50.What is percutaneous laser disc decompression? Percuta-neouslaserdecompression (PLDD) was first described by Ascher and Choy in 1987, and the first procedure was performed in Graz, Austria. The laser fiber is inserted into the working cannula of the disc and the laser energy is used to vaporize the nucleus pulposus to effectively reduce the pressure in the disc, while the herniated nucleus pulposus retracts and reduces the compression and irritation of the nerve roots by the nucleus pulposus. The laser is advanced and practical in the treatment of disc disorders, and the technology is developing quite rapidly. However, this technique is not performed under direct vision and requires more expensive laser equipment. 51.What is posterior microendoscopic disc surgery? Posterior microendoscopic disc surgery (microendoscopicdiscectomysystem, MED), the MED surgical system was first introduced and started to be used in China in 1997, and the significant advantage of this system is the integration of traditional open surgery and minimally invasive endoscopic techniques. This system has the significant advantage of integrating traditional open surgery and minimally invasive endoscopic techniques. It adopts traditional surgical approach, so orthopedic surgeons have certain advantages in learning how to use it, and it is easy to master. It is characterized by accurate positioning under the guidance of a “C” arm x-ray machine, an incision of only 1.6 cm, no extensive stripping of the paravertebral muscles, and only a small amount of biting off the lower edge of the vertebral plate to widen the plate space and completely preserve the posterior and middle spinal structures. This type of discoscopy is relatively difficult for extremely lateral or foraminal herniated discs, but is quite convenient for central disc herniation or nucleus pulposus free into the spinal canal, and allows for lateral fossa enlargement and resection of the posterior border of the vertebral body. In recent years, with the improvement of surgical techniques, the indications have been broadened, mainly: (1) lumbar disc herniation, prolapse and intradural free; (2) central disc herniation with cauda equina injury; (3) combined with lateral saphenous stenosis and limited spinal stenosis; (4) combined with posterior longitudinal ligament calcification or fibrocartilage plate ossification. Contraindications: (1) lumbar disc herniation combined with severe spinal degeneration and spinal instability; (2) multi-segmental posterior longitudinal ligament calcification and fibrocartilage plate ossification; (3) those who have undergone traditional open surgery and are estimated to have severe spinal canal adhesions. 52.What is plasma myeloplasty? Plasma myeloplasty is a cold melting and cutting technique, which uses radiofrequency energy (100Hz) applied to saline (Na+) to attract a large amount of Na+ around the head of the cavitation rod to form a plasma particle area, and the energy can also provide the direction of Na+ movement, so that it gets enough energy to impact and break the molecular chains (peptide bonds) between tissue cells and form elemental molecules and low molecular gases (O2, H 2, CO2, etc.). Compared to traditional thermal cutting (300-600°C) such as electrocautery and laser, the cold fusion process is a technique that breaks the molecular chains of cells at low temperatures (40-70°C), which results in the removal of a large amount of diseased tissue without causing irreversible damage to the surrounding normal tissue (bleeding, necrosis, etc.). Myeloplasty removes part of the nucleus pulposus and completes the remodeling of the nucleus pulposus within the disc, and uses a heating (about 70°C) technique to vaporize, contract, and solidify the collagen fibers within the nucleus pulposus, resulting in a reduction in the total volume of the disc, thereby reducing the pressure within the disc for therapeutic purposes. This procedure has the advantages of less invasive treatment, quicker effect, shorter hospitalization schedule and less patient pain. 53.What is the purpose of surgery for lumbar disc herniation? With the development of the disease, some patients with lumbar disc herniation inevitably face the problem of surgery. In particular, patients who develop cauda equina symptoms such as large and small bowel dysfunction or those who have failed long-term systematic conservative treatment should receive surgery in a timely manner to avoid irreversible nerve damage. In the United States, about 200,000 people undergo lumbar disc surgery each year, while according to the Orthopedic Society of the Chinese Medical Association, about 485,000 operations for lumbar disc herniation were performed in 608 hospitals in 14 provinces and cities in the last decade. So, what is the ultimate purpose of surgery? Is it that a lumbar disc herniation can be completely cured after surgery? When a lumbar disc herniates, the nerve fibers of the fibrous ring, posterior longitudinal ligament and dura are stimulated, causing low back pain; if the protrusion directly presses the nerve root, it causes radiating pain in the lower limbs; if the protrusion is huge and presses the cauda equina nerve below the plane, symptoms such as dysfunction of the bowels and urine and incomplete paralysis of both lower limbs will occur. There are many ways to operate on lumbar discs, the main purpose of which is to remove the mechanical compression and chemical irritation caused by the herniation and to eliminate or relieve clinical symptoms. Strictly speaking, surgical treatment, like non-surgical treatment, is symptomatic rather than “curative”. Surgery can neither restore the lumbar region to its pre-onset state nor halt the process of lumbar degeneration. In this regard, patients who are ready to receive surgical treatment should have sufficient understanding. 