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FUNCTIONAL: SLINGS FOR FEMALE SUI

See 2017 AUA Female SUI Guideline Notes

Female Stress Urinary Incontinence

Early theories regarding the cause of SUI were focused on the unequal transmission of pressure to the bladder and urethra, urethral hypermobility, and the abnormal inferior location of the urethra. Later theories (integral theory) emphasized the importance of 3 separate components that support the proximal and midurethra:
1. Pubourethral ligaments
2. Suburethral vaginal hammock
3. Pubococcygeus muscle

Injury to any of these components from surgery, parturition, aging, or hormonal deprivation can lead to impaired midurethral function and subsequently SUI

Intrinsic sphincter deficiency (ISD) is the primary underlying cause of SUI for women, with hypermobility being a secondary finding i.e. all women with SUI have some component of ISD, not all have hypermobility

Urethral hypermobility is a symptom of damage to the normal supporting structures of the urethra and not a cause of SUI
Maximum urethral closure pressures (MUCPs) < 20 cm H2O or abdominal leak point pressure (ALPP) < 60 cm H2O are indicative of ISD

In women who are continent, MUCP occurs at the midurethra
ALPP > 90 cm H2O signifies no or very little ISD

Urethral slings are currently the procedure of choice for the surgical correction of female stress urinary incontinence (SUI).

Preoperative Assessment

As per 2017 AUA Female SUI Guidelines, mandatory work-up of SUI includes (4):
1. History (including assessment of bother) and physical exam
2. Objective demonstration of SUI
3. Urinalysis
4. PVR
Urodynamic studies are not needed in all patients before SUI treatment
- Indications for urodynamics in SUI (9):
  1. Diagnosis of SUI remains unclear
  2. Negative stress test
  3. Concomitant overactive bladder (OAB) symptoms
  4. Possibility of neurogenic bladder
  5. Evidence of dysfunctional voiding
  6. Elevated PVR
  7. Grade ≥3 prolapse
  8. Prior lower urinary tract surgery
  9. An unexplained abnormality on urinalysis
  - If significant prolapse is present, UDS should be performed with and without a pessary
  - In patients with DO, treatment options other than sling surgery should be considered because stress-induced DO may be difficult to treat with a sling alone.
  - Abnormally small bladder capacity and decreased compliance may also negatively affect the outcomes of sling surgery, and these factors should also be considered.

Alternative Treatment Options

In most cases of incontinence, surgery should not be considered until more conservative management has failed.
- Initial conservative therapy includes:
  - Patient self-awareness and education
  - Dietary modification
  - Fluid restriction
  - Weight loss
  - Pelvic floor muscle training
The submucosal injection of periurethral bulking agents through a cystoscope into the urethra is a minimally invasive, mildly successful treatment for SUI.

Pubovaginal Slings (PVS)

Indicated for treatment of incontinence associated with a deficiency in a portion of the midurethral complex, hypermobility, ISD, MUI, concomitant cystoceles, urethral diverticula, and neurologic conditions
Anatomy and Mechanics of a PVS

Positioned at the bladder neck to provide urethral compression without obstruction during times of increased intraabdominal pressure.
The current concept of PVS comes from using a shorter free graft of rectus fascia whose tension could be adjusted

PVS Sling Materials

Autologous, allograft, xenograft, and synthetic materials have been used for the construction of a PVS
Although there is complete biocompatibility of the autologous sling and negligible urethral perforation, biologic graft and synthetic prosthetic materials have been increasingly used to decrease operative time, morbidity, pain, and hospital stay
Autologous fascia PVS

Gold standard for management of ALL forms of SUI
Advantages compared to alternative sling materials (2):
1. Minimal tissue inflammation
2. Negligible risk of urethral erosion
Disadvantages compared to alternative sling materials (2):

Increased operative time, hospital stay, postoperative pain, risk of suprapubic wound seroma, and risk of incisional hernia

Most commonly used autologous materials (2):
1. Rectus abdominis fascia harvested from the abdominal wall
2. Fascia lata harvested from the lateral thigh

Fascia lata is the preferred autologous material for PVSs in patients with a history of prior ventral hernia repair; unlike rectus facia, the recovery time is less and there is no risk of future abdominal hernia formation.
Disadvantages of fascia lata compared to rectus abdominis:
1. Requires repositioning of the patient
2. Increased operative time
3. Operating in an area unfamiliar to most pelvic surgeons

