Q&A Time! | Modern Manual Therapy Blog

Q&A Time!

Today's Q&A is about Neurodynamics.

Q: My mentor and original Norwegian training both have stated "stretching" a nerve is not a valid/safe treatment. Why do you recommend this in the context of Neurodynamics?

A: That is a great question that I forget needs to be answered every once in a while to those with that training. Coming from a Paris background myself initially, I was told by a faculty member grading my case report that "you should never stretch a nerve!" She asked if I only used the median nerve test as only a test. I sheepishly stated "yes..." A little white lie. I did use it as a treatment as well, with good effect to help resolve the radiating arm complaints.

The current concept of Neurodynamics takes into account the peripheral nervous system, and the central nervous system. For brevity, and because the CNS is covered A LOT on this blog, we'll just tackle the PNS today.

Starting at the nerve root, there should be excursion within the foramen with spinal and extremity movements. The actual peripheral nerves themselves should slide and glide within the tissues and bones they travel through. This is referred to as "the neural container."  The myelin itself is innervated, yes, nerve is innervated, by nervi nervorum. That means it can refer pain, like any other innervated structure.

Studies starting within the last decade (referenced in The Sensitive Nervous System) identified an entity which was coined an "AIGS" or abnormal impulse generating system. The AIGs can generate impulses both proximally and distally from it's location. It is not necessarily the painful site. It is often found under junctional areas like the CT junction, or restricted areas like a pronator teres. Restrictions to nerve sliding/gliding can wear the myelin sheath, which then causes extra ion channels to form. These ion channels are mechanosensitive, chemosensitive, and temperature sensitive.


  • stretch
  • compression
  • cortisol
  • adrenaline
  • "inflammatory soup" from acute injury
  • heat
  • cold
Some or all of these can cause an AIGs to fire. This is a newer concept and takes into account the movement of all the tissues/joints that surround the nerve. It replaces the "double crush."

Tests like the Neurodynamic movements for the upper and lower body have bias for particular peripheral nerves using their sensitizing components. These are based on the anatomical path of the nerve and may include cervical and lumbar movements (or both as in slump testing). These tests can be used as assessments only for restrictions, or as treatments. 

Since I currently do IASTM and functional release to the neural container, I find pre and post testing of Neurodynamic mobility often results in rapid changes to what was previously very restricted. I then give the neurodyanamic tensioner or slider as a HEP for the patient to maintain the new stretch/movement tolerance gained with treatment.

If you are so inclined to use them as treatments, i.e. if the patient does not tolerate STM or JM or either are contraindicated, you should use MDT rules for patient response. It is ok if a treatment increases complaints, which in this case is common, even peripheralization, as long as it does not remain worse. Butler himself says he loves paraesthesia! It's his nervous system reminding him he's alive! Our nervous system within our CT and joints is supposed to move fluidly, and we are just using these sensitizing maneuvers to restore that natural motion. You can be very creative with the neurodynamics and oscillate at any joint, or combine treatments and use STM in neural load, or JM in neural load. These are demonstrated in some of my videos. 

I hope this helps those of you with Norwegian or New Zealand based training who learned "never" to stretch a nerve. To me, that is like saying you should never extend a lumbar spine, never do a thrust manipulation, or not bother working on innert tissues like fascia. They all have there place in a OMPT toolbox.


  1. Chris Dukarski,PTMarch 14, 2012 at 4:28 PM

    Thanks for the info. As you know, I am Norwegian trained. I would like you to address this topic from an evaluative and clinical decision making standpoint ie determing an adequate functional diagnosis. In the Norwegian system, we use manual traction as both a treatment and as a means of differntial diagnosis. If you are performing a nerve sensitizing maneuver or "nerve tension test" and produce peripheral pain or the patients "comparable sign", then how do you interpret your findings if the peripheral symptoms are alleviated via central manual traction?

  2. At uni I was always taught that technically you 'can't stretch a nerve' but it doesn't necessarily mean you shouldn't use loading of a neural structure as a manual technique - as long as you respect irritability, symptoms etc. You can always just deload and use a slider technique in those nasty cases, and progress sliders by increasing the tension proximally eg. neck flexion.

    Favourite tensioner/party trick at the moment is the long leg distraction SLR that was posted here a few months back.

  3. I do not often come up with a diagnosis per se, unless there is a definitive injury like R/C tear, ligament sprain, meniscal tear... and even then I use MDT classification (but not all treatments). Classifying patients has been shown to have better outcomes because the classification leads to treatment under certain systems.

    For your purposes, under evaluation, a positive test would be either a comparable sign, or ANY other sign of change involved to uninvolved. That difference may be ROM, or peripheral symptom that is not felt on the uninvolved side.

    I do no use spinal compression or distraction, in fact, I do not use any special tests that do not lead me to an exercise or manual technique. However, that would be similar to a cervical SB away and having the symptoms increase or ROM decrease for an upper limb neurodynamic test. Just more confirmation that there is a neurodynamic limitation. I don't use manual traction, because I have no traction in my practice, and very few patients need it for home.

  4. I am very surprised that with your extensive training you have not utilized the diagnostic capability of manual traction. By no means am I being pompous in this assertion. Merely, surprised. In the Norwegian system, we use it to determine whether a peripheral joint problem is intra versus extraartucular or whether peripheral systems can be alleviated with central decompression. This guides us in our ability to accurately determine a functional diagnosis. Your McKenzie training nor your Evidence in Motion training advocates this approach? Of course, there are many ways to skin the proverbial cat. McKenzie versus Norwegian. So, I ask you again, what would your interpretation be if I placed an upper extremity in a nerve sensitizing position, produced my patient's comprable sign, provided cervical manual(not mechanical), and had the patient experience a complete relief of pain? Would you still advise nerve mobilization and why?

