To verify the utility of the lateral femoral cutaneous nerve (LFCN) ultrasound-guided conduction technique compared to that of the conventional nerve conduction technique.
Fifty-eight legs of 29 healthy participants (18 males and 11 females; mean age, 42.7±14.9 years) were recruited. The conventional technique was performed bilaterally. The LFCN was localized by ultrasound. Cross-sectional area (CSA) of the LFCN and the distance between the anterior superior iliac spine (ASIS) and the LFCN was measured. The nerve conduction study was repeated with the corrected cathode location. Sensory nerve action potential (SNAP) amplitudes of the LFCN were recorded and compared between the ultrasound-guided and conventional techniques.
Mean body mass index of the participants was 23.7±3.5 kg/m2, CSA was 4.2±1.9 mm2, and the distance between the ASIS and LFCN was 5.6±1.7 mm. The mean amplitude values were 6.07±0.52 µV and 6.66±0.54 µV using the conventional and ultrasound-guided techniques, respectively. The SNAP amplitude of the LFCN using the ultrasound-guided technique was significantly larger than that recorded using the conventional technique.
Correcting the stimulation position using the ultrasound-guided technique helped obtain increased SNAP amplitude.
Citations
Objective: The purpose of this study was to determine the reliability and usefulness of the lateral femoral cutaneous nerve conduction study by comparing the modified Ma's method (method I) with the method proposed by Spevak and Prevec (method II) and to develop a standard value of the Korean normal adult by the method II.
Method: Twenty-nine healthy adults were examined for the lateral femoral cutaneous nerve conduction by both methods bilaterally. The nerve was stimulated 1 cm medial to anterior superior iliac spine (ASIS) in the method I and 8 cm distal to ASIS in the method II. The sensory nerve action potential was recorded with 8 cm long strip electrodes placed on the thigh 17 cm distal to ASIS in the method I and 33 cm distal to ASIS in the method II.
Results: 1) Among 58 extremities, a sensory nerve action potential was detected in 52 extremities (89.7%) by the method I and in 57 extremities (98.3%) by the method II without a significant difference between both methods. 2) The mean distal latency was 3.41 msec by the method I and 4.56 msec by the method II. 3) The mean amplitude was 7.24 ㄍV by the method I and 6.63 ㄍV by the method II without a significant difference between both methods. 4) The mean conduction velocity was 50.9 m/sec by the method I and 55.2 m/sec by the method II without a significant difference between both methods.
Conclusion: According to the study, both methods are compatible and reliable for the examination of lateral femoral cutaneous nerve except for a significant difference in a mean conduction velocity.