I. Principles of analgesic treatment for cancer pain Pain is one of the major symptoms of cancer patients, especially those with intermediate or advanced cancer. Successful treatment of pain in cancer patients depends on the clinician’s ability to assess the existing problem, identify and evaluate pain symptoms, and formulate a comprehensive continuity of care plan. (i) Significance of cancer pain treatment Cancer pain may resolve with the cure of cancer or may persist as a complication of curative treatment. Although cancer pain is often regarded as a critical manifestation of advanced cancer, even if the patient’s condition is stable and the expected survival period is long, there are many possible causes of cancer pain throughout the patient’s treatment, which may affect the quality of the patient’s survival, as manifested in the following: 1. Physiological aspects: reduced functioning, decreased strength and endurance, nausea, decreased appetite, poor quality of sleep, or insomnia. 2. 2.Psychological aspects: limited pastime and entertainment, increased anxiety and fear, depression and distress, excessive consideration of physical pain and loss of self-control. 3.Social aspects: reduced social activities, reduced sexual function and emotion, change in appearance, increased burden on caregivers. 4.Spiritual aspect: aggravation of pain, change of thoughts, re-evaluation of religious beliefs. Cancer pain not only affects the quality of life of patients, but also patients often lose hope or even refuse treatment due to the appearance of pain, and when the pain is aggravated, patients may become depressed and even consider or take suicidal behavior. Therefore, for cancer patients, the development of reasonable treatment methods to relieve pain is the central goal of treatment, and this goal also means to prolong the survival of the patient as much as possible, make him/her as comfortable as possible and maintain his/her functional status as much as possible. (ii) Principles of treatment of cancer pain 1. Understanding pain as a somatic and mental experience The International Society for the Study of Pain definition of pain is described as “an unpleasant sensory and emotional experience associated with or described in terms of actual and potential tissue damage.” Pain can be understood as the recognition of the role of injury perception, which is determined by the interaction between sensory neural pathway activity and other factors. These other factors constitute neuropathic processes and psychological disorders. Evaluation of cancer pain requires careful analysis of the complex relationship between pain and psychological well-being. The term “total pain” encompasses pain caused by a variety of harmful physical stimuli, such as physical, psychological, psychiatric, social, and economic factors. As a clinician, it is important to trust the patient’s complaints of pain and to correctly assess the impact of pain and its role in the patient’s overall suffering. This assessment helps to build a relationship of trust with the patient. 2. Careful history and comprehensive examination to clarify the diagnosis and evaluate the cause of cancer pain Careful questioning of previous medical history and the process of cancer progression is very important for the correct understanding of pain. The history of pain-related illnesses must indicate the corresponding pain characteristics, as well as the patient’s response to previous treatments for the primary disease and pain treatment. A thorough physical examination, including a neurologic examination, is a necessary component of pain evaluation. On the basis of the initial diagnosis, a series of diagnostic tests are performed for factors that are not clear-cut, the scope of which should be appropriate to the patient’s general condition and the overall therapeutic goals. It is worth mentioning that the treatment of pain should be carried out at the same time as the diagnostic tests, as pain relief improves the patient’s compliance and reduces the discomfort caused by the tests. At present, pain in cancer patients is usually categorized into four types internationally: (1) pain directly caused by cancer; (2) pain related to cancer; (3) pain related to cancer treatment; (4) pain unrelated to cancer such as gout and arthritis that the patient originally had. From our recent survey, (1) (2) causes accounted for 78,6% and 6,0% respectively, (3) accounted for 8,2%, and (4) accounted for 7,2%, and 6,7% of the patients were suffering from pain caused by more than two causes. It is self-evident that for the pain caused by (1) (2) two reasons, anti-tumor treatment can relieve the pain to a certain extent, so the principle of treatment should be anti-tumor plus analgesic; while for the pain caused by (3) (4) two reasons need to carry out analgesic and other related adjuvant treatment. 3.Select or combine appropriate treatments for pain relief Cancer pain is a comprehensive treatment process, and most cancer patients may get satisfactory pain relief through a method that includes basic treatment, systemic analgesic therapy, and sometimes other non-invasive techniques (e.g., psychological or restorative conditioning). This therapeutic measure is sometimes only possible with the help of interventional anesthesia or surgery for some patients whose pain is difficult to control. Three-step analgesic therapy for cancer pain World Health Organization (WHO) three-step analgesic therapy refers to the following: according to the different degree, nature and cause of pain, the single and/or combined application of non-steroidal anti-inflammatory drugs represented by aspirin, weak opioids represented by codeine and strong opioids represented by morphine, together with other necessary auxiliary drugs, can make the majority of cancer pain patients (80-90%) obtain satisfactory relief. 