Compression fractures of the spine usually occur at the bottom part of the thoracic spine and the first vertebra of the lumbar spine. They can be extremely painful and can cause neurological disfunction such as leg weakness or disturbances in bowel or bladder function.

Spinal Compression Fracture

Causes

Compression fractures of the spine are caused by excessive forces on the vertebral body. This usually results from a combination of bending forward and downward pressure on the spine. The fracture occurs when the bone actually collapses and the front (anterior) part of the vertebral body forms a wedge shape. The front of the vertebral body is crushed, or compressed. In very severe compression fractures (fortunately not a common occurrence), the back of the vertebral body may actually protrude into the spinal canal and put pressure on the spinal cord.

Underlying causes can include:

• Osteoporosis. Vertebral fractures most commonly arise due to severe osteoporosis, a progressive loss of bone mass most often seen in post-menopausal women. Osteoporosis thins the bones, often to the point that they are too weak to bear normal pressure. The thinning bones can collapse during normal activity, leading to a spinal compression fracture. Forty percent of all women will have at least one by the time they are 80 years old. These vertebral fractures can permanently alter the shape and strength of the spine. The fractures often heal without medical intervention and the pain eventually goes away. However, sometimes the pain can persist if the crushed bone fails to heal adequately.
  In severe cases of osteoporosis, actions as simple as bending forward can be enough to cause a spinal compression fracture. This type of vertebral fracture causes loss of height and a humped back, especially in elderly women. This disorder (called kyphosis or a “dowager’s hump”) is an exaggerated forward curvature of the spine that causes the shoulders to slump forward and the top of the back to look enlarged and humped.
• Trauma to the spinal vertebrae can also lead to minor or severe fractures. Such trauma could come from a fall, a forceful jump, a car accident, or any event that stresses the spine past its breaking point.
• Metastatic Disease. Another cause of vertebral fractures is a metastatic disease — the spread of cancer cells from their primary site into other areas of the body. The bones of the spine are a common place for many types of cancers to spread. A compression fracture of the spine that appears for little or no reason may be the first indication that an unrecognized cancer has spread to the spine. The cancer causes destruction of part of the vertebra, weakening the bone until it collapses.

Symptoms

If the fracture is caused by a sudden, forceful injury, you will probably feel severe pain in your back, legs, and arms. You might also feel weakness or numbness in these areas if the fracture injures the nerves or the spine. If the bone collapse is gradual — such as a fracture from bone thinning, the pain will usually be milder. There might not be any pain at all until the bone actually breaks.

Diagnosis

In order for a fracture to be diagnosed, your doctor will take your complete history and physical examination. There are many possible internal causes of pain. It is important to determine the root of the problem. After the physician has a better idea of what is causing your discomfort, diagnostic tests of some sort may be recommended.

Physical examination. If a compression fracture is suspected, the doctor will also test for point tenderness near specific vertebrae. Testing specific areas for unusual tenderness allows the doctor to narrow down the cause of your pain.

A neurological exam will also be given, allowing the doctor to test your reflexes, muscles, and sensory perception. Abnormalities on the neurological examination can point to nerve damage. The nerves of the spinal cord carry messages from the brain to the rest of the body. If there is damage to the spinal nerves, your body movement and neurological responses will be affected.

X-ray. If a fracture is thought to exist, an X-ray of the spine will generally confirm its presence. An X-ray is a painless process that uses radioactive materials to take pictures of bone. X-rays show bones, but not much soft tissue, so X-rays will definitely be used if fractures are suspected.

CAT (or CT) scan. Your doctor may also order a CAT scan to make sure that the fracture is stable. With a compression fracture, an up and down perspective of the spine will be pieced together for examination of stability. The CAT scan provides the most detailed view of the bones

MRI. If there is a chance that nerves are involved in the fracture, or if there is some question about what is causing the pain, an MRI might be recommended. The MRI is able to cut through multiple layers of the spine and show any abnormality of soft tissues, such as nerves and ligaments.

A nuclear bone scan is another diagnostic test that might be ordered. This test helps determine the age of a fracture. If the fracture is old and there appear to be other fractures that have healed, this may indicate osteoporosis (bone-thinning disease) is causing the fractures. In this case, treatment of the fracture will include preventive measures to try to stop other vertebral fractures from occurring. Such treatment could include: calcium supplements, increased vitamin D, weight-bearing exercises, and hormone replacement therapy for women.

Treatment

The most common treatments for a thoracic compression fracture are:

• Pain medications
• Decreasing activity
• Bracing
• In rare cases, surgery may also be necessary.

Your doctor may prescribe a back support (often officially called an orthosis) to support he back and keep you from bending forward. It holds the spine in hyperextension (meaning more extension, or straightening, than normal). This takes most of the pressure off the fractured vertebral body, and allows the vertebrae to heal. It also protects the vertebra and stops further collapse of the bone. The brace is well molded to conform tightly to your body, like a cast for any other fracture.

