Correlation of Urethral Closure Pressure, Leak-Point Pressure and Incontinence Severity Measures

The aim of this study was to determine whether water perfusion maximum urethral closure pressure (MUCP) correlates with Valsalva leak-point pressure (LPP), and which of these best correlates with subjective and objective incontinence severity measures. Fifty-two women with previously diagnosed genuine stress incontinence (n= 46), or mixed incontinence with a minor and controlled urge component (n= 6), were assigned an incontinence status grade based on interview and diary review. These women then completed visually observed standing LPPs at 250 ml bladder capacity, supine water perfusion MUCP determinations, pad tests and quality of life questionnaires. The urodynamic and severity measures were compared with correlation analysis or analysis of variance. A modest correlation exists between LPP and MUCP (r= 0.50–0.62, P<0.001). Both MUCP and LPP demonstrated significant decreases (P<0.01) with increasing severity of assigned incontinence grade. A very low and insignificant correlation existed for these urodynamic parameters and pad loss or quality of life measures. MUCP and LPP correlate modestly with each other and both are comparable in predicting incontinence severity. Either can be used as the urodynamic measure to assess intrinsic sphincter deficiency.     

Is the leak point pressure alone an accurate indicator of intrinsic sphincteric deficiency?

The aim of this study was to determine the characteristics of women who meet the criteria for intrinsic sphincteric deficiency (ISD) on maximum urethral closure pressure (MUCP) but not on leak point pressure (LPP) measurement. We performed a cross-sectional chart review of every patient who underwent multichannel, microtransducer urodynamic testing in our center between 1994 and 1996 (n=423). From this population we culled a sub-population of women who fit into one of the following two groups: women with no evidence of ISD on MUCP or LPP and women with evidence of ISD on MUCP only. Logistic regression was used to identify independent predictors of group membership. Increasing age (>60.5 years) and a positive supine empty stress test were the only independent predictors of membership in the group of women with ISD on MUCP only. Knowledge of these risk factors may help clinicians in choosing appropriate pre-operative testing.Abbreviations ISD Intrinsic sphincteric deficiency - LPP Leak point pressure - MUCP Maximum urethral closure pressure Editorial Comment: Valsalva leak point pressures and maximum urethral closure pressures are two different tests that can be used to evaluate and quantify urethral sphincteric function. The authors performed a cross-sectional study to determine the characteristics of women whose diagnosis of ISD would be missed based on an abnormal MUCP defined as <20 cm H₂0 if only a LPP was assessed. They found that of 305 patients with a normal LPP defined as >60 cm H₂0, 288 patients also had a normal MUCP (Group A) compared to 17 patients who had an abnormal MUCP (Group B). In comparing 18 patients characteristics, they found that age greater than 60 years and a positive supine empty stress test were independent risk factors for membership in Group B. It is known that both MUCP and LPP are fraught with variables making each difficult to standardize and validate. One could question whether a MUCP with a cutoff <20 cm can truly be used to define ISD. This brings up a related criticism described as a limitation by the authors—mainly that LPP were measured only at a bladder volume of 150 cc. Perhaps if the measurements were repeated at a larger bladder volume, there would have been an even greater correlation between MUCP and LPP. More needs to be done in the future to better standardize tests used to evaluate urethral function. As the authors mentioned, however, with the success of suburethal slings for all types of stress incontinence, perhaps this is a moot point.     

Weak VLPP and MUCP correlation and their relationship with objective and subjective measures of severity of urinary incontinence

