Normal anatomy and variations of the lateral femoral cutaneous nerve in relation to the iliac crest: implications for anterior iliac crest bone grafts (726.10)

Abstract

Anterior iliac crest bone grafting (AICBG) remains the gold standard for reconstructive procedures in orthopedic and oral‐maxillofacial surgeries. It has been estimated that 10% of patients undergoing AICBG are at risk of injury to their lateral femoral cutaneous nerve (LFCN). Injury to this nerve can result in numbness, burning, itching or pain sensations over the lateral aspect of the thigh, known as meralgia paresthetica. The course of the LFCN within the greater pelvis cannot be seen with imaging technologies. The objective of this study is to elucidate the 3D course and variability of the LFCN as it emerges from the psoas major muscle to the anterior superior iliac spine (ASIS). Using 25 embalmed cadavers, the length and depth of the LFCN is measured from the ASIS to 7 cm posterior to the ASIS at 1 cm intervals. Preliminary results (n=10 sides) show these measurements are highly variable between cadavers and that there are three ways the nerve courses: convex, concave or straight course. The first three dimensional danger‐zone of the LFCN relative to the iliac crest will be established and incorporated onto a 3D illustration of the pelvic bone using Amira software. A predictive model will be determined to approximate the location of the LFCN with respect to age, sex, height, bone width, and ASIS‐ASIS distance. A better understanding of the course of the LFCN is important to minimize graft site morbidity.