Observations on the function of the female urethra: II: Relation between maximum urethral closure pressure at rest and the degree of urethral incompetence

AIMS: To study the relation between maximum urethral closure pressure (MUCP) at rest and the degree of urethral incompetence in the female. PATIENTS AND METHODS: Two hundred fifty five patients aged 20 years or older, with stable bladders on multichannel urodynamics, without known neurological pathology, and with no previous history of pelvic or anti-incontinence surgery were included in the study. Resting urethral pressure profile (UPP) and the grade of urethral incompetence was registered. RESULTS: Mean age of the group was 45.6+/-12.7 years; mean MUCP was 62.7+/-28.5 cm of water. There was a statistically significant difference in the MUCP when the different grades of urethral incompetence were compared to each other, the higher grades being associated with a lower maximal closure pressure. CONCLUSIONS: This study demonstrates that there is a highly significant relationship between MUCP and between all grades of urethral incompetence. This supports previous observations that MUCP decreases when abdominal leak point pressure (ALPP) is low and that this might be secondary to some mechanical failure in the pressure transmission from the abdominal cavity to the urethra. Studies should never compare continent to incontinent cohorts without considering their ALPP because in doing so they are comparing groups that are functionally heterogeneous.     

Observations on the function of the female urethra: III: An overview with special reference to the relation between urethral hypermobility and urethral incompetence

AIMS: To analyze the relation between urethral hypermobility and urethral incompetence, and to summarize the interdependence between maximum urethral closure pressure (MUCP), urethral hypermobility, and urethral incompetence. PATIENTS AND METHODS: A group of 255 patients was selected from a large bank of cases. Inclusion criteria were age 20 years or above, no neurological disease, stable bladder, and no previous incontinence surgery or hysterectomy. The degree of hypermobility (cysto-urethrocele) and the degree of urethral incompetence (abdominal leak point pressure (ALPP)) were determined. Statistical analyses between urethral hypermobility and incompetence were performed with Spearman's correlation and the Jonckherre-Terpstra test. RESULTS: The Spearman's rank correlation test showed a statistically significant relation between urethral hypermobility and the degree of urethral incompetence (P = 0.0049). CONCLUSIONS: The statistically significant relation between urethral incompetence and hypermobility suggests that urethral incompetence will increase as the degree of urethral hypermobility does. Optimal conditions for urinary continence include a high maximum urethral closure pressure, absence of hypermobility, and a low degree of urethral incompetence. This last factor is assured by a strong support underneath the urethra permitting compression of the latter during straining. Failure of the urethral closure mechanism is highly probable with a diminished maximum closure pressure accompanied by urethral hypermobility often associated with a high degree of urethral incompetence. Clinically significant urinary incontinence may appear in many intermediate circumstances between these two extreme states, but stress urinary incontinence is essentially an activity-related phenomenon.     

女性尿道中静态尿道压力分布特点的研究

目的：探讨在女性尿道不同部位和不同方向上静态尿道压力图（RUPP）压力的分布特点。方法：本研究共包括因各种原因需做尿动力学检查的成年女性患者55例,年龄（41±11）岁,其中尿流动力学检查无异常者8例,压力性尿失禁19例,其他诊断（包括OAB、膀胱收缩无力等）28例。采用恒压恒速灌注法测压,将测压孔分别朝向尿道前壁（12点）、后壁（6点）、左侧壁（3点）及右侧壁（9点）四个方向描记RUPP,采用配伍区组方差分析进行统计学分析。结果：前壁的最大尿道闭合压（MUCP）最高（P％0．01）,后壁的MUCP最低（P〈0．001）,左右两侧MUCP无明显差异（P=0．571）;前壁的功能尿道长度（FUL）最短（P〈0．01）,后壁的FUL最长（P〈0．001）,左右两侧FUL无统计学差异（P=0．717）;RuPP曲线均呈抛物线形,高压区和MUCP的最大值位于尿道中段或中远段交界处。结论：本研究结果显示,静态尿道压力图在女性尿道压力分布上,前后壁方向上具有显著的方向性变异,而左右两侧具有对称性和一致性。尿道压力图的压力分布特点与女性尿道壁的组织结构和尿道腔的形态密切相关。     

The tension-free vaginal tape in women with a non-hypermobile urethra and low maximum urethral closure pressure