Improvement of SUI is similar with rectus abdominis fascia or fascia lata PVS

Allograft PVS

Were introduced in an effort to reduce overall morbidity, operative time, and pain related to graft procurement
Currently derived from either cadaveric fascia lata or acellular human dermis
Allografts from cadavers raise the concern of potentially transmitting illnesses such as HIV, hepatitis, and Creutzfeldt-Jakob prion disease
- The estimated risk of HIV transmission from an allograft is 1 in 1,667,600.
- The theoretical risk of developing Creutzfeldt-Jakob disease from a non-neural allograft is 1 in 3.5 million.
Tissue-processing techniques for allografts may disrupt the microstructure and affect their strength properties
- Maximum load to failure, maximum load/graft width, and stiffness are significantly lower for the allograft freeze-dried fascia lata group compared with the autologous, solvent-dehydrated, and dermal graft groups

Xenograft PVS

The forms of xenograft used are porcine dermis, porcine small intestinal submucosa, and bovine pericardium
Less tensile strength than allograft in situ and highest propensity to encapsulate

Synthetic PVS

The most commonly used synthetic material for PVSs is polypropylene mesh.
Advantages:

Almost unlimited supply of artificial graft material in various sizes and shapes, consistency in quality, elimination of harvest site complications, and decreased operative time.
More uniform, consistent, and durable compared with biologic grafts
Sterile, biocompatible, and noncarcinogenic
Lowest amount of degradation or disruption and the highest amount of fibroblast ingrowth and tissue ingrowth into the specimen

Disadvantages

Significant inflammatory and foreign body reactions
Higher rates of graft infection, urinary tract perforation, and vaginal exposure
- No longer used to due risk of complications

PVS Operative Procedure

Patient Counseling

If a synthetic prosthetic or biologic graft material is being used, surgeons should thoroughly counsel their patients about the permanent nature of these products and the unique and sometimes serious complications related to their use.
Patients should also be counseled about the risk of transient and permanent voiding dysfunction after surgery, including (2):
1. Postoperative difficulty emptying the bladder
2. De novo urgency and frequency

Graft Harvest for Autologous Pubovaginal Sling

Closure of the rectus fascia without tension is sometimes problematic. To prevent this difficulty, it is important to maintain a distance of ≥2 cm from the pubic symphysis
If undermining the fascial edges does not adequately mobilize the fascia, than interposition of a segment of synthetic mesh or graft may be necessary.

Pubovaginal Sling Vaginal Approach
Pubovaginal Sling Placement and Fixation

The bladder must be completely drained before passage of the Stamey needles to avoid inadvertent bladder injury
It is recommended to perform a cystoscopy after trocar passage to ensure integrity of the bladder and at the time of sling tensioning to visualize the bladder neck
A sling should never be tensioned before the weighted speculum is removed and the vaginal incision is closed. Tensioning before this may result in failure of the procedure due to too much or too little tension. The abdominal incision is closed after the sling is tensioned.
No suture fixation to the underlying periurethral fascia is necessary to anchor the sling

Pubovaginal Sling Postoperative Care

Outcomes of PVS for Predominantly SUI

No risk factors that consistently predict outcomes
PVS are particularly helpful in treating ISD
The reported cure rate of PVS surgery for recurrent SUI is excellent
Autologous PVS

Continence rate after PVS ranges from 61-97%; wide range due to variation in outcome definition
Postoperative de novo or urgency incontinence rates range from 2-21%

Most common reason for failure/patient dissatisfaction relates to urgency symptoms and urgency incontinence at follow-up

Allograft PVS

Limited outcome data, and the efficacy and durability of these slings are questionable
Previously reported failures coupled with the consistent success and rapid adoption of synthetic MUSs has led to abandonment of all types of cadaveric allograft at most centers.

