A spinal lesion is any area of abnormal or damaged tissue in or around the spinal cord. The term is broad on purpose: it covers everything from a small patch of inflammation caused by multiple sclerosis to a tumor pressing on the cord to damage from a car accident. What all spinal lesions share is the potential to interrupt the signals your spinal cord carries between your brain and the rest of your body.
Your spinal cord contains two main types of nerve pathways. Motor tracts carry signals from your brain to your muscles, telling them when and how to move. Sensory tracts carry information in the other direction, relaying temperature, pressure, pain, and the position of your limbs back to your brain. When a lesion damages or compresses these pathways, it can impair muscles and nerves anywhere below the affected level.
Where Spinal Lesions Form
Doctors classify spinal lesions partly by their physical location relative to the spinal cord and the protective membrane (called the dura) that surrounds it. This distinction matters because it narrows down the likely cause and shapes treatment decisions.
- Inside the cord itself. These are called intramedullary lesions. They grow within the nerve tissue of the spinal cord. MS plaques and certain rare tumors fall into this category.
- Outside the cord but inside the membrane. These develop in the space between the spinal cord and the dura. They often arise from the nerve roots or the cord’s lining.
- Outside the membrane entirely. These sit in the surrounding bone, discs, or soft tissue and press inward on the cord. Metastatic cancer and herniated discs are common examples.
Lesions can also occur at any level of the spine, from the neck (cervical) down through the mid-back (thoracic) and lower back (lumbar). The higher up a lesion sits, the more of the body it can potentially affect, because signals to everything below it must pass through that point.
Common Causes
Spinal lesions aren’t a single disease. They’re a finding that can result from very different processes.
Trauma is among the most common causes. Motor vehicle accidents and serious falls account for the majority of spinal cord injuries in the United States, followed by acts of violence (primarily gunshot wounds), sports injuries, and workplace accidents.
Tumors are another major category. Primary spinal tumors, those that originate in the spine itself, are relatively rare and often benign. Far more common are metastatic tumors, cancers that started somewhere else in the body and spread to the spine. Between 30 and 70 percent of cancer patients develop metastatic spine disease during the course of their illness, according to Johns Hopkins Medicine.
Inflammatory and autoimmune diseases can produce lesions directly within the cord’s nerve tissue. Multiple sclerosis is the most well-known example. In MS, the immune system attacks the insulating coating around nerve fibers, leaving characteristic lesions that show up on MRI. The spinal cord is one of five key regions doctors evaluate when diagnosing MS. In some forms of the disease, finding two or more spinal cord lesions is enough to confirm that damage has spread to multiple areas of the nervous system, even without brain lesions.
Vascular problems can also cause spinal lesions. A disruption in blood flow to the cord, whether from a blood vessel abnormality, a clot, or bleeding, can damage tissue quickly. Degenerative conditions like herniated discs or spinal stenosis create lesions by physically compressing the cord or nerve roots over time.
Symptoms Depend on Location and Size
A spinal lesion’s effects are determined almost entirely by where it is and how much of the cord it involves. A small lesion on one side of the cord might cause weakness in one leg. A larger lesion higher up in the neck could affect all four limbs.
Motor symptoms include weakness, reduced coordination, muscle stiffness or spasms, and in severe cases, paralysis below the level of the lesion. Sensory symptoms can range from numbness and tingling to a loss of the ability to feel temperature, pressure, or pain. Some people describe a band-like tightness around the torso at the level of the lesion.
Autonomic functions, the body’s background operations, are also vulnerable. Bladder and bowel control can be disrupted because the nerves that coordinate those functions run through the spinal cord. Changes in blood pressure regulation and sexual function are also possible, depending on the lesion’s location.
Not all spinal lesions cause symptoms. Small inflammatory lesions from MS, for instance, are sometimes discovered incidentally on an MRI done for another reason. These “clinically silent” lesions still matter diagnostically, but the person may feel perfectly fine.
How Spinal Lesions Are Detected
MRI is the reference standard for evaluating spinal lesions. It provides detailed images of the soft tissue inside and around the spinal cord without radiation exposure. Specific MRI sequences are chosen to maximize contrast between the spinal cord, the fluid surrounding it, and any abnormal tissue. This allows radiologists to see whether the cord is being compressed, whether there is swelling inside the cord, and how much of the spinal canal is affected.
In emergency settings, such as after trauma, a streamlined MRI protocol can quickly identify cord compression. If an initial scan raises concerns about a particular area, additional cross-sectional images are added to get a closer look. CT scans and X-rays play a supporting role, particularly for evaluating bony structures, fractures, or calcifications that MRI may not characterize as well.
When the cause isn’t obvious from imaging alone, doctors may order blood tests, a lumbar puncture to analyze spinal fluid, or a biopsy of the lesion itself. For suspected MS, spinal fluid analysis can reveal specific immune markers that support the diagnosis.
Treatment Varies by Cause
There is no single treatment for spinal lesions because the underlying cause dictates the approach.
For inflammatory lesions like those from MS, treatment typically focuses on calming the immune response. High-dose anti-inflammatory steroids are often used during acute flare-ups to reduce swelling around the cord and limit further damage. Long-term management involves medications that modify immune system activity to prevent new lesions from forming.
Tumors compressing the spinal cord often require a combination of surgery and radiation. In metastatic spine cancer, the goal is usually to relieve pressure on the cord, stabilize the spine, and preserve as much neurological function as possible. Steroids are frequently given before surgery to reduce swelling, though longer courses of steroids before the operation have not been shown to consistently improve neurological outcomes.
Traumatic spinal cord injuries may need emergency surgery to stabilize the spine, remove bone fragments, or relieve compression. Recovery afterward depends heavily on the severity and completeness of the injury. Rehabilitation, including physical and occupational therapy, is a central part of the process for both traumatic and non-traumatic spinal lesions.
For degenerative causes like herniated discs or spinal stenosis, treatment often starts conservatively with physical therapy and pain management. Surgery becomes an option when compression is worsening or neurological symptoms are progressing.
What the Outlook Depends On
The prognosis for a spinal lesion hinges on what caused it, how quickly it was identified, and how much damage the cord sustained before treatment began. Inflammatory lesions caught early in a disease like MS can often be managed effectively, with many people maintaining good function for years. Metastatic tumors involving the spine carry a more complex outlook that depends on the type and stage of the underlying cancer.
One consistent finding across causes is that the speed of treatment matters. Spinal cord tissue does not regenerate easily. Compression or inflammation that persists for hours or days can cause permanent damage that would have been preventable with earlier intervention. New or worsening weakness, numbness below a certain level of the body, or sudden changes in bladder or bowel control are signs that the spinal cord may be under acute threat.