The aims of the present study were to find the correlation between Valsalva leak-point pressure (VLPP) and cough leak-point pressure (CLPP) and to determine whether the water perfusion maximum urethral closure pressure (MUCP) correlates with VLPP. Seventy-nine women with previously untreated stress urinary incontinence were recruited to participate in a clinical study. Their mean age was 56.4 years, mean BMI was 27.8, and mean parity was 1.9. The mean values of VLPP and CLPP were 50.4 and 52.9 cm H₂O, respectively. We did not find statistically significant differences in the mean values of VLPP and CLPP. The mean value of MUCP at rest was 44.2 cm H₂O and the mean value of MUCP during maximal Valsalva maneuver was 37.2 cm H₂O; with 500 ml of sterile saline in the bladder the difference between them is statistically significant. In the study group (n=79), 56 patients (77%) had low VLPP (≤60 cm H₂O), 21 patients (30%) had low MUCP (≤30 cm H₂O), and 8 patients had MUCP≤20 cm H₂O (all at rest). Of the 56 patients with low VLPP, 16 also had a low MUCP (≤30 cm H₂O). This study mainly compares two parameters—the MUCP and the VLPP. Based on our results we can conclude that there is no correlation between these parameters. MUCP measures urethral resistance at rest and VLPP measures urethral resistance during increased intra-abdominal pressure (Valsalva maneuver). This work was supported by the Grant Agency of the Ministry of Health of the Czech Republic, grant NH 7378-3.     

Relationship of urethral retro-resistance pressure to urodynamic measurements and incontinence severity

AIMS: The urethral retro-resistance pressure (URP) is a retrograde urethral pressure profile measured by a new urodynamic measurement system.1GYNECARE MoniTorr Urodynamic Measurement System (ETHICON, Inc., Somerville, NJ). URP is the pressure required to achieve and maintain an open sphincter. This clinical investigation focused on a comparison of URP to standard urodynamic measurements and an examination of their relationship to incontinence severity. METHODS: Twenty-two centers enrolled 258 stress incontinent women in a randomized, crossover study of two groups: (1) test procedure followed by multichannel urodynamics, (2) multichannel urodynamics followed by test procedure. We defined incontinence severity categories using 24 hr urine loss and assessed these categories using incontinence quality of life (I-QOL), urinary incontinence severity score (UISS), incontinence visual analogue score (VAS), URP, maximum urethral closure pressure (MUCP), and leak point pressure (LPP). RESULTS: The mean age was 56.2 (+/-12) years. No order effect was present. The correlation coefficient between URP and MUCP was 0.31 (95% CI 0.19-1, P < 0.0001); between URP and LPP was 0.28 (95% CI 0.12-1, P = 0.003); and between MUCP and LPP was 0.14 (95% CI-0.04-1, P = 0.101). The mean values for URP across symptom severity categories were significantly different (P = 0.028) and decreased with increasing severity. The mean values for MUCP and LPP did not decrease with increasing severity. CONCLUSIONS: The study demonstrated that URP had a consistent relationship with incontinence severity. The data suggested that URP is a physiological measure of urethral function and may have clinical utility as a diagnostic tool. Future outcomes-based research is necessary to establish the predictive value of URP, MUCP, and LPP measurements in terms of incontinence cure rates and diagnosis of sphincter dysfunction.     

Urethral resistance measurement: a new method for evaluation of stress urinary incontinence in women

The aim of this study was to evaluate a new method to measure urethral resistance among 66 women with urinary incontinence. A stainless steel sphere attached to a guide wire was developed. The sphere is inserted into the bladder and withdrawn through the urethra at a steady rate. Serial measurements with spheres of 5, 6 and 7 mm were performed. The mean urethral resistance as measured by the largest sphere (0.07±0.03) was significantly greater than that measured by the medium sphere (0.06±0.02, p<0.0001), which was significantly larger than that measured by the smallest sphere (0.04±0.01, p<0.0001). There was good correlation of urethral resistance with maximum urethral closure pressure (MUCP) by this technique, but no correlation with Valsalva leak point pressure (VLPP).Editorial Comment: This study attempts to demonstrate the validity and reproducibility of measuring maximum urethral resistance. Further studies will need to be performed to see if this technique will be clinically useful, i.e., comparing values in continent and incontinent women, old vs. young population, etc. There is a need to better test to measure urethral function than leak point pressure and urethral pressure profile/MUCP     

