Many solicitors and barristers have only become aware of the significance of pain disorders in personal injury actions relatively recently. This is a complex area. It is preferable that a correct diagnosis is made at as early stage as possible if treatment is to be successful, though I have been involved with cases where a diagnosis has been made a number of years following injury and a successful outcome has been achieved. There seems to be a view in the legal world that that once diagnosed with a pain disorder it is unlikely that treatment will significantly improve the condition. However, that is not my experience and defendant lawyers and insurers should be conscious of the fact that the value of a claim can dramatically increase if a pain disorder is not identified and treated early on, because very often the condition results in a reduced earning capacity or inability to work at all.
What is pain?
Pain is defined as an unpleasant sensory and emotional experience, which we primarily associate with tissue damage or describe in terms of tissue damage, or both, according to the International Association for the Study of Pain. A more useful definition is to say that pain is whatever the client says it is.
Pain comes in two time courses: acute pain and chronic pain. By definition, acute pain lasts for less than three months and includes post-operative pain, pain following road traffic accidents and, most acutely, painful medical and surgical conditions, such as appendicitis, peritonitis and other acute inflammatory conditions. Chronic pain, by definition, is defined as lasting for three months or more and includes common complaints such as neck pain, lower back pain, joint pain etc.
Types of pain
Pain can be divided into two major types. Nociceptive, or normal pain, is where the pain signalling pathways are all in tact and this is most commonly found with musculoskeletal pain, eg lower back pain and neck pain.
Neuropathic pain, on the other hand, is a form of pain where there is damage and/or dysfunction to any element of the nervous system. Patients usually describe very florid symptoms with this. They will describe their pain as sharp, stabling, like electric shocks, like hot, stabbing pokers or razor blades. They also suffer with a lot of burning pain.
In addition to the pain, patients will experience sensory dysfunction – light touches and pinprick sensations will be felt as exaggerated. This can often lead to problems, for instance in showering and wearing clothing where the affected area can be acutely painful. Along with pain, patients often have associated disability with their pain. For instance, where a limb movement of the affected area causes pain they will start to disuse the area, leading to neglect, muscle wasting and in extreme cases, fibrosis and contractures. This leads to further disability.
Examples of pain
Nociceptive pain includes:
- Whiplash injury;
- Lower back pain;
- Shoulder pain; and
Neuropathic pain includes:
- Complex regional pain syndrome (CRPS)
- Industrial accidents;
- Post-traumatic neuropathic pain;
- Paraplegia; and
The pain signalling pathway is an immensely complex neurophysiological system.
In essence, there are pain receptors that are receptive to motor, thermal and chemical stimuli found throughout the body, both peripherally and in the viscera. These are connected by mostly A delta and C fibres back to the spinal cord.
In the spinal cord, pain transmission can be modulated, either amplified or depressed, by a number of local ascending and descending inhibitory and excitatory neural circuits. After this modulation, the pain signal is transmitted up through the spinal cord via five different tracts, the most common of which is the spinothalamic tract.
These pain fibres then end up in about five different areas in the brain, as there is no central pain processing area, and these discrete areas in the brain translate into the different aspects of pain, including location, intensity, type, character, emotional response and other valuable information.
Telelogically, pain has been developed in organisms to keep the organism out of harm’s way. For instance, if a limb is injured, there is an initial reflex action to remove the limb from danger. If it is injured, the pain will signal to the organism not to use that area until it has healed.
Prevalence of pain
To give an example, in a busy hospital such as St Mary’s Hospital in London, over 13,000 operations are performed per year. A significant number of these will require analgesic medication in the post-operative period.
The figures stated that one in seven of the UK population lives with chronic pain. This equates to approximately 7-14% of the UK population and these findings are similar in the western world.
The challenge of long-term pain
Clinicians look at pain with a bio-psychosocial model. Biologically, clients suffer with and disability. Psychologically, they have higher levels of anxiety and depression than others. Socially, pain can lead to relationship difficulties, difficulties in the workplace and can often lead to patients struggling to cope with family and working life, and physical deterioration. In severe cases, they may end up going onto benefits.
Psychical and alternative treatments
Physical treatments for pain include heat packs, cold packs, TENS machines, hydrotherapy, support, ultrasound and infrared. Manipulation techniques include physiotherapy, chiropractic, osteopathy and deep tissue massage. Alternative treatments include acupuncture.
For pain treatment we consult the bridged World Health Organisation analgesic ladder. Step 1 for mild pain includes paracetamol, non-steriodals and COX-2 inhibitors. Step 2 is Step 1 plus the addition of weak opioids including codeine, dihydrocodeine and tramadol. Step 3 includes step 1 and the addition of strong opioids including morphine, oxycodone, and buprenorphine etc. In the past few years, there has been an increasing use of opiates, that is morphine-like drugs, in the treatment of chronic non-malignant pain. This has in some way been down to some of the more deleterious and irreversible adverse effects of the non-steriodal and cyclooxygenase inhibitor medications, which in long-term use have been associated with renal impairment and an increase in strokes and heart attacks.
Medication for neuropathic (nerve) pain
These medications are drugs that are generally used for other purposes but that have been found to be useful in neuropathic pain. Examples include:
- Opioid medication;
- Local anaesthetics; and
Other agents include NMDA, antagonists, sympatholytics, GABAergics and capsaicin.
The pharmaceutical industry has a significant interest in medications for neuropathic pain, as it is seen as a significant market. Agents include ziconotide preparation from sea-snail toxin, epibatidine preparation from the Ecudorian poison dart frog and other preparations in the pipeline.
