Minimally invasive surgery is one of the fastest growing areas of modern surgery, enabling small “hole” incisions combined with visualization techniques that allow for better viewing of the surgical area. The origin of the term “minimally invasive surgery” is somewhat controversial; Wickham coined the term in 1986, and in 1992, Cuschieri used the term “minimally access surgery. Minimally access surgery”. In the past decade, minimally invasive spine surgery techniques have evolved rapidly. Minimally invasive spine surgery reduces postoperative pain and recovery time because it involves less stretching and stripping of soft tissues. With the development of microendoscopic techniques and the clinical application of special surgical instruments and equipment, surgeons can perform previous surgical operations through one or more tiny incisions. As with open surgery, minimally invasive spine surgery also enables minimally invasive nerve decompression, spinal stabilization and fusion, and correction of spinal deformities. I. Current status and outlook of minimally invasive spine technology 1. posterior posterolateral percutaneous discectomy Percutaneous discectomy for decompression of lumbar disc herniation has undergone a history of development for more than 20 years. On the basis of Craig’s lateral posterior percutaneous lumbar disc puncture biopsy route, Hijilkata and Onik et al. reported lateral posterior percutaneous lumbar discectomy manually and automatically, Kambin et al. reported endoscopically assisted lumbar discectomy and aspiration, followed by Forst and Schreiber et al. who reported lumbar discectomy and decompression under direct endoscopic view, respectively. With the continuous improvement and development of minimally invasive spinal endoscopes and surgical instruments, as well as the clinical application of advanced surgical equipment such as laser, radiofrequency, and navigation, percutaneous laminectomy techniques have been revolutionized. From the early blind postero-lateral percutaneous lumbar discotomy to today’s endoscopically assisted excision and aspiration, from the YESS technique of indirect disc decompression by simply entering the disc through the Kambin safety triangle to the TESSYS technique of direct nerve root release and decompression by entering the spinal canal directly through the intervertebral foramen, from the past when only simple inclusive lumbar disc herniation could be performed to the present day when all types of lumbar disc herniation can be completed. The procedure has become the most promising and minimally invasive endoscopic technique of the spine today. Efforts are being made to explore percutaneous lumbar fusion, nucleus pulposus replacement and stem cell transplantation. This procedure has become the most promising and minimally invasive endoscopic technique of the spine today. Percutaneous lumbar discectomy (PELD) is a posterior-lateral approach to the disc through the “safe triangle of work” of the intervertebral foramen. This zone is located on the posterior aspect of the annulus fibrosus and allows safe passage of instruments without damaging the exiting nerve root. Minimally invasive posterior posterolateral percutaneous discectomy can be performed under local anesthesia so that the surgeon can receive direct feedback from the patient during placement of the working channel to avoid injury to the nerve root. Despite the significant advantages of this procedure, such as minimal bleeding, minimal surgical trauma and scarring, there are still some drawbacks. If the patient’s iliac crest is high or the patient’s spinal space has collapsed, it can be difficult to find the precise point of access. It is also difficult to operate when the disc fragments are already free. The risk of nerve root injury is also higher in patients requiring general anesthesia or deep sedation. With the continuous improvement and development of minimally invasive spinal endoscopy and surgical instrumentation, as well as the clinical application of advanced surgical equipment such as laser, radiofrequency, and navigation, percutaneous laminectomy techniques have been revolutionized. From the early blind postero-lateral percutaneous lumbar disc dissection to today’s endoscopically assisted excision and suction, from the past, when indirect disc decompression was performed simply by entering the disc through the Kambin safety triangle, to today’s direct nerve root release and decompression by entering the spinal canal directly through the intervertebral foramen, from the past, when only simple inclusive lumbar disc herniation could be performed, to the present day, when all types of lumbar disc herniation and In addition to direct surgical removal of all types of herniated and prolapsed lumbar discs and percutaneous foraminal enlargement for foraminal stenosis, we are now exploring percutaneous lumbar fusion, nucleus pulposus replacement and stem cell transplantation. This procedure has become the most promising and minimally invasive endoscopic technique of the spine today. Percutaneous foraminoscopic lumbar interbody fusion is an important future development direction. Currently, scholars are trying to fill the disc with a balloon with a gel or