Intrinsic urethral sphincteric deficiency: critical analysis of various diagnostic modalities

Regenerative medicine and injection therapies in stress urinary incontinence

Stress urinary incontinence (SUI) is a common and bothersome condition. Anti-incontinence surgery has high cure rates, but concerns about mesh tapes have resulted in the resurgence of surgical procedures that involve increased abdominopelvic dissection and morbidity. Injection therapy with urethral bulking agents or stem cell formulations have been developed as minimally invasive alternatives. Many synthetic and biological bulking agents have been trialled, but several have been discontinued owing to safety concerns. The use of Macroplastique and Contigen has the largest evidence base, but, overall, success rates seem to be similar between the various agents and positive outcomes are poorly sustained for more than 6 months. Furthermore, subjective cure rates, although initially high, also deteriorate over time. The available data consistently demonstrate manifestly poorer outcomes for injection therapies than for surgery. Stem cell treatments are thought to functionally regenerate the urethral sphincter in patients with suspected intrinsic sphincter deficiency. Autologous adipose and muscle-derived stem cells seem to be the intuitive cell source, as they are comparatively abundant, can be harvested and cause minimal donor site morbidity. To date, only a few small clinical studies have been reported and most data are derived from animal models. The success rates of stem cell injection therapies seem to be comparable with those of bulking agents.

Considerations in the modern management of stress urinary incontinence resulting from intrinsic sphincter deficiency

PURPOSE

Intrinsic sphincter deficiency (ISD) is a common cause of stress urinary incontinence and is associated with more severe symptoms, often being associated with failed previous surgery. Due to the impaired sphincteric function, alternative surgical approaches are often required. The purpose of this review is to appraise the contemporary literature on the diagnosis and management of ISD.

METHODS

A PubMed search was performed to identify articles published between 1990 and 2014 using the following terms: ISD, stress urinary incontinence and type III stress urinary incontinence. Publications were screened for relevance, and full manuscripts were retrieved.

RESULTS

Most studies base the diagnosis of ISD upon urodynamic appearances using recognized criteria (Valsalva leak point pressure <60 cm H2O or a maximum urethral closure pressure <20 cm H2O) in addition to clinical features. A range of non-surgical and surgical treatment options are available for the patient. Pubovaginal slings are more effective than retropubic colposuspensions with outcomes comparable to those reported with midurethral slings. The artificial urinary sphincter provides long-term cure rates; however, it is associated with specific morbidity including device erosion, mechanical failure and revision. The benefits of bulking agents, however, are not sustained beyond 1 year.

CONCLUSIONS

There are few randomized controlled trials that compare accepted treatments specifically for patients with ISD. The lack of standardization in the definition and diagnostic criteria used limits inter-study comparisons. An assessment of urethral pressure profile when combined with the clinical features may help predict outcomes of surgical intervention.

Clinical factors associated with low valsalva leak point pressure among women with stress urinary incontinence

Purpose

The purpose of this study is to determine the predictive factors that are associated with stress urinary incontinence (SUI) due to intrinsic sphincter deficiency (ISD) in women.

Methods

Between January 2008 and December 2009, 185 women with urodynamically proven SUI were included in this study and retrospectively reviewed the medical record. Preoperative SUI symptoms were classified by Stamey grade. Valsalva leak point pressure (VLPP) determination series was repeated two times in each subject after finishing one series of VLPP measurement. The patients were classified into three groups according to VLPP; 1) ISD: VLPP≤60 cm H₂O, 2) equivocal: 60<VLPP≤90 cm H₂O, 3) anatomical incontinence (AI): VLPP>90 cm H₂O. Chi-square test and multivariate (logistic regression test) analyses were performed to determine the factors associated with ISD.

Results

The mean patient age was 54.2 years (range, 44.5 to 68.4 years). Seventy-one women (38.3%) were in the ISD group and 70 (37.8%) in the AI group. The results of univariate and multivariate analyses found that women with ISD had a higher symptom grade than women with AI (P=0.001 and 0.0001, respectively). The number of patients in the ISD and AI group in accordance with the symptom grade were 7 (10%) and 44 (62%) in grade I, 50 (54%) and 23 (25%) in grade II, and 14 (63%) and 3 (14%) in grade III respectively. There was no correlation between VLPP and other clinical factors.

Conclusions

High symptom grade was the only independent clinical factor that predicted the presence of ISD. This should be considered when counseling the patients with SUI.

