Nerve pathology & rehab Flashcards
Pathophysiology associated with the development of musculoskeletal peripheral neuropathic pain
anything that increases pressure in perinerium can impair axoplasmic flow
Venous congestion Impaired axoplasmic flow > Inflammatory response • Immune cell activation • Intraneural oedema • Further of venous congestion • Further impairment of axoplasmic flow • Fibroblast proliferation & fibrosis • Progressive demyelination • Axonal degeneration > Impairment of impulse conduction related to amount of intraneural oedema & myelin changes
Neurodynamics:
= Nerve elongation & nerve excursion techniques
- a dynamic variation in intraneural pressure when correctly applied may facilitate evacuation of intraneural oedema and reduce symptoms
- nerve gliding exercises may also limit fibroblastic activity and minimise scar formation via normal and early use of mesoneurial gliding tissues
Factors increasing predisposition to a nerve pathology
Systemic
- Diabetes – inc. collagen; inc. cross-sectional area
* Thyroid disease
Factors increasing predisposition to a nerve pathology
Non-systemic
- presence of a nerve disorder is a predisposition for the development of a secondary nerve disorder in the same quadrant “double crush phenomena”
- Axonal transport
- Altered ion channels
- Neuroinflammation
- Central sensitisation
- Altered neural biomechanics
Seddon’s and Sunderland’s classification systems of the pathoanatomy of nerve injury:
Type/Grade 1. Neurapraxia = Temporary conduction block
Type 2. Axonotmesis = endoneurial tube, perineurium andepineurium intact
Type 3. Axonotmesis = endoneurial tube destroyed
Type 4. Axonotmesis = + endoneurial tube & fascicle destroyed, Fibrosis
Type 5. Neurotmesis = Complete transection of nerve
more CT layers compromised when descend layers
Following axonal transection:
- Cell body swells, nucleus moves peripherally = change in metabolic priority from production of neurotransmitters to production of structural materials needed for axon repair and growth
- Degeneration of proximal axon
- Wallerian degeneration starts within 2-4 days of injury
- Schwann cells detach from axons, proliferate & clear cellular & myelin debris
- Schwann cells align longitudinally & express stimulating factors to direct nerve regrowth toward target organ.
Primary repair of nerve transections: neurorrhaphy
primary has better prognosis than delayed
Epineurial repair then Fascicular repair
- Identification of sensory & motor neurons via electrical stimulation or staining.
Nerve grafting:
when primary repair cannot be performed without undue tension.
Autografting:
• sural N, medial antebrachial cut, lateral fem cutaneous, superficial radial N
• graft repair site & graft itself regain the same tensile strength as the native nerve by 4 wks (limb immobilised during this period to protect the graft)
Allografting Synthetic tubes
Preoperative goals in a denervated extremity:
DECREASE STRESS, SUPPORT JOINTS
Protection & maintainenance of range of motion
Bandaging, splinting, ROM exercises to prevent contractures & deformity, support joints, limit oedema, maintain blood and lymphatic flow and prevent tendon adherence.
Direct muscle stimulation to reduce muscle atrophy / psychological benefit
Post-operative goals in a denervated extremity:
stimulate nerve growth, sensory and motor repair,
maintenance of muscles
Early-phase sensory re-education decreases mislocalisation and hypersensitivity and reorganises tactile submodalities, such as pressure and vibration.
Hydrotherapy can be helpful to improve joint contractures and eliminate the effects of gravity during initial motor recovery, thereby enhancing muscular performance.
Biofeedback may provide sensory input to facilitate motor reeducation.
Electrical stimulation
Electrical stimulation increases sensory & motor neuron regeneration
Re-innervation of thenar muscles post carpal tunnel release
Tinel’s sign
A positive tingling sign in response to mechanical stimulation indicates that some regeneration is occurring.
*** The most important clinical information is progression of the sign seen with frequent evaluation of the patient.
- A positive sign that is PROGRESSING signifies that regenerating nerves are able to pass the lesion;
- a sign that is STATIC at the site of injury indicates the presence of a neuroma and the need for exploration.
- In cases of nerve lesions with large anatomical gaps that had a positive tingling sign, a Tinel sign could not be elicited distal to the site of injury.
