Laparoscopic En Bloc Para-aortic Lymphadenectomy up to the Renal Vein for Colorectal Cancer: How I do it?

BACKGROUND: Primary tumor resection with simultaneous para-aortic lymph node dissection has curative potential in selected patients with isolated infrarenal para-aortic lymph node metastasis secondary to colorectal cancer. However, para-aortic lymph node dissection is technically challenging, and en bloc resection is difficult. Traditional piecemeal removal may increase the risk of missing lymphatic tissue and contribute to local recurrence. IMPACT OF INNOVATION: A modified "lawn-mowing" technique is introduced for en bloc para-aortic lymph node dissection that simplifies this complex procedure. By initially identifying anatomical boundaries and then systematically removing lymph nodes in a sequential "lawn-mowing" manner, this approach maximizes lymphatic clearance and facilitates appropriate vessel ligation, potentially reducing recurrence and complications. TECHNOLOGY MATERIALS AND METHODS: There are 2 steps in the technique: (1) Identification of boundaries: establishing the left (left ureter, gonadal vessels and psoas), distal (left common iliac vein level), right (right ureter, gonadal vessels and psoas), and proximal (left renal vein) boundaries. (2) En bloc resection: sequential dissection from distal to proximal and right to left in a "lawn-mowing" pattern, collecting all para-aortic lymph nodes up to the left renal vein and ligating the main lymphatic vessels, superior and inferior to the left renal artery. Key considerations include preserving the sympathetic ganglia and avoiding injury to hemorrhage-prone veins. PRELIMINARY RESULTS: Successful en bloc para-aortic lymph node resection was achieved in a 26-year-old female with sigmoid colon cancer and para-aortic metastasis. Duration of surgery was 380 min, with 100 mL of blood loss. The patient was discharged without complications. Histopathological examination revealed 2/23 positive para-aortic lymph nodes. At the nine-month follow-up, there was no recurrence or formation of lymphocysts. CONCLUSIONS AND FUTURE DIRECTIONS: En bloc para-aortic lymph node resection using the "lawn-mowing" technique, after identification of boundaries, is feasible and reproducible. This simplified approach reduces the risk of lymphatic residue. Further evaluation in a larger series is required to assess oncological and functional outcomes. See New Technology Report Video.