90%) can obtain satisfactory relief. Analgesic drugs can be divided into non-narcotic analgesics (non-opioids), narcotic analgesics (including weak and strong opioids) and auxiliary drugs according to their mechanism of action and clinical application. (a) The basic principles of three-step drug administration 1, according to the ladder of drug administration: the choice of analgesic drugs should be based on the degree of pain from weak to strong in order to improve, unless severe pain, generally for those who have never been given analgesic treatment or not in accordance with the three-step analgesic method of treatment should be preferred to the non-opioid drugs, belonging to the first step of the three-step ladder, this kind of drug neither produces drug resistance nor physical dependence, used for mild to moderate pain. These medications can also be used as adjuncts to second- and third-step medications, depending on the need for analgesia. Since these drugs have gastrointestinal adverse effects and their toxicity increases with increasing doses, and have a “capping effect”, when the maximum recommended dose is used for a period of time, and the pain still persists without satisfactory relief, the second step of the ladder should be added or switched to, and a weak opioid should be added on top of a non-opioid drug, instead of switching to another non-opioid drug. other non-opioid medications. Second-step medications have important uses; they are easy to prescribe and are more acceptable to patients than, for example, morphine, resulting in a number of compounded formulations in the clinic, and the safe dose of weak opioids is often limited by the dose of other nonopioids in their compounded form that have a capping effect. Patients whose pain is not controlled or continues to increase, or who have moderate to severe pain at the time of presentation, should be moved to tertiary care, where they should be replaced with a strong opioid, or a non-opioid may be added at the same time, which increases the pain-relieving effect of the opioid and reduces the amount of opioid used. In addition, patients with special indications should be given additional drugs. 2, oral drug delivery: where possible, strive for oral and other non-invasive and low-risk methods of drug delivery. This method is convenient, economical and scientific, not only can eliminate the discomfort of traumatic administration, but also can increase the patient’s independence; can cope with a variety of multiple pain; analgesic effect is satisfactory; side effects are small (to avoid medical infection, opioid analgesic oral administration of slow absorption, low peak value, not easy to produce drug dependence, so can be tolerated and dependence can be reduced to a minimum). Opioids are available in a variety of dosage forms; fentanyl transdermal patches or rectal suppositories of morphine are available if the patient is unable or unwilling to take them orally, and controlled-release tablets of morphine can also be administered rectally. Highly lipid-soluble drugs are suitable for sublingual administration. Parenteral routes of administration, such as intravenous, intramuscular, or subcutaneous injections, may be very effective for analgesia in some patients, but are often combined with significant toxic side effects. The injection itself can be painful and inconvenient, so it is not recommended as a routine route of administration. Alternatively, it can be accomplished with the help of an intravenous or subcutaneous injection device that is embedded in the body. Subcutaneous injection is similar to continuous intravenous infusion. 3, on-time administration: that is, in accordance with the prescribed interval, rather than on-demand administration, so that the next dose can be given before the disappearance of the previous dose, to maintain effective blood concentration, which can ensure continuous pain relief. Patients with persistent and recurrent pain should be dosed “on the clock”. For pain that occurs in the course of on-time administration (i.e., “eruptive pain”), a “rescue dose” of the drug should be given, and the choice of its type and dose should be made according to the three-step principle of gradual ascending, and the rescue drug should be given as a supplement to the regular medication, every 1~2 hours. As a supplement to regular medication, the rescue medication can be taken orally every 1~2 hours, or given by extra-gastrointestinal route every 15~30 minutes, on the basis of which the total amount of medication required for on-time administration can be titrated and adjusted according to the total amount of rescue medication dosage. Controlled-release tablets of morphine, which are currently in common use, generally reach peak plasma concentrations 3 to 5 hours after administration, with an effective duration of action of 8 to 12 hours. When fentanyl patches are administered for the first time, the effective concentration is generally reached at 6 to 12 hours, the peak concentration is reached at 24 hours, and the effect lasts for 72 hours. This makes it more convenient to administer the drug on time. 4.Individualized drug administration: individual sensitivity to narcotics varies greatly, so there is no standard amount of opioids. It should be said that any dose that relieves pain is the correct dose. The standard recommended dose should be determined and adjusted according to the degree of pain, previous use of painkillers, and pharmacological properties of the drug. If oral morphine, for example, its effective dose range from 5mg every 4 hours until the dosage of 1000mg, so the choice of opioids, should start from a small dose, and gradually increase until the patient feels comfortable. 5. Pay attention to specific details: patients with painkillers should be supervised and their reactions should be closely observed, aiming at minimizing the side effects while obtaining the best therapeutic effect. Adjuvant drugs can be used in any stage of the three-step treatment of cancer pain, in addition, it can also produce unique effect on special pain, but this kind of drugs except corticosteroid has a late effect, and generally takes effect after two weeks. (1) Corticosteroids: improve mood, anti-inflammatory activity, antiemetic, increase appetite, and reduce brain and spinal cord edema. Combined with opioids for brachial plexus and lumbosacral plexus pain. Also effective for liver metastases and visceral metastatic pulling pain, infiltrating soreness from head and neck, abdominal, and pelvic tumors, and distending pain from vascular obstruction. Combination with NSAIDs may aggravate adverse reactions. Pay attention to adverse reactions such as hypertension, hyperglycemia, weight gain, mental irritability during use. (2) Anticonvulsants: effective for nerve injury causing lacerating pain and burning pain, such as brachial plexus, sacral plexus, herpes zoster-induced pain, pain caused by extravasation of chemotherapeutic agents. (3) Antidepressants: increase the analgesic effect of opioids or direct analgesic effect, improve the mood of neurogenic pain effect. (4) NMDA receptor antagonists: NMDA receptors are closely related to the transmission and regulation of pain. Prolonged and continuous stimulation of the spinal cord in the NMDA receptor is activated, so that the spinal cord dorsal horn cells sensitized to all incoming stimuli have a greater response and produce persistent pain, while