classification and diagnostic methods of peripheral nerve injury

classification and diagnostic methods of peripheral nerve injury by Dr. Bipul Borthakur

1. Peripheral nerve injury. By: Dr. Bipul Borthakur , Professor Dept. of Orthopaedics,SMCH

2. Anatomy of Nerve. Cellular components – Neurons, - cell body and axons.

3. Anatomy of nerve (contd.) Connective tissue- a. Epineurium- surrounds the nerve. b. Perineurium - surrounds the fasicle c. Endoneurium- around the axon.

4. Etiology of peripheral nerve injury. Trauma. Ischaemia. Metabolic or collagen diseases. Malignancy. Infections. Radiation. Thermal. Chemical Mechanical.

5. Primary injury- Results from trauma that injures bone or joint. Secondary injury – Results from involvement of nerve by infections, scars, vascular complications, ischaemia, AV fistula or aneurysms.

6. Classifications of peripheral nerve injury. SEDDON CLASSIFICATION SUNDERLAND CLASSIFICATION

7. SEDDON CLASSIFICATION This classifications was described by Sedon in 1943. He divided nerve inury into 3 groups 1. Neurapraxia. 2.Neurotmesis. 3.Axonotmesis.

8. Neurapraxia Physiological inury to the nerve. No anatomical damage is present. Paralysis is transient. Sensory loss is light. Temporary loss of motor conduction. No conduction occurs across the area of injury. Prognosis is good.

9. Axonotmesis It is interruption of nerve fibers within their sheath. Loss of conduction but the nerve is in continuity. Neural tubes are intact. Wallerian degeneration distal to lesion and few millimeter retrograde.

10. Neurotmesis Division of nerve trunk. Rapid wallerian degeneration. Destruction of endoneural tubes seen. Scarring prevents regeneration of axons.

11. Sunderland classification. Classification based on the severity of nerve injury. Divided into First – degree injury. Second- degree injury. Third- degree injury. Fourth – degree injury. Fifth- degree injury.

12. Classification First – degree injury - 1. Similar to neuropraxia. 2.Physiological block at the site of injury. 3. Axon is not disrupted. 4. Best prognosis. 5. Complete recovery within a few weeks.

13. Classification (contd.) Second degree injury – 1.Disruption of axon. 2. Integrity of endoneural tube is maintained here. 3.Wallerian and retrograde degeneration from the point of injury. 4. Corresponds to axonotmesis. 5. Good chances of recovery.

14. Classification (contd.) Third- degree injury – 1.Axonal disruption with endoneurium disruption. 2.Scar tissue formations prevent further regeneration of nerves. 3. Chances of motor and sensory recovery but with deficit. Fourth – degree injury – 1. Disruption of perineurium and some part of epineurium . 2. Poor chances of recovery. 3. Surgical intervention essential for some recovery.

15. Fifth – degree injury – 1. Complete transection of nerve. 2. Seen mainly with open wounds. 3. No possibility of neural recovery without surgery.

16. Diagnosis of peripheral nerve injury. Clinical diagnosis 1 . In the upper extremities :- a. Loss of pain perception at the tip of little finger indicates ulnar nerve injury. b. Loss of pain perception at the tip of index finger indicates median nerve injury. c. Inability to extend the thumb in hitchhiker sign indicates radial nerve injury. 2.I n the lower extremities :- a. Loss of pain perception in sole of foot indicates sciatic or tibial nerve inury. b. Inability to extend the great toe or foot indicates peroneal or sciatic nerve injury.

17. Diagnostic tests IMAGING :- 1. High resolution ultrasound and MRI can accurately assess the physical integrity of the nerve immediate after injury. 2. Provide valuable information regarding surgery decision making. 2. Both intraneural and perineural Injuries can be identified by these techniques.

18. Diagnostic test (contd.) Electrodiagnostic studies :- 1.The best and most accessible correlative electrophysiologic confirmations of a peripheral nerve injury are nerve conduction and electromyographic mapping. 2.The presence, location, severity and possibly prognosis of the neural insult can be determined from these studies. 3.Information regarding recovery pattern can be identified if the test are done sequentially over time.

19. Diagnostic test(contd.) Nerve conduction velocity test:- 1. Orthodromic motor and antidromic-orthodromic sensory studies and retrograde studies (e.g F wave studies). 2. F wave study are especially used for investigating peripheral nerves that are more proximal and less accessible through other techniques.

20. Diagnostic test(contd.) Electromyography(EMG) In an EMG a thin needle electrode inserted into muscle and its activity at rest and in motion are recorded. Reduced muscle activity indicate nerve injury.

21. Diagnostic studies(contd.) Tinel sign :- 1. Gentle percussion by a finger or by percussion hammer along the course of an injured nerve. A transient tingling sensation should be felt by the patient in the area of an injured nerve rather than the area percussed and the sensation should be present for several seconds after stimulation. 2. Positive tinel sign is presumptive evidence that regenerating axonal sprouts that have not attained complete myelinization are progressing along the endoneural tube.

22. Diagnostic test(contd.) Sweat test :- The degree of sweating within the autonomous zone of nerve injury suggest that complete interruption of nerve has not occurred. Ninhydrin print test is another method of assessing sweat patterns in hand.

23. Diagnostic method (contd.) Skin resistance test :- 1.Richter dermometer is used here 2. Autonomous zone of absence of sweating shows an increase resistance to passage of electric current. Electric stimulation test :- 1. Give early evidence of denervation after injury and are useful for following reinnervation of nerve injury, which is less easily assessed by other methods.

24. THANK YOU “ na jāyate mriyate vā kadācin nāyaṃ bhūtvā bhavitā vā na bhūyaḥ ajo nityaḥ śāśvato’yaṃ purāṇo na hanyate hanyamāne śarīre ” “The soul is never born, it never dies having come into being once, it never ceases to be. Unborn, eternal, abiding and primeval, it is not slain when the body is slain .”