Clinical and urodynamic outcomes of pubovaginal sling procedure with autologous rectus fascia for stress urinary incontinence

Authors


Takahiko Mitsui md phd, North-15, West-7, Kita-ku, Sapporo 060-8638, Japan. Email: mitsui68@med.hokudai.ac.jp

Abstract

Aim:  We report the clinical and urodynamic outcomes of the pubovaginal sling procedure with autologous rectus fascia for stress urinary incontinence (SUI) and determined the urodynamic parameters that could predict the occurrence of postoperative voiding difficulty.

Methods:  Between 1998 and 2005, a total of 29 consecutive women with SUI underwent pubovaginal sling surgery with autologous rectus fascia. Patients were preoperatively and postoperatively evaluated with regard to symptoms and urodynamic findings including uroflowmetry (UFM), postvoid residual urine volume (PVR), filling cystometry (CMG) and pressure flow study (PFS).

Results:  Overall SUI was cured in 23 patients (80%) and improved in 3 patients (10%). Three patients (10%) who developed persistent urinary retention or severe voiding difficulty after surgery underwent urethrolysis. Of 17 patients who had urgency before the pubovaginal sling, urgency was cured postoperatively in seven, while de novo urgency appeared in one patient. Maximum flow rate (Qmax) in UFM was significantly decreased (P < 0.05) and PVR was increased (P = 0.08) after surgery. PFS showed a significant increase in detrusor opening pressure and detrusor pressure at Qmax (P < 0.01) after surgery. Eight patients (28%) needed prolonged intermittent self-catheterization. Patients who had PVR >100 mL (P < 0.05) or Qmax ≤20 mL/s (P = 0.09) in preoperative UFM were more likely to require prolonged intermittent catheterization after surgery.

Conclusions:  The pubovaginal sling procedure with autologous rectus fascia is an effective treatment for SUI. A comparison of preoperative and postoperative urodynamic parameters indicates an increase in urethral resistance after pubovaginal sling surgery. PVR >100 mL and Qmax ≤20 mL/s before surgery are risk factors for postoperative voiding difficulty.

Introduction

Stress urinary incontinence (SUI) is a devastating condition and affects patients' quality of life. The reported incidence of SUI in women is between 5% to 52%.1,2 SUI has been classified into three types based on urethral hypermobility and intrinsic sphincter deficiency.3 Historically, pubovaginal fascial sling procedure has been performed only for patients with type 3 SUI or intrinsic sphincter deficiency.4,5 However the indication of the pubovaginal fascial sling procedure has been extended as an effective treatment for all types of SUI with acceptable long-term efficacy.6 Since 1998, the pubovaginal sling procedure using autologous rectus fascia has been performed for female patients with all types of SUI in our hospital.

Contrary to the high success rate in all types of SUI, the pubovaginal sling procedure has been reported to have a negative side that includes a relatively high incidence of urinary retention (5–20%), voiding difficulty (1.5–7.8%) and de novo urgency incontinence (3–19%) after surgery.6,7 These complications may be attributed to the increased urethral closure pressure by the pubovaginal sling. So far, only a few papers have addressed the role of preoperative urodynamic parameters as a predictor of voiding dysfunction after the surgery.8–10 It is important to identify preoperative risk factors and to counsel patients about the expected length of postoperative urinary drainage and the type of drainage to be used when obtaining the patient's consent.

In the present study, we report the clinical and urodynamic outcomes of the pubovaginal sling procedure with autologous rectus fascia for SUI in women and determined the urodynamic parameters that could predict the occurrence of postoperative voiding dysfunction.

Patients and methods

Between 1998 and 2005, a total of 29 consecutive women with SUI underwent pubovaginal sling surgery with autologous rectus fascia in our hospital. These patients were reviewed retrospectively. Preoperative assessment consisted of detailed urinary history, physical and neurological examinations, urinalysis and urodynamics including uroflowmetry (UFM) and postvoid residual urine volume (PVR), filling cystometry (CMG) and pressure flow study (PFS). The degree of cystocele, rectocele and vault prolapse was assessed and graded with the patients in the supine position and straining.11

Methods, definitions and units of urodynamics conform to the standards recommended by the International Continence Society except where specifically noted.12 Free UFM was performed before urethral instrumentation. Patients were then catheterized and CMG or PFS was performed with a filling of room temperature normal saline at 30–50 mL per minute through a 6 Fr double lumen catheter. The lowest intravesical pressure at 150 mL bladder capacity during cough and valsalva that produced urine leakage was defined as the abdominal leak point pressure (ALPP). The type of SUI in each patient was determined according to the value of ALPP; Intrinsic sphincter deficiency (ALPP ≤60 cmH2O); intermediate type (60 < ALPP ≤ 90 cmH2O); and hypermobility of the bladder neck (ALPP >90 cmH2O).

