How to coordinate the pain society with the pain group and how to deal with the relationship; whether the anesthesia professionals should carry out pain treatment and research independently or be affiliated with the pain society to carry out business and other issues are to be solved from the ideological understanding and organizational form. The organization of the pain department: anesthesiologists mainly, with neurological surgery, psychiatry and psychologists to form a comprehensive consultation unit, is now recognized as an ideal organizational form.
1.The main tasks of the pain department: diagnosis, treatment, prognosis judgment and scientific research of pain patients.
2.Definition of pain: the pathological abnormal state that occurs at the nerve endings and stimulates the conduction system to the brain, thus causing an unpleasant sensation, called pain.
3.The classification of pain can be divided into the following categories according to the location, cause and nature of the occurrence.
According to the origin of pain: somatic pain, pain in the limbs.
According to the cause: acute pain, chronic pain
According to the special nature of classification: radiated pain, involved pain
Common pain diseases
Advances in basic pain theory research
I. Central sensitization phenomenon and pain treatment.
That is, when C-fibers are continuously impulsed to injurious stimuli, the activity of the dorsal horn cells of the spinal cord increases and the response to peripheral nerves is enhanced. Neuropeptides (e.g. substance P, calcitonin gene-related peptide) with excitatory amino acids (L-glutamate, aspartate) are released to the dorsal horn of the spinal cord, causing changes in excitability and loss of inhibitory mechanisms. This leads to spontaneous pain, nociceptive hyperalgesia, enlargement of the pain area or persistent pain.
The clinical guidance of this theory is that the treatment of chronic pain should focus on relieving central sensitization.
The application of drugs that antagonize neuropeptides, such as dextromethorphan drugs (CP 9345) versus the application of drugs that antagonize excitatory amino acids (EAA), such as ketamine. Therefore, there are more studies in this area.
The role of nitric oxide in the mechanism of spinal pain regulation
It is believed that NO is closely related to NMDA receptor (excitatory amino acid receptor), so the role of NO synthesis before X in spinal pain regulation has attracted wide interest in recent years.
Third, the drug research of pain treatment
Opioids, non-steroidal drugs for the treatment of pain with a long history, but the problem is that non-steroidal drugs are ineffective for neuropathic pain, and opioids are not suitable for the long-term treatment of some chronic pain. Research on analgesics has been slow, mainly because the mechanism of chronic pain is unclear. It is only in recent years that a distinction has been made between chronic pain and acute reactions caused by injurious stimuli, offering hope for drug development.
1. Drugs that act on peripheral sites.
A. Inflammatory mediator inhibitors.
a. Bradykinin antagonist drugs: antagonists acting on BK-B2 receptors, such as WIN64338 has been produced.
b. Metabolite inhibitors of arachidonic acid: such as COX-2 inhibitors (currently in animal experiments)
c. Inhibitors of cell-mediated toxicity
B. Sodium channel modulators.
Applied to neuropathic pain, such as phenytoin sodium, local anesthetics anti-arrhythmic drugs.
2. Drugs acting on the central nervous system: neurokinin and neurokinin antagonists
a. Tachykinin antagonists: mainly for nociceptive sensitivity caused by substance P.
b. Calcitonin gene-related peptide: experimental stage.
c. Growth inhibitors: considered to be drugs that act on opioid receptors.
d. Cholecystokinin (CCK) antagonists
e. Glycopeptide agonist: thought to have a strong inhibitory effect on spinal cord dorsal horn conduction, and is expected to be called a new type of analgesic.
Advances in treatment
i. The so-called balanced analgesia and multimodal complementary analgesia: that is, combined analgesia.
The main idea is to use the additive and synergistic effects between drugs in order to provide adequate analgesia while reducing the dose and side effects of each drug.
II. Pre-analgesia and over-analgesia.
Third, the study of drug delivery routes.
Such as transdermal drug delivery; transmucosal drug delivery, such as oral, nasal and ocular mucosa (sufentanil is not irritating), etc.
IV. Stellate ganglion block therapy.
This method accounts for 50% of outpatient treatment in Japan. There is a wide variety of indications.
V. Application of laser in pain treatment
? Basic types.
