New insights into autonomic nerve preservation in high ligation of the inferior mesenteric artery in laparoscopic surgery for colorectal cancer.

Aim: To take a deeper insight into the relationship between the root of the inferior mesenteric artery (IMA) and the autonomic nerve plexuses around it by cadaveric anatomy and explore anatomical evidence of autonomic nerve preservation in high ligation of the IMA in laparoscopic surgery for colorectal cancer.

Methods: Anatomical dissection was performed on 11 formalin-fixed cadavers and 12 fresh cadavers. Anatomical evidence-based autonomic nerve preservation in high ligation of the IMA was performed in 22 laparoscopic curative resections of colorectal cancer.

Results: As the upward continuation of the presacral nerves, the bilateral trunks of SHP had close but different relationships with the root of the IMA. The right trunk of SHP ran relatively far away from the root of IMA. When the apical lymph nodes were dissected close to the root of the IMA along the fascia space in front of the anterior renal fascia, the right trunk of SHP could be kept in suit under the anterior renal fascia. The left descending branches to SHP constituted a natural and constant anatomical landmark of the relationship between the root of IMA and the left autonomic nerves. Proximal to this, the left autonomic nerves surrounded the root of the IMA. Distally, the left trunk of the SHP departed from the root of IMA under the anterior renal fascia. When high ligation of the IMA was performed distal to it, the left trunk of SHP could be preserved. The distance between the left descending branches to SHP and the origin of IMA varied widely from 1.3 cm to 2.3 cm.

Conclusions: The divergences of the bilateral autonomic nerve preservation around the root of the IMA may contribute to provide anatomical evidence for more precise evaluation of the optimal position of high ligation of the IMA in the future.