Reconstruction of the Severely Damaged Female Urethra
January 17, 2010 Leave a comment
The severely damaged female urethra is a rare occurrence that has two main causes—obstetric injury and surgical trauma. Obstetric injuries are exceedingly uncommon in industrial countries but not so in the Third World. Damage to the trigone, vesical neck, and urethra during delivery is thought to be the result of prolonged and neglected labor, most often associated with maternal–fetal disproportion wherein the fetal head compresses these structures against the pubis, causing pressure necrosis. Surgical damage may occur during any of the Peyrera-type bladder neck suspension procedures, anterior colporrhaphy, urethral diverticulectomy, and, much less commonly, vaginal hysterectomy. In our experience, urethral diverticulectomy is the most common cause of extensive urethral damage. This most likely results from failure to obtain a tension-free closure of the urethral defect that results from excision of the diverticulum. During bladder neck suspension, inadvertent injury to the bladder or urethra may occur, or an errant suture may result in fistula formation or tissue necrosis. We have also seen several patients who sustained extensive tissue loss after a seemingly simple Kelly plication. It is postulated that the plication sutures were tied too tightly around a urethral catheter, resulting in pressure necrosis.
Rarely, indwelling urethral catheters may cause pressure necrosis of the urethra, and even more rarely, trauma to the pelvis may result in fracture or separation of the symphysis pubis, which lacerates the urethra and/or vesical neck. Finally, there may be local invasion of these tissues from carcinoma of the cervix or damage from radiation treatment.
Regardless of the cause of urethral damage, the diagnostic and therapeutic challenges to the surgeon are considerable. The goals of surgical correction are to create a continent urethra that permits the painless, unobstructed passage of urine and is of sufficient length to ensure that the patient does not void into the vagina. It is our belief that these goals can almost always be accomplished with a single operative procedure; only rarely is a staged procedure necessary.
Most patients with extensive damage to the urethra have overt incontinence; in them, the diagnosis is obvious upon examination of the vagina. Sometimes, though, when the vesical neck remains intact, there may be loss of the entire remaining portion of the urethra without any symptoms. These are generally discovered incidentally on physical examination and need no treatment.
With all of these injuries, one must have a high index of suspicion that there are concomitant abnormalities such as vesicovaginal or ureterovaginal fistula, ureteral obstruction, low bladder compliance, vesicoureteral reflux, and intrinsic sphincteric deficiency. A careful evaluation to exclude each of these potential conditions should be undertaken before surgery. In addition, detrusor function may be compromised in the form of impaired detrusor contractility or detrusor instability, but these conditions generally do not require evaluation unless they persist postoperatively.
We recommend that intravenous pyelography be performed in all patients except those in whom it is contraindicated. If there is any index of suspicion for ureteric injury, retrograde pyelography should be performed even in women with normal-appearing intravenous pyelograms. Cystoscopy and pelvic examination are essential in order to evaluate (a) the extent of the anatomic defect, (b) the possibility of unrecognized secondary fistulas, (c) the pliability of local tissue, (d) the need for securing bulk-ensuring tissue pedicle flaps, (e) the need for concomitant pelvic reconstructive surgery, and (f) the timing of surgery. Secondary vesicovaginal fistulas are usually apparent at cystoscopic examination. If a vesicovaginal fistula is suspected but not seen at the time of cystoscopy, the bladder should be filled with fluid to which a dye such as methylene blue has been added. The vagina should then be inspected for signs of urinary leakage with the urethra occluded with a Foley balloon catheter or with the surgeon’s examining finger occluding the urethra in order to prevent urethral leakage.
Urinary incontinence is not always caused by what appears to be the most overt lesion. For example, neither a urethrovaginal fistula nor a destroyed distal urethra should cause urinary incontinence unless the proximal urethra and vesical neck are also damaged. A careful stepwise evaluation should be carried out in all patients to delineate the pathophysiology underlying incontinence. Other causes of urinary incontinence commonly seen in these patients include (a) a previously undiagnosed vesicovaginal or ureterovaginal fistula, (b) detrusor instability, (c) low bladder compliance, and (d) sphincteric abnormalities.