Xenograft PVS

Because of the morbidity of autologous fascial harvest, high failure rates of allograft materials, and high exposure and perforation rates with synthetic PVSs, xenografts are an attractive option.
In general, they are associated with a low rate of infection, exposure, and perforation owing to their incorporation into host tissue cure rates comparable to those of the autologous sling.
In RCTs, porcine dermis was associated with significantly inferior long-term cure rates compared with the autologous PVS

Outcomes of Autologous PVS for Mixed Urinary Incontinence

Overall, PVS remains an effective treatment option for MUI with cure rates similar to those of simple SUI.
- The treatment of patients with mixed urgency and SUI is complicated and often involves a combination of anticholinergic therapy and surgery
- PVS is an effective treatment option for stress-induced DO with cure rates similar to those of simple DO.
- Anti-incontinence surgery may cure or aggravate urgency symptoms or lead to de novo urgency. This aspect of anti-incontinence surgery is unpredictable and a major cause of patient dissatisfaction
- The presence of residual urgency is similar to de novo urgency with a PVS.

Outcomes of Autologous PVS for Urethral Reconstruction

Autologous PVSs in the setting of urethral reconstruction (urethral fistula, urethral diverticulum, destroyed urethra) has excellent results when compared with other surgeries for incontinence

Voiding Dysfunction Secondary to Bladder Outlet Obstruction after PVS

PVS is associated with higher success rate but increased risk of post-operative voiding dysfunction compared to the Burch colposuspension

SISTEr trial

655 women with SUI
Randomized to autologous rectus fascia PVS vs. Burch colposuspension
Results

Success rates higher for PVS
Voiding dysfunction (63% vs. 47%, P < .001), UTI, difficulty voiding, and postoperative urgency incontinence higher for PVS

The presentation of patients with obstruction by a PVS is variable and the symptoms range from complete urinary retention, impaired detrusor, detrusor overactivity contractility and urgency incontinence to the less obvious irritative symptoms.

Persistent/increasing urgency incontinence and urgency (8-25%) are more common presenting symptoms in bladder outlet obstruction after a PVS procedure than frank retention
The incidence of permanent retention is usually ≤ 5%; the majority of patients who require clean intermittent catheterization after PVS placement had a neurogenic bladder preoperatively

There are no well-established risk factors for patients who are likely to experience voiding dysfunction after PVS surgery. Although urodynamic studies are useful in understanding the voiding dynamics of incontinent women, low detrusor pressure and Valsalva voiding preoperatively should not exclude patients from having an anti-incontinence procedure.
Although postoperative urgency and urgency incontinence (voiding dysfunction) are strongly related to failure, there are no preoperative risk factors that consistently predict these outcomes after PVS surgery.
Cystoscopy is useful to rule out bladder pathology, sling perforation, and a hypersuspended urethra.
The most important criterion for a sling incision or urethrolysis remains the temporal relationship between the symptoms and the surgical procedure. Urodynamic studies are essential in these cases to diagnose and make an appropriate treatment plan.
A key factor in assessing voiding dysfunction is the presence of prolapse that was either uncorrected at time of surgery or that occurred postoperatively. Prolapse of sufficient size may kink or angulate and externally compress the urethra. After surgery, apical, anterior, and posterior prolapse must be ruled out as a cause of the urethral obstruction.
Surgical Management of Voiding Dysfunction after PVS

See 2017 AUA Female SUI Guidelines Notes
Obstruction after an autologous PVS procedure usually improves or resolves with time; although transient urinary retention is common, most patients return to spontaneous voiding within the first 10 days
In the first 6 weeks after autologous PVS surgery, loosening the sling in the operating room (using spinal or general anesthesia) can be attempted. This is done by first inserting a cystoscope into the bladder and then gently applying caudal pressure to the urethra. This procedure is not advised with synthetic slings
After 6 weeks or when conservative measures fail, a formal urethrolysis by a retropubic, transvaginal, or suprameatal approach or sling incision is indicated.

Sling incision has comparable success rates and shorter operative time and less morbidity than formal urethrolysis
Reported success rates of the surgical management of bladder outlet obstruction after a PVS procedure are 65-93%
Recurrent SUI after formal urethrolysis is reported as 0-19% and 34% after sling incision

There are no preoperative or urodynamic parameters that consistently predict success or failure of urethrolysis.
Failure of urethrolysis may be caused by persistent or recurrent obstruction, DO, impaired detrusor contractility, or learned voiding dysfunction. The most common reason for failure is likely insufficient dissection and lysis of the urethra. This supports the use of repeat urethrolysis in the face of initial failure or in cases wherein the aggressiveness of the initial dissection is unknown.
OAB symptoms are refractory in 50% of affected patients after urethrolysis and contribute to a significant portion of the reported failures. Refractory storage symptoms after urethrolysis can be challenging to treat. In addition to anticholinergics, SNM should be considered as an option for de novo or refractory urgency and urgency incontinence after urethrolysis.

