Neuropathy is a condition where damage to the peripheral nerves results in symptoms like weakness, pain, and altered sensation, such as numbness or tingling. While many causes exist, spinal structures can compress or irritate the nerve roots exiting the spinal cord, creating a specific type of neuropathy known as radiculopathy. This mechanism causes symptoms that often radiate far from the back, traveling down the arms or legs.
The Spinal Mechanism of Nerve Damage
The spinal column consists of bones (vertebrae) cushioned by intervertebral discs. Nerves branch out from the spinal cord, passing through small openings between the vertebrae called neural foramen. These nerve roots are particularly vulnerable to compression as they exit.
Compression occurs when surrounding structures narrow this exit space or press directly against the nerve root. Physical displacement of a disc or bone can mechanically pinch the nerve, immediately disrupting electrical signals and initiating inflammation.
Beyond mechanical pressure, “chemical radiculitis” also contributes to nerve damage. When an intervertebral disc is damaged, it can release inflammatory chemicals and neuropeptides onto the adjacent nerve root. These substances create chronic irritation and hyperalgesia, making the nerve overly sensitive to even minor stimuli.
Specific Spinal Conditions That Cause Neuropathy
Several degenerative and traumatic conditions in the spine directly lead to nerve root compression.
A common cause is a herniated disc, which occurs when the soft, gel-like center of an intervertebral disc pushes through a tear in the outer layer. This displaced material presses directly on the spinal nerve root, causing pain and dysfunction that radiates along the nerve’s path.
Another frequent cause is spinal stenosis, a structural narrowing of the spinal canal or the neural foramen. This narrowing often results from age-related changes, such as the thickening of ligaments or the formation of bone spurs (osteophytes). As these tissues encroach, they reduce the available room for the spinal cord and nerve roots, leading to chronic compression.
Spondylolisthesis is a condition where one vertebra slips forward over the one beneath it. This misalignment alters the spinal column anatomy, pinching or stretching the nerve roots as they pass through the misaligned foramen.
How Spine-Related Neuropathy Presents
Symptoms of radiculopathy travel away from the spine and into an extremity. In the lower back, this is lumbar radiculopathy, commonly known as sciatica, where discomfort travels down the buttocks and leg. When the issue is in the neck, it is cervical radiculopathy, manifesting as pain, numbness, or tingling that extends into the shoulder, arm, or hand.
The presentation is categorized into sensory and motor symptoms. Sensory issues include sharp, shooting, or burning pain, along with tingling, prickling, or numbness (paresthesia). These symptoms follow a predictable dermatomal pattern, corresponding to the specific area of skin supplied by the compressed nerve root.
Motor symptoms involve the muscles controlled by the affected nerve root, leading to muscle weakness or a loss of reflexes. Severe weakness can result in functional impairments, such as “foot drop” in the lower extremity.
Diagnosis and Management Options
Diagnosing spine-related neuropathy begins with a thorough physical examination, where a physician tests muscle strength, reflexes, and sensation patterns. This clinical assessment helps localize the affected nerve root and determines if symptoms align with a radicular pattern.
Imaging studies visualize the structural changes causing compression. Magnetic Resonance Imaging (MRI) or Computed Tomography (CT) scans show soft tissues (like herniated discs) and bony abnormalities (like spinal stenosis or bone spurs). To confirm the functional impact, nerve tests like electromyography (EMG) and nerve conduction studies (NCS) assess the electrical activity of the nerves and muscles, quantifying the degree of nerve damage.
Management typically begins with conservative treatments aimed at relieving pressure and inflammation. These options include physical therapy to strengthen supporting muscles and improve posture, along with non-steroidal anti-inflammatory drugs (NSAIDs) to reduce swelling. Epidural steroid injections can also deliver a potent anti-inflammatory agent directly to the site of the irritated nerve root. If conservative management fails, surgical intervention may be considered to physically decompress the nerve.