reducing the sensitivity to morphine drugs. NMDA receptor antagonists to block the process of the inhibition of central sensitization to improve the efficacy of morphine. They are also effective in refractory neuralgia. (5) Sedative and tranquilizing drugs: Sedative hypnotherapy also has a place in the management of intractable pain where other means are not effective. Through effective sedation, the pain and many symptoms of some patients can be satisfactorily relieved. The combined application of opioids and benzodiazepines, neuroleptics, barbiturates can have a sedative-hypnotic effect. Nerve block treatment for cancer pain The “three-step program” promoted by WHO in 1986 for the treatment of cancer pain has made a considerable number of cancer pain patients get effective treatment. However, there are some cancer pain patients who still have severe pain after strict application of “three-step program”, or are unable to accept the treatment of “three-step program” due to inability to eat, contraindication to medication, inability to tolerate analgesic drugs, and so on, and are in urgent need of other methods to alleviate cancer pain. These cancer pain patients who cannot accept the Three-Step Program or whose treatment with the Three-Step Program is ineffective account for about 10% to 20% of all cancer pain patients. There are many types of neurodegenerative treatments available for the treatment of intractable cancer pain, especially for patients with advanced colorectal cancer pain, which can basically satisfy their analgesic needs. Clinical indications and treatment methods should be rationally selected on the basis of accurate assessment. (I) Abdominal plexus block 1, Indications Abdominal plexus block can effectively treat epigastric pain caused by malignant tumors, especially the pain triggered by periaortic lymph node enlargement stimulating the abdominal ganglion, and it can achieve a good therapeutic effect. It is not effective for pain mainly caused by lesions of the abdominal wall or bone; it should be used with caution for activity-induced pain and when accompanied by ascites. This method can theoretically achieve a 6-month therapeutic effect if nerve-destroying drugs are used. Therefore, it is ideal for patients who can be discharged from the hospital and can go home temporarily. 2, Clinically relevant anatomy Upper abdominal visceral sensation begins in the peripheral nerves of the visceral organs and ends in the dorsal root nerves of the T5~T12 spinal nerves in the thorax via the large, middle, and lowermost visceral nerves of the abdominal plexus upward. Historically, sympathetic nerves were discovered earlier, and it is generally believed that the ganglia and plexuses of the abdomen are composed of sympathetic nerves; in fact, most of them contain parasympathetic nerves. Afferent fibers exchange neurons in the abdominal ganglia or in other small ganglia, whereas efferent fibers do not exchange nerves in the ganglia and form visceral neurons directly. The celiac plexus consists mainly of the right and left celiac ganglia located anterior to the abdominal aorta at the level of T12 ~L1. as well as a collection of several smaller ganglia, around which are formed the superior mesenteric artery plexus, the phrenic plexus, the renal artery plexus pararenal plexus, and others. Because of the wide range of ganglia and plexuses associated with pain in the abdominal organs, it is impossible to block each of them in the same space. Segmental blockade of the thoracic sympathetic nerves on both sides can theoretically achieve the purpose of inhibiting visceral pain but the method is quite complicated and cannot be practically applied yet. It is generally believed that abdominal plexus block at the level of visceral nerves has the best effect. 3. Operation technique The main treatment object of this method is patients with malignant tumors. Therefore, the possibility of the existence of tumor and the variation of the position of organs in the direction of needle entry should be fully considered. At the same time, it is necessary to refer to the spinal photographs at the T12~L2 level and the CT and MRI photographs of its surrounding tissues that have been taken in the last 2~3 weeks. The methods used for abdominal plexus block vary with the level of visceral pain to be blocked. They can be broadly categorized into two types: those that aim to block the celiac ganglia directly and those that aim to block the visceral nerves as well as the celiac plexus by infiltrating the abdominal aortic peripheral exams with a wide range of drugs. The choice of method depends mainly on the operator’s conception of the block, and there is no significant difference in the therapeutic effect. From the point of view of operational safety and simplicity, this article will focus on the latter. The abdominal viscera is a huge reservoir of blood, and the block can cause vasodilation and a drop in blood pressure. Hypovolemia often occurs, especially in patients who are unable to eat normally. Therefore, venous access must be established before blockade. The patient is placed in the lateral position, the L1 vertebra is found under X-ray fluoroscopy, and a marker is used to make a surface marking of the line connecting the upper edge of the foramen magnum and the center of the anterior edge of the vertebral body, which is slightly off the cephalad side (line 1). The 12th rib was then palpated and marked at its inferior margin (line 2). The puncture point was between the ribs and vertebrae, with the wide part taken at 7-8 cm from the median on line 1, and at the intersection of lines l and 2 in the narrow part. After disinfecting the skin, local anesthesia was performed with 1% lidocaine, and the needle was introduced from the lateral aspect of the vertebral body with a 2lG block needle with a needle core. All operations were performed under fluoroscopy. Ideally, the needle should reach the vertebral body near the center when viewed laterally. Next, the core is removed, a glass syringe containing saline is attached, and the needle is inserted according to the principles of the epidural resistance loss method. The syringe resistance suddenly disappears as the tip of the needle passes through the periosteal tissue into the space formed by the diaphragm and the large intervertebral artery. A mixture of 8 ml of Onepac 300 (contrast agent) and 2 ml of 10% lidocaine was used for imaging, and the spread of the fluid was observed. After 20 min to confirm that there was no abnormality, the operation was completed by injecting 15-20 ml of 99, 5% alcohol. Considering the possibility of a drop in blood pressure