2023 Workshop Handout Bundle-NCS of the Foot

NCS of the Foot

Pdf Summary

The document provides extensive information on entrapment neuropathies in the lower extremity, highlighting the most common sites and mechanisms of peripheral nerve entrapment, along with methods for electrodiagnostic evaluation. Entrapment neuropathy is described as a focal mononeuropathy caused by mechanical impingement of nerves passing through fibrous or osseofibrous tunnels or over fibrous or muscular bands, leading to symptoms influenced by various factors like age and systemic diseases. The primary pathology involves focal segmental demyelination and can lead to axonal degeneration if severe. Nerve conduction studies (NCSs) are crucial in diagnosing entrapment neuropathies by detecting focal demyelination and segmental slowing in nerve conduction velocity (NCV).<br /><br />Key focus areas include entrapment neuropathies of the peroneal nerve, with the common peroneal nerve being particularly susceptible to injury at the fibular head. Mechanisms of injury include acute compression, traction, laceration, and compression by osseofibrous tunnels or trauma. Techniques for electrodiagnostic evaluation include recording motor conduction from the extensor digitorum brevis (EDB) and anterior tibialis, with stimulation above and below the fibular head. Findings may show conduction block, reduced amplitude, or axonal loss depending on the extent and nature of the injury.<br /><br />The document also discusses the posterior tibial nerve and its branches, focusing on conditions like tarsal tunnel syndrome (TTS) and various isolated neuropathies affecting the medial and lateral plantar nerves. Detailed methods for conducting motor and sensory NCSs for these nerves are provided, emphasizing setup, stimulation, and measurement techniques.<br /><br />In addition, the document includes a comparative study of four different techniques for conducting superficial fibular sensory nerve (SFSN) conduction studies, highlighting the Spartan technique developed at Michigan State University. The analysis compares distal latency, amplitude, and stimulation required to obtain responses, concluding that while statistical differences exist among techniques, they all reliably detect SFSN action potentials in 95% of individuals.<br /><br />Overall, the document serves as a comprehensive guide for diagnosing and evaluating entrapment neuropathies in the lower extremity using various electrodiagnostic techniques.

Keywords

entrapment neuropathies

lower extremity

peripheral nerve

electrodiagnostic evaluation

nerve conduction studies

ncs

common peroneal nerve

tarsal tunnel syndrome

posterior tibial nerve

motor conduction

superficial fibular sensory nerve

nerve conduction studies

nerve conduction study

ncs