Ordering nerves

Ordering nerves
A patient with a carpal tunnel syndrome once mentioned that if he put his hand under his chin with his wrist extended, he could move his head and alter an evoked pain in his hand without moving the hand. “It’s really freaky mate” he said. Most clinicians have stories of pain states being produced in odd positions (we’d like to hear about these – more later). Anyway, these clinical findings, along with the fact that a peripheral nerve is anatomically different along its course, became a part of the order of movement principle (OOM) thinking in neurodynamics, something we hold quite dear.

The principle is that for the best clinical exposure of a peripheral nerve problem, take up the part that you think holds the problem first and then progressively add tension to the nerve via the limbs. So for example for a carpal tunnel syndrome, you would start with wrist extension with the rest of the arm in a neutral position and then progressively add elbow extension, shoulder abduction and lateral rotation and finally neck lateral flexion to the other side. It made sense, and it seemed to make it easier to ‘find’ nerve problems.

Twisted clinical behaviours
Using the OOM principle in the clinic could be useful, fun and even give the clinician a workout! So for a proposed nerve entrapment around the buttocks, you would take up hip flexion first, perhaps add a bit of rotation and then progressively add knee extension, ankle dorsiflexion, spinal lateral flexion away from the test side and even neck flexion. For me, the most spectacular uses of the principle were in the foot problems such as ‘plantar fasciitis’ and ‘heel spurs’ – here you would start with the patient’s knee flexed (i.e. nervous system slack) then you dorsiflex and evert the ankle, extend the knee and flex the hip, thus taking the leg into a straight leg raise with the distal end of the sciatic/tibial/plantar nerve complex loaded first. Hidden little foot problems that may well have had their origin in mid tibial nerve discharge would often be exposed and this position could be used to mobilise.

If you listened to the patient about the sequence of movements which aggravated them, you could replicate the sequence. So during the heel strike phase of running, the ankle is usually in dorsiflexion/eversion followed by knee extension as the phase continues – it fits the position described above.

The order of movement principle could be used for the really sensitive hot nerve problems. Why stir something up by starting at the problem site when you could ‘sneak up’ on the problem by starting movement elsewhere? Hot shoulder with overtones of neuropathic pain? Start movement from the wrist and then the elbow – you may not even have to move the shoulder if these movements reproduce symptoms.

Great theory we thought.

The researchers take a look via the silent mentors
Researchers can sometimes call closing time on clinical behaviours or encourage adaptation of the behaviour. Bob Nee and associates from the Neuropathic Pain Research Group at the University of Queensland did some research on the OOM principle in Taiwan at the Tzu Chi University Medical Simulation Centre using seven fresh frozen cadavers, known as ‘Silent Mentors’. Fresh cadavers for experimental purposes are hard to access and clinicians can be grateful for this research access to this remarkable place.

Nee et al. (2010) demonstrated in the median nerve in the distal forearm, that order of movement changes such as starting with the wrist first or the shoulder first, does not affect the strain or position of the nerve in relation to surrounding structures at the end of the test. Basically on first reading, our much loved OOM principle has been blown out of the water and the first thought from any clinician must be “stuff the researchers“.

Take a closer look at any research
All research needs a careful read. So many people take just one phrase of the findings and leave it at that.

The researchers still recommend that the OOM principle is kept. They suggest that the clinical finding may be due to the starting position simply held for longer than the finishing position. They suggest that the clinical finding may be because certain orders of movement can apply increased levels of strain to a part of the nerve for a longer time period. They also noted that the median nerve glided differently depending on the order of movement. Lastly, likely differences between sequences in ranges of joint motions may still influence nerve biomechanics at the end of a test. In discussions with Bob Nee, the suggestion was made that clinicians can take advantage of these differences in ranges of joint motions. For example, neural tissues can still be tested in highly sensitive or stiff body parts by starting movements away from the painful area. Moving the sensitive or stiff body part last in the neurodynamic test sequence means that it will not have to go through a full range of motion. Bob also said that the study only addressed biomechanical issues and that the different sequences may have different impact on brain circuitry. If the test sequence closely replicates a painful movement it is conceivable that the neural circuitry that represents those body movements in the brain would also be sensitised. It may also be that the movement you apply first, places attention on that part and therefore it is the somatosensory part represented in a pain neurosignature.

The message is: Keep playing with order of movement. Further research will reveal more.

Butler DS 2000 The sensitive nervous system, NOI, Adelaide

Nee RJ et al. (2010) Impact of order of movement on nerve strain and longitudinal excursion. Manual Therapy 15: 376-381.

Your turn
Let us hear your story of pain being provoked in odd positions. A neurodynamics book and DVD to the winner with the most novel position and analysis.

 

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