Nerve Root Injections
The nerve root is the part of the nerve that branches out from the spinal cord on its way to the outer parts of the body. They are found all along the length of the spinal cord and must negotiate the spinal column, vertebrae, intervertebral discs, facet joints and the surrounding ligaments and muscles on the way to their destination. Sometimes, these nerve roots can become damaged or irritated because an element of the spine has degenerated or been injured. When this happens, not only can one experience pain at the point of the nerve root, but also in the area that the nerve controls, such as the leg or arm. In this case, a nerve root injection can be an effective treatment and relieve the pain.
What Can go Wrong?
There are a number of ways that nerve roots can be negatively affected. The most common is a prolapsed intervertebral disc, or what we call a slipped disc. This can happen because of a strain, such as lifting something too heavy, or because of normal wear and tear. As we age, the intervertebral disc, which is made up of a tough fibrous outer core and a soft centre, can break down, causing the soft centre to bulge out between fibres of the outer core. If the soft centre bulges out enough, it can put pressure on nearby nerve roots. The intervertebral disc can also loose liquid with age, so that it ceases to be an effective cushion between vertebrae. This can result with less space between the vertebrae and can put pressure on the nerve roots.
When this happens to the sciatic nerve, which is the largest nerve in the body, originates in the lower back, or lumbar, region, and controls the legs, this is called sciatica. This is probably the most common form of nerve root damage, although it can happen to any nerve branching out from the spine from the neck down to the pelvis.
A nerve root injection is typically performed in an out-patient centre and the majority of patients will be able to go home the same day. First, the patient is given an IV, through which he is administered a mild sedative. The patient is positioned on his stomach and a needle is guided by fluoroscopy, or a live x-ray, to a position close to the affected nerve root. A local anaesthetic, sometimes combined with an anti-inflammatory steroid, is injected, which bathes the nerve root. The anaesthetic works to block the pain signals from being sent to the brain, while the steroid works to ease the inflammation of the nerve or the tissues around the nerve which are causing the problem. This procedure generally takes less than twenty minutes to perform.
Patients are generally watched in an observation ward for an hour before going home. They should have someone available to drive them home and stay with them the night of the procedure. Most patients will feel relief immediately after the procedure, although many will experience discomfort where the injection was done for a day or two.