For more than 100 years, gynecologic surgeons have been taught that the vaginal defects causing anterior and posterior vaginal prolapse result either from generalized midline stretching or thinning of the pubocervical fascia, or from lateral or paravaginal injuries.
The pubocervical fascia is a common surgical term for the fibromuscular coat of the vaginal epithelium. Histologically, it is indistinguishable from the deep vaginal wall and does not look like a distinct fascial layer. Clinically, however, it can be identified both abdominally and vaginally, and surgically, it can be dissected from the underlying fibromuscular tissue of the vagina in the vesicovaginal space via the vaginal approach.
A trapezoid-shaped structure of pubocervical fascia serves as a kind of hammock on which the bladder is believed to passively rest. Some believe that visceral bladder connective tissue is the supportive tissue for the bladder, but most refer to this connective tissue as pubocervical fascia – even though usage of the term is not quite anatomically correct and is not used consistently in the literature.
The true pubocervical fascia extends from the pubic bone anteriorly and laterally to the arcus tendineus fascia pelvis. Its proximal posterior edge is attached to the pericervical ring. This supportive fascia is where the defects responsible for anterior-wall prolapse have traditionally been believed to occur.
Midline plication, as well as paravaginal repair involving lateral attachment of the vagina to the arcus, have thus been the surgical approaches of choice for anterior-wall prolapse and cystocele. We have relied on these approaches despite recurrence rates of 40%-60% with traditional colporrhaphy and up to 50% with paravaginal repairs.
For many years, these two theories about the etiology of anterior vaginal-wall prolapse and cystoceles seemed to me to be in disagreement with each other when it comes to inherent mechanisms of bladder prolapse and anterior vaginal-wall prolapse. I have wondered, what really causes bladder prolapse and why has recurrence of cystocele been the Achilles’ heel of pelvic reconstructive surgery?
In the past several decades, Dr. A.C. Richardson described several defects in the pubocervical fascia that he believed were associated with cystoceles. Later on in his career and life, he taught that bladder prolapse was the result of distinct detachments or site-specific defects in the support structures from the pericervical ring.
Reconstructing the pericervical ring and its attachments, he reasoned, would restore normal anatomy and repair bladder prolapse. Dr. Richardson’s later conclusions were never published, however, and midline plication and paravaginal repairs have remained the mainstays of bladder prolapse and anterior vaginal wall prolapse.
In the meantime, a firm understanding of exactly how vaginal birth affects the supportive structure of the bladder eluded us. It has long been believed that vaginal birth trauma contributes to the likelihood of symptomatic prolapse occurring, yet there was never any proof as to how and when the stress of vaginal birth causes pubocervical fascial injury. Nor was there any proof as to the location and direction of tears. Without accurately identifying specific damage patterns, one cannot recognize true defects that need to be repaired.
With the help of biomechanical engineers and biomechanical modeling, my colleagues at Atlanta’s Emory University and I found that the superior-to-inferior direction of the sheer stress and strain caused by both fetal descent and internal rotation of the fetal head causes tears in the pubocervical fascia that run in the transverse direction at the level of and from the pericervical ring – not vertically in the midline or laterally (paravaginally) as many had theorized.
Then, during cadaver dissections and surgical repairs of bladder prolapse, we identified the bladder protruding/herniating through the separation of the pubocervical fascia from the pericervical ring.
A true cystocele, we now know, is the result of a transverse defect that separates the pubocervical fascia from the pericervical ring. A paravaginal defect, on the other hand, can cause the anterior vaginal wall to prolapse, but it is not the cause of bladder prolapse. There is an important distinction to be made between these two entities.
Our approach to bladder prolapse, therefore, requires a transverse defect repair. We have developed a surgical technique that appears to successfully correct the defect by reattaching the pubocervical fascia to its original supportive structures, the pericervical ring, and the retroperitoneal uterosacral ligaments as they insert into the sacral peritoneum.