spine, also known as spondylarthrosis or spondylosis, is a degenerative disease that leads to degeneration and loss of function of the spine.
Although aging is the primary cause of spinal osteoarthritis, there can be wide individual variation in location and severity. The degenerative processes of spondylosis can affect the cervical ( neck ) , thoracic (mid-back), or lumbar (lower back) regions of the spine .
A technical term provides information about which section is affected by osteoarthritis:
- In the neck area one speaks of cervical spondylosis.
- In the lumbar region it is called lumbar spondylosis.
- Mid-back thoracic spondylosis.
Spondylosis does not only refer to spinal arthrosis, it is rather a collective term for all degenerative diseases of the spine.
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Anatomical changes in the spine
With age, certain biochemical changes occur in tissues throughout the body.
The structure of the intervertebral discs (anulus fibrosus, lamellae, nucleus pulposus) on the spine can be impaired.
The fibrocartilage ring (anulus fibrosus) consists of 60 or more concentric bands of collagen fibers called lamellae.
The gelatinous core (nucleus pulposus) is a gel-like substance inside the intervertebral disc and is surrounded by the fibrous ring. The core consists of collagen fibers, water and proteoglycans.
The degenerative effects of aging can weaken the fibrocartilage ring or its structure, causing wear and tear and the formation of small tears. The core’s water content decreases with age, affecting its ability as a shock absorber to absorb daily trauma and micro-trauma. Due to the structural changes caused by degeneration, the height of the intervertebral disc is reduced and the risk of a herniated disc increases.
The facet joints are also known as the zygaphyseal joints. Each vertebral body has four facet joints that function like hinges.
These are the mobile joints of the spine that allow for extension, flexion, and rotation.
As with other joints, the bony joint surfaces are covered with cartilage.
Cartilage is a special type of connective tissue that provides a self-lubricating and low-friction sliding surface.
Facet joint osteoarthritis leads to loss of cartilage and formation of osteophytes (bone spurs). These changes can lead to hypertrophy of the joints and spondylosis, known as degenerative joint disease.
The bone spurs (osteophytes) can form along the vertebral plate (upper part of the vertebral body). These bony outgrowths (exostosis) can impair the blood supply to the vertebra. Bone sclerosis, which is the thickening or hardening of the bone beneath the articular surface, also occurs.
Ligaments are fibrous strands of connective tissue that connect the structures of the spine (such as the vertebrae) and protect them from excessive movement (such as hyperextension).
The degenerative changes can result in loss of ligament strength.
The yellow vertebral ligament (ligamentum flavum) can thicken and obstruct the back of the dura mater (a membrane of the spinal cord).
Spondylosis, causes and risk factors
There are various reasons that make some people particularly susceptible to osteoarthritis. However, like almost all deforming diseases that can affect the organism, it is likely to be caused by a combination of different risk factors occurring together.
Repeated trauma to the spine, such as strains and compressions resulting from traffic accidents , surgery, sports injuries, poor posture , and work-related activities can cause spinal arthrosis.
Athletes and people who perform repetitive and physically demanding movements are most at risk. Other risk factors for developing spinal arthrosis:
- The normal and advanced aging process of the spinal structures begins from the age of 30 and is often job-related.
- Gender: Osteoarthritis mainly affects women after menopause, but up to the age of 45 it is mostly men who are affected.
- Obesity: Obesity puts stress on the weight-bearing joints and spine, especially in middle-aged people.
- Heredity: Individuals who have close relatives with osteoarthritis, congenital joint defects, spinal misalignment, or leg misalignment will be more likely to develop spondylosis.
When osteoarthritis occurs for no apparent reason, as is usually the case, it is called primary osteoarthritis and appears to be mainly related to the aging process.
Aging leads to changes in cartilage and synovial fluid, the water content in the tissue increases and the protein content decreases.
Signs and Symptoms of Spondylosis
Even if the X-ray shows a clear spondylosis, many patients do not have any symptoms.
For example, lumbar spondylosis (lower back osteoarthritis) is asymptomatic in 27-37% of people.
Spondylosis can cause back pain and neck pain when a nerve is compressed (nerve root irritation).
Compression of the nerves is caused by bony prominences or bony spurs at the facet joints, resulting in narrowing of the nerve exit foramen (see Figure: Intervertebral Foral Stenosis ).
Even if disc bulging is not severe enough to directly impinge on a nerve, it can cause localized inflammation and irritation of the nerves that run through the spine. A herniated disc
can also press against the ligaments of the spine and cause pain.
The pain can cause the spinal area to try to lock itself, which can lead to localized stiffness, muscle spasms, and activation of trigger points.
There is conflicting opinion as to whether mild spondylosis, small bone spurs, and disc bulging without pinching nerves can cause back pain. Most middle-aged and elderly people show signs of spondylosis on X-ray but do not feel pain. Therefore, other factors are probably responsible for back pain.
Symptoms of spondylosis include pain in the area where the signs of osteoarthritis are located, primarily the lower back (lumbar spine) and neck.
If a nerve is pinched by a herniated disc, the pain can radiate into the limbs.
For example, a significant herniated disc in the lumbar spine could pinch the sciatic nerve and cause pain that originates in the lower back and travels down the leg to the feet. This pain is known as sciatica or sciatica. Back pain caused by bulging or protrusion of the disc worsens with prolonged standing, sitting, and bending over, and decreases with frequent changes of position and walking.
Back pain that occurs as a result of facet joint osteoarthritis worsens with standing and walking, and decreases with sitting, lying, and bending forward.
A feeling of numbness and pins and needles may occur when a nerve is irritated. If nerve irritation is severe, the affected limb may show weakness and lose some of its sensitivity.
If an intervertebral disc presses against the spinal cord, nerve function can be impaired (myelopathy).
The symptoms of myelopathy are: numbness, tingling, weakness. A serious herniated disc in the cervical spine that extends into the spinal cord can cause numbness, tingling , and weakness in the arms and even the legs.
