Pain management (also called pain medicine; algiatry) is that branch of medicine employing an interdisciplinary approach to easing the suffering and improving the quality of life of those living with pain. The typical pain management team includes medical practitioners, clinical psychologists, physiotherapists, occupational therapists, and nurse practitioners. Pain sometimes resolves promptly once the underlying trauma or pathology has healed, and is treated by one practitioner, with drugs such as analgesics and (occasionally) anxiolytics. Effective management of long term pain, however, frequently requires the coordinated efforts of the management team.
Pain management practitioners come from all fields of medicine. Most often, pain fellowship trained physicians are anaesthesiologists, neurologists, physiatrists or psychiatrists. Palliative Care doctors are also specialists in pain management. Some practitioners have not been fellowship trained and have opted for certification by the American Board of Pain Medicine which is not recognized by the American Board of Medical Specialties and does not indicate fellowship training. However, the American Board of Anaesthesiology does have a sub specialty in Pain Management which is recognized by the American Board of Medical Specialties and does indicate fellowship training. Some practitioners focus more on the pharmacologic management of the patient, while others are very proficient at the interventional management of pain. Interventional procedures – typically used for chronic back pain – include: epidural steroid injections, facet joint injections, neurolytic blocks, Spinal Cord Stimulators and intrathecal drug delivery system implants, etc. Over the last several years the number of interventional procedures done for pain has grown to a very large number.
As well as medical practitioners, the area of pain management may often benefit from the input of Physiotherapists, Chiropractors, Clinical psychologists and Occupational therapists, amongst others. Together the multidisciplinary team can help create a package of care suitable to the patient. One of the pain management modalities are trigger point injections and nerve blocks utilizing long acting anaesthetics and small doses of steroids.
Because of the fast growth in the field of Pain Medicine many practitioners have entered the field, with many of these practitioners being not board certified or being certified by unrecognized boards.
Medicine treats injury and pathology to support and speed healing; and treats distressing symptoms such as pain to relieve suffering during treatment and healing. When a painful injury or pathology is resistant to treatment and persists, when pain persists after the injury or pathology has healed, and when medical science cannot identify the cause of pain, the task of medicine is to relieve suffering. Treatment approaches to long term pain include pharmacologic measures, such as analgesics, tricyclic antidepressants and anticonvulsants, interventional procedures, physical therapy, physical exercise, application of ice and/or heat, and psychological measures, such as biofeedback and cognitive behavioral therapy.
The World Health Organization (WHO) recommends a pain ladder for managing analgesia which was first described for use in cancer pain, but can be used by medical professionals as a general principle when dealing with analgesia for any type of pain. In the treatment of chronic pain, whether due to malignant or benign processes, the three-step WHO Analgesic Ladder provides guidelines for selecting the kind and stepping up the amount of analgesia. The exact medications recommended will vary with the country and the individual treatment centre, but the following gives an example of the WHO approach to treating chronic pain with medications. If, at any point, treatment fails to provide adequate pain relief, then the doctor and patient move onto the next step.
Mild to moderate pain
Moderate to severe pain
Morphine is the gold standard of choice, followed by Oxycodone, Hydromorphone, Oxymorphone and Fentanyl in the form of a transdermal patch designed for chronic pain management. Diamorphine, Methadone and Buprenorphine are used less frequently.Pethidine is not recommended for chronic pain management due to its low potency, short duration of action, and toxicity associated with repeated use. Amitriptyline is prescribed for chronic muscular pain in the arms,lower back,legs and neck. While opiates are often used in the management of chronic pain, high doses are associated with an increased risk of opioid overdose.
Opioid medications can provide a short, intermediate or long acting analgesia depending upon the specific properties of the medication and whether it is formulated as an extended release drug. Opioid medications may be administered orally, by injection, via nasal mucosa or oral mucosa, rectal, transdermal, intravenously, epidurally and intrathecally. In chronic pain conditions that are opioid responsive a combination of a long acting or extended release medication is often prescribed in conjunction with a shorter acting medication for breakthrough pain (exacerbations).
Although opioids are strong analgesics, they do not provide complete analgesia regardless of whether the pain is acute or chronic in origin. Opioids are efficacious analgesics in chronic malignant pain and modestly effective in non malignant pain management. However, there are associated adverse effects, especially during the commencement or change in dose. When opioids are used for prolonged periods drug tolerance, chemical dependency and, rarely, diversion and addiction may occur.
Non-steroidal anti-inflammatory drugs
The other major group of analgesics are Non-steroidal anti-inflammatory drugs (NSAID). This class of medications does not include acetaminophen, which has minimal anti-inflammatory properties. However, acetaminophen may be administered as a single medication or in combination with other analgesics (both NSAIDs and opioids). The alternatively prescribed NSAIDs such as ketoprofen and piroxicam, have limited benefit in chronic pain disorders and with long term use is associated with significant adverse effects. The use of selective NSAIDs designated as selective COX-2 inhibitors have significant cardiovascular and cerebrovascular risks which have limited their utilization.
Antidepressants and antiepileptic drugs
Some antidepressant and antiepileptic drugs are used in chronic pain management and act primarily within the pain pathways of the central nervous system, though peripheral mechanisms have been attributed as well. These mechanisms vary and in general are more effective in neuropathic pain disorders as well as complex regional pain syndrome. Drugs such as Gabapentin have been widely prescribed for the off-label use of pain control. The list of side effects for these classes of drugs are typically much longer than opiate or NSAID treatments for chronic pain, and many antiepileptics cannot be suddenly stopped without the risk of seizure.