after the block, the infusion of fluids should be continued during the operation. After returning to the ward, keep the original position for 1 h, and then change to the free position and rest quietly for 2 h. 4. Complications and their countermeasures (1) postural hypotension As mentioned before, hypotension will occur after the block. Some patients also complained of dizziness when standing up immediately after the block. Therefore, it is generally necessary to lie down for a few weeks after treatment, and when it is necessary to stand up, you should sit on the bed for a few minutes before getting out of bed. (2) Diarrhea Mostly due to parasympathetic hyperfunction after sympathetic nerve block, but also lasts for more than a month, and can be treated symptomatically with antidiarrheal drugs. (3) Intoxication Abdominal nerve blockers contain more alcohol, and patients with poor tolerance to alcohol may become intoxicated. Alcohol dilates blood vessels can cause a decrease in blood pressure, and fluids should be given if necessary. (4) Alcoholic neuritis Abdominal nerve blocks can sometimes be accompanied by intercostal neuritis. It occasionally occurs in lumbar nerve injuries caused by luminal abnormalities. It can be treated symptomatically with anti-inflammatory and analgesic medications, and the intercostal nerve block can be used if necessary. Acute symptoms may last for 1 to 2 weeks and may be followed by prolonged numbness. (5) Vascular injuries In order to penetrate the abdominal plexus, the needle tip is often driven into the anterior vertebral body, occasionally puncturing the main abdominal artery. During the abdominal plexus block across the abdominal aorta and the posterior pedicle approach to the posterior aspect of the aorta, the needle should be withdrawn as soon as it strikes the abdominal aorta. Good hemostasis during puncture of the abdominal aorta and puncture of the great vein, among other conditions, do not cause fatal injury. (6) Retroperitoneal hemorrhage Our department met a patient with renal vascular injury aggravated by abnormal coagulation mechanism. (7) Rare complications Some rare complications have been described in the literature, but they can be avoided by fluoroscopic and contrast methods. (1) Mistakenly injecting drugs into the subarachnoid space: it may occur from the beginning of local anesthesia, and the key should avoid the intervertebral foramen to enter the needle. ② paralysis: mostly caused by nerve-destroying drugs injected into the radicular artery, aorta, etc., can be avoided by contrast prediction. Spasm: caused by injecting local anesthetics and nerve-destroying drugs into the blood vessels when contrast is not performed. Pleural fluid: mostly caused by alcohol injection into the pleural cavity. ⑨ Kidney injury: the tip of the needle fails to remain tightly attached to the bone. ⑨ Celiac disease: the thoracic duct usually starts at the 2nd lumbar vertebra and attaches to the vertebral body just anteriorly and superiorly. The thoracic duct is usually not punctured as long as excessive lateral approach of the needle is avoided. (ii) Epigastric inferior plexus block 1. Indications Effective for pain from pelvic viscera. (1) Pain caused by malignant tumors: rectal cancer, bladder cancer, prostate cancer, uterine cancer, etc. are indications. When the scope of the lesion expands beyond the pelvic viscera or when the lesion spreads to the bones and other somatic extensions and causes pain, the effect of the new blocking method is not obvious. (2) Benign diseases Perineal pain caused by chronic prostatitis, chronic anal pain, menstrual irregularities caused by endometriosis, etc. are also indications for this method. (3) Identification of pain can be used for the identification of cardiac pain and visceral pain. Clinically relevant anatomy The abdominal aortic plexus merges with the 2nd to 4th lumbar visceral nerves from the lumbar sympathetic ganglion between the beginning of the inferior mesenteric artery and the branches of the aorta. The combined plexus is the inferior epigastric plexus (presacral nerve). The inferior epigastric plexus contains not only sympathetic nerves, but also parasympathetic fibers from the pelvic visceral nerves, which innervate pelvic viscera such as the rectum, prostate, seminal vesicles, the posterior part of the bladder, the cervix of the uterus, and the vaginal vault. The inferior epigastric plexus descends along the abdominal aorta between the branches and the angle of entrapment, after which it divides into the right and left inferior epigastric plexus, which descends along the medial side of the internal iliac artery and enters the pelvic plexus. 3. Operational techniques (1) Lateral vertebral method The lateral vertebral method can be used either in the prone position according to PIancarte’s original method or modified to use the lateral position. When using an x-ray device, x-ray fluoroscopy in the prone position is used to observe the degree of proximity of the needle tip to the vertebral body. This proximity can also be determined by the sensation of the tip of the needle touching the bone. In the lateral position, fluoroscopy focuses on the position of the tip of the needle in the anterior-posterior direction of the vertebral body. If this lateral fluoroscopic image is combined with the degree of proximity to the vertebral body felt by the tip of the needle, the 3-dimensional positional relationship between the vertebral body and the tip of the needle can be clarified. From the above characteristics, the lateral position under fluoroscopy is more favorable, so we generally use the lateral position. Fluoroscopy table to the affected side (blocking side) on the top, take the knee slightly flexed side lying value. In thinner patients, an abdominal pillow is placed so that the fluoroscopic table is parallel to the spinous process. The bulb is then tilted in line with the vertebral plate. Starting from the anterior end of the spinous process of the 5th lumbar vertebra, a parallel line is drawn 8-10 cm outward from the spinous process. The larger the patient, the more outward the puncture point. The position of the 5th lumbar vertebra is confirmed under fluoroscopy, and the intersection of the line that passes through the cephalad side of the transverse process to the center of the anterior border of the vertebral body and the parallel line of the spinous process is taken as the puncture point. If the iliac crest obstructs the needle entry, the puncture point is deflected cephalad laterally. The puncture needle is a 2l~22 G/12 cm or 15 cm block needle. A 12 cm needle can be used for patients with