Anesthetic considerations during intraoperative neurophysiological monitoring in spine surgery

Objective We conducted an overview of the intraoperative neurophysiological monitoring (IONM) modalities in spine surgeries and effects of anesthesia and physiological factors on these modalities. Background The development of IONM minimizes iatrogenic neurological complications. All anesthetic agents impact on the modalities of IONM. Materials and methods Medline, articles in Medscape, ScienceDirect, and PubMed were searched. The search was performed in January 2016 and included all articles with no language restriction. The initial search presented 50 articles. The articles studied the types of IONM modalities and effects of anesthesia on these modalities. Data from each study were independently abstracted to capture information on study characteristics, interventions, and quantitative results reported for each outcome of interest. Significant data were collected and thus a structured review was performed. Results A close working relationship of the monitoring team, the anesthesiologist, and the surgeon is a key to the successful conduct and interpretation of IONM, prevention of complications of spinal surgeries, and early detection of these complications. On the basis of the monitoring modalities involved, the basic anesthetic constraints can be identified. Conclusion Using IONM such as somatosensory and motor-evoked potentials has become common to minimize neural risk and to improve intraoperative decision making for any spine surgery. IONM is affected by the choice of the different anesthetic agents and skeletal muscle relaxants, because anesthetic agents have effects on neural synaptic and skeletal muscle relaxants have effects on neuromuscular junctions.