tunnel syndrome nerve conduction study腕管綜合征的神經(jīng)傳導(dǎo)研究課件

CARPAL TUNNEL SYNDROME Nerve Conduction Study Katie Doney .au Motor Pathways Ventral Horn CNS Motor Neuron Muscle Motor Pathways Possible places of dysfunction 1.CNS 1.EEG Electroencephalography 2.PET Positron Emission Tomography 3.fMRI Functional Magnetic Resonance Imaging Motor Pathways Possible places of dysfunction 2. Muscle Needle EMG Electromyography 1.CNS 1.EEG Electroencephalography 2.PET Positron Emission Tomography 3.fMRI Functional Magnetic Resonance Imaging Motor Pathways Possible places of dysfunction 2. Muscle Needle EMG Electromyography 1.CNS 1.EEG Electroencephalography 2.PET Positron Emission Tomography 3.fMRI Functional Magnetic Resonance Imaging 3. Peripheral Nerve Nerve conduction study Peripheral Nerve Made up of: - Sensory nerves - Motor nerves - Myelin - Glial cells MEDIAN ULNAR Median Nerve Pathology in Carpal Tunnel Syndrome Compression of the median nerve results in DemyelinationAxonal degeneration Decreased blood supply These manifest as: - Numbness - Pain - Parasthesiae - Weakness - Problems with fine manipulative skills Nerve Conduction Study Stimulate nerve and record outcome. 2 main types 1. Motor (record compound muscle action potential) 2. Sensory (record compound sensory action potential) -Orthodromic (stimulate at finger, record on elbow/wrist) -Antidromic (stimulate at elbow/wrist, record on finger) -Radial-median (stimulate at wrist, record on thumb) -Palmar (stimulate at palm, record on elbow/wrist) Most sensitive Least sensitive Changes to CMAP in Carpal Tunnel Syndrome -Latency: Normal 50 m/s Other sources of error stimulus position - estimation of nerve course - latency measurement Problems with comparing features to normal values Features change with Temperature Age Age 2080 Latency Age CV Solution: Repeat measurements on ulnar nerve as a control. This also gives additional evidence to rule out generalised neuropathy. Compound Antidromic Sensory Action Potential Setup: - stimulate at wrist/elbow and record at finger - gain set higher - signal very small so average random noise Normal values: - Latency 50 m/s - Amplitude 15 mV - Latency 54 m/s - Amplitude 10 mV MEDIAN SENSORY (ANTIDROMIC)ULNAR SENSORY (ANTIDROMIC) An example: Right Antidromic Ulnar Normal: -Lat 10 uV . Ulnar OK not generalised neuropathy An example: Right Antidromic MedianNormal: -Lat 15 uV -CV 50 m/s . In median nerve, evidence of demyelination and axonal degeneration between wrist and finger, but not between wrist and elbow. Suggestive of carpal tunnel syndrome. An example: Right Thenar Median Normal: - Lat 50 m/s . Motor portion of median is OK. Mild to moderate carpal tunnel syndrome. Take home message! In carpal tunnel syndrome there will be a longer latency between the wrist and the finger/thenar eminence but NO