Few adults get through life without occasional back pain — the price paid for walking upright with a spine not perfectly suited to the task. Most back pain stems from normal stresses and strains or from degenerative changes that come with aging. But sometimes the cause may be a spinal tumor — a cancerous or noncancerous growth that develops within or near the spinal cord or in the bones of the spine.
In most areas of the body, noncancerous tumors aren't particularly worrisome. Yet that's not necessarily the case with the spinal cord, where a spinal tumor or a growth of any kind can impinge on crucial nerves, leading to pain, neurological problems and sometimes paralysis. In fact, a spinal tumor, whether cancerous or not, can threaten life and cause permanent disability. Yet advances in spinal tumor treatment offer more options than ever before to people with these tumors.
In most animals, the spine functions as a suspension bridge, but in humans, the "bridge" has been upended and turned into a weight-bearing column. As a result, your spine provides structural support for your body while at the same time allowing flexible movement. The structure of the spine is complex and includes bones, cartilage, ligaments, joints and nerves. Of these, the vertebrae and spinal cord are the most important for an understanding of spinal tumors.
- Vertebrae. The spine is made up of 24 small bones stacked on top of one another, plus the sacrum and tailbone (coccyx). Most adults have seven of these bones in the neck (cervical vertebrae), 12 at the back wall of the chest (thoracic vertebrae) and five at the inward curve of the lower back (lumbar vertebrae). The sacrum consists of five fused vertebrae between the hip bones. The tailbone is formed from three to five bones fused at the very end of the spine. Each vertebra has an opening in the center, much like the hole in a doughnut. Stacked together, the holes form a hollow channel (spinal canal) that encloses and protects the spinal cord and its nerve roots.
- Spinal cord. Your spinal cord is a long column of nerve fibers that carries messages to and from your brain. It extends from the base of your skull to the second lumbar vertebra in your lower back. The spinal cord is usually 15 to 17 inches long, but its circumference varies at different points along your spine. At its widest, in the nerve-rich cervical and lumbar areas, it's about the diameter of your thumb. Structurally, the spinal cord is a double-layered tube: The butterfly-shaped inner layer (gray matter) contains nerve cells, supporting cells called glia and blood vessels. The outer layer is primarily white matter — nerve fibers (axons) that relay sensory information such as pain and temperature from your body to your brain and conduct motor impulses from your brain to your muscles, organs and glands. The axons are bundled into 31 pairs of spinal nerves, with one sensory nerve root and one motor nerve root in each pair. The paired nerves extend out from the spinal cord between each vertebra. Wrapped around the entire spinal cord are three protective membranes (meninges) made of connective tissue: The innermost membrane is the pia; the arachnoid, so named because of its resemblance to a spider web, lies in the middle. The tough, outer membrane, to which the spinal nerves attach, is the dura.
Types of spinal tumors
Spinal tumors are classified according to their location in the spine.
- Vertebral tumors. Most tumors that affect the vertebrae have spread to the spine from another site in the body — often the prostate, breast, lung or kidneys. Although the original (primary) cancer is usually diagnosed before back problems develop, back pain may be the first symptom of disease in many people with metastatic spinal tumors. Cancerous tumors that originate in the bones of the spine are far less common. Among these are osteosarcomas (osteogenic sarcomas), the most common type of bone cancer in children, and Ewing's sarcoma, a particularly aggressive tumor that affects young adults. Benign tumors such as osteoid osteomas, osteoblastomas and hemangiomas also can develop in the bones of the spine where they may cause long-standing pain, spinal curvature (scoliosis) and neurological problems.
- Intradural-extramedullary tumors. These tumors develop in the spinal cord's arachnoid membrane (meningiomas), in the nerve roots that extend out from the spinal cord (schwannomas and neurofibromas) or at the spinal cord base (filum terminale ependymomas). Meningiomas occur most often in women between the ages of 40 and 70. Although almost always benign, they can be difficult to remove and may sometimes recur. Nerve root tumors also are generally benign, although neurofibromas can become malignant over time. Ependymomas at the end of the spinal cord are often large, and their treatment may be complicated by the extensive system of nerves in that area.
