Increase In Urethral Resistance Research Articles

Urinary stress incontinence in men: diagnostic workup and modern surgical treatment

Radical prostatectomy is the most common cause of urinary stress incontinence in male patients. The exact pathophysiology is not clearly defined but probably due multifactorial. Thorough preoperative diagnostic workup before surgical therapy appears to be crucial for good postoperative results. Various systems are available. The artificial urinary sphincter continues to be considered standard procedure with ahigh success rate, even in patients with more complex situations and severe urinary incontinence. However, there are also relevant complication and revision rates. Modern alternatives include various sling systems. The adjustable sling systems consist of acushion that is placed against the urethral bulb and leads to apermanent increase in urethral resistance, which can be readjusted in different ways depending on the system implanted. The adjustable sling systems also seem to be an alternative in patients with aprior history of radiation therapy. The AdVance XP sling (Boston Scientific, Marlborough, MA, USA) is afixed sling that corrects the postoperative hypermobility of the posterior urethra after radical prostatectomy and, thus, leads to alonger functional urethral length. Good long-term results after AdVance XP implantation are only possible in selected patients.

Experimental study of therapy of bone marrow mesenchymal stem cells or muscle‐like cells/calcium alginate composite gel for the treatment of stress urinary incontinence

To explore the myoblast formation around the urethra and increase in urethral resistance of bone marrow mesenchymal stem cells or muscle-like cells/calcium alginate composite gel injection therapy and effect on LPP in SUI rat model. Isolation, cultivation, and identification of SD rat bone marrow mesenchymal stem cell were performed. 5-Azacytidine was introduced to induce muscle-like cells. SUI was produced in 72 6-week-old female Sprague-Dawley rats, which were divided into four groups: stem cell-gel group, muscle-like cell-gel group, Gel group, and mock control group. One, 4, and 8 weeks after injection, the leak point pressure (LPP) was measured. HE staining of Desmin and α-skeletal muscle actin (α-SMA) were performed. At 4 and 8 weeks after injection in stem cell-gel group and muscle-like cell-gel group, growth of blood vessels gradually increased at gel edge, BMSC, and muscle-like cells gathered around the new blood vessels observed by fluorescence tracer, muscle-like cells grew into elongated spindle-like cells, Desmin, and α-SMA staining were obviously positive expression. LPP determinations of the mock control group compared with the Gel groups were significantly different. Compound of BMSC, muscle-like cells, and calcium alginate composite gel has the potential to differentiate into muscle cells in the microenvironment of SUI rat model. It is found by LPP measurement that the correlation between the increase in urethral resistance and the volume effect of calcium alginate gel is high.

Increased urethral resistance by periurethral injection of low serum cultured adipose‐derived mesenchymal stromal cells in rats

To evaluate the effects of a periurethral injection of low serum cultured adipose tissue-derived mesenchymal stromal cells (LASC) and to develop a new autologous cell therapy for stress urinary incontinence. F344 rats were divided into three groups as based on the periurethral injection of LASC, GAX collagen or vehicle (control). At 2 and 4 weeks after injection, leak point pressure (LPP) was measured before and after transection of the pelvic nerves. For cell tracking, LASC of green fluorescent protein transgenic rats were injected into nude rats. At 2 weeks, both the LASC and collagen groups showed significantly higher LPP than the control group. At 4 weeks, the increase in LPP in the LASC group remained, whereas LPP in the collagen group decreased to baseline levels. In the absence of the urethral closure reflex after transection of the pelvic nerves, LPP in the LASC group was significantly higher than that in the other two groups. Histologically, the size of the urethral lumen was smaller in the LASC group than the collagen group. At 4 weeks, most of the LASC were positive for myogenic antigens including α-smooth muscle actin, desmin and calponin I. Periurethral injection of autologous LASC capable of myogenic differentiation made a greater contribution to the increase in urethral resistance than did the conventional collagen bulk injection. Thus, its use for treatment of stress urinary incontinence can be postulated.