INDICATIONS FOR SURGERY
The mere presence of extensive urethral damage is not an indication for surgery. The two main indications for reconstruction are sphincteric incontinence and urethral obstruction, but neither is absolute. Of course, if there is an associated condition such as a vesicovaginal fistula, it should be repaired at the same time.
Urethral reconstruction is technically demanding and requires a considerable degree of experience and skill. In inexperienced hands, the risks may be prohibitive, and in some instances, when there is insufficient local tissue for reconstruction, it may be more prudent to consider urinary diversion than urethral reconstruction.
When sphincteric incontinence is present preoperatively, we believe that it should be surgically corrected at the time of urethral reconstruction. In general, we prefer to construct a fascial pubovaginal sling3 with an interposed free graft of labial fat pa2,3 and 4,8 between the sling and the reconstructed vesical neck, but other authors have recommended the modified Peyrera technique in patients with less extensive anatomic damage and incontinence caused by urethral hypermobility.
Although it is important to document the presence of detrusor instability or low bladder compliance preoperatively, it has been our experience that after surgery these conditions abate in the vast majority of women. Accordingly, we do not recommend concomitant surgical interventions to treat these conditions at the time of urethral reconstruction.
There are three generic approaches to urethral reconstruction: (a) anterior bladder flaps (b) posterior bladder flaps, and (c) vaginal wall flaps. These techniques appear to be comparable with respect to creation of a neourethra. However, whenever the vesical neck and proximal urethra are involved, which is usually the case, postoperative incontinence rates of about 50% are to be expected unless a concomitant anti-incontinence procedure is performed.
We believe that vaginal reconstruction is considerably easier and faster, much more amenable to concomitant anti-incontinence surgery, and associated with much less morbidity than the bladder flap operations.
Alternatives to urethral reconstruction include various forms of urinary diversion and chronic catheter drainage. Chronic catheter drainage is indicated only in patients in whom there is no alternative, who are generally too ill to undergo any other procedure, and is associated with chronic infections, stones, and vesical spasms.
DESCRIPTION OF PROCEDURE
General Principles of the Surgical Technique
In these women, vaginal tissues are often scarred, fibrotic, and ischemic. Before surgery careful examination of the vagina is necessary to determine the actual extent of urethral tissue loss and to assess the availability of local tissue for use in the reconstruction. In most instances there is sufficient tissue in the anterior vaginal wall that can be mobilized and rolled into a tube or patch graft for urethral reconstruction. Occasionally, it may be necessary to use an adjacent labial flap. Alternatively, an anterior bladder flap can be used.
After reconstruction of the urethra or fistula repair, it is usually advisable to interpose a well-vascularized pedicle flap over the site of the repair. These include labial, rectus abdominis, and gracilis.
The most important surgical principles include (a) clear visualization and exposure of the operative site, (b) creation of a tension-free, multiple-layered closure, and (c) assurance of an adequate blood supply and (d) adequate bladder drainage. Operative exposure often requires two or more assistants and the use of self-retaining retractors. A tension-free closure can usually be accomplished by wide mobilization of surrounding tissue but sometimes requires the use of local pedicle flaps or relaxing incisions in the anterior vaginal wall. Bladder drainage is best accomplished with a large suprapubic catheter, which should be placed at the beginning of the procedure to avoid having to distend the bladder after the reconstruction.
Timing of Surgery and Preoperative Management
In the past, much controversy surrounded the timing of surgical repair. For decades it had been taught that surgery should be delayed for 3 to 6 months or longer to allow adequate time for tissue inflammation and edema to subside. In our experience, surgery can be safely performed as soon as the vaginal wound is free of infection and inflammation and the tissues are reasonably pliable. It is usually possible to perform the surgery within 3 to 6 weeks after the original surgery, but we have performed one reconstruction 7 days after birth trauma.
Management of incontinence while waiting for healing of the vaginal tissue is often a difficult problem. In most patients Foley catheter drainage is insufficient. If significant leakage occurs with a Foley catheter in place, we generally recommend that the catheter be discontinued and the patient be managed with superabsorbent pads, which are changed frequently throughout the day.