- Intramedullary tumors. These tumors begin in the supporting cells within the spinal cord. Most are either astrocytomas, which mainly affect children and adolescents, or ependymomas — the most common type of spinal cord tumor in adults. Intramedullary tumors can be either benign or malignant and, depending on their location, may cause numbness, loss of feeling, or changes in bowel and bladder function.
Spinal tumor origins a mystery
Although scientists are learning more about the genetic and environmental factors involved in the development of many kinds of tumors, spinal tumors are still a relatively unknown quantity. Spinal tumors often contain a number of abnormal genes, but in many cases, researchers don't know what causes these genetic alterations. They do know that in some cases, spinal cord tumors run in families and are associated with familial cancer syndromes such as :
- Neurofibromatosis 2. In this hereditary disorder, benign tumors develop on or near the nerves related to hearing, leading to progressive hearing loss in one or both ears. Some people with neurofibromatosis 2 also develop tumors in the arachnoid layer of the spinal cord or in the supporting glial cells.
- Von Hippel-Lindau disease. This rare, multisystem disorder is associated with benign blood vessel tumors (hemangioblastomas) in the brain, retina and spinal cord and with other types of tumors in the kidneys or adrenal glands.
It's also known that spinal cord lymphomas — cancers that affect lymphocytes, a type of immune cell — are more common in people whose immune systems are compromised by medications or disease.
When to seek medical advice :
Most back pain isn't the result of a spinal tumor. But because early diagnosis and treatment are important for many back problems, see your doctor if you have persistent back pain that isn't activity-related, that gets worse at night or that isn't relieved by over-the-counter analgesics. Symptoms such as progressive muscle weakness or numbness in your legs and changes in bowel or bladder function require immediate medical attention.
Back pain, especially in the middle or lower back, is the most frequent symptom of both noncancerous (benign) and cancerous (malignant) spinal tumors. The pain may be worse at night or on awakening. It also may spread beyond your spine to your hips, legs, feet or arms and may become more severe over time in spite of treatment.
Depending on the location and type of tumor, other signs and symptoms can develop, especially as a malignant tumor grows and impinges on the spinal cord or on the nerve roots, blood vessels or bones of your spine. These signs and symptoms include :
- Loss of sensation or muscle weakness, especially in your legs
- Difficulty walking, sometimes leading to falls
- Decreased sensitivity to pain, heat and cold
- Loss of bowel or bladder function
- Paralysis that may occur in varying degrees and in different parts of the body, depending on which nerves are compressed
- Scoliosis or other spinal deformity resulting from a large but benign tumor
Spinal tumors progress at different rates. In general, malignant tumors grow quickly, whereas benign tumors may develop slowly, sometimes existing for years before causing problems.
Spinal tumors sometimes may be overlooked because they're rare and because their symptoms resemble those of conditions that are much more common. For that reason, it's especially important that your doctor know your complete medical history and perform both physical and neurological exams. If your doctor suspects a spinal tumor, one or more of the following tests can help confirm the diagnosis and pinpoint the tumor's location :
- Spinal magnetic resonance imaging (MRI). Instead of radiation, MRI uses a powerful magnet and radio waves to produce cross-sectional images of your spine. MRI accurately shows the spinal cord and nerves and yields better pictures of bone tumors than computerized tomography (CT) scans do. A contrast agent that makes certain tumors light up may be injected into a vein in your hand or forearm before the test. In addition, some medical centers use high field strength scanners to find small tumors that might otherwise be missed. You may feel claustrophobic inside the scanner or find the loud thumping sound it makes disturbing. But you're usually given earplugs to help with the noise, and some scanners are equipped with televisions or headphones. If you're very anxious, your doctor may prescribe a mild sedative.
- Computerized tomography (CT). This test uses a narrow beam of radiation to produce detailed, cross-sectional images of your spine. Sometimes it may be combined with an injected contrast dye to make abnormal changes in the spinal canal or spinal cord easier to see. Although not invasive, this test exposes you to more radiation than a regular X-ray does.
