DISC ISSUES EXPLAINED
There are many causes that lead to spinal arthritis and an unhealthy or injured disc. Due to the fact that there is very little or no nerve supply to discs, when you initially injure them, you literally don’t feel it. Only when the disc pushes out and touches a spinal nerve or the spinal cord itself, do you actually feel disc pain or have other associated symptoms. There is some evidence that discs themselves may generate pain signals, but it is not as common and is not well understood.
The most common scenario of disc issues, starts many years before you feel it. Genetic predisposition to the vertebra to slow or stop supplying proper nutrients to the disc is a common factor. Injuries as a child or young adult that were completely ignored are highly likely to be the start of these disc problems. I spend some time going back in time with patients going over likely injuries, many times 20 years back, that are the root start or cause of their current disc or spinal arthritis pain. These injuries again are not felt initially, but insidiously discs undergo gradual changes, compress, and dehydrate until the disc pushes out and finally hits the exiting nerve root from the spine or the spinal cord. This pressure on the nerve is actually what causes the pain you feel either locally or running down your back, arm, or leg. Patients often think that it was something that they just did to start their pain, but again it has been most times, brewing for many years. There are cases where an injury happens and a perfectly healthy disc ruptures abruptly and causes immediate nerve compression and severe pain.
As a disc is compressed, and is bulged out, like a squished jelly donut, the edges that are protruding begin to get ossified or calcified by the body. This could be an attempt by the body to stop the protrusion from getting worse. These calcifications show up on an x-ray as bones spurs and sharpening of the edges of the vertebra. These are known as osteophytes. This is the most common sign of osteoarthritis of the spine that patients can easily see.
When a disc finally contacts an exiting nerve root from the spinal cord, where ever that nerve leads to, is where you feel like you have pain. There are 2 main types of nerves that you feel and 2 types of nerves that you don’t “feel”. Sensory and motor nerves will give you a symptom of sharp pain, burning, tingling, numbness, spasm, deep aching, and other types of sensations. Sympathetic and parasympathetic along with other nerves that feed organs will not elicit pain, but will alter the way the brain talks to the organ and the way the organ talks to the brain. Cord compression is likely to give you symptoms of clumsiness about your hands, arms, feet, or legs. Severe lower back disc issues for instance can cause urinary and intestinal issues such as incontinence. These issues should be considered to be more of an emergency situation as it means severe compression is happening at the spinal cord level.
The most common things that we see in our office is a radiating pain into the upper back (shoulder blade), upper shoulder, arm, and/or fingers when a disc is pinching a nerve in the neck. Lower back discs most commonly cause lower back pain that radiates through the buttocks, back of the leg, outside of the calve, and portions of the feet. When compression of a nerve is severe, muscles start to get weak and you may begin to drop things or drag your foot. These are considered severe issues and need to be addressed sooner than later.
Below is an image of 2 discs excised from a human cadaver. The one on the left is a normal sized health disc, while the right is a long-term degenerative disc. Notice how the disc tissue has flattened and hardened especially along the edges as the body began to attempt to stop the progression and added dense substances like calcium to stabilize the damaged disc.