Archive for July, 2011

Spine Tumors: Primary and Secondary

“Tumor” is a word about which nothing good can be said. It can cause terror in the mind of the listener, especially if the person speaking is their doctor. The word “Tumor” is an ancient Latin word that meant “swelling” on or in the human body. It was thought to be one of the five signs of inflammation (i.e., pain (dolor), heat (calor), redness (rubor), tumor (swelling), and loss of function (functio laesa)). In the contemporary medical lexicon, tumor still means an abnormal swelling of the flesh. It is also considered synonymous with neoplasm, which is a medical term for an abnormal, uncontrolled growth of new cells.

TumGraphic of a Spine Tumorors & Cancer

To the lay person, a tumor is more often than not considered to be synonymous with cancer. However, a tumor can be non-cancerous (benign), pre-cancerous (carcinoma in-situ), or cancerous (malignant). A benign tumor does not consume other tissues and will not become malignant overtime. It will, however, continue to grow in size and can cause pain and system dysfunction. A pre-cancerous tumor falls somewhere in between a benign tumor and a malignant tumor. It has the potential to become cancerous, but its growth has not yet become uncontrolled. In its pre-cancerous state the tumor should be a cause for concern and periodically monitored. Pre-cancerous tumors often appear as moles or uterine fibroids.

In a malignant tumor the cells grow uncontrollably and more quickly than benign tumor cells. They seek out other tissue to consume. Unlike a self-contained or non-spreading benign tumor, a malignant tumor will continue to spread to other parts of the body. Malignant tumors are, by definition, always cancerous. Fortunately they are not contagious, but they are also not preventable.

Q: Where are tumors most often located?

A: Tumors, either benign or malignant, can be located anywhere in the body. They can occur in the vital organs (e.g., brain, liver, lungs, kidney, etc.), soft tissues, bone/bone marrow, blood vessels, etc. Tumors in bone, including the spine, are classified as being primary or secondary. The primary spinal tumor first appears in the bones of the spine, whereas a secondary spinal tumor (always malignant) first appears elsewhere in the body and metastasizes (spreads) to the spine. Some spinal tumors occur as a result of genetic defects (e.g., neurofibromatosis 2), for the remainder the pathogenesis or cause is unknown.

Q: How often does spine cancer occur?

A: The answer to this is difficult to quantify. However, the spine is the most common site for bone metastasis. There are estimates that suggest between 30 and 70% of all patients with cancer will have spinal involvement.

Q: Where are the spinal tumors located?

A: Primary and secondary spinal tumors can occur (1) inside the spinal cord (intramedullary), (2) in the membrane (the meninges) that covers the spinal cord (extramedullary-intradural), or (3) between the meninges and the bones of the spine (extradural). Although a small number of tumors occur in the nerves of the spinal cord (e.g., ependymomas and gliomas), the majority of spinal tumors are extradural. Primary spinal tumors are much less common than primary brain tumors. As a spine tumor grows it can place pressure on the spinal cord as well as the bones of the spine, spinal blood vessels, nerve roots and the meninges.

In men, the secondary tumors that most often spread to the spine originate in the prostate and lung. In women, the secondary spine tumors most often originate in the breast and lung. Malignant spine tumors can also originate in the kidney, thyroid, and malignant melanoma. The cancerous cells are then transported to the spine via the lymphatic system or blood.

Q: Is there more than one type of spinal tumor?

A: There are a number of different types of both benign and malignant spinal tumors.

Among the benign tumors that may be present in the spine are:

Aneurysmal bone cyst – an abnormal growth that affects the vertebrae. Treatment includes embolization (cutting off blood flow) and surgical removal

Hemangioma – usually found in the thoracic and lumbar spine. Treatment includes embolization (cutting off blood flow), surgical removal and radiation

Giant cell tumor – an uncommon tumor found in the sacrum and lumbar spine. Treatment includes embolization (cutting off blood flow), surgical removal and possibly radiation

Osteoblastoma – found in the vertebrae and sacrum. Treatment is most often surgical removal

Osteoid Osteoma – found in the spinal column. Treatment is most often surgical removal.

More than 70% of all spine tumors are malignant, of which only 10% originate in the spine.

Among the primary malignant tumors that may be present in the spine are:

Multiple myeloma (cancer of the bone marrow) – most common malignancy of the spine. Treatment includes surgical removal, radiation and chemotherapy. The chemotherapy may be administered before the surgery to shrink the tumor (neoadjuvant chemotherapy) or after the surgery (adjuvant chemotherapy) to destroy any remaining cancerous cells.