The patient is placed in the dorsal lithotomy position, and cystourethroscopy is performed to assess the relationship of the ureteral orifices to the damaged urethra. If the ureteral orifices are in close proximity to the fistula, single-J ureteral stents are left indwelling. A 16-Fr Foley catheter is inserted into the bladder, and the balloon is inflated with enough fluid to hold it securely at the vesical neck. A percutaneous suprapubic cystotomy tube (at least 14 Fr) is placed and sewn to the anterior abdominal wall unless a pubovaginal sling or modified Pereyra is planned, in which case this is deferred until the end of the procedure.
The choice of incision depends on the local anatomy of the tissue loss and whether or not a pubovaginal sling or other anti-incontinence procedure is planned. If a pubovaginal sling is planned, the dissection for the sling is completed first, and the sling is passed around the site of the vesical neck, but the sutures are not tied, and the sling is retracted so that it does not interfere with the subsequent dissection to reconstruct the urethra.
A Pfannenstiel incision is made and carried down to the rectus fascia. The surface of the rectus fascia is dissected free of subcutaneous tissue, and a suitable site is selected for excision of the fascial strip that will be used as a free graft for creation of the sling. Two parallel horizontal incisions 2 to 3 cm apart are made near the midline in the rectus fascia. The incisions are extended superolaterally for the entire width of the wound, following the direction of the fascial fibers. The undersurface of the fascia is freed from muscle and scar. Before the strip is excised, each end of the fascia is secured with a long 2-0 monofilament nonabsorbable suture using a running horizontal mattress, which is placed at right angles to the direction of the fascial fibers. No attempt is made to mobilize the bladder or vesical neck from above.
The lateral edges of the vaginal wound are grasped with Allis clamps and retracted laterally. The dissection continues just beneath the vaginal epithelium with Metzenbaum scissors pointed in the direction of the patient’s ipsilateral shoulder until the periosteum of the pubis or ischium is palpated with the tip of the scissor. During this part of the dissection, it is important to stay as far lateral as possible. This is best accomplished by dissecting with the concavity of the scissors pointing laterally and by exerting constant lateral pressure with the tips of the scissors against the undersurface of the vaginal epithelium. Once the periosteum is reached, the endopelvic fascia is perforated, and the retropubic space is entered. In most instances this is easily accomplished by blunt dissection with the surgeon’s index finger. The tip of the finger, opposite the nail, palpates the periosteum. With the back edge of the fingertip, the bladder and urethra are mobilized medially as the finger advances and perforates the fascia. This completely mobilizes the vesical neck and proximal urethra, freeing these structures from their vaginal attachments. In some instances this dissection must be performed sharply with Metzenbaum scissors.
The surgeon’s left index finger is reinserted in the vaginal wound, retracting the vesical neck and bladder medially. The tip of the finger is palpated by the right index finger, which is placed just under the inferior leaf of the rectus fascia. A long sharp curved clamp (DeBakey) is inserted into the incision and directed to the undersurface of the pubis. The tip of the clamp is pressed against the periosteum and directed toward the index finger, which is retracting the vesical neck and bladder medially. In this fashion, the clamp is guided into the vaginal wound. When the tip of the clamp is visible, one end of the long suture, which is attached to the fascial graft, is grasped and pulled into the abdominal wound. The procedure is repeated on the other side. A Kocher clamp is placed on the inferior edge of the rectus fascia, and the fascia is retracted vertically. An incision is made in the rectus fascia just above the pubis and lateral to the midline, just large enough to accept the sling. The long ends of the suture attached to the sling are grasped and pulled through the fascial incisions on either side. The rectus fascia is closed with a running suture of 2-0 PDS. The fascial sling is now positioned from the abdominal wall on one side around the undersurface of the vesical neck and back to the abdominal wall on the other side. The long sutures attached to either end of the sling are marked with clamps, and the sling is retracted out of the surgical field while the urethral reconstruction is being performed. At the conclusion of the operation, the long ends of the sling are tied together in the midline over the rectus fascia without any tension at all.