The objective of this study was to estimate the cure rate and to identify risk factors that predict failure of the tension-free vaginal tape (TVT) in women with stress urinary incontinence (SUI), a non-hypermobile urethra, and low maximum urethral closure pressure. Thirty-six women with SUI, a non-hypermobile urethra (straining urethral angle ≤35°), and low maximum urethral closure pressure (MUCP ≤25 cm H₂O) underwent a TVT. Cure was defined as resolution of subjective SUI symptoms and a negative cough stress test, which were measured after 4, 12, 18, and 24 months. Patient characteristics were compared and receiver–operator curves were used to identify risk factors for failure. The mean age was 71 years, and mean follow-up was 20.9 months. The overall cure rate was 78%. Risk factors for failure of the TVT were a straining urethral angle ≤20° (cure rate 50%, odds ratio 7.7, p = 0.02) and a MUCP ≤15 cm H₂O (cure rate 60%, odds ratio 6.3, p = 0.03). For women with both risk factors, the cure rate was only 17% (p < 0.001). No other risk factors were identified. The TVT has moderate success (50-60%) for women with SUI and one risk factor (a straining urethral angle </=20 degrees or a MVCP </=15 cm H₂O), but has poor success (17%) when both risk factors are present. Presented at the annual meeting of the Society for Gynecologic Surgeons, Dallas, TX, March 5–7, 2002. The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the Department of the Army or the Department of Defense.     

Fluid perfused urethral pressure profilometry and Valsalva leak point pressure: a comparative study in a biophysical model of the urethra

In patient studies the correlation between maximum urethral closure pressure (MUCP) and Valsalva leak point pressure (LPP) is meagre at best (r = 0.22–0.50). We therefore studied the relation between MUCP and LPP in a flexible and extensible model urethra. We applied differently sized pressure zones and different degrees of resistance to a biophysical model urethra by stepwise inflating three types of blood pressure cuff placed around the model. At each degree of resistance we measured detrusor LPP, an in vitro equivalent of Valsalva LPP. Subsequently, we recorded the Urethral Pressure Profile using a water-perfused 5F end-hole catheter at four withdrawal rates and five perfusion rates and calculated MUCP. We tested the dependence of LPP on pressure zone length and MUCP on perfusion rate, withdrawal rate and pressure zone length using analysis of variance. We tested the correlation between LPP and MUCP using Pearson’s correlation coefficient and Linear Regression. LPP did not significantly depend on the pressure zone length (P = 0.80) and increased linearly with increasing cuff pressure. MUCP also increased with increasing cuff pressure, however, MUCP significantly depended (P < 0.01) on perfusion rate, withdrawal rate and pressure zone length. MUCP increased with increasing perfusion rate, and decreased with increasing withdrawal rate. In our model urethra MUCP only accurately reflected urethral resistance for a very limited number of combinations of perfusion rate and withdrawal rate. LPP reflected urethral resistance independent of the type of pressure zone.     

Predictive value of maximum urethral closure pressure, urethral hypermobility and urethral incompetence in the diagnosis of clinically significant female genuine stress incontinence

PURPOSE: We determined the value of urethral hypermobility, maximum urethral closure pressure (MUCP) and urethral incompetence in the diagnosis of stress urinary incontinence (SUI). MATERIALS AND METHODS: In this study 369 women with clinical symptoms suggestive of SUI without symptoms of bladder overactivity were evaluated in regard to urethral incompetence, urethral hypermobility and mean MUCP. The cohort was divided into 2 groups according to continence/incontinence status. ROC curves were used to test the performance of the various predicting factors. These factors were combined in forward stepwise logistic regression to find the cutoff point that simultaneously optimized sensitivity and specificity. RESULTS: Continent and incontinent patients differed with regards to urethral incompetence and hypermobility (each p <0.0001). Incontinent patients had a greater probability of a higher grade of each factor. Even after adjusting for the older age of incontinent patients by ANCOVA. MUCP was significantly lower in the incontinent group (p <0.001). The best univariate optimized cutoff point for discriminating continence from incontinence was obtained with urethral incompetence greater than grade I. CONCLUSIONS: The best single predictor of clinically significant SUI is urethral incompetence, followed by urethral hypermobility and MUCP. When combining several factors, namely grade II urethral incompetence with grade III hypermobility, grade III urethral incompetence with grades I to III hypermobility and grade IV urethral incompetence with or without urethral hypermobility, all indicated more than a 90% probability of clinically significant SUI.     

