|Diseases of the spine|
Diseases of the spine
Because the spine is so complex and is the center of many of our activities, it is subject to a wide variety of diseases.
In this section, we will give an overview of these diseases, along with some of the common interventions:
Degenerative diseases of the spine
Degenerative spine disease is a major cause of chronic disability in the adult population. Spinal degeneration is a normal part of aging, and neck and back pain are one of life's most common problems. There are many potential sources of pain. Pain can originate from bone, joints, ligaments, muscles, nerves, and intervertebral disks as well as other paravertebral tissues.
Osteoporosis of the spine
Most of us think of bones as static, ridged, unchanging structures. In fact living bones are teeming with activities of many sorts. In fact, bones are continually restructuring: dissolving and reforming under the influence of external stresses.
Spinal stenosis is the narrowing of the spinal canal through which the spinal cord passes. Vertebral foramina enclose the spinal canal. Stenosis can be very serious if it compromises the spinal cord, resulting in pain, strange neural sensations, and even paralysis. It can be caused by a number of conditions, such as a ruptured disk or a dislocation of vertebrae, but here we will focus on the narrowing of the foramen because of vertebral degeneration.
With aging, the stability of the vertebrae, especially at the facet joints degenerates. To counter these stresses, the bone in the vertebrae thickens and the ligaments become thick and stiff. This results in a narrowing of the spinal canal. Stenosis can occur in the cervical, thoracic, lumbar, or all three regions.
Treatment options include physical therapy to strengthen back and abdominal muscles and increase flexibility. Medications can provide relief from mild symptoms. Pain-blocking injections can temporarily reduce inflammation of the spinal nerves and nerve roots. Surgery to remove pressure is usually recommended for patients with severe, persistent symptoms.
Lamenectomy is the most common surgical technique to relieve spinal cord or nerve branch compression due to stenosis. It involves the cutting of the vertebral lamina and the removal of the posterior portion of the vertebra.
You can see that now the vertebra has begun to compress the spinal cord.
Degeneration of the Intervertebral disk is often referred to as degenerative disk disease. The causes are manifold, including heredity, personal history, metabolism, and trauma. As we age, the nucleus pulposa becomes dessicated (looses water and flexibility). It is less able to absorb and distribute loads.
With time and/or trauma, the nucleus pulposus can extrude from a deteriorating annulus fibrosis. When severely weakened, a disk can rupture from even a slight trauma, such as a sneeze.When the disk is herniated, the nucleus penetrates the annulus. A herniated disk is also referred to as a ruptured disk or slipped disk.
Pressure on the spinal cord or nerve root is a common cause of back pain, often with pain radiating down the limbs, accompanied by numbness and/or tingling. If the bulging nucleus has not penetrated the annulus, treatment is relatively conservative in most cases: rest and lifting restrictions, heat and ice therapy, anti-inflammatory medications, cortisone injections. Medication to treat any associated pain.
After the nucleus has penetrated the annulus, it is irreversible. Often the nucleus tears, leaving permanent debris in the vertebral foramen. In severe cases, surgical intervention may relieve symptoms. There are many techniques, even replacing a disk with an articulating artificial disk.
Trauma to the spinal column
Vertebral fractures (often abbreviated as "Fx") are commonly classified into four groups:
As the name implies, compression fractures occur from excessive axial forces disrupting the continuity of the anterior column of the vertebral body. Osteoporosis is a leading precursor to compression fractures because of the vertebrae's lower ability to support a load. A missed step or even a cough can result in a compression fracture. People often accept back pain as a normal part of aging.
Repeated compression fractures can result in the loss of six inches or more in height. Another common cause of compression fracture is trauma, such as a fall. Click on the button below to witness a sudden vertical impact to the vertebral column.
Often, vertebral compression fractures eventually heal on their own. Aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) can be taken to relieve pain. More aggressive techniques include vertebroplasty, the injection of bone cement into the vertebra to stabilize it. Kyphoplasty is similar, but the vertebra is first expanded to near normal height and then stabilized with cement or mechanical devices. (See Interventions.)
Burst fractures usually occur from severe trauma such as a vehicle accident or a fall. Burst Fxs are more dangerous than compression Fxs for two reasons. The anterior and middle columns of the vertebral body are broken into several fragments, which are more likely to cause spinal cord injury. Since the vertebral body has lost its structural integrity, the spinal column is less stable.