Low-response laser therapeutic device and high-response therapeutic device. Commonly used are aluminum-gallium-arsenic semiconductor laser therapy.
? Indications.
Pain caused by various bone diseases, myofasciitis, herpes zoster pain, cancer pain, neuralgia such as: trigeminal neuralgia.
Principles of pain treatment and preparation
Due to the complex pathophysiological mechanisms of pain, many factors affecting pain, pain patients involve various clinical disciplines. Therefore, to improve the effectiveness of pain treatment, reduce the occurrence of complications and enable the smooth and healthy development of pain operations, three important principles must be adhered to.
One: First of all, a clear diagnosis must be adhered to, reflected in eight aspects.
1. clarify whether it is an indication for pain treatment.
2: To clarify the etiology and nature of the lesion.
Tumor – inflammation – injury – deformity.
First of all, we must exclude Tumor!!! Do not delay surgery
3.Define the tissues and organs where the lesions are located.
4.Define the lesion site and depth.
5.Define the structural changes in the lesion area: for example, for patients with radicular cervical spondylosis and atlantoaxial spine injury, define whether there is cone tilt, displacement, etc.
6.Define the urgency of the disease process.
7.Define the patient’s systemic status, organ function and drug allergy history.
8.Estimate the efficacy and prognosis: have a good idea, and be accountable to the family.
II. Comprehensive treatment, especially for chronic pain.
Ensure safe and effective (the first principle of pain treatment)
1, master the patient’s functional status of vital organs. Among the pain patients, 43.6% are over 50 years old, and there are also more elderly people and more concomitant illnesses.
2. Configure and prepare first-aid drugs and equipment.
3.Block therapy to prevent inadvertent entry into the subarachnoid space and blood vessels.
4, must be strictly aseptic operation, to prevent infection.
5.Familiarity with anatomy is a prerequisite for safe operation and avoidance of complications.
Fourth, the preparation of both doctors and patients
1, routine laboratory tests, electrocardiogram and blood glucose must be performed on patients over 40 years old before treatment.
2. Large invasive operations should be prepared for fasting.
3.It is necessary to prepare the mind for accidents.
4.Invasive operation should be explained to the family about the possibility of complications, and it is better to sign.
Clinical evaluation of chronic pain
1. time of attack
2. frequency of attack
3. aggravating factors
4. relief factors
5. nature of pain
6. Pain level
7. concomitant illnesses
8. previous treatment history
9. patient’s thoughts and desires
Clinical treatment of pain
Pain treatment sites of action.
? The site of action of NSAIDs and hormonal drugs in the peripheral region of the injurious stimulus injury.
? transcutaneous electrical stimulation acts on myelinated nerve fibers.
? sympathetic nerve blocks that block sympathetic pain transmission.
? the lateral spinal thalamic tract as the site of action of epidural hormones and anesthetics.
? The thalamus is the target site of opioid action.
? Psychotherapy interferes with the understanding of pain then at the cortical level.
? Tricyclics and other antidepressants affect the downstream conduction tracts that travel down to the posterior spinal roots, and they also act on the posterior spinal ganglia
Medication
Non-invasive pharmacotherapy.
Non-steroidal drugs
Non-steroidal anti-inflammatory drugs reduce the production of inflammatory mediators such as prostaglandins in injured tissues by inhibiting cyclooxygenase, thereby reducing the sensitivity of nerve endings to injurious stimuli and achieving pain control. They are particularly effective for pain caused by musculoskeletal damage.
Opioids
? Cancer pain.
The treatment is individualized for different patients according to the WHO three-step analgesic ladder.
? Non-cancer pain.
Weak opioids are used in principle, and a combination of nonsteroidal anti-inflammatory drugs is recommended.
Adjuvant analgesics
? Adjuvant analgesics are a class of drugs whose primary indication is not pain, but which can be used to treat certain pain. For some patients, adjuvant analgesics need to be taken together with traditional analgesics (NSAIDs and opioids).
? Indications: For pain that is not effective or ineffective with commonly used doses of traditional analgesics, or to reduce the dose of traditional analgesics and their side effects, and for the treatment of symptoms other than pain.
