Spinal anatomy is a remarkable combination of strong bones, flexible ligaments and tendons, large muscles and highly sensitive nerves. It is designed to be incredibly strong, protecting the highly sensitive nerve roots, yet highly flexible, providing for mobility on many different planes. Most of us take this juxtaposition of strength, structure and flexibility for granted in our everyday lives - until something goes wrong. Once we have back pain, we're driven to know what's wrong and what it will take to relieve the pain and prevent a recurrence.
Origin of Pain
The lumbar spine refers to the lower back, where the spine curves inward toward the abdomen. It starts about five or six inches below the shoulder blades, and connects with the thoracic spine at the top and extends downward to the sacral spine. A joint is where two or more bones are joined. Joints allow motion (articulation). The joints in the spine are commonly called Facet Joints. Other names for these joints are Zygapophyseal or Apophyseal Joints. Each vertebra has two sets of facet joints. One pair faces upward (superior articular facet) and one downward (inferior articular facet).
Producing Back Pain
There is one joint on each side (right and left). Facet joints are hinge–like and link vertebrae together. They are located at the back of the spine (posterior).Facet joints are synovial joints. This means each joint is surrounded by a capsule of connective tissue and produces a fluid to nourish and lubricate the joint. The joint surfaces are coated with cartilage allowing joints to move or glide smoothly (articulate) against each other. These joints allow flexion (bend forward), extension (bend backward), and twisting motion. Certain types of movement are restricted. The spine is made more stable due to the interlocking nature to adjacent vertebrae.
Causes of Back Pain
Many different structures in the spine can cause back pain, potentially when:
The large nerve roots that go to the legs and arms are irritated
The smaller nerves that innervate the spine are irritated
The large paired back muscles (erector spinae) are strained
The bones, ligaments or joints themselves are injured
The disc space itself is a source of pain
Therefore, a review of spinal anatomy is important to understand the causes of back pain, neck pain, and sciatica (leg pain), and evaluate treatment options.
Applications For Lumbar Facet Pain Control
What is a medial branch nerve?
The medial branch is the branch of the spinal nerve that carries sensation and pain signals from the facet joint back to the spinal cord.
What are the indications for a facet joint injection or medial branch block?
These injections are performed as a diagnostic test when it is thought that a facet joint or joints is part of the process that is causing the pain. A small amount of a local anesthetic is injected into the joint or over the medial branch nerve to see if this will temporarily relieve your back pain.
How long will the pain relief last after a facet joint injection or medial branch block?
The local anesthestic block will only last a few hours. A small amount of steroid may be injected along with the local anesthetic and may provide pain relief from days to months.
How do the facet joints cause pain?
The facet joints are just like any other joint in the body, they are succeptable to acute injury (sprain or strain) as well as degenerative arthritis. In the back, the facet joints may cause low back pain, hip and buttock pain, and leg pain. The pain is especially bad when leaning backwards or twisting your spine. The pain also tends to be worst first thing in the morning and in the evening.
What if a facet joint injection does not improve my pain?
Facet joint injections or medial branch blocks are performed to diagnose pain being caused by the facet joints in your back and will not relieve pain caused by intervertebral discs, spinal nerves, or muscles, which can continue to cause pain after the procedure. If your pain is not relieved after the procedure, the facet joints have been ruled out as the source of your pain.
What if the facet joint injection is successful?
If the facet joint injection successfully treat your pain for a significant period of time, they may be repeated as necessary. If the facet joint injection relieves your pain for a short period of time, then you will likely be scheduled for radiofrequency ablation (RFA) of the medial branch nerves.
Are there any restrictions following the facet joint injection?