Leak-Point Pressure: Clinical Application of Values at Two Different Volumes

A prospective analysis of 306 consecutive patients with genuine stress incontinence was performed to evaluate the clinical usefulness of additional leak-point pressure (LPP) determination at 200 ml. LPP values at both volumes were compared to maximal urethral closure pressure (MUCP) in an attempt to determine a critical cut-off value for the detection of a low MUCP (≤20 cmH₂O). A positive LPP at 150 ml was found in 157 patients. The mean LPP for patients with a low MUCP was 58.5 cmH₂O compared to 71.6 for those with a normal MUCP, which was statistically significant (p = 0.01). The correlation coefficient between LPP and MUCP was 0.317. A negative LPP was found in 30% (24/79) of the total having a low MUCP. The addition of values for LPP at 200 ml resulted in an increase in the number who leaked to 191, a 50% increase in the detection rate of low MUCP and a statistically significant relationship between LPP ≤60 cmH₂O and low MUCP. Various critical cut-off values for LPP demonstrated good specificity but poor sensitivity for the detection of a low MUCP. It was concluded that there was a statistically significant relationship between LPP and MUCP. Performing LPP at 200 ml provides additional clinically useful diagnostic information.     

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。     

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.     

Effect of voluntary attention on urethral pressure

We have systematically and simultaneously recorded vesical pressure and maximum urethral closure pressure (MUCP) in 109 women consulting for urinary incontinence over an extended period of time. During the recording, we asked them to peform a mental calculation (MC) test and other tests designed to induce an effort of voluntary attention. We found a significant increase in MUCP during the MC. At rest, 57 women displayed urethral pressure variations (UPV) higher than 15 cm H₂O. MC inhibited UPV in 80% of these cases. Such variations have never yet been reported. The effect of MC can be compared to an orienting reaction, which normally increases the sympathetic tonus. The role of the smooth and striated muscle fibers of the urethra, in the observed changes in urethral pressure, is discussed in light of the literature data.     

Clinical and urodynamic features of intrinsic sphincter deficiency

AIMS: A prospective analysis of 92 patients with genuine stress incontinence was performed to identify the clinical and urodynamic features of intrinsic sphincter deficiency (ISD). METHODS: We divided the patients into two categories: 50 patients affected by pure ISD as they had severe stress incontinence and no urethral mobility; 42 patients suffering from stress urinary incontinence without ISD as they had mild stress incontinence and marked urethral hypermobility. Cystometry was normal in all patients. The presence/absence of ISD was considered the dependent variable and was correlated against the following independent variables: age, vaginal deliveries, menopause, previous urogynecological surgery and/or hysterectomy, supine stress test, irritative and/or obstructive symptoms, Valsalva leak point pressure (VLPP), maximum urethral closure pressure (MUCP), urethral functional length (UFL), and leakage during cystometry. RESULTS: The statistical analysis showed close correlations between ISD and age (P < 0.001), menopausal status (P < 0.001), previous surgery (P < 0.0001), supine stress test (P < 0.0001), leakage during cystometry (P < 0.001), and UFL (P < 0.01). The VLPP was below the cut-off value (相似文献   

Value of urethral pressure profilometry in the female incontinent patient: a prospective trial with an 8-channel urethral catheter

Objectives. To measure the pressure profiles at different positions of the urethral circumference simultaneously.Methods. Twenty-two women with symptoms of genuine stress incontinence underwent urogynecologic assessment and multichannel urethral pressure profilometry (UPP) at rest with a specially designed 8-channel urethral catheter with radial openings.Results. The distribution pattern of maximum urethral closure pressure (MUCP) and functional urethral length (FUL) values were significantly different (P = 0.004 and P = 0.0004, respectively). Most of the highest MUCP values per patient were found between channels 2 and 4 (P = 0.015); most of the greatest FUL values per patient were found between channels 3 and 4 (P = 0.15).Conclusions. The data of our study substantiate asymmetric radial pressure distribution within the urethra and underline the necessity of cautious interpretation of results of conventional single-channel UPP, which might vary because of transducer orientation.     

Effect of occluding the urethra while recording urethral stress profile

The correlation between clinical and tonometric incontinence is frequently poor, with urethral profile results that do not correspond to clinical reality. Among potential causal factors, we have attempted to determine the importance of the absorption of kinetic energy from the mass of urine driven against the urethral captor (the hydraulic ram effect). Twenty patients (average age 50 +/- 10 years, para 2) suffering from genuine stress urinary incontinence, underwent urodynamic investigation with a constant air-flow pneumatic catheter equipped with two captors separated by an inflatable cuff located just above the urethral captor to block the inrush of urine into the urethra. After cystometric examination had excluded an unstable bladder, two urethral profiles were registered successively, first with cuff deflated, and then with cuff inflated. The values for urethral functional length (FL) and transmission factor (TF) show no significant changes. The values for the maximal urethral closing pressure (MUCP) were significantly lower in the second profile (cuff inflated) in 18 of 20 cases (average decrease 7 cm H2O), which corresponds to 14 percent of the average MUCP measured during the first profile (cuff deflated). The depression quotient increased from an average 0.80 to 1.05 from first to second profile. This study allows quantification of the urethral "hydraulic ram effect" which modifies determination of the MUCP during registration of urinary stress profile.     