There are three basic techniques for urethral reconstruction:
1. Primary closure. If the anterior portion of the urethra is intact, it is usually possible to close the urethra primarily. The defect is circumscribed, and lateral vaginal wall flaps are elevated. If a pubovaginal sling is to be done, the dissection is completed at this time. The lateral urethral walls are mobilized, and the urethra is closed with interrupted sutures of 3-0 chromic catgut. We prefer chromic catgut to longer-acting synthetic absorbable sutures for urethral closure because, in our experience, the latter often make subsequent voiding and/or urethral instrumentation painful. If a Martius labial fat pad graft is needed, it is prepared at this time (see below) and placed over the reconstructed urethra and vesical neck. The pubovaginal sling is positioned over the Martius flap at the level of the bladder neck, and the vaginal incision is closed primarily with 2-0 chromic catgut.
Advancement flap. If there is insufficient tissue on the anterior vaginal wall at the site of the urethra to mobilize lateral flaps, it may be possible to repair the urethra and cover the repair with an advancement flap from the anterior vaginal wall cranial to the damaged urethra. A U incision is made in the anterior vaginal wall long enough to be advanced and rotated to form the posterior and lateral walls of a neourethra. The flap is mobilized with Metzenbaum scissors, reflected caudally, and sutured in place over the urethral catheter. When necessary, the dissection for a pubovaginal sling is done at this time before the vaginal wall flap is sutured. When indicated, a Martius flap is prepared and sutured in place between the reconstructed urethra and the pubovaginal sling. At the end of the procedure, the vaginal wall is closed primarily with 2-0 chromic catgut. If there is insufficient tissue for primary closure, it may be possible to use an inverted-U advancement flap or, rarely, a labial pedicle graft.
Tube graft. If there is circumferential loss of the urethra and sufficient vaginal wall tissue on the anterior vaginal wall, parallel incisions are made over the site of the neourethra, and the resulting strip is rolled into a tube over the urethral catheter. If there is a urethral fistula present, we prefer to retain the remaining bridge of urethral tissue and close the fistula to preserve local blood supply. The fistula is circumscribed, and an inverted-U-shaped incision is made. The flap is reflected caudally, and the dissection for the pubovaginal sling is completed. The fistula is closed by approximating its edges with interrupted sutures of 4-0 chromic catgut. Two parallel incisions are made on either side of the urethral catheter for construction of the neourethra. The flaps are mobilized, rolled into a tube over the urethral catheter, and sutured in the midline with interrupted sutures of 4-0 chromic catgut. A (Martius) labial fat pad graft is prepared to provide a second layer of tissue over the neourethra. The inverted-U flap is advanced over the entire reconstructed urethra. The vaginal and labial wounds are closed, and a ¼-inch Penrose drain is left in the labial wound. If it is not possible to close the vaginal incision primarily, a labia minora (hair-free) pedicle graft should suffice. Since we began using this technique, we have never found it necessary to use a gracilis myocutaneous graft.
The technique for creation of a Martius flap is as follows. A vertical incision is made over the labia majora, and the fat pad is mobilized. The fat pad is tunneled underneath the vaginal epithelium and sewn in place over the suture lines of the neourethra. If a single labial fat pad graft does not provide adequate coverage, a second graft may be obtained from the other side, or a gracilis, perineal, or rectus pedicle graft may be harvested. The pedicle graft is placed between the sling and the reconstructed urethra.
The Penrose drain is removed on the first postoperative day. The urethral wound is checked daily, and the catheter is removed as soon as feasible, usually within the first 2 to 5 days. A voiding cystourethrogram is performed though the suprapubic catheter at about day 14. If the patient voids satisfactorily and there is no extravasation, the suprapubic tube is removed. If not, the tube is left in place, and another voiding trial is undertaken 2 to 4 weeks postoperatively.
Bladder Flap Techniques
We believe that bladder flap reconstructions are almost never necessary in these patients, and the single patient in whom we performed this procedure was a failure. In the most recent and extensive series, Elkins et al.4 recently reported their experience with a Tanagho-like procedure in 20 West African women with extensive urethral damage subsequent to obstructed labor. These patients all had large vesicovaginal fistulas and, because of extensive scarring, were not suitable for vaginal flap techniques. The procedure was performed entirely through the vaginal approach.
The anterior and lateral fistula edges are dissected sharply away from the pubic bone beneath the arch of the pubic ramus, thus entering the retropubic space. The anterior bladder wall is dissected free of surrounding tissues to the level of the peritoneal re-flection.