We modified the surgical technique that was reported by Cross et al.7 Briefly, the patients were placed in the dorsal lithotomy position allowing free access to the perineum and lower abdomen. If a hysterectomy was to be performed, it was done at first. A midline vaginal incision was made overlying the proximal urethra and then the vaginal epithelium was sharply dissected off the underlying periurethral fascia. After dissection of the proximal urethra laterally, superficial to the white periurethral fascia, entrance into the retropubic space was made at the lateral margin of the periurethral fascia using curved scissors, and created the retropubic space with blunt finger dissection. Then, a transverse suprapubic incision was made two fingers breadth above the symphysis. The fascial sling was harvested from the inferior leaf of the rectus fascia, measuring 5 cm in length and 1 cm in width, and then the sling was oversewn at both ends with heavy nonabsorbable suture with the stitches placed perpendicular to the sling. Following dissection of the retropubic space into the endopelvic fascia, an entrance was made in the endopelvic fascia and a long curved clamp was manually guided from the abdomen, through the retropubic space, under the pubis and into the vaginal incision. The sling sutures were grasped by the clamp and pulled up into the abdominal incision. At the level of the proximal urethra, the sling was sutured to the periurethral fascia with an absorbable suture. At this step, if a cystocele repair was to be performed, dissection continued to the base of the bladder and a standard anterior colporrhaphy was performed. After the sling was in position, the vaginal incision was closed with absorbable suture. The sling sutures were brought through the lower leaf of the rectus fascia and the rectus fascia was closed. Urethral mobility was tested by urethrocystoscopy and the sling sutures were tied over the closed rectus fascia without tension. A vaginal pack was placed and the abdominal incision was closed.

Surgical outcome in the continence status was defined at three or more months during follow-up after surgery using a questionnaire assessment reported by patients themselves or referring to medical charts when patients were interviewed. The patient was considered cured if she was not incontinent under any circumstances. The patient was considered improved or failed if she had a 50% or more reduction in incontinence or if she had less than a 50% reduction in incontinence, respectively. The patients were also asked about preoperative and postoperative urgency. Urodynamics including UFM, PVR, CMG and PFS were reexamined three months after surgery.

Statistical analysis was performed using Mann–Whitney's U-test and Fisher's exact test. P-value less than 0.05 was considered significant.

Results

Median patient age was 64 years (43–79 years) at the time of surgery. Thirteen of 29 (45%) patients had undergone prior pelvic surgery and two other patients (7%) had undergone prior anti-incontinence surgery. Concomitant surgery was anterior colporrhaphy in 10 (35%) and anterior colporrhaphy with hysterectomy in 6 (21%). The type of urinary incontinence was intrinsic sphincter deficiency in 7, intermediate type in 11 and hypermobility of the bladder neck in 11. Median follow-up period after surgery was 25 months (5–91 months)

Before surgery, all patients complained of SUI. Overall SUI was cured in 23 (80%) and improved in 3 (10%) with at least one year follow-up (Table 1). In the remaining three patients (10%), surgical outcome was defined as failed because they developed severe voiding difficulty or permanent urinary retention after surgery. For these three patients urethrolysis was performed 14 days, 1 month and 38 months after surgery (Table 1). After urethrolysis, voiding function successfully recovered without severe urinary incontinence in two patients, while voiding disturbance persisted and urinary incontinence recurred in the other patient. The success rate was not different among those with intrinsic sphincter deficiency, intermediate type and hypermobility of the bladder neck (Table 1).

Table 1.  Subjective outcome of stress urinary incontinence
  • Urethrolysis was performed. ALPP, abdominal leak point pressure.

Overall
 CuredImprovedFailed
23 (80%)3 (10%)3 (10%)
Type of urinary incontinence
 ALPP (cmH2O)CuredImprovedFailed
 ≤60 (n = 7)6 (86%)1 (14%)0 (0%)
 >60, ≤90 (n = 11)8 (73%)2 (18%)1 (9%)
 >90 (n = 11)9 (82%)0 (0%)2 (18%)

Before pubovaginal sling surgery, 17 patients (59%) had urgency, of whom urgency resolved in 7 and persisted in 10 after surgery. De novo urgency appeared in one patient. Thus preoperative and postoperative overall incidence of urgency was 59% and 38%, respectively (Table 2). Of 11 patients who had urgency postoperatively, six had urgency incontinence (Table 2). Urgency incontinence disappeared in four patients after taking medication such as anticholinergic agents and another two patients underwent urethrolysis. Bladder capacity and incidence of detrusor overactivity on CMG did not change significantly after pubovaginal sling surgery (Table 2).

