The fusion fascia of Fredet: an important embryological landmark for complete mesocolic excision and D3-lymphadenectomy in right colon cancer

Background: The fusion fascia of Toldt is a well-known landmark used by colorectal surgeons. On the contrary, the fusion fascia of Fredet (the plane between the ascending mesocolon and the visceral duodenal-pancreatic peritoneum) still remains a neglected embryological structure. Aim of this study was to provide an anatomic description of this fascia and its application to minimally invasive D3-lymphadenectomy (D3-L) and complete mesocolic excision (CME) for right colon cancer. Methods: First phase: Cadaveric dissection and anatomic description of the fascia of Fredet. Second phase: prospective evaluation of its surgical application in a consecutive series of laparoscopic right hemicolectomies with CME and D3-L at a tertiary hospital. Results: The fascia of Fredet was identified and dissected in one fresh and two formalin-fixed cadavers. The trunk of Henle and the medial border of the superior mesenteric vein defined the medial limit of this embryologic plane. Seventeen patients were operated on. Laparoscopic dissection of the fascia of Fredet was possible in every patient. Median operative time was 210 (120–380) min. There were no major postoperative complications. All cases were adenocarcinomas, except one adenomatous polyp. T stage was Tis in three, T2 in two, T3 in seven, and T4 in five patients. Median number of harvested lymph nodes was 24 (9–39). Lymphatic invasion was found in six patients. All resections were classified as satisfactory mesocolic excision and R0. Median postoperative length of stay was 6 (4–20) days. Median follow-up time was 28 (16–41) months. Local and distal recurrence rate was 0. Conclusion: The fusion fascia of Fredet is useful to achieve CME and D3-L in right colon cancers with reduced risk of intraoperative complications. This structure is particularly suitable for minimally invasive surgery; therefore, we encourage awareness of the fascia of Fredet by colorectal surgeons.