Proximal and segmental motor nerve conduction in the sciatic nerve produced by percutaneous high voltage electrical stimulation.

Percutaneous high voltage electrical stimulation was applied to the proximal sciatic nerve at the hip in 18 normal subjects to evaluate motor conduction in the proximal sciatic nerve, and short-segment stimulation of the sciatic and posterior tibial nerves was given in 6 normal subjects. Compound muscle action potentials (CMAPs) were recorded from the abductor hallucis (AH) and extensor digitorum brevis (EDB) muscles. Supramaximal stimulation was easily obtained at the proximal sciatic nerve and all the sites in the short-segment stimulation. The motor nerve conduction velocity of the sciatic nerve between the hip and the popliteal fossa was 49.2 +/- 4.24 m/sec in the tibial division and 54.1 +/- 6.48 m/sec in the peroneal division. The respective peak-to-peak amplitude and negative-peak areas of the CMAPs at the hip were reduced to 86.8 +/- 5.65% and 97.3 +/- 5.36% for the tibial division, and 93.4 +/- 7.06% and 96.8 +/- 5.09% for the peroneal division as compared to the values for the popliteal fossa. The negative-peak duration of the CMAPs at the hip point were increased to 109.2 +/- 7.2% for the tibial nerve and 107.1 +/- 5.68% for the peroneal nerve as compared with the duration at the popliteal fossa. This method is non-invasive and useful for evaluating motor nerve conduction in the lower limb.