Répercussions cliniques et urodynamiques du traitement de l’incontinence urinaire d’effort par bandelettes sous-urétrales transobturatrice

Analyse changes in voiding patterns after the treatment of female urodynamic stress incontinence (USI) with suburethral transobturator tape (TOT).Prospective study of 50 women with pure stress urinary incontinence treated between March 2004 and February 2006; mean age was 53+/-13 (34-87); parity was 2+/-0.75; mean follow-up was of 15 months (7-43). Each patient did a complete urodynamic examination and filled in two questionnaires (MHU and Contilife), before and three months after surgery.Cure rate was 94% (47/50). Three of 50 patients remained incontinent after surgery (6%). No peroperative complications occurred. Analysis of questionnaires showed that two clinical symptoms predominated postoperatively: dysuria (14%; n=7) and urgency (6%; n=3). Urodynamic profiles showed the following: a decrease in maximum flow rate from 23.6 to 18.9 ml/s (p<0.01), and an increase in urethral resistance from 0.12 to 0.23 (p<0.01). The number of patients with at least two Massey Abrams criteria defining obstruction rose from six to 19, while only seven patients had symptomatic dysuria. Quality of life improved significantly, from 2.32 to 4.63 (p<0.05).TOT is a safe, effective procedure with few complications. While urodynamic data show some obstruction, this has little impact upon clinical results or mid-term complications; it only mildly affects voiding and does not compromise patient satisfaction.

Influence of Urethral Sphincter Incompetence on Bladder Shape and Function in Myelodysplastic Children.

This study was undertaken to investigate the influence of the urethral function on bladder shape and function in myelodysplastic children. Of 39 myelodysplastic children, 30 were treated with intermittent catheterization. The diagnosis of internal sphincter incompetence (SI) was based on cystographic findings (open bladder neck) and that of external SI on urodynamic findings (underactive external sphincter identified on electromyography and maximum urethral closure pressure of less than 50 cm H2 O). Follow up included evaluation of bladder deformity and compliance. The mean observation period was 8.6 years. In the 11 patients with external SI, bladder deformity and compliance significantly improved as a result of intermittent catheterization. However, of 12 patients with overactive sphincter and/or closure pressure of 50 cm H2 O or more, eight showed deterioration or no improvement in bladder deformity, and three showed upper urinary tract deterioration. These results indicate that an increase in urethral resistance may lead to deterioration of bladder shape.

Combined pharmacokinetic and urodynamic study of the effects of oral administration of phenylpropanolamine in female Beagle dogs

This study investigated the differences in pharmacokinetic, urodynamic and haemodynamic parameters after administration of two dosages of phenylpropanolamine (PPA) in female Beagle dogs. Blood was collected and urethral pressure profiles were performed over 24 h periods following single or three times daily (T(0),T(6h),T(12h)) administration of PPA. The maximal concentration (C(max)) was reached 2 h after PPA administration (T(max)) and the half-life (T((1/2))) was 4 h. Three times daily administration induced an increase in C(max) due to bioaccumulation. A significant increase in urethral resistance, compared to the control group, was observed at T(max) after 1 week of once daily administrations, but not when PPA was administered every 6 h during the day, despite higher plasma concentrations following more frequent dosing. An increase in mean arterial pressure was compensated by a decreased heart rate. Clinical efficacy with the temporary increase in urethral resistance following single daily administration of PPA in dogs suffering from urethral sphincter mechanism incompetence (USMI) needs to be further investigated in a randomised clinical trial.

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

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. 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). 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 < or = 20 mL/s (P = 0.09) in preoperative UFM were more likely to require prolonged intermittent catheterization after surgery. 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 < or = 20 mL/s before surgery are risk factors for postoperative voiding difficulty.

