Peripheral nerve injury

Vitalstatistix:

· Nerve injury may become apparent days or even weeks later

· Paraesthesia common: 15% of blocks. 99% resolve within 1 year.

· Permanent injury rare (2.4 per 10k regional blocks) but often devastating

· Ultrasound guidance does not seem to reduce incidence of nerve injury

Types of injury:

	Description	Treatment	Prognosis
Neurapraxia	Myelin damaged	Nothing	Good
Axonotmesis	Axons transected	Maybe surgery	Depends if endoneurium cut
Neurotmesis	Whole nerve transected	Surgery	Poor

Most commonly injured nerves:

Ulnar nerve	· Pressure · Stretch: elbow flexion
Brachial plexus	· Compression · Stretch: shoulder abduction,posterior displacement, external rotation · Needle trauma
Lumbosacral nerve roots	· Vaginal delivery with shoulder dystocia
Spinal cord	· Neuraxial procedures

Cause of injury:

· Needle trauma

· Drug toxicity

· Stretch

· Compression

· Tourniquet

· Underlying disease

Approach to the patient with apparent nerve injury:

Open disclosure	· I don’t yet know what the cause is, but it could be the local anaesthetic injection · I don’t yet know whether it’s going to get better · We will find all this out by examining the body part, getting tests, and getting an opinion from a specialist
History	· Sensory disturbance (less vs more vs abnormal vs pain vs none) · Motor disturbance · Time course
Examination	· Full neuro exam · Establish distribution of injury
Investigations	· +/- NCS · +/- MRI
Referral	· Neurologist