Anatomical Variations of the Iliohypogastric Nerve: A Systematic Review of the Literature

Abstract

Several anatomical variations of the iliohypogastric nerve branches have been observed in earlier studies. Knowledge of these variations is useful for the improvement of peripheral nerve blocks and avoidance of iatrogenic nerve injuries during surgeries. The purpose of this study was to perform a systematic review of the literature about the anatomical topography and variations of the iliohypogastric nerve. An extensive search on PubMed, Scopus, and Web of Science electronic databases was conducted by the first author in November 2021, based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Anatomical or cadaveric studies about the origin, the course, and the distribution of the iliohypogastric nerve were included in this review. Thirty cadaveric studies were included for qualitative analysis. Several anatomical variations of the iliohypogastric nerve were depicted including its general properties, its origin, its branching patterns, its course, its relation to anatomical landmarks, and its termination. Among them, the absence of the iliohypogastric nerve ranged from 0 to 34%, its origin from L1 ranged from 62.5 to 96.5%, and its isolated emergence from psoas major ranged from 47 to 94.5%. Numerous anatomical variations of the iliohypogastric nerve exist but are not commonly cited in classic anatomical textbooks. The branches of the iliohypogastric nerve may be damaged during spinal anesthesia and surgical procedures in the lower abdominal region. Therefore, a better understanding of the regional anatomy and its variations is of vital importance for the prevention of iliohypogastric nerve injuries.

Prevalence of the aberrant mode of double ilioinguinal nerve

“…These nerves are indicated for anesthesia in inguinal surgery, especially in the pediatric field (Schoor et al, 2005). As part of the lumbar plexus, the IIN is the 1 st nerve that arises from L1 and occasionally in conjunction with T12 (Manolakos et al, 2022). Along with the IHGN, they emerge from the lateral edge of the psoas, passing ventral to the quadratus lumborum, posterior to the renal fossa, through renal fat and posterior to the inferior end of the kidney (Mirjalili, 2020;Manolakos et al, 2022).…”