standard body shape. Local anesthesia was administered from the above puncture point, and local anesthesia was performed under fluoroscopy with a Cattelan needle from the cephalad side of the transverse process of the 5th lumbar vertebra in the direction of the anterior margin of the vertebral body at the central portion of the vertebral body, one level at a time. The Cattelan needle was left in place and the syringe was removed. Using the Cattelan needle as a guide, the block needle was stabbed in the same direction. The ideal position of the needle is to contact the bone surface from the lateral image, from the side of the resident vertebral body to the anterior curvilinear change (anterolateral margin of the vertebral body). If the point of insertion is too far medially, the needle will touch the lateral aspect of the vertebral body. If the needle is re-entered from this point, the tip of the needle leaves the cone. When the tip of the needle touches the back of the vertebral body, or when the needle is seen to have reached the anterior 1/3 of the vertebral body and has not yet touched the bone surface, the needle is withdrawn for 4-5 cm and then the direction of the needle is changed to perform the puncture. In the lateral position, it is usually necessary to adjust the patient’s position in order to obtain an accurate lateral image, so that the left and right 12th rib shadows overlap under fluoroscopy. However, when the tip of the needle is difficult to reach the anterior side of the vertebral body, or when the operator has not yet mastered this method, the patient should first use lateral fluoroscopy, gradually tilt the body forward, and gradually find the anterior edge of the vertebral body to become the outermost angle. At this point, the outermost part of the vertebral body becomes the point of contact between the tip of the needle and the bone surface on the fluoroscopic image. As a result, the tip of the needle will not touch the vertebral body and cannot be advanced, and the number of cases in which the tip of the needle leaves the vertebral body by crossing the lateral side will be reduced. In addition, this method makes it easy to align the direction of needle insertion with the tangential direction of the anterolateral margin of the vertebral body. After touching the bone surface at the anterolateral margin of the vertebral body, the cartridge is removed, a saline-filled 5-ml syringe is attached, and the needle is inserted anteriorly with constant pressure. When the tip of the needle reaches l cm from the vertebral body, resistance is felt to disappear. This is the anterior aspect of the psoas major fascia, which is located in the posterior peritoneal cavity. Local anesthetics and nerve-destroying drugs were injected: 8 m1 of water-soluble contrast medium and 2 m1 of a 10% lidocaine mixture were used for contrast. The amount of drug needed to cover the 5th lumbar vertebrae anteriorly and spread to the sacral promontory was determined by lateral and frontal images, and the contrast medium was confirmed to be located in the median position by frontal images. After 20 minutes of observation and confirmation of no abnormality, the same amount of 99.5% ethanol was injected to complete the block. The amount of ethanol required is usually about 6-8 ml, and the effect is evaluated, and the contralateral plexus is blocked in the same way if there is still pain on the contralateral side. The operation may cause hypotension, so close observation is required. Rest in the original position for l h and then in the free position for 2 h. The inferior mesenteric plexus receives fibers from the 1st-3rd lumbar visceral nerves that continue from the abdominal aortic plexus. This plexus is at the height of the 3rd lumbar vertebrae, distributes to the colon and urogenital organs, and is associated with visceral pain in the lower abdomen. The inferior mesenteric plexus block is performed at the 3rd lumbar vertebra in the lateral approach to the vertebrae described above. The plexus is punctured 8-9 cm lateral to the spinous process through the caudal aspect of the transverse process of the 3rd lumbar vertebra in the direction of the central anterior margin of the vertebral body. It is preferable if a contrast image of the flow along the abdominal aorta can be confirmed. (2) Transintervertebral disc method A method of advancing the block needle through the disc toward the anterior median of the sacrum. If the tip of the needle is accurately positioned, a single puncture can obtain the effect of drug diffusion to both sides. In principle, the prone position is used, but the lateral position can also be performed. The 5th lumbar quasi and lth sacral vertebrae are confirmed under fluoroscopy. Connect the most lateral point of the inferior margin of the 5th lumbar vertebra with the median point of the ventral superior margin of the lth sacral vertebra. Extend this line laterally, and the intersection with a parallel line drawn 5-6 cm lateral to the spinous process is the puncture point. The same blocking needle as in the lateral vertebral approach was used. Local anesthesia was applied to the puncture point. The block needle was inserted under fluoroscopy toward the outermost part of the inferior border of the 5th lumbar vertebra, slightly to the medial-caudal side. The tip of the needle reaches the intervertebral disc, the cartridge is removed, a saline-filled 5 ml syringe is attached to the block needle, and the needle is continuously pressurized and slowly advanced toward the midpoint of the ventral superior margin of the 1st sacral vertebra. When the tip of the needle passed through the intervertebral disc, the resistance was clearly eliminated. The needle was advanced a further 5 mm to confirm that the tip of the needle was centered anteriorly in the sacrum. Imaging was performed with a mixture of 4 m1 of water-soluble contrast agent and l ml of 10% lidocaine. Orthostatic and lateral images were used to confirm the location of drug diffusion and to determine the amount of drug required. Orthostatic images were used to confirm that the contrast agent reached the median. After 20 min of observation after injection and confirmation of no abnormality, the same amount of 99, 5% ethanol was injected to complete the block. (3) Comorbidities and countermeasures ① Hypotension The blood pressure is lowered by the vasodilating effect of alcohol. (2) Intoxication A state of intoxication may occur in a patient who is intolerant to alcohol due to the use of a large amount of alcohol. ③ Vascular puncture From the anatomical positional relationship, it is more likely that the iliac artery will be