2024 Workshop Handout Bundle-W111AS Unusual Sensory Conduction Studies Sridhara

W111AS Unusual Sensory Conduction Studies Sridhara
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The document outlines the materials and methods presented by Dr. Channarayapatna R. Sridhara during a workshop at the 2024 AANEM Annual Meeting. <br /><br />### Objectives:<br />1. Understand the anatomy of sensory nerves in the lower limbs.<br />2. Integrate sensory nerve evaluation into electrodiagnostic studies.<br />3. Perform sensory conduction studies on lesser-known nerves, such as superficial fibular, sural, saphenous, posterior femoral cutaneous, and lateral femoral cutaneous nerves.<br />4. Minimize technical noise to optimize results.<br />5. Interpret sensory findings within the context of a full electrodiagnostic study for diagnosis, prognosis, and management.<br /><br />### Introduction:<br />Since 1956, sensory conduction studies have been integral to electrodiagnostic studies. Over the years, advancements in technology have improved the ease and accuracy of these studies. Sensory conduction studies are particularly sensitive to detecting neuropathies affecting sensory fibers and can often reveal abnormalities before motor fibers are affected.<br /><br />### Pathological Features:<br />- **Mononeuropathies** can affect only sensory fibers (e.g., radial or superficial peroneal neuropathies).<br />- **Generalized sensory neuropathies** can be caused by factors such as cancer or medications.<br />- **Segmental demyelinating lesions** may initially affect sensory fibers.<br />- Sensory nerves are generally more sensitive to axon loss or conduction block lesions, and robust sensory responses in the presence of sensory loss help distinguish between pre- and post-ganglionic lesions.<br /><br />### Technical Challenges:<br />Recording sensory responses can be technically challenging due to factors like local edema, obesity, and coarse skin. Bilateral comparative studies can help determine if a pathology is focal or generalized.<br /><br />### Tips for Sensory Conduction Studies:<br />1. Use minimal pressure with the stimulator.<br />2. Keep a hand over the ground electrode.<br />3. Avoid crossing wires.<br />4. Properly use electrode gel and clean/abrade skin to reduce artifact.<br /><br />### Needle Stimulation Technique:<br />Utilize a monopolar needle for stimulation, adjusting depth and stimulation intensity gradually to find an optimal response. This method benefits patients with obesity, edema, or deeply situated nerves by requiring lower stimulation currents.<br /><br />### Sensory Nerve Conduction Techniques:<br />Detailed procedural guidelines are provided for testing specific nerves like the medial dorsal cutaneous branch of the superficial fibular, sural, saphenous, posterior femoral cutaneous, and lateral femoral cutaneous nerves. These include specific anatomical landmarks and positioning advice to optimize the accuracy and sensitivity of the conduction studies.<br /><br />### Reference Values:<br />Includes age-adjusted normative data for SNAP amplitude, DSL, and CV for each nerve, highlighting differences across age groups.<br /><br />### References:<br />The document cites numerous studies that have contributed to the development and refinement of sensory nerve conduction studies.<br /><br />In summary, the workshop emphasized the importance of specific techniques and technical nuances in conducting accurate and informative sensory nerve conduction studies in the lower limbs, with a focus on lesser-studied but clinically significant nerves.
Keywords
sensory nerves
electrodiagnostic studies
sensory conduction
neuropathies
technical challenges
needle stimulation
lower limbs
superficial fibular nerve
sural nerve
saphenous nerve