Complications of Pubovaginal Slings

Mesh located in the lower urinary tract is termed a perforation, and extrusion of mesh through the skin or vagina is termed exposure
Pubovaginal Sling Perforation and Exposure

The incidence of PVS perforation and exposure is partially dependent on the composition of sling material.
- Synthetic slings perforate 15x more often into the urethra and are exposed 14x more often in the vagina than autologous, allograft, and xenograft slings. The perforation or exposure of autologous PVSs is rare
  - Urethral perforation rate was 0.02% and the vaginal exposure rate was 0.007% in 1515 patients who received synthetic slings.
  - Urethral perforation incidence of 0.003% and a vaginal exposure incidence of 0.0001% in 1715 patients undergoing autologous and allograft sling procedures.
Urethral perforations present at ≈9 months
Presenting symptoms often include urinary retention, urgency, and mixed incontinence. In addition, synthetic sling perforations and exposures are also associated with vaginal discharge, vaginal pain, suprapubic pain, and recurrent UTIs.
Management of autologous and allograft PVS urethral perforation usually involves incision or excision of the part of the sling that has perforated and simple closure of the urethra
The incidence of recurrent SUI after synthetic PVS urethral perforation is 44-100%, and treatment often involves a second PVS
Because urinary tract perforation and vaginal exposure of synthetic PVSs are more common and associated with significant morbidity, synthetic material is no longer used for bladder neck slings

Non-urologic Complications of PVS

Most commonly pulmonary, cardiovascular, neurologic, and gastrointestinal (bowel injury)

Pubovaginal slings (PVS) are placed under mild tension at the bladder neck to reestablish the suburethral hammock and are able to improve SUI by providing a layer of tissue that compresses the urethra during times of increased intra-abdominal pressure.
Unlike the PVS, the MUS should be placed loosely at the midportion of the urethra to prevent movement of the posterior urethral wall

Midurethral Slings (MUS)

Retropubic and transobturator MUSs are equally efficacious and generally safe
Mechanics, Anatomy, and Materials of Midurethral Slings
- Mechanics of the Midurethral Sling
  - MUS works by impeding the movement of the posterior urethral wall above the sling, directing its motion in an anteroinferior or anterior direction. In addition, inward movement of the posterior urethral wall after placement of a MUS results in urethral lumen narrowing (compression).
  - Ideally placed loosely at the midurethra
  - Overall, patients without urethral hypermobility do not respond as well to MUS surgery.
    - Lack of urethral mobility is an indication that the patient has a fixed urethra and ISD.
  - A loosely placed MUS combined with a mobile urethra may allow the sling to compress the urethra during times of Valsalva and stress while remaining nonobstructive when the urethra is at rest.
  - Types: retropubic, transobturator, and single-incision
    - Unlike retropubic and transobturator MUSs, for single-incision MUSs it appears that restriction of urethral mobility after surgery is associated with a better outcome
Anatomy of the Retropubic Midurethral Sling

The left and right dorsal nerves of the clitoris (DNCs) run along the inferior surface of the ischiopubic rami and cross under the pubic bone approximately 1.4 cm from the midline
The obturator vessels are the closest major vascular structures to a retropubic MUS

Anatomy of the Transobturator Midurethral Sling

The transobturator technique is unique because (when done correctly) it avoids entry into the true pelvis and the levator group.
- Muscle’s traversed by this technique include the obturator internus muscle, obturator membrane, and obturator externus muscle as it goes through the obturator foramen, and the adductor muscles (adductor magnus, adductor brevis, and gracilis), lateral to the obturator foramen
  - Errant sling placement through the adductor longus tendon can result in substantial pain.
The obturator vessels are lateral and superior to the area of insertion of the device.
The dorsal nerve of the clitoris is separated from the trajectory of the device by ≥1-2 cm

Anatomy of the Single-Incision Midurethral Slings
Midurethral Sling Materials

The initial MUSs were made of materials with smaller pore sizes
Currently, a soft, loosely woven, polypropylene monofilament mesh with a pore size > 75 μm is the most commonly used material

Midurethral Sling Operative Procedures

Patient Counseling

Because MUS surgery involves the implantation of a synthetic, prosthetic material, surgeons should thoroughly counsel their patients about the permanent nature of these products and the unique and sometimes serious complications related to their use. Also, similar to the PVS, patients should also be counseled about the risk of transient and permanent voiding dysfunction after surgery. This should include a discussion of postoperative difficulty emptying the bladder and de novo urgency and frequency.

