The cortical somatosensory evoked potentials (CSEP) is one of the electrophysiological tests to determine the sensory pathways in the spinal cord, which can be used to quantify spinal cord function more accurately and is useful in the determination of spinal cord disorders, intraoperative monitoring, and prognostic assessment. Since 1977, when somatosensory evoked potentials were used for intraoperative monitoring, CSEP has been increasingly used in the field of spinal cord surgery. CSEP is conducted by sensory impulses through the posterior cord of the spinal cord, i.e., the thin bundle and the cuneiform bundle, and because the sensory area of the spinal cord is very close to the anterior horn of the spinal cord and is surrounded by the arachnoid membrane as a whole, CSEP examination can detect spinal cord injury and its extent in a timely manner. 1. Correlation between the degree of spinal cord injury, prognosis and CSEP test results The degree of spinal cord injury can be expressed quantitatively by Frankel’s classification, but it is often affected by subjective factors. In this group of cases, the CSEP test results are consistent with the spinal cord grading. Patients with type I manifestations are mostly spinal cord transection and complete paresis, and surgical decompression is not significant for spinal cord recovery, and the postoperative symptom relief is not ideal; patients with type II manifestations are mostly those with severe spinal cord damage and incomplete paresis, and surgery can create certain conditions for spinal cord recovery, but the efficacy is uncertain; patients with type III manifestations have mild spinal cord damage, and surgical decompression is significant for spinal cord recovery. CSEP is an important tool to diagnose spinal cord injury and determine the evolution of reversible spinal cord injury, as it can provide a more accurate functional diagnosis and quantitative analysis of the spinal cord. The present group of cases showed that CSEP findings correlated well with the degree of spinal cord injury, but also with the rate of postoperative symptom relief, which to some extent helps in the choice of treatment. In addition, CSEP has a central amplification effect, is very sensitive, and responds to changes in disease 3-4 weeks earlier than clinical signs, so the prognosis can be judged according to the degree of shortening of the latency period. 2, CSEP in the spinal cord surgery monitoring role Early detection of reversible spinal cord injury, determine the degree of injury, effective prevention of medically induced paraplegia is an important purpose of CSEP monitoring in spinal cord surgery. It can identify acute injury and its site in the nerve conduction pathway, and correct the causative factors in a timely manner, thus greatly improving the safety of spinal cord surgery. In this group of cases, the surgical operations that are prone to spinal cord injury are, in order of priority: resection of vertebral tumors or occupying lesions in the spinal canal, orthopedic scoliosis with concave lateral bracing, posterior cervical “single-opening” vertebroplasty, removal of the thoracic spinal stenosis lamina, and placement of the lamina hook under the thoracic lamina. In the author’s opinion, CSEP has the most obvious value in spinal cord tumor resection and scoliosis orthopedic surgery. During scoliosis orthopedic surgery, especially during concave bracing, the spinal cord and blood vessels are susceptible to stretching changes, and excessive stretching can lead to local ischemia of the spinal cord, and CSEP is sensitive to the ischemic changes of the spinal cord, immediately showing prolonged latency, decreased amplitude, and even loss of waveform. During tumor resection, CSEP can also help identify the nerve tissue around or within the tumor, ensuring that the surgeon performs a more extensive and optimal operation. In addition, monitoring documentation has potential value to surgeons and anesthesia personnel in forensic medicine, and procedures without monitoring may be considered to lack safety standards. 3. CSEP monitoring criteria Currently, CSEP monitoring is limited to the observation of wave amplitude and latency changes. A 10% increase in latency and/or a 50% or more decrease in wave amplitude indicates impairment of spinal cord function, which is currently the generally accepted “gold standard”. In fact, it is difficult to establish a single standard due to the severity of the disease, the location of the lesion, and the surgical operation. In the present study, the sensitivity of different monitoring criteria was 100%, while the specificity was significantly different, and criterion II was more practical. In the author’s opinion, monitoring criteria are flexible within a certain range, varying with disease, site and operation, and it is a challenging task to detect changes in waveforms and reveal their causes. While it is important to detect valuable changes in a timely manner, too much information may interfere with the operator’s operation; and wrong information may lead to irreversible and serious consequences, and no information is better than wrong information. When the CSEP waveform changes to an “alarm value,” the monitor should watch for every small change; it is also helpful to be familiar with each important step in the procedure and to communicate with the surgeon in simple, intuitive terms. In addition, we should be alert to the rare possibility that the motor bundle is damaged while the sensory bundle is intact, and the patient may have severe motor nerve damage without CSEP changes after surgery; we should also pay attention to the establishment of the baseline wave before surgery and after anesthesia, and compare the potential changes with the baseline wave during surgery and correlate with the patient’s clinical performance to find valuable information more accurately. 4. Relationship between CSEP and other evoked potentials In addition to CSEP, other monitoring techniques developed in recent years include subcortical somatosensory evoked potential (sub-CSEP), spinal somatosensory evoked potential (SSEP) and motor evoked potential (MEP). According to the literature, multi-point recording of somatosensory evoked potentials or the combined application of multiple modalities of SEP and MEP monitoring has good resistance to interference and can better reflect not only the functional integrity of the spinal cord, but also has been used to respond to the depth of anesthesia, circulatory status, etc. CSEP records the electrophysiological activity generated by peripheral stimuli transmitted to the cerebral cortex via level 3-4 synapses, which is relatively less resistant to interference and vulnerable to However, with the development of hardware equipment, the sensitivity and anti-interference of CSEP monitoring have been significantly enhanced, and at present, as long as a ground wire is connected intraoperatively, other factors have less influence on CSEP, except for the need to suspend monitoring when using an electric knife. In addition, CSEP does not require exposure of the dura mater or stimulation of the cerebral cortex, which makes it easier and safer to use for preoperative examination and postoperative evaluation, showing its unique appeal in the diagnosis and treatment of spinal cord disorders.