Vessels at risk in laparoscopic gynecological surgery
An understanding of the surgical anatomy of the vessels at risk of injury during laparoscopic surgery is an important step in reducing vessel injury. Anterior abdominal wall vessels and retroperitoneal vessels can all be injured during the Veress needle, primary trocar, or secondary port insertion. In addition to injuries on entry, vessels can be damaged during dissection, electrosurgery, or use of other energy devices.

Inferior epigastric artery
The inferior epigastric artery arises from the external iliac artery, close to the insertion of the round ligament. It pierces the transversalis fascia and runs along the transverse abdominis muscle and the rectus sheath. At the umbilicus it lies between 3 cm and 6 cm from the midline, at the pubic symphysis it lies 1.2–7.5 cm from the midline. There is a ‘safe zone’ where ports can be inserted with a low likelihood of injuring the inferior epigastric artery. This could be from <1 cm from the midline or >8 cm from the midline. Insertion of ports more than two-thirds along the line between the midline and the anterior superior iliac spine will also fall in this ‘safe zone’.

Direct visualization of the inferior epigastric artery by Doppler ultrasound or transillumination has been recommended, but this becomes more difficult with increasing BMI. Tinelli et al.16 describe a ‘yellow zone’ which exists one-third of the way from the anterior superior iliac spines to the umbilicus and can be identified easily in those with increased BMI (Figure 2). This yellow zone can be used for safe placement of secondary ports. Inserting ports perpendicular to the abdominal wall also helps to minimize inadvertent inferior epigastric artery injury.

Most surgeons use the umbilicus as the site for the insertion of the Veress needle and primary trocar. During the insertion of these instruments, the aorta, inferior vena cava, and common iliac vessels are at risk of injury. The abdominal aorta bifurcates into the right and left common iliac arteries at the level of L4. In the supine position, the aortic bifurcation ranges from 5 cm cephalad to 3 cm caudal to the umbilicus. In the Trendelenburg position, it ranges from 3 cm cephalad to 3 cm caudal to the umbilicus. Aortic bifurcation occurred caudal to the umbilicus in 33% of laparoscopies carried out in a Trendelenburg position versus 11% in a supine position.

This supports the insertion of the Veress needle and first trocar in the supine position before raising the legs into the Trendelenburg position. These findings were not affected by the patient’s BMI. If the aorta is injured, the hemorrhage may be visible during primary survey of the abdomen on entry with the camera. However, in cases of small vessel puncture, the bleeding may result in the formation of a retroperitoneal hematoma that is not immediately apparent. Surgeons should respond promptly to any concern from the anesthetist regarding haemodynamic instability, such as unexpected hypotension or tachycardia, and consider the presence of any bleeding, including retroperitoneal.

Common iliac arteries
As the aortic bifurcation occurs just to the left of the midline, the right common iliac artery is at higher risk of injury during instrumentation of the umbilicus than the left. Keeping the Veress needle and trocar in the midline during entry minimises the risk of injury to these vessels.

Venous system
The vena cava is formed by the confluence of the common iliac veins. This occurs anterior to the L5 vertebra, caudal to the bifurcation of the aorta, and approximately 2.5 cm to the right of the midline. An injury to the vena cava is therefore more likely when a trocar is inserted next to the midline instead of in the midline. The left iliac vein crosses the midline caudal to the umbilicus and can be injured even by a midline trocar. Sharp dissection may cause an injury that requires repair. The walls of the major veins are delicate and injury can lead to catastrophic bleeding. Blunt dissection along the common iliac vein, inferior vena cava, pelvic sidewall or the presacral area can avulse small tributaries from larger veins with resultant hemorrhage.

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