Neurophysiological monitoring during surgical procedures

The application of intraoperative neurophysiological monitoring (IONM) is gaining more and more importance in daily clinical practice. The use of IONM allows the localization of neural structures and to control functioning of the peripheral and central nervous systems in anesthetized patients. This enables surgeons to identify and to protect neural structures and cerebral areas. The use of IONM also enables anesthesiologists to adjust anesthesia and cardiopulmonary therapy to the individual needs of the patient. Thereby, it may be possible to reduce the incidence of postoperative delirium and the incidence of postoperative cognitive deficits. To exploit the full potential anesthesiologists and surgeons must be able to use the methods of IONM safely and understand the results; therefore, basic knowledge of the technology, options and limitations of IONM is necessary. It is also important to be aware of the influence of anesthetics on the methods of IONM. Total intravenous anesthesia (TIVA) is the anesthetic method of choice, because it has only minimal influence on IONM methods. It is important to avoid bolus injections of hypnotics to achieve stable blood concentrations. Long- acting neuromuscular blocking agents should be avoided, because they disturb the signals of electromyography and motor-evoked potentials. By using IONM anesthesiologists and surgeons can identify changes in the function of the peripheral and central nervous system prior to irreversible damage.