Urinary retention after orthotopic neobladder substitution in females

PURPOSE

Urinary retention is a common complication after orthotopic neobladder urinary diversion. We reviewed a case series of women who underwent neobladder creation and discuss anatomical findings, and urinary retention etiology and prevention.

MATERIALS AND METHODS

We retrospectively reviewed the records of all orthotopic neobladder urinary diversions in female patients performed at our institution from 1999 through 2010. We abstracted baseline clinical and demographic characteristics, operative information, and postoperative clinical, urodynamic, imaging and secondary procedure followup. We defined urinary retention as the need for intermittent catheterization.

RESULTS

We identified 21 female patients who underwent neobladder diversion. Median age at cystectomy was 62 years (range 43 to 77). Median followup was 3 years (range 3 to 138 months). Of the patients 14 underwent ileocolic diversion, 6 underwent Studer ileal diversion and 1 underwent preservation of a right colon augmentation. All patients underwent prior or concurrent hysterectomy. In 2 patients with a history of genitourinary tuberculosis neobladder-vaginal fistulas developed postoperatively and they were excluded from analysis. Of the 19 female patients with a neobladder included in analysis 7 (36.8%) experienced urinary retention requiring clean intermittent catheterization. Associated abnormalities included neocystocele formation in 6 cases, anastomotic stricture in 1 and progressive neurological disease in 1. Upon straining the average neobladder descent was approximately 2 cm and the average change in the neocystourethral angle in patients with neocystoceles was 18 degrees. Of the patients 11 (57.9%) had a nonobstructive voiding pattern.

CONCLUSIONS

Urinary retention in female patients with a neobladder can be functional, anatomical or multifactorial. In our series common anatomical findings associated with urinary retention were neocystocele formation and urethral kinking.

Implantation of autologous bone-marrow-derived cells reconstructs functional urethral sphincters in rabbits

The purpose of this study was to determine if implantation of autologous bone-marrow-derived cells has the potential to treat stress urinary incontinence caused by intrinsic sphincter deficiency. Bone marrow cells harvested from femurs of New Zealand White rabbits were cultured for 10 days. Seven days before implantation, the urethral sphincters located at the internal urethral orifice were cryo-injured by spraying liquid nitrogen for 15 s. The cultured autologous bone-marrow-derived cells were implanted 7 days after cryo-injury. For controls, cell-free solutions were injected. At 7 and 14 days after implantation, leak point pressures were determined and the urethral sphincters were examined by immunohistochemistry. At 7 and 14 days, the cell-implanted regions contained numerous striated and smooth muscle-like cells expressing myoglobin and smooth muscle actin, respectively. The proportions of myoglobin- and smooth muscle actin-expressing areas in both the 7- and 14-day cell-implanted regions were significantly higher than in controls. By 14 days, these differentiated cells formed contacts with similar cells, creating layered muscle structures. At that time, the leak point pressure of the cell-implanted rabbits was significantly higher than that of the controls. In conclusion, autologous bone-marrow-derived cells can reconstruct functional urethral sphincters.

Accuracy of methods for urinary detection in women with stress urinary incontinence

Purpose

We assessed the accuracy of urinary detection by visualization compared with a method using the urethral channel of a transurethral, three-channel urodynamic catheter.

Materials and Methods

This was a case series of 52 patients presenting with stress urinary incontinence over 2 years. Patients underwent video-urodynamic studies in both the supine and the erect positions by use of two techniques for measuring leak point pressure (LPP) by one examiner. LPP was determined as the intravesical pressure simultaneous to the starting point of urethral pressure changes through the urethral channel of a urodynamic catheter (LPP-ure) and then by visualization (LPP-vis) during different events. We also measured the time related to the provocations and the time to mark the leakage on the urodynamic machine by the examiner.

Results

The LPP-ure values (cough supine: 42.1±18.7, cough erect: 42.1±21.8, Valsalva supine: 42.2±23.3, Valsalva erect: 41.0±22.6 cmH₂O) were significantly lower than the LPP-vis values (89.9±29.4, 97.4±30.4, 70.6±25.2, and 74.4±32.6 cmH₂O, respectively, all p<0.001). Whereas the actual leakages happened during the pressure increases, urodynamic recording by visualization was done after those increases had finished.

Conclusions

The use of visualization as a urinary detection method entails potential errors that cannot be adjusted for on that time scale. Our results emphasize the need to standardize the methodologies used for urinary leakage detection, because this measurement is closely related to the accuracy of measurement of leak point pressure.

