Pain is an unpleasant reaction of the organism to injured tissue or potential injury, a complex physiological-psychological activity, and one of the most common clinical symptoms.
It is also one of the common symptoms of patients with intermediate and advanced cancer, which is sometimes difficult to control and poses a great threat to patients. According to statistics, there are about 14 million cancer pain patients in the world, and about 7 million new cancer patients occur each year, 30% to 60% of which are accompanied by different degrees of pain. In China, there are more than 2 million cancer patients, and about 1.6 million new cancer patients occur each year. The incidence of pain is 40% to 50%, and 50% of the patients have moderate to severe pain, of which 30% have unbearable and severe pain. Cancer pain (cancer pain) affects patients’ quality of life from psychological, physical, spiritual and social aspects.
In the 1980s, the World Health Organization (WHO) put forward the goal of “making cancer patients pain-free” worldwide by the year 2000, but despite worldwide efforts, a large number of international surveys have shown that inadequate treatment of cancer pain is a common phenomenon, and controlling cancer pain is a global public health problem that cannot be ignored. The ideal goal of cancer pain control is
The ideal cancer pain control goals are
(1) good sleep at night.
(2) elimination of pain during quiet time
(3) elimination of pain during physical activity, with the ultimate goal of improving patients’ quality of life and survival. In the past, the concept of cancer pain management was that neurointerventional treatment was only considered when all other antinociceptive therapies failed to provide effective analgesia. However, in this state, the vicious cycle of pain has been formed, and most of the pain has evolved into intractable pain, and neurointerventional treatment is not fully effective.
Since neurointerventional treatment has the advantages of precise analgesic effect and does not directly affect the patient’s general state, consciousness level and mental activity, it should be intervened at the early stage of cancer pain treatment in a timely and appropriate manner, and should never be regarded as the last resort to combat pain when various therapies are ineffective. The new concept of cancer pain treatment believes that neurointerventional therapy, together with WHO three-step therapy and other antinociceptive treatments, can effectively improve the overall antinociceptive level, which is of great significance to improve the quality of life of cancer patients.
The expanded WHO three-step analgesic program also emphasizes the principle of multidisciplinary treatment and comprehensive control of cancer pain.
I. Basic principles of neurointervention
1.Patients should be given a detailed explanation of the analgesic principles of neurointerventional techniques and their analgesic advantages and disadvantages beforehand.
2. Carefully discuss the operation techniques, indications and possible complications of neurointerventional treatment.
3.The cause of pain should be clarified beforehand.
4.The use of imaging guidance, especially when making sympathetic nerve blocks or other special operations, is important for neurodestructive treatment.
5.Interventional treatment should be performed as early as possible in the pain, and should not wait until analgesic drugs, radiotherapy, surgery, etc. cannot be controlled.
6, should not rely solely on neurointerventional treatment to control pain, to focus on the combined application of medical, surgical and psychological treatment.
7, afferent nerve block pain, body nerve interventions are generally ineffective or minimally effective.
8.Physical or chemical neurointerventional techniques should be used as early as possible for sympathetic pain from the celiac plexus, inferior hypogastric plexus, and odd nerve ganglion to perform nerve destruction. However, for early sympathetic neuralgia, local anesthetics can be used for repeated blockade.
II. Basic indications for neurointerventional treatment
The indications for which neurointerventional treatment is preferred include
(1) Somatic neuralgia limited to several spinal cord segments.
(2) Sympathetically mediated thoracic, abdominal, and pelvic pain.
(3) sympathetically related extremity pain.
Destruction of the responsible nerve causing the pain completely aborts the pain within its corresponding innervation. For trunk and extremity pain caused by cancer invading the somatic nerves, physical or chemical destruction of nerve roots is more effective; for very limited trunk and head and neck somatic nerve pain, destruction of peripheral nerves is often effective; for sympathetic nerve-related extremity pain, sympathetic nerve block can mostly provide satisfactory analgesia. In addition, for sporadic cancer pain, intrathecal micro-morphine pump implantation can be considered as appropriate, and transsphenoidal pituitary block can also be used as appropriate.