polymer expansion device through a special surgical tool, and the balloon can be expanded to the desired size. Another approach is to use an expandable intervertebral fusion device that is implanted into the disc through the percutaneous intervertebral foramen “safety triangle” and then prolongs and expands to the appropriate size, thus achieving true minimally invasive percutaneous intervertebral implantation, intervertebral prolapse fixation and fusion. Although it is difficult to insert into the disc, it is possible to design a smaller size deformed intervertebral fusion device that can be inserted into the disc and then regain its shape to achieve minimally invasive intervertebral fusion. The development of a PEEK expandable intervertebral fusion device has been achieved in materials and has been used clinically. Although percutaneous sublaminar discectomy has many advantages, it also has shortcomings. Endoscopic surgery limits the surgeon’s vision to the narrow field of view of the endoscopic camera, a two-dimensional space, and the lens is often obstructed by blood and water spray, posing the risk of injury to important neurovascular and visceral organs, which is why the clinical application of spinal endoscopic surgery is limited. To ensure the accuracy and safety of the procedure, physicians must again operate under X-ray fluoroscopy, thus being exposed to large amounts of X-rays. The most meaningful advancement to address the surgical risks posed to the surgeon and patient with spinal endoscopy is the clinical application of image navigation technology. Image navigation enhances the surgeon’s ability to control instruments, enterprises, and specific anatomical structures by using preoperative and intraoperative individual data of a particular patient for anatomical localization, displaying instrument trajectory and position. We speculate that in the future, minimally invasive percutaneous discectomy will evolve into a precise operation guided by image navigation. Of course, the use of imaging navigation in percutaneous discectomy still has the following problems: (1) current images do not yet clearly show the nerve roots, which makes it difficult to completely avoid nerve root injury. (ii) Current navigation systems require fixation of bony landmarks for image alignment, but in posterior posterolateral percutaneous subdiscal discectomy the endpoint is within the disc and does not involve bony landmarks. Bone surface registration alignment is not completely accurate, and even if it is plausible, the long distance to the working area produces large inaccuracies. A solution to this problem is the use of intraoperative biosensors. Advances in microprocessor technology have resulted in smart sensors that integrate sensing and data processing functions on an integrated circuit chip (IC chip) and are used for medical purposes. Andrews et al. used this technology to discriminate tissue in vivo (Real-time) under different conditions with the aim of improving the technique for immediate discrimination between nerve roots and peripheral tissues, and to find the correct site for posterior posterolateral percutaneous subdiscal discectomy instrumentation. The aim is to improve the technique for immediate differentiation of nerve roots and peripheral tissues and to find the correct safe point of entry into the intervertebral space. MED minimally invasive lumbar disc removal is a new minimally invasive spine surgery technique first developed by Foley and Smith in 1997. The MED minimally invasive lumbar disc removal technique draws on the advantages of traditional posterior laminectomy and minimally invasive endoscopic techniques to create a series of dilated passages to complete the surgical approach, and to perform laminectomy, subtotal joint resection, nerve root canal decompression, and disc removal through 1.6-1.8 cm?-diameter working passages that could only be accomplished through open surgery in the past. Compared to conventional lumbar disc removal, this technique creates a surgical access through a series of dilating catheters, eliminating the need for stripping and distraction of the paravertebral muscles and completing all surgical operations within a 1.6-1.8 cm?-diameter working channel. As a result, it has the advantages of a small surgical incision, minimal paravertebral muscle damage, minimal bleeding and rapid postoperative recovery. The advanced camera and video system magnifies the surgical field of view by 64 times, so that the dural sac, nerve roots and vascular plexus in the surgical area can be more accurately identified and protected during surgery; at the same time, the clear surgical field ensures more precise completion of various surgical operations, effectively avoiding the shortcomings of deep field of view and large damage to the posterior bony joint structures of the spine in traditional surgery, and maximally preserving the integrity of the posterior spinal ligament complex. The integrity of the posterior ligamentous complex of the spine is preserved to the maximum extent, thus effectively reducing the occurrence of postoperative scar adhesions and lumbar instability. The location of the working channel is determined by the pathological changes