Temporal occipital parietal disconnection
This page explains about temporal occipital parietal disconnection and what to expect when your child comes to Great Ormond Street Hospital (GOSH) to have this procedure.
You should read this page in conjunction with our Welcome to the Children's Epilepsy Surgery Service leaflet which explains about the epilepsy surgery programme at GOSH.
What is a temporal occipital parietal disconnection?
A temporo-occipito-parietal disconnection removes the front part of the temporal lobe and disconnects the occipital and parietal lobes on the affected side of the brain, leaving the frontal lobe intact.
Why might my child need this operation?
If your child has focal epilepsy, the seizures start in one area of the brain (focus). Seizures can start in any of the lobes of the brain. A temporo-occipito-parietal disconnection will disconnect the lobes where the seizures have been shown to start, so this should reduce or stop the seizures completely.
It is possible that your child’s focal seizures could become generalised, affecting all the brain. This is called ‘secondary generalisation’ or ‘evolution to bilateral convulsive seizure’. If the operation removes the focus of the seizures and the seizures stop totally, this reduces the risk of secondary generalisation occurring.
However, if your child has seizures after the operation, he or she is still at risk of secondary generalisation.
How do the doctors decide if my child needs this operation?
Your child will previously have had a series of tests and investigations to see where in the brain the seizures are starting and whether these parts of the brain are needed for important functions. All these results are discussed at the multi-disciplinary team epilepsy surgery meeting. The team will decide if surgery is an option.
You will then be able to discuss these results with the team at an outpatient appointment at the epilepsy surgery clinic and come to a decision about the operation. We will send you a letter following your epilepsy surgery clinic appointment summarising the benefits and risks of surgery for your child.
What are the risks of the operation?
Healthy children usually cope well with the anaesthetic, but the risk increases if your child has other problems. Any surgery carries a small risk of infection or bleeding. There is a small chance that your child will suffer some damage to his or her brain that could result in weakness down one side of the body.
Your child’s brain abnormality may mean that they are not able to see to one side. If they have normal vision before surgery then the surgery will reduce their visual field looking to one side and they may not see objects coming from this side. This will not improve after surgery but most children learn to adapt to this very well.
In general, there is a five per cent risk of a complication, which may mean that your child could have to stay in hospital longer than expected.
What should I expect from this operation?
The doctors will explain the risks and benefits of the operation and the chance of improvement in seizure control to you in more detail before you make a decision.
Generally, there is a 40 to 60 per cent chance that this surgery will cure your child’s seizures. This figure depends mainly on the results of the tests your child had to decide whether an operation was suitable. As this information is written in general terms, the doctor will confirm the likelihood of success for your own child. This will be noted in a letter to you following your attendance at epilepsy surgery clinic.
Are there any alternatives to this operation?
The doctors could continue trying to control your child’s seizures with combinations of drugs. However, although there are new drugs available all the time, people who have not responded to them early, have a smaller chance of responding with each new drug tried. This means that there is only a small chance of drugs controlling your child’s seizures long term.
If the ketogenic diet is suitable for your child, your doctor will have discussed this with you. Vagus Nerve Stimulation (VNS) therapy or corpus callosotomy may also be an option, this may be discussed with you by your consultant or by the team at your epilepsy surgery clinic appointment.
What happens before the operation?
Before admission, we will ask you to arrange a blood test with your family doctor (GP) to ensure your child is fit for surgery.
You will need to come to Koala Ward the day before the operation. This is to make sure that your child is well enough to have the operation. A doctor will examine your child and may take a repeat blood sample to check that his or her blood levels are fine. The doctors will explain about the surgery in more detail, discuss any worries you may have and ask your permission for the operation, by signing a consent form. Another doctor will also visit you to explain about the anaesthetic.
Occasionally, some children need neuropsychology testing and a further scan before the operation, but we will let you know if this is likely before you come into hospital. If your child has any medical problems, for instance, allergies, please tell the doctors about these.
If your child has had any infectious diseases like chicken pox or head lice recently, please tell the doctors. The evening or the morning before the operation, your child will need to have a bath and a hair wash.
What does the operation involve?
Your child will have this operation under a general anaesthetic. This means that your child will not feel any pain during the operation, which will last between four and five hours. Your child’s head will not be shaved completely, just a line where the doctors will make the incision (cut). This will be done while your child is under the anaesthetic. The doctors will make one incision on your child’s head.
They will have to open a piece of your child’s skull so that they can operate on the brain, but they will replace and fix it after surgery. After the operation, the doctors will close up your child’s skin and fix it with stitches.
What happens after the operation?
A member of staff will bring your child back to Koala Ward after the operation, when he or she has recovered from the anaesthetic. When your child comes back from the operating theatre they will have a head bandage on. Your child may also have a drain coming out from the wound, which looks like a clear, plastic tube. This is removed after 24 hours. At the end of the day, the doctors will visit you to talk about the operation.
Your child may feel sick after the operation, but the doctors will give him or her medicines to reduce this. The sickness should pass within a couple of days. Children usually come back from theatre with an intravenous infusion (drip) to replace their body fluids when they are unable to drink. The nurses will monitor your child closely for the first few days after the operation to make sure he or she is recovering well.
Your child’s face may be a little bruised and swollen after the operation. This may get worse over the first two to three days but will then start to improve. If your child is in any pain, the doctors and nurses will give him or her medicines to reduce this. Your child may also develop a high temperature after the operation, but this is usual and does not tend to be due to an infection. The doctors may carry out some tests to make sure.
Over the next few days your child will be able to start moving around. Older children often take longer to recover. Your child is likely to be in hospital for between four to six days. He or she will be able to gradually return to normal day-today life and full activity over the next two to three months. Your child should stay away from school for about four weeks after the operation. Your doctor/nurse will give you more specific information before you leave hospital.
When you and your child leave hospital, we will arrange for you to come to outpatient appointments at regular intervals. These will usually be six weeks, six months and a year after the operation. We will check that your child is recovering well from the operation and that his or her seizures are under control. It is unlikely that your child’s drugs would be changed for at least six months.