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EMG 101 Empowering Chiropractic

EMG 101 Empowering Chiropractic. Jerrold Simon, DC, DACBN, DACRB, DABDA, DIBE, FICC. Outline. EMG 101 – Empowering Chiropractic J. Simon, DC, DACBN, CCN, DACRB, FACCN, DABDA, FACCRS , DIBE, FICC I . EMG – Introduction II. Common Definitions III . The EDX Consultation

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EMG 101 Empowering Chiropractic

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  1. EMG 101Empowering Chiropractic Jerrold Simon, DC, DACBN, DACRB, DABDA, DIBE, FICC

  2. Outline EMG 101 – Empowering Chiropractic J. Simon, DC, DACBN, CCN, DACRB, FACCN, DABDA, FACCRS, DIBE, FICC I. EMG – Introduction II. Common Definitions III. The EDX Consultation a. Common EDX Findings b. The Median Nerve & Carpal Tunnel Syndrome - Incidence and Cost of CTS - Etiology and Epidemiology of CTS - Electrodiagnosis of CTS

  3. I. Introduction EMG: Historical Perspective and Definitions

  4. EMGHistory • EMG history and development parallels the history and development of electricity • Good EMG history text is Electrodiagnosisand Electromyography by Sidney Licht, MD first published in 1950 • According to Dr. Licht: Inelectrodiagnosis– A current is emitted to a muscle to evoke contraction In electromyography– A current is evoked from a muscle contraction

  5. EMGinWartime • Much of what we know about EMG was learned from peripheral neuropathies incurred during past wars • EMG became an important tool to determine extent of nerve damage

  6. When considering the historical basis of EMG and its development, we need only look to the: • Italians • French • Germans

  7. The EMG Unit

  8. II. EMG Definitions

  9. Conduction Velocity • Speed of propagation of an action potential along a nerve or muscle fiber. The nerve fiber studied (whether motor, sensory, autonomic or mixed) should be specified

  10. Electromyography • Strictly defined; the recording and study of insertion, spontaneous, and voluntary electric activity of muscle. EMG is commonly used to refer to nerve conduction velocity (NCV) studies as well.

  11. F-wave • A compound action potential evoked intermittently from a muscle by a supramaximal electric stimulus to the nerve. Compared with the maximal amplitude M-wave of the same muscle, the F-wave has a smaller amplitude, variable configuration and a longer, more variable latency.

  12. Fasciculation • The random, spontaneous twitching of a group of muscle fibers or a motor unit. This twitch may produce movement of the overlying skin (limb), mucous membrane (tongue), or digits. The electric activity associated with the spontaneous contraction is called the fasciculation potential.

  13. Fibrillation • The electric activity associated with a spontaneously contracting (fibrillating) muscle fiber. It is the action potential of a single muscle fiber. The action potentials may occur spontaneously or after movement of the needle electrode. The potentials usually fire at a constant rate, although a small proportion fire irregularly.

  14. H-Wave • A compound muscle action potential having a consistent latency evoked regularly when present, from a muscle by an electric stimulus to the nerve. It is regularly found only in a limited group of physiologic extensors, particularly the calf muscles and is affiliated with the S-1 nerve.

  15. Latency • Interval between the onset of the stimulus and the onset of the response.

  16. Positive Sharp Wave • A biphasic, positive-negative action potential initiated by needle movement and recurring in a uniform, regular pattern at a rate of 1-50 hertz, the discharge frequency may decrease slightly just before cessation of discharge.

  17. Threshold • The level at which a clear and abrupt transition occurs from one state to another. The term is generally used to refer to the voltage level at which an action potential is initiated in a single axon or a group of axons.

