Mean Urethral Pressure Research Articles

The use of autologous skeletal muscle-derived cells as a sling in the treatment of stress-induced urinary incontinence: An experimental study in dogs

PurposeThis is an experimental preclinical study testing the applicability of autologous skeletal muscle-derived cells as a treatment of SUI in a canine model.MethodsTen mongrel dogs were included in this study. Skeletal muscle was harvested for biopsy in 4 dogs. One month later, incontinence was induced in 8 dogs through urethrolysis. Biopsied muscle cells were incubated and expanded for 8 weeks. Muscle-derived cells were collected and covered with a polyglycolic acid (PGA) scaffold immersed in culture medium and coated with Matrigel to be used as a sling, which was placed suburethrally in 8 dogs; 4 had cell seeding, and 4 had scaffolds only. Urethral pressure (UP) measurements were performed at baseline and 2 & 6 weeks after sling insertion. The urethra was harvested 4 weeks after sling insertion for histopathology.ResultsOne month, a statistically significant increase of mean urethral pressure values compared to baseline was observed in all dogs with a scaffold inserted. The increase ranged from 5 to 40 cmH2O. Histopathology showed significant periurethral proliferation of skeletal muscles in 4 dogs with cell-seeded scaffolds. These levels were the maximum levels in dogs # 1 & 2. This was not the case in the 4 dogs that had slings only.ConclusionBased on the outcome of this preliminary experience, the use of skeletal muscle-seeded PGA scaffolds seems to be an easy and reproducible procedure which preserves histological differentiation and integrity in a canine model

How Does the Urethra Respond to Bladder Filling in Continent and Incontinent Women?

The objective of this study was to describe mean urethral pressure (MUP) during filling cystometry in continent and incontinent women. Incontinent women were recruited from a urogynecology clinic if they answered "sometimes" or "always" to 1 of the items on the Medical, Epidemiologic, and Social Aspects of Aging questionnaire. Participants were categorized by Medical, Epidemiologic, and Social Aspects of Aging scores into stress urinary incontinence (SUI) or urgency urinary incontinence (UUI) groups. Continent women were recruited from the community. Multichannel urodynamics were performed using microtip catheters. Urethral pressure profiles were obtained with an empty bladder and at 100-mL increments during filling. Data were analyzed in SPSS. Continuous variables were compared with independent t test or analysis of variance, categorical variables with the χ2 test, and multivariable comparisons were made with linear regression. Eighty-six women (30 continent, 56 incontinent: 37 SUI, 19 UUI) with a mean ± SD age of 48 ± 15 years and a body mass index (BMI) of 31 ± 9 participated. Sixty-nine percent were White, 43% were postmenopausal, and 80% were parous. Continent women were younger (P < 0.001) and had a lower BMI (P = 0.004). Mean cystometric capacity was higher in women with SUI and continent women than in women with UUI (430 ± 142, 448 ± 101, and 332 ± 160, P = 0.04). Continent women had higher MUP at baseline when controlling for age, BMI, and parity (84 ± 35 cmH2O vs 62 ± 28 cmH2O; aR2 = 0.2, P = 0.02) compared with incontinent women. During filling, MUP in continent women was 20-30 cmH2O higher at all bladder volumes than incontinent women. Mean urethral pressure increased significantly between baseline and 300 mL in continent women (P < 0.005) and women with SUI (P = 0.04), but not in women with UUI (P = 0.48). Continent women have greater baseline MUP and greater increases in MUP during bladder filling than incontinent women.

Urethral Pressure Measurement as a Tool for the Urodynamic Diagnosis of Detrusor Sphincter Dyssynergia.

PurposeTo describe a technique for urodynamic diagnosis of detrusor sphincter dyssynergia (DSD) using urethral pressure measurements and examine potential associations between urethral pressure and bladder physiology among patients with DSD.MethodsMultiple sclerosis (MS) and spinal cord injured (SCI) patients with known DSD diagnosed on videourodynamics (via electromyography or voiding cystourethrography) were retrospectively identified. Data from SCI and MS patients with detrusor overactivity (DO) without DSD were abstracted as control group. Urodynamics tracings were reviewed and urethral pressure DSD was defined based on comparison of DSD and control groups.ResultsSeventy-two patients with DSD were identified. Sixty-two (86%) had >20 cm H2O urethral pressure amplitude during detrusor contraction. By comparison, 5 of 23 (22%) of control group had amplitude of >20 cm H2O during episode of DO. Mean duration of urethral pressure DSD episode was 66 seconds (range, 10–500 seconds) and mean urethral pressure amplitude was 73 cm H2O (range, 1–256 cm H2O). Longer (>30 seconds) DSD episodes were significantly associated with male sex (81% vs. 50%, P=0.013) and higher bladder capacity (389 mL vs. 219 mL, P=0.0004). Urethral pressure amplitude measurements during DSD were not associated with significant urodynamic variables or neurologic pathology.ConclusionsUrethral pressure amplitude of >20 cm H2O during detrusor contraction occurred in 86% of patients with known DSD. Longer DSD episodes were associated with larger bladder capacity. Further studies exploring the relationship between urethral pressure measurements and bladder physiology could phenotype DSD as a measurable variable rather than a categorical observation.

