For many years, gynecologic surgeons awaited a primarily vaginal procedure that yielded cure rates and low complications comparable to the Burch colposuspension. The entire paradigm of surgery for stress urinary incontinence (SUI) underwent a significant change with the introduction of the retropubic tension-free vaginal tape (TVT) polypropylene mesh sling.1 This procedure is now the most commonly performed surgical treatment modality for SUI in women. The retropubic midurethral sling has also served as a prototype for a variety of modifications including transobturator tape slings, single-incision mini-slings, and adjustable slings. Objective cure rates vary depending on the definition of cure, but approximate 80% with follow-up times ranging from 1 to 11.5 years postoperation.2,3
Retropubic midurethral slings are indicated for primary or recurrent stress incontinence, for patients with intrinsic sphincter deficiency (ISD), for patients with or without urethral hypermobility, and for patients with stress-predominant mixed urinary incontinence.
The TVT retropubic procedure involves placing a 40 cm × 10 mm polypropylene mesh strip beneath the midurethra via a blind passage of a metal trocar through the retropubic space. The sling is covered by a plastic sheath that is removed after placement and final adjustment. The sling is placed loosely around the urethra without tension, making its initial attachment to the tissues by friction due to the design of the mesh. Cystoscopy is performed after each passage of the trocar to rule out unintentional perforation of the bladder or urethra. Bleeding in the retropubic space usually responds to external compression with or without use of local hemostatic agents. Some synthetic retropubic slings have dilators over the shaft of the trocar that allow a single cystoscopy to be performed after passage of bilateral trocars.
The primary indication for a retropubic midurethral sling is symptomatic stress incontinence. Patient symptoms alone have been shown to correlate poorly with the urodynamic diagnosis of stress or urgency urinary incontinence. Therefore, a multichannel urodynamic evaluation demonstrating involuntary loss of urine with increases in abdominal pressure in the absence of detrusor overactivity may be performed in patients prior to scheduling surgery as indicated. For patients with uncomplicated SUI without significant vaginal prolapse, a cough stress test may be all that is indicated.4 Patients with pelvic organ prolapse may not leak urine when prolapse is present due to the kinking effect on the urethra, particularly with a prolapsed bladder. Reduction of the prolapse during urodynamic testing may serve to unmask occult incontinence.
Patients should be advised that no anti-incontinence procedure is effective 100% of the time. By definition, midurethral slings should be tensioned loosely so as to avoid postoperation voiding dysfunction. Even with ideal placement, patients may experience transient incomplete bladder emptying requiring intermittent self-catheterization or an indwelling catheter. De novo detrusor overactivity is also seen in a small percentage of patients. Long-term urinary retention or incomplete bladder emptying is rare but does occasionally occur requiring sling revision and urethrolysis. Vaginal mesh exposure through the vaginal epithelium or erosion into the urethra may occur, particularly in patients with poor tissue estrogen effect. The treatment for mesh exposure may be management with intravaginal estrogen or surgical excision. Management of mesh erosion into the urethra or bladder is excision of the mesh and repair of the urethra or bladder as indicated. More serious potential complications include bothersome hemorrhage in the retropubic space, bladder perforation, bowel injury, and major vascular injury to iliac or obturator vessels.
In some centers, retropubic midurethral slings are performed as ambulatory procedures under local, often with conscious sedation, or general anesthesia. When local anesthesia is used, the patient can perform an intraoperative cough stress test to aid in placement of sling tension. Many patients in need of a sling for stress incontinence will also have associated pelvic organ prolapse or an indication for hysterectomy necessitating admission and general or regional anesthesia. Patient positioning is in the dorsal lithotomy position in Allen (Allen Medical Systems, Acton, MA) or candy cane stirrups to enable vaginal access. After surgical prepping and draping, an 18Fr Foley catheter is placed in the bladder left open to drainage.
Two 0.5 cm stab incisions are made 1 cm cephalad to the symphysis pubis, each incision 2 to 2.5 cm lateral to the midline.
Allis clamps are placed on the anterior vaginal wall along the ventral aspect of the urethra 1 and 2.5 cm proximal to the external urethral meatus. A vertical incision is made with the scalpel between the two Allis clamps. The Allis clamps are repositioned laterally on the edges of the vaginal mucosa. Using Metzenbaum scissors, while applying traction to the Allis clamps, submucosal tunnels are created bilaterally from the urethra upward and laterally toward the inferior aspect of the symphysis pubis aiming toward the ipsilateral shoulder (Figure 28-1). These tunnels will receive the TVT trocar and attached sling to allow passage from the ventral aspect of the urethra to the ipsilateral incision on the abdominal wall.
Box 28-1 Master Surgeon’s Corner
Ten ccs of dilute local anesthetic with epinephrine infiltrated into both right and left retropubic spaces helps deflect the bladder away from the symphysis prior to sling insertion and may decrease postoperative pain and risk for potential cystotomy.
