CT of pelvic extraperitoneal spaces: an anatomical study in cadavers

Aim: To evaluate the pelvic extraperitoneal compartments and communications with abdominal retroperitoneal spaces. Material and methods: Helical computed tomography (CT) was used to image the abdomen and pelvis after injection of 800 ml of dilute (1 in 25) contrast material into prevesical, perivesical and perirectal spaces in eight embalmed cadavers. Axial images and multiplanar reconstructions were reviewed to determine flow pathways. Results: The prevesical space was injected in four cadavers, the perivesical space in two and the perirectal in two. After the four prevesical space injections, communication was seen with the perivesical (four of four), perirectal (one of four) and abdominal extraperitoneal spaces (posterior pararenal space in all, anterior pararenal space in two of four, and perirenal space in three of four). After the two perivesical injections, communication was seen with the prevesical (two of two), perirectal (two of two) and abdominal extraperitoneal spaces (posterior pararenal in two of two, anterior pararenal in two of two, and perirenal space in two of two). After the two perirectal space injections, communication was seen with the prevesical (two of two), perivesical (one of two) and abdominal extraperitoneal spaces (posterior pararenal in two of two, anterior pararenal in two of two, and perirenal space in one of two). Conclusion: The extraperitoneal spaces of the pelvis comprise three communicating compartments: the prevesical space, the perivesical space, and the perirectal space. The perirectal space, previously thought to be separate, communicates with the perivesical and the prevesical spaces. Intercommunication occurs both between the pelvic extraperitoneal spaces and with abdominal retroperitoneal spaces.