Cadaveric Study of Variations in the Course of Lateral Femoral Cutaneous Nerve: Insight to Prevent Injury.

Objective: A recent spurt in incidence of meralgia paresthetica to 0.1-81% due to minimally invasive anterior approach to hip joint has resulted in reinterest in anatomy of lateral femoral cutaneous nerve (LFCN). Familiarity with variations in the course of LFCN will reduce the morbidity associated with orthopedic procedures around the anterior superior iliac spine (ASIS) and inguinal ligament (IL).

Methods: Twenty five adult human formalin embalmed cadavers were dissected. Course and relations of nerve to ASIS, IL and sartorius muscle was noted, distance of nerve from ASIS at IL was measured and statistically analyzed.

Results: Mean distance of LFCN from ASIS at IL was 1.73±1.15 cm. Differences between two sides and sexes was statistically not significant (p=0.51 and p=0.96 respectively). Inferomedial to ASIS, 94% of LFCNs crossed IL with 92% of them present within 4 cm medial to ASIS. Majority of LFCNs (90%) exited pelvis and entered thigh posterior to IL. Out of these nerves 48% were single trunks on entry into thigh, then bifurcated into anterior and posterior branches. Remaining LFCNs bifurcated proximal to IL or at level of IL. Trifurcations were seen in 6% while a rare case of pentafication was observed. In 66% main trunk/branches were present in intermuscular cleft between sartorius muscle and tensor fascia lata.

Conclusions: Care should be exercised by surgeons while dissecting around IL as more than half of nerves are liable to be injured during operative procedures. This would help in better anticipation of problem, acceptance and reducing litigation.