neural mobilization

NEURAL MOBILIZATION

OBJECTIVES

• Nerve anatomy and physiology• Clinical biomechanics of nerve• Pathomechanics(pathophysiological and

pathomechanical)• Principles of neural mobilization• Demo• Evidence on all NTT

Introduction

• Concept of continuous tissue tract1. Both CNS and PNS need to be considered as one since

they form a continuous tissue tract2. This system is continuous in three ways• The connective tissue is continuous although different

in format (epineurium , duramater). A single axon is associated with number of connective tissues.

• Neurones are interconnected both electrically and chemically.

Introduction cont

The Nervous system• Includes all the neural tissue in the body

Neural tissue • Neurons -- cells that send and receive signals• Neuroglia (glial cells) -- cells that support and protect neurons

Central Nervous System

• Nerve roots are considered to be more a part of central than peripheral nervous system which include meninges , lack schwann cells & receive nutrition from CSF.

• The connective tissue of the nerve trunks are very diff from those of the roots even though the same axon is present in the ventral roots.

• Many authors have drawn attention to the fact that the connective tissue coverings in nerve roots are much weaker, or not present at all(Murphy 1977).

CNS cont.

• Gamble(1964) conducted an electron microscopy study & found the connective tissue of the nerve roots were more like leptomeninges(arachnoid &Piamatter) than that of peripheral trunk.

• Watanabe (1985) using an electron microscope found that each rootlet has a pial layer and it resembled a wispy sheet of gauge.

• There are a no. features at the nerve root level for transmission

CNS cont..

• The fourth, fifth, sixth cervical spinal nerves has a strong attachment to the gutter of respective transverse process.

• At segmental level dural & epidural tissues form a connective tissue sheath which include epidural sheath(Dommisse & Hause et al ).

Beyond the dorsal root ganglion this sheath forms the epineurium & perineurium. These attachments are not immediate as there is no mechanical equivalent to perineurium in nerve rots.

CNS cont…

The epidural tissues and the dura combine to form epineuriuma and the outer layer of perineurium where as the endoneurium is the continuation of the pia(Sunderland 1974, Hanse et al 1985)

• The dural sleeve forms a plugging mechanism which helps in preventing the nerve root being pulled away from foramina but also distributes force.

• Nerve roots have their own inbuilt mechanism for nutrition and protection. CSF does both the activities (Rydevik et al).

The Neuraxis

• The neuraxis (spinal cord ) is the continuation of medulla oblangata and extends app to L2 vertebral level and it tapers to form conus medullaris.

• Breig(1978) notes two methods of neuraxial adaptation to stretch

Unfolding and untwisting as axons straighten Movements in relation to neighbouring vertebral

segments.

The Meninges

o Pia & Arachnoid mater :• These are very delicate membranes far more than

duramater. A mesh or lattice of collagen fibres make up the pia and arachnoid maters.

• This allows stretch & some compression without kinking (Breig 1978) and they protect the neural elements and allowing the movements at the same time.

o CSF, Sub arachnoid &Subdural spaces :• The subarachnoid space contain CSF .

• It acts as a hydraulic cushion surrounding the cord and nerve roots.

o Dura mater• Outermost layer meningeal layer & by far the toughest

and the strongest which contains collagen and some elastin fibres arranged longitudinally (Tinturi).

• This gives the dural theca greater axial strength (Haupt &Stofft ).

Neurodynamics

• Definition : Clinical neurodynamics is essentially the clinical application of mechanics and physiology of the nervous system as they relate to each other and are integrated with musculoskeletal system.

• General layout of the system : Mechanical interface : It is defined as that tissue or

material adjacent to the nervous system that can move independently to the system.

• Neural structures• Innervated tissues The first is that they provide the basis for some causal

mechanisms that therapists should pay particular attention.

The second reason is for making specific reference to the innervated tissues is that they provide the therapists with the opportunity to move nerves.

The third reason is for the treatment basis(Laban et al 1989).

Mechanical functions

• Tension : The first primary mechanical events in the nervous

system is generation of tension. Since the nervous system is attached to each end of the

neural container the nerves are lengthened by elongation.

Perineurium : This is the primary guardian against excessive tension and is effectively cabling in the peripheral nerve(Sunderland 1991).

• Dense packed connective tissue and forming each fascicle this possess considerable longitudinal and elasticity.

• It allows peripheral nerve to withstand approx. 18-22 % strain before failure(Sunderland 1991).

Sliding of nerves : The second event is movement of nervous system relative to their adjacent tissues.This is called excursion or sliding(Wilgis &Murphy 1986).

It is of longitudinal and transverse .

• Longitudinal sliding :The sliding of nerves down the tension gradient enables them to lend their tissue toward the part at which elongation is initiated.

