Central Pain in Brachial Plexus Injuries

In 1911 a patient described the pain from a serious brachial plexus injury as follows; 'The pain is continuous, it does not stop a minute either day or night. It is either burning or compressing...in addition, there is, every few minutes, a jerking sensation similar to that obtained by touching...a Leydon Jar. It is like a zig zag in the sky made by a stoke of lightning. The upper part of the arm is mostly free of pain; the lower part from a little above the elbow to the tips of the fingers, never.'

A Leydon Jar is a primitive type of capacitator.   "1745 C.E. - E.G. von Kleist (German) and shortly thereafter, Pieter van Musschenbroek, (Dutch) invent "the Leydon Jar," which collects and stores a concentrated electrical charge.

The patient himself was a Doctor so his description was taken seriously. His surgeons, Frazier and Skillern, exposed the plexus and found C6, C7 and C8 had been torn completely from the spinal cord (ref 1.)
This is typical of the pain of avulsions in the brachial plexus.
There are often two parts to the pain, one constant, the other intermittent and it is felt most in the hand and forearm. Research has shown that the severity of the pain is related to the extent of lesion. 

 

There have been many studies carried out regarding the pain, because after the loss of sensory and motor function of the arm, it is the single biggest problem in traumatic brachial plexus injuries. As patients accept the loss of function in the affected arm, they often find it much harder to accept the pain, which in some cases continues for years. Bonney followed 25 patients for at least 2 years, pain was worst in those with no recovery (ref 2.) Seddon referred to Yeoman's studies, who found that severe pain persisted in 32 out of 46 cases of complete paralysis, and in 22 of 44 who had gained spontaneous elbow flexion (ref 3.) Wynn Parry has made detailed studies which describe the characteristics, the time of onset and the relation between the extent of injury and such factors as cold, illness etc. to the level of pain. In 1980 he reported on 122 cases of avulsion of at least one spinal nerve. Of these, 112 had severe pain, which was exacerbated by cold, worry or illness. He found that distraction by work, play or conversation considerably improved the pain in most cases. Pain remained severe at 3 years or more post injury in 48 cases. He later reported on 404 patients with avulsions over periods of 3-35 years. In just over half of these cases, the pain subsided within 3 years, in a third the pain lasted longer but was accepted and did not interfere with daily life. In 20%, however, severe pain persisted for many years and continued to seriously affect the lives of the patients. In only 1% was there no pain at all. T1 was avulsed in all patients with severe pain persisting for more than 3 years, the total plexus was also damaged in almost half of these. (ref 4.) Most patients do report either lessening of the pain, or tolerance to it which enables them to continue a normal life long term.
 


Current treatments

Distraction
 
Many patients report significant easing of the pain when they are engaged in activities, whether these are work, exercise or just conversation. It isn't that the pain is 'in the mind' i.e. not real, more that the occupation of the individual seems to distract the brain from registering the pain. In time most patients learn to do this for themselves automatically, severe pain may still be present some time after injury but the sufferer learns to work round it. Getting to this stage is a very important part of recovering from the injury. Some clinics will help patients learn techniques that will enable them to live with the pain.

Distraction is probably the technique used by most people, by simply getting on with their daily lives. If it isn't working, or pain prevents the normal activities that provide your distraction, further help should be sought. If you feel you aren't coping where others seem to, it doesn't mean they are 'tougher' than you, it means you have a pain problem that may require several different approaches until you find the right one.  

Transcutaneous Stimulation

In this method the skin is stimulated by a device which emits electrical pulses. The theory is that these pulses stimulate pain inhibiting impulses to be transmitted by the brain in response. To be effective, the patient must be educated in its use, and helped by the physician to find which of various possible positions of the stimulator, together with varying frequencies, duration and amplitude are most effective in each case. It is of little use to just obtain a stimulator and experiment yourself. It helps if a pain diary is kept before the stimulator is tried, in order that its effectiveness can be measured. It needs to be tried for many hours during each day and for at least 2 weeks to gauge its effectiveness. During this time the diary should be updated. Many patients do report good results, including one case at the Royal National Orthopaedic Hospital, Stanmore, where a patient who had been in pain for 50 years obtained significant relief in 2 days. Sindou and Keravel report that this method is unlikely to work in cases of complete avulsion, where none of the nerve fibres are preserved (ref 5.)