Retrograde ejaculation occurs in the dog, but can be prevented by pre-treatment with phenylpropanolamine: A urodynamic study

Retrograde ejaculation is partial or total propulsion of semen from the posterior urethra into the urinary bladder; it is well characterized (and relatively common) in humans, with only a few reports in animals. Our objectives were to determine whether retrograde flow of semen occurred during ejaculation in mature dogs with normal fertility, and to determine the effects of phenylpropanolamine on this phenomenon (dose-titration, switch-back study). Retrograde ejaculation and urethral pressure profile measurements were evaluated (double-blind) in six dogs after 5 days of oral treatment with phenylpropanolamine (0, 2, 4, or 8 mg/kg); all dogs received all treatments (at 2-week intervals). The number of sperm in the urine was determined before and after each manual sperm collection. Urethral pressure profiles were obtained three times during each procedure. In the absence of phenylpropanolamine, sperm were present in the bladder after semen collection in all dogs (number varied significantly among individuals). The mean (±S.D.) number of sperm in the bladder was 17.0 ± 5.0, 18.5 ± 1.2, 5.1 ± 5.0, and 4.8 ± 0.1 × 10 6 sperm for 0, 2, 4, and 8 mg/kg, respectively (no significant difference between dogs given 4 or 8 mg/kg, but both were significantly lower than those given 0 or 2 mg/kg). This reduction was significantly correlated to the increase in mean urethral pressure at the level of the sphincter (39 cm versus 59 cm H 2O in placebo-treated dogs versus those given 8 mg/kg). In conclusion, we confirmed that retrograde ejaculation occurred during the ejaculatory process in normal dogs, and we demonstrated that phenylpropanolamine (4 or 8 mg/kg once daily for 5 days before collection) increased urethral pressure and reduced the number of sperm voided into the bladder during ejaculation.

Urethral pressure response patterns induced by squeeze in continent and incontinent women

Our aim was to compare the urethral pressure response pattern to pelvic floor muscle contractions in 20-27 years old, nulliparous continent women (n = 31) to that of continent (n = 28) and formerly untreated incontinent (n = 59) (53-63 years old) women. These women underwent urethral pressure measurements during rest and repeated pelvic muscle contractions. The response to the contractions was graded 0-4. The young continent women showed a mean urethral pressure response of 2.8, the middle-aged continent women 2.2 (NS vs young continent), and the incontinent women 1.5 (p < 0.05 vs middle-aged continent, p < 0.001 vs young continent). Urethral pressures during rest were significantly higher in the younger women than in both groups of middle-aged women. The decreased ability to increase urethral pressure on demand seen in middle-aged incontinent women compared to continent women of the same age as well as young women seems to be a consequence of a neuromuscular disorder rather than of age.

Comprehensive urodynamics evaluation of 146 men with incontinence after radical prostatectomy

Objectives To assess the filling, storage, and voiding urodynamic parameters in a large group of men with urinary incontinence after radical prostatectomy. Methods We reviewed the videourodynamics testing results for 146 consecutive men referred for urinary incontinence after radical prostatectomy. Results The mean patient age was 69.0 years (range 48 to 85), and the mean interval since radical prostatectomy was 4 years (range 4 months to 19 years). All but four tests were performed more than 12 months postoperatively. Stress urinary incontinence (SUI) was demonstrated in 139 men (95%), with a mean abdominal leak point pressure of 59 cm H 2O. A statistically significant correlation was found between the leak point pressure and static urethral pressure profilometry measurements ( r = 0.46, P <0.0001). The mean urethral pressure profilometry measurements in those with SUI were significantly lower than in those without (46.6 versus 69 cm H 2O, P = 0.001). A total of 34 patients had diminished compliance or detrusor instability, but this was the sole finding in only 3. A hypocontractile detrusor response was seen in 49 patients, and 35 of these augmented voiding by abdominal straining. Patients with previous radiotherapy (n = 24) were more likely to have bladder outlet obstruction; the other parameters were similar to those in patients without radiotherapy. Conclusions Incontinence after radical prostatectomy is caused by intrinsic sphincter deficiency in the vast majority of patients. Urethral pressure profilometry measurements correlated with the severity of SUI, as measured by abdominal leak point pressure. Bladder outlet obstruction may coexist with SUI in a significant portion of patients. During voiding, a hypocontractile detrusor response may be seen, but the clinical significance of this finding is unclear.

