Pelvic Floor Relaxation
April 5, 2009 Leave a comment
A rectocele is secondary to a defect in the supporting fascia of the rectum that results in a herniation of the anterior rectal and posterior vaginal wall into the lumen of the vagina. The true incidence of rectoceles is unknown. Wells et al. reported a 12% incidence of rectoceles on physical examination when evaluating patients complaining of urinary incontinence.Concomitant rectocele or enterocele repair was performed in 35% of patients undergoing a Raz bladder neck suspension; however, 65% of patients who underwent repair of a grade IV cystocele required rectocele repair.
To understand the concepts underlying repair of pelvic floor relaxation, the anatomy of the normal pelvic floor support system should be briefly reviewed. The pelvic diaphragm is the superior shelf of the pelvic floor and consists of the levator ani and the coccygeus muscles. The urogenital diaphragm forms the second layer of the pelvic floor and consists of the bulbocavernosus, transverse perinei, and external anal sphincter muscles. These muscles join together with the anterior fibers of the levator ani to form the central tendon of the perineum.
The fascial support of the rectum consists of the prerectal fascia and the pararectal fascia. The prerectal fascia runs anterior to the rectum from the pouch of Douglas to the central tendon and prevents protrusion of the rectum into the vagina. A virtual space exists between the posterior vaginal wall and the prerectal fascia, which offers a convenient plane of dissection during rectocele repair. The pararectal fascia originates from the lateral pelvic sidewall and sweeps posteromedially to the rectum, splitting into anterior and posterior sheets and forming a fibrous envelope around the rectum.
The normal vaginal axis that is seen in the well-supported pelvic floor conveniently protects against rectocele formation and further pelvic prolapse. Two distinct areas of the vagina are seen if a normal vaginal axis is maintained. The proximal vagina lies at a 110- to 120-degree angle to the horizontal. The distal vagina, with the sling-like support provided by the levators, forms an angle of 45 degrees from the vertical. This results in a midvaginal angle of 110 to 130 degrees. In women with significant pelvic floor prolapse, levator plate laxity and widening of the levator hiatus result in a disappearance of the normal curvature of the vagina and a near-vertical vaginal axis, which facilitates rectocele formation.
The high incidence of concomitant rectocele and cystocele relates to the pathophysiology of pelvic floor weakness and subsequent rectocele formation. Childbirth results in several events that weaken the pelvic floor support system: (a) passage of the child’s head through the vagina stretches the prerectal and pararectal fascia and detaches the prerectal fascia from the perineal body; (b) the levator musculature and its fascia are weakened, which allows the levator hiatus to widen; (c) the normal narrowing of the vaginal opening is rendered ineffective secondary to widening of the anogenital hiatus and damage to the UG diaphragm.
The changes wrought by childbirth are further enhanced by aging, loss of estrogen stimulation, obesity, smoking, strenuous work/physical activity, and chronic abdominal straining, which is often seen in patients with chronic respiratory diseases and cough, constipation, and bladder outlet obstruction. Furthermore, loss of the normal vaginal axis, which is seen with pelvic floor relaxation (and may be accentuated after cystocele repair and/or anti-incontinence surgery), results in ineffective transmission of intra-abdominal pressures. This may lead to a worsening of preexisting pelvic prolapse and an increased risk of stress incontinence. Defects of the perineal body are often a result of injuries sustained during vaginal delivery or episiotomy.
The majority of rectoceles are asymptomatic. If symptomatic, rectocele-related complaints are often related to bowel dysfunction and include constipation, the need to digitalize the vagina to facilitate stool passage, a feeling of blockage at the outlet, and a sensation of stool pocketing. Interestingly, although problems with constipation are often correlated with a rectocele, many patients report continued difficulties with constipation after rectocele repair. Patients may also complain of dyspareunia and symptoms attributable to prolapse such as the feeling of a bulge or sitting on a ball. Defects of the perineal body are usually asymptomatic, but patients may complain of incontinence of liquid stool or flatus or loss of sensation during sexual intercourse secondary to a widened introitus.
