|Peripheral Nerve Enjury
Nerves are very specific tissue responsible for transmitting sensations from brain and spinal cord to targets peripheral body part as well as vice versa.Ionic changes takes place at one cell to another cell there by transmitting signals from one part to another.
Any injury to nerve may lead to loss of function of body part to wchich the nerve was responsible.
CLASSIFICATION OF NERVE INJURY-
NEUROPRAXIA-minor contusion,nerve axis cylinder preserve,complete recovery in few days to weeks.
AXONOTMESIS- Axon breakedown with wallerian degeneration with preservation of schwann cell and endoneriual tube.spontaneous regeneration with good functional recovery.
NEUROTMESIS- complete anatomic severance of nerve,neuroraphy is needed.
NEURONAL DEGENERATION AND REGENERATION-any part of neuron detached from its soma degenerate and is phagocytosed.Degeneration distsl to injury is Wallerian degeneration,and proximal to injury is primary degenaration.more proximal injury more severe is secondary degenaration.
EFFECTS OF NERVE INJURY-loss of Motor,Sensory, Reflex, and Autonomic responses.
ETIOLOGY OF NERVE INJURY-Most common form of nerve injury is post traumatic. Rest causes are thermal, chemical, collegen diseases, malignancies, toxins.
REPAIR OF NERVE-NEURORRHAPHY--- Restoration of nerve should be done as early as possible
Nerves are repaired under microscope using very fine sutures. There are two types of nerve repair one is EPINEURAL NERVE REPAIR and another is EPIPERINEURAL NERVE REPAIR.
FACTORS AFFECTING NERVE REGENERATION- Age-Gape between the two nerve ends-Delay between nerve injury and repair-The level of injury-Conditions of nerve ends-condition of wound/type of injury-experince of surgeon /surgical technique
IMPORTANT FACTORS IN NERVE REPAIR-1.Normal nerve ends 2.Healthy wound. 3.Gentle handling of nerve. 4.Allinment of nerve (without rotational defect) 5.Tension free repair.6.Proper immobilization.
POST OPERATIVE CARE-
Early postoperative Phase-Same as any wound management. Late phase-Physiotherapy for joints*,Electrical stimulation
Return of Function- after crossing repair site nerve regenerate at speed of one millimetre per day. Usually not before two months.*-Evaluate at the end of third month.
Criteria for result analysis- Sensory return, Autonomic response (starch test for sweating), Motor function, Progressive Tenels sign..
FINAL OUT COME----There is always great hope of return of function.