Pubovaginal Sling

Anatomy and Physiology

The four tissue layers comprising the female urethra help keep it closed. Resting urethral closure relies on the middle muscular and outer seromuscular layers in the female. The internal sphincter consists of the proximal urethra and bladder neck.[7] The external sphincter is responsible for both voluntary contraction and the involuntary guarding reflex during filling. For continence control, the pelvic diaphragm depends on the levator ani musculature. The pubocervical fascia and ureteropelvic ligament provide additional support. SUI could be a consequence of damage or injury to any of these supporting structures.  

SUI in females is proposed to be due to both intrinsic sphincter deficiency (ISD) and urethral hypermobility.[1] ISD results in incontinence because of decreased resting urethral closing pressure from urethral defects and inadequate sphincter coaptation. Urethral hypermobility results in incontinence when increased intra-abdominal pressure causes the anterior and posterior urethral walls to slide away from each other, opening the bladder neck.[1] The PVS is placed at the bladder neck and incorporates into the endopelvic fascia via fibrosis. This fixation provides adequate urethral coaptation during increases in intra-abdominal pressure.

Indications

Medical indications for pubovaginal sling placement include first-line treatment of SUI associated with urethral hypermobility or ISD and second-line treatment after a failed mid-urethral sling or colposuspension.[8]

Contraindications

As PVS placement is an elective procedure, relative contraindications for surgery include an active vaginal or urinary tract infection, pregnancy, uncontrolled diabetes, untreated bleeding disorders, and those at high risk for anesthetic complications due to compromised organ function.[9] Synthetic mesh slings are contraindicated in patients who are also concurrently having SUI surgery and repair of a urethrovaginal fistula, urethral diverticulectomy, or excision of eroded mesh.[8]

Equipment

There are currently multiple approved options for PVS. These include synthetic, autologous, xenograft, and allograft materials. The ideal implanted material incorporates into the host's tissue providing long-lasting suburethral support. Selection depends on both patient factors and surgeon experience. Synthetic and other biomaterials have become popular due to decreased operative time and post-operative recovery. However, autologous materials are the gold standard for PVS due to minimal inflammatory and foreign-body reactions.[6][10] The most common materials include rectus abdominis fascia and fascia lata.

A decision needs to be made preoperatively regarding which type of pubovaginal sling is going to be placed. The surgeon needs to make sure the hospital or surgical center has the product available if a synthetic, animal or human cadaveric sling is to be used.

Personnel

Pubovaginal sling placement can be performed by both urologists and gynecologists. It is recommended that the surgeon has an experienced assistant for optimal outcomes. Medical device sales representatives are often present in the operating room and can be very helpful in troubleshooting their particular products.[11]

Preparation

According to the most recent American Urological Association (AUA) guidelines published in 2017, initial evaluation of any woman presenting for surgical correction of SUI should include a focused history and physical exam with thorough pelvic examination, urinalysis, and assessment of postvoid residual urine volume. The focused history includes an assessment of bother which can be done via validated questionnaires. During the pelvic examination, the patient must be able to demonstrate SUI with a comfortably full bladder via a Valsalva stress test or cough.[10]

During informed consent, patients need to be counseled about the general risks of surgery and the specific complications of sling placement. Patient awareness of the potential dangers of synthetic mesh placement has increased due to increased media attention. Therefore, it is imperative to counsel women on the potentially serious complications, and the permanent nature of a synthetic mesh is being used for the procedure. After sling placement, the risks of voiding dysfunction must be discussed, including new-onset urgency, frequency, and urinary retention. 

The AUA best practice policy statement on antimicrobial prophylaxis published in 2019 recommends a single preoperative dose of 1st or 2nd generation cephalosporins for all urethral sling procedures.[12] Deep venous thrombosis prophylaxis for women undergoing incontinence surgery should be based on both patient and procedural risk factors.[13]

Technique or Treatment

After preoperative antibiotics are started, either spinal or general anesthesia is administered. The patient is then placed in dorsal lithotomy and carefully positioned to decrease the potential of lower extremity nerve injuries. Both the abdomen from the level of the umbilicus down as well as the vagina is then prepared and draped following sterile procedures.

If autologous fascia lata is being used, the knee on the harvest side is raised and supported while the leg is internally rotated at the hip and secured in stirrups.[14][15] The area is then prepared and draped following sterile procedures exposing the anterolateral thigh from the greater trochanter to the patella.[1][5] The proximal attachment at the greater trochanter and distal attachment at the lateral femoral condyle are marked. 

