The spinal cord starts at the base of the skull and ends in the lower thoracic or upper lumbar area of the spine. At each level of the spine, nerves leave the spinal cord to innervate parts of the body. In the cervical spine, or neck area, these nerves provide sensation and movement to the arms. In the thoracic area which contains your ribs, the nerves innervate some of the accessory muscles for respiration and provide sensation to your chest wall. In the lumbar spine, or lower back the spinal cord ends as it enters the area and is called the ‘cause equina.’ This is where all the nerves that will innervate the legs start. These nerves will travel in the lumbar spine and then exit the spine to travel in the legs. These nerves obviously supply neural input and output to the legs and lower half of the body.
The spinal cord functions as a multidirectional pathway to bring signals from your brain to your body and sensory input from your body back to your brain. This pathway is used to create the complex movements, reflexes and sensations of the body. Interruption of the spinal cord and this pathway can be caused by things such as trauma, tumors, neurodegenerative diseases such as multiple sclerosis (MS), and degenerative changes. Degenerative changes are age related and ‘wear and tear’ changes that occur in the spine joints, bones, disks and ligaments.
The most common causes of spinal cord dysfunction is due to degenerative changes that cause spinal stenosis. Spinal stenosis is the term used when the bony canal that the spinal cord and nerves travel through has become too narrow. If the narrowing, or stenosis, occurs in the cervical or thoracic spine compression of the spinal cord may occur. It is important to note that degenerative changes occur in the spine, and the rest of the body, as normal part of the aging process. Most of the time these changes do not cause problems. However, in some individuals severe changes occur in the spine to the extent that the spinal cord becomes compressed.
Remember that the spinal cord is critical for relaying information between the body and brain. Dysfunction, which can occur if there is compression of the spinal cord, will result in impaired communication between the brain and body. The most common site of spinal cord compression from degenerative changes occurs in the cervical spine or neck. The most common symptoms include sensory symptoms such as numbness and tingling in the arms and hands. A patient may experience pain in the arms, often described as aching or electric shock type pain. Weakness may occur, especially in the hands and patients have a difficult time using their hands. Loss of coordination may occur which results in poor balance and frequently dropping objects. Because the brain cannot regulate the bodies natural reflexes normally, patients with cord compression may have exaggerated reflexes when tested on physical exam. The medical term used for patients with spinal cord dysfunction is ‘myelopathy.’ The severity of symptoms often depends on the amount of spinal cord compression and length of symptoms.
Degenerative changes in the thoracic spine are generally less severe because the ribs provide additional support and limit the movement in the thoracic spine. Therefore, there is less ‘wear and tear’ (degenerative changes) in the thoracic spine and decreased incidence of degenerative spinal stenosis. Degenerative changes are common in the lumbar spine, especially the lower lumbar spine. However, since the spinal cord usually ends at the beginning of the lumbar spine you do not commonly see spinal cord compression in the lumbar spine either. Stenosis in the lumbar spine usually results in nerve compression rather than spinal cord compression. Although these can present with similar symptoms there are important differences in terms of treatment, prognosis, and physical exam findings which we will cover in a future blog.
Treatment of spinal cord compression is decompression. This means opening the spinal canal so the spinal cord is free from any compressive lesions. In degenerative stenosis the spinal canal is usually narrowed from a combination of bone spurs, overgrown ligament and sometimes disk material. Surgery is performed to remove the bone, ligament and disk that is causing compression of the spinal cord. Again, it is important to remember that most degenerative changes including bone spurs or degenerated discs do not cause problems or require surgery because the do not cause compression of the spinal cord.
Unfortunately, the surgery does not repair the actual spinal cord. Surgery can remove the compression which often allows for the spinal cord to heal and symptoms to improve. However, recovery will vary depending on amount of compression, cause, severity, length of symptoms, a person’s age and overall health. This is why it is important to see your physician if you experience symptoms of spinal cord compression and catch it early to provide the best chance of improvement. There are also other reasons one can experience similar symptoms to cord compression such as pain and numbness in the arms or hands. Examples include peripheral neuropathy and carpal tunnel syndrome. Your physician will best be able to determine the exact cause using physical exam, history and ancillary tests such as MRIs, nerve conduction studies and CTs.
If you have any of these symptoms contact our office and our experts will help diagnose, inform and develop a treatment plan that is right for you!