The spine and spinal cord
All the functions and senses of the body are controlled by the central nervous system (CNS). This system is made up of the brain, spinal cord, and a network of peripheral nerves that spread throughout the body from the spinal cord.
The spinal cord extends from the base of the brain, to down inside the bones of the backbone, which is also known as the spine or the spinal column. The spinal cord does not extend the full length of the spinal column, but ends in the small of the back (the lumbar area).
Just as the brain is surrounded and protected by the skull, the spinal cord is surrounded and protected by the backbone. The backbone is made up of bones called vertebrae. The nerves spread out from the spinal cord, between the vertebrae.
There are 26 vertebrae in the spine:
- 7 cervical (neck)
- 12 thoracic (chest area)
- 5 lumbar (lower back)
- the sacrum (pelvic area) and the coccyx (tail bone).
The sacrum and the coccyx are made up of a number of bones that have been joined, or fused together. There are five in the sacrum and four in the coccyx. The nerves spread out from the spinal cord, between the vertebrae.
Also surrounding and protecting the brain and spinal cord are the meninges (membranes that cover the brain and spinal cord), and cerebrospinal fluid (CSF). The meninges are made up of three different layers: dura mater (outer layer), arachnoid mater (middle) and pia mater (inner).
The spinal cord provides communication between the brain and the rest of the body. Nerve impulses can travel up or down the spinal cord. For example, if we want to pick something up, the brain sends an impulse down the spinal cord and along the nerves that control the functions of the hand. If the object we pick up is soft to touch, an impulse travels up the spinal cord to the brain to tell us that it has a pleasant feeling. These are known as motor and sensory impulses.
Spinal cord tumours
Cells within the CNS normally grow in an orderly and controlled way, but if for some reason this order is disrupted, the cells continue to divide and form a lump or tumour.
A tumour may be either benign or malignant. Although a benign tumour can continue to grow, the cells do not spread from the original site. In a malignant tumour, the cells can invade and destroy surrounding tissue and may spread to other parts of the CNS.
Tumours affecting the CNS are fairly rare. Just over 5000 new tumours are diagnosed each year in the UK. Many of these are malignant.
Intramedullary tumours are located within the nerves of the spinal cord. There are several different types of cancer of the spinal cord, but the most common are astrocytomas and ependymomas.
Intradural extramedullary tumours start inside the coverings of the spinal cord, but outside the cord itself. Meningiomas and nerve-sheath tumours, such as schwannomas, are the most common types of intradural extramedullary spinal tumour.
Extradural spinal tumours
Some tumours start in the bones of the spine (primary bone tumours). There are several different types of primary bone tumours. Benign tumours include chordomas and osteomas. Malignant tumours include osteosarcomas, chondrosarcomas and fibrosarcomas.
Some cancers can spread into the bones of the spine from elsewhere in the body, and are known as secondary bone cancers. The most common primary cancers to spread to the bones of the spine include lung, breast, myeloma, lymphoma and prostate cancer. This information does not cover secondary cancer of the spine.
Causes of spinal cord tumours
The cause of tumours that start in the spinal cord or the membranes (meninges) covering the spinal cord is unknown. Research is being carried out into possible causes.
Signs and symptoms
These depend on the position of the tumour in the spinal cord. Spinal tumours often cause symptoms by pressing on the spinal nerves. Common symptoms include back and neck pain, numbness, and tingling and weakness in either the arms or legs, or both.
Other symptoms can include clumsiness, and difficulty in walking. Tumours in the lower part of the spinal cord may cause loss of control of the bladder and bowel (incontinence).
Tests and investigations
So that your doctors can plan your treatment, they need to find out as much as possible about the type, position and size of the tumour, so you may have a number of tests and investigations.
CT (computerised tomography) scan A CT scan takes a series of x-rays which build up a three-dimensional picture of the inside of the body. The scan is painless but takes from 10–30 minutes. CT scans use a small amount of radiation, which will be very unlikely to harm you and will not harm anyone you come into contact with. You will be asked not to eat or drink for at least four hours before the scan. A CT scan may be used to identify exactly where the tumour is or to check for any spread of the cancer.
Most people who have a CT scan are given a drink or injection to allow particular areas to be seen more clearly. This may make you feel hot all over. Before having the injection or drink, it is important to tell the person doing this test if you are allergic to iodine or have asthma.