54.What are the indications for surgical treatment of lumbar disc herniation? (1) Patients whose symptoms of lumbar pain are not relieved after conservative treatment. (2) Patients who have a first attack or recurrence, but the pain is so severe that the patient cannot tolerate it, or who have urinary or fecal disorders. (3) Patients with recurrent symptoms that cannot be eliminated for a long time and affect their work and life. (4) Patients who have obvious symptoms of nerve root compression, resulting in nerve root function damage. (5) Patients with central type herniation or suspected free block prolapsing into the spinal canal and producing cauda equina symptoms should be operated as soon as possible; patients with lumbar disc herniation accompanied by lumbar spinal stenosis or combined with lumbosacral “migrated vertebrae” or spinal slippage, who need to do lumbosacral fusion at the same time. 55.What preparations should be made before surgery for lumbar disc herniation? Once the decision is made to take surgical treatment for lumbar disc herniation, both the doctor and the patient need to be fully prepared for it. (1) The doctor should carefully study the patient’s condition and make a clear diagnosis based on the patient’s medical history, symptoms, clinical examination, X-ray, MRI, CT, imaging and other clinical data, and choose the best operation method. The patient and family members should also be fully informed of the various circumstances regarding the surgery. (2) Patients should be clear about the purpose of surgery and be fully prepared psychologically so that they can better cooperate with the medical staff and achieve the best results. (3) As with other major surgeries, preoperative cardiac, pulmonary, hepatic and renal functions and systemic conditions should be carefully examined, and local infection should be excluded. In addition, routine laboratory tests such as blood sedimentation should be checked. In general, there is not much bleeding during surgery, so the decision of blood preparation can be made according to the patient’s condition and the selected operation. (4) Local soap should be used to wash the surgical area before surgery to remove dirt. (5) For herniated discs above lumbar 3 or congenital developmental abnormalities of the lumbar spine, various means should be used to locate them before surgery. In conclusion, adequate preparation can improve the success rate of surgery. The preparation should not be neglected because the surgical methods for lumbar disc herniation are more perfect and mature, so as not to increase the chances of unexpected situations and various complications and affect the efficacy. 56.What are the surgical treatment methods for lumbar disc herniation? Traditional posterior lumbar disc removal Traditional posterior lumbar disc removal is still the most commonly used surgical method with reliable efficacy. The open window method, with less soft tissue separation, limited bone removal and less impact on the stability of the spine, can be used for most disc herniations. Half-laminectomy can be used for herniated discs combined with significant degenerative changes that require more extensive exploration or decompression. In cases of double herniation in the same space, or central herniation with tight adhesions that cannot be easily removed from one side, combined with obvious degenerative changes in the spine or combined with central disc stenosis requiring bilateral exploration and decompression, total laminectomy can be used. Care should be taken to preserve as many small joints as possible when removing the lamina. If the central disc herniation has obvious bone spur formation or the herniated disc is abnormally tightly adhered to the front of the dura, and it is difficult to remove it from the side, it can be removed through the dura. Extremely lateral lumbar disc herniation requires removal of the inferior articular process above the posterior intervertebral foramen or the application of the posterior lateral approach to expose and remove the herniated disc. In cases of combined nerve root canal stenosis or lateral saphenous fossa stenosis, the anteromedial portion of the articular eminence needs to be removed. If more than two synapses are removed, especially in young patients with discs and synapses removed in the same intervertebral space, fusion should be performed simultaneously. Traditional posterior surgery involves steps such as biting off part of the lamina or the whole lamina, removing the ligamentum flavum, removing the nucleus pulposus, and thoroughly stopping bleeding inside and outside the vertebral canal. The operation has an adequate exposure field, direct operation to remove the nucleus pulposus, and adequate nerve root decompression. However, after laminectomy, some patients form a large amount of fibrous scar tissue in the defective area of the lamina, or form irregular new bone, which adheres to the dura or nerve roots, causing secondary spinal stenosis and compression