Intraoperative neurophysiological monitoring during spine surgery: a review

Abstract

<jats:p>Spinal surgery involves a wide spectrum of procedures during which the spinal cord, nerve roots, and key blood vessels are frequently placed at risk for injury. Neuromonitoring provides an opportunity to assess the functional integrity of susceptible neural elements during surgery.</jats:p> <jats:p>The methodology of obtaining and interpreting data from various neuromonitoring modalities—such as somatosensory evoked potentials, motor evoked potentials, spontaneous electromyography, and triggered electromyography—is reviewed in this report. Also discussed are the major benefits and limitations of each modality, as well as the strength of each alone and in combination with other modalities, with regard to its sensitivity, specificity, and overall value as a diagnostic tool. Finally, key clinical recommendations for the interpretation and step-wise decision-making process for intervention are discussed.</jats:p> <jats:p>Multimodality neuromonitoring relies on the strengths of different types of neurophysiological modalities to maximize the diagnostic efficacy in regard to sensitivity and specificity in the detection of impending neural injury. Thorough knowledge of the benefits and limitations of each modality helps in optimizing the diagnostic value of intraoperative monitoring during spinal procedures. As many spinal surgeries continue to evolve along a pathway of minimal invasiveness, it is quite likely that the value of neuromonitoring will only continue to become more prominent.</jats:p>

A socioeconomic analysis of intraoperative neurophysiological monitoring during spine surgery: national use, regional variation, and patient outcomes

“…We examined use of intraoperative neurophysiological monitoring (IONM) during spine surgery, which commonly includes measuring and monitoring somatosensory evoked potentials, motor evoked potentials, electromyographic recordings, or any combination, 5,12 during spine surgery.…”

A CT-based study investigating the relationship between pedicle screw placement and stimulation threshold of compound muscle action potentials measured by intraoperative neurophysiological monitoring

“…Additionally 24 % (16 screws) of thoracic and 15 % (21 screws) of lumbar screws caused cortical breach in either horizontal, vertical or both directions, but had stimulation thresholds above 10 mA (false negatives, Table 2). Split into three regions (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30) and [30 mA, Fig. 2) the stimulation threshold range of 10-20 mA hosts both, the majority of correctly placed and the majority (67 %) of misplaced thoracic screws.…”

“…EMG bipolar electrodes (Xomed TM ) were placed on muscles innervated by the correspondent myotomal root (surface electrodes on rectus abdominis muscle for thoracic screws, needle electrodes on quadriceps, tibialis anterior and gastrocnemius for lower limb roots) [12]. EMG signal was acquired TM using an Eclipse system (Axon TM ), bandpassed filtered between 10 and 1,000 Hz and visualized usually at a 1 cm/mV scale.…”

Editorial: Neuromonitoring

“…Several published reports from other authors have reported the use of intraoperative spinal cord monitoring as a meth od to identify neural irritation or injury at a time when the surgeon can take steps to reduce or reverse it. [1][2][3][4] The low complication rate in this series may be a re flection of the expertise of the authors in treating cervical spine disease or may result from the possibility that all complications were not captured in this retrospective re view. It is important to point out that in hospitals in which surgical volume is not comparable to the University of Iowa Hospitals & Clinics, the risk of neurological deficit when not using intraoperative spinal cord monitoring may be greater.…”