Table 2.  Overactive bladder symptoms and filling cystometry (CMG) parameters
  1. CMG, filling cystometry.

Overactive bladder symptoms
 UrgencyUrgency incontinence
 Before surgery17 (59%)not assessed
 After surgery11 (38%)6 (21%)
CMG parameters
 (n = 22)Before surgeryAfter surgery
 Bladder capacity (mL)424 ± 24387 ± 21
 Detrusor overactivity2 (9%)2 (9%)

The results on voiding function are shown in Table 3. Except three patients (10%) who underwent urethrolysis, efficient voiding finally returned in 26 patients (90%). Eight patients (28%) needed prolonged (more than one month after surgery) intermittent self-catheterization and that period ranged from 4 to 40 months. The maximum flow rate (Qmax) in free UFM was significantly decreased from 27.8 ± 4.2 to 16.7 ± 2.5 mL/s (P < 0.05) and PVR was increased from 38 ± 14 to 91 ± 24 mL (P = 0.08) after pubovaginal sling surgery. PFS showed a decrease in Qmax (P = 0.06) and a significant increase in detrusor opening pressure (Pdet.open) from 13.7 ± 1.9 to 24.3 ± 2.8 cmH2O and detrusor pressure at Qmax (Pdet.Qmax) from 18.2 ± 1.9 to 29.7 ± 3.3 cmH2O (P < 0.01).

Table 3.  Voiding function
UFM/PVR
(n = 18)
Before surgeryAfter surgeryP-value
  1. Pdet.open, detrusor opening pressure; Pdet.Qmax, detrusor pressure at Maximum flow rate; PFS, pressure flow study; PVR, postvoid residual urine volume; UFM, uroflowmetry.

 Qmax (mL/s)27.8 ± 4.216.7 ± 2.5P < 0.05
 PVR (mL)38 ± 1491 ± 24P = 0.08
PFS
(n = 19)Before surgeryAfter surgeryP-value
 Qmax (mL/s)22.6 ± 3.314.9 ± 2.0P = 0.06
 Pdet.open (cmH2O)13.7 ± 1.924.3 ± 2.8P < 0.01
 Pdet.Qmax (cmH2O)18.2 ± 1.929.7 ± 3.3P < 0.01

Risk factors for the delayed return of efficient voiding were analyzed, because we observed 8 patients (28%) who needed prolonged intermittent self-catheterization after pubovaginal sling surgery. The patients who had PVR more than 100 mL (P < 0.05) or Qmax in free UFM 20 mL/s or less (P = 0.09) before surgery were more likely to require prolonged intermittent self-catheterization after surgery (Table 4).

Table 4.  Risk factors for delayed return of efficient voiding
 Prolonged self-catheterizationFisher's exact test
(–)(+)
  1. Pdet.Qmax, detrusor pressure at Maximum flow rate; Qmax, Maximum flow rate; PVR, postvoid residual urine volume.

Pdet.Qmax (cmH2O)
 ≤12 (n = 7)43n.s.
 >12 (n = 22)175 
Qmax (mL/s)
 ≤20 (n = 12)66P = 0.09
 >20 (n = 15)132 
PVR (mL)
 ≤100 (n = 22)184P < 0.05
 >100 (n = 5)14 

Discussion

We analyzed the clinical and urodynamic outcomes of the pubovaginal sling procedure with autologous rectus fascia for SUI and determined which urodynamic parameters could predict postoperative voiding difficulty. The pubovaginal sling procedure with autologous rectus fascia is an effective treatment for SUI with an 80% cure rate of SUI and an additional 10% improvement rate. A comparison of the preoperative and postoperative urodynamic parameters indicates an increase in urethral resistance after pubovaginal sling surgery. PVR more than 100 mL and Qmax less than 20 mL/s before surgery were risk factors for postoperative voiding difficulty.

