Degenerative Disc Disease (DDD)
Approximately 60% of Americans over age 65 are affected by osteoarthritis, which is the main cause of degenerative disc disease (DDD). By the year 2050, it is estimated that more than 50% of individuals in western European countries over age 65 will be affected.
Aging involves all of the spine’s structures and there are many diseases and conditions that cause or contribute to back pain. Aging of the spine’s structural components may be related to hereditarily-predetermined cell vitality, tissue exposure to heavy mechanical forces during life, or just everyday wear and tear on spinal discs – the back’s shock absorbers – and may eventually cause deterioration.
DDD is a gradual process that usually begins with cracks and tears in the annulus, followed by arthritis in the facet joints, and/or spondylolisthesis, intervertebral disc herniation, development of bone spurs (osteophytes), and a collapse of one or more spinal segments. A collapse of a spinal segment may help relieve pain in some patients. The body’s natural response is to make bone, which stops the movement by fusing the segment.
Low back pain is one of the main reasons patients visit their physician. Eighty to 90% of people will experience an episode of acute low back pain during their lifetime. There is no consensus among medical professionals, however, on how to distinguish nonspecific back pain from back pain of a discogenic origin.
The classification of low back pain, as described by Moonye (1989) is based on the duration of the episode and can be useful in determining a possible cause. Low back pain was classified into the following categories:
- Acute back pain that lasts less than seven days and is generally related to soft tissue injury (tendon, ligament, and fascia) and has the highest potential for spontaneous recovery.
- Subacute back pain that persists longer than seven days, but less than three months and may involve the facet joints.
- Chronic back pain typically lasts longer than three months and is more likely to be disc-related.
Most episodes of back pain improve over time and without surgery. However, certain spinal problems may require surgical intervention. Causes of subacute and chronic back pain often involve significant structural damage and therefore treatment is indicated.
Initial therapy usually includes nonsurgical or conservative treatment. Depending on the cause of the symptoms may include medications (anti-inflammatories, muscle relaxants, oral steroids), physical therapy, massage, acupuncture, and possibly chiropractic treatment. Some patients may require interventional pain management treatments (epidural steroid injections, facet blocks).
Chronic back pain often is further classified into mechanical and back pain associated with sciatica. Mechanical back pain results from degenerative spinal changes, inflammation, or injury to the disc, ligaments or muscles. It typically presents as a pain felt in the lower spine and may radiate into the buttocks and thighs.
Sciatica is a term used to collectively describe low back pain that radiates through the left or right buttock into usually one leg sometimes including the foot. Back pain associated with sciatica occurs when the nerve roots that leave the spine are either irritated or pinched. The most common cause of this type of back pain is a ruptured or herniated disc. Rarely is sciatica caused by piriformis syndrome.
Lumbar Herniated Disc
A lumbar herniated disc (intervertebral disc) is a common cause of low back and leg pain (sciatica). The displacement or herniation (rupture) of the disc center presses on the nerves and causes pain, numbness or weakness in the leg.
While disc herniation occurs more often in adults age 50 or older, accidents and trauma affect all age groups. Many factors cause or contribute to the development of a herniated disc such as aging and degenerative disc disease wherein the structural integrity of lumbar discs declines.
Piriformis syndrome has been a controversial diagnosis since its initial description in 1928. Some physicians are skeptical that this condition even exists. Piriformis syndrome is usually caused by neuritis (or inflammation) of the proximal sciatic nerve. The piriformis muscle (located in the buttocks) can either irritate or compress the proximal sciatic nerve due to spasm and/or contracture, and this problem can mimic discogenic sciatica. Piriformis syndrome is also referred to as pseudo sciatica, wallet sciatica, and hip socket neuropathy. Pain can be a mild ache, sharp, or excruciating. Some patients experience feelings of burning, tingling, numbness, and weakness. A program of specific stretching exercise and corticosteroid injection often helps alleviate the symptoms. Rarely surgery is warranted.
Arthritis of the Facet Joints
Arthritis of the spine (osteoarthritis) can affect the facet joints. The facet joints are located between and behind adjacent vertebrae. Similar to other joints in the body, the facet joints enable the spinal extension, flexion, and rotation. Cartilage coats and helps to lubricate moving joint surfaces.
Such degeneration can cause loss of cartilage or joint hypertrophy – enlargement of the joint. Common symptoms include joint stiffness and pain.
Spondylolisthesis occurs when one vertebral body slips forward on the adjacent vertebrae. It may be congenital (present at birth), develop during childhood, or acquired during adulthood. Causes of acquired spondylolisthesis include physical sports such as weightlifting or gymnastics, accumulated spinal stress (daily wear and tear), and degenerative or age-related changes to the spine that causes stabilizing structures to become weak. Typical symptoms include low back pain, sciatica, muscle spasms, leg weakness, tight hamstring muscles, and problems walking.
During the diagnostic process, the slip is graded (from 1 to 5) to classify the degree of the spondylolisthesis. The grade and other factors, such as slip progression, pain, and neurological symptoms are considered when deciding on the treatment.
Lumbar Spinal Stenosis and Neurogenic Claudication
Spinal stenosis refers to a narrowing of the spinal canal and may involve the central canal, foramen, or lateral recess. The central canal houses and protects the spinal cord, the foramen are the nerve passageways between the vertebral bodies (foraminal spinal stenosis), and the lateral access is where the lumbar nerve roots exit the spinal column (lateral recess stenosis).
Sometimes spinal stenosis is congenital – meaning it is present at birth. However, the majority of cases are age-related and affect people age 50 and older.
Symptoms can make standing, walking, sitting, and other everyday activities difficult. Symptoms typically include:
- Radiculopathy (foraminal stenosis)
- Neurogenic claudication (central canal stenosis)
In addition to the patient’s medical history, physical and neurological examination, diagnostic tests may be necessary. Tests may include x-ray, CT scan (Computed Tomography), MRI (Magnetic Resonance Imaging), bone scan, Electromyography (EMG), and / or diagnostic injections.
X-rays (or radiographs) help to identify a bone-related problem, such as a fracture. MRI provides a highly detailed rendering of spinal anatomy and is performed if the disc, ligament, spinal cord or nerve root involvement is suspected.
If back pain is considered to be discogenic – caused by an intervertebral disc, discography (discogram) may be recommended. Indications for discography include a protruding, herniated, fixated disc, or for surgical planning of lumbar fusion or artificial disc replacement.
Discography is an invasive procedure that involves injection of a radiographic contrast medium (dye) into the nucleus of a disc. Sometimes discography replicates pain or symptoms (provocative discography) or helps to rule out a disc-related problem. In addition, discography can be useful to evaluate discs adjacent to previously fused lumbar segments. Lumbar discography is contraindicated in patients with a calcified disc herniation and severe degenerative facet disease.
Opinions about the indications for and results provided by discography are a controversial topic among some physicians. This controversy may stem from past technological limitations. However, it should be remembered that any diagnostic test, including discography, can produce a false positive and false-negative result. Modern advancements in fluoroscopic guidance improve needle placement, the accuracy of intranuclear injections, and requires less contrast. These developments have led to discography becoming a more sensitive and specific diagnostic tool to evaluate intervertebral discs.