mistakenly punctured by the lateral vertebral method. When the tip of the needle is in the arterial wall, resistance is generated and saline injection cannot be performed, in which case the tip of the needle should be withdrawn to a non-resistant position. When the needle tip touches the 5th lumbar nerve root, it may cause radiating pain, in which case the puncture point and direction should be changed. Nerve injury can cause pain and paralysis for several days, but most of them can be recovered without special treatment. ⑤ Dysfunction Although there is no clear report of dysfunction, there are reports that ejaculatory disorders can be caused by removal of the lower abdominal nerve. Especially in the case of malignant tumors, dysfunction is easily caused by pre-existing diseases and requires special attention. (C) Lumbar subarachnoid nerve block 1. Indications Lumbar subarachnoid nerve block is mainly used for the treatment of pain from malignant tumors originating from l~3 spinal cord segments and ineffective for other conservative treatments. Because of its serious complications, this technique is rarely used for the treatment of chronic benign pain, but may be considered after a careful risk-benefit evaluation of the patient. Because the technique is most effective for pain confined to a few spinal nerves, it is most often used in the treatment of pain involving the lower extremities and lower back, such as pain caused by tumor invasion of the lumbar plexus or metastatic I-generation prostate rectal malignancies. The lumbar subarachnoid nerve block destroys only the sensory component of the spinal nerve root while preserving its motor component, a feature that permits the technique to be applied to patients with an earlier course of disease. Used in conjunction with an iliac plexus block, lumbar subarachnoid blocks are more cost-effective than chronic intraspinal injections of morphine-like drugs. Clinically relevant anatomy Bell-Magendie’s law: motor nerve fibers are located ventral to the spinal cord, while sensory nerve fibers are located dorsal to the spinal cord. This anatomical basis makes it possible to selectively destroy sensory nerve fibers to preserve motor fibers at the same level. Unlike in the neck, the lumbar nerve roots emanate from the spinal cord at a much higher level than the level at which they exit the spinal column. Because the nerve block should be applied to the dorsal nerve root as it emanates from the spinal cord, the operator must specify the level at which the nerve emanates from the spinal cord in order to perform the block rather than the level at which the nerve exits the bony spine. The patient is placed in the dorsal nerve root up position, and a low-gravity nerve blocker, such as alcohol, is injected to anesthetize the sensory nerve fibers to relieve pain symptoms without affecting the motor nerves. With the patient in a supinated dorsal nerve root position, a high specific gravity nerve blocker can be used to block the sensory nerves to relieve pain symptoms without affecting the motor nerves. The lumbar spinal cord is protected by three layers of connective tissue: the dura mater, the arachnoid mater, and the soft spinal cord. The dura mater is in the outermost layer and consists of tough elastic fibers that protect the spinal cord as a mechanical barrier. The next layer is the arachnoid membrane, between which and the dura mater exists a narrow potential cavity filled with plasma. The arachnoid membrane is a barrier to diffusion of substances and can effectively prevent the diffusion of drugs injected into the epidural space into the cerebrospinal fluid. The innermost layer is the soft spinal membrane, whose vascular structures provide support to the spinal cord from the outside. Drugs injected into the subarachnoid space are deposited between the arachnoid and the soft spinal membrane, and accidental injection into the subdural space can occur. Subdural injections of local anesthetic are characterized by unstable, incomplete nerve blocks. In most adults, the lower spinal cord boundary is flat at the lumbar 2 vertebrae, but given that lumbar subarachnoid nerve blocks must be performed at the level where the nerves emanate from the spinal cord, spinal cord injuries caused by the puncture needle may still occur. 3, operation technique (1) Low specific gravity nerve block drug technique When lumbar subarachnoid nerve block is performed, the patient is usually in the lateral position. If it is difficult for the patient to lie on the side because of bone transfer or respiratory insufficiency, the patient can take the sitting position or semi-recumbent position. Although this position limits spinal rotation and facilitates the identification of midline structures, the potential dangers of the prone position, i.e., the difficulty of monitoring the patient and problems with airway management, should not be ignored and limit the routine use of the prone position in lumbar subarachnoid nerve blocks. As with local anesthesia techniques for other sites, proper posture is quite important for successful completion of the nerve block and avoidance of complications. Regardless of the position, careful positioning of the patient, identification of midline structures, avoidance of spinal rotation, and maximization of lumbar curvature are prerequisites for successful completion of the nerve block. The patient lies on his side with the lesion side up and his head is cushioned by a pillow to keep the lumbar spine flexed and not rotated. The patient is turned 45 degrees to the ventral side, and the chest and abdomen are cushioned in a comfortable position, which is maintained for 30 to 40 minutes to ensure that the puncture and nerve block are carried out smoothly. Locate the spinous process at the level of the spinal cord from which the pain nerve emanates. If the patient’s pain originates from a bone or deep structure, the raw bone table should be consulted to determine the innervating nerve in the affected area. The skin covering the spine of the diseased segment, as well as the skin above and below it, is sterilized, the spinous processes of the vertebrae of the diseased segment are identified, and the operator’s index and middle fingers are placed on either side of the spinous processes to reconfirm the position of the intervertebral space by rocking the upper and lower planes of palpation. The spinous processes above and below the intervertebral space were palpated using a transverse rocking maneuver to identify the midline of the selected intervertebral space. The most common reason for failure of subarachnoid nerve blocks in the lumbar spine is the