Chondrosarcoma – most commonly found in the thoracic spine. Treatment is most often surgical removal

Chordoma – usually found in the lumbar spine and sacrum. Treatment is most often surgical removal if it can be done without affecting nearby nerve structures. Radiation may also be used for treatment.

Non-Hodgkin’s lymphoma – sometimes found in a vertebra and spinal canal. Treatment includes surgical removal, radiation and chemotherapy

Osteosarcoma – rarely found, affects the lumbar and sacral spine. Treatment includes surgical removal, radiation and chemotherapy

Ewing’s sarcoma – rare in persons over 30. Found in the sacrum, lumbar and thoracic vertebrae. Treatment is most often surgical removal combined with radiation and chemotherapy

Plasmacytoma – affects the thoracic vertebrae and can cause compression fracture. Treatment includes surgical removal and radiation

Astrocytomas – affect the nerve cells of the spinal cord. Treatment includes surgery and radiation.

Q: What are the symptoms of a spinal tumor?

A: The symptoms of a spinal tumor depend on the location, type of the tumor and rate of growth. Non-mechanical pain in the thoracic and lumbosacral regions of the back is the most frequent symptom. However, pain in the back is common to many spinal pathologies (cysts, infections, compression fractures, herniated discs, medication complications, etc.) and therefore an accurate diagnosis of a spinal tumor is critical. Other symptoms of a spinal tumor include bone fracture, swelling and inflammation, sciatica, loss of sensation, loss of bowel or bladder function, scoliosis or other spinal deformity. To isolate and pinpoint the spinal tumor the back and neck specialist will usually order a variety of lab tests to be performed (e.g., complete blood count with diff, comprehensive metabolic panel, serum protein electrophoresis, acid phosphatase, urinalysis with Bence Jones Protein, etc.).

In addition, one or more imaging studies may be undertaken, e.g., plain x-ray, MRI with contrast medium, CT Scan with Myelogram, Technetium bone scan or other nuclear medicine bone scans, or positron emission tomography (PET) scan.

Q: Assuming a tumor is found, what next?

A: To determine the exact type of tumor the back and neck specialist will have the patient undergo a needle biopsy (with image guidance) to obtain a sample of the tumor tissue so that the exact type, stage (severity) and grade (how quickly the cancer is likely to spread – low grade tumors being the least aggressive) of the cancer can be determined. Once this is done, a decision is made as to the treatment that will be pursued. This may mean a non-surgical treatment approach such as observation, the use of corticosteroids, palliative drug therapy, radiation, chemotherapy (administered in pill form, injection, intravenously, or via an implanted vascular access device (VAD)), bone marrow aspiration, radio-frequency ablation, or, in some cases, stem cell transplants.

Surgery is recommended when (1) other treatments have failed, (2) it is deemed necessary to stabilize the spine, or (3) the spinal nerves are being compressed. In this case all or a part of the tumor will be removed. During this procedure the surgeon will attempt to stabilize and reconstruct the spine by performing a spinal fusion with bone grafts, use of bone cement and instrumentation. Tumors that were found to have aggressive microscopic (histopathological) characteristics are subject to post-operative radiation therapy.

Q: Is spinal tumor surgery a high risk operation?

A: There are risks associated with any spinal surgery. These include infection, post-operative neurological problems, residual pain, failure to excise the entire tumor due to structural considerations, etc.

Q: If the decision is for the spine tumor to be removed by surgery, how long can I expect to be in the hospital?

A: Hospital stay can be up to 10 days or longer depending on complications, followed by bed rest and possibly rehabilitation.

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Vertebral Compression Fracture

The human spine extends from the skull to the pelvis and is the primary structural component of the body. It consists of 33 bones (vertebrae) stacked in a vertical column held in place by a complex assortment of back muscles, ligaments and tendons. The spinal column serves to (1) protect the spinal cord and the 31 pairs of nerve roots that branch off the spine; (2) provide stability and support for the head, chest and shoulders allowing the body to stand and walk upright; and, (3) and enables flexibility and mobility of the upper body. Adjacent vertebrae are separated by a fibrocartilaginous disc that serves as a shock absorber by cushioning the stress forces placed on the spine when the individual walks, runs or jumps. The intervertebral discs account for one-quarter to one-third of the spine’s length. The hollow center of the vertebrae create a canal or tunnel that houses a collection of nerve fibers known as the spinal cord, which originates at the base of the brain and ends at the first lumbar vertebra. The spinal cord and the brain are the primary components of the central nervous system.

