The conus medullaris is the bundled, tapered end of the spinal cord nerves. Situated near the first two lumbar vertebrae, the conus medullaris ends at the cauda equina, a bundle of spinal nerves and nerve roots. Consequently, problems with the conus medullaris often affect the cauda equina. Conus medullaris syndrome is a secondary form of spinal cord damage resulting from injuries to the lumber vertebrae.

What is Conus Medullaris Syndrome?

Conus medullaris syndrome is a type of incomplete spinal cord injury that is less likely to cause paralysis than many other types of spinal cord injuries. Instead, the most common symptoms include:

    • Severe back pain
    • Strange or jarring sensations in the back, such as buzzing, tingling, or numbness
    • Bowel and bladder dysfunction, such as difficulty controlling your elimination functions
    • Sexual dysfunction
    • Weakness, numbness, or tingling in your lower limbs
    • Sensations in your lower limbs that aren't caused by a clinical issue. For instance, you might have itchiness in your leg that is not well-explained by an allergic reaction or other issue.

 

What Causes Conus Medullaris Syndrome?

Conus medullaris syndrome isn't a disease in its own right, but rather the product of a spinal trauma. In most cases, a blow to the back—such as from a car accident or gunshot—is to blame. But some diseases, notably spinal cord infections, malformations of the spinal column due to spinal stenosis, and spinal tumors can also cause the syndrome.

Conus medullaris syndrome manifest symptoms that are similar to cauda equina syndrome, but the two conditions require different treatment. Conus medullaris typically produces sudden symptoms on both sides of the body, while cauda equina syndrome usually develops over time, producing uneven symptoms concentrated on one side of the body.

Some other criteria that can help you and your care team differentiate one from the other include:

    • Cauda equina typically causes severe pain, while conus medullaris results in mild to moderate pain, if any pain at all is present.
    • Conus medullaris can be caused by an injury, lesion, or infection, while cauda equina is almost always caused by a lesion or infection.
    • Cauda equina may eliminate the patellar and Achilles reflexes, while conus medullaris typically only interferes with the Achilles reflex.
    • Conus medullaris is more likely than cauda equina to result in pain concentrated in the lower back.
    • Impotence is more common with conus medullaris than cauda equina.

Treatment for Conus Medullaris Syndrome

To diagnose you with conus medullaris syndrome, your doctor may conduct MRI imaging of your lower back and spine. Treatment varies, and depends on the cause of the injury as well as its extent.

Spinal decompression surgery often helps, and if a physical impediment to function remains—such as a tumor or the remnants of a bullet—your doctor may remove these to restore spinal function. Radiation may help if your symptoms are due to cancer. And if an infection caused the symptoms, or your injury is so severe it led to an infection, you may need intravenous or oral antibiotics. You will likely also need physical therapy to regain function.

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