Flossing nerves

The article, Coppieters MW, Butler DS  2007 Do ‘sliders’ slide and ‘tensioners’ tension? An analysis of neurodynamics techniques and considerations regarding their application. Manual Therapy 13: 213-221, reached top spot for the most downloaded articles in ‘Manual Therapy’ last year. This shows a great interest in clinical applications and research in the area. For these NOI notes we revisit this paper.

The history – “Hey Dave, it’s a slider!”
The idea and practice of sliding and pulling nerves emerged when I was in practice with Helen Slater in the 1990s. We thought, if you pull a nerve at both ends at the same time (e.g. wrist extension and shoulder elevation) then the median nerve would tense and strain and increase intraneural pressure. We called this a ‘tensioner’. However, if you did it the other way (e.g. wrist flexion and shoulder elevation) we thought that the median nerve would tend to slide up and down against neighbouring tissues rather than tensioning.

I recall Helen Slater saying “Hey Dave, It’s a slider!” The name stuck, although we sometimes called it a flossing technique after flossing teeth. In our mechanistic thinking back then, we reasoned that a tensioner would be more appropriate if a nerve was more adhered, perhaps with some intraneural scarring, and we envisaged the technique pumping the intraneural fluids and teasing scar, with  the technique  suitable for a problem chronic carpal tunnel syndrome for example. If a problem was more acute, we thought a sliding technique would be better. It sort of made sense clinically. We had visions of the nerve sliding though blood and exudate and we thought it would probably prevent scarring and might “give the nerve a bit of air and space” The image was one of flossing teeth – “kind of getting the gunk out”.

The research
The idea was only researched in 2007. Research sometimes lags a decade or so behind the clinic! The cadaver study referred to above (see abstract) confirmed the clinical assumptions that sliders create a much larger excursion of the median nerve at the wrist  than tensioners (12.6mm compared to 6.1mm)and the larger excursion is associated with a smaller change in strain (0.8% sliding versus 6.8% tensioning).

Simply said – our techniques of neural mobilizing can be adapted to place differing forces on neural tissues and thus should be adapted to clinician’s best judgements on pathological processes in operation.

These techniques spread quite quickly in the world through the NOI teaching. Regular clinical anecdotes emerged about how good the sliders were and how they resolved a wide range of pain states, especially hamstring problems, low back pain and ‘shin splints’. Check out the nerve movie, courtesy of Michel Coppieters. Note how much the median nerve at the elbow slides in relation to surrounding tissues, when only the wrist is moved.

Some examples of sliders
Some examples are shoulder depression with neck extension (brachial plexus), wrist flexion and elbow extension (median), and a radial nerve test while looking at the hand. You can get quite creative here and there are plenty of examples in the Handbook and DVD.
The slider technique is worth reflecting on. There are likely to be local effects and/or remote effects and it is worth pondering on these.

Slider reflections
Locally, a slider movement could well shift fluids around a nerve and minimizes scarring. The good thing is that you don’t have to move the painful area due to the nerve continuum. Inflammation around nerve is associated with acidic environments which enhance local immune responses and increase intraneural pressures. Movements may well milk the reactive soup out.

The remote effects revolve around the slider techniques being able to provide neurally non- aggressive movements right across the body. With wider body movement, less focusing on a part occurs, allowing distracted and less fearful movement. This probably has a beneficial effect on homoncular reconstruction.
I also like the stories and metaphors that you can construct to facilitate sliding. Peter Edgelow in San Francisco would talk about ‘draining the swamp’ as he got tissues including nerve, going through swollen thoracic outlets. ‘Nerve flossing’ does have some compliance power to it – “have you flossed tonight?”

Your turn
A copy of the Neurodynamics DVD and handbook to the best clinical story about gliding nerves. This could include the most novel slider.

Last month’s notes on Aunty Sue
Thanks to all for your absolutely brilliant stories on catastrophisation and body awareness. Congratulations to Paul for his ‘Love Story’ from Australia who will be sent a graded motor imagery pack. Here’s the first bit of Paul’s story – but read on in the album

Jane was a stroke patient just discharged home after 3 months of rehabilitation. She had regained good mobility but her arm was a disaster. She had a stiff, very painful shoulder and a stiff painful swollen hand. The MCP and PIP joints in the hand were swollen tender and discoloured. Her shoulder stiffness had a solid end feel that suggested capsulitis. This was reinforced by the fact that dystonia was fairly mild. The presentation was typical of a raging shoulder hand syndrome….


Research and evidence is now available online to update your knowledge on graded motor imagery. Download them, print them out and start your own GMI dossier.

Evidence Based document for the graded motor imagery programme [PDF]
Abstracts from recent graded motor imagery research [PDF]
Mirror Box notes for use [PDF]

CRPS-1: Guidelines, practice and evidence [PDF]
(Reproduced with permission from the Australian Physiotherapy Association and Anne Daly)


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