Spinal stenosis occurs when spaces within your backbone narrow, putting pressure on the spinal cord and nerves. This compression can lead to nerve damage.
What is Spinal Stenosis?
Spinal stenosis involves the constriction of space around the spinal cord or the nerve roots that exit the spine. This narrowing can occur in the central spinal canal, which houses the spinal cord, or in the neural foramen, the small openings through which individual nerve roots pass. It most frequently affects the lower back (lumbar spinal stenosis) and the neck (cervical spinal stenosis).
Age-related degeneration, often linked to osteoarthritis, is the most common cause. As people age, cartilage cushioning spinal joints can wear down, leading to bone spurs that protrude into the spinal canal or foraminal openings, reducing space for nerves.
Other factors also contribute to this narrowing. Ligaments, which hold spinal bones together, can thicken and bulge into the spinal canal. Intervertebral discs, acting as shock absorbers, can dry out and weaken with age, making them prone to bulging or herniating and pressing on nerves.
How Spinal Stenosis Causes Nerve Damage
Spinal stenosis causes nerve damage through direct compression of the spinal cord or individual nerve roots. As space within the spinal canal or nerve root exits shrinks, it physically squeezes these delicate neural structures, disrupting normal nerve signal transmission.
Compression can also reduce blood supply to affected nerves, a condition called ischemia. Nerves require oxygen and nutrients; diminished supply damages or kills nerve cells, impairing function.
Mechanical irritation from compression and reduced blood flow can trigger inflammation around the nerves. This inflammatory response causes swelling and releases chemicals that harm nerve tissue. The combination of pressure, ischemia, and inflammation contributes to neurological dysfunction.
Spinal cord compression, especially in the neck, can lead to myelopathy, affecting motor and sensory functions below the compression point. Individual nerve root compression results in radiculopathy, with symptoms localized to that nerve’s area. Severe lower back compression of the cauda equina nerve bundle can cause cauda equina syndrome, a medical emergency.
Recognizing Symptoms of Nerve Compression
Symptoms of nerve compression from spinal stenosis vary based on location and severity. Sensory symptoms include radiating pain, such as sciatica from lower back compression, which causes burning or aching pain down the leg.
Patients may also experience tingling (“pins and needles”), numbness, or a burning sensation in the arms, hands, legs, or feet. These sensory disturbances occur because compressed nerves cannot transmit signals accurately to the brain.
Motor symptoms, indicating impaired muscle control, can also develop. These include muscle weakness in affected limbs, making walking or lifting difficult. Some individuals may experience loss of balance or coordination, increasing fall risk. In severe cases, foot drop can occur, making it difficult to lift the front part of the foot.
Symptoms often worsen with activities that extend the spine, like prolonged standing or walking, and may improve with leaning forward or sitting. This positional relief is a characteristic feature of neurogenic claudication, common in lumbar spinal stenosis. The symptom pattern helps healthcare professionals determine which nerves are affected.
Importance of Early Intervention for Nerve Damage
Addressing nerve compression from spinal stenosis without delay is important to prevent permanent neurological deficits. Prolonged pressure on the spinal cord or nerve roots can cause irreversible damage, meaning nerve function may not fully recover even after compression is relieved. This underscores the need for prompt evaluation.
The goal of intervention is to alleviate pressure on compromised nerves, stopping further deterioration and aiming to restore function. Timely diagnosis and management are important to prevent long-term complications like chronic pain, persistent weakness, or permanent loss of sensation or motor control.
Seek medical attention for persistent pain, numbness, tingling, or muscle weakness suggesting nerve involvement. “Red flag” symptoms warrant immediate medical evaluation, such as sudden severe leg weakness or new bladder/bowel dysfunction. These signs could indicate severe compression, like cauda equina syndrome, requiring urgent treatment to avoid irreversible damage.