Anesthesia, Patient Positioning, and Preparation Surgical Approach for Retropubic Midurethral Slings

Cystoscopy is performed to exclude trocar penetration of the lower urinary tract.
If bladder perforation is noted, the trocar is withdrawn and passed once more with an effort to avoid further perforation.
In general, a MUS should be placed loosely at the midurethra because its function is not primarily related to compression.

Surgical Approach for Transobturator out-to-in Slings
Surgical Approach for Transobturator in-to-out Slings
Surgical Approach for Single-Incision Slings

Tension of single-incision MUSs should be tighter than the classic retropubic or transobturator MUS surgeries to achieve the same result

Outcomes of MUS for Predominantly SUI

Outcomes of transobturator MUS procedures in patients with predominantly SUI are similar to those of the retropubic MUS, regardless of urethral function
5-year results demonstrate durability similar to 1-year results

Outcomes for Single-Incision MUS in Patients with Predominantly SUI

There are fewer data available regarding the safety and efficacy of this new generation of slings compared with the retropubic and transobturator MUSs.
Single-incision slings have decreasing efficacy with longer follow-up.

Outcomes of MUS for MUI

Results with mixed incontinence are acceptable compared with other types of interventions for urinary incontinence but are less than those obtained in pure SUI.

Outcomes of MUS for Intrinsic Sphincteric Deficiency

The success of MUSs is lower in patients with ISD/fixed urethra (no urethral mobility) and low leak point pressures

Fixed urethras have poor outcomes after MUS surgery regardless of leak point pressure
Retropubic MUS are more effective than transobturator MUS in patients with ISD

Low leak point pressures are not necessarily a contraindication to retropubic MUS surgery
MUS is beneficial in the management of SUI in patients with ISD as long as there is preoperative urethral mobility; urethral mobility before MUS procedures has been shown to be predictive of success; the more the proximal urethra moves during a Valsalva maneuver, the better the cure rate for incontinence

Outcomes of MUS in Patients with Pelvic Organ Prolapse

Results suggest that the MUS can be added to prolapse surgery with minimal morbidity.

The Cochrane Incontinence Group reviewed 22 randomized trials of surgical prolapse repair including 2368 women. They concluded that the addition of a retropubic MUS to endopelvic fascial plication, Burch colposuspension, and abdominal sacrocolpopexy may reduce the incidence of postoperative SUI, but issues of cost and associated adverse effects were unclear
Women who underwent prolapse repair at the time of the sling surgery were significantly more likely to be diagnosed with postoperative outlet obstruction (9.4% vs. 5.5%, P < .007), but less likely to undergo a repeat procedure for stress incontinence or reoperation for prolapse within 1 year after sling surgery.
When MUSs are placed for urodynamic or occult SUI at time of prolapse repair, the risk of intervention because of obstruction is equivalent to the risk of intervention for SUI if no MUS was placed (8.5% and 8.3%, respectively)

MUSs placed with either transvaginal or laparoscopic-assisted vaginal hysterectomy and anterior or posterior colporrhaphy have been shown to have success rates similar to those in published series of MUS surgery alone. Complication rates are also in accordance with other MUS series

Outcomes of MUS in Elderly Patients

Cure rates in older women with urethral hypermobility are comparable to those in younger women.
- Elderly women should not be excluded from potentially curative MUS surgery based on their age alone.
- Mixed urinary incontinence resolution rates are similar to those of the younger population
- Possibly because of preoperative factors such as MUI or even decreased urethral hypermobility, the rate of persistent SUI after retropubic or transobturator MUS procedures appears higher in the elderly population [different than above?].
Complication rates vary, with some studies citing a higher rate of age-related morbidities but no apparent increase in intraoperative complications.
- Elderly patients experience higher rates of postoperative de novo urgency and urgency incontinence associated with any sling material, including MUS

Postoperative retention occurs to a similar degree as in younger patients

Outcomes of MUS in Obese Patients

Whether obesity affects surgical outcome with MUSs is controversial.
Overall, the rate of complications appears to be similar in obese versus non-obese patients undergoing MUS surgery.
- Higher rate of bladder trocar injury in non-obese patients