Drugs

Rolfe Birch states in his book 'Surgical Disorders of the Peripheral Nerves' that the usual analgesics are virtually useless in avulsion pain, although he says that very occasionally some relief is obtained from coproxamol or codeine derivatives. Morphine or synthetic opiates too have been found ineffective. Anti epileptic drugs have been found to work in patients in whom shooting pains predominate. Antidepressants also have been found effective by their effect on the serotonin mechanism of the brain. 
Patients who are prescribed these drugs should be aware that they are not being prescribed for depression itself, or because the physician feels the pain is 'all in the mind.' The serotonin mechanism has a controlling influence in the experience of pain as well as affecting the patient's mood. 
Severely depressed or suicidal individuals and those with chronic pain share the same experience. Recurrent stress and intense pain decreases endorphin (natural substances that relieve pain) levels in the brain. This depletion of endorphins is what makes the pain so unbearable, the body's natural pain relieving mechanism is not functioning properly. To restore this mechanism is the function of pain management. 

Cannabis has, anecdotally, been found very successful in many cases, and trials are being undertaken now (2002) in the UK to establish whether it is an effective drug for plexus pain. In many countries, use of this drug for neural pain relief is permitted, but users in other places should be aware that it is illegal and in most cases medical use is not a valid defence against prosecution. In all cases, long term dependence on any drug, legally prescribed or otherwise, is not advisable.
Those individuals who feel their life is seriously affected by pain continuing over a long period should talk to others who have undergone the procedure and weigh up whether it may be the best course of action for them.  


Amputation
 
Amputation has not been found effective in the relief of the central nerve pain in brachial plexus injuries (ref 9.) It can be effective in relieving dragging pain in the shoulder from the weight of the limb, and in flail arms can permit the use of prostheses to regain some functional use of the arm, especially if some upper arm movement has recovered. The factor of Phantom Limb Pain in some cases is a consideration; this is a pain which persists in the lower arm and hand which are no longer there. It is interesting to note that the most severe and persistent cases of pain in brachial plexus injuries seem to occur in those with no sensory input from the hand, which fits in with Ramachandra's theory regarding Phantom Limb pain, which, simply put, means that due to lack of sensory input from the hand, the brain 'remaps' itself so that those areas of the cortex previously used to input from the hand are 'taken over' by adjacent body parts, which continue to stimulate it. The brain therefore feels that the affected limb is functional, and gives signals to move which are not acted upon, leading to an increase in signals and subsequent pain. This theory is not proven at this stage, although it is worth giving the 'mirror box' a try for intractable, crushing pain. Description of this can be found at the following website 
http://www.chiroweb.com/archives/13/10/25.html              Research continues in this area. 


Relief of pain by reinnervation of the limb 

Although the relation between pain and the recovery of function remains obscure, there is increasing evidence that repair by graft or nerve transfer can be useful in the treatment of pain (ref 6.) For this reason, nerve transfers are now sometimes carried out for the specific purpose of pain relief, even some time after injury when it is not realistic to expect any return of function in the arm. Whether this method is successful depends on the type of lesion the patient has, and pain relief may take a very long time to be felt. Use of such operations is increasing for this purpose.
  

Interventions on the spinal cord 

Early examples of spinal cord intervention in the relief of pain were hampered by unreliability of results and the obvious drawbacks of operation in an area where there is potential for serious damage. More work is now being done in this area. Bennett and Tai (ref 7) found lasting and significant pain relief in 5 cases of serious pain in traction injuries of the brachial plexus by the insertion of electrodes into the spinal cord with the patient conscious, the stimulation pattern was then adjusted to the patient's experience. Sindou and Daher developed ablative surgery at the dorsal route entry zone (DREZ). Some problems were experienced in the development of the surgery, side effects such as weakness in the legs was noted in some cases. Further work has been carried out and these operations are far less risky today, although there is a failure rate of around 40% and unquantified evidence of late recurrence of pain, in some cases worse than the pre operative pain. For this reason, DREZ is usually reserved for patients who have very severe pain over a long period, marring their life and who have not responded to a full range of other treatments (ref 8.)