in the specific area. Minimally invasive lumbar decompression allows for adequate decompression of the central spinal canal, lateral saphenous fossa, and intervertebral foramen regions. In addition, the disc tissue outside the foramen can be removed. The surgical approach needs to be planned prior to decompression of the different areas. For extraforaminal nerve decompression, the working channel can be placed on the intertransverse interlaminar membrane between the transverse processes by first identifying the intertransverse interlaminar membrane and dissecting the intertransverse ligament to reveal the deeper exiting nerve root, which can then be located deep within the nerve root. Recent studies comparing minimally invasive disc nucleus pulposus removal with traditional open surgery have shown that minimally invasive surgery involves less tissue damage, less nerve interference, less blood loss, less postoperative pain, shorter hospital stay, and faster recovery and return to work. A randomized controlled study of traditional open microdiscectomy and microdiscectomy with minimally invasive access showed that the procedure was safer and more effective with minimally invasive access. The new discoscopic (MED) technique developed by Foley and Smith is a combination of minimally invasive microsurgical techniques and endoscopic techniques.MED surgery is similar to open microscopic discectomy and can be used for laminectomy decompression and foraminotomy as well as herniated disc surgery.The ease of operation, broad indications and versatility of MED make it easier for surgeons to switch from traditional surgery to endoscopic surgery. Although endoscopic visualization not only provides a clear and magnified view of the surgical field, but also facilitates efficient surgical procedures, it provides only 2-dimensional images and is often hampered by bleeding and poor display, which is not as good as microscopic discectomy. Advances in endoscopic imaging and endoscopic image fusion techniques can help improve this problem. Bleeding control is particularly important for any visualization technique, and heavy bleeding increases the risk of dural sac tears and nerve root injury. Endius has developed a miniature bipolar electrocoagulation (MDS) device with a double sheath that can be applied to perform blunt dissection, aspiration and electrocoagulation to stop bleeding. A dual light source endoscopic system (infrared/visible) is also used, which incorporates an infrared channel in the current laparoscopic system. This system is able to find small arterial bleeds in a bleeding environment, identify the exact location of the bleed, and help the operator to rapidly cauterize the bleed and reduce repeated hemostatic operations when the bleeding site is unclear. Most current spinal endoscopes claim to have 20× magnification when using a xenon or halogen light source and can reach 3×104 pixels. Recent visualization techniques can achieve 5×104 pixels with a 1.8 mm fiber diameter, and this image quality is sufficient for most current procedures. Future spinal endoscopic procedures will benefit from smaller optical fibers that provide more room for surgical manipulation without loss of image quality. Another advancement is the dual illumination, where the MGB endoscope applies a telescope system called Shadow, which uses 2 separate illumination sources integrated into a standard 30° surgical endoscope, which provides excellent plasticity and contrast due to the structure of Shadow, which allows conversion to 3D images for high resolution as well as a uniformly clear surgical field of view. Another improvement of the spinal endoscope is the anti-fogging system, where re-fogging after external cleaning can lead to repeated interruptions of the procedure. Maintaining a clear field of view is particularly important for the safe performance of minimally invasive spine surgery. In 1993, a study was done to add an additional “sheath” (outer tube) to the conventional endoscope that could clean and dry the optics at any time, so that the lens remained clean and did not have to be repeatedly withdrawn from the patient. The addition of a mist eliminator removes smoke from the high-frequency surgical scalpel. Unfortunately, the system cannot stop the natural fogging caused by the imbalance between the temperature of the lens and the humidity of the working area, and some companies have tried to solve this problem by adding receptors and heat-resistant filaments to the rear of the lens lens. The CCD chip-based High Definition Imaging (HDI) feature provides 2 million pixels in 1250 horizontal lines, which allows for a clearer and more distinct surgical field of view. Advances in computer technology and endoscopic techniques have enabled 3D reconstruction of virtual images, synthesized from preoperative images combined with intraoperative scans, which are then appended to intraoperative endoscopic images, and similar techniques have been used in cranial surgery to combine preoperative image reconstruction with intraoperative surgical microscopy images, which can assist surgeons in identifying tumor boundaries and better removing tumors. Recently, (Mississauga, Canada) a neuroendoscopic trocar has