Efficacy and safety of MUSs are not compromised in the elderly, the obese, or those undergoing concomitant vaginal surgery.
Outcomes of MUS for Recurrent Stress Urinary Incontinence
- As salvage procedures, MUS have overall efficacy similar to their use in primary implantation procedures.
- The procedure can be performed in the same way as it is performed for primary SUI.
- The complication rate is similar to that of retropubic MUSs done for primary SUI, but the risk of bladder perforation appears to be higher in females who have had ≥1 prior retropubic suspensions.
- As is the case with primary surgery, the failure rate is higher in females with immobile urethras.
- No significant difference in subjective cure rates in patients after retropubic vs. transobturator MUS surgery for recurrent SUI.
Complications of Midurethral Slings

Overall, the rate of complications associated with the MUS procedure is relatively low.
The rates of:
1. Bladder trocar injury: 2.7-3.8%; higher with retropubic
2. Voiding dysfunction: 7.6%
3. Wound healing problems: 1%
4. Vaginal mesh exposure: 0.5-8.1%
5. Mesh perforation of urethra (transobturator and retropubic): 0-0.6%
6. Mesh perforation of bladder: 0.5-0.6%
7. Sexual dysfunction
8. Groin pain; higher with transobturator; conservative therapy with NSAIDs should resolve the majority of symptoms. If pain persists after 6-8 weeks, consider referral to a pain clinic for trigger point injections and physical therapy.
9. Bleeding, vascular injury; higher with retropubic
10. Infection, bowel perforation, and death
The exact cause of these complications is debatable, but they likely arise from a combination of patient and technical factors.
- Factors include patient body habitus, subclinical infection, poor tissue ingrowth into the sling, disturbed wound healing, rolling or twisting of the sling, excessive friction between host tissue and the sling, sling material properties, and iatrogenic injury and surgeon technical error.
- Biomechanical properties of the sling material have also been shown to play a major role in the incidence of complications related to mesh exposure. Although various materials have been historically used for sling implants, there has been a trend in the contemporary literature toward the use of macroporous polypropylene slings. The increased pore size of these materials allows for: excellent tissue ingrowth, promotes integration with the surrounding host tissues, and decreases encapsulation and infection
MUS Bladder Trocar Injury

Rate of trocar injury is higher with retropubic vs. trans-obturator MUS

The rate of bladder or urethral trocar injury:

Retropubic MUS surgery: 2.7-23.8%
Trans-obturator MUS surgery: 0-1.3%

Trocar injury is generally thought of as a benign condition. If occurs intra-operatively, remove trocar and pass trocar again more laterally and leave foley catheter in 3-7 days.

MUS Mesh Exposure

Most cases manifest within a few weeks to a few months after the MUS procedure
Symptoms of vaginal exposure include:
1. Vaginal discharge (with variable constituents and different amounts of blood and inflammatory components)
2. Palpable rough surface in the vagina
3. Sexual discomfort (including partner related)
4. Pelvic pain
5. Inguinal discomfort
6. LUTS (urgency, frequency, persistent incontinence, hematuria)
The management of this complication is not standardized, composition of mesh is particularly important in the event of mesh exposure
Management

Conservative management is an option in well-selected patients who are relatively asymptomatic and have small-caliber exposures (<1 cm)
The next step involves addition of conjugated estrogen and possibly antibiotic creams
Excision should be reserved for failure of conservative therapy or when local symptoms mitigate against observational management (e.g., bothersome dyspareunia). Limited excision and trimming with vaginal closure can be attempted. Even with partial excision of the mesh, continence is maintained in the majority of patients.
If these options fail, excision of most of the mesh from a transvaginal approach should be pursued in most cases.

Operative management typically involves excision of the exposed mesh, thorough irrigation with antibiotic solution, and closure of vaginal flaps. Good results have also been observed in selected patients with vaginal advancement flaps and suture approximation of the debrided vaginal mucosa over the exposed mesh.