Summary 

It is clear that pain is very significant in brachial plexus injuries; some patients report it as the most significant factor. However, it does improve in the majority of cases, and most patients do continue life after the injury, many with some level of pain still in existence but with the ability to deal with this. It seems that reinnervation, whether spontaneous or operative seems to be directly related to the relief of the pain. In addition to the medical pain relief methods outlined above, patients often try vitamin injections, homeopathic and herbal remedies, hypnotherapy, reiki, chiropractor, massage, thermal stockings worn on the arm and many others. Efficacy has not been proven in many cases, but anecdotally some do seem to provide relief. It is worth talking to other sufferers about how they deal with their own pain. Always try to establish what level of injury another person has before considering embarking on any recommended therapy, the pain from avulsions seems worse and more persistent than other lesions and what works for one may not work for others. In addition, each injury is unique and has its own set of circumstances as regards causation and recovery.

In a small percentage of people pain does continue to affect their lives for many years. They may have continuous pain, or acute bouts lasting long periods, preventing sleep and seriously disrupting life. In such cases, help from a pain clinic should be sought, through a referral from your GP or existing bpi specialist. If necessary, insist-pain is not something anyone should have to deal with every day, it is a serious issue and in the long term can negatively affect a person's whole life and cause serious depression. In many cases, people are advised to see a psychologist as part of the treatment process. This does NOT mean that the doctors are not taking the pain seriously, or think it is imaginary. For reasons stated above, severe intractable pain can have a negative effect on mood and emotional well being, these are issues that need to be addressed as urgently as the pain, the two factors of pain and emotional stability are inextricably related. Stress seems to cause more severe pain, pain causes stress, it is a vicious circle which a psychologist together with the pain clinic may be able to break. Doctors must take the pain as seriously as the functional recovery, long term, unresolved pain is far harder to live with than a non functioning arm. 

Any therapy undertaken should always be discussed with your specialist first. 

QUICK LINKS TO; Ageing and BPI

The following to links will take you to a couple of websites that have more information about Central pain, and how it affects someone with a BPI. 
http://www.centralpain.org/
http://www.painonline.org/intro.htm

REFERENCES

1 Frazier CH Skillern PG Journal of the American Medical Association Vol 57 No 25 December 1911
2 Bonney G Prognosis in traction lesions of the brachial plexus 1959 Journal of Bone and Joint Surgery 41B: 4-35
3 Seddon HJ Surgical Disorders of the Peripheral Nerves 2nd Edition 1975
4 Wynn Parry CB Pain in avulsion lesions of the brachial plexus 1980 Pain 9: 41-53
   Wynn Parry CB Pain in avulsion of the brachial plexus 1989 Neurosurgery 15: 960-965
5 Sindou M Keravel Y Analgesie par le methode d'electrostimulation transcutanee: resultats dans les doleurs neurologiques a propos de 180 cas. 1980 Neurochirugie 25: 153-157
6 Narakas AO The effects on pain of reconstructive neurosurgery in 160 patients with traction/crush injury to the brachial plexus. In: Seigfried J, Zimmerman M (eds) Phantom and stump pain. Springer-Verlag, Berlin, p126. 
7 Bennett MI Tai YMA Cervical dorsal column stimulation relieves pain of brachial plexus avulsion.  1994 Journal of the Royal Society of Medicine: 87 5-7 
8 Sindou M, Daher A Spinal cord ablative procedures for pain. 1988 In: Dubner R, Gebhardt GF, Bond ME (eds) Proceedings of the 5th World Congress in Amsterdam. Elsevier, Amsterdam p 477
Thomas DGT Kitchen ND Long term follow up of dorsal root entry zone lesions in brachial plexus avulsion. 1994 Journal of Neurology, Neurosurgery and Psychiatry 57: 737-738
(9) Jensen TS Rasmussen P Phantom pain and related phenomena after amputation 1989 Wall PD Melzack R Textbook of Pain, 2nd Edition new York, Churchill Livingstone  
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