A rigid catheter guide is placed in the 18Fr Foley and that is deflected ipsilateral to the placement of the sling arm. The trocar, attached to the nondisposable handle, is passed into the submucosal tunnel, being careful to guide the trocar along the back of the pubic bone and into the ipsilateral abdominal incision (Figure 28-2). The surgeon should take care to maintain an angle of the trocar and handle with the vertical axis of the patient such that the trocar is never more laterally directed than the patient’s ipsilateral shoulder in order to avoid serious vascular injury. The surgeon should control the direction of the trocar so as to avoid passage in a cephalad direction as opposed to moving the handle downward to pass the trocar directly behind the pubic bone (Figure 28-3). Such passage in a cephalad direction is more likely to result in bladder perforation.
FIGURE 28-2
Trocar passage. Trocar passage through the periurethral tunnel, perforating endopelvic connective tissue. The trocar is passed vertically through the space of Retzius, tracking along the posterior aspect of the pubic bone, through the abdominal incision. The index finger guides the trocar beneath the pubic ramus.
Following passage of the trocar, the catheter guide and Foley catheter are removed. A cystoscope with a 70° lens is inserted in the bladder. The bladder is distended with 300 to 400 mL of sterile water and a thorough inspection of the bladder is performed to rule out perforation. If a perforation is detected, the trocar should be removed under direct vision via cystoscopy, and the bladder observed for any serious bleeding. Most perforations are in the upper, lateral portion of the bladder and do not bleed excessively. After draining the bladder, the trocar may be replaced in a direction more toward the abdominal wall than cephalad.
If perforation of the urethra is suspected, cystoscopy with a 0° lens provides adequate visualization of the urethra. Removal of the device and repair of the urethrotomy should be performed.
If no bladder perforation is seen, the handle is detached from the trocar and the trocar is brought through the abdominal wall and tagged with a hemostat. The retropubic midurethral sling trocar is then placed on the contralateral side and cystoscopy is repeated taking care to perform surveillance of the entire bladder.
It is important to maintain the tension-free character of the retropubic midurethral sling by placing an instrument between the ventral aspect of the urethra and the sling and applying countertraction before removing the plastic sheaths (Figure 28-4). Some surgeons prefer to use a Mayo or Metzenbaum scissors for this purpose; others use a hemostat that is opened. Regardless of which instrument is used, the purpose is to create distance between the mesh and urethra and to avoid applying excessive tension as the sheaths are removed to lessen the probability of postoperative urinary retention.
The excess sling is trimmed and allowed to retract into the abdominal incisions. Closure of the abdominal incisions may be performed with 3-0 or 4-0 interrupted delayed absorbable sutures or with surgical adhesive. The vaginal incision may be closed with running locking 2-0 or 3-0 delayed absorbable suture. Some surgeons believe that it is important to use interrupted sutures for this closure to avoid mesh complications although there is not evidence to support this practice.
Before discharge from the hospital, a voiding trial should be performed. Following instillation of approximately 300 mL of sterile water (as tolerated by the patient) into the Foley catheter, it is recommended that the patient void roughly two-thirds of this volume (200 mL) before being considered for discharge home without an indwelling catheter or being taught intermittent self-catheterization. For those who do not empty the bladder satisfactorily in the hospital, a repeat voiding trial can be performed in an office setting in one to five days.
Patients should be advised to avoid strenuous activity, vigorous exercise, and constipation for at least eight weeks postoperation. Intercourse should be postponed at least four weeks or until the first postoperation office visit to insure that the vaginal incision has healed. Otherwise, normal daily activities, nonstrenuous exercise, and regular diet may be resumed during the first week following surgery.
The transobturator midurethral sling evolved as an alternative to the retropubic midurethral sling as a means to avoid unintentional bladder or bowel perforations resulting from blind passage of the trocar through the retropubic space. Instead, a polypropylene mesh strip is passed via a groin incision through the obturator foramen and passed beneath the urethra to create a less acute backboard than the U-shaped retropubic sling. Current studies indicate that short-term results in terms of objective cure rates for stress incontinence for transobturator midurethral sling procedures are not significantly different from cure rates obtained with retropubic midurethral slings.2,3
The primary indication for a transobturator sling is symptomatically bothersome SUI. Currently, it is unclear whether there is a difference in the effectiveness of transobturator slings in patients with intrinsic sphincter deficiency (ISD).
The transobturator procedure involves passage of a polypropylene mesh through a groin incision at the lateral margin of the pubic bone at the level of the insertion of the adductor longus muscle. Depending on the surgeon’s choice, available kits offer an outside-to-in passage of the trocar or an inside-to-out approach where the trocar is passed through a vaginal incision outward through the obturator fascia and muscle. Regardless of which approach is chosen, the procedure is designed to avoid passage through the retropubic space.
