Minimally invasive surgical treatment of extreme lateral lumbar disc herniation With the development of modern minimally invasive spinal surgery techniques, minimally invasive column surgery techniques have become an ideal choice for the treatment of extreme lateral lumbar disc herniation. Surgical methods (a) YESS (WOLF, Germany): transverse posterior intervertebral foraminal approach for disc removal and foraminal enlargement. After the operation, patients were given intravenous broad-spectrum antibiotics for 3-5 d. After 1-3 days, patients started to get out of bed under the protection of lumbar girdle and gradually strengthened the functional exercise of lumbar and back muscles. (ii) METRx (American pivotal model) posterior transverse interbody approach lumbar disc removal. Postoperative intravenous antibiotics are administered for 3-5 d. After 3 days, patients can get out of bed as appropriate. (c) X-Tube (U.S. pivot model): Posterior transforaminal resection and internal fixation with intervertebral bone graft fusion. Dehydration, hormone and neurotrophic drugs were used as appropriate during the first week after surgery to reduce postoperative neural edema and accelerate the recovery of neurological function. Antibiotics were used routinely for 5-7 days after surgery. The patient should stay in bed for 1 week and then go out of bed with a waist cuff, and excessive activities and strenuous exercise should be restricted for 3 months. I. Clinical classification of extreme lateral lumbar disc herniation Extreme lateral lumbar disc herniation means that the prolapsed or protruded intervertebral disc tissue is located inside or outside the intervertebral foramen, which leads to the spinal nerve root of the same segment to be compressed by the prolapsed or protruded intervertebral disc tissue inside or outside the lumbar intervertebral foramen, resulting in intense radiating pain in the lower limbs with lumbosacral pain in the innervation area of the same segment nerve root, accompanied with varying degrees of nerve root innervation area of the damaged nerve root. This causes severe radiating pain in the lower limbs with lumbosacral pain in the same segmental nerve root innervation area, accompanied by different degrees of skin sensory or motor function impairment in the damaged nerve root innervation area. According to the location of the herniated disc, we categorize the extreme lateral lumbar disc herniation into 3 types: intraforaminal (type I), extraforaminal (type II), and mixed (type III). Minimally invasive treatment strategies for extreme lateral lumbar disc herniation The traditional surgical approach to extreme lateral lumbar disc herniation is posterior transforaminal hemilaminectomy and synovectomy. Although this procedure can adequately visualize the herniated disc within or outside the intervertebral foramen, the destruction of the synchondrosis on one side of the intervertebral foramen brings or aggravates lumbar spine instability, which leads to or aggravates lumbosacral pain in the patients after the operation. In response to these problems, Kunogi et al. recommended that lumbar fusion should be performed in all patients who undergo synovectomy through the lumbar laminar space. In 1982, Schreiber et al. reported the first endoscopic nucleus pulposus removal via the posterior lateral approach, and in 1983, Kambin et al. reported arthroscopic discectomy via the posterior lateral intervertebral space, and in 1997, Yeung developed the third generation of the Yeungendoscopy spine system (YESS). With the continuous development of this technology, it has evolved from simple bulging and herniated disc removal to extreme lateral herniated disc removal, as well as intervertebral foramenoplasty with synovectomy, lateral socket decompression, and so on. From the early indirect decompression to endoscopic direct decompression. The YESS technique was used in 25 patients in our group, and compared with the other two surgical methods, the anesthesia was simple and easy to perform, the surgical incision and bleeding were minimized, the operation time and bedtime were shortest, and the surgical excellence rate reached 84.0%. Moreover, it was an extra-vertebral canal surgery, which avoided the disadvantages of entering the spinal canal and disturbing the intra-vertebral canal structures. Therefore, we believe that lateral posterior spinal endoscopic surgery is a truly minimally invasive procedure, especially suitable for simple type I extreme lateral lumbar disc herniation. Because of the difficulty of this technique, it should be used with caution for type II and type III extreme lateral lumbar disc herniation in the early stage of the development of this technique. The transverse interbody approach has been advocated by many scholars in recent years. During the operation, the lumbar arch root isthmus, articular eminence and upper and lower transverse processes are fully exposed, and then the intertransverse membrane is incised to dissect and expose the posterior part of the intervertebral foramen, the nerve roots and the intervertebral discs. The main advantages of the transverse intertransverse approach are: minimal surgical trauma, no opening of the lumbar spinal canal, and no compromise of lumbar spine stability. We used the METRx endoscopic transverse intervertebral disc approach, and the clinical application proved that although this procedure requires a high level of anatomical knowledge and the ability of the surgeon to “separate the hand from the eye” under the cavity lens, it is a new minimally invasive procedure for the treatment of lumbar disc herniation outside the foramen ovale, as it is minimally invasive, with a clear view of the surgical field, and can achieve excellent results with a fine technique. It is a new minimally invasive procedure for the treatment of extraforaminal lumbar disc herniation. Therefore, we believe that type II extreme lateral lumbar disc herniation is the best indication for transforaminal METRx endoscopy. Transforaminal lumbar interbody fusion (TLIF) was first reported by Harms et al. and is now widely recognized and used by clinicians. The most important advantages of this procedure are that patients have less postoperative pain, less traumatic reaction, and faster recovery. We believe that extreme lateral lumbar disc herniation with neural root canal stenosis or degenerative lumbar instability is the best indication for minimally invasive endoscopic (X-Tube) transforaminal resection and decompression, and is also the best minimally invasive revision procedure after the failure of YESS and METRx.