Novel anatomical concept and standardized technique for single-port laparoscopic para-aortic lymphadenectomy.

e17621 Background: Para-aortic lymphadenectomy (PAL) plays an important role in the treatment of gynecological cancers. Laparoscopic PAL is a technically challenging procedure, and the difficulty is markedly increased under single-port laparoscopy. To address this challenge, we developed a standardized technique based on a novel anatomical concept to reduce the difficulty of single-port laparoscopic PAL. Methods: A modified Trendelenburg positioning was adopted with the operating bed tilted 30 degrees to the right. This positioning led to a gravitational displacement of the small intestines to the upper right abdomen, forming an angular structure between the inferior mesenteric vein and the ascending part of the duodenum. We designated this structure as renal vein angle since the apex of this angle accurately indicates the location of left renal vein, providing an anatomical landmark for PAL. By suspending the peritoneum on several strategically selected points, all small intestines can be effectively confined to the right side of the renal vein angle, thereby achieving a stable operating space. With this standardized technique, complete exposure can be attained at the beginning of surgery, allowing for precise and efficient processing of PAL up to the left renal vein. All the surgeries were performed via single-port laparoscopy by a young gynecologic oncologist. The surgical videos were recorded and analyzed, with all clinical data prospectively collected. The primary objective of this study is to evaluate the stability and safety of the standardized technique. Results: From Feb 2022 to Dec 2024, a total of 48 consecutive patients with gynecological cancers underwent single-port laparoscopic surgeries involving PAL. The cohort included 40 endometrial cancer, 6 primary ovarian cancer, 1 recurrent ovarian cancer, and 1 recurrent cervical cancer. The median age was 54 years (range 18-67). The median BMI was 25.6 kg/m² (range 18.1-51.4). All PALs were successfully completed using standardized technique with skeletonization of left renal vein, venous cava and aorta. The median number of para-aortic lymph nodes dissected was 20 (range 12-37). The median operating time for PAL was 95 minutes (range 54-285), and the median estimated blood loss was 30 ml (ranged 5-150). Intraoperative complications included two minor vascular branch injuries and one inferior mesenteric artery injury. Postoperative complications included three chylous fistulas and two lymphocysts. There was no PAL-associated major complication, conversion to laparotomy, or need for adding trocar. Seven patients were found to have nodal metastasis on postoperative pathology. No recurrence was observed during a median follow-up time of 12 months (range 1-34). Conclusions: Our standardized technique provides a reliable and safe approach with reduced difficulty for single-port laparoscopic PAL for gynecological cancers.