For patients with cancer pain below the level of cervical 4 and with a prognosis of less than 1 year, transcutaneous spinal thalamic tractotomy (thermocoagulation) can be considered.
Contraindications of neurointerventional treatment
1.Patients and family members do not agree.
2.Patients with bleeding tendency, paying special attention to those in radiotherapy and chemotherapy.
3.Patients who cannot maintain a specific body position.
4.Patients with very poor general condition.
IV. Commonly used neurointerventional methods
(A) Spinal nerve intervention
It is a relatively simple method in neurointervention. The elderly and patients in poor general condition can be applied, but attention should be paid to the possible impairment of body function, especially motor function, which should be repeatedly explained to patients and their families in advance. The advantage of this technique is that it does not require particularly complicated medical equipment and can be carried out at the primary level. It can be repeated if the analgesia is not complete. The nature of pain is limited to somatic neuralgia, and the effect on visceral pain, discharge pain, and afferent nerve block pain is not satisfactory.
When there are more than 2 pain sites, the site with severe pain should be treated first; bilateral pain should be treated on the more painful side first, and then the opposite side should be treated 1 to 2 days later. When the primary pain is resolved, the original secondary pain will reveal itself and become the new primary pain, and the neurointerventional treatment can still be continued. Interventional methods can be performed by either physical or chemical methods. Strict asepsis is emphasized, and preoperative medication is not used as much as possible.
1.Subarachnoid spinal nerve posterior root destruction
Selective destruction of the posterior spinal nerve roots invaded by cancer is a relatively simple and effective analgesic method. Commonly used drugs include phenol glycerin and anhydrous ethanol, both of which have basically the same analgesic effect, and the choice of which one should be decided according to the experience and habits of the operator. Generally speaking, it is more convenient for beginners to use phenol glycerin. Accurate localization of the spinal nerve segment according to the site of pain and proper positioning of the patient during surgery are the keys to success.
The duration of analgesia and the occurrence of side effects are closely related to the amount of nerve fibers destroyed, and there is usually no permanent motor or sensory dysfunction if the site is correctly selected and the amount and concentration of nerve-destroying drugs are appropriate. After a period of time, as the damaged nerve regenerates, pain may sometimes recur, and nerve block treatment can usually be repeated. If the analgesic effect after the initial block only lasts for 2 to 3 days, a second block treatment is feasible. Regardless of the analgesic effect, generally no more than 2 nerve disruption treatments are performed.
In case of unsatisfactory results, the following possibilities should be considered in addition to the exclusion block technique itself.
(1) cancer infiltration or local inflammatory changes preventing the drug from reaching the target nerve root.
(2) Sympathetic pain, especially visceral abdominal pain requiring bilateral abdominal plexus blocks.
(3) Discharge pain caused by pathological fractures of the spine or other parts of the body, etc.
(4) Other, this therapy has incomplete analgesia in about 10-20% of patients. Common comorbidities include motor, sensory, and vesico-rectal sphincter dysfunction, which are mostly transient. Properly applied, serious complications are less likely to occur. In position, phenol glycerin block is applied in the half-lying position on the affected side and anhydrous ethanol in the half-lying position on the healthy side. For lumbosacral block to avoid vesicorectal dysfunction, a 45° semi-sitting position with tilt to the affected side may be used. When phenol glycerin is injected into the subarachnoid space, the patient may feel a warm sensation or an antidromic sensation within the innervation of the corresponding nerve root.
When the initial 0.2 ml is injected, the above sensation is deviated more than one spinal cord segment from the painful site, then the puncture should be repeated or the tilt angle of the operating table should be adjusted. When anhydrous ethanol reaches the corresponding nerve root, the patient has a transient sharp pain or burning-like sensation. These sensations should be fully explained to the patient preoperatively. Subarachnoid blocks at the level of the neck and upper thoracic spine are more effective with anhydrous ethanol than with phenol glycerin. It is particularly effective for pain in the chest wall, but is often less effective once the tumor has invaded the pleura and lungs. Dosage 5~7% phenol glycerin 0.5~1ml for cervical thorax, 0.5ml for lumbosacral region. 2ml of anhydrous ethanol.