of the dural sac or nerve roots, causing recurrence of postoperative symptoms, which is called lumbar spine surgery failure syndrome (FBSS). Anterior surgery for lumbar disc herniation means that the surgery starts from the anterior side of the body, i.e. the abdomen, and enters the front of the lumbar spine layer by layer to remove the disc. The anterior approach was originally used through the abdominal cavity, but because postoperative gastrointestinal and digestive tract disorders such as intestinal obstruction can be caused, the extraperitoneal approach is now used more often: (1) The patient is placed in a supine position, and the site of the disc surgery is aligned with the kidney pad where the operating table can be elevated. (2) A median parietal abdominal incision of about 20 cm is made, and the rectus abdominis sheath is incised to expose the sacral angle by pushing the rectus abdominis muscle and the extraperitoneal fat and ureter to the sides, respectively. (3) There are nerve plexus and important blood vessels in front of the sacral horn. Exposure of the lumbar 5 sacral 1 vertebral space should be distal to the bifurcation of the abdominal aorta and inferior vena cava, and exposure of the lumbar 4 and lumbar 5 vertebral spaces needs to be over the external aspect of the common iliac artery and vein. The anterior longitudinal ligament is exposed by carefully pulling away the vessels, and the lumbar arteries and veins encountered can be ligated. (4) Fan the anterior longitudinal ligament and fibrous ring, turn them up, and expose the nucleus pulposus material. (5) Remove the nucleus pulposus and cartilaginous disc with a nucleus pulposus forceps and a scraper, from superficial to deep, until only the fibrous ring remains. The cartilage at the upper and lower margins of the vertebral body is removed with a bone chisel to expose the cancellous bone. (6) An incision is made in the iliac crest and the iliac bone block is taken according to the pre-determined dimensions for bone grafting. After shaking up the kidney pad of the operating table to increase the anterior opening of the vertebral body and inserting the bone graft, the kidney pad is flattened to reduce the anterior convexity of the lumbar spine, which can stabilize the bone graft in the vertebral space. (7) Suture the fibrous ring and anterior longitudinal ligament, and close the surgical incision layer by layer. Because of the fusion of the vertebral body, the patient should be strictly bedridden for 3 months after the anterior surgery, and should not be allowed to move on the ground until the intervertebral bony fusion is confirmed by radiographs. Anterior surgery is proposed in response to certain shortcomings of posterior surgery in practice, such as incomplete removal of the diseased disc, nerve root adhesions due to hematoma, and unstable spinal structures due to bone windows. Compared with posterior surgery, anterior surgery has its advantages and many shortcomings. Advantages of anterior surgery: (1) No damage to the back muscles and no involvement of the spinal canal. (2) The entire intervertebral space and cartilage disc can be well exposed and the diseased disc can be completely removed. (3) The discs of lumbar 4-5 and lumbosacral 1 can be treated simultaneously. (4) The bone graft maintains the width of the intervertebral space and can achieve bony fusion after disc removal. (5) It avoids damage to the intravertebral canal vein and its bleeding, and reduces scar formation in the spinal canal. It also deals with degenerative lumbar spondylolisthesis. The main disadvantage of anterior disc surgery: it is not possible to see the relationship between the intradural protrusion and the dural sac or nerve roots. The surgery is more traumatic than posterior surgery, and the postoperative recovery period is long. The transabdominal approach can damage the inferior abdominal plexus, which can cause sexual dysfunction and retrograde ejaculation in men, and may also damage the ureter and common iliac vein, which is more difficult to repair once damaged. Anterior transperitoneal lumbar discectomy anterior transabdominal approach for discectomy and bone grafting has certain advantages, but because of the need to enter the abdominal cavity, postoperative gastrointestinal and digestive tract disorders are likely to occur, and there are also postoperative intestinal adhesions. 57.What should I pay attention to after surgical treatment of lumbar disc herniation? The following points should be noted after surgery for lumbar disc herniation: (1) Patients need to take strict bed rest after surgery, and the bed should preferably be made with a hard board bed, and the bed rest time should be about 4-5 weeks. It can be determined according to the patient’s age, physical condition and the extent of resected tissue. (2) Early turning after surgery should be assisted by nursing staff and should not be turned strongly by oneself to ensure good healing of the lumbar fascia, muscles and ligaments. (3) After sufficient bed rest, you can be protected by a suitable lumbar girth. If there is a bone graft in the surgery, it is advisable to fix it with a plaster undershirt for 3-4 months, and wait for the bone graft to heal completely before moving to the ground. (4) During the recovery period, patients should gradually strengthen the exercise of low back muscle strength and pay attention to the correction of poor posture and self-protection of low back activities to prevent recurrence of disease. (5) After surgery, brain workers should gradually resume work after 2-3 months, and manual workers should start working only after 3-4 months. Work should be light to heavy, work time from short to long, and avoid doing strong bending into weight-bearing activities. 