Unique vascular patterns of the internal iliac artery and its clinical import in pelvic surgery

Abstract Introduction With the rising incidence in global maternal mortality caused by obstetric hemorrhage, ligation of the internal iliac artery has emerged as a significant procedure in these patients due to its role as the major arterial source to the pelvic region. However, the internal iliac arterial tree often exhibits variation in its branching pattern. Hence, there is an increasing need to map the anomalous internal iliac arterial tree, the aim upon which this study was based. Materials and methods The branching pattern of the IIa in ten fetal and ten adult cadaveric specimens (n = 40 pelvic sides) was bilaterally investigated through micro- and macroscopic dissection of the pelvis. Results Eight unique variations involving the posterior division of the internal iliac artery and the inferior vesical, obturator, and internal pudendal arteries were noted. These included the unusual arch-like formation of the posterior division; the origins of the obturator artery from the arch of posterior division, and with the superior vesical and uterine arteries from a common trunk of the anterior division of the internal iliac artery; the origin of the internal pudendal artery with the vaginal artery from an unusual variant branch; and the origin of the inferior vesical artery from the obturator artery. Conclusions Understanding the branching pattern of the internal iliac artery may assist in the prevention of vascular trauma and surgical hemorrhage during pelvic laparoscopy, total hysterectomy, and pelvic tumour resection, as well as other complications such as ureteral injury during ligation. If indistinguishable, the variable branching pattern of the internal iliac artery may also lead to erroneous therapeutic embolization.