Clinical bottom line
Intraoperative neuromonitoring (IONM) is increasingly utilized during orthopedic spine surgery to reduce the risk of nerve injury, including both central neural structures and peripheral nerves related to patient positioning. Current evidence suggests that IONM can provide real-time feedback allowing early detection of nerve compromise, potentially preventing permanent deficits. However, the sensitivity and specificity of different monitoring modalities vary, and interpretation requires experienced neurophysiological expertise. While IONM appears to lower the incidence of nerve injury in cervical and thoracolumbar spine procedures, its routine use remains debated due to cost, false positives, and variable impact on long-term functional outcomes. Clinicians should weigh patient- and procedure-specific risk factors when considering IONM and remain aware of its limitations.
What the evidence shows
IONM encompasses techniques such as somatosensory evoked potentials (SSEPs), motor evoked potentials (MEPs), electromyography (EMG), and nerve conduction studies, applied intraoperatively to monitor neural pathway integrity. Hasan et al. (2025) provide a comprehensive review of nerve injuries in anterior cervical spine surgery, highlighting that IONM facilitates early detection of nerve root and spinal cord compromise, potentially reducing postoperative neurological deficits. Similarly, Basu et al. (2023) emphasize that multimodal IONM combining SSEPs and MEPs improves sensitivity for detecting both sensory and motor pathway injuries during complex spine surgeries.
Positioning-related peripheral nerve injuries represent a significant subset of nerve complications in spine surgery. Kiridly et al. (2021, 2022) report that IONM can detect early signs of peripheral nerve ischemia or compression due to patient positioning, such as ulnar nerve or brachial plexus injury, enabling intraoperative repositioning to mitigate injury risk. Their analyses across Contemporary Spine Surgery and Contemporary Neurosurgery journals underscore that IONM-guided interventions reduce the incidence of permanent positioning-related nerve injuries.
A recent review by Contemporary Spine Surgery (2024) consolidates evidence supporting IONM’s role in spine surgery safety but notes variability in monitoring protocols and outcome measures. The Handbook of Spine Surgery (2025) further discusses that while IONM can decrease the rate of neurological complications, its effectiveness depends on surgeon experience, anesthetic management, and institutional protocols.
Caveats and uncertainty
Despite promising data, several limitations temper enthusiasm for universal IONM use. False positive alerts can lead to unnecessary surgical delays or interventions, while false negatives may provide false reassurance. The quality of evidence is largely observational, with few randomized controlled trials directly comparing outcomes with and without IONM. Cost-effectiveness analyses remain limited, particularly in lower-risk procedures.
Interpretation of IONM signals requires specialized neurophysiologists and standardized protocols, which may not be available in all centers. Variability in anesthetic agents and physiological parameters can affect signal reliability. Additionally, the impact of IONM on long-term functional outcomes and quality of life is not fully established, as many studies focus on immediate postoperative neurological status.
Peripheral nerve monitoring for positioning injuries is less standardized than spinal cord monitoring, and thresholds for intervention vary. The heterogeneity of spine surgery populations and procedures complicates generalization of findings.
How this may change practice
Surgeons performing high-risk spine procedures, especially anterior cervical approaches and deformity corrections, may consider integrating multimodal IONM to enhance intraoperative safety. Awareness of positioning-related nerve injury risks and use of IONM to detect early signs can prompt timely patient repositioning, potentially reducing morbidity.
Institutions should develop standardized IONM protocols and ensure availability of trained neurophysiological personnel. Preoperative risk stratification incorporating patient comorbidities and surgical complexity can guide selective IONM use, optimizing resource allocation.
Further research, including prospective trials and cost-effectiveness studies, is needed to refine indications and protocols. Until then, clinicians should interpret IONM findings within the broader clinical context and maintain vigilance for nerve injury signs regardless of monitoring.