To avoid injury to vascular structures and resultant hemorrhage while inserting a trocar into the anterior abdominal wall during laparoscopy, the surgeon should keep in mind certain anatomic relationships. The inferior epigastric artery is a branch of the external iliac artery, arising from the parent vessel at the medial border of the inguinal ligament and coursing cephalad lateral to and posterior to the rectus sheath at the level of the arcuate line. It lies about 1.5 cm lateral to the medial umbilical fold, which marks the site of the obliterated umbilical artery. During laparoscopy the inferior epigastric artery almost always can be visualized between the obliterated umbilical artery medially and the insertion of the round ligament through the inguinal canal laterally. This artery can be traced visually cephalad, allowing for safe insertion of lateral port site. The aortic bifurcation occurs at the level of L4 to L5, just above the sacral promontory. Palpation of the sacral promontory to guide trocar insertion allows the surgeon to avoid the major vascular structures in this area (see Fig. 23.4 in Chapter 23). The left common iliac vein lies medial to the artery and is at risk of injury during umbilical laparoscopic trocar insertion and during dissection for sacrocolpopexy.
Figure 5.6 The collateral blood vessels of the pelvis. (Modified from Kamina P. Anatomie gyn´ etricale. Paris, France: Maloine Sa ´ ecologique et obst´ Editeur, 1984:125, with permission.)
Lymphatics The pelvic lymph nodes are generally arranged in groups or chains and follow the course of the larger pelvic vessels, for which they are usually named. Smaller nodes that lie close to the visceral structures are usually named for those organs. Lymph nodes in the pelvis receive afferent lymphatic vessels from pelvic and perineal visceral and parietal structures and send efferent lymphatics to more proximal nodal groups. The number of lymph nodes and their exact location is variable; however, certain nodes tend to be relatively constant: 1.
Obturator node in the obturator foramen, close to the obturator vessels and nerve 2.
Nodes at the junction of the internal and external iliac veins
Table 5.3 Collateral Arterial Circulation of the Pelvis 3.
Ureteral node in the broad ligament near the cervix, where the uterine artery crosses over the ureter 4.
The Cloquet or Rosenm¨uller node—the highest of the deep inguinal nodes that lies within the opening of the femoral canal
Figure 5.7 illustrates the pelvic lymphatic system. Table 5.4 outlines the major lymphatic chains of relevance to the pelvis and their primary afferent connections from major pelvic and perineal structures. There are extensive interconnections between lymph vessels and nodes; usually more than one lymphatic pathway is available for drainage of each pelvic site. Bilateral and crossed extension of lymphatic ﬂow may occur, and entire groups of nodes may be bypassed to reach more proximal chains.
The natural history of most genital tract malignancies directly reﬂects the lymphatic drainage of those structures, although the various interconnections, different lymphatic paths, and individual variability make the spread of malignancy somewhat unpredictable. Regional lymph node metastasis is one of the most important factors in formulation of treatment plans for gynecologic malignancies and prediction of eventual outcome.
Nerves The pelvis is innervated by both the autonomic and somatic nervous systems. The autonomic nerves include both sympathetic (adrenergic) and parasympathetic (cholinergic) fibers and provide the primary innervation for genital, urinary, and gastrointestinal visceral structures and blood vessels.