Emg for sports medicine providers2010


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  • 4 humors of Greco-Roman Medicine
  • Velocity, amplitude, duration, area, Latency: Bespeaks conduction velocity…how rapidly information can go from point a to point b Amplitude….is a summation of motor unit potentials and reflects the health of the entire nerve bundle
  • Nerve fibers surrounded by endoneurium Fascicles surrounded by perneurium Several fascicles bundled together into Epineurium
  • Suggestive of demyelination or conduction block, however changes must be severe and modern studies suggest there is very limited value to the studies in most circumstances…and the info is less individually diagnostic and more supportive of a diagnosis already being considered.
  • Inc Age= slowed conduction, decreased amplitudes classicaly: decr by 1.5% per year over 65 Newborn = 50% of adult cv, 80% of adult by one year Equal to adult by 3-5 years
  • Amplitude, frequency, duration, rhythm, …..sound quality
  • NCS: Does info travel from a to b and does all the info make it EMG: do the nerves and muscles communicate appropriately…..with normal response from the muscles to voluntary stimulation
  • After an excellent physical exam and additional history taking…………..referral for EMG and possible lumb0/sacral and pelvic imaging
  • Ankle Dorsiflexion =
  • Peroneal sensory distribution: Dark is from common peroneal nerve the lateral cutaneous nerve of the calf. The striped area is the superficial peroneal sensory distribution. The green solid area represents the deep peroneal sensory distribution. All 3 areas shaded would be numb in a patient with a common peroneal nerve lesion.
  • Compound muscle action potential
  • Tinel Sign, Compression test….pronate the foot
  • Adductor longus = obturator but L2-4,
  • After an excellent physical exam and additional history taking…………..referral for EMG and possible lumb0/sacral and pelvic imaging
  • Radiculopathy= intra-spinal…..herniated disc, foraminal stenosis, disc-osteophyte complexes…the DRG is intact since distal to this pathology……however if plexus, distal nerves affected than will see changes on sensory ncs
  • Emg for sports medicine providers2010

    1. 1. A presentation at Children’s Hospital Boston 12/23/10 Stephan Esser MD www.esserhealth.com
    2. 2. EMGfor the Sports Medicine Provider Lower Extremity Mono-neuropathies Stephan Esser USPTA, MD Harvard/Spaulding
    3. 3. Disclosures
    4. 4. Objectives• A Touch of History• Review Basic Neurophysiologic Concepts• Define EMGFU• Explore common LE Mono-neuropathies N• Run some cases• Wrap Up
    5. 5. What it is NOT!• The END of the conversation• A talk on neuropathy management• My recommendations on the selection of
    6. 6. “Animation”• 4 humors: sanguine, melancholic, choleric, phlegmatic• Chi of the Oriental Mystics• Soul of Christianity
    7. 7. 1666: Franciso Redi: Electric Ray1773: Walsh: Eel could generate electricity
    8. 8. A touch of History• 1792: Galvani: Electricity can generate Muscle Contractions• 1849: Dubois-Raymond: record electrical activity from a muscle contraction• 1890: Term Electromyography coined
    9. 9. EMG
    10. 10. Electro-diagnostic Studies• 2 Parts: – Nerve Conduction Studies – Electromyography• Purpose: – Extension of the clinical exam – Identify/Confirm neurologic dysfunction – Localize a lesion • Anterior horn cell, dorsal root ganglion, plexus, peripheral nerve, neuro-muscular junction
    11. 11. Nerve Conduction Studies• Electrodes placed on the skin• Peripheral nerves are stimulated with low intensity electrical impulses• Reference and active sensors then identify characteristics of the electrical wave traveling
    12. 12. Basic NCS• Upper Extremity – Motor: Median (APB), Ulnar (ADM) – Sensory: Median, Ulnar, Radial, (MAC, LAC)• Lower Extremity – Motor: Tibial (Abd Hall.), Peroneal (EDB) – Sensory: Sural, (Superf. Per., Saphenous, LFC)
    13. 13. Sural Nerve
    14. 14. Tibial: AHL
    15. 15. Peroneal: EDB
    16. 16. Endoneurium PerineuriumEpineurium
    17. 17. 12
    18. 18. Peroneal: EDB2 1 A R
    19. 19. Basket of Reflexes• Based on age and height• H Reflex: Monosynaptic spinal reflex – Side to side difference of 60%• F Wave: low amplitude late response reflex – Suggestive in Radicular rule out
    20. 20. Variables• Age• Technical : – Lab norms – Experience – Temperament – Temperature • Velocity reduced by ≈ 2.4m/s/ degree Cel. < 32 (89.6) – Timing • > 3 weeks post injury/ of symptoms – Placement • Too close, too far distorts computer calculations – Preparation • Oily skin/dispersion
    21. 21. Basic EMG/Needle• Sample muscles in affected/tested segment• At least 1 in each major myotome – 5 in UE – 5 in LE – Paraspinals where appropriate
    22. 22. Electromyography Insertional• Needle Electrode Resting• Ground Exertional
    23. 23. In Review• “EMG”: – Nerve Conduction Studies – Health of the Nerves • Sensory • Motor – Needle EMG – Health of the “Relationship” (nerve and muscle) • Insertional • Resting • Exertional
    24. 24. Mono-Neuropathies of the Lower Limb
    25. 25. Case #124 y/o recreational runner presents to clinic unable to raise her right foot.
