What Is Intraoperative Neuromonitoring (IONM)? A Practical Guide for Surgical Teams

· NJM Medical Editorial Team

How IONM protects nerves, the spinal cord and the brain during surgery — the main modalities, where it is used and what a hospital needs to start a programme.

Every year, surgeons operate closer to delicate neural structures — the facial nerve in skull-base surgery, the recurrent laryngeal nerve in thyroid surgery, motor pathways in spine and brain tumour surgery. Intraoperative neuromonitoring (IONM) gives the surgical team a real-time view of how those structures are functioning while the operation is under way.

How IONM works

IONM records electrical signals from the nervous system and compares them with a baseline taken at the start of surgery. A change in amplitude or latency can warn the team early — often before an injury becomes permanent — so the surgeon can pause, reposition a retractor or change the approach.

The main modalities

  • Free-running and triggered EMG — detects irritation of a motor nerve and helps locate and identify nerves with a stimulation probe.
  • Motor evoked potentials (MEP) — assess the integrity of motor pathways from the cortex through the spinal cord.
  • Somatosensory evoked potentials (SEP) — monitor sensory pathways and are widely used in spine and carotid surgery.
  • Direct cortical and subcortical stimulation — maps eloquent brain areas, such as motor and speech regions, during tumour resection.

Where IONM is used

Typical applications include thyroid and parathyroid surgery, ENT and skull-base surgery, spine surgery, neurosurgery and brain mapping, vascular surgery such as carotid endarterectomy, and rectal surgery. Platforms such as the inomed C2 Xplore combine several of these applications in one device, while systems like the Dr. Langer AVALANCHE® SI 2 offer multimodal monitoring for complex neurosurgical and spinal cases.

What a hospital needs to start

  1. The right system — matched to your case mix: a compact nerve monitor for thyroid and ENT, or a multimodal platform for spine and neurosurgery.
  2. Consumables and electrodes suitable for each procedure.
  3. Trained people — surgeons, anaesthetists and neurophysiology staff who understand how anaesthesia affects signals.
  4. Clear protocols for baselines, alarm criteria and documentation.

How NJM Medical can help

From our base in Giza, NJM Medical helps hospitals in Egypt choose, install and use neuromonitoring systems — including demonstrations in your OR, user training and ongoing clinical support. Contact our team to discuss your procedures.

This article is for general information for healthcare professionals and is not medical advice. Device selection and settings must always follow the manufacturer’s instructions for use and the treating clinician’s judgement.