Spinal cord monitoring during your child’s spinal surgery

Your child has been referred for spinal surgery. This resource will give you some information about the monitoring your child’s surgeon has asked us to perform during surgery.

What is spinal cord monitoring?

Monitoring the spinal cord helps the surgeon to reduce the risk of nerve damage during surgery, but cannot eliminate these risks entirely. Your surgeon will have already discussed the risks of surgery with you.

Monitoring involves sending tiny electrical messages up and down the spinal cord throughout the surgery to ensure it is responding properly.

On the day of your child’s operation

On the day of the surgery your child will be taken to theatre and into the anaesthetic room. Once they are asleep we will position very fine needles which contain electrodes into their arms, legs and head.

If the area of the spine to be operated on involves bladder or bowel function then additional needle electrodes are inserted. To monitor bowel function these will be near the opening of the bottom (where poo leaves the body). To monitor bladder function in girls we may also insert needle electrodes into the area near the urethra (the opening of the tube where pee leaves the body) and in boys we may also insert needle electrodes into the penis.

We use a special type of tape to ensure the needles stay in place during the operation. The needles are for single use only and are disposed of after each surgery.

During surgery

The following are the types of monitoring that we usually carry out during surgery:

Sensory Evoked Potentials

Sensory Evoked Potentials (SEP) test the nerve pathways from the arms and legs through the spinal cord to the brain. The messages are sent from nerves in the arms and feet and recorded at the knee, shoulder and head using small needle electrodes. We may also be able to record the response from the spinal cord with a spinal electrode which is inserted by the surgeon into the space next to the spinal cord. The SEP tests are performed at short intervals throughout the surgery. If there are any significant changes we inform the surgeon.

Motor Evoked Potentials

Motor Evoked Potentials (MEP) test the pathways from the brain to selected muscles in the arms, legs or feet. We do this by sending a message to the brain with electrical pulses sent through small needles placed just under the skin on the head and recording from needles placed in to muscles in the arms, legs or feet. This test is performed at short intervals throughout surgery. If there are any significant changes we inform the surgeon.

Free run EMG

A free run electromyography (EMG) identifies nerve structures or nerve roots near the spinal cord which may be irritated by the surgeon during the operation. We do this by recording the muscle activity in the arms, legs, pee tube opening (urethra) and bottom (anus).

Stimulated EMG

A stimulated electromyography (EMG) is recorded when the surgeon uses a specially designed probe to stimulate structures to identify the nerve fibres or nerve roots. These are then avoided to minimise damage.

After the operation

All the electrodes will be removed before your child is woken up .

Are there any additional risks by having monitoring during surgery?

Some minor bruising may occur at the needle sites where the electrodes have been inserted.

If your child has an implanted pacemaker or defibrillator then the electrical stimulation may interfere with the function, however their heart will be monitored throughout surgery.

During the MEP the muscles that contract during stimulation have a 1 in 150 risk of injury as the result of a tongue bite or lip injury. While we do fit every child with a mouth guard to minimize this risk, it is still possible for an mouth injury to occur. This is because your child may be positioned face down during surgery, which causes the tongue to protrude.

Please inform the anaesthetist or surgeon if your child has epilepsy or has had epileptic seizures in the past. There is a 1 in 3,000 chance of the stimulus triggering a seizure during the surgery even if you do not have epilepsy.

As with any procedure we must obtain your consent beforehand. Your child’s surgeon will explain all the risks, benefits and alternatives of the surgery before they ask for your consent. If you are unsure about any aspect of this procedure, please do not hesitate to ask for more information.