    26. 26. Differential Diagnosis• Peroneal Neuropathy• L5 Radiculopathy• Sciatic Neuropathy• Lumbo-Sacral Plexopathy• Vasculitis
    27. 27. Quick Review• Dorsiflexion and Eversion: – Tibialis Anterior: dpn L4-L5 – Extensor Hallucis Longus dpn L4-L5 – Extensor Digitorum Longus dpn L4-L5 – Peroneus Tertius dpn L4-L5• Eversion: (weak plantar flexion) – Peroneus Brevis spn L5-S1 – Peroneus Longus spn L5-S1
    28. 28. Peroneal Neuropathy• Most Common mononeuropathy on the LE – Causes: compression, entrapment, ischemia, direct trauma, Knee dislocation or bicruciate injury, pneumatic compression devices – Ex: rapid weight loss, tight cast or brace, crossing legs, repetitive squatting, sitting on an airplane or positioning during surgery – Both> deep> superficial
    29. 29. Evaluation• Rigorous history and physical• Basic Labs: inflammatory panel etc• Referral for EMG• Safety: Appropriate Prosthetics• ?Imaging: Lumbo-Sacral, Pelvic MRI
    30. 30. Peroneal Neuropathy• Routine LE Assessment – NCS and EMG• NCS – Sensory: sural, superficial peroneal – Motor: peroneal(EDB, TA), Tibial(AHL) – contralateral peroneal motor (EDB, TA) and superficial peroneal sensory – Drop of >20% amplitude in CMAP is abnormal
    31. 31. Fun Fact• The SHBF • only muscle proximal to fibular neck that is innervated by the peroneal nerve, so if peroneal neuropathy at fibular neck the SHBF should be intact
    32. 32. Classic Findings• Reduced peroneal CMAP amplitude side to side• Focal Slowing Across the fibular head• Normal sural sensory, tibial motor• EMG findings of spontaneous activity and/or reinnervation• Normal findings in gastroc, quads, tib post, paraspinals, SHBF
    33. 33. What you want to see!• Associated Nerves are tested – Peroneal motor, tibial motor, super. Per. Sensory, sural sensory• Abnormalities differentiated• Contra-lateral side compared – Same nerves• Appropriate Muscles Sampled – TA,BFSH, BFLH or Semitendinosis, Post. Tib
    34. 34. Case #2 25 y/o male golfer presents to clinic with pain over the inner right ankle andnumbness on the sole of his foot
    35. 35. Differential Diagnosis• Tarsal Tunnel Syndrome• Plantar Fasciitis• L4 Radiculopathy• Ankle Sprain• Diabetic/Metabolic/Toxic Neuropathy
    36. 36. Tibial Nerve: 2 sensory M. & Lat. Calcaneal Sensory 2 Mixed Motor and Sensory M. And Lat. Plantar
    37. 37. Evaluation• Rigorous history and physical• Intervention vs:• Referral for EMG• ?Imaging: Lumbo-Sacral, Pelvic MRI
    38. 38. Tarsal Tunnel Syndrome• Described by Keck in 1962• compression neuropathy of the tibial nerve – Flexor retinaculum• Common Pre-Disposing Factors: – Pes planus with valgus hindfoot – crush injury, stretch injury, fractures, dislocations of the ankle and hindfoot – severe ankle sprains
    39. 39. Tarsal Tunnel Pressure• Trepman et al.: – anatomic space pressure in the tarsal tunnel – Pronated:  32 mmHg – Neutral: 1 mmHg – Inversion of the foot as well as plantarflexion of the ankle reduced the tarsal compartment pressure significantly.