MRI (magnetic resonance imaging) scan This test is similar to a CT scan, but uses magnetism instead of x-rays to build up a detailed picture of areas of your body. During the scan you will be asked to lie very still on the couch inside a long tube for about 30 minutes. It is painless but can be uncomfortable, and some people feel a bit claustrophobic during the scan. It is also noisy, but you will be given earplugs or headphones.
Some people are given an injection of dye into a vein in the arm, but this usually does not cause any discomfort.
Treatment
The treatment for a spinal tumour depends on a number of things, including your age, general health, and the position, size and type of tumour. The results of your tests will enable your doctor to decide on the best form of treatment for you. There are some risks associated with treatment to the spine and your doctor will discuss these with you. The main treatments used are surgery, radiotherapy and steroids.
Your treatment will usually be planned by a team of specialists known as a multidisciplinary team (MDT). The team will usually include a doctor who operates on the brain (neurosurgeon), a doctor who specialises in treating illnesses of the brain (neurologist), a specialist nurse and possibly other health professionals, such as a physiotherapist or a dietitian.
Consent
Before you have any treatment, your doctor will give you full information about what the treatment involves and explain the aims of the treatment to you. They will usually ask you to sign a form saying that you give your permission (consent) for the hospital staff to give you the treatment. No medical treatment can be given without your consent.
Benefits and disadvantages of treatment
Treatment can be given for different reasons and the potential benefits will vary depending upon the individual situation. If you have been offered treatment that aims to cure your cancer, deciding whether to have the treatment may not be difficult. However, if a cure is not possible and the treatment is to control the cancer for a period of time, it may be more difficult to decide whether to go ahead.
If you feel that you can’t make a decision about the treatment when it is first explained to you, you can always ask for more time to decide.
You are free to choose not to have the treatment and the staff can explain what may happen if you do not have it. You don’t have to give a reason for not wanting to have treatment, but it can be helpful to let the staff know your concerns so that they can give you the best advice.
The main treatments used are surgery, radiotherapy and steroids.
Surgery
The aim of the surgery is to remove the tumour without weakening the spine. Sometimes it is possible to remove spinal cord tumours completely, especially if the tumour is on the outer part of the spinal cord. If the tumour cannot be removed completely, it is often possible to remove part of it. This can help to slow down the progress of the cancer.
A surgical technique called a decompressive laminectomy is sometimes performed to relieve pressure within the spinal canal. Parts of several vertebrae, and some of the tumour, are removed. As well as relieving pressure, this enables samples of cells from the tumour to be taken (biopsy) to be taken, to find out which type of tumour it is.
Radiotherapy
Radiotherapy uses high-energy rays to destroy the cancer cells, while doing as little harm as possible to normal cells. It is usually given by directing radiotherapy rays at the tumour from outside the body – known as external radiotherapy. It is used to treat spinal tumours that have not been completely removed with surgery, or if the tumour comes back after initial treatment. Radiotherapy is also sometimes used to relieve symptoms, such as pain.
Steroids
Steroids are hormonal substances, naturally produced in the body by the reproductive organs, and the adrenal glands above the kidney. Steroids can be given as tablets or by injection, and can reduce the swelling that often surrounds spinal tumours. Although steroids do not treat the tumour itself, they are very useful in improving symptoms and making you feel better. They may be used before or after surgery; or before, during or after radiotherapy.
Chemotherapy
The role of chemotherapy in the treatment of spinal tumours is still unclear. Research is being done to see whether chemotherapy is effective in treating these tumours.
Secondary spinal cord tumours
It is rare for a cancer elsewhere in the body to spread into the spinal cord, but this may occasionally happen. The treatment used in this situation will depend on where in the body the primary cancer started, as secondary tumours respond to the same treatment as the primary they developed from.
Sometimes, when a secondary cancer is affecting the spinal cord, it can put pressure on the spinal cord and nerves, which can affect the function of the nerves. In this situation, treatment needs to be given as soon as possible, and usually includes radiotherapy and steroids (or occasionally surgery). The aim of the treatment is to shrink the tumour and to relieve pressure on the nerves. Once the pressure is relieved, further treatment may be needed. This depends on the site of the primary tumour that the secondary came from.
Clinical trials
New treatments for spinal cord tumours are being researched all the time, and you might be invited by your doctor to take part in a clinical trial to compare a new treatment against the best available standard treatment. Your doctor must discuss the treatment with you, and have your informed consent before entering you into any clinical trial.
Via: http://www.cancerbackup.org.uk
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