Structural differentiation

A key element of examination of the physical health and sensitivity of the nervous system (neurodynamics) is structural differentiation (SD). Based on the fact that the nervous system is a continuum, the aim of SD is to provide a clinical diagnosis of whether or not the nervous system is physically compromised in a pain state.

Two examples are below. If spinal flexion hurts in the lumbar spine and neck extension relieves evoked responses, then the inference is that the nervous system is physically compromised, although further clinical data will be need to ascertain where the compromise is. Note that the lumbar and thoracic spines have not been moved only the neck. In the second example, stretch of the upper trapezius muscle could be mechanically loading neural and muscle tissue. If the response is enhanced with the elbow extended, the inference is that neural tissues may be physically compromised.

Fig 10.4 From Butler DS 2000 The Sensitive Nervous System, Noigroup, Adelaide

Michel Coppieters (2006) and colleagues at the University of Queensland carried out a nice piece of cadaveric research on structural differentiation at the ankle. They demonstrated that hip flexion will increase the strain in the tibial nerve at the ankle without altering the strain on the plantar fascia – can you see the diagnostic possibilities here with plantar fasciitis? Clinicians who use the slump test to assist in analysis of plantar fasciitis may have noted that neck movement can alter “plantar fasciitis” symptoms.

It would be nice if it was all that easy! Remember – SD is crude, it calls for skilled manual handling and results need to be taken with other clinical data. And while clear cut responses may occur in pain states involving peripheral neural tissues, it will be a bit more complex and a clinical headache where central sensitisation is a clinical feature. For example, traditional SD teaching is that if ankle dorsiflexion increases lumbar or pelvic responses evoked by a SLR, then “its neural – something is tight or stuck” . However, with central sensitisation, the addition of ankle dorsiflexion could just provide more normal movement input adding to an exiting barrage into the CNS. In future blogs, I will discuss central sensitisation and physical examination of neural tissues.

Talk to me anytime…b1@noigroup.info

Coppieters, M. W., A. M. Alshami, et al. (2006). "Strain and excursion of the sciatic, tibial and plantar nerves during a modified straight leg raise test." J Orthop Res 24: 1883-1889.

Reflections on the Upper Limb Neurodynamic Test (ULNT)

It is worth reflecting on a test now widely used in clinical diagnosis and therapy within physical therapy, yet still with little attention outside the world of physical therapy.

Taken from Figs 12.2D, 12.2E, 12.2F, 12.2G From Butler DS 2000 The Sensitive Nervous System, Noigroup, Adelaide

The Perth based physiotherapist, Bob Elvey, via research and teaching was instrumental in getting the test integrated into manual therapy management in the late 1970s and 80s. Bob always had an emphasis on skilled handling, and perhaps a reason for slow integration outside physiotherapy is that it can be difficult for unpracticed hands. I always liked a description of the test as the “straight leg raise of the arm” (Kenneally et al., 1988) and hoped that this would enhance clinical integration.

In early writings (Butler, 1991), a fairly peripheral and mechanistic approach to the test was taken; the neuroscience revolution in knowledge was yet to unfold. These days we realize that the responses to the test (and also the performance of the test) will be dictated by the underlying pathobiological mechanisms. Simply said, if a person has peripheral neurogenic mechanisms related to scarring, pinching, blood around a nerve, or ” mechanosensitive hot spots” etc in the peripheral nervous system, then the test is very likely to reproduce these problems and identify a neural tissue health issue. However in other pain states where central mechanisms are dominating (eg fibromyalgia), the test needs to be seen as a test of movement rather than a test of damaged tissues.

In summary, the ULNT is a test of all tissues in the upper limb with a preferential focus on the median nerve and its associated plexus and roots. It is also a test of the neural representational stability of the ULNT movement and the meaning of the movement to that person.

For optimal test performance and analysis see “The Sensitive Nervous System” or the neurodynamics DVD. For up to date research on aspects of the test and neurodynamics, Pubmed Coppieters MW.

Butler, D. S. (1991). Mobilisation of the nervous system. Melbourne: Churchill Livingstone.

Kenneally, M., Rubenach, H., & Elvey, R. (1988). The upper limb tension test: The slr of the arm. In R. Grant (Ed.), Physical therapy of the cervical and thoracic spine. New York: Churchill Livingstone.

Sliders and tensioners

In the early days of neurodynamics, we devised techniques called sliders and tensioners. This was based on the principle that the nervous system is a mechanically continuous structure throughout the body and a clinical search for non-aggressive neural mobilising techniques.

Fig 14.5 From Butler DS 2000 The Sensitive Nervous System, Noigroup, Adelaide

A tensioner is when the nervous system is pulled from both ends. For example, in the slump test, when neck flexion and knee extension, both of which physically load neural tissues are performed together, we refer to this as a tensioner, (i.e. "pulling from both ends"). If the knee is extended and the neck extended at the same time, we refer to this as a slider. The slider is much less aggressive technique. Some people refer to the slider technique as “flossing” as in dental flossing.

Michel Coppieters and I published a paper on this in Manual Therapy, titled- “Do sliders slide and tensioners tension/” (email me if you want a copy). This upper limb cadaveric study on the median and ulnar nerves showed that a slider technique (eg elbow extension with wrist flexion) created much more nerve sliding than a tensioner technique and in comparison, hardly strained the nerves. The suggestion is that mobilising techniques for neuropathic pain states involving peripheral nerves can be made more specific. The gentle but marked sliding of nerves may be extremely therapeutic in aiding early restoration of nerve gliding surfaces and pathways post trauma, and assisting dispersal of inflammatory exudate in gliding pathways.

Introduction

NOI group began in 1989 and went international after the publication of David Butler’s book “Mobilisation of the Nervous System” and the establishment of teaching faculties in the US, Canada, German speaking Europe, United Kingdom, Italy and Australia.

Essentially the entire nervous system is a continuous structure and it moves and slides in the body as we move and the movement is related to critical physiological processes such as blood flow to neurones. This movement is quite dramatic and it is not hard to imagine that fluid such as blood in the nerve bed, a constricting scar, inflammation around the nerve or a nerve having to contend with arthritic changes or proximity to an unstable joint could have damaging effects, some of which could lead to pain.

There are numerous seminars worldwide on neurodynamics and NOI produce the resources The Sensitive Nervous System and NOI DVD and handbook.