2. Overview Of Nerve Injury And Repair Ramy El Nakeeb, MD

3. Nerve anatomy Causes of injury Diagnosis??? Indications and contraindications of nerve repair Factors that affects results Methods of nerve repair,, what is classical, what is new??

4. From a hand surgery perspective, peripheral nerve lesions constitute one major reason for severe and longstanding impairment in hand function. The situation is frustrating because although a nerve suture may be technically perfect and the rehabilitation carried out meticulously, the outcome is unpredictable and sometimes disappointing.

5. The problem A nerve injury differs from most other types of tissue injury in the body since not only a local repair process is required. Transection of axons has implications for the whole length of the neuron (i.e., all the way from the nerve cell body at the spinal cord or dorsal root ganglion level to distal targets) and the repair process involves outgrowth of neurites over very long distances.

6. Anatomy Of Peripheral Nerves Peripheral nerves have four basic components: 1.Neurons 2.Schwann cells 3.Connective tissues 4.End-organs (motor end plates, sensory, and autonomic receptors).

8. Nerve anatomy

9. Causes of nerve injury 1. Mechanical forceInjection injurySharp instrument’s injury Iatrogenic injury

10. Classification of nerve injury Seddon proposed a classification scheme for nerve injuries consists of neurapraxia, axonotmesis, and neurotmesis. Sunderland expanded this classification by subdividing axonotmesis into 3 subtypes.

11. Neurapraxia Nerve not working Refers to a local conduction block. The continuity of axons is preserved, as is the excitability of nerve structures distal to the lesion.

12. Axonotmesis Axon cutting The axon is severed, its distal portion degenerates. Sunderland classification Type II : Axon severed; endoneurial tube intact Type III Endoneurial tube torn Type IV : Only epineurium intact

13. Neurotemesis nerve cutting There is interruption of continuity of all elements of a nerve. N.B: 1. Grade VI injury by Mackinnon 2. longitudinal patterns of injury

14. The Brachial Plexus Rupture: refers to a tear in one or more nerves of the plexus, at a point away from where the nerve attaches to the spine. Avulsion: It occurs when the nerves are torn away from the spinal cord. Neuropraxia: The most common nerve injury. Neuroma: refers to scar tissue that has grown around the injuried nerves. This scar tissue may exert pressure on the injured nerve thereby blocking signals to the muscles.

15. Course of Wallerian axon degeneration. Wang J T et al. J Cell Biol 2012;196:7-18 © 2012 Wang et al.

17. The indications for operating on nerves after an injury include the following:

18. 1. Deep paralysis after a wound over the course of a major nerve or after an injection close to the course of that nerve

19. 2. Deep paralysis after closed traction injury of the brachial plexus

20. 3. A nerve lesion associated with fracture or dislocation requiring urgent open reduction and internal fixation

21. 4. A nerve lesion associated with an arterial injury

22. 5. Worsening of nerve injury while under observation ( acute carpal tunnel) 6. Failure to progress toward recovery in the expected time after a closed injury 7. Failure to recover from conduction block within 6 weeks of injury 8. Treatment of painful neuroma

23. The Reasons not to proceed to repair of a transected nerve include the following:

24. 1. The general condition of the patient. After having saved a life or limb by means of successful arterial repair, the patient, the anesthetist, and the surgeon may well have had enough.

25. 2. The risk of local or systemic sepsis. If local soft tissue damage and contamination from an open fracture or high-velocity gunshot wound is severe.

26. 3. Skilled surgeon not available. 4. specialized equipment 4. specialized equipment not available.

27. 5. When the condition of the nerve is such that function will more surely and more rapidly be restored by musculo­tendinous transfer.

28. The Dream The Truth

29. Result following nerve injury and repair is dependent on factors such as : 1.the extent of nerve cell survival after the injury 2.the rate and quality of axonal outgrowth. 3.the orientation and specificity in growth of regenerating axons. 4.the survival and state of end organs, and cortical reorganizational processes in somatosensory and motor brain cortex.

30. Factors that affect Decision Making: Age Distance between injury and end organ Gap of injury Mechanism of injury Severity of injury Presence of pain

31. Methods of nerve repair Neurolysis Direct suture Nerve graft Neurotization

32. Neurolysis Definition Internal and external neurolysis Indications on internal neurolysis Neurolysis Vs nerve grafting