2.Epidural nerve destruction
The epidural analgesic effect is generally inferior to that of subarachnoid, manifested by short analgesic period, poor analgesia, and no obvious unilaterality. The operation technique is basically the same as epidural anesthesia. Sacral canal block in head high position can selectively destroy sacral nerves 4 and 5, which can effectively control perineal pain and avoid bladder and rectal dysfunction. 5ml of 5% phenol water solution injected at T12-L1 level for epidural nerve destruction can effectively treat the burning pain and posterior sensation caused by rectal cancer.
3.Intervertebral foramen nerve root intervention technique
Physical or chemical methods can be used to perform responsible nerve destruction. It has significant effect on pain in single or several innervated areas caused by cancer compression, infiltration and destruction.
4.Peripheral nerve intervention technique
Interventional treatment of peripheral nerves in painful areas is effective for limited pain, although it cannot bring long-term pain removal effect. For example, intercostal nerve, terminal branch of trigeminal nerve, occipital nerve, etc. Local anesthetics and hormone preparations can also be injected into superficial and limited bone metastasis pain, which often leads to better results.
(B) Cranial nerve interventional techniques
The effect of cranial nerve interventions is often worse than that of spinal nerves. The reasons are.
(1) The nerve distribution is complicated, and the effect is incomplete with 1 or 2 nerve blocks.
(2) The enlargement and infiltration of the tumor will make the operation of craniofacial nerve block more difficult in the originally small geographical area.
(3) The distribution and function of the cranial nerves are unique and often limit the destructive treatment.
Commonly used interventions include: trigeminal nerve block, linguopharyngeal nerve block, vagus nerve block, superior laryngeal nerve block, etc. Physical or chemical methods are available.
(C) Sympathetic nerve interventional techniques
Some or all of the pain can be transmitted by sympathetic nerves. To correctly grasp the nature and scope of pain and to clarify whether it is sympathetic pain is the key to the success of sympathetic block.
The common types of sympathetic pain in cancer pain clinic are as follows.
(1) Burning neuralgia in diffuse surgical scar area, ipsilateral upper limb, axilla and shoulder after radical breast cancer surgery, swelling, bruising and burning pain in upper limb caused by upper chest tumor invading brachial plexus nerve or large blood vessels, etc. Cervical sympathetic nerve intervention is effective.
(2) Chest pain, upper limb pain and upper abdominal pain caused by lung cancer and malignant tumor metastasis can be treated with thoracic sympathetic ganglion intervention.
(3) Pain caused by tumors of pancreatic, hepatobiliary, gastric and other upper abdominal organs or metastatic cancer pain in the upper abdomen can often be completely controlled by abdominal plexus intervention. However, sometimes spinal nerve block is needed to achieve the best effect. If the tumor invades both the abdominal wall and the posterior peritoneum, it often manifests as deep pain in the upper abdomen and the belt of the lower back, and the effect of abdominal plexus intervention alone is not satisfactory. If combined with subarachnoid block, it can improve analgesia.
(4) For pain caused by tumors in the lower abdomen and pelvic viscera, lower abdominal plexus intervention is feasible.
(5) The lower limb lymphatic drainage edema and burning neuralgia caused by pelvic and pelvic visceral tumors can be relieved by lumbar sympathetic ganglion interventions.
(6) In situ anal pain or metastatic cancer pain in the anal region after rectal cancer surgery, interventional treatment of odd ganglion is feasible. Commonly used drugs include anhydrous ethanol, 5-7% phenol glycerin, local anesthetics, etc. In principle, the “anti-inflammatory and analgesic solution” prepared by local anesthetics plus glucocorticoids and vitamins is not used. Commonly used physical methods include radiofrequency thermal coagulation technology, etc.
Cancer pain is a complex pain syndrome, which requires not only comprehensive medical treatment, but also the cooperation of patients’ family members and their own psychological treatment to reduce the psychological burden, minimize patients’ pain and improve their quality of life. It is the most ideal requirement for clinicians, patients and their patients’ families to let patients spend a pain-free life within their limited life time.