Anatomical variations of the iliohypogastric- and ilioinguinal nerves: clinical consideration within a South African population

Inguinal hernias are a common occurrence in both infants and adults. Several surgical procedures to repair these hernias have been introduced, with varying success rates. Decreasing the rate of complication incidence requires an absolute understanding of the anatomical structures involved. A literature review indicated that surgeons favor using the Lichtenstein tension-free method. This study describes the anatomy of the iliohypogastric and ilioinguinal nerves clearly and accurately for application in the successful performance of the Lichtenstein tension-free inguinal hernia repair within a South African population. Together with an extensive literature search, a bilateral dissection was conducted to expose the spinal nerve of the iliohypogastric and ilioinguinal nerves in a sample that included 105 formalin-fixed adult cadavers. The anatomy of the iliohypogastric and ilioinguinal nerves aligned with existing descriptions in anatomical textbooks and literature. The L1 spinal nerve was observed predominantly bifurcating into the iliohypogastric and ilioinguinal nerves within the transversus abdominis muscle before coursing towards the anterior superior iliac spine. The distances of the iliohypogastric and ilioinguinal nerves to the anterior superior iliac spine lie within the recommended 30-40 mm muscle flap described for the Lichtenstein tension-free repair to visualize the nerves. This study reiterates the safety of an iliohypogastric and ilioinguinal nerve block procedure, which is recommended for inguinal hernia repairs within a South African population. It is important to note the variability observed in the study for safe performance and successful early postoperative pain management using the ilioinguinal and iliohypogastric nerve blocks.