Science Interviews


Sun, 26th Jun 2011

Chronic Pain

Dr Mike Bailey, Pain Management Unit at Ipswich Hospital

Listen Now    Download as mp3 from the show Pushing Back the Pain Barrier

Will - It is estimated that 7 1/2 million people suffer from chronic pain in the UK alone. A survey published in the European Journal of Pain in 2006 on over 46,000 people in 15 countries, found that nearly 1/5th of all adults had suffered pain for 6 months or more. Combined with the fact that it can be very difficult to find effective treatments, chronic pain is a major problem facing healthcare systems, like the British National Health Service.  I travelled to the Pain Management Unit at Ipswich Hospital to speak with Carol Ratcliffe, a retired nurse who has suffered chronic back pain for over 20 years, and with Dr Mike Bailey, the consultant anesthetist and expert in pain management who is now treating Carol, to find out about chronic pain at the front-line of hospital work.

Carol -   I first injured my back when I was working over 20 years ago in 1988.  I was nursing and I transferred a lady back to her wheelchair. As I moved her, following all the rules and regulations, I felt my back suddenly give and I was in pain. I have not worked since.  It has affected me in more ways than even I probably appreciate.  I have problems with sleeping because of the pain.  I cannot walk any distance.  I cannot carry anything.  I cannot lift anything.  I cannot do a supermarket shop.  It has affected me completely and utterly.

Will -   That was Carol Ratcliffe and she’s receiving treatment from Dr. Mike Bailey, a consultant anaesthetist at the Pain Management Unit in Ipswich Hospital.

Mike -   Well Carol’s pain is complex and it’s being treated in a number of ways.  She’s got a range of different pain killers. These include both ordinary pain killers such as combinations of paracetamol and codeine, but also pain killers for nerve pain such as nortriptyline and also something called pregabalin.

Pills_painkillersWill -   And as well as the pain medication that she’s taking as tablets, she’s also having other types of treatments?

Mike -   Yes, Carol has had several spinal operations.  Principally, we do these for patients who’ve had nerve pain, usually in the legs, coming from problems in the lower back.  The surgeons will remove the obstruction to the nerve pathway and hopefully relieve the pain.  Carol has had several of those episodes but sadly, like some people, she has still got nerve pain in her legs from the scarring of the nerves from the original problem.  In a small number of patients in that sad situation with remaining nerve pain after spinal surgery, we can implant special electrodes to stimulate the spinal cord.  What that does is it causes a tingling feeling in the area of the pain and actually relieves the pain by modulating or altering the way in which the nerve messages are sent from the painful legs, up towards the brain.

Will -   How does that actually block the pain?  How does that electrical signal work?

Mike -   What we have been working on for the last 50 years now is something called the ‘Gate Control’ theory of pain.  This was discovered by two scientists in the last century, Patrick Wall, a Neurophysiologist and Anatomist and Ron Melzack who was a Psychologist.  What they noticed is that people could get very severe injuries and feel very little pain.  Conversely, even very minor injuries or apparently healed injuries could still cause a lot of pain. They said that there must be something that influences the pain.  They proposed that there was a so-called gate in the spinal cord in the pathway from the periphery, up towards the brain. We know that in the synapses or junctions between the nerves on that pathway there are chances to change the way in which the pain messages are transmitted.  We call that a gate.  Now we know that certain things can close that gate and some descending nerve messages down the pathway from higher up in the spinal cord are capable of closing the gate in the nerve pathway. That's I think what the electrical stimulation does.  We can use other kinds of electrical stimulation such as a transcutaneous nerve stimulator or TENS machine. That's where we place electrodes on the outer part of the nervous system, on the arm or the leg, but that's not so effective.  And of course, some of the painkillers which we use for nerve pain also act on the spinal pathways. A good example of that is amitriptyline, an old fashioned antidepressant, but it’s also very effective for pain.

Will -   So how effective are all of these treatments at dealing with pain?  Do they actually work?

Mike -   You can never guarantee anything 100%.  If we’re looking at analgesics or painkillers, you can look at numbers needed to treat.  In other words, how many patients would you need to give that medication to, in order to achieve one satisfied patient.  Even for very good painkillers you would need something like 2 to 3 patients in order to get a satisfied customer. Even the more sophisticated treatments like spinal cord stimulation don't have 100% record by any means and there are always side effects for all these treatments.

Will -   So pain is normally thought of as a kind of short time response - someone bangs their foot and they get pain. So why is it that in some cases, as with Carol, she had an injury that hurt her back but then the pain has carried on and it never went away properly.

Mike -   One of the reasons is that nerves do not recover well from injury and they don't heal up like normal tissues. They will often go on being irritable, almost for life, if they've been badly injured.  The other thing is that we don't completely understand all the reasons, but we know that the nervous system sometimes gets a sort of pain memory which can go on causing trouble for years and years.  The nervous system is not a static system like the wiring in our house or even in a computer.  It’s constantly changing and there are changes in the connections in the brain and also lower down in the nervous system to keep old pain circuits going.

Will -   Why do you think pain is being so difficult to find treatments for?

Mike -   The way in which pain is transmitted throughout the body involves many different pathways and many different neurotransmitters, substances that pass as messengers between nerves.  You're having to interfere with that nerve pathway in lots of different ways.  We also know that there are lots of things that can influence pain. For instance if you're stressed you will get an increased pain experience as opposed to someone who is calm.

Will -   That was Dr. Mike Bailey and Carol Ratcliffe at the Pain Management Unit at Ipswich hospital.  Dr. Bailey was also keen to stress that teaching patients psychological coping mechanisms to deal with living with chronic pain is also an important aspect of pain management with the NHS.


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