New method to perform medial plantar proper digital nerve conduction studies

Area of Science:

• Neurophysiology
• Podiatric Medicine
• Nerve Conduction Studies

Background:

• The medial plantar proper digital nerve (MPPDN) is a critical sensory branch in the foot.
• Accurate assessment of MPPDN function is essential for diagnosing peripheral neuropathies.
• Joplin's neuroma involves the MPPDN, necessitating reliable electrodiagnostic tools.

Purpose of the Study:

• To describe and validate a novel technique for recording sensory nerve action potentials (SNAP) from the MPPDN.
• To establish normative reference values for antidromic MPPDN SNAP parameters in healthy individuals.
• To assess the clinical utility of this technique in evaluating MPPDN involvement.

Main Methods:

• Antidromic sensory nerve action potential (SNAP) recordings were obtained from the MPPDN in 118 healthy volunteers.
• Surface electrodes were placed on the medial aspect of the first metatarsal head of the great toe.
• Electrical stimulation was applied at 40% of the heel-to-great-toe reference line.

Main Results:

• The stimulation site was consistently located at 8.7 ± 1.2 cm from the recording electrodes.
• Reliable MPPDN responses were achieved in 109 out of 118 limbs (92.4%).
• Mean SNAP amplitude was 16.1 ± 6.7 microV, with a range of 6.4 to 34.4 microV.

Conclusions:

• Antidromic stimulation of the MPPDN between 8-10 cm from the recording site yields dependable SNAP responses.
• This technique provides a reliable method for assessing MPPDN function.
• The described method is anticipated to be beneficial for evaluating MPPDN pathologies, including Joplin's neuroma.