The Fate of Implanted Syngenic Muscle Precursor Cells in Injured Striated Urethral Sphincter of Female Rats

We studied the outcome of syngenic skeletal muscle precursor cells (MPCs) implanted in the striated urethral sphincter of the female rat. These cells were injected at the site of a longitudinal sphincterotomy performed 21 days before implantation. MPCs were isolated from the striated hindlimb muscles of syngenic adult rats and were infected with a retrovirus carrying the gene for either the green fluorescent protein (GFP) or the β-galactosidase enzyme (β-gal). MPCs (2 × 105) were injected longitudinally at the site of the lesion in 48 animals using a 10-μl Hamilton syringe. Then the whole urethras were excised from 2 h up to 90 days for cross section immunocytochemistry analysis. All the urethras exhibited connective tissue in place of the injury of the striated fibers. Two hours after injection a cluster of small round basophilic cells was observable at the site of injection and some of them expressed GFP or β-gal. A few GFP- and β-gal-positive cells were already detectable 7 days after injection. A large amount of injected cells probably died after injection. Many striated fibers of the urethra became GFP positive from day 7 until day 21, suggesting that few MPCs were allowed to incorporate the divided extremities of the striated fibers from day 7. Unfortunately, we did not observe centronucleated regenerated fibers in this experiment.

A comparison of periurethral blood flow resistive indices and urethral closure pressure of incontinent women

This study correlated Doppler resistive indices (RIs) with maximum urethral closure pressures (MUCPs) in women with stress urinary incontinence. We hypothesized that urethral blood flow would be inversely correlated to urethral closure pressures. Fifty-three women underwent spectral Doppler waveform analyses of periurethral vasculature to calculate RI. Urethral morphology including pubovesicular length (PVL) with and without cough was measured. MUCPs were obtained according to International Continence Society guidelines. Physical exam and history were also obtained. Correlation coefficients were calculated for comparisons of Doppler measurements and closure pressures. Fifty patients were required to detect a difference between no correlation and a modest correlation of 0.38 with 80% power and alpha of 0.05. Significance is set at p<0.05. Measurements were reproducible between Doppler waveforms and MUCP measurements (all p=NS). RI was not correlated with age, parity, MUCP, Incontinence Impact Questionnaire-7 scores, urethral length, or urethral width (all p=NS). RI and MUCP were likewise not associated with history of diabetes, hypertension, or anterior vaginal prolapse to or beyond the hymen (all p=NS). MUCP was negatively correlated with age (r=-0.33, p=0.01) even when controlled for hormonal status (ANCOVA, p=0.003) and positively correlated with urethral/bladder neck diameter (r=27, p=0.05), PVL (r=0.30, p=0.03), and PVL with cough (r=0.36, p=0.009).

Significance of pad test loss for the evaluation of women with urinary incontinence

AIMS

The aim of this study was to determine whether the objective incontinence severity, as measured by the pad test, correlated with urethral parameters, and if the objective incontinence severity was differentiated by the incontinence types and also, if it influenced the patient's clinical outcome.

METHODS

Two hundred seventy-four female patients who had undergone a tension-free vaginal tape procedure between March 1999 and May 2003 were retrospectively reviewed. The 1 hr pad test was carried out as recommended by the International Continence Society, with some modification. The mean patient age was 55.1 years (range: 28-80). Two hundred-one women (73.3%) that complained of stress urinary incontinence and another 73 women (26.7%) that had additional symptoms of urge incontinence were enrolled as study subjects. A cure for incontinence, after the tension-free vaginal tape procedure, was defined as the absence of a subjective complaint of leakage and the absence of objective leakage on stress testing, and all other cases were considered failures.

RESULTS

In linear regression analysis, the Valsalva leak point pressure (VLPP) was the only explanatory variable influencing the objective incontinence severity. The urine leakage was significant higher in the mixed urinary incontinence group than in the stress urinary incontinence group (39.7 +/- 7.5 g vs. 30.3 +/- 2.8 g, P < 0.05). For the total patients, the failure group had a more severe preoperative objective severity than the cure group (53.2 +/- 16.6 vs. 32.0 +/- 3.0, P < 0.05). Upon a subgroup analysis, a similar result was found in the stress urinary incontinence group (87.1 +/- 8.2 vs. 29.8 +/- 2.8, P < 0.05) but not in the mixed urinary incontinence group.

CONCLUSIONS

Our findings suggest that the amount of urine leakage as measured during the pad test may be associated with the clinical outcome, after the anti-incontinence surgery.