The diagnosis of a posterior wall defect is made on physical examination. Examination of the posterior compartment is best accomplished using a Sims retractor or half of the vaginal speculum to displace the anterior vaginal wall anteriorly. Perineal body defects are associated with a widened introitus and a decreased distance between the anus and the posterior aspect of the vagina and are graded as follows: I, a tear in the hymenal ring; II, a tear involving the perineal body but not the anal sphincter; III, a tear involving the anal sphincter; IV, a tear extending into the anal mucosa. A rectocele will manifest as a bulge extending from the posterior wall of the vagina and is graded as follows: I, protrusion of the posterior vaginal wall at the level of the hymenal ring; II, protrusion at the level of the hiatus; III, protrusion beyond the introitus. Rectoceles may further be classified according to their position in the vagina as low, medium, or high. Rectovaginal examination will reveal attenuation of the fascia and helps rule out coincidental enterocele, which should be suspected in the patient with a high rectocele. With posterior wall defects, loss of the normal banana-like axis of the lower and upper vagina is seen, as the vagina will assume a straight orientation. Finally, defecography and dynamic rectal radiologic examinations are used by some authors in the diagnosis and classification of posterior vaginal vault defects.
INDICATIONS FOR SURGERY
Patients with symptomatic posterior vaginal wall defects should undergo surgical correction. The repair of asymptomatic defects coincident with other vaginal surgery is controversial. Arguments against repair of an asymptomatic rectocele include postoperative coital dysfunction and rectal injury. Jeffcoate described a 30% rate of discontinued coitus or dyspareunia after anterior and posterior repair3; however, recent reviews evaluating outcomes using present-day techniques describe a 0% to 9% incidence of coital dysfunction. Rectal injury has not been a concern with current surgical techniques.
Arguments favoring repair of asymptomatic pelvic floor relaxation during concomitant vaginal surgery include the risk of larger and symptomatic pelvic prolapse (i.e., rectocele, enterocele, uterine prolapse) if repair is not accomplished and the possibility that results of simultaneous anti-incontinence surgery are improved if repair is done. Anti-incontinence procedures orient the vagina in a vertical axis; however, pelvic floor relaxation repair helps restore the normal near-horizontal axis of the vagina. Restoration of this axis decreases the incidence of postoperative prolapse, results in more effective transmission of intraabdominal pressure to the pelvis, and should improve the results of anti-incontinence surgery by helping to provide a strong backboard against which the bladder neck and urethra (which are secondarily supported by the pelvic floor) can be compressed. These arguments, combined with the ability to accomplish this surgery without introducing significant perioperative morbidity, leads us to strongly favor simultaneous repair of even asymptomatic moderate pelvic floor weakness at the time of concurrent vaginal procedures.
Alternatives to repair of pelvic floor relaxation include observation and intravaginal pessaries.
The essential goals of rectocele repair include (a) plication of the prerectal and pararectal fascia, (a) narrowing of the levator hiatus by reapproximating the prerectal levator fibers;) repair of the perineal body.
Two days before surgery, the patient begins a clear liquid diet and begins oral laxatives. Broad-spectrum intravenous antibiotics to cover anaerobes, gram-negative bacilli, and group D enterococcus are administered preoperatively.
Positioning and Retraction
The patient is placed in the dorsal lithotomy position, and a Betadine-soaked rectal packing is placed to aid in identification of the rectum and to avoid rectal injury. The patient is draped (the rectal packing is isolated from the operative field with double draping), and a Foley catheter is placed. Anti-incontinence surgery, cystocele repair, enterocele repair, and vaginal hysterectomy, if indicated, are accomplished first. A ring retractor with hooks, applied to the perineum, aids in lateral exposure of the vaginal vault. The anterior vaginal wall is retracted upward with a Haney or right-angle retractor to improve visualization and help prevent excessive narrowing of the vagina.
Exposure of Perineal Body
The rectocele repair begins with the placement of two Allis clamps to the posterior margin of the introitus at the 5- and 7-o’clock positions. A V-shaped incision is made, and a triangular segment of perineal skin with the base of the triangle at the mucocutaneous junction is excised between the Allis clamps, exposing the attenuated perineal body.
Exposure of Distal Vaginal Defect
The Allis clamps are then placed in the midline of the posterior vaginal wall, grasping and elevating the rectocele at its midpoint. Saline is injected along the posterior vaginal wall to facilitate dissection. With the use of a scalpel, a second triangular incision is made in the posterior vaginal wall with the base of the triangle at the site of the previous incision and the apex of the triangle above the levator plate 2 to 3 inches inside the hymenal ring. This is a superficial incision through the vaginal wall only; a deeper dissection at this point risks injury to the rectum. Metzenbaum scissors are then used to sharply develop a plane from the lateral margins of the triangle, dissecting between the herniated rectal wall and the vaginal wall. Staying as close as possible to the vaginal wall to avoid injury to the rectum, the dissection extends laterally, exposing the attenuated prerectal fascia distally. The triangular island of posterior vaginal wall that was created by the inverted V-shaped incision is sharply excised off the prerectal levator fascia and fibers. This redundant skin is not discarded until the rectocele is entirely repaired; if the repair is accidentally too tight and/or excessively narrows the vagina, the excised piece of vaginal wall may be used as a free graft.
