The Myth of the
'Pinched Nerve'
An interesting article in the science section of 'Sueddeutsche Zeitung'
describes a new shift in the understanding of musculoskeletal pain. It is based
on the recent congress on pain symptoms (Deutsche Schmerzkongress) in
Duesseldorf and the article contains frequent quotations from the president of
that congress, Dr .med. Kay Brune from Erlangen.
Originaltext des Artikels auf
Deutsch
"The idea that pain in the motor apparatus is
dominantly a consequence of 'pinched nerves' and could be ultimately freed by
removing the bony or muscular obstructions, is now considered as old fashioned
and no longer valid.. Neurophysiologists now assume instead that successful
joint manipulation - similar to other physical treatments - reduces the pain by
stimulating the nerve fibers which lower the excitability of the cell in the
central nervous system."
.
Whereas in the past research and treatment of back pain had been
predominantly oriented around biomechanical explanations ("pinched
nerve",) contemporary models now seem to give much more emphasis on
neurophysiological ("pain memory") aspects of back pain.
According
to data published by the renown Emnid Institute, two thirds of all citizens
complain of recurring pain in their locomotor system, 61 percent are impaired
in their daily activities by it, and every third day of work disability is
caused by back pain. Yet 85% of the chronic back patients are not treated
sufficiently.
According
to Kay Brune "the surest method against backache is no bed rest,
no X-ray and no surgery. In the case of acute backache it is rather
important to continue with the normal active life. Operations rarely lead
to continuous improvement - on the contrary" says Brune. Because quiet
periods contributed to make the pains become chronic. The most effective therapy
against backache is therefore early mobilization. Once a person gets into the
vicious circle of pain and rest it is usually hard to move out of it
without medical help. If you reduce your physical activity too much the
stability of your spinal column will get worse, which leads together with a bad
posture to intensified pain.
But
even without any wrong behavior acute troubles may become chronic. Every
painful stimulus triggers electric impulses in the peripheral end of thin nerve
fibers, which run to a coordinating point in the spinal cord. As a reaction to
these impulses, carriers (neurotransmitters) are set free which as chemical
'messenger' give information to the central nervous system.
As
nerve cells are able to learn, their way of function changes if they are
stimulated either for a long time or repeatedly in the same way. According to
Walter Zieglgänsberger of the Max-Planck-Institute for Psychiatry in Munich the
intensity of the pain then increases, since the same stimulus then leads to
a higher number of electric discharges in the spinal cord (which had
been reported before in SZ 26.3.98). If the excitability of the nerve cells
increases then also the 'receptive areal' increases which is the area
which is sensitive to pain. Then suddenly not only the shoulder hurts but the
whole arm. Sometimes these nerve cells produce pain impulses even though
there is no real stimulus in the periphery. Similar neural mechanisms have
recently been accepted as a basis of the 'phantom limb' pain which amputees frequently
feel and which had not been understood before.
Not
all persons develop a chronic illness as a result of acute pain experiences.
These persons are protected by systems within their own body which dampen the
increased excitability of the cells in the spinal cord. In the neighborhood of
these excitatory fields there are also areas which hinder the activity of nerve
discharges as soon as they are stimulated. And how excitable a cell is depends
also on hormonal and immunological factors.
'These
neurophysiological findings are very important for the therapy' says Hermann
Locher of the 'International Association for Orthopedic Pain Research' (IGOST).
The idea that pain in the motor apparatus is dominantly a consequence of
'pinched nerves' and could be ultimately freed by removing the bony or muscular
obstructions, is now considered as old fashioned and no longer valid.. Neurophysiologists
now assume instead that successful joint manipulation - similar to other
physical treatments - reduces the pain by stimulating the nerve fibers which
lower the excitability of the cell in the central nervous system. Therefore
the common assumption of most physicians that one should not manipulate more
than three times repeatedly isn't valid any more.
On
the contrary: In order to achieve a permanent reduction of the increased
excitability, the pain causing stimulus must be interrupted until the nerve
cells have 'forgotten' it. In therapy one should not wait until the pain
returns, but one has to intervene before that. 'Therefore today we start to
treat more individually than in former times, specially in regards to the
frequency of manipulation' reports orthopedic doctor Hermann Locher. For
chronic pain patients the 'serial' therapy has been established in which some
patients are treated even daily for a while. In his opinion acupuncture can be
used in the same way. Furthermore this new neurophysiological modell
presents an understanding on the molecular and micro-anatomical aspects about
how this method could function.
For
Zieglgänsberger acupuncture and electrostimulation are methods which follow
the same principles as manual medicine or massage. In his opinion the new
neurophysiological concept explains also the influence of psychological and
social factors on chronification of pain. Already in the beginning of the
90s US-scientists published a study which showed that for the prognosis of the
progression of backpain symptoms of a given patient the situation at work is
more important than the severity of the acute pain.
The article - written by Marcela Ullman - appeared on
Nov 17. 1998 in the science section of the 'Suedddeutsche Zeitung'. Translation
and summary into English by Karin Paleczek.