  5. MDT chiefly uses repeated motions to end range which are osteokinematic (extension, flexion, SB, rot) and not arthrokinematic, like traction. Some of their treatment techniques for cervical spine and variations by Mulligan for lumbar spine involve traction. I also do not have training for EIM, but I do mentor for them, as I understand it in communication with some of my future mentees, they are Maitland based.

    Sorry not to answer your question directly the first few replies and with the Q&A, guess I didn't understand it.

    My interpretation would depend on whether or not the complete relief of pain lasted. If the relief of pain remains after the traction (along with increased neurodynamic mobility), I most likely would not use the neurodynamic motion as a treatment. However, if the relief occurred only during the manual traction, and the ROM improvement and pain relief was transient, then I would continue to use the neurodynamics as a treatment.

    A real nerve head may still use the neurodynamic treatment to ensure neural mobility within the container and then also check cervical SB toward and away to see if it has any effect.

  6. You can "stretch" a nerve like any other structure, whether or not it deforms plastically would be another matter. The "nerve mobilization" has been replaced with neurodynamics to include sliding, gliding, along all the relevant tissues. While we still bias different peripheral nerves and elicit different responses via components, we no longer use "stretching" when it comes to nerves, or muscles (and fascia for some).

  7. Hey again! Back from SanFran. I just wanted to pick your brain again regarding the manual traction. I have read Butler's Sensitve Nervous System and he also is not a big advocate of traction. He never even mentions the diagnostic capability of manual traction. He does, however, mention at 3 separate points in the book(the epilogue included) that manual traction could be used as a treatment if the problem stems from the nerve root ie there is a centrally mediated problem such as a disc derangement. In the Norewegian system, if we can alleviate central or peripheral symptoms either partially or completely using manual traction AND we can glide the nerve proximally and distally using neurdynamics testing then we diagnostically consider this a centrally mediated problem with proper neural dynamics. Therefore, neural mobilization would NOT be an appropriate choice of treatment because, in the view of the Norwegian system, we would further irritate an already sensitized nervous system. Performing central manual traction(lumbar or cervical) in a neural tension position should INCREASE symtoms, not DECREASE symptoms because the traction itself further stretches the neural system. Butler confirms the connectedness of the neural system and this is the premise of all our neurodynamic testing. Right? We treat using intermittent cervical manual traction in combo with appropriate treament of adjacent joint and soft tissue structures. Possibly issue a Saunders home traction unit. Patient education is also a HUGE component in alleviating stress to the spine. Believe me when I say that, in spite of my findings, I have done neural gliding techniques with or without Active Release Techniques and HAVE been able to alleviate symptoms and have improved post testing of neural tension tests. I am at a loss to explain why. Butler certainly tries to with the idea of AIGS, ion exchange, circulatory effects, etc As an educator, how would you explain your rationale to students?? I have been challenged by the traction versus nerve mob concept since 1997. I challenge you to REALLY think about what I have said and try to justify your interventions. Why would you perform neural mob when central traction alleviates symptoms (even temporarily) AND neuro dynamics tests demonstrate prox and distal movement? Would this thought process change your strategy? Try it and let me know.

  8. Chris, I get what you're trying to ask, and tell me to try. But honestly, at any given time at least 75% of my patients are head/neck, many with referred/radicular UE complaints. I have not used traction as a test or treatment in years, yet my success rate remains high, with seeing the majority of my patients for about a 4-6 weeks prior to discharge.

    It would be the same argument I use when anyone asks me why I do not try treatment x or y. If my current approach is making the majority of my caseload better, why would I add it, especially when I'm not going to have a patient obtain a Saunders if I can get them better with manual treatment, MDT, and HEP.

    I rarely use neurodynamics as treatments, and mainly use them as HEP and pre and post treatment mobility tests. I am not formally trained in your approach, but I can see why you use it for diagnostics. I do not think in terms of diagnosis, but classification that leads to treatment, combining the best of MDT, and OMPT treatments. I classify patients as derangements or rapid responders or dysfunction, or slow responders. I also do no special tests unless a patient has history of trauma. Whether it's MDT, or more recently the SFMA, I mainly test movement, and positions, and for me, traction fits into neither category.

    I have told patients to use a Saunders at home, and tried traction as a last ditch effort, and some responded to it and needed it for maintenance. However, this was only a handful in the last 14 years of practice. Many unilateral cervical patients often respond to positional distraction and do not need traction.

    In terms of traction increasing or decreasing symptoms/mobility, Butler hypothesizes a similar situation for cervical SB toward and away. Toward should decrease Sx and increase ROM and away should increase Sx and decrease ROM. The opposite sometimes occurs, he states potentially a nerve root may be sensitized to mechanical deformation and on a spur, further compressed with SB toward, but moved away from the spur with traction by your system or SB away, thus increasing root excursion in the lateral foramen. Perhaps the traction is also opening an bony entrapped nerve also allowing for increased excursion at the root and thus also distally in the UEs. It is also very likely it also just decreases perceived threat, the patient thinks it feels good, and the CNS increases the stretch tolerance to neural loading.

    Hope this helps and does not come across as being too argumentative!