The vertebrae of a healthy spine can withstand considerable pressure, but when the compressive force being applied exceeds the load limit of the bone, one or more vertebrae can collapse causing a decrease in the intervertebral space and the height of the vertebra. This is usually accompanied by a vertebral compression fracture that is most commonly located in the thoracic spine (primarily at T7-T8 and T12 and L1 – the thoracolumbar junction). Vertebral compression fractures can also be caused by trauma to the spine as a result of (1) automobile accidents, falls, sports injuries or improper lifting of heavy objects; (2) localized infection of the bone (osteomyelitis); (3) cancer in the vertebra that has metastasized from the liver, colon, prostate, breasts or lungs; or, (4) long-term use of steroid medication.

The most common cause of compressive spinal fractures is osteoporosis. In the U.S. alone, it is estimated that this bone-weakening, metabolic disease is the cause of between 750,000 and 800,000 vertebral compression fractures annually. If the osteoporotic or other type of compressive fracture impacts the spinal cord or nerve roots the individual usually experiences acute pain. However, in the case of osteoporosis, more than two-thirds of the fractures are atraumatic (i.e., clinically silent) even though they may occur at several levels of the spine. This means that the individual experiences little or no discomfort from a neurological deficit (the risk still exists that additional compressive fractures may occur). If mild pain does occur it usually goes away within a few weeks. In older patients the pain is often attributed to the natural aging process and is tolerated by the individual without seeking a medical evaluation. Symptoms of a compressive fracture other than pain include loss of body height, pain when standing or walking, evidence of kyphosis (dowager’s hump or humpback at the top of the back which is common in older women), loss of balance, psychological disturbances or neurological symptoms such as numbness and tingling.

If not treated properly vertebral compression fractures can lead to (1) a progressive misalignment, segmental instability and deformity of the spine; (2) loss of body height and mobility; (3) feelings of isolation and depression; and (4) gastrointestinal and pulmonary problems. When an osteoporotic compression fracture occurs in a vertebra, there is a 40% chance that an adjacent vertebra will experience a similar fracture within one year.

In order to diagnose a vertebral compression fracture the spine and neck specialist develops a complete case history, performs a physical examination, and employs imaging technology (x-ray, CAT scan, or MRI) to confirm the presence and severity of the fracture. If a fracture is confirmed, the specialist will usually recommend a conservative course of treatment including rest, over-the-counter and prescription pain medication, and bracing to limit spinal movement. In those cases where the individual is experiencing severe pain, the back and neck specialist may undertake a minimally invasive vertebroplasty or kyphoplasty procedure.

If a vertebroplasty is selected the patient receives a local anesthetic and intravenous sedation. The specialist then uses a fluoroscope to place a trocar (large bore needle) into the collapsed vertebra. Once proper needle placement has been achieved, bone cement (polymethylmethacrylate) is injected under pressure into the vertebra to stabilize the fracture and support the spine. The cement hardens quickly, preventing the fracture from collapsing further while it heals. The procedure, which is usually performed on an outpatient basis, takes less than two hours.

If the kyphoplasty procedure (aka Balloon Assisted Vertebroplasty) is selected, the specialist inserts two fluoroscopically guided needles, each containing a deflated balloon, into the vertebra. The balloons are then inflated to increase the height of the vertebra. After the balloons are deflated and removed, bone cement is inserted into the space created by the balloons. Patients usually experience immediate pain relief with either procedure. Complications following vertebroplasty or kyphoplasty are extremely rare. However, there is a very slight risk that the cement will leak, causing pressure on the spinal nerves. In addition, numbness, tingling and infection at the injection site have infrequently been reported.

In some instances, the patient’s intractable pain and imaging studies showing a severe fracture may indicate that open surgery is necessary. In this case, the back and neck specialist may elect to fuse the vertebrae and/or insert spinal instrumentation (plates, rods, hooks, pedicle screws, or cages) to stabilize the spine.

Patients with any one of the following should not undergo a vertebroplasty or kyphoplasty:

  • There has been a greater than 80 percent collapse of the vertebra
  • Osteomyelitis or discitis is present in the vertebra
  • The compression fracture has been present for more than one year
  • There is spinal curvature (scoliosis or kyphosis) that is due to causes other than osteoporosis
  • There is spinal stenosis or herniated discs with nerve or spinal cord compression and loss of neurological function not associated with the compression fracture
  • The patient has coagulopathy (a disease or condition affecting the blood’s ability to coagulate)
  • There has been significant compromise of the spinal canal caused by an impeding bone fragment or tumor

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