Adverse Neurodynamics

Question 1

Name some indications that pathology may include peripheral nerve involvement.

Answer 1

i) pain is radiating/radiculopathy
ii) positionall (“spontaneous”) and common movement aggravators
iii) burning, numbness, shooting quality
iv) neurofatiguable weakness
v) sensory changes

Question 2

Explain what is meant by the term mechanosensitivity.

Answer 2

When exposed to mechanical stresses, periperal nerves increase in mechanosensitivity. This means symptoms are easier to reproduce (lower threshold) when the nerve is under the same stresses.

Question 3

List three mechanical stresses that can produce symptoms in a peripheral nerve.

Answer 3

i) tension
ii) compression
iii) friction

Question 4

Explain what a mechanical interface is with regard to neurodynamics.

Answer 4

Areas where nerves contact other structures. In these areas they can be compressed by these structures or tethered to them. Ex. flexor retinaculum and median nerve, fibular head and common peroneal nerve.

Question 5

List the three membranous layers of a peripheral nerve in order from superficial to deep.

Answer 5

i) epineurium (separates fascicles)
ii) perineurium (surrounds fascicles)
iii) endoneurium (separates fibres)

Question 6

Name three key identifiers of the epineurium.

Answer 6

i) facilitates gliding between fascicles
ii) consist of longitudinally aligned collagen
iii) highly reactive to injury

Question 7

Name three key identifiers of the perineurium

Answer 7

i) consists of collagen and elastin
ii) diffusion barrier
iii) mechanical barrier to external forces

Question 8

Name two key identifiers of the endoneurium.

Answer 8

i) consists of collagen

ii) maintains environment around nerve fibre (requires positive pressure!)

Question 9

What factors contribute to variation of clinical presentation in peripheral nerve pathology.

Answer 9

i) vascular considerations (pressure gradient)
ii) mechanical considerations (friction, compression etc.)
iii) influence on axoplasmic flow
iv) extent of fibrosis

Question 10

Describe the pressure gradient between a peripheral nerve and the nerve bed (surrounds nerve fibre).

Answer 10

P artery > P nerve fibre > P vein > P nerve bed.

Note: changes affect nutrition and nerve health.

Question 11

What are the adverse effects of altered axonoplasmic flow in a peripheral nerve?

Answer 11

i) change in action potential (mechanosensitivity)
ii) altered structural integrity of axon and cell body
iii) trophic changes in target tissue (ex. skin/nails)
iv) compromised nerve conduction

Question 12

What is necessary for normal axonoplasmic flow in a peripheral nerve?

Answer 12

i) adequate blood flow

ii) energy to consume

Question 13

At which sites can fibrosis occur in peripheral nerve pathology?

Answer 13

i) between collagen fibres of a layer

ii) between membranous layers (ex. epineurium)

Question 14

Explain the consequences of peripheral nerve fibrosis.

Answer 14

There will be decreased neural mobility in that area which will affect the neurodynamics of that nerve at other sites.

Question 15

What is the distinction between an intraneural and extraneural pathology?

Answer 15

Extraneural pathologies involve the epineurium (ex. tethering to surround structures). Intraneural pathologies Intraneural pathologies involve structures within the nerve (ex. demyelination, neuroma).

Question 16

How are extraneural and intraneural pathologies assessed, respectively?

Answer 16

i) extraneural pathologies are assessed by neurodynamic testing
ii) intraneural pathologies are assessed by conduction tests AND/OR neurodynamic tests (alter elasticity). However, conduction and is more commonly affected.

Question 17

If a patient presents with combined intraneural and extraneural pathology, which should be addressed first?

Answer 17

Whichever is the predominant cause of disability. Although, both will need to be addressed eventually.

Question 18

Explain what is meant by the term “double crush syndrome”.

Answer 18

An injury in one area of a nerve pathway increases sensitivity and likelihood of symptoms in another area of the pathway (ex. C6 dermatome and carpal tunnel syndrome).

Question 19

What constitutes a positive with regard to neurodynamic testing?

Answer 19

i) pt resistance to further ROM
ii) reproduction of symptoms
iii) asymmetrical ROM restriction on affected side

Question 20

Why are sensitivity and irritability particularly relevant in assessing and treating nerve pathology?

Answer 20

Latency effect: nerve tissue symptoms often peak long after mechanical stress is applied.

Question 21

Describe techniques to minimize the risk of causing an adverse latent effect.

Answer 21

i) start with area of nerve pathway well removed from area of symptoms
ii) avoid mobilizing into symptom production
iii) always follow up and modify HEP as needed

Question 22

Explain what a “slider” treatment technique entails. When is it indicated?

Answer 22

Movements of the body that primarily induce movement of a peripheral nerve relative to its surroundings. This allows for larger excursion and lesser strain on the nerve. This is indicated if there is resistance to movement moreso than tension intolerance.

Question 23

What are the benefits of neural “sliding” techniques?

Answer 23

i) dispersion of inflammatory products

ii) limit fibrotic changes (theoretical)

Question 24

Explain what a “tensioner” treatment technique entails.

Answer 24

Movement of the body that primarily induces tension on the nerve. This increases strain on the nerve thereby increasing intraneural pressure.

Question 25

Which mobilization grading system is best used for oscillatory neural treatments?

Answer 25

Maitland.

Question 26

What are the benefits of neural "tensioning" techniques?

Answer 26

i) improves nerve hydration and nutrition ii) stimulate circulation (pumping effect) to reduce intraneural swelling iii) most useful in the chronic stages of healing.