Proximity of LFCN to ASIS Plays a Role in the Development of Meralgia Paresthetica

University of Wisconsin - Madison

Garret Greeneway, Bo P Lear

Meralgia paresthetica (MP) results from lateral femoral cutaneous nerve (LFCN) compression at the groin. Patients present with burning sensation, allodynia, and paresthesia in the anterolateral thigh. Surgical decompression has been performed in treating MP patients that fail conservative therapy. A high rate of symptom recurrence is observed with decompression alone. We routinely perform transposition of the LFCN in our institution, since 2013. The procedure entails decompression of the LFCN canal by releasing fascial planes superficial and deep to the nerve, together with the septum medial to sartorius. This allows medial mobilization of the nerve for about 2 cm away from the anterior superior iliac spine (ASIS). Our results have been very good. We observed an LFCN course in close relationship to the ASIS in our surgical patients. The objective of this study was to compare the distance of the LFCN to the ASIS in our surgical cohort of MP patients with a cadaver control cohort. A total of 35 patients were treated surgically for MP between 2017 and 2023. There were 14 females and 21 males. The mean patient age was 51.6 years old. A total of 38 extremities were dissected in 20 cadavers. We prospectively collected data from 35 patients surgically treated for MP. Distance from LFCN to ASIS was measured intraoperatively on every patient. Similar data was collected from 38 cadaveric dissections. 43% of the LFCN analyzed were found to be on or lateral (negative value) to the ASIS in the patient cohort compared to only 8% in the cadaver (p<0.0001). A groove was noted in the bone (suprailiac groove) in 20 patients (57%), vs one in the cadaver (2.6%) (p<0.0001). This study supports the concept of there being a neural-bony conflict in patients with MP and calls for the necessity of transposition rather than decompression alone.