Pain therapy (synonym: pain medicine) is an important field of medicine or anesthesiology. The term “pain therapy” includes all therapeutic measures that have the effect of reducing pain. Chronic pain patients in particular should be offered an interdisciplinary pain therapy that takes into account not only the physical causes but also psychological and psychosomatic aspects. Pain therapy is made particularly difficult by the fact that pain is subjective and pain intensity can only be defined by the patient alone. The pain therapist is guided solely by the patient’s statements and this often represents a point of conflict. This text serves as an aid to the understanding of pain and has an introductory function with respect to the many procedures of pain therapy, which will be discussed in more detail in subchapters.
Pain – Definition
Pain has been defined by the international association for the study of pain (IASP) as “pain is an unpleasant sensory and emotional experience associated with, or described as, real or potential tissue damage” (IASP 1994). So-called nociception is the neurophysiological perception of pain. Pain receptors are referred to as nociceptors. Depending on the location of these receptors, different pains can be named. There is surface pain (skin) and deep pain (muscle pain, bone pain), which together are called somatic pain. This is contrasted with visceral pain, which refers to pain of the internal organs. Other types of pain or pain designations are as follows:
- Deafferentation pain/phantom limb pain – This pain occurs after the amputation of extremities or, for example, when the brachial plexus (brachial plexus) is torn after a motorcycle accident. One cause of pain is the loss of pain-inhibiting nerve fibers. The “disinhibited” spinal cord neurons send increased pain impulses to the brain, which even interprets the pain as belonging to a limb that is no longer present.
- Nociceptor pain – Direct excitation of nociceptors (pain receptors) during traumatic, inflammatory, or tumorous tissue damage.
- Peripheral neuropathic pain – In general, nerve pathways are stimulated by a pain stimulus and transmit it. This pain stimulus results in peripheral mechanical, chemical, or thermal irritation of the nerve terminal. In neuropathic pain, a pain impulse occurs within the nerve pathway. This results in pain projection, which means that the pain sensation is projected into the area of origin of the nerve (e.g., a skin segment) even though there is no tissue damage there. This pain occurs, for example, when a spinal nerve root is compressed.
- Psychosomatic pain – Psychosomatic pain can be the physical manifestation of a mental condition. The patient somatosizes (“embodies”) a psychological conflict or stress. This pain can play a role in chronic pain in addition to the physical pain origin.
- Reflective pain – This pain occurs, for example, in the context of muscle tension. By the tense muscles, pain receptors are excited, the resulting pain in turn cause the muscle tension, so that a vicious spiral arises. Also tension headache arises in this way.
- Transfer pain – This type of pain occurs when pain that originates visceral (in the internal organs) spreads to a so-called head zone. This phenomenon occurs because afferent (feeding) pain pathways from the skin and internal organs pull together into the central nervous system. If the visceral pain pathway is excited, the brain cannot differentiate where the excitation is coming from and projects the pain to the nerve portion that supplies the skin area, for example. A typical example is the pain in the left arm during a heart attack.
- Central pain – This pain arises either at the tractus spinothalamicus lateralis (pain pathway in the spinal cord) or in the thalamus (part of the diencephalon) as a so-called thalamic pain. The cause can be, for example, an apoplexy (stroke).In addition, damage to the spinal cord, medulla oblongata (medulla oblongata), pons (bridge), midbrain, but also in the cerebral hemispheres can be triggering.
Acute pain vs. chronic pain
Acute pain refers to pain that is foreseeable and slowly decreases as healing progresses. Typical acute pain includes postoperative pain. However, the term “acute” refers to the time period rather than the onset of the pain. This means that acute pain can manifest itself very quickly and suddenly or develop over a longer period of time. The decisive factor is a pain duration of less than six months. Acute pain is to be understood as a warning signal of the body, which plays an important role in the diagnosis of a disease. It has a life-sustaining function by triggering protective reactions, such as pulling the hand away when touching hot objects. In addition, pain-avoiding protective postures promote wound healing of an injured limb. In addition to treatment with analgesics (painkillers), causal therapy of the cause of the pain is the way forward. By definition, chronic pain lasts longer than six months, which means that it outlasts the physiological healing process and loses its warning function. In addition to the physical cause of the pain, psychosocial factors play an increasingly important role here. Psychiatrically, depression resulting from chronic pain often has to be treated. Pain itself becomes a disease in need of treatment. For this reason, multimodal pain therapy is usually the only sensible therapeutic approach.
Starting points of pain therapy
Pain therapy has different starting points, ranging from primary tissue damage to pain perception in the brain, which are exemplified here:
- Tissue damage: Inflammation, edema (swelling), release of inflammatory mediators – cooling, immobilization, anti-inflammatory drugs (anti-inflammatory drugs), analgesics, local anesthesia.
- Peripheral nerve: relay of nociceptor signals – peripheral nerve block, spinal nerve block.
- Spinal cord: transmission and processing of nociceptor signals – systemic or spinal cord administration of opiates, neurosurgical interventions, stimulation procedures.
- Brain: pain perception – general anesthesia, psychological intervention.
Indications (areas of application)
In principle, any pain experienced by a patient as an impairment is in need of treatment. Nevertheless, behind every pain therapy there is an individual decision, which is made by the therapist and the patient together.
The procedures
- Algesimetry (pain measurement)
- Acute pain management
- Exercise therapy
- Chordotomy
- CT-guided periradicular therapy (CT-PRT).
- Electroanesthesia (TENS)
- Cryoanalgesia (icing)
- Local anesthesia
- Drug pain therapy
- Neurodestructive pain therapy
- Patient-controlled analgesia (PCA pump; pain pump).
- Physical pain therapy (physiotherapy)
- Postoperative pain therapy
- Psychological pain therapy
- Regional anesthesia (conduction anesthesia)
- Spinal cord stimulation (SCS; spinal cord stimulation).
- Stellate blockade
- Sympathetic blockade
- Thermotherapy
- Transcutaneous electrical nerve stimulation (TENS)
- Tumor pain therapy
Other pain therapy procedures (complementary pain therapy):
- Acupuncture in pain therapy
- Electrotherapy
- Frequency therapy
- High tone therapy
- Low-level laser therapy
- Neural therapy
- Interference field diagnostics
- Proliferation therapy
- Soft laser therapy