If the burst Fx does not impinge on the spinal cord, it may be treated non-surgically. However, if there are loose fragments or nerve injury, surgery is usually performed.
The spine can be accessed anteriorly, posteriorly, or both. Loose fragments may be moved into a better position or removed. The spine may be reduced (elongated) for alignment. The fragments may be stabilized with screws and other mechanical means.
This type of fracture is sometimes called a "Chance" fracture. It was often caused by lap seat belts without shoulder restraints in cars. The initial collision can cause extreme flexion of the vertebral column, soon followed by the distraction of the rebound. In this fracture, all three columns of the vertebral body can fail and there may be injury to bone, ligaments and discs as well as other internal injuries.
Chance fractures are inherently unstable and require immediate intervention. These fracture types represent about 10% of lumbar spine fractures. The posterior column may be damaged by rupture of the spinus process or posterior longitudinal ligament, or both.
Fracture plus dislocation
Because of the large forces normally involved in a spine fracture, it is not unusual to also have a dislocation of the vertebrae. A dislocation tears the ligaments and/or disk. These fractures are usually unstable, seriously debilitating, and frequently require surgical repair.
Stable versus unstable fractures
If only the anterior column is damaged, as in the case of most wedge and compression fractures, the fracture is considered stable. When both the anterior and middle columns are involved, the fracture may be considered more unstable.
Deformities of the vertebral column
A deformity of the vertebral column is any significant deviation from the normal curves of the spine. The most common are
The term scoliosis was first used to describe this condition by Hippocrates in 400 BCE. It is a progressive disease whose origin is unknown (or idiopathic) in 80% of the cases, although there is evidence for a genetic and nutritional component. Females are at 10 times more risk than males. Scoliosis often includes a twisting of the spine, resulting in distortion of the ribs and entire thorax. It usually presents in pre-teens and adolescents. Structural scoliosis may require surgical intervention; alternatively scoliosis may be corrected using orthotics (e.g. braces).
The degree of deformity is defined buy the Cobb angle. Draw a line through the vertebra that is most curved below the apex of a curve. The angle it makes with a line drawn through the most curved vertebra above the apex is the Cobb angle. This individual displays a right lumbar curve of 53° and a left thoracic curvature of 30°. Choices of treatment range from do nothing for a mild case, applying a brace for an extended time, or surgery. Many factors enter into the choice, including age, overall health, and effect on critical organs.
In this case, open incisioninal spine surgery was used to place a major system of rods and pedicle screws. This achieved a remarkable degree of correction. However, the result is a non-flexible spine that may present more problems over time. More recent procedures favor less invasive techniques, using plates and screws to correct less severe cases. Both the lateral approach and the posterior approach are gaining favor. Typical incision length is 4" or less, and the technique is performed with the assistance of laparoscopy.
Kyphosis describes the natural curvatures of the thoracic spine, but hyperkyphosis a pathologically exaggerated thoracic curvature, commonly called "hunchback."
Hyperkyphos is common in aging adults, usually aided by the vertebral collapse related to osteoporosis. Other common causes may include trauma, arthritis, and endocrine or other diseases. "Dowager's hump" is a frequent result.
Here a modern custom-fit brace is designed to restore lumbar lordosis to a patient with thoracolumbar kyphosis. Results can be seen in the pre-treatment and post-treatment X-rays, respectively, at the right.
Hyperlordosis of the spine
Lordosis describes the natural curvature of the lumbar spine, but hyperlordosis is a pathologically exaggerated lumbar curvature, commonly called "swayback."
Hyperlordosis is usually accompanied by the pelvis tilting abnormally forward, often causing an exaggerated protrusion of the buttocks (See figures). Symptoms may include pain and numbness if the nerve trunks are compromised. Typically, the condition is attributed to weak back muscles or a habitual hyperextension, such as in pregnant women, men with excessive visceral fat, and some dance postures. Hyperlordosis is also correlated with puberty.
Treatment for hyperlordosis is not required unless it may progress, causes pain, or compromises nerves. Initially analgesics and anti-inflammatory medication are administered. Physical therapy to build strength, flexibility, and increase range of motion is common. The reduction to ideal body mass index is recommended. In adolescents, bracing may be applied to control progression.
