Effect of superficial peroneal nerve fascial penetration site on nerve conduction studies

Using nerve conduction studies (NCS) and ultrasonography, we sought to determine the stimulation site that corresponds to the site at which the superficial peroneal nerve (SPN) penetrates the fascia and yields the most accurate NCS results. NCS parameters of the SPN sensory nerve action potential (SNAP) were recorded from 37 legs at 14, 12, 9, 7, and 5 cm (S1, S2, S3, S4, and S5, respectively) proximal to the recording electrode, and analyzed by one-way analysis of variance. SPN penetration sites were visualized by ultrasonography. The mean SNAP amplitude/area (17.2 +/- 6.7 microV/9.6 +/- 4.6 microV/ms) at S3-S5 differed significantly from that at S1-S2 (11.6 +/- 4.7 microV/9.2 +/- 4.4 microV/ms) (F = 10.2, P < 0.001; F = 5.09, P = 0.0007). Ultrasonography showed that the SPN became subcutaneous between S3 and S4. Clinical application of these results should help in obtaining more accurate data during electrodiagnostic studies of conditions that involve the SPN.