Psychologically based therapy
It is often necessary to use psychologically based therapies, including cognitive behavioural therapy, conditionings, psychoanalysis, relaxation and biofeedback. Only very rarely it is necessary to involve psychiatric input, in particular where clients have suicidal ideation or there is an underlying significant psychiatric problem, such as sever depression or schizophrenia.
Pain management programmes seek to teach patients, usually in groups on an inpatient out outpatient basis, a variety of self-help techniques to help them manage their pain more effectively. These sessions are done with a multidisciplinary team, usually comprised of a doctor, specialist pain nurse, physiotherapist, occupational therapist, pharmacist and other staff.
Techniques taught include management of medication, coping strategies and contingency plans, pacing of activity, education of patients regarding their pain, teaching patients goal-setting and trying to break certain negative pain behaviours.
Minimally invasive pain management
There are a number of different procedures that are used either with or without x-ray guidance.
Minimally invasive pain management procedure for musculoskeletal pain include:
- Facet joint injections;
- Nerve root injections;
- Suprascapular nerve blocks;
- Obturator nerve blocks; and
- Intra-articular nerve blocks.
Minimally invasive pain management for neuropathic pain includes:
- Intravenous guanethidine blocks (IVG);
- Lumbar sympathectomy;
- Stellate ganglion nerve blocks;
- Ganglion of impar block; and
- Occipital nerve block.
Most of these procedures are performed under x-ray guidance and can usually be done either with the patient awake or under local anaesthesia or with the addition of a small amount of sedation. Most of the procedures involve the injection of mixtures of local anaesthetic and cortisone.
Another technique, which has been around since the 1950s, is the use of radiofrequency technology. This can be used as a destructive mode (radio frequency denervation) for, for instance, lumbar facet joint pain to destroy the local pain mediating nerves, or can be used in a non-destructive mode (pulsed radiofrequency) for areas of neuropathic pain. In the destructive mode, nerves are actually destroyed with the application of an electric field. In the non-destructive mode, pulses of electrical field are passed through local nerves and there is excellent basic sciences evidence of the beneficial effects of pulsed electrical fields on nerve membranes including stabilising them, reducing their activation threshold and reducing the amount of spontaneous activity in them.
Advanced pain-management techniques
There are a number of other techniques such as kyphoplasty and vertebroplasty. These are percutaneous techniques for patients who have vertebral crush fractures either secondary to malignancy, osteoporosis or trauma in which bone cement is put under x-ray control into the lumbar vertebral bodies.
Spinal cord stimulation is an advanced technique for patients who have pain that has been refractory to medication and minimally invasive pain-management procedures, eg patients who have CRPS that is refractory. In this, electrodes are placed adjacent to the affected target area of the spinal cord. The electrode leads are buried under the skin and tunnelled to a pocket in the anterior abdominal wall where there is a battery pack and small computer. The electrode array can then be controlled in terms of frequency, voltage, bursts of activity and electrode array pattern.
Yet other advanced techniques include the role of intrathecal pumps. These again are implanted devices where a small cannula indwells in the intrathecal space and a reservoir containing opiates, balclofen or other substances are slowly delivered into the central nervous system via the cerebral spinal fluid.
Medical-legal cases reports
The following anonymised cases are examples of personal injury claims, which I have dealt with in practice, to illustrate the effectiveness of appropriate treatment.
A 54 year old woman was involved in a road traffic accident at 60 mph. She was hit from the side and went into the central reservation, turning the car over. The driver was killed outright and the passenger was rendered paraplegic. The index client was a passenger in the back of the vehicle.
This lady was seen three years after the initial road traffic accident. She had a whiplash injury, lower back pain, shoulder pain, post-traumatic stress disorder (PTSD) and severe sleep disturbance.
She had a course of medication including antineuropathic medication and high dose anti-inflammatory medication. She was seen by a pain psychologist and had sessions of counselling for her PTSD. She went on to have minimally invasive pain-management procedures including cervical and lumbar facet joint injections. This was followed by physiotherapy-based rehabilitation.
After three months of intensive treatment, there was a reduction in her pain scores, a reduction in depression scores, improved sleep. Increased range of movement of her cervical and lumbar spine and she was ultimately discharged.
A 38 year old women had a fill in the workplace down two steps and fractured her ankle. She went on to develop CRPS, a form of neuropthaic pain.
Symptom-wise, she had hypersensitivity of the foot, constant burning pain with sharp, acute electrical exacerbations. She was unable to weight-bear, unable to wear shoes, suffered depression and ultimately lost her job.
She was seen approximately 18 months after her index accident. she was tried on a wide number of different antineuropathic medications but unfortunately suffered with adverse effects from these. She went on to have a lumbar sympathectomy, IVGs and intravenous lignocaine infusions. Unfortunately, although these were initially beneficial, their effects only lasted a few weeks. Eventually, after approximately four months she was referred for implantation of a spinal cord stimulator. Two years later, this lady still has her spinal cord stimulator in situ.
There were objective and subjective reductions in neuropathic pain. She has now returned to the workplace – a significant milestone in the rehabilitation of patients suffering from pain disorders.
In summary, pain is very common. It has a time course of acute and chronic pain. Chronic pain affects up to one in seven of the UK population. There are two major types of pain: nociceptive and neuropathic pain. Overall, it has a massive socio-economic impact. There are multiple treatments including medication, minimally invasive pain-management procedures, physiotherapy-based rehabilitation and any psychological input that may be required. There are also a significantly large number of medico-legal claims in the system in which clients have pain as a significant factor in their case.
This article was written by Dr Christopher Jenner in the June 2008 addition of the Personal Injury Law Journal