Patients with SUI should undergo multichannel urodynamic testing or cough stress test as indicated prior to any contemplated transobturator procedure. This will assist in assessing the presence of detrusor overactivity, marked Valsalva voiding, and those with large volumes of postvoid residual urine, thus allowing proactive management prior to undergoing the midurethral sling procedure for SUI.
As with all surgeries, patients should be advised of the risks of hemorrhage, infection, and the potential for voiding dysfunction that may occur with any type of sling surgery. Long-term voiding dysfunction with incomplete bladder emptying requiring intermittent self-catheterization or indwelling catheter drainage is rare but may occur. Success rates of approximately 80% at one to five years postoperation are reported but not all transobturator midurethral sling placements result in a successful outcome. Patient’s expectations should be discussed in detail prior to surgery to avoid misunderstanding in the postoperative period.
Vaginal mesh exposure through the vaginal epithelium or erosion into the urethra or bladder is rare but is more likely to occur in a patient with poor vaginal tissue estrogen effect. Preoperative administration of topical vaginal estrogen should be considered in patients with signs of marked vaginal atrophy. Although transobturator procedures are associated with a lower incidence of bladder perforation than retropubic procedures, the transobturator approach by no means insures against unintentional bladder entry. Postoperative groin pain and neurologic symptoms such as numbness have consistently been reported in patients post-transobturator sling procedures. Also, significant hemorrhage secondary to trocar injury to pelvic vessels has been reported.
The patient is placed in high dorsal lithotomy position in candy cane or Allen Acton, Massachusetts stirrups. After appropriate surgical prepping and draping, a 16Fr Foley catheter is placed in the bladder left open to drainage.
A 0.5 cm stab incision is made bilaterally at the lateral margin of the pubis, level with the clitoris and inferior to the adductor longus tendon insertion (Figure 28-5).
Box 28-2 Master Surgeon’s Corner
Handle of trocar should remain flat against surgeon’s hand. If handle rotates, then tip is deviated beyond points of safety.
A vertical incision is made in the anterior vaginal wall along the ventral aspect of the urethra that extends from 1 to 2.5 cm proximal to the external urethral meatus (Figure 28-5). The angle of the lateral groin incision relative to the suburethral incision is approximately 30° to 40° from the horizontal. Allis clamps are placed laterally on the edges of the vaginal mucosa and Metzenbaum scissors are used to develop bilateral submucosal tunnels on either side of the urethra in the direction of the ischiopubic rami.
Using the outside-to-in approach, the transobturator trocar is passed through one of the thigh incisions maintaining the tip in a cephalad direction until a series of “pops” are felt as the tip passes through the obturator externus muscle, membrane, and obturator internus muscle. The surgeon’s index finger is placed in the submucosal tunnel behind the ipsilateral pubic rami and, placing the tip of the trocar against the fingertip, the trocar is guided into the vagina (Figure 28-6). The end of the transobturator sling is attached to the end of the trocar and withdrawn through the thigh incision (Figure 28-7). The procedure is then repeated on the contralateral side.
The inside-to-out approach is essentially the reverse of the outside-to-in approach described above with the use of a winged guide to facilitate passage of the helical trocars through the obturator foramen.
An instrument, scissors, or open hemostat is placed between the ventral aspect of the urethra and the sling to act as a spacer to avoid applying excess tension during final sling placement. As the surgeon provides countertraction with the instrument, the assistant carefully removes the plastic sheaths. The excess sling is trimmed and allowed to retract into the thigh incisions.
Before closure of the vaginal and thigh incisions, cystoscopy should be performed to insure that no unintentional perforation of the bladder or urethra has occurred. Using a cystoscope with a 70° lens, a thorough inspection of the bladder should be performed. A 0° lens yields optimal visualization of the urethra. In the event of perforation of the bladder or urethra, the offending mesh should be removed, repair performed as indicated, and the sling replaced unless the extent of injury is prohibitive.
The vaginal incision should be thoroughly irrigated and closed with a running locking or interrupted 2-0 or 3-0 delayed absorbable suture. The groin incisions may be closed with surgical adhesive or with interrupted 3-0 or 4-0 delayed absorbable sutures.
Patients may be discharged on the day of surgery or kept in the hospital overnight depending on the level of postoperative pain and whether concurrent repairs were performed. A voiding trial should be performed before discharge. Patients with a postvoid residual volume of 100 mL or less following a 300 mL bladder fill may be discharged without need for further catheter drainage. Those with larger postvoid residual volumes should be taught intermittent self-catheterization or be discharged home with an indwelling Foley. A voiding trial can be performed in an outpatient setting in one to five days.
Strenuous activity, including aggressive exercise, excessively heavy lifting, and severe constipation, should be avoided for at least two months postoperation. Intercourse should be postponed at least four weeks or until the first postoperation office visit to insure that healing is proceeding normally.
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