Lumbar facet joint are small pairs of joints on the back side of the spine where the vertebrae meet. These joints provide stability to the spine by interlocking two adjacent vertebrae. Facet joints also allow the spine to bend forward (flexion), bend backward (extension), and twist.
Inflammation of facet joints can occur from injuries or from arthritis. Many times, particularly in the case of injuries, one may not see abnormalities on an x-ray or MRI.
The term lumbar stenosis refers to any narrowing of the spinal canal. There are many causes of spinal stenosis; the most common is degeneration of the spine, which occurs almost inevitably as a part of the aging process.
Several factors contribute to the narrowing of the spinal canal with degenerative changes. First, wear and tear causes the facet joint to enlarge into the spinal canal. Second, the major ligament of the spinal canal, the ligamentum flavum, undergoes hypertrophy (enlargement) and buckling. Third, the intervertebral discs may bulge backwards or herniate into the canal. Fourth, the vertebrae may slip forward in a condition called spondylolisthesis. Finally, these changes may be superimposed on a congenitally narrow canal.
The hallmark of lumbar stenosis is pain in the back and legs which is aggravated by standing and walking and relieved by sitting or forward bending. The syndrome of pain induced by walking is known as neurogenic claudication (from the Latin claudico, to limp). Neurogenic claudication must be distinguished from is vascular claudication, or leg pain on walking caused by insufficient blood flow to the legs. The features which help to distinguish neurogenic from vascular claudication are the following:
- Pain occurs after varying amounts of exercise, with standing, or with coughing. Vascular claudication is reliably produced with a fixed amount of exercise, such as walking a certain number of blocks, and is rare at rest.
- Pain relief with rest is variable and slow, usually requiring sitting or stooping. Resting in a standing position is usually not enough to relieve the pain and may even aggravate the pain. In contrast, the pain of vascular insufficiency is usually quickly relieved by resting in a standing position. This is the main distinguishing feature.
- Pain from spinal stenosis is usually in a distribution of a spinal nerve rather than the muscles exercised.
- Sensory loss is also in a nerve root distribution, while with vascular insufficiency it is in a stocking-glove distribution.
- Signs of vascular insufficiency should be absent: diminished pulses, foot pallor on elevation, and decreased temperature of the feet.
Spondylolysis and Spondylolisthesis
The most common cause of low back pain in adolescent athletes is a stress fracture in one of the vertebrae that make up the spinal column. Technically, this condition is called spondylolysis (spon-dee-low-lye-sis). It usually affects either the fourth or the fifth lumbar vertebra in the lower back. The fracture site is called a pars defect.
If the stress fracture weakens the bone so much that it is unable to maintain its proper position, the top vertebrae can shift forward on top of the bottom vertebrae. This condition is called spondylolisthesis (spon-dee-low-lis-thee-sis).
In adults, a spondylolisthesis is usually caused from degenerative changes in the spine. If too much slippage occurs, the bones may begin to press on nerves and surgery may become necessary to correct the condition.
- Genetics: There may be an inherited aspect to spondylolysis. An individual may be born with a thin vertebral bone and therefore may be predisposed to this condition. Rapid growth spurts in a teen may also encourage slippage.
- Overuse: Several types of athletics, such as gymnastics, weight lifting and football, put a great deal of stress on the bones in the lower back. They also require that the individual constantly over-stretch (hyperextend) the spine. In either case, the excessive stress can lead to fractures of the vertebrae.
- Spondylolisthesis may also develop because of degenerative changes in the vertebral joints and certain medical conditions such as cerebral palsy.
The sacroiliac joint connects the sacrum (the triangular bone at the bottom of the spine) with the pelvis (iliac crest). The joint:
- Transmits all the forces of the upper body to the pelvis (hips) and legs
- Acts as a shock-absorbing structure
- Does not have much motion
The sacroiliac joint can become inflamed from an acute injury or from chronic postural abnormalities such as undue stress on the joint following low back fusion surgery. Pain from sacroiliac joint abnormalities can occur in the low back, buttock/hip, abdomen, groin, or legs.
Ankylosing spondylitis primarily affects the spine or back. In a person with ankylosing spondylitis, the joints and ligaments that normally permit the spine to move become inflamed and stiff. The bones of the spine may grow together, causing the spine to become rigid and inflexible. Other joints such as the hips, shoulders, knees, or ankles also may become involved.
Other rare causes of back pain include:
- Benign or malignant tumors
- Problems of the digestive tract or genitourinary tract
- Vascular problems such as an aneurysm or hardening of the arteries