Tumors of the spine encompass a wide variety of locations, severity and aggressiveness. They can be either benign or cancerous. They are much less common than the degenerative spinal disorders such as lumbar stenosis, lumbar disc herniation, degenerative disc disease, cervical disc herniation or cervical stenosis. However the effect of these tumors can be devastating. As a result of this, diagnosis and cutting edge medical and surgical treatment are required to obtain the best possible outcome.
SPINAL ANATOMY
Before discussing the different types of tumors that can occur we must have a basic understanding of the anatomy of the spine and the different locations that tumors can arise in. The spinal cord runs through the spinal canal which runs down through the back half of the vertebrae (the bones that make up the spinal column). Individual spinal nerves exit the spinal cord and leave the sides of the spinal column through a set of bony tunnels called the neural foramina. The spinal cord and nerves are wrapped in a membrane called the dura. These structures are bathed in water like fluid called cerebrospinal fluid (CSF)
LOCATIONS OF TUMORS
Tumors can arise in any of the above locations. Depending on where they grow, and how large they are, determines what type of an effect they have. Epidural tumors arise outside of the dura and cause their symptoms by one of two ways. They can grow within the vertebral bones, causing them to weaken and collapse. The deformity that is caused by the collapsed bones can sometimes put pressure on the spinal cord and nerves and cause neurological symptoms including numbness, weakness in the arms and legs, back or neck pain, difficulties with urination (incontinence or inability to urinate), and most significantly, paralysis. These symptoms can also occur in patients who have tumors they grow within the central spinal canal and directly compress the spinal cord without involving the bones.
Intradural tumors are classified into two different categories. Intradural extramedullary tumors grow within the CSF space inside the dura and usually arise off one of the spinal nerves. Sometimes they can grow from the inside of the dura itself. Neurological symptoms are caused by compression of the nerves and spinal cord as the tumor fills the bony canals that these nerves run through, and cause pressure on the spinal cord or nerves.Intradural intramedullary tumors arise from the spinal cord itself and very often grow completely inside the cord, and expand it from within. These tumors can become symptomatic earlier because all tumor growth is causing pressure and possible injury to the spinal cord, even if the spinal canal is not completely filled by the widened spinal cord.
TUMOR TYPES/SYMPTOMS
Metastatic tumors are severe complications of patients who suffer from systemic cancer. They are the most frequently occurring tumors of the bones of the spinal column. Often there is disease in other parts of the body prior to the spine being involved, but this is not always the case. The majority of these tumors are located in the extradural space as discussed above. Metastatic tumors occurring in the intradural extramedullary space are uncommon and intramedullary tumors are rare. The most common symptom of metastatic disease to the spine is pain in the location of the tumor. This can include purely back or neck pain, but can also involve bandlike pain running down the arms or legs or around the chest and abdomen, depending on which nerve roots are involved. As the symptoms progress, weakness, numbness and bowel and bladder control problems will occur. If not treated, permanent paralysis can occur.
Intradural extramedullary tumors make up about two thirds of tumors of the spine. Schwannomas and meningiomas makeup the vast majority of these types of tumors. Relatively rare tumors in this location include ependymoma, dermoid, epidermoid, lipoma, chordoma, lymphoma, melanoma, sarcoma and metastatic carcinoma. The most common symptoms include slow progressive neurological abnormalities. These would include pain, numbness, tingling, weakness, bladder and bowel problems. As in metastatic tumors, pain is usually the main symptom initially. It can go into the arms and legs or wrap around the torso and a belt-like fashion. As the symptoms progress without treatment, weakness, bladder and bowel problems can occur. Those symptoms are usually slowly progressive over months or years, if the tumor bleeds into itself or causes compression of a blood vessel supplying the spinal cord occurs, sudden loss of neurological function is possible.
Intradural intramedullary tumors are the least common spinal tumors. In adults the most common tumor of this type is the ependymoma. This is followed by astrocytoma and hemangioblastoma. Less common tumors include oligodendroglioma, ganglioglioma, glioblastoma multiforme, schwannoma, melanoma, metastatic disease, teratoma, cavernous malformation, dermoid, epidermoid and lipoma. Symptoms of pain, tingling, numbness, weakness, bowel/bladder abnormalities and paralysis are all possible as in other types of spinal tumors.
DIAGNOSIS
After a complete neurological examination and complete medical history is taken, there are a number of diagnostic studies that are useful in determining the particular location of the spinal tumor. The list below is not exhaustive, and not all of these studies are necessary in every situation. This underscores the importance of consultation with a neurosurgeon who is highly experienced in the treatment of these tumors.
Plain x-rays of the cervical, thoracic and/or lumbar spine can be a useful screening test in some situations. They will frequently be abnormal in the case of tumors of the bony spine or metastasis. They are less useful in the case of purely extradural and intradural lesions since only a minority of them will cause bony erosion.
Computed axial tomography (CAT) scans are helpful in determining the degree of bony destruction caused by tumors as well as extension of the tumors outside of the spine. This imaging can also be combined with a myelogram to give information about the degree of spinal cord and nerve compression as well as the location of the spinal tumor if there is no bony involvement.
Magnetic resonance imaging (MRI) is the imaging of choice for all spinal tumors. This allows the entire spinal column to be reviewed in multiple ways including axial, sagittal and coronal reconstructions. It also gives information about involvement of the bony spine and gives the clearest picture of soft tissue involvement both inside and outside the spine. It is the only way to directly image the spinal cord.
TREATMENT
Surgery is the main treatment for most nonmetastatic spinal tumors. Since many of these lesions can be benign (non-cancerous), complete surgical removal can allow a patient to avoid other treatment options such as radiation or chemotherapy. The tumor location within the spine, the spinal level, the extent of the tumor and how much damage to the surrounding bone has been caused will determine the type and extent of surgery necessary to treat the tumor. Very often, there is a role for surgery in metastatic spinal disease as well. This tends to be an important treatment option in patients who have symptomatic spinal cord or nerve compression causing neurological decline or unstable fractures that have been caused by bony collapse because of erosion of the vertebra by the tumor. Since the options are extremely wide ranging, it is beyond the scope of this article. An in-depth discussion with your neurosurgeon for your particular situation is very important.
Radiation therapy is most commonly used in the situation of metastatic tumors. There is a more limited role for radiation in other spine tumors. A small number of spinal cord and spinal nerve tumors are malignant, and these will need radiation therapy as well. In certain situations, if a tumor cannot be safely removed in its entirety, radiation therapy can be considered.
Chemotherapy is usually reserved for patients who have metastatic disease to the spine. There is a minimal role for chemotherapy in most other tumors of the spine unless they are known to be malignant.
SPECIALTY CARE AT THE PIEDMONT SPINE CENTER
Treatment of spinal tumors is a complex, multidisciplinary process. The neurosurgeon is an integral part of this treatment and it is important to have someone who has had significant experience in treating patients with spinal tumors. At the Piedmont Spine Center, we have extensive surgical experience in treating spinal tumors as well as having skilled specialists in radiation oncology and medical oncology to assist patients that need more than just surgical care. We welcome second opinions and feel strongly that sometimes it is worth the mild inconvenience of traveling a bit out of your way to ensure that you obtain the best care possible.
For more information about the Piedmont Hospital Spine Center, visit piedmontspinecenter.org.