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Measures to deal with life-threatening obstetric haemorrhage have been outlined previously, including the use of oxytocic agents, uterine tamponade, uterine compression sutures and hysterectomy. The aim of this chapter is to describe the role of major pelvic vessel ligation or embolization when other methods to control bleeding have failed.
The main indications for pelvic vessel ligation or embolization are bleeding of uterine origin in which preservation of the uterus is sought, and in vaginal and paravaginal trauma when local measures fail to achieve haemostasis. These indications may include but are not limited to haemorrhage from placenta praevia, placenta accreta, abruptio placentae, uterine atony unresponsive to oxytocics, extension of lower segment caesarean incision into the broad ligament or vagina, uterine rupture, paravaginal haematoma, and extensive cervical and/or vaginal lacerations. Pelvic vessel ligation can also be vital in controlling postoperative haemorrhage after caesarean hysterectomy.
Intraoperative haemorrhage occurring at the time of caesarean section, or at laparotomy for uterine rupture, may require surgical ligation. Postpartum haemorrhage following vaginal delivery, refractory to aforementioned interventions, may now often be ideally managed by interventional radiology where pelvic vessel embolization will often avoid the need for a laparotomy.
At the end of the 19th century, Dr Howard Kelly described ligation of internal iliac artery as a method for controlling pelvic haemorrhage in a woman with a locally advanced cervical cancer. Although Dr Kelly is often credited with the initial description, Dr Venacio Tajes in Uruguay described the procedure some years previously as treatment of a gluteal aneurism. Internal iliac artery ligation was first used in obstetrics in 1950. In 1968, Dr Burchell described the haemodynamic changes induced by internal artery ligation which demonstrated that due to extensive pelvic collateral anastomosis it is not a particularly effective method of achieving pelvic haemostasis when used in isolation.
The aorta bifurcates at the level of L4 and the right common iliac artery crosses anterior to the right common iliac vein. The common iliac artery bifurcates at the level of the lumbosacral junction in front of the sacroiliac joint. The ureter enters the pelvis by crossing the bifurcation of the right common iliac artery but crosses the left common iliac artery. The external iliac artery runs lateral and superior, while the internal iliac (hypogastric) artery descends inferomedially into the pelvis with the ureter tracking medially. Posterior to the internal iliac artery lies the internal iliac vein, which is very close and vulnerable to trauma during attempts to ligate the artery. Controlling haemorrhage from the internal iliac artery can be extremely difficult and when it occurs it is best to achieve proximal control using packs and distal control, with pressure on the common iliac vein. If vascular surgery backup is available, it should be called.
The internal iliac artery has several divisions but terminates as the obliterated umbilical artery on the anterior abdominal wall. The internal iliac artery typically runs for 3–4 cm before dividing into anterior and posterior divisions. The posterior division divides into three branches: the iliolumbar, lateral sacral and the superior gluteal arteries – the latter leaves the pelvis through the greater sciatic foramen to supply the gluteal muscles. The anterior division usually has eight branches: the superior and inferior vesical, obturator, middle haemorrhoidal, uterine, vaginal and the terminal internal pudendal and inferior gluteal arteries; however, significant variations exist and and the internal pudendal and obturator arteries can arise from the posterior division ( Fig. 38.1 ).
A clear understanding of the major pelvic collateral anastomosis is a key component to achieving pelvic haemostasis. Many of the pelvic collateral anastomoses involve the posterior branch of the internal iliac artery, which highlights why ligation or embolization of the anterior division may not always be successful. The three main upper collateral anastomoses are:
the lumbar artery from the aorta and anastomoses with the iliolumbar artery from the posterior division of the internal iliac artery
the middle sacral artery from the aorta anastomoses with the lateral sacral artery of the internal iliac artery
the superior haemorrhoidal artery, which is the terminal branch of the inferior mesenteric artery from the aorta, joins the middle haemorrhoidal artery of the internal iliac artery ( Fig. 38.2 ).
Other collaterals that may link the aorta with branches of the internal iliac artery include: the ovarian artery and the uterine artery; the femoral artery with the internal pudendal artery via the profunda femoris and femoral circumflex vessels; and the circumflex iliac arteries from the external iliac artery with the superior gluteal artery of the internal iliac artery. Finally, the obturator artery can also communicate with the circumflex arteries, with the internal pudendal artery and with the inferior gluteal artery (sciatic artery).
Classical descriptions of uterine vascular supply focus on the uterine and ovarian artery. The uterine fundus and body are irrigated by the uterine and ovary arteries (sector 1) and are well described. However, vascular supply to the lower uterine segment, cervix and the upper vagina arises by the pudendal internal artery (sector 2) and is less well described in the literature. Sector 1 is dependent on the anterior branch of the internal iliac artery, while sector 2 supply may come from either the anterior or posterior division of the internal iliac artery and is more prone to being supplied by additional collaterals from the aortic, external iliac and femoral anastomosis. Consequently, haemorrhage from sector 1 can often be controlled by uterine artery ligation or embolization (90% of blood flow). Haemorrhage from sector 2, often the site of bleeding from severe placenta accreta syndrome, or after a difficult instrumental delivery, may require selective vessel occlusion by means of bilateral common iliac artery or infrarenal aortic balloon occlusion, clamping or compression ( Fig. 38.3 ).
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