been developed that allows the endoscopic position to be seen based on MRI and CT data. Special software provides live endoscopic images as well as three-dimensional positioning of the instruments. Another development is the helmet display ophthalmoscope, which is attached to the operating microscope so that the operator can observe the transmitted display signal and the surgical field of view, which could also be used in the near future for spine surgery endoscopy to compensate for the lack of a two-dimensional spine endoscope. Future improvements in imaging technology will also include better optical image resolution, better focus similar to that of an operating microscope, better flexibility and maneuverability, greater working channel role, and continued improvements in three-dimensional images. These improvements can advance spinal endoscopic surgery to a whole new level. 3. Problems and challenges facing anterior spinal lumpectomy The era of surgical endoscopy began with the introduction of television-assisted endoscopic techniques in the late 1970s. With the rapid development of minimally invasive techniques such as arthroscopic techniques, laparoscopic techniques, thoracoscopy, and intervertebral discoscopy, traditional open techniques have now been replaced in the surgical treatment of many diseases. Due to the special anatomical structure and surgical requirements of the spine, anterior minimally invasive spine surgery faces more clinical problems, greater surgical difficulties, and the highest surgical risks and complications, thus significantly limiting and hindering the development and progress of anterior endoscopic spine surgery. The lumpectomy-assisted anterior cervical foraminotomy decompression began in the 1990s and has the advantage of being less invasive and preserving the cervical intervertebral disc, thereby preserving its motor function. Jho believes that the cervical 6-7 intervertebral space, the lateral aspect of the hook vertebral joint, and the transverse foramen are the most vulnerable sites for vertebral artery injury. To avoid injury to the vertebral artery, Jho recommends cutting the cervicalis longus at the level of cervical 6, where the muscle stump will retract toward the cervical 7 transverse process, thus exposing the vertebral artery beneath the cervicalis longus; at the hook vertebral joint, to avoid injury to the vertebral artery, the transverse foramen should not be entered when using a grinding drill. The bone can then be removed with a sphincter. In patients with unilateral radicular symptoms, anterior discectomy is followed by contralateral radicular symptoms due to cervical instability. Interbody fusion is required to maintain cervical stability, but minimally invasive anterior cervical fusion and fixation is an unsolved clinical problem. Modern thoracoscopic techniques began in the early 1990s, and with the continuous development of this technology, lung lobectomy, thymectomy, pericardium, and treatment of pleural diseases have been gradually accomplished. At present, thoracoscopic technology has been applied to the treatment of vertebral lesion biopsy, abscess drainage and removal of spinal lesions, nucleus pulposus resection for thoracic disc herniation, anterior decompression and internal fixation of thoracic fractures, and release and fixation of scoliosis correction or posterior protrusion deformity. Its effectiveness and safety have been widely recognized. However, compared with traditional open-heart surgery, thoracoscopic anterior minimally invasive spine surgery not only has the same incidence of surgical complications, but also takes longer, is more difficult, and carries higher surgical risks. in 15 thoracoscopic surgeries performed in 14 patients with thoracic disc herniation, Dickman et al. experienced three cases of pulmonary atelectasis, two cases of intercostal neuralgia, one case of screw loosening requiring removal, one case of intervertebral disc residue requiring McAfee et al. reported a 2% incidence of active bleeding, 5% incidence of pulmonary atelectasis, and 6% incidence of intercostal neuralgia after thoracoscopic minimally invasive spinal crutch surgery, in addition to serious complications such as spinal nerve injury, celiac disease, and damage to the septum and other organs. Lv Guohua et al. reported that the complications of thoracoscopic anterior spinal surgery included; 2.6% of intermediate conversion to open chest surgery for bleeding due to odd vein injury, 5.2% of lung injury, 2.6% of celiac disease, 5.2% of localized pulmonary atelectasis, 5.2% of exudative pleurisy, 10.5% of thoracic drainage time >36h and drainage flow >200ml, and 2.6% of numbness or pain in the chest wall locking hole, and clearly pointed out that in Watanabe et al. counted 52 patients undergoing thoracoscopic and laparoscopic scoliosis, and the complication rate was as high as 42.3%. Such a high complication rate and surgical risks thus hinder the development of thoracoscopic anterior thoracic spine surgery. For this reason, many scholars have recommended and adopted thoracoscopically assisted small-incision anterior thoracic spine surgery, which is not only relatively simple to perform, but also significantly reduces