Surgical Nerve Injury

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Author:
xbecx10
ID:
248537
Filename:
Surgical Nerve Injury
Updated:
2013-11-24 14:09:11
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Surgical Nerve Injury IntrotoSurgery
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Dr. Meyer INtro to Surg
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  1. Are all surgical nerve injuries a form of peripheral neuropathy?
    Yes
  2. Are all peripheral neuropathies a form of surgical nerve injury?
    NO
  3. Nerve Injury:
    (1) A localized (not systemic)

    (2) peripheral  (not central)

    (3) symptomatic neuropathy that impairs some or all nerve function

    (4) caused by YOU in the operating room (iatrogenic damage).
  4. How are some nerves damaged endogenously?
    • Congenital
    • Neoplastic
    • Metabolic
  5. Ex. of endogenous Congenital nerve damamge
    –Anomalous development

    –Overuse
  6. Ex. of endogenous Neoplastic nerve damamge
    –Varix

    –Ganglion cyst

    –Lipoma

    –Schwannoma

    –Metastatic infiltration
  7. Ex. of endogenous Metabolic nerve damamge
    –Diabetes


    –RA or other connective tissue diseases

    –PVD

    –Thyroid disease

    –Dyslipidemia

    –Drug toxicity
  8. How are nerves damamge exogenously?
    • Traumatic
    • Iatrongenic
    • Infectious
  9. Ex of endogenously damaged nerves: traumatic
    –Laceration

    –Blunt trauma

    –Fracture/dislocation

    –Traction

    –Injection
  10. Ex of endogenously damaged nerves: Iatrogenic
    –Tourniquet

    –Surgical positioning

    –Casting or bandaging

    • –Surgical technique
    •       •Dissection, handling, suturing
  11. Ex of endogenously damaged nerves: Infectious
    –Local abscess

    –Postinflammatory fibrosis
  12. Other ways nerves can get damaged:
    • Compression
    • Inflammation
    • Direct Injury
  13. Nerve Damage: Compression
    • •Something you create in the operating room
    • –Scar, Suturing, Tourniquet, etc


    • •Something you create in the post-operative period
    •      –Casting, Bandaging, Surgical positioning, etc
  14. Nerve Damage: Inflammation
    •Acute Stretch

    • •Post-operative edema 
    •       -will cause damage to nerves.
    •       -Pain in post op because as soft tissue stretches out, the nerves will get stretched

    •Infection…post op inflammation
  15. Nerve Damage: Injury
    •Laceration

    •Blunt Trauma

    •Traction

    •Injection…don’t want to hit the nerve but as close as you can get to it
  16. HJ Seddon “Classification” of nerve injury
    •Neurapraxia
    –Conduction deficit without damage to the axon

    Least severe: contusion/compression

    –Temporary nerve injury like when your arm falls asleep. As remove force, goes away
  17. HJ Seddon “Classification” of nerve injury
    •Axonotmesis
    –Axon damage without endoneurial tube damage

    –Degeneration of the axon distal to the injury (Wallerian degeneration)

    –Nerve is preserved but the surrounding axon and nerve fibers are damaged

    –Relatively permanent damage

    –May cause muscle atrophy
  18. What is Wallerian degeneration
    happens to nerve distal to injury.

    Proximal is ok but thenerve distal has some type of damage.

    • The metabolism of the nerve gets messedup.
    • Sensory or motor function stops working as well.

    Ex: motor nerve supplying a muscle, muscle looses its innervation and muscle atrophy occurs
  19. HJ Seddon “Classification” of nerve injury
    •Neurotmesis
    –Nerve severance with complete disruption of the endoneurial tube

    –Most severe:  Irreversible with muscle atrophy
  20. HJ Seddon “Classification” of nerve injury

    • •1st Degree
    • –Axon is preserved with temporary conduction block
    • -neuropraxia

    • •2nd Degree
    • –Axon is (reversibly) damaged, but endoneurial sheath is preserved
    • -axonotmesis

    • •3rd Degree
    • –Axon and endoneurial sheath are damaged, but fasciculi (perineurium) are intact
    • -axonotmesis

    • •4th Degree
    • –Nerve fascicule is destroyed and only held together by connective tissue
    • -axonotmesis
    • -no regeneration

    • •5th Degree
    • –Complete loss of nerve truck continuity
    • -neurotmesis
    • -no regeneration
  21. What Nerve Injury Classifications can you get regeneration back?
    • 1st degree: complete in 3-6 wks
    • 2nd degree: complete at 1mm/day
    • 3rd degree: incomplete at 1mm/day
  22. Relevant Peripheral Nerve Anatomy
    -The axon is the functional part of the nerve with the myelin assisting in conduction.