• This way tension is distributed along the nervous system.• For eg. Median nerve at elbow

• Transverse sliding: It occurs in two ways – The first is to enable the nerve to take the shortest

course between two points when tension is applied. The second means by side way pressure by

neighbouring structures such as muscle and tendons. Sliding of peripheral nerve in the nerve bed is

provided by mesoneurium and internal sliding of the fascicles.

• Compression : Neural structures can change their shape when pressure is exerted on them.

• A clinical example ulnar nerve in elbow flexion .• The epineurium is the padding of the nerve and it

protects the axons from excessive compression.• It contains finer and less densely packed connective

which gives them spongy qualities and enables the nerve to spring back when pressure is removed.

How nerves move

Movement of joints :Convergence –The nerves move in the direction of the joint

because that is where elongation is initiated. The effects of the two ends produce little or no movement of the nerves relative to joint roughly at the midpoint.

convergence ocurs in limbs (Smith&Swash 1976) and spine at most mobile segments(C5-6,C4-5) during sagittal movements(Adams&Logue1982).

• Nerve bending: The bending of the nerural structure around

the interface is a good example of the combining of fundamental events to produce a more complex action.

Ex: Ulnar nerve at elbow

• Movement of innervated tissues: In addition to longitudinal forces being applied to

the nervous system from the adjacent to the nerve, the innervated tissues can be used to produce such events.

For instance Dorsiflexion of foot and toes used to apply tension on sciatic nerve.

Movement of interface

• Nervous system responses to movement.

Physiological evenets

• Intraneural blood flow: Blood flow of the peripheral nerves is actually

maintained by nerves(nervi vasa nervorum)(Bove&Light 1995).

Nocioceptors and sympathetic fibres are relevant because in addition to potentially causing pain they release substance P and calcium gene related peptide from their terminals into the walls of the blood vessels(Zochodne & Ho 1991).

• Maintanence of blood flow during movement: During normal movement, nerve blood

flow is preserved through an intricate system of vessels that distort the nerve.

At rest, vessels are coiled and during movement they become uncoiled rather than stretched(Sunderland & Lundborg 1998).

Neurodynamic sliders

Neurodynamic tensioners

Spine

• Mechanical interface • Neural • Innervated tissue

Flexion and extension

• Mechanical interface- Spinal canal Flexion of the whole spine causes elongation of the

spinal neural structures because they, and their canal are located behind the axis of rotation of the spinal segments.

• Neural tissues Tension and strain are the two responses for

flexion. The amount of tension is not clearly known but strain from lumbar extension to flexion in lumbar dura can reach 30%, sacral nerve roots 16%(Adams&Logue; Yuan et al 1988).

• Sliding and convergence Sliding of neural structures is complex in spine

and specific sequences of movements their own sliding. for eg. Neck flexion produces cephalad sliding

of neural structures in lumbar region(Breig 1978). However SLR produces caudad sliding of the nerve roots in the lumbasacral foraminae(Goddard & Reid; Breig 1978).

Lateral flexion and lateral glide

• Mechanical interface The key event with lateral flexion in relation to

mechanical interface is that the intervertebral foraminae close down ipsilateral side and open on the contralateral side(Fujiwara et al 2001).

• Neural effects Lateral flexion produces increased tension in

the neural structures on the convex side of the spine and reduce tension on the concave side(Selvaratnam et al 1988).

Increase in tension occurs in two ways : The first is that lateral flexion itself produces

elongation of the interface and neural tissues on the convex side.

The second is by causing an increase in distance between the spine and the periphery by sideway translation of the vertebrae(Louis 1981).

Uses :1. Structural differentiation.2. Sensitization.

Others

• Contralateral neurodynamics.• Bilateral neurodynamic techniques.

General Neuropathodynamics

Mechanical interface dysfunctions

Innervated tissue dysfunctions

Mechanical interface dysfunctions

Closing dysfunctions

•Reduced closing•Excessive closing

Opening dysfunctions

•Reduced opening•Excessive opening

Pathoanatomical dysfunctions

•Eg .Spondylolisthesis•Malignancy

Pathophysiological dysfunctions

•Inflammation

Closing dysfunctions

• Reduced closingSymptoms : Key behavioural aspect is symptoms increase with closing

movements.Physical findings: 1. Posture : In acute and severe dysfunctions a protective deformity is

frequently apparent. This deformity is always in the opening direction so as to reduce pressure on the adjacent neural structure

• Excessive closingSymptoms :• Provoked by closing mechanism.• Hypermobility, instability or habitual closing exist. Eg. Hyperlordotic lumbar spine.History :• Habitual posture or posture imperfection is common.• Sometimes a history of trauma and features of instability also instability

Opening dysfunctions

• Reduced openingSymptoms :• Usually aches and pains in the localized area with or without

referred pain.• Opening movements provoke pain and are usually restricted.History :• Usually history of trauma exists in which patient has been forced

into opening positions.• The body then compensated during healing process to produce

inflammation and muscular bracing such that opening movements are reduced to avoid further provocation.

