In this video, we will review the avascular planes of the pelvis. The surgeon should be thoroughly familiar with these avascular spaces of the pelvis as well as their relationships with each other in order to restore normal anatomic relationships in the case of distorted anatomy, to avoid injury to the viscera and vasculature, to perform pelvic reconstruction, and to resect pelvic pathologies such as endometriosis or cancer. Important potential spaces in the pelvis include the anterior and posterior cul-de-sacs, the vesico-vaginal space, para-vesical space, para-rectal space, and recto-vaginal space. The anterior cul-de-sac is also known as the vesico-uterine pouch and refers to the space between the dome of the bladder and the anterior surface of the uterus. Here is a view of the posterior cul-de-sac, otherwise known as the recto-uterine space or pouch of Douglas. This is the space between the cervix and the rectum. This space usually allows safe entry into the peritoneal cavity during vaginal hysterectomy. Here the posterior vaginal epithelium has been incised and the posterior cul-de-sac has entered sharply, with decreased risk of rectal injury because of the existence of this potential space posterior to the uterus. The vesico-vaginal space refers to the plane between the bladder and the vagina. Here is an abdominal view of the vesico-vaginal space. The bladder flap is dissected during hysterectomy and the vesico-vaginal space is located in the midline, with its boundaries as the bladder pillars laterally and the bladder anteriorly. The bladder can be dissected well off of the anterior surface of the vagina. During vaginal hysterectomy, the vaginal epithelium and bladder are dissected off of the cervix and lower uterine segment. The vesico-uterine fold should be identified and the anterior cul-de-sac is entered. A finger is placed to confirm there is no injury to the bladder. Development of the paravesical space is an essential step in the performance of a radical hysterectomy and or pelvic lymphadenectomy. It also facilitates identification of the course of the distal ureter between the cardinal ligament and the bladder, which may be valuable for benign hysterectomies where the anatomy is distorted as in the case of a cervical or broad ligament fibroid. This patient is undergoing a radical trachelectomy for cervical cancer with uterine preservation. Retroperitoneal access is achieved via transection of the round ligament. The bladder appears blue due to the installation of dilute indigocarmine dye. This space is developed by opening the anterior leaf of the broad ligament and first identifying the external iliac artery and vein. The adipose and areolar tissue located between the superior vesicle and obliterated umbilical artery and the external iliac vessels towards the bladder medially is bluntly dissected and exposes this space. The paravesical spaces are paired spaces that lie inferior to the cardinal ligaments. Their boundaries are the bladder pillars and retropubic space medially, the obturator and maternus muscle and the pelvic sidewalls laterally, and the cardinal ligament superiorly. The anterior leaf of the broad ligament forms the roof of the paravesical space while the levator ani adds a floor. The uterine artery is identified at its origin off the internal iliac artery and as it crosses over the ureter and is clipped during this procedure. The pararectal spaces lie in the retroperitoneum bilaterally just superior to the cardinal ligament. Its borders are formed inferiorly by the cardinal ligament, medially by the utero-sacral ligament, rectal pillar, ureter, and ovarian vessels, laterally by the internal iliac vessels and piriformis muscles, and inferiorly by the levator ani muscles and coccygeus muscle-sacrospinous ligament complex. This space is developed by incising the broad ligament in its cephalic direction lateral to the ovarian vessels. The ovarian vessels and the ureter are adherent to the medial leaf of the broad ligament. Adhesion lateral to these structures and medial to the internal iliac vessels allows the development of the pararectal space which can be carried all the way down to the levator ani muscles. Here is a view of the right pararectal space. Endometriotic implants may occur in this space as in this patient. The left pararectal space is now visualized. It is often developed at the time of radical hysterectomy for cervical cancer or when the posterior cul-de-sac is obliterated due to endometriosis. This patient is status post a prior hysterectomy. EASizers are in the vagina and in the rectum. The peritoneum overlying the rectovaginal septum is incised and the loose areolar tissue can be dissected bluntly or sharply or with monopolar cautery. This area should be relatively bloodless. If bleeding is encountered, the surgeon may be too close to the vagina or to the rectum. Endometriosis can infiltrate this area and obliterate the posterior cul-de-sac.

avascular planes

pelvis

surgeons

anatomy restoration

endometriosis