    40. 40. Classic EMG Findings• Prolonged latency or low Amplitude Medial or Lateral Plantar Sensory or mixed Nerve Responses• Prolonged distal Latency of the medial or lateral plantar motor nerves• Decreased amplitude of the above• Spontaneous potentials
    41. 41. What you want to see!• Appropriate nerves tested• Associated Nerves are tested – Sensory: Sural, Saphenous Sensory, Medial and lateral plantar – Motor: Peroneal, tibial• Abnormalities differentiated• Contra-lateral side compared – Same nerves• Appropriate Muscles Sampled – Foot Muscles: ADM, FDM, Abductor hallucis, FDB
    42. 42. Case #3 35 y/o male Police OfficerPresents with numbness and occasional “weird feelings” over the front and side of his thigh
    43. 43. Differential Diagnosis• L2-L4 Radiculopathy• Lateral Femoral Cutaneous Neuropathy• Lumbar Plexopathy – Mass, Hematoma, Compression, Traction, Radiation• Femoral Neuropathy
    44. 44. Purely Sensory: NO Motor Origin: L2-3 via Lumbar plexusThrough the Pelvis Along the lateral border of the psoas muscleUnder the inguinal ligament ≈1cm medial to the ASIS
    45. 45. Meralgia Paresthetica Meros= thigh Algo= Pain• Obesity• Pregnancy• Tight clothing (low rise jeans), leaning against a table for work, uneven bar in gymnastics• Tool belts, military gear, recent weight loss• Diabetic and metabolic neuropathies• Other: masses, hematomas in the retroperitoneal space
    46. 46. EMG• NCS – peroneal and tibial motor (with F wave) – sural sensory, LFCN bilaterally• NEE – L3-4: quadricep – L4-5: tibialis anterior – L5-S1: glut. med. (L5) or max. (S1), tibialis post. or FDL, EDB – S1-2: medial gastroc., abductor hallucis – paraspinal
    47. 47. Of Note• NCS: of the LFCN is technically challenging and many patients are unable to tolerate• NEE: Anticipated to be “normal” but can help rule out “radiculopathy”
    48. 48. Case #465 y/o female recreational swimmer Presents concerned With difficulty climbing stairs and occasional falls because my “knee is buckling”
    49. 49. Differential Diagnosis• L2-L4 Radiculopathy• Femoral Neuropathy• Lumbo-Sacral Plexopathy• Intra-Aricular Knee or Hip Pathology• Poly-Myalgia Rheumatica
    50. 50. You Think• Knee Extension – Quadriceps• Thigh Flexion – Iliopsoas
    51. 51. LEVAN
    52. 52. Femoral Nerve Motor Sensory• Iliacus • Saphenous Nerve• Pectineus• Sartorius• Rectus Femoris• Vastus Lateralis• Vastus Intermedius• Vastus Medialis
    53. 53. Femoral Nerve Neuropathy• Findings: – Weakness in thigh flexion and knee extension – Decreased sensation over anterior thigh and medial leg – Loss of ipsilateral patellar reflex• Causes: – Compression (mass, hematoma), iliac aneurysm, trauma in surgery, femoral line placement,
    54. 54. EMG• NCS – Motor: femoral (rectus femoris), peroneal and tibial (with F wave) – Sensory: sural, saphenous (bilaterally)• NEE – L3-4: quadricep – L4-5: tibialis anterior – L5-S1: glut. med. (L5) or max. (S1), tibialis post. or FDL, EDB – S1-2: medial gastroc., abductor hallucis – paraspinal
    55. 55. What you want to see!• Routine LE assessment• NCS - B femoral motor• NEE - at least 2 quads, iliopsoas, adductor longus, upper lumbar paraspinals
    56. 56. Expected EMG Findings• NCS: – Motor: abnormal rectus femoris CMAP – Sensory: abnormal saphenous findings, with normal sural• NEE: – Abnormal activity in the femoral innervated muscles, normal findings elsewhere
    57. 57. Quick Notes• Femoral Nerve: – Distal or at Inguinal Ligament • quads affected – If both quads and iliopsoas affected must rule out lumbar radiculopathy vs retroperitoneal involvement.
    58. 58. Case #5 21 y/o male lineman footballplayer presents to clinic with complaints ofbeing unable to raise his right foot
    59. 59. Differential Diagnosis• Peroneal Neuropathy• L5 Radiculopathy• Sciatic Neuropathy• Lumbo-Sacral Plexopathy• Vasculitis• Ankle Injury/Intra-articular pathology
    60. 60. Lumbar Innervation• L2-3-4 • L5-S1• Femoral • Tibial – RF, VM, VL, IP, S – Gsc, PT, FDL, FDB• Obturator • Peroneal – G, AL – PL, PB• L4-5 • S1-2• Peroneal • Tibial – TA – So, AH • Sciatic – BFLH (t), BFSH(p), Sm, St
    61. 61. Exam• Weakness – Ankle Dorsiflexion – Ankle Inversion• Decreased Sensation to LT, PP over medial foot• Absent Hamstring reflex on the right• + SLR, XLR, Fem. Stretch Test• TTP of Lumbar Paraspinals
    62. 62. Lumbar radiculopathy• NCS: – Distal motor and sensory often normal in a single- level radiculopathy.• Needle electromyography: – High diagnostic yield. Timing is important, and the study should be performed less than 4-6 months (but >18-21 d) from symptom onset.
    63. 63. Lumbar Radiculopathy• Clinical Findings: – Pure Sensory> Sensorimotor> Pure motor
    64. 64. Expected EMG• NCS: – Sensory: Normal – Motor: Normal, or slightly reduced amplitude – Reflexes: H Reflex: possibly abnormal• NEE: – Abnormal Findings in L5 innervated muscles with normal findings in L2-L4 and S1 myotomes
    65. 65. Wrapping Up• EMG: – “Extension of the physical exam” – Only order if it will alter your management – Order at least 3 weeks after symptoms begin – Remember patient comfort
    66. 66. Personal Opinions• Meet your “neighborhood” EMG’r• Experience an EMG first-hand• Find an EMG’r who is well trained and you trust
    67. 67. Personal Opinions• Send your patients to the same EMG’r once you have done your research and found a good fit• Ask your patients about the experience and respond accordingly• Discuss concerning findings with the EMG’r
    68. 68. Thank You!
    69. 69. Enjoy more powerpoints and educational resources at www.esserhealth.com