inability to accurately identify the midline. At the midline point at the level of the selected intervertebral space, local anesthetic is injected into the skin, subcutaneous tissue, supraspinous ligament, and interspinous ligament beneath the ligamentum flavum. A 22G, 3.5-inch spinal puncture needle with a needle core is selected to accurately puncture the anesthetized area, the core is removed, and a 5 ml syringe containing saline is attached to the puncture needle, the piston of the syringe is pushed to maintain a certain level of pressure, and the other hand secures the puncture needle and the syringe, so that sudden movements of the patient will not cause the puncture needle to pierce the spinal cord. Using this “loss of resistance” technique, the epidural space can be identified. Once the epidural space has been located, if there is no blood or cerebrospinal fluid in the needle, the needle insertion is repeated and the needle is carefully used to puncture the dura and arachnoid membranes to enter the subarachnoid space. Care is taken to avoid uncontrolled maneuvers, which can result in spinal cord injury and subsequent possible development of spinal cord cavernous disease. Remove the core of the needle, observe that there is cerebrospinal fluid outflow, attach a syringe containing l ml of pure alcohol to the back of the puncture needle, and inject into the subarachnoid space in incremental doses of 0, 1 ml. Before the operation, the patient should be warned of the burning sensation for a few seconds after the injection and asked to indicate the site of the burning. The patient’s indication of the burning area will allow the operator to clarify whether the puncture is at or above or below the lesion and thus adjust the needle accordingly. This verbal feedback is important for the success of the lumbar subarachnoid nerve block, and because of this, it is not necessary to inject a local anesthetic through the puncture needle or to administer intravenous analgesia to alleviate the pain of the procedure. If the burning sensation after the injection of alcohol is consistent with the patient’s site of pain, inject a total of more than 0,8 ml of pure alcohol, and for each 0,1 ml injected, it is necessary to know its role and side effects. If the burning sensation is above or below the site of pain, remove the needle and puncture again, following the same procedure as before. It is not uncommon to block several nerves in order to relieve pain, but this should be done separately and will allow the patient to feel the relief of their pain and the effect of pure alcohol on their function. At the end of the injection, the needle was rinsed with 0,1 ml of sterile saline and the puncture needle was subsequently withdrawn. The patient was kept in the operating position for 15 minutes before being transferred to the supine position. (2) Technique of high specific gravity nerve blocking drugs Phenol (6, 5%) glycerol solution is the most commonly used high specific gravity lumbar subarachnoid nerve blocking agent. The blocking process is the same as the aforementioned low specific gravity nerve blockers, except for the body position. In order for the high-gravity block to anesthetize the dorsal sensory fibers without affecting the ventral motor nerves, the patient must be placed in a 45-degree reclined position on the affected side, with the back down, and a pillow or other cushion may be used to keep the patient in this position for 30 to 40 minutes. As with hypogravimetric blockers, the operator adds the blocker gradually in doses of 0, 1 ml, during which time he asks about the effects and side effects of each dose. The biggest disadvantage of this operation is that the affected side is underneath, and the whole process is more painful than that of low gravity blockers. 4. Complications and countermeasures If the operations are performed carefully, especially in the placement of the patient’s position, the complications of lumbar subarachnoid nerve block can be greatly reduced. Even with the best technique in cervical subarachnoid nerve block, sensory-motor dysfunction may occur after the operation, so the possible complications of the operation should be explained to the patient and his/her family before the operation, so that the risks and benefits can be clarified. Lumbar manipulation is associated with a higher incidence of rectal bladder dysfunction than neck and upper chest manipulation. Sensory dullness may occur after a seemingly successful nerve block. Dullness generally indicates incomplete destruction of the innervating nerve at the site of pain, and if it persists, a second nerve block may be considered. Local infection and sepsis are absolute contraindications to cervical subarachnoid nerve block due to the potential for hematogenous dissemination along the Batson venous plexus. In contrast to transcaudal access to the epidural, anticoagulant status and coagulopathy are absolute contraindications to subarachnoid nerve block in the lumbar spine because of the risk of epidural and subarachnoid hematoma. Hypotension is a common side effect of subarachnoid nerve block and is caused by the complete sympathetic block that accompanies the maneuver; prophylactic intramuscular or intraventricular injection of vasospastic agents and fluid supplementation help to avoid this serious side effect. Other peripheral local anesthesia, such as lumbar plexus block, is more appropriate than cervical subarachnoid nerve block if it is confirmed that the patient is unable to tolerate hypotension due to other systemic conditions. The possibility of accidental placement of a puncture needle or catheter into the subdural space also exists. If this goes undetected, the block will be unstable and the nerve blocker may diffuse to other nerves. This problem can be avoided by the operator gently inserting the needle after it has passed through the dura with a slamming sensation. If this technique is used correctly, neurologic complications from injury are rare after lumbar subarachnoid nerve block. Direct injury to the spinal cord and/or nerve roots is usually associated with pain. If significant pain occurs during placement of the puncture needle, the physician should stop the procedure immediately and determine the cause of the pain to avoid additional nerve injury. Delayed neurologic complications are most often the result of chemical irritation of the spinal cord and nerve surfaces, and irritation of the spinal cord has been reported. This condition is mostly self-limiting, but must be differentiated from infectious spinal meningitis. Subarachnoid infections, although uncommon, can still occur, especially