Zheng Baosen, Department of Pain, Central Hospital$ Most patients hospitalized for lumbar disc herniation have experienced the disappointing process of the gradual ineffectiveness of conservative treatments, and have high hopes for surgical treatments; however, the potential risks of traditional open surgeries as well as the possible postoperative complications have deterred many patients from undergoing them. Therefore, minimally invasive treatment, which is highly effective and low-risk, has been widely favored by patients, and its development is naturally changing rapidly. After the dark stage of disc excision and suction under blind vision and X-ray fluoroscopy, the application of microscope brought a new era of minimally invasive treatment, and the introduction of fiber-optic endoscopy technology brought a revolutionary development of minimally invasive treatment. In terms of surgical access, it has also undergone a revolutionary development from posterior transforaminal approach to lateral posterior transforaminal approach. Transforaminal approach does not damage the posterior spinal structures at all, ensuring the stability of the spine, and also skillfully avoids the interference with the important structures in the spinal canal, such as the dural sacs and the nerve roots, which greatly reduces the risk of the surgery. An early representative of the transforaminal approach was the Yeung endoscopic spine system (YESS), which was used by Yeung et al. to access the intervertebral disc via the Kambin safety triangle for indirect decompression. YESS, a technique that is effective in treating simple disc herniation and is much safer than traditional open surgery. However, after the disc tissue has prolapsed or traveled to a distant location, the YESS technique is powerless. Dr. Hoogland invented a set of special tools, including puncture needles of different diameters, intervertebral foraminal reamer, working trocars, and endoscopic system. after puncturing the anesthesia with accurate positioning, the intervertebral foramen is gradually enlarged with reamer, the working trocars are inserted, and the endoscopic system is utilized to remove the prolapsed or free lumbar disc tissues under direct visualization. tessys technology, because of the ability to enter into the intravertebral canal for operation, can treat not only lumbar disc In addition to herniation, it can also treat foraminal stenosis, hypertrophy of the ligamentum flavum, and calcified degeneration of the intervertebral discs, etc. The TESSYS technique has also gone through two generations of development, with the first generation system using an annular saw bone auger, which is not strong enough to cut through the harder bone and is prone to damaging the nerve roots below. As the access can be adjusted, disc herniation to the posterior dural space can also be handled. Disc herniation in the L5~S1 segments can be handled much more easily, the risk of nerve injury is once again reduced, and more importantly, the learning curve has become less steep. Since the second generation of TESSYS technology was developed by Dr. Hoogland in collaboration with the German company maxMore, it is distinguished from the first generation of TESSYS technology, which is also known as maxMore technology. The combined advantages of the TESSYS technique over traditional open surgery in terms of surgical results, indications and complications are very clear. Although many patients still undergo traditional open surgery, with the improvement of TESSYS, not only are the surgical results comparable to or better than those of open surgery, but also the indications for the surgery are getting wider and wider, and it is now able to handle most cases of herniated discs, most cases of foraminal stenosis, and even lumbar spondylolisthesis of less than II degree. Therefore, more and more people will choose this latest minimally invasive surgical technique because, even though open surgery has further developed and the incision has gradually become smaller, the result of destroying the muscles and ligaments that maintain the stability of the spine has not been substantially changed, and general anesthesia and prone position are still required, and the complications and risks associated with it should not be underestimated. In addition, too much pursuit of small incisions will also cause insufficient intraoperative vision, reluctant surgery is bound to cause more risks, while TESSYS technology is operated entirely under the endoscopy, not only minimally invasive, but also a clear field of vision, the advantages of self-evident. Compared with discoscopy, TESSYS technology also has obvious advantages in terms of surgical results, indications and complications. Although the latter combines microdiscectomy and endoscopic techniques to achieve excellent results, discoscopic surgery also has obvious shortcomings. First, this kind of surgery needs to be performed under epidural anesthesia or general anesthesia, and the anesthesia process itself has a greater impact on the patient’s organism, which has a certain degree of risk. Secondly, the surgery is performed through the intervertebral approach, which destroys the ligamentum flavum and affects spinal stability, and may also form scar tissue to compress the dural sac or nerve root adhesions[5] . Third, because discoscopy cannot use water as a medium like foraminoscopy, the clarity of its surgical field cannot reach that of foraminoscopy. Fourth, comparing from the perspective of complications, because discoscopy enters the spinal canal from the posterior approach, the space is narrow and there is no room for maneuver, so the chances of acute cauda equina syndrome occurring in the postoperative period are significantly more than that of intervertebral foramenoscopy surgery, and the chances of adhesion occurring in the nerve root are also significantly more. Fifth, in terms of the range of indications, discoscopy is relatively narrow, and although it can remove herniated disc tissue in most cases, and can even decompress the lateral socket and remove free disc fragments, it is unable to deal with extremely lateral-type herniated discs, and it can do nothing for adhesion lesions on the ventral side of the nerve root. In particular, calcified disc tissue following a common central herniation is not only difficult to handle with discoscopy, but also extremely risky. However, the above situation is much easier to handle with the TESSYS technique, which can handle almost all common types of herniated discs due to its access from the intervertebral foramen to the anterior dural space at the posterior border of the vertebral body, and with the advent of the second-generation TESSYS technique, the very rare scenario of a herniated disc that has become free in the posterior dural space can also be easily handled. The first is the ability to deal with foraminal stenosis, one of the lumbar spinal stenosis conditions. Lumbar spinal stenosis is mostly due to spinal degeneration in the elderly. Spinal degeneration is mainly manifested by hyperplasia and hypertrophy of the lumbar articular process, which further leads to bony stenosis of the neural foramina, in which the common cause of stenosis in the lateral travel area is osteophytes at the posterior margin of the vertebral body outside of the foramen. The common clinical stenosis segments are L5~S1 segmental neural foraminal stenosis, which manifests as lower extremity neurogenic pain, numbness and neurological impairment characterized by L5 nerve root injury. In the past, open surgery was used to enlarge and shape the intervertebral foramen, which was very destructive to the normal structures in the posterior region, but the maxMore technique can effectively avoid the damage to the normal structures.Ruetten et al.[11] used it in the enlargement of intervertebral foramen to decompression surgery to achieve good results, and he believed that compared with the traditional laminectomy and decompression surgery, the maxMore technique has less interference with the spinal motion segment and avoids the durability of the laminae, so that it is more convenient for the patients. less interference and avoided the occurrence of epidural fibrosis. Zhou Yue et al. also used this technique to treat nerve root canal stenosis in the L5~S1 segments and achieved good results. He believed that the hyperplasia and hypertrophy of the bone of the superior articular process of S1 was the main obstacle to the insertion of intervertebral foraminoscopic instruments, and that the use of the spiral bone drill invented by Dr. Hoogland made it easy to manipulate and adjust the direction, and it was easy to remove the calcified material and the hyperplasia and the anterior design with neuroprotection, which would not cut off the nerve root. Nerve roots will not be cut. After entering the spinal canal, the first step is to remove the remaining bone fragments and ligamentum flavum in the intervertebral foramen, and then to separate the fibrous scar tissue in the nerve root canal can effectively decompress. Continuously collecting and organizing, it is found that the manifestations of intervertebral disc herniation under the microscope are various, and their manifestations are related to the type of intervertebral disc herniation as well as the patient’s age, the cause of the onset of the disease, and the duration of the disease. With the continuous development of TESSYS technology itself, its field of application will also be further developed, therefore, the Department of Pain Medicine of the First Center Hospital will also continue to carry out in-depth research in this area, so as to make this technology more perfect and safe.