Surgery for brain and spinal cord tumours

Surgery is a medical procedure to examine, remove or repair tissue. Surgery, as a treatment for cancer, means removing the tumour or cancerous tissue from your body.

Surgery is usually used to treat brain and spinal cord tumours. Surgery for brain and spinal cord tumours is called neurosurgery. A surgeon who specializes in treating these tumours with surgery is called a neurosurgeon.

Before you are offered this treatment, you are evaluated very carefully with a neurological examination. This exam looks for any changes to functions such as reflexes, speech, hearing, vision, thinking, movement and feeling.

As well, the neurosurgeon needs to decide whether the tumour can be removed with surgery. Imaging tests such as CT scans and MRIs may show that the tumour is in an area of the brain or spinal cord that is too difficult to reach or where there are important functions that can be damaged by surgery. Tumours that can’t be removed are called inoperable.

Surgery may be done for different reasons. You may have surgery to:

• completely remove the tumour
• remove as much of the tumour as possible (called debulking) before other treatments
• remove a sample of the tumour (biopsy) to determine the type of tumour
• insert a tube (shunt) to drain cerebrospinal fluid (CSF) to lessen pressure on the brain
• place a device called an Ommaya reservoir to remove CSF or to give chemotherapy
• reduce pain or ease symptoms (palliative surgery)

The type of surgery you have depends mainly on where the tumour is in the brain and how big it is. When planning surgery, your healthcare team will also consider other factors, such as your age, neurological function (how the different parts of the nervous system are working) and overall health.

There are different types of surgery used to treat brain and spinal cord tumours. You may also have other treatments after surgery.

During surgery on the brain, it is important to avoid damage to the areas of the brain that are responsible for movement, language, hearing and eyesight. Before surgery, imaging tests show where the tumour is and if it is in an area that controls these functions. The goal of surgery is to remove as much of the tumour as possible while causing as little damage as possible.

Brain mapping uses a mild electrical current on the surface of the brain to detemine the function of that part of the brain. The information is then mapped so that the neurosurgeon can avoid these areas when removing the tumour.

The brain tissue itself does not have any nerves, so brain mapping is painless. You will be under a general anesthetic when the scalp is being cut and the bone flap is removed. When the neurosurgeon is ready to start mapping the tumour, you may or may not be woken up.

Awake brain mapping is when you are awake during surgery so you can talk to the neurosurgeon. They will ask you to follow instructions such as counting, reading or answering questions while they are using the electrical current. The surgical team will make sure you are answering questions properly, and that you can do the tasks without any problems or mistakes. If you have problems with the tasks while a certain area is being tested, the brain map will show that these areas must be avoided during surgery.

The electrical current is also used to track the areas around the tumour that are responsible for movement and reflexes. When the current is applied, the neurosurgeon looks for any movement of your body. You will also be asked about any sensations that you may be feeling, such as tingling or numbness.

When the mapping is finished, you will be given a general anesthetic again and the surgeon will continue the operation to remove the tumour, using the mapped areas as a guide.

Asleep brain mapping is done without waking you up during the surgery. It is mostly used to map which areas of your body move when the electrical current is applied. Once the mapping is done, the operation is done using the mapped areas as a guide.

A craniotomy is surgery that opens the skull to remove a brain tumour. The goal of surgery is to remove as much of the tumour as possible without destroying important brain tissue or affecting brain functions. You will be under general anesthesia, but you may be woken up for part of the surgery if the neurosurgeon needs to do brain mapping.

Before surgery, your healthcare team may shave the part of your head where the surgery is going to be done. During surgery, the neurosurgeon makes a cut (incision) in the scalp. A piece of the skull is removed with a medical drill to expose the area where the neurosurgeon will be operating. This piece of skull is called a bone flap.

The neurosurgeon then makes a cut in the membranes that cover the brain. They may have to cut into the brain tissues to reach the tumour and remove it.

The neurosurgeon removes as much of the tumour as possible. The tumour may be removed with:

• a scalpel or scissors
• suction

A special ultrasound machine is sometimes used to break up the tumour and make it easier to remove. The neurosurgeon may also use a special operating microscope that helps to identify the edges of the tumour.

Image-guided surgery may be used for some brain tumours. Images are repeatedly taken with an MRI or a CT scan during the operation to show the location of the tumour and the neurosurgeon’s instruments.

When all or as much of the tumour as possible has been removed, the brain’s membranes are tightly stitched together, the piece of skull is replaced using small screws and plates, and the scalp is closed with stitches or staples. If the brain is very swollen after surgery, the piece of skull may be replaced later when the swelling has gone down.

Healing after a crainotomy usually takes several weeks.

Brain tumours can block the flow of cerebrospinal fluid (CSF) around the brain, causing a buildup of CSF that leads to increased pressure in the skull. This is called increased intracranial pressure (ICP) or hydrocephalus. ICP can cause headaches, vomiting, irritability and seizures. Surgery to remove the tumour can help with this, but there are also other ways to drain away excess CSF and lower pressure in the skull.

An external ventricular drain (EVD) is a thin tube inserted through the skin and skull into a fluid-filled chamber (ventricle) in the brain. An EVD allows CSF to drain from the brain into a collection system or bag outside the body. It is sometimes used to treat a buildup of CSF before or during surgery to remove a brain tumour. An EVD can’t be left in place permanently so it is replaced with a shunt if drainage is still needed.