58.How to prevent the recurrence of lumbar disc herniation after surgery? To improve the efficacy of surgery, prevent the recurrence of lumbar disc herniation after surgery and avoid re-operation, we can start from the following aspects (1) Clearly diagnose before surgery, strictly grasp the indications for surgery, and make adequate preoperative preparation including positioning and formulation of surgical plan. (2) Promote the application of minimally invasive techniques and the selection of surgical procedures that cause little damage to the stability of the spine, such as unilateral opening of the vertebral plate, double opening, jumping opening, etc. (3) When removing the herniated disc, the lumbar spinal canal stenosis, lateral fossa and nerve root canal stenosis, etc. should be treated together. (4) Remove the gelatin sponge used for hemostasis before closing the incision, repeatedly flush with saline, aspirate tissue debris, and place a drainage tube. (5) Early postoperative straight leg raising activities and functional exercises of the lumbar back muscles were performed to prevent scar adhesions and increase spinal stability. Bed rest should be taken for at least 3 weeks after lumbar disc removal, timely management of early postoperative surgical complications, and avoid lifting heavy objects or participating in heavy physical labor for six months. 59.What are the reconstruction methods for lumbar disc herniation? (1) Artificial nucleus pulposereplacement (Artificialnucle-uspulposereplacement). The common types are metal type and organic elastomer type. The results of 20 cases of artificial nucleus pulposereplacement designed by the authors were reported in China. Except for one case that fell out, 19 cases were followed up for 2-7 years with excellent results and were able to maintain the preoperative height between vertebrae. The nucleus pulposus prosthesis was oval-shaped made of silicone rubber. The prosthesis is injected into the central part of the disc using a special injector through the popular posterior disc removal approach. Because of the small incision on the fibrous ring, the prosthesis is larger than the incision after restoring the round shape and is not easy to fall out. (2) Artificial lumbar disc replacement (Artificialdiscreplacement). Currently available for clinical use is the SBCharite type artificial disc designed by Buttner-Janz and Schell-nack in Germany in 1984. Why is artificial disc surgery not widespread? On the one hand, this indicates that the biological and biomechanical properties of the disc are complex and many are not yet understood; on the other hand, the development and research of material science, disc design and kinematics are yet to be improved. The main complications are: ①, dislocation of the prosthesis; ②, fragmentation of the prosthesis; ③, sinking of the prosthesis; ④, calcification of the fibrous ring; ⑤, malposition of the prosthesis; ⑥, nerve and vascular injury; ⑦, small joint pain. Complications can be divided into material and design factors, surgical factors and secondary lesion factors. (3) Homogeneous allogeneic disc transplantation. Domestic experimental studies on cryopreserved allogeneic disc transplantation were conducted by Dick Nguyen et al. The transplanted discs were preserved by gradient cooling to -196°C and surgically implanted after preoperative rewarming. The results showed no subluxation on X-ray, and 64.9% of the normal height was maintained at 24 months. There was only mild immune rejection in the area of the interface between the subplate bone of the transplanted disc and the host vertebral bone at 2 weeks postoperatively, which was more pronounced at 4 weeks, gradually reduced at 6 weeks, and gradually normalized at 8 weeks. Molecular biology showed reduced DNA content in the transplantation group. Cytokine gene fragments phIL-6, phIL-8, phTNF and iNOS were increased in the early stage compared with the control group, and the difference was not significant in the late stage compared with the control group. Biochemical results showed varying degrees of changes in the metabolism of both the nucleus pulposus and the annulus fibrosus of the transplanted disc. Biomechanical results showed a tendency to destabilize the transplanted disc in terms of rotation, horizontal and axial displacement in the early postoperative period, but had no significant effect on the overall lumbar spine activity, and stability was restored in all directions in the middle and late postoperative periods. It is also believed that disc transplantation has some clinical application prospects. (4) Gene therapy. The relationship between growth factors and disc degeneration and regeneration is one of the hot spots. Animal experiments have shown initial results in regulating the expression of certain growth factors through transgenic methods to promote the regeneration of the intervertebral disc extracellular matrix. It is believed that in the future, there is hope that it can be applied to human beings to achieve the purpose of slowing down the degeneration of intervertebral disc.