## 4 Discussion
The advantage of this novel device is that it offers real-time, hassle-free monitoring, thereby preventing pedicle screw malpositioning and nerve damage. When a pedicle screw is inserted using the freehand technique, the surgeon identifies the anatomical landmark and considers the transverse and sagittal pedicle angles. The surgeon then performs the five following steps: preparing a screw entry point, marking the screw trajectory using a pedicle finder or gear shift probe, palpating the trajectory to inspect the medial and inferior walls for breaches, tapping, and finally inserting the pedicle screw. The neural structures are exposed to potential damage during this five-step process, except while creating an entry. Utilizing a conventional nerve stimulating probe involves the hassle of removing the surgical instruments used at each step to insert the probes. As described above, because the neuromonitoring using conventional probes is performed after completing each step, it is difficult to view it as real-time monitoring as it would have the disadvantage with respect to time and the technical aspects. In contrast, the newly developed magnetic stimulating probe can easily be attached to and detached from the surgical instrument used at each step, thus making it is less cumbersome to replace. Moreover, it can be utilized as a real-time warning tool for pedicle screw malpositioning to avoid neural complex injury. However, if the surgical tool is rotated clockwise during tapping or screw fixing, the magnetic probe may fall off because it is only connected magnetically. To reiterate, if the pedicle is broken or nerve damage occurs, the conventional probe could check nerves only after each surgical step is completed, so it is impossible to know the nerve damage in real-time. However, our magnetic probe could prevent nerve damage in advance. It could serve as a real-time neuromonitoring system because it could attach to the surgical tool in every step. Therefore, this novel magnetic stimulating probe that can recognize pedicle wall breach or neural insult in real-time while placing a pedicle screw may be considered to be more valuable than a conventional stimulating probe. Image-guided systems, i.e., 2D fluoroscopy and intraoperative 3D scanning, are the most widely used surveillance devices during spinal surgery [7; 8]. Although they have the advantage of being easy to use, these imaging devices only provide information about the anatomical relationship between the pedicle screw and surrounding structures but do not directly inform whether or not neurological damage has occurred. In other words, it is not enough to infer that the nerves may have been injured by figuring out the abnormal screw position. Unlike these image-guided systems, the electrophysiology-based neural monitoring device is somewhat cumbersome but has the advantage of directly detecting neural damage, and no additional irradiation is required. As in this study, if a neural monitoring system capable of real-time monitoring that does not require additional procedures, effort, and time other than surgery is introduced in the near future, it could be a future-proof alternative for image-guided systems and is expected to help doctors with challenging surgery or less experience. In addition, it is difficult or impossible to conduct ION with conventional probes in revision or endoscopic surgeries. However, using our novel stimulating probe could enable hassle-free and convenient ION during revision surgery or endoscopic spine surgery, in which it is challenging to identify anatomical structures. The distance and positional relationship between the neural tissue and the surgical instrument used could be verified and monitored in real-time without replacing the instrument or the probe. Additionally, it can be applied not only in lumbar spine surgeries, but also in all areas of spinal surgery such as cervical degenerative diseases and spinal deformities.