The anterior bladder is mobilized, and a 3 × 3 cm flap is raised and rolled into a tube over a 16-Fr catheter. The new urethra is sutured either to the remaining distal urethra or at the site of the new meatus. The posterior edges of the vesicovaginal fistula are approximated, and fixation sutures are placed through the top portion of the neourethra to reattach the urethra to the base of the pubic periosteum. In the last three patients a modified Peyrera procedure was performed instead. A Martius fat pad graft was then placed beneath the suture lines.
Early in our series, we did not routinely perform concomitant pubovaginal slings, and 50% of the women who underwent a modified Pereyra procedure had persistent sphincteric incontinence; all were subsequently cured by a pubovaginal sling. Only one of the remaining women developed sphincteric incontinence, which was associated with necrosis of the reconstructed urethra. Three patients had flap necrosis, one a previously unrecognized vesicovaginal fistula, and one had urethral obstruction caused by the pubovaginal sling. All but one of the failures were subsequently reoperated on, and all had a successful outcome. This is consistent with the reported complications from large international series, where stress incontinence is a relatively frequent sequela of reconstruction and requires a second procedure.
In our series of patients who have undergone bladder flap reconstruction, 18 of the 20 women had a satisfactory anatomic repair of the fistula, but four of the 18 had persistent stress incontinence that required further surgery. Two others had refractory detrusor instability or low bladder compliance.
To date there has been a paucity of studies concerning reconstruction of the severely damaged urethra. Among all series we could find in the English language literature, there were fewer than 400 patients (Table 50-1). Overall, successful anatomic reconstructions were reported in 67% to 100% of women. Most authors emphasized the need for well-vascularized pedicle flaps to insure a successful outcome. Continence was achieved in only 55% to 92% after a single operation, and postoperative urethral obstruction was reported in 2% to 17%. In the great majority of studies, the criteria for incontinence and urethral obstruction were not specified, and especially in view of lack of follow-up, the results cited above should be considered optimistic ones. It does seem evident, however, that it is important to perform an anti-incontinence procedure at the same time as the urethral reconstruction. Failure to do so resulted in incontinence rates varying from 50% to 84%. Most series indicated that secondary procedures to correct incontinence are successful in the majority of patients.
The largest series was reported by Hamlin in 1969 from West Africa. All of the women suffered childbirth injuries, and all were quite extensive. An excellent anatomic repair was achieved in 49 of the 50 women, but eight (16%) had severe incontinence, and many more had lesser degrees of incontinence. They stated that the incontinence was usually cured after a second procedure.
Elkins et al.3 reviewed the results of 36 vesicovaginal and/or urethrovaginal fistula repairs performed by American visiting professors in West Africa. All of the vesical neck and urethral fistulas resulted from obstructed labor. In this series, two of 13 proximal urethral fistulas were complicated by severe stress urinary incontinence postoperatively.
To date we have operated on 51 women with extensive anatomic vesical neck and urethral defects caused by complications from urethral diverticulectomy, modified Pereyra bladder neck suspensions, anterior colporrhaphy (eight), and childbirth injury (one). All but one patient underwent a vaginal reconstruction (one patient had a Tanagho anterior bladder flap, and that failed). We used a Martius flap in all of the remaining patients except one who had a gracilis flap. We have previously published the results of 49 of these women.1 With the modifications described above, no patient required intermittent catheterization, and at least 1 year after their last surgery all were dry (except for the one woman who refused reoperation).
Reconstruction of the severely damaged urethra is a technically challenging undertaking and requires considerable surgical expertise and decision making. The vast majority of women with traumatic injuries have sufficient vaginal tissue for a vaginal flap reconstruction, and we believe that the vaginal approach offers the best chance for a successful outcome. However, in patients with extensive vaginal scarring from childbirth injuries, such as those reported by Elkins, bladder flap techniques may be useful.
The most important principles to keep in mind are: (a) clear visualization and exposure of the operative site, (b) creation of a tension-free, supple, multiple-layered closure, (c) assurance of an adequate blood supply and soft tissue base with a Martius flap, (d) concomitant pubovaginal sling when anti-incontinence surgery is indicated, and (e) adequate bladder drainage.