MUS Mesh Perforation of the Urethra

Presenting symptoms are variable, voiding dysfunction is predominant
Management

Management of this complication is extremely challenging
Observation should never be considered when there is urethral perforation
Although we prefer transvaginal surgical excision as a first-line treatment, endoscopic management of small areas of mesh perforation appears to be a reasonable initial option
For slings that perforate into the urethra an inverted-U incision is best because this allows for exposure of the proximal urethra, bladder neck, and endopelvic fascia as well as providing a vaginal epithelial flap that avoids overlapping suture lines
An autologous fascial sling or a Martius labial fat pad graft can be used, at the discretion of the surgeon.
An autologous fascial sling can be placed at the time of surgery to augment the repair or in a delayed fashion to treat recurrent SUI.

MUS Mesh Perforation of the Bladder

The majority of intravesical mesh perforations are most likely the result of an unrecognized cystotomy or placement of the mesh within the urinary bladder at the time of surgery.
Typical symptoms are lower abdominal pain, intermittent gross hematuria, recurrent UTI, urgency, frequency, dysuria, and urinary incontinence.
Management of MUS Mesh Perforation of the Bladder

Observation should never be considered when there is intravesical perforation
For small areas of mesh perforation, endoscopic excision with scissors or ablation with the holmium laser as an appropriate initial step, although this is contingent on absolute excision of all exposed material
After endoscopic excision fails or as an initial treatment, mesh perforated into the bladder can be removed from a transvaginal or retropubic approach.
Reconstruction should involve nonoverlapping suture lines and interposition of tissue such as a labial fat pad or greater omentum.
An autologous fascial sling can be placed at the time of surgery to augment the repair or in a delayed fashion to treat recurrent SUI.

Pain and Infection after MUS Surgery

Groin and suprapubic pain are potential problems after MUS placement. Thigh and groin pain appear to be more commonly associated with the transobturator approach
- Most groin pain resolves after the second postoperative day.
  - Pain persists longer after the transobturator midurethral slings.
Severe infection is a rare complication after MUS surgery, and the diagnosis of this complication is variable and can take as long as several years

Obesity, diabetes, and hypertension are associated with fasciitis after pelvic surgery.

Management of MUS Severe Infection or Pain.

In most cases, postoperative groin or leg pain after MUS surgery can be managed with NSAIDs, rest, and physical therapy. Most groin pain resolves after postoperative day 2
In instances of chronic mesh pain and severe infection when nonoperative therapy has failed, it may be necessary to attempt a complete mesh excision from both sides of the bone.
For the complete excision of transobturator mesh we typically consult an orthopedic surgeon to aid with lateral dissection of the sling.

Voiding Dysfunction after MUS Surgery

Voiding dysfunction after MUS is substantially less than with PVS (bladder neck) slings but still occurs
Usually transient, long-term urinary retention and obstructive voiding dysfunction are rare after the MUS procedure
Typically the result of obstruction from the sling as a consequence of the sling being placed too tightly or in the wrong location (too proximally) or associated with pelvic organ prolapse (unrecognized preoperatively or de novo); however, some patients may have voiding dysfunction without evidence of obstruction
In general, the rates of de novo urgency and perioperative urinary retention are similar among the different types of MUSs. The most common symptoms of obstruction are an inability to void (urinary retention), incomplete emptying, and de novo urgency and frequency. Over several weeks to a month, the irritative voiding symptoms (urgency, frequency, and pain) become more prevalent as the bladder attempts to adjust to the obstruction.

De novo urgency occurs with postoperative voiding dysfunction in as many as 12% of patients
However, a recent RCT found significantly higher rate of voiding dysfunction necessitating surgery (or permanent catheter) after a retropubic MUS compared with a transobturator sling procedure (2.7% vs. 0%).
In addition, the rate of urinary retention (catheter for longer than 6 weeks) was also higher in the retropubic MUS group (3.7% vs. 0.7%).

There does not appear to be a consensus in the literature regarding preoperative factors that contribute to voiding dysfunction after MUS surgery.
The optimal evaluation for patients with postoperative voiding dysfunction is poorly defined in the literature. The decision to perform urethrolysis is usually based on a clear temporal relationship between onset of symptoms and the surgical procedure.
Cystoscopy is useful to rule out bladder pathology, urethral mesh perforation, and a hypersuspended bladder neck.
Management of Voiding Dysfunction after Midurethral Sling Surgery

Urinary obstruction after MUS surgery is usually transient and can be managed with short-term intermittent catheterization
For patients with persistently elevated residual urine and bothersome symptoms refractory to conservative management, transvaginal sling release procedures consistently provide resolution of symptoms with maintenance of continence in the majority of patients