Mechanical properties of the urethra in healthy female volunteers: Static measurements in the resting urethra

A pressure/cross-sectional area probe was used for measurement of related values of pressure (P_ura) and cross-sectional area (CA) at static circumstances in the resting urethra in 30 healthy females. Measurements were performed at the bladder neck in the high-pressure zone and distally in the urethra. From the two variables urethral elastance and hysteresis were calculated. The mean urethral elastance (i.e., dP_ura/dCA) was found to be of the order of 1 cm H₂O/mm² all along the urethra. No correlation could be established between the elastance and age or parity. The mean hysteresis was of the order of 20–25 cm H₂O along the urethra. Urethral hysteresis appeared to be a time-dependent phenomenon.     

Urethral pressure increase on effort originates from within the urethra,and continence from musculovaginal closure

The aim of the study was to determine the contribution of intra-abdominal pressure transmission to urinary continence in the female. Five patients with genuine stress incontinence (GSI) were studied. Pressure transmission was measured in equivalent positions inside and outside the urethra and bladder during the Intravaginal Slingplasty procedure, a surgical operation used for treatment of urinary incontinence, and performed under local anaesthesia. A 6 mm diameter channel was created alongside the urethra. Two separate microtransducer catheters appropriately marked for length were inserted, one inside the urethra, and the other inside the described channel. With the vaginal hammock intact, an average of 10 simultaneous pressure measurements were made intraoperatively in response to coughing and straining in equivalent positions inside the urethra, and directly outside. Significantly higher pressure readings were found inside the urethra (P = 0.0025), indicating that an active component within the urethra may have created this pressure rise. After opening out two suburethral vaginal flaps, large quantities of urine were lost on coughing in all patients Continence was achieved on tightening the suburethral vagina, indicating that an adequately tight vaginal hammock is a critical element in the continence process. The findings of this study question intraabdominal pressure as a mechanism contributing to continence, but support an alternative mechanism, musculovaginal closure of the urethra. © 1995 Wiley-Liss, Inc.     

Correlation between valsalva leak point pressure and maximal urethral closure pressure in women with stress urinary incontinence

This study analyzed the relationship between valsalva leak point pressure (VLPP) and maximal urethral closure pressure (MUCP) in women with stress urinary incontinence. One hundred sixty-one patients were selected with diagnosis of mixed or stress urinary incontinence. During urodynamics we measured VLPP and MUCP. Patients were gathered according to VLPP and analysis of variance (ANOVA) was performed. Pearsons correlation coefficient and linear regression were also utilized. The group with VLPP under 60 cm H₂O had mean MUCP of 44.5 cm H₂0; the group with VLPP between 60 and 90 cm H₂O had mean MUCP of 54.3 cm H₂O; and the group with VLPP over 90 cm H₂O had mean MUCP of 60.1 cm H₂O. We observed correlation between MUCP and VLPP when we used Pearsons correlation coefficient (r=0.22) and linear regression (p<0.05). There was weak correlation between MUCP and VLPP, and MUCP was significantly lower in patients with leak point pressure inferior to 60 cm H₂O. Editorial Comment: This is a retrospective study of 161 female patients with stress urinary incontinence in which the authors analyze the relationship between urodynamic valsalva leak point pressure (VLPP) and maximal urethral closure pressure (MUCP). In analyzing their data with Pearsons correlation coefficient and linear regression, the authors found a weak correlation between VLPP and MUCP. In addition, they found a significantly lower MUCP in patients with VLPP less than 60. The authors conclude that MUCP values less than 45 cm H₂O are not sensitive in diagnosing intrinsic sphincter deficiency. Although this study supports the known correlation between VLPP and MUCP, it adds little new information to the literature. This subject has previously been studied and evaluated and numerous published articles have already confirmed this correlation. It is already generally accepted that the diagnosis of intrinsic sphincter deficiency should be based on a compilation of factors including patient history, urodynamic, anatomic, and clinical severity criteria     

Abnormal urethral motor function is common in female stress, mixed, and urge incontinence