Changes in urethral function with bladder filling in the presence of urodynamic stress incontinence and detrusor overactivity

The purpose of this study was to assess the effect of detrusor overactivity and bladder filling on urethral function with the use of urethral profilometry. Women with symptoms of urinary incontinence were recruited from our urodynamic clinic. All of the women underwent videocystourethrography and urethral pressure profilometry with the bladder empty and then full. The maximum urethral closure pressure, mean urethral pressure, functional urethral length, and pressure transmission ratios for each quartile were analyzed. Thirty-five women were recruited: 17 women had urodynamic stress incontinence, and 18 women had detrusor overactivity. In women with urodynamic stress incontinence, there was a significant increase in maximum urethral closure pressure and pressure transmission ratios over all quartiles when the bladder was full compared with empty. In women with detrusor overactivity, there was a significant decrease in functional urethral length and pressure transmission ratios in the second and third quartile of the urethral pressure profiles when the bladder was full compared with empty. Decreases in functional urethral length and pressure transmission ratios with bladder filling in those women with detrusor overactivity are at variance with the normal physiologic response to bladder filling, which suggests that urethral function is affected by the presence of abnormal detrusor activity and that the valid assessment of urethral function may not be possible if the detrusor overactivity is not treated.

Bladder-neck opening test in spinal cord injury patients using a new i.v. alpha-blocking agent, alfuzosin

A bladder-neck opening test using alfuzosin, a new alpha-adrenoceptor blocking agent, was carried out in 21 patients with spinal cord injury. The efficacy of alfuzosin was assessed with 4 simple urodynamic parameters: micturition, residual urine, posterior urethral pressure and diameter. Both mean urethral pressure and diameter were significantly affected after the administration of 5 mg i.v. alfuzosin. The test was clinically positive in 18 patients: 11 out of 13 patients using intermittent catheterisation or continuous drainage urinated and 6 out of 8 patients already tapping had reduced residual urine volumes. A decrease in posterior urethral pressure was also observed in 2 out of 3 patients who did not respond clinically to alfuzosin. Alfuzosin was well tolerated during this test. Oral alfuzosin should therefore be investigated in patients who gave a satisfactory response to such a test.

Experimental allergic encephalomyelitis: A neurourological study

To assess the neurourological disturbances produced by the perivascular inflammatory process in the acute phase of experimental allergic encephalomyelitis, we carried out a controlled study. Forty-six New Zealand male rabbits were inoculated with an encephalitogenic preparation. Twenty-seven of them developed neurological deficits in an average of 9.3 days postinoculation. A sample of 19 subjects was used as a control. The subjects were studied within 2 days after the manifestation of the first sign of encephalomyelitis. An average of eight successive cystosphincterograms were recorded. Their entire central nervous system was removed intact and suspended in 10% neutral buffered Formalin solution for 2 weeks, then cut into segments, embedded in paraffin, and finally stained with hematoxylin-eosin and Luxol Fast Blue. The results demonstrated a significant reduction of mean vesical capacity, maximum urethral pressure, and mean urethral pressure in the group with encephalomyelitis. Furthermore, we found a significant negative correlation between the average number of cellular perivasvular infiltrates in the spinal sacral segment and urethral pressures. The results showed a significant negative correlation between suprames-encephalic inflammation and mean vesical capacity.

Intraluminal Urethral Pressure Measurements In The Female Baboon: Effects Of Hormonal Manipulation

Four female baboons underwent cystometry and simultaneous urethral pressure profilometry (UPP) in a hypoestrogenic castrate state, after estrogen treatment, and after concurrent testosterone and estrogen treatment. Studies were performed under general anesthesia both before and after skeletal muscle paralysis. The results provide objective evidence that estrogen replacement enhances the urethral sphincter mechanism in the castrate female baboon by significantly increasing the paralyzed and nonparalyzed urethral length as well as the paralyzed total UPP area and the paralyzed UPP area to maximum urethral closure pressure (MUCP). The area increases reflected both the increase in functional urethral length as well as increases in mean urethral pressure. Muscle paralysis significantly reduced MUCP in all three hormonal states. The addition of testosterone had no significant effect on the UPP measurements. These findings are discussed in light of conflicting human studies regarding objective evidence for the role of hormonal modulation of urethral function and the role of estrogen therapy for stress urinary incontinence.