Neurodynamics: A Brief overview
What is neurodynamics?
The body’s nervous system has a mechanical interface via the musculoskeletal system. When you move, your muscles and contractile tissues put non-uniform stresses and movement to your nerves and neural tissues. This causes many different mechanical and physiological responses in your neural tissues. These responses include neural sliding, pressurization, elongation, tension and changes in circulation, axonal transport and impulse traffic. [1]
In a 2008 study, scientists described an effect of mobilizing a nerve on a cadaver. They discovered that performing passive movements increased fluid movement around the tibial nerve. The study found that mobilization techniques could reduce swelling surrounding the nerve. In other words, impaired fluid movement within the nerve sheath could be a factor for the reduced ability of the nerve to slide. [2]
neurodynamic dysfunction
When the ability of a nerve or neural tissue to effectively slide or move along as you move your body is hindered, you may have difficulty or symptoms in certain positions and activities. This can be referred to as neurodynamic dysfunction or neural tension. For example, a runner who has decreased ability to straighten their leg due to neural tension, they will have decreased stride length while running which can potentially lead to a hamstring or calf strain. Another example is a sitting position on a chair or carseat. This can become an issue if the position leads to causing neural tension which can create symptoms of pain in the lower back or buttocks.
Physical therapists use tests during an examination to identify tension or neurodynamic dysfunction. These tests apply tension to neural structures to provoke or reproduce symptoms. If neural tension is identified, then mobilization techniques such as a glide or tensioner can be applied to restore mobility to the affected neural structures. However, it’s important to not only to perform exercises to help manage the problem, but to also look at the underlying movement patterns and causes. For example, gait pattern in running or sitting position as mentioned earlier.
Another common cause of neurodysfunction can be pressure or impingement onto a nerve from surrounding structures and tissues. Disc degeneration or a lesion to the disc can create more pressure or impinge a nerve leading to pain and dysfunction. For example, a bulging disc in the spine may put stress and cause a nerve to become inflamed which could cause issues. Muscle length may also create impingment or pressure on a nerve. For example in piriformis syndrome, a shortened piriformis muscle can impinge on the sciatic nerve.
Sometimes symptoms of a neurodynamic dysfunction can be disguised as a muscle strain or musculoskeletal injury. Recurrent muscle strains may have an underlying neurodynamic factor. It is important to assess neurodynamics as this can be overlooked, and symptoms do not resolve after treatment. Neurodynamic mobilizations can be an important contributor to a return to fitness, along with joint and soft tissue mobilization, and exercises to correct muscle imbalances. A physical therapist will be able to help and guide you in this process.
Written by Daniel Le, DPT
References
Shacklock M. Neurodynamics. Physiotherapy. 1995 Jan 1;81(1):9-16.
Ellis RF, Hing WA. Neural mobilization: a systematic review of randomized controlled trials with an analysis of therapeutic efficacy. J Man Manip Ther. 2008;16(1):8-22.