  18. III. The EDX Consultation

  19. TheEDXMedicineConsultation • EDX consultations are indicated for investigation of diverse disorders of the PNS & CNS, neuromuscular junction (NMJ) and muscle • EDX studies help to evaluate symptoms such as weakness, numbness, tingling, pain, fatigue, cramping, stiffness and abnormal sensations

  20. The EDX Consultation (cont’d) • EDX studies are an extension of the clinical and neurological exam • The EDX consult should begin with a history and brief physical exam focused on the problem which prompted the referral • The EDX study should attempt to either prove or disprove the referring doctor’s working diagnosis or clinical hypothesis

  21. The EDX Consultation (cont’d) • Unlike laboratory tests, the EDX exam must be specifically designed by a clinically knowledgeable physician for each individual set of clinical circumstances, then altered and modifiedaccording to findings which evolve during the examination • This requires that the EDX physician have extensive knowledge of clinical medicine, anatomy, physiology and bioelectronics

  22. The EDX Consultation (cont’d) • EDX studies provide diagnostic accuracy and sensitivity not otherwise possible • EDX studies can help to document the presence of one or more areas of nerve damage and place in perspective the anatomic abnormalities noted on imaging studies • EDX studies are particularly helpful when the clinical exam is limited by poor patient cooperation related to pain, brain or spinal cord pathology or psychosomatic factors

  23. The EDX Consultation (cont’d) • EDX studies can define and differentiate the pathophysiology and distribution of disease processes involving muscle, the NMJ, nerves, plexi, roots and CNS • NCVs & EMGs can help to differentiate primarily axonal pathology from demyelination of peripheral nerves and can help distinguish between necrotic and nonnecrotic myopathies

  24. The Median Nerve & Carpal Tunnel Syndrome • Anatomy of the Median N. • Incidence and Cost of CTS • Etiology & Epidemiology of CTS • Physical Diagnosis of CTS • Electrodiagnosis of CTS

  25. Clinical Description of CTS by Kremer,Gilliatt, Golding & Wilson in 1953 • “The usual complaint [of CTS] is of attacks of painful tingling in one or both hands at night, sufficient to wake the sufferer after a few hours of sleep. The pain and paraesthesiae are usually described as burning or agonizing and a deep-seated ache may spread up the forearm to the elbow. The ache is severest on the inner aspect of the forearm and more rarely may be seen in the shoulder muscles.”

  26. AnatomyoftheMedianNerve • The Median N. is formed from the nerve roots C-5 to T-1 • The C-5, C-6 & C-7 roots contribute to the lateral cord of the brachial plexus • The C-8 & T-1 roots contribute to the medial cord of the brachial plexus • Components from both the medial & lateral cords join to form the Median N.

  27. Median N. Cutaneous Sensory Patterns • Mapped by careful study of patients with Median, Ulnar or Radial N. injuries using a camel hair brush to find the areas of sensory loss • Typically, the Median digital nerves supply the palmar surfaces of the thumb, index, middle and lateral half of the ring fingers • On the dorsal surface, the Median digital nerves supply the dorsal tips of the index, middle and lateral side of the ring finger

  28. The Carpal Tunnel • The tunnel itself is formed dorsally and laterally by the eight carpal bones and volarly by the transverse carpal ligament (flexor retinaculum) which ranges between 1 – 2 mm in thickness • The transverse carpal ligament attaches to the hook of the hamate and the pisiform on the ulnar side of the hand

  29. Incidence and Cost of CTS • Carpal Tunnel Syndrome is the most common, best defined and most carefully studied entrapment neuropathy* • In 1998, a survey of California physicians estimated that 515 of 100,000 patients sought medical attention for CTS • In the Netherlands, a prevalence of 220 per 100,000 has been reported *EntrapmentNeuropathies David Dawson, et al 1999

  30. Cost of Carpal Tunnel Syndrome • There are an estimated 400,000 cases of CTS diagnosed each year in the U.S. • Approximately 260,000 carpal tunnel surgeries are performed each year in the United States • The estimated yearly medical cost of treating CTS is in excess of $5 Billion* *Electromyogr.Clin.Neurophysiol.,2004,44,379 -383.

