Introduction To evaluated the feasibility of extraperitoneal sentinel lymph node biopsy (SLNB) by vaginal natural orifice transluminal endoscopic surgery (vNOTES) in patients with a non-prolapsed uterus and low-risk endometrial cancer.

Methods A 54-year old woman visited because of vaginal bleeding that started three months ago. Endometrial biopsy revealed grade 1 endometrioid endometrial cancer, and imaging studies showed no abnormal finding. We tried vNOTES staging operation with extraperitoneal SLNB. First, each 1 ml of indocyanine green (ICG) diluted at 1.25 mg/ml was injected into the submucosa and stroma at 3 and 9 o’clock of the cervix. Second, we opened the mid-vagina between the cervix and vaginal orifice where the pelvic floor muscles were palpated. Third, a space was secured by placing a finger upward and outward after ensuring the opening space of the mid-vagina. Thereafter, we inserted single port trocar through the opening, and then we found the para-cervix including the pelvic autonomic nerves, and the obturator nerve. After peeling off the pelvic vessels and nerves and ureter, we found the sentinel lymph node near the external iliac vessel, and resected it. Then, we performed vNOTES hysterectomy, and she was discharged on the second day of surgery without any complications.

Conclusions vNOTES staging operation with extraperitoneal SLNB may be feasible, and the determination over the extraperitoneal opening may be important to ensure the adequate view to identify the pelvic structure for patients with a non-prolapsed uterus and low-risk endometrial cancer.