For repair of an anterior vaginal prolapse (a cystocele), the two most important landmarks are the ischial spine and the junction of the inferior pubic ramus with the body of the pubic bone. This is because the “white line” of para-vaginal support goes from one of these points to the other. The anatomical orientation of the anterior vaginal wall must also be delineated. Overlying the lower third is the urethra, and overlying the middle third is the trigone of the bladder, an area of significant innervation. Overlying the upper third of the anterior vaginal wall is the bladder itself. The ureters travel across this upper third from lateral to medial, entering the bladder at the junction of the middle third and the upper third of the vagina.
A 3-cm anterior colpotomy incision is made in the upper third of the vagina. We stay away from the middle of the anterior vaginal wall so that innervation to the bladder is not disrupted, and so that the area underneath the urethra remains fresh for placement of a midurethral transvaginal tape, if needed.
The incision to the anterior vaginal wall should be a full-thickness incision that leaves the white, shiny pubo-cervical fascia on the back of the vaginal epithelium. Once you pass through this fascia, you are in the true vesicovaginal space, and the visceral fascia that surrounds the bladder can be seen.
A curved Mayo scissors, or your finger, can then be used to gently develop the lateral space between the bladder and the vaginal epithelium. There should be minimal bleeding. (If there is more than minimal bleeding, you're either in the wrong dissection plane or you're encountering significant scar tissue from your patient's previous surgery.)
Your goal is to work laterally, so that you can actually feel the tough parietal fascia that covers the obturator muscles.
When you feel the junction of the inferior pubic ramus with the body of the pubic bone—one of the two most important landmarks—you then can slide your finger along the obturator internus fascia right down to the ischial spine. That distance is only about 5–6 cm. By doing so on both sides, the bladder is mobilized away from the anterior vaginal epithelium, and the bladder and ureters are mobilized away from the pelvic side walls. Again, there should be minimal blood loss (no more than 50 cc).
The cannula-equipped curved metal guides must then be passed through the inner thighs. A first incision (no more than 5 mm) is made at the level of the urethra, about 1 cm lateral to the inferior pubic ramus, which you can palpate through the skin of the thigh. This is for the anteromedial, or superficial, passage. The second incision (of the same size) is made at 1 cm lateral and 2 cm posterior to the first mark. This is for the posterolateral, or deep, passage. I always work through the deep passage first. With its tip perpendicular to the skin, I push the cannula-equipped guide straight in until I feel the tip pop through the fascia lata. I then bring the handle of the guide up, so that the directional force is parallel to the fascial white line.
The goal in this deep passage is to pass the guide through the posterior aspect of the obturator membrane and through the obturator internus muscle so that the tip of the cannula is about 1 cm inferior (and a bit anterior) to the ischial spine as it pops through the muscle into the paravaginal space. My finger waits there to feel the tip pass through the fascia of the obturator internus muscle. I then feed a small dull curette into the paravaginal space with my finger and slip it over the cannula, and my assistant carefully removes the guide.
The retrieval device—a piece of long plastic tubing, in essence, with a loop at the end—can then be passed through the cannula. When I feel the loop come through, I entrap it against the end of the curette and pull both the loop and the retrieval device out of the vagina. (Some surgeons hook the loop with a finger, but I find the curette helpful.)
The superficial passage involves the same maneuvers, except this time I'm looking for the junction of the inferior pubic ramus with the body of the pubic bone. With my finger in the paravaginal space, I dissect any intervening tissue away from the fascia of the obturator internus muscle at this junction. I also ensure that the bladder is mobilized away from the central portion of the anterior vaginal epithelium, so that the proximal portion of the mesh—an apical flap—can be attached to the apex of the vagina. (This apical flap also helps repair the anterior enterocele that usually exists with the cystocele.)