Spinal neuromonitoring/ Intra-Operative Neurophysiological Monitoring (IONM) involves assessing function of spinal cord and spinal nerves during spine surgeries. Neuromonitoring involves various modalities to assess different functions of the spinal cord. Various electrodes are placed on patients skin and inside different muscles depending upon area of spinal cord at risk. Electrical stimulations are monitored, either continuously or on stimulation of brain/ specific nerve to assess function of spinal cord/ nerve. A change from baseline (before the surgery starts) recording will be important.
Indication of Spinal Neuromonitoring:
Neuromonitoring is a norm for all spine surgeries in western world. However, it’s especially useful for surgeries carrying high risk of causing spinal cord damage and paralysis.
Spine deformity correction (scoliosis, kyphosis).
Revision spine surgery.
Complex spine reconstruction (spine infection, spinal tumor, spinal fracture).
High risk cervical spine surgery.
Advantages of Spinal Neuromonitoring:
Neuromonitoring assesses function of spinal cord and spinal nerves during the surgery. Any irritation/ damage of these structures will be manifested as a change in neuromonitor recording. This will help spine surgeon to immediately reverse the step which caused these changes and thus prevent any damage to spinal cord/ spinal nerves.
Disadvantages/ Limitations of Spinal Neuromonitoring:
Neuromonitoring is not a full proof science. There are both false negative (spinal cord damage not detected) and false positive (changes in neuromonitoring without actual spinal cord/ nerve damage) signals. A false negative signal will lead to spinal cord damage with resultant problems in spite of using neuromonitoring providing a false sense of security. On the other hand a false positive signal will cause unnecessary panic and will force surgeon to prevent from performing some critical surgical steps causing less satisfactory surgical outcome.
In spite of these limitations, neuromonitoring is a very helpful tool to assess nerve function during complex spine surgeries. In vast majority of the cases, it will serve the purpose of preventing spinal cord damage.