Vertebral fractures usually take about three months to fully heal. X-rays will probably be taken monthly to check on the healing progress.

While surgery is rarely needed, vertebroplasty or kyphoplasty (“cement injection”) may be considered if there is evidence of sudden and serious instability of the spine. For instance, if the fracture leads to a loss of 50% of the vertebral body’s height, surgery might be necessary to prevent damage that is more serious to the spinal nerves. Internal fixation is used to hold the vertebrae in the proper position while the bone heals. If there are signs that there is too much pressure on the spinal cord, the bone fragments pushing into the spinal cord may also need to be removed.

Achondroplasia is a genetic (inherited) bone disorder that occurs in one in 25,000 live births. Achondroplasia is the most common type of dwarfism, in which the child’s arms and legs are short in proportion to body length. Further, the head is often large and the trunk is normal size. The average height of adult males with achondroplasia is 52 inches (or 4 feet, 4 inches). The average height of adult females with achondroplasia is 49 inches (or 4 feet, 1 inch).

What causes achondroplasia?

Achondroplasia is inherited by an autosomal dominant gene that causes abnormal cartilage formation. Autosomal dominant inheritance means that the gene is located on one of the autosomes (chromosome pairs 1 through 22). This means that males and females are equally affected. Dominant means that only one gene is necessary to have the trait. When a parent has a dominant trait, there is a 50 percent chance that any child they have will also inherit the trait. So, in some cases, the child inherits the achondroplasia from a parent with achondroplasia. The majority of achondroplasia cases (80 percent), however, are the result of a new mutation in the family – the parents are of average height and do not have the abnormal gene.
As mentioned, persons with achondroplasia have a 50 percent chance to pass the gene to a child, resulting in the condition. If both parents have achondroplasia, with each pregnancy, there is a 50 percent chance to have a child with achondroplasia, a 25 percent chance that the child will not inherit the gene and be of average height, and a 25 percent chance that the child will inherit one abnormal gene from each parent, which can lead to severe skeletal problems that often result in early death.

Geneticists have found that fathers who are older than 45 have a higher chance of having children with certain autosomal dominant conditions such as achondroplasia, but no cause for the new mutations in sperm has been discovered at this time.

The gene responsible for achondroplasia was discovered in 1994 making accurate prenatal diagnosis available, in most cases.

What are the symptoms of achondroplasia?

The following are the most common symptoms of achondroplasia. However, each child may experience symptoms differently. Symptoms may include:

• small vertebral canals (back bones) – may lead to spinal cord compression in adolescence. Occasionally children with achondroplasia may die suddenly in infancy or early childhood in their sleep due to compression of the upper end of the spinal cord, which interferes with breathing.
• shortened arms and legs, with the upper arms and thighs more shortened than the forearms and lower legs
• large head size with prominent forehead and a flattened nasal bridge
• crowded or misaligned teeth
• curved lower spine – a condition also called lordosis (or “sway-back”) which may lead to kyphosis, or the development of a small hump near the shoulders that usually goes away after the child begins walking.
• bowed lower legs
• flat feet that are short and broad
• extra space between the middle and ring fingers (Also called a trident hand.)
• poor muscle tone and loose joints
• frequent middle ear infections which may lead to hearing loss
• normal intelligence
• delayed developmental milestones such as walking (which may occur between 18 to 24 months instead of around one year of age)

The symptoms of achondroplasia may resemble other problems or medical conditions. Always consult your child’s physician for a diagnosis.

How is achondroplasia diagnosed?

Achondroplasia can be diagnosed before birth by fetal ultrasound or after birth by complete medical history and physical examination. DNA testing is now available before birth to confirm fetal ultrasound findings for parents who are at increased risk for having a child with achondroplasia. MRI is the study of choice to diagnose spinal cord or nerve root compression.

Treatment of achondroplasia:

When present, spinal cord compression can be very successfully treated with various operations to decompress the spinal canal. Frequently these occur at the top of the spinal column or at the lower end. Both are commonly treated by our pediatric neurosurgeons. Currently, there is no way to prevent or treat achondroplasia, since the majority of cases result from unexpected new mutations. Treatment with growth hormone does not substantially affect the height of an individual with achondroplasia. Leg-lengthening surgeries may be considered, in some very specialized cases.

Detection of bone abnormalities, particularly in the back, are important to prevent breathing difficulties and leg pain or loss of function. Kyphosis (or hunch-back) may need to be surgically corrected if it does not disappear when the child begins walking. Surgery may also help bowing of the legs. Ear infections need to be treated immediately to avoid the risk of hearing loss. Dental problems may need to be addressed by an orthodontist (dentist with special training in the alignment of teeth.)

There is research into the family of genes called fibroblast growth factors, in which the gene that causes achondroplasia is included. The goal is to understand how the faulty gene causes the features seen in achondroplasia, in order to lead to improved treatment. These genes have been linked to many heritable skeletal disorders.