I. Corticosteroid drugs
Corticosteroids? These drugs have anti-inflammatory effects and reduce edema around tumors and abnormal tissues, thus achieving pain relief by reducing the pressure on nociceptive tissues. Recently, it has also been found that the local action of these drugs can reduce the conduction of normal unmyelinated C-fibers.
? Main indications: compressive and destructive pain associated with the central nervous system and peripheral nerves.
? Drug class.
Prednisone 40 to 100mg/day PO
Flumethasone 16～24mg/day PO, IV
II. Anticonvulsant drugs
? This class of drugs has the effect of inhibiting the automatic discharge of neurons.
? Indications.
This class of drugs is useful for the treatment of neurogenic pain, especially for
diseases with explosive pain, are of great importance.
? Commonly used drugs.
Carbamazepine 200-1600mg/day PO
Phenytoin sodium 300～500mg/day PO
Third, tricyclic antidepressants
Tricyclic antidepressants Tricyclic antidepressants reduce the reuptake of monoaminic neurotransmitters (norepinephrine and 5-hydroxytryptamine) in the presynaptic membrane and increase the concentration and duration of action of these transmitters at the synaptic site, thus promoting the effect of downward transmission inhibition of pain pathways.
? Clinical mechanism of action: Improves mood, enhances the analgesic effect of opioids, and has direct analgesic effects.
? Indications: Post-treatment neuralgia with psychosomatic disorders, diabetic neuralgia, arthritis, migraine, tension headache and cancer pain with chronic neuropathic pain and other chronic painful diseases with abnormal continuity of sensation.
? Commonly used drugs: Amitriptyline 25~150mg/day PO
IV. Psychosuppressants
? This drug includes strong tranquilizers for the treatment of psychosis and other mental disorders, and its mechanism of analgesic effect may be through the inhibition of a-adrenergic effects.
? Indications: Mainly for the treatment of cancer pain. Since it does not inhibit gastrointestinal motility, the analgesic effect can be achieved by switching to such drugs for those patients who have developed resistance to opioids or when the application of drugs is limited by side effects such as intractable constipation.
What is the most common drug? Commonly used drugs: Methoxsalazine
It is the only drug of phenothiazine with analgesic effect (10~20mg = 10mg morphine)
V. a-2 adrenergic agonists
? These drugs are multifunctional analgesics. The mechanism of action is not fully understood, but it is presumed that a-2 adrenergic receptors act on the channels of non-adrenergic pain regulation system in the central nervous system. The mechanism of analgesia for persistent pain may lie in the inhibition of central sympathetic nerves.
? Indications: chronic headache, chronic neuralgia, cancer-related neuralgia, non-neuropathic and non-malignant pain syndromes, etc.
? Commonly used drugs: Colistin
VI. Capsaicin ointment
? The drug is the active ingredient in chili peppers. It can deplete the small peptides in the efferent neurons, including P-substance, thus effectively relieving the neuropathic pain in some patients.
? Indications: mainly for neuropathic pain, such as post-treatment neuralgia, post-mastectomy neuralgia, etc.
? Commonly used method: 0.025% ointment, applied to the painful area 3~4 times a day, the course of treatment for at least 4 weeks has the best effect.
VII. Benzodiazepines
The effect of benzodiazepines Mechanism: Enhance GABA receptor agonism, so that the transmission of GABAergic neurons increased
? Indications: Pinprick-like or paroxysmal neuropathic pain syndrome, chronic neuropathic pain in cancer patients, muscle spasm produced in the vicious cycle of pain.
? Commonly used drugs: clonidine – paroxysmal neuralgia
Alprazolam – cancer neuralgia Valium, etc. – to reduce muscle spasms
VIII. Bisphosphonates and calcitonin
? These drugs are commonly used for severe bone pain caused by bone metastases from cancer and increased osteoclast activity leading to bone resorption. Bone resorption also causes osteoporosis, hypercalcemia and pathological fractures.
? Bisphosphonates and calcitonin inhibit bone resorption and hypercalcemia, thereby reducing bone pain and decreasing the amount of analgesics.