in immunodeficient patients with AIDS and tumors. Once an epidural abscess has formed, urgent surgical drainage is necessary to avoid spinal cord compression and irreversible neurologic damage. Spinal meningitis after cervical subarachnoid block requires treatment with antibiotic injections in the subarachnoid space. Early diagnosis and early treatment of infection is important to avoid serious life-threatening sequelae. (D) Fully buried injectable drug pump placement 1. Indications Fully buried injectable drug pump placement for epidural or subarachnoid (more commonly used) drug injection is suitable for the following: (1) cancer pain treatment for cancer patients whose survival is expected to be months to years; (2) partially benign chronic pain for which spinal injections are effective in the test, but not in the other methods; (3) test dose of injections into the subarachnoid space by the spasticity persistence with reduced spasticity episodes after baclofen. The advantages of the fully embedded injectable drug pump are that it has a lower incidence of infection than the in-tunnel catheter/medicine pump and, furthermore, the failure rate of the fully embedded injectable drug pump is lower than that of the in-tunnel catheter. The disadvantage of the fully-embedded syringe pump is that placement, injection and removal are more cumbersome than in-tunnel catheters/pumps. Also, fully-embedded pumps are more expensive than tunneled catheters/pumps, although the higher initial cost can be offset by the price of subsequent medications and supplies. Clinically Relevant Anatomy The epidural space is bounded superiorly by the fusion of the periosteum with the dural spinal layer at the foramen magnum and continues downward to the sacrococcygeal septum. The epidural space is bordered by the posterior longitudinal ligament at the anterior edge, the spinal column and ligamentum flavum at the posterior edge, and the vertebral roots and foramina on both sides. The epidural space is 3~4mm at the level of C7~T1 in the cervical flexion, and 5~6mm at the level of L2~L3 in the lumbar region.The epidural space consists of fat, veins, arteries, lymphatic vessels, and connective tissues. Epidural or subarachnoid catheters can be placed anywhere along the spine from cervical to caudal, although most subarachnoid catheters are placed below the level of the spinal cord. The patient can be placed in the sitting, lateral, or prone position. The choice of position depends on the patient’s ability to remain immobile for the 25-30 minutes it takes to place the catheter and pump. Since most procedures are performed in the outpatient setting, the most comfortable position should be chosen to minimize the use of intravenous analgesic or sedative medications. Since different types of drug pumps are placed differently, the method of placement should be carefully understood before the procedure. The skin area, including the subcutaneous tunnel and pump placement site, is sterilized, and a 17G Touhy needle is inserted into the epidural space or subarachnoid space at the predetermined location. A one-piece silicone catheter is then inserted into the epidural space along the Touhy needle. The silicone catheter can be damaged by high resistance as it passes through the needle lumen, and the lumen and electrode should be flushed with saline beforehand. After the catheter enters the epidural space or subarachnoid space, it is slowly inserted for 3-4 cm, and a 5-mm incision is made with a 15-gauge scalpel in the head and foot path, keeping the needle in place to avoid damage to the catheter. Care should be taken to completely separate the tissue around the tip of the needle so that the catheter can enter the incision completely when the tunnel former is inserted. If a subarachnoid catheter is placed, a purse-string suture should be placed prior to needle removal to minimize hydrocele formation due to leakage of cerebrospinal fluid into the subcutaneous pouch. The needle is then carefully withdrawn along the catheter to the outside of the skin, the catheter’s metal sleeve is withdrawn posteriorly, and the Touhy needle is withdrawn from the catheter. The drug pump was then connected to the distal end of the catheter, and the integrity of the catheter was checked by injecting a small amount of sterile saline through the catheter after the return suction was correct. If the catheter is placed in the epidural space, 5-6 ml of 1.5% lidocaine is injected into the epidural space in order to provide good segmental anesthesia for the next step of making the subcutaneous tunnel. This procedure avoids the painful local infiltration anesthesia for the creation of a subcutaneous tunnel. If a subarachnoid tube is placed, it is recommended that epinephrine be added to the local anesthetic drug for tunnel anesthesia. The subcutaneous tunnel former is shaped to conform to the lateral abdominal pattern. The skin is lifted with forceps and the tunnel shaper is inserted subcutaneously in a lateral direction. When the head end of the tunnel former reaches the exit point of the right upper abdomen, it is directed away from the patient’s body so that the end is pressed against the skin. The skin is incised at the head end with a scalpel, and the tunnel former is removed from the incision. The path of the electrodes is straighter at this point, reducing the chance of damage due to bending and snapping of the subcutaneous electrodes. The skin incision is extended along both ends of the tunnel former to accommodate the subcutaneous placement of the drug pump. The pump is freed from the end of the catheter and the catheter is sutured to the proximal bolt of the tunnel former, and the tunnel former and catheter are then pulled through the subcutaneous tunnel from the second incision. The subcutaneous capsular bag is carefully created with small curved blunt-tipped scissors, taking care not to damage the catheter. The pouch must be large enough to accommodate the pump or the skin around the edge of the pouch may be damaged, but not so large that the contents are turned over and cannot be injected properly. Care should be taken to stop bleeding after the subcutaneous bag is made to prevent hematoma formation or infection. After hemostasis is complete, the distal portion of the catheter is cut off and the pump is attached to the distal portion of the catheter. The pump is fixed to the catheter with a non-absorbable suture through the silicone sleeve, and then the pump is placed in the skin bag, taking care not to bend the catheter. The incision was closed with interrupted double; layer sutures, and the sutures were removed after 10 to 14 days.