- Myelogram. In this test, a contrast dye is injected into your spinal column. The dye then circulates around your spinal cord and spinal nerves, which appear white on an X-ray or CT scan. Because the test poses more risks than MRI or conventional CT, a myelogram is usually not the first choice for diagnosis, but it may be used to help identify compressed nerves.
- Biopsy. The only way to determine whether a tumor is benign or malignant is to examine a small tissue sample (biopsy) under a microscope. If the tumor is malignant, biopsy also helps determine the cancer's grade — information that helps determine treatment options. Grade 1 cancers are generally the least aggressive and grade 4 cancers, the most aggressive. How the sample is obtained depends on your overall health and the location of the tumor. Your doctor may use a fine needle to withdraw a small bit of tissue, or the sample may be obtained during an operation.
Both benign and malignant spinal tumors can compress spinal nerves, leading to a loss of movement or sensation below the level of the tumor and sometimes to changes in bowel and bladder function. Nerve damage is often permanent, and disabilities are likely to continue even after the tumor is removed. Depending on its location, a tumor that impinges on the spinal cord itself may be life-threatening.
Ideally, the goal in treating a spinal tumor is to eliminate the tumor completely, but this aim is complicated by the risk of permanent damage to the surrounding nerves. Doctors also must take into account your age, overall health, the type of tumor and whether it is primary or has spread to the spine.
Treatment options for most spinal tumors include :
- Monitoring. Sometimes spinal tumors are discovered before they cause symptoms — often when you're being evaluated for another condition. If small tumors are benign and not growing or pressing on surrounding tissues, watching them carefully may be the only treatment that's needed. This is especially true in older adults for whom surgery or radiation therapy may pose special risks. If you decide not to treat a spinal tumor, your doctor will recommend periodic scans to monitor the tumor's growth.
- Surgery. This is often the first step in treating tumors that can be removed with an acceptable risk of nerve damage. What's more, new techniques and instruments allow neurosurgeons to reach tumors that were once inaccessible. The high-powered microscopes used in microsurgery, for instance, make it easier to distinguish tumors from healthy tissue. Doctors also can test different nerves during surgery with electrodes, thus minimizing neurological damage. And in some instances, they may use sound waves to break up tumors and remove the remaining fragments. But even with these advances in treatment, not all tumors can be removed completely. Surgical removal is the best option for many intramedullary and intradural-extramedullary tumors, yet large ependymomas at the end of the spine may be impossible to extricate from the many spinal nerves in this area. And although benign tumors in the vertebrae can usually be completely removed, metastatic tumors are less likely to be operable. When a tumor has metastasized to the spine, radiation is usually the treatment of choice. In these cases, surgery is reserved for people who don't have a diagnosis, who have tumors resistant to radiation or recurrent tumors that were previously irradiated. Recovery from spinal surgery may take weeks or months, depending on the procedure, and you may experience a temporary loss of sensation or other complications, including bleeding and damage to nerve tissue.
- Radiation therapy. This may be used following an operation to eliminate the remnants of tumors that can't be completely removed or to treat inoperable tumors. It's also the first-line treatment for metastatic tumors. Radiation may also be used to relieve pain or when surgery poses too great a risk. Medications can help some of the side effects of radiation, such as nausea and vomiting. And depending on the type of tumor, your doctor may be able to modify your therapy to help prevent damage to surrounding tissue and improve the treatment's effectiveness. Modifications may range from simply changing the dosage of radiation you receive to using sophisticated techniques that offer better protection to healthy tissue, such as three-dimensional conformal radiation therapy.
- Chemotherapy. A standard treatment for many types of cancer, chemotherapy hasn't proved beneficial for most spinal tumors because the drugs can't cross the blood-brain barrier, a complicated network of fine blood vessels and cells that filters blood entering the central nervous system. Researchers are investigating drugs that they hope will help open the barrier, making it more amenable to drug treatment.
- Other drugs. Because surgery and radiation therapy as well as tumors themselves can cause inflammation inside the spinal cord, doctors sometimes prescribe corticosteroids to reduce the swelling, either following surgery or during radiation treatments. Although corticosteroids reduce inflammation, they are usually used for short periods only to avoid such serious side effects as osteoporosis, high blood pressure, diabetes and an increased susceptibility to infection.
|Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.