Intraoperative Neuro-monitoring During Spondylolisthesis Surgery

The development and maturation of the science and technology behind intraoperative neuro-monitoring (IONM) has been fundamental in the evolution of modern spinal deformity surgery. A number of studies have found that IONM is a highly sensitive and specific tool to recognize electrophysiologic changes at the level of the spinal cord. However, the literature describing the objective surgical outcomes for high-grade spondylolisthesis have a high rate of transient and permanent neuropraxia. The incidence of transient neuropraxia may be as high as 25% and permanent deficit may be up to 10% based on surgical technique, severity, and approach. This chapter will review several of the commonly used modalities for IONM and, also, present the authors’ technique for using the multiple IONM modalities including triggered EMG of the nerve root to identify potential nerve root lesions secondary to compression and/or stretch during reduction and stabilization of spondylolisthesis.