Final answer:
Immediate hemostasis is imperative when the common iliac vein is injured during a pelvic lymphadenectomy to prevent hypovolemia, which involves methods like direct pressure, suture repair, or clamping. The internal iliac vein drains into the common iliac vein, which then flows into the inferior vena cava at the level of L5.
Step-by-step explanation:
During a pelvic lymphadenectomy, if the common iliac vein is injured, causing profuse bleeding, the best course of action is to achieve immediate hemostasis. This may involve direct pressure, suture repair of the vein, or clamping. It's critical to control the bleeding to prevent hypovolemia and other complications. As part of the management, the internal iliac vein, which drains the pelvic organs and integument and is formed from several smaller veins in the region, flows into the common iliac vein. The common iliac vein then flows into the inferior vena cava at the level of L5, formed by the confluence of the external and internal iliac veins near the inferior portion of the sacroiliac joint. The left common iliac vein additionally drains the sacral region. Immediate medical intervention and vascular surgery consultation are essential in such a situation.