A shunt is a narrow, soft, flexible piece of tubing. It has a valve system that regulates the pressure of the CSF and prevents fluid from flowing back into the ventricles. Many shunts have reservoirs that can be used to remove CSF samples. During surgery, the shunt is placed in a ventricle of the brain that is filled with CSF. It runs from the ventricle to the scalp, then under the skin of the neck and chest and into the abdominal cavity (not the stomach). The CSF that drains into the abdominal cavity is reabsorbed into the bloodstream. A shunt can be temporary or permanent. It can be placed before or after surgery to remove the tumour.

An endoscopic third ventriculostomy (ETV) is a procedure in which the surgeon makes an opening and places a tube in the third ventricle of the brain to allow CSF to flow around an obstruction. The surgeon uses an endoscope to navigate within the ventricle and create an internal bypass. An ETV is sometimes used to treat a buildup of CSF in the brain. It can also be used to biopsy or remove tumours within the ventricles of the brain.

Find out more about increased intracranial pressure (ICP).

A laminectomy is surgery to remove a vertebra covering the spinal cord in order to remove a spinal tumour.

Before surgery, you may have a procedure called embolization. This is a procedure that blocks the flow of blood to the spinal tumour if the tumour has a lot of large blood vessels. A catheter is threaded from an artery in your leg to the blood vessels around the spinal tumour. Materials such as metal or plastic beads are placed in these blood vessels to block the blood flow to them. This makes a spinal tumour easier to remove.

During the operation, the neurosurgeon makes a cut in the area of the spine over the tumour and removes the vertebra. If the tumour can’t be reached in this way, the surgery may be done by removing a rib to get to the spinal cord through the chest or from behind the abdomen.

Next, the neurosurgeon makes a cut in the membranes covering the spinal cord to reach the tumour and remove as much of it as possible without causing damage to the nerves of the spinal cord.

The neurosurgeon may use:

• a microsurgical laser, which uses a powerful, narrow beam of light (called a laser beam) to destroy the tumour
• an ultrasonic aspirator system, which produces high-frequency sound waves and suction to break up and remove the tumour

An ultrasound may be done during surgery to accurately show the edges of the tumour and confirm that enough bone has been removed to reach the tumour.

When the tumour has been removed, the membranes are tightly stitched together so that the CSF doesn’t leak out. The muscles along the spine are also sewn back together.

An en bloc resection is a technique in which the neurosurgeon removes a tumour in a single piece. An en bloc resection is used to remove some spinal cord tumours.

During an en bloc resection, all the tissues (including soft tissue, muscle, ligaments and blood vessels) attached to the vertebra and ribs around the tumour are carefully cut apart.

When all the tissues are separated, different amounts of tissue may be removed:

• A marginal en bloc resection removes only the tumour.
• A wide en bloc resection removes the tumour along with a layer of healthy tissue around the tumour.
• A marginal or wide en bloc vertebral body resection removes the entire vertebra. This technique is also called a total en bloc spondylectomy (TES). A TES is performed either through both the back and the abdomen or only through the back (called a posterior-only approach).

Once the tumour is removed, the surgeon rebuilds the vertebra to stabilize the spine.

When part or all of a vertebra is removed, the spine is weakened. The spine must be reinforced or stabilized so it can function properly.

If the vertebrae above and below the removed section are undamaged, the surgeon can stabilize the spine using fixation devices. These are special pins, plates, rods, hooks or distractible cages (implants that replace a vertebra). The surgeon attaches the fixation devices to the bones above and below where the vertebra was removed.

If there is no stable bone that can be used to attach the fixation devices, you will need to wear a brace. You will remain in bed while the brace is made and fitted.

Embolization is a treatment that blocks or slows down the blood going to tissues or an organ. It can be used to block the flow of blood to a tumour so the cancer cells die.

Spinal embolization can be used to treat a spinal cord tumour. A thin, flexible tube (called a catheter) is inserted into an artery in the groin (called the femoral artery). It is moved up through the artery until it reaches the arteries near the spinal tumour. A dye is injected into the catheter and an x-ray (called an angiogram) is taken to find the branches of the artery that are feeding the tumour. The doctor then moves the catheter into the arteries feeding the tumour, and gel sponges or special beads are injected into the arteries to block them. Once the arteries have been blocked, the catheter is removed. When the blood supply is stopped, the spinal tumour will start to shrink and die.

Spinal embolization is also used before surgery to reduce the amount of blood flow so that there is less bleeding from the tumour. This makes the tumour easier and safer to remove.

Side effects of surgery for brain and spinal cord tumours will depend mainly on the type and location of the tumour, any symptoms you had before surgery and your overall health. Tell your healthcare team if you have side effects that you think are from surgery. The sooner you tell them of any problems, the sooner they can suggest ways to help you deal with them.

Surgery for brain and spinal cord tumours may cause these side effects:

• bleeding
• infection of the surgical cut
• pain
• swelling of brain tissue (cerebral edema)
• changes to movement, speech and language, memory, balance and coordination, or emotions
• seizures
• leakage of CSF through the incision
• increased intracranial pressure

Find out more about surgery and side effects of surgery. To make the decisions that are right for you, ask your healthcare team questions about surgery.