Exposure of Proximal Vaginal Defect
The prerectal fascia is exposed by sliding the Metzenbaum scissors under the posterior vaginal wall from the apex of the previous triangular incision to the cuff of the vagina. The posterior vaginal wall is then incised along the midline. This incision is made from the apex of the previous triangular incision to the vaginal cuff. An appropriately sized rectangular strip of posterior vaginal wall is excised (a greater severity of prolapse necessitates a wider resection of posterior vaginal wall), exposing the attenuated pararectal and prerectal fascia proximally. Use of a Haney or right-angle retractor on the anterior vaginal wall at this point helps prevent resection of an excessive amount of posterior vaginal wall, thus decreasing the risk of vaginal stenosis postoperatively. Inadequate resection of sufficient vaginal wall risks a weak repair and the formation of painful ridges during reconstruction.
Plication of Prerectal and Pararectal Fascia
At this point attention is turned toward repair of the rectocele. The anterior vaginal wall is retracted upward, and the distal rectum is retracted downward with a Haney or right-angle retractor. This protects the rectum, reduces the rectocele, and facilitates reapproximation of the pararectal and prerectal fascia. Reconstruction begins at the apex of the rectocele and is carried out to the level of the levator hiatus with a running, locking 2-0 polyglycolic acid suture. Each needle passage incorporates the edge of the vaginal wall and generous bites of the prerectal fascia and the pararectal fascia bilaterally. We attempt to reapproximate the sacrouterine/cardinal ligament complex with the initial bite of this portion of the repair to decrease the risk of subsequent enterocele formation.
Repair of the Levator Hiatus
Two or three interrupted figure-of-eight 2-0 polyglycolic acid sutures are placed, closing the distal posterior vaginal wall to the level of the perineum. This suture incorporates the same layers as previously described. As the reconstruction continues, each side of the vaginal wall should proportionally come together such that the most distal aspect of the repair, at the mucocutaneous junction, is reapproximated evenly. Reapproximation of the prerectal levator fascia at this level restores the normal axis of the vagina. Therefore, examination of the repair at this point should reveal a well-supported posterior vaginal wall with a concavity (corresponding to the normal midvaginal axis of 110 degrees) to the repair proximally. Finally, a smooth contour without ridges should be noted along the suture line.
Repair of the Perineal Body
Several vertical mattress sutures of 2-0 polyglycolic acid are used to approximate the bulbocavernosus, transverse perineal, and external anal sphincter muscles. This brings together the muscles of the UG diaphragm, reconstructing and providing support to the central tendon. The perineal skin is closed with a running 4-0 polyglycolic acid suture, and an antibiotic-impregnated vaginal packing is placed.
This procedure is performed as an outpatient surgery. The Foley catheter and vaginal packing are removed several hours after surgery, and patients are prepared for discharge within 6 to 20 hours postoperatively. Patients are sent home with oral antibiotics and are maintained on stool softeners for 1 month. Finally, patients are encouraged to resume early postoperative coitus to ensure normal resumption of sexual function.
Urinary retention is the most frequent complication of rectocele repair and occurs in 12.5% of patients. Retention in these patients is temporary and rarely lasts more than several days. Rectovaginal fistula was not seen in our series but has been reported in up to 5% of patients undergoing pelvic floor repair. Dyspareunia can be averted by not excessively narrowing the vagina, avoiding suture placement directly into the levators, and by not leaving uneven, painful ridges along the repair. Other complications of vaginal surgery include infection, bleeding, vaginal shortening, vaginal wall inclusion cyst formation, and fistula.
Recurrent rectocele is very uncommon and has not occurred in any of the 95 patients we recently reviewed. However, recurrent pelvic prolapse can be expected in as many as 7.5% of patients postoperatively. Constipation is not resolved in up to 50% of patients undergoing rectocele repair for this complaint; this is likely a result of the multifactorial etiology of constipation in many patients.