Lymph Node Sampling
In contrast to a complete lymphadenectomy (see Unit 1, Chapter 12), selective lymph node sampling is performed during simple hysterectomy for women who have been diagnosed with adenocarcinoma of the endometrium (see Unit 1, Chapter 13).
The lymph nodes typically sampled include the external iliac, internal iliac, common iliac, obturator, and periaortic nodes. These lymph nodes are closely associated with the large arteries and veins of the pelvis (Fig. 40–1).
The external iliac node sample is obtained by retracting the external iliac artery and removing some of the fatty tissue between the artery, the external iliac vein, and the lateral boundary formed by the psoas major muscle (Figs. 40–2A, 40–3 through 40–5).
The vein retractor is moved to the external iliac vein, which is gently elevated. Then with the use of ring pick-ups, some of the node-containing fatty tissue of the obturator fossa is teased away from around the obturator nerve (see Figs. 40–2B, 40–6 through 40–9).
Next, nodal tissue is excised from the hypogastric artery where it joins the external iliac artery to form the common iliac artery. Here the ureter must be identified and retracted medially to gain exposure (Figs. 40–2C and 40–10).
The tissue at the junction of the common iliac arteries and the aorta is sampled next (Figs. 40–2D and 40–11). Periaortic nodes are excised above the level of the takeoff of the inferior mesenteric artery (Figs. 40–12 and 40–13). The fat between the aorta and the inferior vena cava is carefully dissected and sampled (see Fig. 40–2E). When fatty tissue containing lymphatic tissue is cut, it typically bleeds. Therefore, when retroperitoneal lymph node sampling is performed, vascular clips should be applied to secure the small venules and arterioles (Fig. 40–14). Occasionally, it may be necessary to use a 3-0 or 4-0 Vicryl as a suture-ligature to achieve appropriate hemostasis (see Fig. 40–14).
Sampling should continue upward to the origin of the ovarian arteries from the aorta and of the ovarian veins from the vena cava and left renal vein areas (see Fig. 40–2F). For vulvar carcinoma, the lowest node in the external iliac chain is sampled. This can be done extraperitoneally by locating the inferior epigastric artery and tracing it to the iliac vessels at the point where the vessels cross under the inguinal ligament. The node is located just medial to the external iliac vein and lies in the femoral canal (Fig. 40–15A