Invasive treatment
? Invasive drug therapy
? Invasive non-pharmacological treatment
I. *Nerve block and injection techniques (1)
1.Peripheral nerve block: By blocking the nerve with local anesthetics and hormones, it can make an effective differential diagnosis of the source of irritation of the disease and also reduce the nerve edema caused by inflammation.
2.Epidural hormone injection: mainly used in patients with back and limb pain caused by nerve root inflammation or irritation. Hormone injections can be combined with local anesthetics.
*Nerve block and injection techniques (2)
1.Selective nerve root injection: X-ray localization is used to block the affected nerve roots, and a very small amount of local anesthetic and hormone can achieve effective analgesia.
2.Small joint block of the spine: using X-ray positioning, small joints of the cervical and lumbar spine can be blocked, which is often very effective for pain caused by degeneration of small joints of the spine.
3.Denervation of small joints: Generally, radiofrequency or freezing technology is used to cut the nerves that innervate small joints, which is suitable for prolonged and persistent pain.
*Nerve block and shot therapy (3)
Methods Indications
? Pain provoking point injection Myofascial pain
? Somatic nerve block Nerve root pain, scar pain
? Trigeminal nerve block Trigeminal neuralgia
? Venous regional sympathetic Reflex sympathetic dystrophy
Block (quebracho) Good, sympathetic maintenance pain
*Nerve block and injection therapy (4)
Methods Indications
? Stellate ganglion block Reflex sympathetic dystrophy
benign, sympathetic maintenance pain
? Lumbar sympathetic block Circulatory insufficiency, ischemic
rest pain, reflex sympathetic dystrophy, sympathetic maintenance pain
sympathetic dystrophy, sympathetic maintenance pain
sympathetic maintenance pain, phantom limb pain, amputation
Stump pain, malignant pelvic pain
*Nerve block and injection therapy (5)
Methods Indications
? Abdominal plexus block Intra-abdominal malignant pain
? Epidural hormone therapy Benign, or malignant nerve root
pain
II. Implantable intradural drug therapy pump
This method is effective in the treatment of peripheral pain such as bone pain, and is characterized by.
* Selective, regional peripheral continuous analgesia.
*The opioids can be used in small doses and with high efficiency, significantly reducing the side effects of the drugs.
Third, nerve destruction surgery (1)
? Radiofrequency (thermal) and freezing (cold) techniques (temperature neurotomy)
Advantages.
a non-invasive, fast recovery
b The location of the injury can be controlled
c Accurate localization is possible through electrode testing of movement and sensation
d Operation can be performed under local anesthesia
e safe, low incidence of accidents
Indications.
a chronic lumbosacral and small joint-derived pain in the neck
b intervertebral discogenic low back pain
c Radicular pain
d Sacroiliac joint pain
e sympathetic maintenance pain syndrome
f Cervicogenic headache
g trigeminal neuralgia
*Nerve destruction (2)
? Nerve destruction and dissection
(mainly for malignant pain)
* Intraspinal drug neurodesis
* neurodesis
* Pituitary resection (widespread pain due to generalized tumor pain)
* Anterior cervical medullary column dissection (unilateral somatic nerve malignant pain)
IV. Stimulation-induced analgesia (1)
Method Indications
? Spinal cord electrical stimulation Neuropathogenic pain, such as intractable
persistent low back pain, reflex peripheral
peripheral neurodystrophy, adhesive
arachnoiditis, phantom limb pain, and
Ischemic or vasculogenic pain
*Stimulation-induced analgesia (2)
Methods Indications
Stimulation-induced analgesia Transcutaneous electrical nerve stimulation Various skeletal-muscular pain, pain of
neuropathogenic pain, postoperative
pain, etc.
? Acupuncture techniques neurological and musculoskeletal pain
(combined with electricity, heat and manipulation)
V. Biofeedback therapy (1)
Biofeedback therapy has a therapeutic effect on some clinical chronic pain states. It is believed that the subconscious psychological response or physiological response directly affects the occurrence of chronic pain, and controlling this response will help to reduce pain. Biofeedback methods mostly involve measuring indicators of physiological function, such as body temperature or muscle tone, which change through the patient’s self-regulation, thus enabling the patient to master pain reduction.