Overactive bladder symptoms such as urgency and urgency incontinence can be associated with SUI. In the present study, 17 patients (59%) had urgency as an associated symptom. As possible causes of overactive bladder associated with SUI, several factors are implicated that include weakness of the support provided by the muscle and connective tissue in the bladder neck and urethra, changes of abdominal pressure transmission to the urethra and neuromuscular disorder in the urethra. There has been no convincing theory, however, that explains the difference between SUI with and without an overactive bladder. In the present study, urgency was cured in 7 of 17 patients (41%) after surgery. This finding indicates that the strengthened support of the bladder neck and urethra by fascial sling may contribute to the resolution of an overactive bladder in some patients. Meanwhile, de novo urgency is a perplexing condition that could hamper the therapeutic benefit of anti-incontinence surgery. Bladder outlet obstruction and damage to bladder autonomic innervation by the sling procedure are implicated as possible pathogenesis of de novo urgency. However, the precise mechanisms of de novo urgency are poorly understood. In the present study, de novo urgency and de novo detrusor overactivity appeared in only one patient each after surgery. The incidence of de novo urgency in the present study (8%) is similar to the previous data of pubovaginal sling surgery6,7 and are not worse compared to data of the tension-free vaginal tape procedure.13

A comparison of the preoperative and postoperative urodynamic findings revealed a significant decrease in Qmax and an increase in PVR on free UFM, and a significant increase in Pdet.open and Pdet. Qmax on PFS after surgery, while no significant difference was noted in bladder capacity or the incidence of detrusor overactivity. These results of urodynamics suggest that pubovaginal sling surgery increases urethral resistance. In fact, eight patients (28%) in the present study needed prolonged intermittent self-catheterization after surgery and urethrolysis was performed in three patients (10%). An increase of urethral resistance may be implicated in the blunt dissection of periurethral fascia and endopelvic fascia, which can easily make the urethra pull upward in the sling procedure, even if the sling procedure is performed tension free. Currently, when the sling sutures are tied over the closed rectus fascia, the urethra is pulled downward by urethrocystoscopy to avoid urethral obstruction with the sling.

Although pubovaginal sling surgery with autologous fascia is traditionally an excellent suburethral procedure for women with SUI, harvesting an autologous fascia graft increases operative time, causes postoperative pain, and lengthens recovery. Nowadays, a very popular procedure is sling surgery using a synthetic graft such as polypropylene tape, which can obviate the need for autologous tissue, decrease operative time, hasten postoperative recovery and represent a similar efficacy rate to the autologous fascial sling procedure.14,15 We hesitate to perform sling procedure using a synthetic graft of polypropylene tape for complicated cases such as those with previous pelvic surgery or prior anti-incontinence surgery, however, because of the possibility of some complications.16 These include major complications such as bladder or urethral perforation, bowel injury, major vascular injury, nerve injury, abscess requiring drainage, any transfusion, significant bleeding, or hematoma requiring surgical drainage, which are reported to be more common than what is indicated in the published reports.16,17 In the present study, 13 of 29 (45%) patients and 2 other patients (7%) had undergone prior pelvic surgery and anti-incontinence surgery, respectively. Thus we selected pubovaginal sling surgery with autologous fascia for these patients who were referred to our hospital. Even for these relatively complicated cases, we could perform autologous fascial sling surgery without any complications and clinical outcome because SUI was the same as those without a history of previous surgery. Although tension-free vaginal tape (TVT) seems to be a very effective and the most popular procedure for uncomplicated cases with SUI, we believe that the pubovaginal sling procedure with autologous fascia still has an important role in surgical armamentarium for complicated cases with SUI and for those with recurrent SUI due to failed TVT.

We also analyzed the risk factors for postoperative voiding difficulty, because postoperative voiding difficulty has been a great concern about the use of pubovaginal sling. Patients who had PVR more than 100 mL (P < 0.05) or Qmax in free UFM 20 mL/s or less (P = 0.09) in preoperative urodynamics were more likely to require prolonged intermittent self-catheterization after pubovaginal sling surgery. Previous papers reported several risk factors for postoperative urinary retention and the delayed return of efficient voiding that included weak detrusor9 or preoperative Valsalva maneuver during voiding.10 Other factors, such as age over 65 years, additional surgical procedures and low Qmax in UFM are also risk factors for delayed voiding.8 Low Qmax in UFM is also a predictor for postoperative long-term voiding difficulty after surgery using a synthetic graft of polypropylene tape.18,19 Unfortunately, there have been heterogeneous outcomes with regard to risk factors for postoperative voiding difficulty. These variable results might be attributed to different surgical techniques and different criteria on normal voiding between studies. The difference in surgical volume between surgeons might also cause variable results. More studies are necessary to elucidate the role of preoperative voiding parameters as a predictor of postoperative voiding difficulty.

In conclusion, the pubovaginal sling procedure with autologous rectus fascia is an effective treatment for SUI. A comparison of the preoperative and postoperative urodynamic parameters indicates an increase in urethral resistance after pubovaginal sling surgery. PVR more than 100 mL and Qmax less than 20 mL/s before surgery are risk factors for postoperative voiding difficulty.

Ancillary