New classification system for radical rectal cancer surgery based on membrane anatomy

Figure 3 Laparoscopic observation. A: The anterior trunks of internal iliac vessels and most of their branches run in the middle space; B: The lateral space mainly contains the neural structures (obturator nerve, sciatic plexus, etc.) in addition to the obturator vessels; C: Type A and type B surgeries are performed in the medial and middle spaces, respectively. Type A surgery corresponds to the urogenital fascia-preserving total mesorectal excision (TME), and type B surgery corresponds to the classical TME.