Understanding neuromonitoring during surgery.

What is neuromonitoring?

Your brain, spinal cord and nerves carry the signals that control movement and feeling. During some operations, these structures lie close to where the surgeon is working. Intra-operative neuromonitoring (IONM) checks how well these signals are travelling while the operation is under way, so the surgical team can respond quickly if something changes.

When is it used?

• Brain (cranial) surgery — operations near areas or nerves that control movement, feeling, hearing or the face.
• Spine surgery — operations on or near the spinal cord and nerve roots, including fusion surgery where screws and implants are placed close to nerves.
• Orthopaedic surgery — some bone and joint operations close to major nerves.
• Ear, nose and throat (ENT) surgery — for example, operations on the thyroid, ear or salivary glands, near the nerves that control the voice or the face.

What happens during monitoring?

1. After you are asleep under anaesthesia, small sensors (electrodes) are placed on your skin or scalp, or in nearby muscles.
2. Small electrical signals are sent along the nerves, and the responses are recorded and shown on the monitoring system’s screen. You do not feel this, because you are under anaesthesia.
3. A trained specialist watches the signals throughout the operation and alerts the surgeon if they change, so the surgeon can adjust what they are doing.
4. The sensors are removed at the end of the operation.

Monitoring does not replace the surgeon’s skill and judgement, and it cannot prevent every complication. It gives the team more information while they operate.

After the operation

Some people notice small marks or mild soreness where the sensors were placed. These usually fade within a few days. Tell your care team about anything that worries you.

Questions to ask your surgical team

• Will neuromonitoring be used during my operation, and why?
• Who will watch the signals during surgery?
• Is there anything about my health or my medicines that the team should know beforehand?
• What are the risks and benefits in my case?