Urethral dilation is of limited usefulness and, if used too aggressively, may be detrimental.
Cutting the MUS in the midline through a single vertical vaginal incision using minimal dissection is the preferred method to manage persistent voiding dysfunction that results from an obstructive sling within the first 3 months after surgery; the entire sling does not need to be excised

The exact timing of sling incision is variable; however, most recommend waiting at least 2 weeks; the sling should be incised within 4 weeks of surgery
The majority of patients maintain continence with single incision

After 3 months, the sling may be fixed along its entire course, and midline sling incision may not achieve enough sling relaxation to resolve voiding dysfunction. In these cases, we perform a more formal sling excision and urethrolysis

Sexual Dysfunction after MUS

Contradictory evidence in the literature that MUS surgery improves and worsens sexual function

Some attribute improved sexual function after MUS surgery to a significant decrease in coital incontinence
The rate of de novo dyspareunia after MUS surgery is between 3-14%; sling removal can improve dyspareunia

Other Complications after MUS Surgery

Infection, bleeding, vascular injury, bowel perforation, and death.

Risk of major vascular injury higher with retropubic vs. transobturator
The majority of postoperative hematomas resolve without intervention

UTI is the most common and easily treatable complication of MUS surgery.

Regulatory and Legal Issues Related to Sling Mesh Complications

See CUA/AUA Mesh Position Statements
The success of MUSs for incontinence led to the development of mesh products for pelvic organ prolapse repair. However, while the use of mesh during pelvic organ prolapse repairs has increased, so too have complications related to its use.
In October 2008, the FDA released a public health notification (PHN) alerting the public about “rare” complications and problems related to transvaginal mesh products used for pelvic organ prolapse. In 2011, the FDA modified this alert by removing the term “rare” and stating that surgical mesh for pelvic organ prolapse repair does not conclusively improve outcomes over traditional nonmesh or native tissue repairs and is associated with unique potentially serious adverse outcomes
FDA advisory panel deemed existing MUS products “safe and effective”
Even though the FDA has determined that existing MUS products are safe and effective, this unfortunately does not prevent MUSs from being caught up in the fervor of litigation related to products used for pelvic organ prolapse repair.
Single-incision sling manufacturers are required to perform 522 postmarket surveillance studies

Questions

In the integral theory, what components support the proximal and midurethra
What UDS values are suggestive of intrinsic sphincter deficiency?
List 5 differences between MUS and PVS
What are the most commonly used autologous materials in PVS?
What are advantages vs. disadvantages of synthetic PVS?
What were the main findings of the SISTEr trial?
What are the typical presenting symptoms in a patient with obstruction following PVS?
What is the surgical management of voiding dysfunction after PVS?
What is the management of PVS perforation?
What is the closest vascular structure related to the retropubic MUS approach?
How do outcomes in the elderly differ from the young after MUS surgery?
List complications associated with MUS
What is the management of urinary retention after MUS?

Answers

In the integral theory, what components support the proximal and midurethra

Pubourethral ligaments
Suburethral vaginal hammock
Pubococcygeus muscle

What UDS values are suggestive of intrinsic sphincter deficiency?
List 5 differences between MUS and PVS
- PVS: positioned at bladder neck, predominantly uses autologous material, complicated by donor graft morbidity, corrects ISD and hypermobility, can be used to correct SUI concomitant with urethral diverticular repair, higher risk of post-operative voiding dysfunction
- MUS: positioned at midurethra, predominantly uses synthetic material, not complicated by donor morbidity, corrects hypermobility only, cannot be used to correct SUI concomitant with urethral diverticular repair, lower risk of post-operative voiding dysfunction
What are the most commonly used autologous materials in PVS?
What are advantages vs. disadvantages of synthetic PVS?
What were the main findings of the SISTEr trial?
What are the typical presenting symptoms in a patient with obstruction following PVS?
What is the surgical management of voiding dysfunction after PVS?
What is the management of PVS perforation?
What is the closest vascular structure related to the retropubic MUS approach?
How do outcomes in the elderly differ from the young after MUS surgery?
List complications associated with MUS
What is the management of urinary retention after MUS?

References

Wein AJ, Kavoussi LR, Partin AW, Peters CA (eds): CAMPBELL-WALSH UROLOGY, ed 11. Philadelphia, Elsevier, 2015, chap 84