The spine is a flexible column composed of bones, called vertebrae, interspersed with shock-absorbing discs made of cartilage. These discs can be damaged by trauma or by the effects of wear and tear over time. When the tough outer rings of the discs become so worn that they rupture, the gelatinous center of the disc, called the nucleus pulposus, can bulge outward and put pressure on the spinal nerves. Steroids are sometimes used to treat the symptoms that result.
Wet Tap
Sometimes low back disc protrusion is treated via injection of the steroids into the epidural space, which is the space that lies outside the spinal cord and is surrounding membrane, and inside the central channel of the vertebral column through which the spinal cord descends, which is called the spinal canal.
When the needle used to inject the steroid punctures the membrane around the spinal cord, called the dura mater, the patient may experience headaches that last for several days. This condition is known as dural puncture, or "wet tap." Dr. Richard Staehler , a physiatrist with NeuroSpine Center of Wisconsin, states that sometimes an additional injection, called a blood patch, is necessary to plug the puncture site and end the headache.
Nerve Damage
Nerve damage is a rare but worrisome complication that sometimes arises as a result of steroid injections. Nerve damage can occur when the needle penetrates the dura and into one of the spinal nerves.
The spinal column has 31 sets of nerves that exit the spinal cord through openings in the vertebral column called foramina. Five of those sets are lumbar nerves. Staehler adds that infection and bleeding, which sometimes accompany epidural injection, can also cause nerve damage.
Loss of Bone Density
Long-term steroid use, whether they are injected or taken orally, is known to have a negative effect on bone formation. The New Zealand Dermatological Society states that up to 50 percent of those who take corticosteroids orally will experience bone thinning and subsequent fractures.
Even minimal incidents of trauma can cause spinal fractures in those who experience osteoporosis due to corticosteroid use. Concerns over the osteoporotic effects of steroid use have prompted recommendations that patients be monitored via bone scans to measure bone density, and that the use of calcium and vitamin D supplements, female hormone replacement tablets and bisphosphonates be used to help combat the steroid’s bone-thinning effects.
