Why are posterior tibial nerve somatosensory evoked potentials (SEPs) preferred in the lower limb?

Updated: Feb 26, 2019
  • Author: Sombat Muengtaweepongsa, MD, MSc; Chief Editor: Selim R Benbadis, MD  more...
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Answer

Answer

In the lower limb, posterior tibial SEPs are generally preferred because of the following:

  • In clinical diagnostic use, they are larger and display less intrasubject variability.

  • In intraoperative settings, they produce less patient movement.

  • In intraoperative settings, electrodes at the ankle are more accessible, and thus more easily replaced should they malfunction, than those at the knee.

  • The peripheral nerve compound action potential (CAP) can be recorded at the popliteal fossa and can be used to determine whether the nerve is being adequately stimulated. This is crucial when the rostral SEPs deteriorate during intraoperative monitoring, to indicate whether the SEP changes are caused by spinal cord compromise or by technical problems with nerve stimulation.


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