AIM: To investigate the urethral motor function in incontinent women. MATERIALS AND METHODS: The intraurethral pressure was measured continuously in the high-pressure zone of the urethra at rest and during repeated short squeezes around the microtip transducer catheter in a group of 205 women with clinically manifest urinary incontinence (severe), and compared with the findings of investigations in 87 middle-aged women (53-63 years) with treatment na?ve incontinence (mild-to-moderate) and healthy controls. RESULTS: Women with established incontinence significantly (P < 0.001) more often (66%) had a pressure fall during or immediately following squeeze than women with treatment na?ve incontinence (35%) or asymptomatic women (25%). The acceleration of urinary flow and the maximal flow rate were significantly (P < 0.01) increased in patients with incontinence: acceleration was 13 +/- 2.2 (17.8), 20 +/- 2.8 (18.9), and 32 +/- 4.9 (24.9) degrees (mean +/- SEM; SD) for incontinence, na?ve incontinence and no incontinence, respectively; maximum urinary flow rate was 23, 22, and 16 ml/sec. No statistical differences in any of these measures were seen when stress and urge incontinence were compared. CONCLUSION: Women with stress, urge, and mixed urinary incontinence seem to have a primary neuromuscular disorder in the urethra, which presents itself as an overactive opening mechanism with a urethral pressure fall instead of a pressure increase on provocation during the filling phase of the bladder, and during bladder emptying a more efficient opening of the bladder outlet than in normal women. We suggest that one and the same pathophysiological mechanism participates in female stress, urge, and mixed incontinence.     

Correlation of maximum urethral closure pressure with Valsalva leak point pressure using air-charged urodynamic catheters

Introduction and hypothesis  The objective of this study was to measure the correlation of maximum urethral closure pressure (MUCP) with Valsalva leak point pressure (VLPP) in women with urodynamic stress incontinence using air-charged urodynamic catheters. Methods  Records of all women who underwent urodynamic testing for urinary incontinence using air-charged catheters over a 3-year period were reviewed. Data included scores on the Urogenital Distress Inventory (UDI-6) and Incontinence Impact Questionnaire (IIQ-7). Results  One hundred ninety-three women met the criteria for urodynamic stress incontinence. There was a modest correlation of MUCP with VLPP at 200 mL (r = 0.46, p < 0.001) and a low correlation of MUCP with VLPP at maximum capacity (r = 0.35, p < 0.001). There was no correlation of UDI-6 or IIQ-7 scores with MUCP or VLPP. Conclusions  The low to modest correlation of VLPP with MUCP with air-charged catheters is similar to what has been reported with water-filled and microtransducer catheters.     

Continuous recording of urethral activity in healthy female volunteers

The pressure variations at the maximal urethral closure pressure (MUCP) were continuously recorded in healthy female volunteers by means of a two-point microtip transducer catheter for one hour. Before the investigation a normal voiding was assured objectively and bladder instability was excluded. All women showed pressure variations both at the MUCP and more distally. The pressure variations, from 3 to 66 cm H₂O, showed rhythmicity and three frequency ranges could be identified. Slow pressure waves with a frequency of one in eight to 19 minutes were observed. Relatively fast-pressure waves were observed (one every one to four minutes) and relatively fast-frequency pressure waves were observed (rate: one to eight per minute). The pressure variations of the urethra seem to be an aspect of normal urethral physiology possibly contributing to continence and urinary tract infection prevention.     

自制可调TVT吊带术后腹压漏尿点压和最大尿道闭合压变化分析

目的观察自制可调TVT吊带术后腹压漏尿点压(VLPP)和最大尿道闭合压(MCP)变化,探讨自制TVT吊带临床效果。方法女性压力性尿失禁患者134例,术前行尿流动力学检查测定VLPP、MCP,行自制TVT吊带手术治疗后随访患者再次检测VLPP和MCP,分析检查结果。结果按照世界尿控协会(ICS)标准有39例患者未检出VLPP,剩余95例患者VLPP手术前为(77.2±21.6)cm H2O(1cm H2O=0.098 k Pa),手术后为(99.7±26.3)cm H2O,二者比较差异具有统计学意义(P<0.05)。MCP手术前(32.5±14.3)cm H2O,手术后(57.2±13.3)cm H2O,二者差异具有统计学意义(P<0.05)。结论自制TVT吊带术后可以取得较满意的手术效果,并具有灵活的术后调整性,较传统手术具有自身优势。     