A regular 16-18 Fr Foley catheter is usually inserted into the urethra to drain the bladder. The patient, to obtain optimal visualization, is set in a moderate Trendelenburg position.[15] This is followed by placing a weighted speculum into the vagina, and labia majora are retracted with a vaginal ring retractor.[15]

To harvest rectus fascia harvest, it is taken above the pubic symphysis with caution taken to reduce injury to the ilioinguinal and iliohypogastric nerves. Dissection is carried down to the rectus fascia, where the graft is then marked out and harvested. The fascia is then closed in a running fashion with a PDS suture. To harvest fascia lata, the incision is made over the iliotibial band just above the patella and carried down to the fascia lata. The graft is then marked and harvested.[16]The thigh is then closed in three layers, and a compressive wrap is applied. After the fascia is cleaned off PDS suture is secured to each end of the graft. The autologous graft is then placed in the normal saline solution until needed.[17]

Injectable sterile saline is used to assist in the dissection of the vaginal epithelium before creating the flap. The vaginal tissue is hydrodissected by injecting the sterile saline into the vaginal epithelium at the mid-urethra and bladder neck. A retractor clamp is then placed below the meatus, and a midline vaginal or an inverted U-incision is then made approximately 2 cm below the urethral meatus to the level of the bladder neck with a scalpel. This incision provides both urethral exposures along with access to the endopelvic fascia and retropubic space.[15][17]

Once the incision is carried down through the vaginal epithelium, Metzenbaum scissors are used to create thick vaginal epithelial flaps, which are retracted with a retractor. The endopelvic fascia is then perforated in a superolateral direction with Metzenbaum scissors placed under the ischiopubic rami pointed towards the ipsilateral shoulder. The scissors are then opened widely and removed slowly to spread the fascia. The retropubic space is then fully opened using blunt finger dissection until the posterior pubic symphysis is easily palpated.[15][14][18][19]   

Suture passing needles are then placed behind the pubic symphysis from the abdominal incision. The needle is then advanced through the vaginal incision with simultaneous finger palpation of the device. Cystourethroscopy with a 70-degree lens is then performed to ensure the needles have not perforated the bladder. If this has occurred, the needles can be passed again with correct placement confirmed by cystoscopy. Ureteral patency is also confirmed by visualization of urine efflux bilaterally. The bladder is then drained after Foley catheter replacement.  

The sutures on both sides of the sling are then passed through the needle eyelets and brought out through the abdominal incision with the removal of the needles. The sling is then sutured in place to the periurethral tissue with two interrupted 4-0 Vicryl sutures. The vaginal incision is then closed in a running fashion with 2-0 Vicryl. The PDS suture is then loosely tied down while leaving a two-fingerbreadth space between the knot and the rectus fascia. The abdominal incision is then closed via the surgeon's preference.[20][21][22]

Complications

There has been a reduction in complications related to PVS due to technological advances. Chan et al. found a 19% PVS-related short-term complication that included but was not limited to urinary retention, wound infection, and intraoperative bladder laceration.[17] 

Other complications of PVS surgery include iatrogenic lower urinary tract or bowel perforation, significant hemorrhage, mesh exposure - erosion (urethra or bladder), implant infections, new-onset voiding dysfunction (urgency or bladder outlet obstruction), urinary retention, and UTIs.[23] 

While many complications are short-term and easy to resolve, a few, such as erosion and organ perforation, can be more difficult to treat, often requiring additional surgeries with increased morbidity.

Clinical Significance

The most critical benefit of PVS operation is that it averts incontinence by rebuilding urethral resistance during stress maneuvers. It also restores urethral coaptation or mucosal seal at which results in normal micturition.[6]

Enhancing Healthcare Team Outcomes

A collaboration among the clinical providers is critical.  We can enhance outcomes and performance if care coordination assists patients with recovery and support. PVS has been shown to have a long-term association with increasing the quality of life of SUI patients.[24] The long-term risk of undergoing surgery for SUI is 13.6%, but surgery has shown major improvement in the quality of life and productivity of the patients.[5]

Postoperative care is essential to manage the catheter starting at the hospital setting and to continue at the outpatient evaluation for post-void residual and voiding patterns. In general, team collaboration contributes to risk mitigation, better outcomes, and patient satisfaction.