Intraoperative neuromonitoring reduces the risk of postoperative neurological impairments
Access for doctors
The aim of surgical interventions is to completely resect diseased tissue or to repair and stabilise it without affecting healthy tissue too much. Particularly in the case of interventions in the vicinity of functionally relevant nerves and neurological structures, this is sometimes very difficult and often cannot be adequately achieved by visual inspection alone. This is where intraoperative neuromonitoring comes into effect.
Tool for nerve-sparing surgery
Intraoperative neuromonitoring provides surgeons with a tool that efficiently supports them during nerve-sparing surgery. The main goal of neuromonitoring is to monitor and maintain the patient’s neurophysiological functions. Neuromonitoring therefore also makes it possible to avoid consequential damage and postoperative complications.[1] [2] [3] Patients, surgeons and hospitals benefit equally from fewer postoperative complications.
The term intraoperative neuromonitoring (IONM) refers to the intraoperative monitoring of neurophysiological functions of the central and peripheral nervous system. The surgeons are thus able to localise and identify nerves and trace their course. They no longer have to rely solely on visual inspection. Depending on the surgical case, EMG (electromyography) and evoked potentials (SEP, AEP, MEP, EEG and VEP) can be used for continuous (or intermittent) monitoring as well as localisation of the nerves.
Technical implementation for neuromonitoring
Depending on the application field, neuromonitoring is carried out using devices that enable electrical stimulation via probes and electrodes on the nerve or tissue and visualise the recorded signals via electrodes with the option to make them audible, too. The systems for neuromonitoring offer acoustic and visual alarm functions that inform the surgical team about critical changes in the signals. In the event of a critical signal change (defined decrease in amplitude, changes in latency, absence of specific curves etc.)[4] [5] the tissue resection can be stopped in good time and the surgical procedure can be adapted accordingly. Correct anaesthetic management is essential for neuromonitoring, as inappropriate anaesthesia >> can lead to the absence of the necessary signals or to misleading signals.
The documentation and storage functions are also of great benefit, facilitating postoperative analysis and potential legal argumentation. Neuromonitoring can additionally be used for postoperative assessment of the patients and their ability and duration of regeneration.
References
1. Sala, F. et al. Motor Evoked Potential Monitoring Improves Outcome after Surgery for Intramedullary Spinal Cord Tumors: A Historical Control Study: Neurosurgery 58, 1129–1143 (2006).
2. Martin, W. H. & Stecker, M. M. ASNM Position Statement: Intraoperative Monitoring of Auditory Evoked Potentials. J. Clin. Monit. Comput. 22, 75–85 (2008).
3. Mangano, A. et al. Evidence-based analysis on the clinical impact of intraoperative neuromonitoring in throid surgery: State of the art and future perspectives. Surg Technol Int 25, 91–6 (2014).
4. Deletis, V. & Sala, F. Corticospinal tract monitoring with D- and I- waves from the spinal cord and muscle MEPs from limb muscles. in Intraoperative Monitoring of Neural Function – Handbook of Clinical Neurophysiology 8, 235–251 (2008).
5. Angeletti, F., Musholt, P. B. & Musholt, T. J. Continuous Intraoperative Neuromonitoring in Thyroid Surgery. Surg Technol Int 27, 79–85 (2015).