The urethral pressure profile at rest: An analysis of variance

Resting urethral pressure protile measurements were carried out by a microtransducer method on 100 women with a variety of urinary symptoms in an attempt to analyse the repeatability and reproducibility of the various protile parameters. The findings were as follows: The repeatability of parameters was shown to have some dependence on the rate of catheter withdrawal. being optiinal at 15 cm per minute. Profiles recorded by microtransducer showed greater consistency than those recorded by a fluid perfusion method. in terms of the parameters of urethral length. Whilst the fluid perfusion method has previously been shown to have a significant component of variance duc to time. no such time-dependent component was found with the microtransducer method. Urethral pressures measured by microtransducer do appear to have a significant time-dependence when recorded during the menstrual cycle in women of reproductive age. These findings suggest that the microtransducer method of urethral pressure measurement has a greater diagnostic reliability than the tluid perfusion method. It also has a greater capacity to assess the effects of drugs. hormones. and surgery on the urethral pressure profile. Care must be takcn. however. in the interpretation of pressure variations noted In women in reproductive age groups.     

Role of adrenoceptors in the proximal urethral function of female and male rabbits using an in vivo model of isovolumetric pressure generation

The role of alpha-1 and alpha-2 adrenoceptors in the contractile response of the proximal urethra to agonists and antagonists was studies in female and male New Zealand White rabbits. The response pattern for alpha-1 agonists showed a sharp rise, while that for alpha-2 agonists showed a gradual increase to a maximum pressure. The duration of the response of alpha-2 agonists was significantly longer than that of alpha-1 agonists. A difference in the response between alpha-1 and alpha-2 would be produced mainly through different receptor functions. The magnitude of the response of alpha-1 adrenoceptors in the male rabbits was almost twice that of the female rabbits. In contrast, the response of alpha-2 in the male rabbits was less than that of the female rabbits. Our experimental findings indicate that alpha-2 stimulation mediates a slow and prolonged response that is essential for urinary continence in female rabbits. © 1993 Wiley-Liss, Inc.     

Urethral pressure reflectometry; a novel technique for simultaneous recording of pressure and cross-sectional area in the female urethra

AIMS: Urethral pressure reflectometry (UPR) is a new and easily applicable technique for simultaneous measurements of cross-sectional area (CA) and pressure in the urethra. CAs of 1-16 mm(2) and pressures of 0-200 cm H(2)O can be measured along the entire urethra in the same setting. The method is reliable in vitro. The aim was to present the method and some clinical results from the female urethra. METHODS: A very thin polyurethane-bag was placed in the urethra. A pump applied preselected pressures stepwise to the bag. For every step the CA was measured by acoustic reflectometry. Measurements were made both during inflation and deflation. The women were examined in different positions and with different provocations. RESULTS: UPR was easy to perform. The obtained parameters were opening pressure, closing pressure, elastance of the opening curve and closing curve, and hysteresis. CONCLUSIONS: UPR is feasible for measuring urethral pressure and corresponding CA. The technique is minimally invasive and with minimal impact on the urethra per se. The technique provides physiological sound parameters which add potentially important physiological/pathophysiological information about the urethra to what can be obtained on the basis of conventional urodynamic work-up. Further studies are needed to prove if this new method is useful for clinical and research purposes.     

Mechanical properties of the urethra in females with genuine stress incontinence: Static measurements in the resting urethra

The pressure (P_ura)-cross-sectional area (CA) relationship in the resting urethra was examined in 30 females with genuine stress incontinence (GSI). Measurements were performed at the bladder neck, in the high-pressure zone, and in the distal part of the urethra. From the two variables urethral elastance (dP_ura/dCA) and hysteresis were calculated. The results were compared with those obtained in normal females. Urethral elastance, hysteresis, and urethral pressure showed significant differences at the three sites of measurement. Urethral elastance was significantly decreased at the bladder neck in patients with GSI as compared to normal women, while the urethral pressure was significantly decreased all along the urethra. It is suggested that both mechanical weakness all along the urethra and decreased deformability of the urethral wall may be of pathophysiologic importance in GSI.