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 lumbar vertebrae.
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:
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:
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.
Additional resources for further reading on this subject: