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Currently, the consensus among authors, both domestically and internationally, leans towards the belief that the distal approach is more conducive than the proximal in locating the retroperitoneal space on the right side and  performing lymph node dissection with high ligation of vascular roots. Furthermore, through practical experience, we have come to realize that the distal approach, involving flipping the cecum towards the proximal side through the dorsal middle entry route, is more likely to accurately identify the retroperitoneal space compared to the abdominal middle entry route from below the ileocolic vessels. When performing the distal approach, initiating dorsal separation to the pancreatic head first, followed by abdominal D3 lymph node dissection or using a mixed approach, may be easier to master.

(1) Distal abdominal entry route: With the head elevated at 30° and the patient in a left lateral position at 15°, lifting the mesenteric pedicle of the cecum reveals a natural fold known as the membrane bridge. Using an ultrasonic knife, a small incision is made to hollow it out, causing the membrane bridge to rise. The incision is made obliquely, entering the gap between the small intestine and ascending colon and under high-tension traction, easy access to the retroperitoneal space behind the ascending colon is achieved. This solitary incision line will inevitably converge with the vertical projection line of the superior mesenteric vein (SMV).

(2) Distal dorsal entry route: With the head lowered at 30° and the patient in a left lateral position at 15°, flipping the cecum towards the proximal side, an incision is made along the white-yellow boundary line approximately 1.0cm above the right iliac artery. Under high-tension traction, easy access to the retroperitoneal space behind the ascending colon is achieved, revealing the horizontal part of the duodenum. Opening the original posterior peritoneum at its upper edge enters the posterior space between the transverse colon and the duodenum. Internal separation reveals the right side of the SMV, while external separation reaches the groove beside the right colon, avoiding compression of the cecum or ascending colon tumor. Elevating the head at 30° and maintaining a left lateral position at 15°, placing the cecum back in its original position, similar to the abdominal entry route, an incision is made along the oblique fold below the mesenteric pedicle of the cecum, entering the gap between the small intestine and ascending colon. An oblique incision of 3-4cm towards the SMV, piercing the posterior leaf of the mesentery of the ileum, connects with the previously separated retroperitoneal space behind the ascending colon.

(3) Distal mixed entry route (abdominal first, then dorsal): In clinical practice, while seeking the retroperitoneal space behind the ascending colon through the distal abdominal entry route, the corresponding posterior leaf of the mesentery of the ileum is inadvertently cut through. This inadvertently created incision line of the distal dorsal entry route can be enlarged without changing the position, thus completing the aforementioned dorsal entry route. Therefore, before selecting the entry route, it is advisable to explore the posterior side of the terminal mesentery of the ileum. If there is no adhesion to the right iliac fossa, this route can be adopted.

These three distal entry routes have their characteristics in terms of surgical operation and lymph node dissection. In actual practice, surgeons will choose the most suitable entry route based on the specific conditions of the patient.