Intraoperative neurophysiological monitoring (IONM) is an essential tool in spine surgery, allowing real-time assessment of the functional integrity of neural structures, including the spinal cord, nerve roots, and peripheral nerves. It plays a crucial role in reducing the risk of neurological injury and improving surgical outcomes.
Different neurophysiological modalities are used depending on the type of spine surgery and the structures at risk. These include:
IONM is beneficial in various spinal procedures, including:
—- Neuromonitoring in minimally invasive spine surgery (MISS) provides real-time feedback to surgeons and enhances surgical precision for improved patient safety. Since the 1970s, established techniques like somatosensory evoked potentials, motor evoked potentials, and electromyography have been integrated into spine surgeries, significantly reducing the risk of neurological complications. These neuromonitoring modalities have been crucial, particularly in complex procedures with limited direct visualization. Refinements in these techniques have led to greater confidence in nerve root safety, contributing to the success of MISS. Despite some debate regarding the routine use of neuromonitoring in noncomplex surgeries, its importance in complex cases is well-documented. Studies have demonstrated high sensitivity and specificity rates for these techniques, with multimodal approaches offering the best outcomes. Advancements in mechanomyography and its potential integration into neuromonitoring protocols highlight the continuous improvement in this field. As MISS continues to evolve, adopting next-generation neuromonitoring systems, including artificial intelligence and machine learning, will play a pivotal role in advancing the efficacy and safety of spine surgeries. 1)
IONM has become a standard of care in complex spine surgery, providing critical intraoperative feedback to reduce the risk of neurological injury. A multimodal approach using SSEPs, MEPs, and EMG offers the most comprehensive protection for neural structures. However, proper interpretation of IONM signals and integration with surgical decision-making are essential for optimal outcomes.
The objective of a systematic literature review was to evaluate if intraoperative neurophysiological monitoring (IONM) can prevent neurological injury during spinal operative surgical procedures.
IONM seems to have presumable positive effects in identifying neurological deficits. However, the role of IONM in the decrease of new neurological deficits remains unclear.
Using the Preferred Reporting Items for Systematic Reviews and MetaAnalyses (PRISMA) guidelines for systematic reviews and Meta-analysis, Daniel et al., from São Paulo, Brazil, reviewed clinical comparative study who evaluate the rate of new neurological events in patients who had a spinal surgery with and without IONM. Studies were then classified according to their level of evidence. Methodological quality was assessed according to methodological index for non-randomized studies instrument.
Six studies were evaluated comparing neurological events with and without IONM use by the random effects model. There was a great statistical heterogeneity. The pooled odds ratio (OR) was 0.72 {0.71; 1.79}, P = 0.4584. A specific analysis was done for two studies reporting the results of IONM for spinal surgery of intramedullary lesions. The OR was 0.1993 (0.0384; 1.0350), P = 0.0550.
IONM did not result into fewer neurological events with the obtained evidence of the included studies. For intramedullary lesions, there was a trend to fewer neurological events in patients who underwent surgery with IONM. Further prospective randomized studies are necessary to clarify the indications of IONM in spinal surgery 2).