Variability in conduction of the lateral femoral cutaneous nerve

The purpose of this study was to establish a reliable technique for assessing conduction in the lateral femoral cutaneous nerve (LFCN), bearing in mind its anatomical variation. Based on our anatomical study, normative values were obtained in 40 healthy nerves. The optimal stimulation site was located 1 cm or more medial to the anterior superior iliac spine (ASIS) in 93% of cases and over the ASIS in 7%. Sensory nerve action potentials (SNAPs) were recorded simultaneously along an imaginary line between the ASIS and the lateral border of the patella and 2 cm medial to this line. Side-to-side variability in amplitude was 31% for the recording from the line and 30% for the medial recording. The variability significantly decreased to 16% when the higher value of each side was compared. Therefore, the measurement of higher amplitude recorded at two different sites may minimize interside variability and improve the diagnostic utility of the LFCN conduction study.