Rotational differences in urethral pressure in incontinent women

Urethral pressure profile measurements are made by means of microtransducers at four different positions in the urethra (anterior, posterior, left and right side). The maximum urethral closure pressure (MUCP) is always highest in the anterior position in stress as well as in urge incontinent women. The functional urethral length shows no differences in the four positions. In all positions the recorded pressures and urethral length are higher in the urge incontinent group than in the stress incontinent group. A decrease of MUCP with age is observed in both groups.     

The relationships of urethral and pelvic floor muscles and the urethral pressure measurements in women with stress urinary incontinence

OBJECTIVES: To investigate the relationships between urethral and paraurethral anatomy and urethral pressure measurements in women with stress urinary incontinence (SUI). MATERIALS AND METHODS: A total of 83 women with SUI and 33 with frequency urgency syndrome but not SUI were included in the study. The parameters of transrectal sonography of the urethra and urethral pressure profilometry were compared among the subjects with each of four types of SUI and non-SUI subjects. RESULTS: Videourodynamic study revealed that 26 women had type 0 SUI, 39 had type 1 SUI, 19 had type 2 SUI and 9 had type 3 SUI. The urethral striated muscular area was significantly smaller in subjects with type 3 SUI than in subjects with type 0 SUI and in non-SUI subjects. The thickness of the urethropelvic ligaments was thinner in subjects with SUI than in non-SUI subjects. Maximal urethral closure pressure (MUCP) was also significantly smaller in subjects with SUI than in non-SUI subjects. Pressure transmission ratio (PTR) was lower in subjects with type 1, 2 and 3 SUI than in subjects with type 0 SUI and no SUI. Pelvic floor contractility was significantly lower for subjects with type 3 SUI than for the other groups of subjects. Leak point pressure (LPP) showed a significantly progressive decrease from type 1 to 3 SUI subjects. CONCLUSIONS: This study found that SUI in women is a condition in which the urethral and paraurethral structures become progressively deficient. The intrinsic and extrinsic structural deficiencies result in a lower MUCP, smaller PTR, insufficient pelvic floor contractility on the urethra, and a lower LPP in SUI patients.     

Comparison of preoperative and postoperative pressure transmission ratio and urethral pressure profilometry in patients with successful outcome following the vaginal wall patch sling technique

AIMS: We studied preoperative and postoperative pressure transmission ratio (PTR) and urethral pressure profilometry in patients undergoing the vaginal wall patch sling technique as a first surgical approach for genuine stress incontinence (GSI) with urethral hypermobility. The specific aims were to determine the exact urodynamic parameters, if any, that may be improved postoperatively and to report the urodynamic outcome of the vaginal wall patch sling technique in successful cases. METHODS: Preoperatively, all patients had a positive standing stress test, urethral hypermobility on Q-tip testing, and normal postvoid residual volume. On urodynamics, all patients had equalization of maximum urethral closure pressure (MUCP) on cough profilometry, and absence of detrusor contractions on subtracted cystometry. The PTR for each cough was calculated. Cough spikes were assigned locations in the first, second, third, or fourth quartile of the functional urethral length (FUL). Urethral pressure profilometry was performed at bladder capacity in the sitting position. All urodynamic tests were repeated 3-6 months postoperatively. A two-tailed t-test was used for statistical analysis. RESULTS: Forty-eight patients demonstrated successful outcome at initial follow up and constituted the study population. There was a statistically significant increase in MUCP at stress as well as a statistical increase in PTR in the first, second, and third quartiles of the FUL postoperatively. CONCLUSIONS: The vaginal patch sling technique appears to restore continence both by buttressing the urethra at times of stress as well as repositioning the proximal urethra into the intra-abdominal pressure zone, thus, enhancing pressure transmission to the proximal urethra.     