the operative time. In the late 1980s, the first laparoscopic cholecystectomy performed by DuBois et al. in France brought about a revolutionary development in laparoscopic techniques. Today, laparoscopic anterior spine surgery is mainly used for lower lumbar discectomy and intervertebral fusion (ALIF). Although, ALIF performed by laparoscopic technique can effectively reduce the tissue damage. However, transabdominal ALIF requires the establishment of a pneumoperitoneum, which can lead to ventilation difficulties and air embolism when the abdomen is inflated during laparoscopic surgery and the position is adjusted to a head-down position. In addition, complications of anterior lumbar fusion include extra-abdominal hernia, abdominal organ injury, injury to the great vessels, arterial embolism, medically induced intradural nerve injury, retrograde ejaculation, and instrumentation fracture. The problem of retrograde ejaculation after lumbar spinal fusion is receiving increasing attention. This is due to injury to the nerve plexus innervating the lower abdomen located anterior to the lower lumbar spine during the operation. regan et al. reported a 5.1% incidence of retrograde ejaculation in 215 laparoscopic lower lumbar interbody BAK fusion procedures. The FDA evaluation of LT-CAGE in laparoscopic implantation of interbody fusion reported retrograde ejaculation in up to 16.2% of male surgical patients, and the incidence of these complications was significantly higher than that of conventional open surgery.Newton et al. concluded that thoracoscopic anterior spinal surgery had a similar complication rate to conventional open surgery, but the postoperative drainage was significantly greater in thoracoscopic surgery than in open surgery. In view of the higher operational difficulty and surgical risk of laparoscopic lumbar interbody fusion surgery and more surgical complications, laparoscopically assisted small-incision anterior surgery, which is not only less invasive and easier to perform, but also has a shorter operative time and lower complication rate, is the future direction of minimally invasive anterior lumbar spine surgery. Although biological advances have enhanced the effectiveness of fusion, there are still some drawbacks, such as limited motion and increased stress in the adjacent segment. For these reasons, the disc replacement being performed today is the most encouraging advancement. Although it is very difficult to design an artificial disc that exactly equals the properties of a natural disc, it is beneficial in that it reduces the source of infection, reduces instability due to degenerative discs, restores natural stress sharing, and restores spinal motion characteristics. Theoretically, artificial disc replacement can replace fusion, provide physiological motion of the spine, and delay degeneration of adjacent segments. The first lumbar disc replacement was performed in 1996 for painful disc herniations, and a variety of different artificial discs are now available. They are made of metal or elastic fibers, and more recently there is an artificial disc with an inner layer of polyethylene and an outer layer of peptide, which is then encapsulated with plasma, but the success of its fusion is still not fully proven. In addition, the literature shows that case selection, the morphology and size of the artificial disc and its position are crucial for the outcome. While previous reports have applied anterior open surgery for disc replacement, current endoscopic techniques can also be used for laparoscopic artificial disc replacement. prodisc has recently developed a second generation disc prosthesis that can withstand all limits of lumbar motion except axial motion, is slightly smaller in size than a normal disc, but can be placed through an anterior laparoscopic or small incision through a retroperitoneal approach. With the advances in modern spine surgery technology and the use of new biomaterials and instruments in clinical practice, more and more anterior spine surgeries are being replaced by posterior surgeries, and major spine surgeries that used to be done through anterior and posterior approaches are gradually being done in a single stage posterior approach. Due to the complex anatomy of the anterior spine and the greater surgical trauma and higher incidence of surgical complications, as well as the inherent limitations and risks of lumpectoscopic anterior spine surgery, in recent years, lumpectoscopic anterior spine surgery has been gradually replaced by lumpectoscopically assisted anterior or lateral anterior, posterior and lateral posterior minimally invasive spine surgery. In the future, anterior laparoscopic spine surgery will be used more often for combined laparoscopic-assisted anterior-posterior spine surgery, which not only takes advantage of the minimally invasive nature of the laparoscopic approach, but also avoids the drawbacks of complex operation, long operation time and high complication rate of simple laparotomy. With the development of 3D laparoscopic technology and the establishment of digital, intelligent and hybridized operating rooms, the future of minimally invasive spine surgery technology is bound to see even greater development.