• Eg. Spine

• Physical findings: The reduced opening dysfunction produce a protective

deformity on the ipsilateral side unlike closing type has on contralateral side.

This deformity is specially designed to reduce tension in the interfacing and neural tissues.

• Palpation : Tenderness, muscle tightness and thickening. Eg. L4-S1 segments may be accompanied by tenderness and

tightness of ipsilateral erector spinae as they limit contralateral flexion.

• Excessive openingSymptoms :• Aches and pains and can produce referred pain.• Pins and needles ,numbness can occur in this dysfuction.• Symptoms are intermittent and they are produces when provoking

movements are done .Physical findings• No deformity occurs in this type.• Opening movements are increased and that leads to this disorder.• Ex. Cervical region contralateral flexion and rotation.

• Palpation : Tenderness over specific sites is often present. Hypermobilty produces mechanical irritation of

the relevant structures.

Neural dysfunctions

Neural sliding dysfunction

Neural tension dysfunction

Hypermobility

Neurodynamis tests

• What to observe – changes in movement, movement diagram.

• Planning the examination.• Levels.

• Level 0 – neurodynamic testing contraindicated. Any contraindication for manual therapy generally exists for

neurodynamic testing.• Level 1 – limited examination Indications :1.When symptoms are easily provoked and takes long time to settle

after movement.2. In cases of severe pain.3. Presence of any neurological deficit.4.When problems shows a progressive worsening after physical

examinantion

Level 2- Standard examination Indications and contraindications:• The problem is not especially easily provoked and symptoms are

not severe.• Neurological symptoms are absent.• When pain is not severe at the time of examination.• It is contraindicated when problem is unstable, hypersensitive,

irritable or when pathology is present

• Higher level of examination:Indications and contraindications:1. The level 2 testing is normal and didn't reveal sufficient

information.2. Symptoms are stable and not easily provoked.3. When there is no pathology that might adversely affect the

nervous system.4. Contraindications same as level 2.

• General points on technique:• Explanation to patient• Bilateral comparison• Test the unaffected side first• Maintain each movement precisely• Be gentle and donot hurry• Evoke versus Provoke• Short duration of testing.

Standard neurodynamic testing

• Slump test • Straight leg raise• Prone knee bend

Slump test

• Introduction: This is used to evaluate the dynamics of neural

structures of the central and peripheral nervous system from the head, along the spinal cord, sciatic nerve tract and its extensions.

Indications : Headache, pain anywhere in the spine,pelvis and the lower

limb.Preparation: Pt sits with posterior aspect of their against the couch with

their thighs lying parallel. The parallel placement of thighs is for internal consistency(differences in pelvic size of male and female)

Steps in slump

• Level 1: Neurodynamic sequencing Stage 1: If the patient sits without provocation of symptoms,

they adapt the starting position of the slump. However if they cannot sit altering the position is necessary.

In this level thoracic and lumbar flexion is avoided. Instead neck passive flexion and straight leg raise is used.

Stage 2 : neck flexion is performed by the patient while the therapist supports patient forehead to prevent rapid descent of head.

Stage 3 : Dorsiflexion may be performed passively and is followed by passive knee extension.

• Level 3a(neurodynamically sensitized) The level 3a position of the slump test incorporates

additional sensitizing manoeuvres of medial rotation and adduction of hip, dorsiflexion of ankle and contralateral flexion of spine.

SLR• Introduction: The SLR is used to test the movement and mechanical

sensitivity of the lumbosacral neural structures and their distal extensions.

• Indications: It is generally applied in cases of pain and other symptoms in

the posterior and lateral aspect of the lower quarter but its use can be warranted in examination of the thoracic spine.

• Preparation : Pt in supine lying with the body aligned symmetrically .In it

purest form the test is performed without a pillow.

• Method• Structural differentiation proximal symptoms : use dorsiflexion Distal symptoms: hip flexion produces distal symptoms

so further differentiation is required. Active cervical flexion : not required

• Normal response: The normal response to the SLR is pulling and

stretching in the posterior thigh that spreads into the posterior knee and sometimes upper third of calf(Lew& Slater 1988).

• Level 1 : Technique: Pt is in supine lying with straight knee if

possible .Passive dorsiflexion is performed and the limb is raised slowly to the first onset of symptoms.

• Level 3a Technique : the straight leg is raised to the first point of

symptoms, then internal rotation and adduction are performed and dorsiflexion is added at the end.

Treatment giudelines

• Mechanical interface Not to provoke symptoms. Initially performed as atrail for 30-60

seconds.• Neural components sliders : One ended Two ended

• Tensioners : One ended two ended

Lumbar spine and radiculopathy

• Mechanical interface Reduced closing dysfunction : level 1Position -- contralateral side lying with hip and

knee flexed to 90 degree.

Static openers

Dynamic closures

Neural dysfunctions-cephalad