*Biofeedback therapy (2)
In clinical cases such as low back pain and chronic headaches, abnormal muscle contractions often cause or exacerbate these pain syndromes. By using biofeedback methods, patients can know the muscle tone in this abnormal state. When the patient masters the method of controlling abnormal muscle tone, the pain is reduced.
Neuropathic pain syndromes
Reflex sympathetic dystrophy RSD, burning pain CAUSALGIA, SUDECK’s bone atrophy SUDECK’s ATROPHY, traumatic conductive neuralgia TRAMATIC SPEADING NEURALGIA, and sympathetic maintenance pain are commonly used clinically SMP to describe common neurogenic pain syndromes or neuropathic pain syndromes.
RSD,SMP,CRPS,CAUSALGIA
RSD —- Reflex sympathetic dystrophy. The term refers to a pathogenic pain syndrome that includes both symptomatic and dystrophic changes due to pathological abnormalities in the activity of the sympathetic nervous system.
SMP —- Sympathetic maintenance pain. It is often described as a pain syndrome in which the application of sympathetic treatment techniques results in pain relief. The condition often has no clinical positive signs and has significant symptoms with “no clear clinical diagnosis”.
CRPS —- Complex regional pain syndrome. The term complex refers to the variety of clinical phenomena and uncharacterized diagnostic pain in each type of disease. The term regional is due to the typical regional distribution of signs and symptoms of such disorders. RSD and Causalgia (burning pain) have now been classified as CRPS-I and CRPS-II.
Complex regional pain syndrome (CRPS-I)
CRPS-I ( reflex sympathetic dystrophy RSD)
It can be caused by trauma to the limbs, visceral diseases (diseases affecting internal organs) and damage to the central nervous system. Symptoms mainly include.
1, pain, burning sensation.
2. alteration of skin temperature in the affected area.
3. skin and nail changes and slowed hair growth.
4, edema of the limbs resulting in reduced joint mobility.
RSD predisposing factors.
Trauma: sprains, fractures, crush injuries, and cuts, etc., common in the distal limb, and the severity of the injury is not related to the symptoms of the disease.
Medical injury: nerve injury caused by lower limb surgery, tight limb wrapping, surgical scars, injections or over-force massage.
Diseases: myocardial infarction, infection, vascular diseases, neurogenic diseases and injuries including spinal cord and peripheral nerves or plexus, tumors, musculoskeletal system diseases.
Reflex sympathetic dystrophy
? Treatment.
1, drugs: tricyclic antidepressants, antitussives, anti-inflammatory drugs, hormones and sympathetic blocking drugs.
2, repetitive sympathetic blockade.
3, biofeedback and muscle relaxation training.
4, physiotherapy to promote joint movement and muscle strength.
5.Psychotherapy.
6.Spinal cord electrical stimulation can be used for recalcitrant cases.
Indeterminate presentation
Indeterminate presentation is a kind of clinical lesion with generalized fatigue, fatigue, headache, insomnia, abnormal gastrointestinal function and other somatic symptoms that are not fixed, with multiple complaints, and the physical signs do not match with the complaints.
I. Classification of indefinite statements
? Neurological type: predominantly psychological symptoms.
? Psychosomatic type: predominantly psychological and vegetative dysfunctions.
? Primary vegetative dysfunction: no psychological factors.
II. Diagnosis of indeterminate statements
? Only self-conscious symptoms without positive signs.
? chills.
? positive Shellong rise test.
Postherpetic neuralgia
? medications: tricyclic antidepressants combined with PHENOTHIAZINES and antitussives.
? nerve blocks or cryotherapy of the involved nerve to prolong the duration of pain relief.
? sympathetic nerve blocks: the disease is usually combined with abnormal sympathetic nerve function, and early use may reduce the chance of postherpetic neuralgia and may prolong the duration of pain relief.
? Transcutaneous electrical stimulation: helps to improve the pain state.
? Psychological treatment: Psycho-psychological aspects are important as mental depression is present in approximately more than 50% of patients. Biofeedback and muscle relaxation training can also significantly help these patients to overcome their pain.
? Spinal cord electrical stimulation: used in intractable cases.