There is no medical reason to group these diseases together, but we are training, and these terms are very often confused. "Spondylos " is ancient Greek for spine. The various suffixes describe specific and distinct diseases.
Spondylitis refers to any inflammation of the vertebra. It may or may not be associated with a degenerative disorder. (Remember, the -itis suffix refers to inflammation.)
"Ankylosing derives from the Greek for stiffening. It occurs when long-term spondylitis results in the edges of the vertebral bodies growing together into one body. This is also referred to as "bamboo spine" because the spine is stiff and resembles bamboo. There is a genetic association with the disease. It causes a gradual reduction in the ROM of the patient. It affects only about 0.2% of the population.
Spondylosis is caused by bony outgrowths (osteophytes) from the superior and inferior margins of the vertebral bodies. Lumbar spondylosis is usually asymptomatic (no pain), but cervical spondylosis can compromise the spinal cord, a serious problem.
Spondylolysis (from Greek "lysis," to dissolve) is a fracture in the posterior loop of the spinal column, most commonly in the lumbar region. The fracture is a result of excessive or repeated strain. The structure affected is called the pars interarticularis, the small part of bone connecting the superior and inferior articular facets, so physicians sometimes refer to this condition as a pars defect.
This is a younger person's disease, often associated with overtraining in active sports. There is also a hereditary correlation to weakness in the pars region, suggesting a genetic component.
The most common cause of spondylolisthis (Gr. -listhesis, a slip) is spondylolysis. It's not as complicated as it sounds. Spondylolysis is a fracture in the pars region. This loss of structural integrity allows the vertebral body to "slip" forward, resulting in spondylolisthis.
The most common form is "isthmic" spondylolithesis, caused by the fracture of the isthmus (neck) of the pars region. In older adults, spondylolisthesis can be caused by disk degeneration, without any pars defect.
Tumors of the spine
Spinal tumors are relatively uncommon. They can be benign or malignant (cancerous). Primary malignant spinal tumors are rare. Spinal malignancies usually result as a metastasis (spreading) from another malignant tumor.
Lateral CT scan showing sagittal view of a sacrococcygeal teratoma, the most common tumor found in newborns. SCTs also can occur in adolescents and adults. and may be benign or malignant.
Lateral CT scan showing sagittal view of an ependymoma. These are tumors of the ependyma, a tissue of the central nervous system. The majority are slow-growing and benign.
Surgical interventions for diseases of the spine are among the most commonly performed procedures. There are a large variety of techniques, with a definite trend to less invasive methods, often involving laparoscopes (relatively thin tubes that allow a visualization of the body's interior through a small incision).
A discectomy may be a more conservative choice to relieve pain caused by pressure from a ruptured nucleus pulposa. In this procedure, the protruding portion of the nucleus pulposa is removed. Then the remaining nucleus pulposa is extracted.
Spinal fusion, posterior approach
Spinal fusion is one of the more common surgical techniques for conditions where a disk and/or a vertebra is severely damaged. The principle is to remove the damaged segments, immobilize the vertebral bodies above and below the damaged structures, and stabilize the assembly.
Spinal fusion, anterior approach
Spinal fusion is one of the more common surgical techniques for conditions where a disk and/or a vertebra is severely damaged. The principle is to remove the damaged segments, immobilize the vertebral bodies above and below the damaged structures, and stabilize the assembly. (video)
A laminectomy is usually indicated when there is pressure from the vertebra on the spinal cord and/or nerve trunks. It is an attempt to remove a section of the vertebra and relieve the pressure on the nerves. In a laminectomy, either or both the laminae can be removed.
Kyphoplasty is a surgical procedure performed on a collapsed vertebra in an attempt to restore it to a normal height. After increasing height, the repair is stabilized. As an example of a minimally invasive kyphoplasty, we show a series of interlocking plates being serially injected, increasing the vertebral height. At the end, bone cement is injected throughout the structure to stabilize it. (video)
Diseases of the spine recap
We have learned about several classes of diseases that affect the spine. Some are due to age, genetics, trauma, or simply poor posture. Treatments can range from using pain relievers, physical therapy, bracing, or surgical interventions.
Some of the common surgical interventions we have reviewed: