Biomechanical Formation Mechanism of the “Avascular Plane” in the Pelvis and Retroperitoneum: Redefining Surgical Cleavage Planes Created by Fetal Poisson Compression and Shear Stress

Background

The "avascular plane," which surgeons navigate during total mesorectal excision (TME) and robot-assisted radical prostatectomy (RARP), has conventionally been explained as a static boundary, such as an "embryological plane" where different developmental compartments adjoin, or a "fusion fascia" where tissues contact during embryogenesis. However, these classical models harbor fundamental contradictions; they cannot causally explain clinical facts such as why blood vessels cannot invade despite the mesenchyme sharing the same mesodermal origin, why only nerves remain, the continuity between the lateral ligament and the neurovascular bundle (NVB), and the pronounced bilateral asymmetry of the prehypogastric nerve fascia.