    • -Almost everything else is connective tissue of some form (12-70%)!
    •      -The primary functions of this complicated connective tissue structure are to give the nerve tensile strength, elasticity and protection against compression.
  23. What supplys the epinenurium?
    • Lg nutrient vessels
    • longitudinal fashion
  24. What gives vascualr supply to the individual fasicles?
    capillary network
  25. What contributes to "differential paralysis"/"mixed nerve"?
    Communication between fasicles
  26. internal nerve injury
    • Intraneural fibrosis disrupts the myelin sheath,
    • alters conduction and  inhibits axon remyelination.
    •   -Distal Wallerian degeneratio
  27. external nerve injury
    • Extraneural scarring and adhesions (perineural
    • fibrosis) exacerbate symptoms anddisrupt the blood supply to the epineurium.
  28. Common Peroneal Nerve
    • •L4, L5, S1
    • •Deep Peroneal Nerve
    •       –Motor
    •       –Sensory
    • Superficial Peroneal Nerve
    •       –Motor lateral compartment then to the
    • deep fasia
    •       –Sensory. medial dorsal cutaneous
  29. Posterior Tibial Nerve
    • L4-S3
    • *most important-- broadest reach in terms of motor and sensory function
    • -Motor
    • -Sensory

  30. Sural Nerve
    • L5, S1, S2
    • motor
    • sensory
    • lateral aspect of the 5th toe
  31. Saphenous Nerve
    • L3-L4
    • Motor
    • Sensoy- primarily
  32. Sensory Nerve Function
    • •Pain
    • •Light touch
    • •Deep palpation
    • •Vibratory
    • •Temperature
    • •Point discrimination
    • •Proprioception
    • •Dermatomesvs. Sclerotomes
    • •Etcetera
  33. Motor Nerve Function
    • Weakness
    • Complete loss of function
    • Atrophy
    • Spasticity
    • Reflexes
  34. Autonomic Peripheral Nerve Function
    • Xerosis
    • Sweat gland dysfunction
    • Endothelial dysfuction
  35. Why would you ask a patient what there foot does in the shower?
    Temperature-- varying autonomic reactions/peripheral nerve injury?
  36. Subjective Physical Exam
    • Pain
    • Paresthesia
    • Dysthesia
    • -sharp, shooting, stabbing, burning, electric shocks, numbness/tingling, dull/aching/weakness
  37. Physical Exam
  38. What is Tinel's sign?
    Palpation in Nerve injury exam when there is distal radiation
  39. What is the valleix's sign?
    physical exam of nerve injury-- radiation proximally
  40. Where are the intermediate dorsal cutaneous nerves the most superficial?
    long anterior aspect of the ankle
  41. Why/How would you do a diagnostic peripheral block?
    Isolate a single spot and inject the area with a local anesthetic or one with corticosteroid and when it wears off, spy toms come back
  42. Nerve Conduction Studies
    • measure the VELOCITY at which a nerve is transmitting a signal
    • abnormal or entrapped= decreased velocity
  43. EMG
    • measure AXON POTENTIAL from a muscle innervated by a nerve
    • NOT a specific diagnosis
  44. Ultrasound for Nerve injury
    shows pathology within the nerve
  45. MRI
    better for showing inflammation around a nerve
  46. Conservative modalities for general interventions
    –Off-loading

    –Pills

    • –Injections
    • •Anti-inflammatory
    • •Sclerosing

    –Pain Management consultation
  47. Surgical Modalities
    • -Neurolysis (ext or int)
    • -Neurectomy
  48. Off-loading
    • Casting
    • Padding
    • Strapping
    • Orthotics
    • Shoegear
  49. Pills to treat nerve injury
    -NSAIDs  

    -Anti-convulsants (Neurontin, Lyrica)

    -Tricyclic anti-depressants (Cymbalta)

    -Topical Anesthetic and Analgesic patches

    -Topical capsaicin (hot peppers!!!)
  50. Injections
    • local
    • corticosteroids
    • 4% sclerosing alcohol
    • - try to shrink nerve so it won't get the signal
  51. Pain Managment
    -Peripheral nerve stimulation

    -Acupuncture– not for everybody but if it works, it works well and right away

    -Physical therapy

    -Multimodal intervention
  52. What is external neurolysis?
    • "free the nerve without touching the nerve.”:
    •      -Physically remove scar tissue and place in a better environment Releasing the nerve what it is trapped in.
    • never actually penetrate the epineurium.
  53. What is an internal neurolysis?
    • actually incise through the epineurium to free up individual fascicles:
    •      -Remove "internal" impeding anatomy
    •      - Must be done with loupes or microscope
    •      -Fairly rare undertaking for most podiatric surgeons
    •      -Technique tips
  54. What is a neurectomy?
    • Physically transect the nerve proximal to the pathology.
    •   -How to transect?
    •   -What to do with the stump?
    •   -Buried vs. epineurium
    •   -Paresthesia and stump neuroma concerns
  55. What is a common nerve for a neurectomy?
    Sural nerve

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