The Urethral Pressure Profile and Ultrasound Imaging of the Lower Urinary Tract

In a prospective study 105 patients with symptoms of stress incontinence underwent videourodynamic testing, including resting urethral pressure profilometry and translabial ultrasound. The urethral pressure profile (UPP) included maximum urethral closure pressure (MUCP), functional length (FL) and area under the curve (AUC). Ultrasound parameters included urethral thickness, urethral rotation and bladder neck descent, as well as funneling/opening of the internal urethral meatus on Valsalva maneuver. Levator contraction strength was assessed measuring the cranioventral displacement of the internal meatus. Negative correlations between UPP data and age, parity and previous surgery were observed which were consistent with literature data. There was a positive correlation between the urethral AP diameter on ultrasound and the MUCP, which agrees with reports showing reduced sphincter thickness or volume in stress-incontinent women. Hypermobility on ultrasound did not correlate with UPP data. However, a lower MUCP correlated with extensive opening of the bladder neck. Finally, there was a trend towards poorer pelvic floor function with lower MUCP measurements.     

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     

Noninvasive quantitative method for measuring isovolumetric bladder pressure and urethral resistance in the male: I. Experimental validation of the theory

Noninvasive measurement of intravesical pressure, impulsive flow rate, and localized urethral resistance is achieved by clamping the penis immediately above the glans with a pneumatic cuff and then instructing the patient to initiate voiding. The cuff is then deflated slowly until urinary flow of at least 1 ml/s is detected and is then released rapidly to permit unimpeded flow. Cuff pressure, voided volume, and flow rate are recorded as functions of time. From the resulting tracings it is possible to determine the isovolumetric bladder pressure, the impulsive flow rate, and the flow pattern specific to the test. We studied 53 male patients demonstrating that data thus obtained are reproducible and that the cuff pressure at the initiation of voiding does measure the bladder pressure at this moment. We then modeled the lower urinary tract by an analog electrical circuit which facilitated the analysis of the urodynamic data. This analysis suggests that if is possible to separate the effects of bladder dysfunction from the effects of urethral resistance and to localize the resistance to the proximal or distal urethra without invasive testing. © 1995 Wiley-Liss, Inc.     

Comparison of measurements obtained with microtip and external water pressure transducers

The aim of this study was to compare pressure readings obtained with catheter-mounted microtip and external water pressure transducers using a mechanical model for vesical pressure during Valsalva straining and coughing. The two catheter-mounted pressure transducers were simultaneously placed in a vinyl IV bag designed to mimic the parameters of the human bladder to allow comparison of simultaneous readings from both transducers. Simulated cough and Valsalva maneuvers of various strengths at different volumes (100 ml, 200 ml, 300 ml) were performed and the pressure readings generated by the two systems compared. The Pearson correlation coefficient between the systems was 0.998 for coughs and 0.998 for Valsalva efforts. Data were also analyzed by volume and strength of simulated cough and Valsalva effort, and correlations were found to be high (0.940) for all subgroup analyses. Mean absolute differences between events recorded by the two systems were small, as indicated by the y-intercept of 3.76 cmH₂O pressure. Neither transducer recorded consistently higher pressures than the other. We concluded that there is a high correlation between pressure measurements obtained from microtip and external water pressure transducers during simulated cough and Valsalva efforts in this model. As similar correlation should exist in vivo, urodynamic data generated by the two transducer types should be comparable.Abbreviations ISD Intrinsic sphincter deficiency - LPP Leak-point pressureEditorial Comment: There are many technical variations in urodynamic testing, including the type of catheter used. These authors found that results obtained with perfusion and microtip catheters were highly correlated. As would be expected, they were able to demonstrate a time lag in the pressure recordings from perfusion catheters. As a result of this lag the amplitude of a cough leak point might be underestimated by a perfusion catheter. However, their results suggest that the magnitude of this underestimation would not be clinically relevant. In summary, this paper suggests that the pressures measured by microtip catheters and perfusion catheters are similar. It remains to be seen whether these results can be replicated in vivo.     

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.