Other Adjuvant & Atypical Analgesic Agents
Other drugs are often used to help analgesics combat various types of pain and parts of the overall pain experience. In addition to gabapentin, the vast majority of which is used off-label for this purpose, orphenadrine, cyclobenzaprine, trazadone and other drugs with anticholinergic properties are useful in conjunction with opioids for neuropathic pain. Orphenadrine and cyclobenzaprine are also muscle relaxants and are therefore particularly useful in painful musculoskeletal conditions. Clonidine has found use as an analgesic for this same purpose and all of the mentioned drugs potentiate the effects of opioids overall.
Pulsed radiofrequency, neuromodulation, direct introduction of medication and nerve ablation may be used to target either the tissue structures and organ/systems responsible for persistent nociception or the nociceptors from the structures implicated as the source of chronic pain.
An intrathecal pump used to deliver very small quantities of medications directly to the spinal fluid. This is similar to epidural infusions used in labour and postoperatively. The major differences are that it is much more common for the drug to be delivered into the spinal fluid (intrathecal) rather than epidurally, and the pump can be fully implanted under the skin. This approach allows the drug to be delivered directly to the site of action, ie the spinal cord, and so allows a higher dose to be given with less systemic side effects.
A spinal cord stimulator is an implantable medical device that creates electric impulses and applies them near the dorsal surface of the spinal cord provides a paresthesia (“tingling”) sensation that alters the perception of pain by the patient.
Physical medicine and rehabilitation (Physiatry) employs diverse physical techniques such as thermal agents and electrotherapy, as well as therapeutic exercise and behavioral therapy, alone or in tandem with interventional techniques and conventional pharmacotherapy to treat pain, usually as part of an interdisciplinary or multidisciplinary program
Transcutaneous electrical nerve stimulation (TENS or TeNS) is the application of electrical current through the skin for pain control. The unit is usually connected to the skin using two or more electrodes. A typical battery-operated TENS unit is able to modulate pulse width, frequency and intensity. Studies comparing TENS with placebo (sham TENS) in the treatment of chronic low back pain provide conflicting results, with 2 Class I studies and one Class II study showing no benefit, and 2 Class II studies showing benefit. Class I studies are stronger evidence, so it appears that TENS is ineffective for the treatment of low back pain. Two Class II studies demonstrate probable effectiveness in the treatment of painful diabetic neuropathy. More high quality research into the effectiveness of TENS is needed.
Main article: Acupuncture
Acupuncture involves the insertion and manipulation of needles into specific points on the body to relieve pain or for therapeutic purposes. In 2003, the World Health Organization published an article synthesizing the scientific research (controlled trials) of the time, and concluded acupuncture is helpful for the treatment of pain in some cases of acute epigastralgia, facial pain, headache, knee pain, low back pain, neck pain, pain in dentistry, postoperative pain, renal colic, and sciatica. The authors also concluded acupuncture has demonstrated effectiveness in other conditions for which further proof is needed. This review has been criticized for giving too much weight to low-quality clinical trials, and including a large number of trials originating in China. The latter issue is considered problematic because trials originating in the West include a mixture of positive, negative and neutral results while all trials in China are positive (attributed to publication bias rather than fraud).An analysis of the 13 highest quality studies of pain treatment with acupuncture, published in January 2009 in the British Medical Journal, concluded there was little difference in the effect of real, sham and no acupuncture. There is general agreement that acupuncture is safe when administered by well-trained practitioners using sterile needles, and that further research is appropriate.
Cognitive and Behavioural therapy
Main article: Cognitive behavioral therapy
Mindfulness-based cognitive therapy, the use of stress reduction and relaxation, has been found to reduce chronic pain in some patients. Applied behaviour analysis views chronic pain as a consequence of both respondent and operant conditioning, where a patient learns to display pain behaviour in the presence of specific environmental antecedents and consequences. The model was first proposed by Fordyce in 1976. Though cognitive-behavioural intervention can be an effective and economical means of treating chronic pain, the effects are rather modest and a substantial portion of patients gain no benefit.
Main article: Biofeedback
Biofeedback based on behavioural principles has shown some success for chronic pain, demonstrating greater improvement in one study than peers undergoing cognitive-behavioural therapy and conservative medical treatment, though a different study showed improvements over wait-list controls but no difference between biofeedback and cognitive-behavioural therapy
A 2007 review of 13 studies found evidence for the efficacy of hypnosis in the reduction of pain in some conditions, though the number of patients enrolled in the studies was small, bringing up issues of power to detect group differences, and most lacked credible controls for placebo and/or expectation. The authors concluded that “although the findings provide support for the general applicability of hypnosis in the treatment of chronic pain, considerably more research will be needed to fully determine the effects of hypnosis for different chronic-pain conditions.”
Clinical description of pain
For the purposes of pain management and research, the International Association for the Study of Pain recommends describing pain according to
- Its anatomical location (neck, lower back, etc.)
- The body system involved (gastrointestinal, nervous, etc.)
- Temporal characteristics (intermittent, constant, etc.)
- Intensity and time since onset
This classification system has been criticized by Wolfe and others as inadequate for guiding research and treatment. They propose the development of an additional category based, not on symptoms or underlying conditions, but on the type of neural activity generating the pain.
The Multidimensional Pain Inventory (MPI) consists of a set of empirically derived scales designed to assess chronic pain patients’ psychosocial state. Turk and Rudy found three types of chronic pain patient: “(a) dysfunctional, patients who perceived the severity of their pain to be high, reported that pain interfered with much of their lives, reported a higher degree of psychological distress caused by pain, and reported low levels of activity; (b) interpersonally distressed, patients with a common perception that significant others were not very supportive of their pain problems; and (c) adaptive copers, patients who reported high levels of social support, relatively low levels of pain and perceived interference, and relatively high levels of activity Turk and Okifuji recommend combining MPI characterization of the patient with that of the IASP multiaxial system to derive the most useful case description.