2023 Workshop Handout Bundle-Evaluation of Proximal Upper and Lower Limb Mononeuropathies

Evaluation of Proximal Upper and Lower Limb Mononeuropathies

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Dr. William Litchy conducted a workshop at the 2023 AANEM Annual Meeting, focusing on electrodiagnostic evaluation techniques for proximal upper and lower limb mononeuropathies. Mononeuropathies, localized nerve damage affecting a single nerve, and plexopathies, involving nerve plexuses, are common both in upper and lower limbs. Despite a higher frequency in distal nerves, proximal nerves are equally significant for nerve damage assessments.<br /><br />The workshop aimed to provide hands-on training for conducting nerve conduction studies, a critical diagnostic tool in neurophysiology. These studies are key in identifying nerve dysfunction by measuring electrical activities in muscles and nerves. The techniques demonstrated are those most frequently used in Mayo Clinic's laboratory, selected for their relevance, reliability, reproducibility, available reference data, ease, and comfort.<br /><br />General principles for carrying out these studies include ensuring functional equipment, preparing the patient by cleaning the skin and maintaining an adequate limb temperature, and correctly placing the electrodes. Specific methodologies are offered for different nerves, notably the Accessory, Axillary, Musculocutaneous, Phrenic, Suprascapular, Lateral Antebrachial Cutaneous, Medial Antebrachial Cutaneous, Femoral, and Lateral Femoral Cutaneous Nerves.<br /><br />Each section details the techniques including electrode placement, stimulation procedures, measurement of compound muscle action potential (CMAP) and sensory nerve action potential (SNAP), as well as troubleshooting common issues like shock artifact, movement artifact, and incorrect measurements. Moreover, the workshop emphasizes the importance of side-to-side comparisons for evaluating mononeuropathies and provides specific measurement techniques and normal reference values.<br /><br />The detailed procedural aspects include handling potential difficulties, ensuring patient comfort, and obtaining accurate measurements. Reference texts for further reading and study include works by Kimura, Liveson, Preston & Shapiro, Rubin & Daube, and Stewart. Advanced techniques like the usage of ultrasound to locate nerves and needle stimulation for deep nerves are also discussed in the context of achieving maximal, reliable responses for accurate diagnostics.

Keywords

electrodiagnostic evaluation

mononeuropathies

proximal nerves

nerve conduction studies

ncs

neurophysiology

Mayo Clinic

electrode placement

compound muscle action potential

sensory nerve action potential

ultrasound diagnostics

nerve conduction studies

nerve conduction study

ncs