Preoperative Ultrasound in Patients with Meralgia Paresthetica to Detect Anatomical Variations in the Course of the Lateral Femoral Cutaneous Nerve

Abstract

Sometimes during surgery for meralgia paresthetica, it can be difficult to find the lateral femoral cutaneous nerve (LFCN). The aims of this study were to study the prevalence of different anatomical variations in patients, compare preoperative ultrasound (US) data with intraoperative findings, and investigate the effect of type of anatomical variation on duration of surgery and success rate of localizing the LFCN. Fifty-four consecutive patients with idiopathic meralgia paresthetica who underwent either a neurolysis or neurectomy procedure were included. All patients preoperatively underwent US of the LFCN. Anatomical variations were categorized into type A, B, C, D, and E using the classification of Aszmann and Dellon. The cross-sectional area of the LFCN at the inguinal ligament and the distance of the LFCN to the anterior superior iliac spine were noted. Correlations with intraoperative findings were investigated, as well as the effect on duration of surgery and success rate of finding the LFCN. Clinical outcome was assessed using the Likert scale. The most frequent anatomical variant was type B (79%), followed by type C (9%), D (5%), and E (7%). No type A was encountered. Correlation between preoperative US and intraoperative findings was 100%. During surgery, the LFCN could be identified in all cases. Duration of surgery did not significantly vary for the different anatomical variants. Preoperative US is reliable in detecting anatomical variations of LFCN. This information can be very helpful in identifying the LFCN more frequently and easily during surgery, especially in more medial variants.