  31. CTS Predictive Factors • CTS is 1.8 times more prevalent in whitesthan in nonwhites • CTS is 1.7 times more prevalent in females than in males • Certain occupations have a greater predilection for their workers developing CTS including: construction workers (esp. jack hammer operators), typists, key punch operators, garment workers, tailors, painters and stenographers* *JACA 2004, Vol 41, No 8

  32. “Carpal Tunnel Syndrome”Definition • Carpal Tunnel Syndrome – is a constellation of symptoms and signs due to median nerve compression in the carpal tunnel

  33. Activities that Cause CTS* • Sustained wrist or palmar pressure • Prolonged wrist extension or flexion • Repetitive hand or wrist use • Work with vibration tools - jack hammer • Hand use in the cold * Hagberg, Morgenstern & Kelsh 1992

  34. Predetermining Factors in CTS* The following five factors make a worker vulnerable to CTS: • Posture • Repetition • Temperature Extremes • Vibration • Force *JACA 2004, Vol 41, No 8

  35. The Wieslander Study - 1989 Wieslander, et al did a case-control study using hospital records to match patients who had undergone carpal tunnel surgery to randomly chosen controls. The study concluded that those patients who underwent carpal tunnel surgery were morelikely to use:vibrating hand tools, repetitive wrist movements & heavy lifting maneuvers

  36. NIOSH Statement - 1997 The National Institute for Occupational Safety and Health (NIOSH) review of epidemiological studies on occupational carpal tunnel syndrome concluded that“there is evidence of positive associations between highly repetitive work, forceful work, or exposure to vibration and the development of CTS”

  37. Physical Diagnosis of CTS • An accurate diagnosis of carpal tunnel syndrome dictates the need for a thoroughphysical exam with focal attention to the upper extremity, an extensive history with particular attention to the patient’s vocation and an upper extremity NCV/EMG exam

  38. Symptoms of CTS • Hand Numbness and Paresthesias • Numbness Relieved by Shaking of Hand • Hand Pain During Prolonged Gripping • Nocturnal Hand Numbness Affecting Quality of Sleep • Tingling or Burning Pain in the Digits • Finger Blanching and Dry Palms

  39. CTS Physical Exam Provocative Tests* CTS Provocative Tests which are used to either elicit or relieve symptoms include: • Phalen’s Sign • Tinel’s Sign • Median Nerve Compression Test • Hand Elevation Test • Flick Sign • Relief Maneuver *CarpalTunnelSyndrome Rosenbaum & Ochoa 2002

  40. Electrodiagnosis of CTS • An accurate diagnosis of carpal tunnel syndrome dictates the need for a thorough physical exam with focal attention to the upper extremity, an extensive history with particular attention to the patient’s vocationand an upper extremity NCV/EMG exam

  41. Nerve Conduction Velocity Test- NCV • The Median Nerve NCV test is composed of both motor and sensorycomponents • The NCVMotor Exam utilizes the abductor pollicis brevis muscle (proximal thumb) as an indicator muscle • The first stimulation is performed 8 cm proximal from the apbmuscle in the midline of the forearm along the Median nerve • Average latency value is < 4.2 ms

  42. Median NCV Test - sensory • The NCV Sensory Examutilizes ring electrodes around the index finger • The first stimulation is performed 14 cm proximal to the closest ring electrode with the stimulation also in the midline of the forearm along the Median nerve • Average latency value is < 3.5 ms

  43. Median Nerve EMG Test • When utilizing EMG to test for carpal tunnel syndrome, most often the abductor pollicisbrevismuscle or the lumbricals are needled • The electrodiagnosis of CTSis made when the Median motor NCV T.F. latency > 4.2 ms and the sensory NCV T.F. latency > 3.5 ms. In addition, the EMG may reveal acute neuropathic denervation. Remember, the definitive diagnosis of CTS is multifactorally based.

  44. Carpal Tunnel Syndrome Conservative Therapies • Carpal Tunnel Volar “Neutral” Wrist Splint • Avoidance of Repetitive Wrist Movements • Ergonomic Reorganization of Workplace • Wristiciser Rehabilitation w/ B-6 vitamins • Local Corticosteroid Injection (Palmaris L.) • Ultra-Sound/Cold Laser Therapy • Wrist Mobilization/Manipulation

  45. The End

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