Electrodiagnostic Evaluation of Meralgia Paresthetica

Abstract

Background: We aimed to determine the utility of different electrodiagnostic (EDx) methods in diagnosing meralgia paresthetica (MP). Methods: Twenty-nine MP patients and 26 controls were included. Sensory nerve action potential (SNAP) and somatosensory evoked potential (SEP) of the lateral femoral cutaneous nerve (LFCN) and tibial SEPs were measured bilaterally. Results: At least one LFCN SNAP was unobtainable in 18 patients (62%) and two controls (8%). In all remaining 11 patients, SNAPs were abnormal at least unilaterally. By contrast, LFCN SEPs were recorded bilaterally in all subjects and were abnormal in 16 patients (sensitivity 48%). Patients’ tibial SEP latency was significantly larger than that of controls (p < 0.001). Conclusions: LFCN NCSs are superior to SEP in the evaluation of MP. However, SEP studies may be useful in old (>60 years) and obese subjects with unobtainable LFCN SNAP. Longer tibial SEP points to subclinical neuropathy in MP patients predisposed to LFCN entrapment.