Neue Verfahren zur operativen Therapie der postoperativen Belastungsinkontinenz beim Mann

The impact of minimally invasive techniques for the treatment of postoperative male incontinence has significantly improved in recent years. These techniques are based on the continuous increase in urethral resistance. This resistance can be readjusted with balloons placed paraurethrally or with readjustable suburethral slings. The success rates depend on the preoperative degree of incontinence. With bulking agents that are transurethrally injected into the submucosa of the sphincter, continence rates between 12 and 90% can be seen. Severe complications are rare. The impact of the studies is often limited due to a short follow-up. After implantation of adjustable balloons that are placed paraurethrally close to the bladder neck, continence rates up to 70% can be seen. The overall improvement of incontinence is observed in up to 90% of the treated patients. Complications such as balloon migration or mechanical disorders can cause operative revision. Suburethral sling systems are available as bone-anchored slings or as readjustable slings. Continence can be seen in up to 90% of the patients postoperatively. Severe complications such as sling erosion or sling infection are rare. In cases of mild and moderate incontinence, these minimally invasive techniques are good alternatives to the fascial sling or alloplastic sphincter implantation. To improve the evaluation and to compare these techniques with the conventional methods, further investigations with a longer follow-up are necessary.

Current management of stress urinary incontinence.

Pelvic floor muscle training (PFMT) is the most commonly recommended conservative therapy for women with SUI. PFMT is used to rehabilitate or strengthen the PFMs; it increases the ability to produce an increase in urethral resistance, provided the patient is able to perform a correct voluntary PFM contraction. It counteracts PFM weakness, increasing support for the urethra and bladder, and improves the tone of the PFMs, in particular the levatores ani. A patient-specific regimen should be established, depending on the status of the muscles. PFMT includes long, slow contractions at regular intervals and short, sharp ‘pull-ups’. The major drawback of this type of treatment is compliance, which is usually high upon initiation, but decreases over time. Combined therapy of PFMT and adjuncts like vaginal cones, biofeedback and electrical stimulation seems to have no additional benefit over PFMT alone, but might be useful for some women to learn how to perform a correct PFM contraction [4]. Weighted vaginal cones and electrical stimulation can also be used individually to improve the function of the PFMs.

Role of angiogenesis in bladder response to partial outlet obstruction

Benign prostatic hyperplasia (BPH) is a disease that has its etiology in the abnormal growth of the adult human prostate gland that accompanies the aging process in men. The symptomatic presentation of this disease, however, is related largely to degenerative changes in the bladder that occur as a result of the increasing urethral resistance and partial bladder outlet obstruction (PBOO) caused by the growing prostate gland. BPH is characterized by bladder hypertrophy, significant decreases in urinary flow and compliance, presence of residual urine after voiding, voiding urgency and incontinence (). Obstructed bladder dysfunction secondary to BPH is a slow, progressive disease that is so strongly associated with human aging that it is an expected occurrence of the male aging process. Although the symptoms of BPH are usually not life threatening, they effect an extremely negative quality of life for men who suffer from them. However, many men delay seeking medical treatment for early BPH since bladder function can remain relatively normal as the hypertrophying bladder initially compensates for the progressive increase in urethral resistance caused by prostatic obstruction. The limited changes in micturition pressure and flow characteristics that occur during compensated function are not usually disabling enough to motivate seeking medical attention, which, often, is not sought until the symptoms become typical of advanced disease. Recent advances in detection methods enable identification of patients with significant BPH during compensation before the bladder becomes dysfunctional (decompensated). A more complete understanding of the disease processes that underlie the loss of bladder function associated with BPH might enable the development of treatments that better protect these early-stage BPH patients from the more debilitating aspects of the disease. This review updates the understanding of obstructive bladder dysfunction via the use of animal models.

Voiding function after a modified no-tension pubovaginal sling

Voiding dysfunction following sling procedures for correction of genuine stress urinary incontinence (GSI) is a frequently reported complication. This study sought to determine if voiding dysfunction could be reduced by eliminating sling tension against the urethra. Participants were diagnosed with GSI and randomized to one of two surgical groups. One received a conventional suburethral sling and the other received a modified sling placed at the mid-urethra without tension. Voiding trials after surgery monitored for voiding dysfunction. Multichannel urodynamic studies were performed pre- and post-operatively. Cure rates for GSI were similar for the two groups (91.7 vs. 88.5%). The 27 patients in the modified group voided an average of 5 days earlier than the 21 patients in the conventional group. Conventional group patients were more likely to have urinary retention (125 vs. 49 cc, p=0.03). The modified group had a lesser change in average closure pressure following surgery. Results suggested a higher increase in urethral resistance in the conventional group (0.72 vs. 1.88 cm H2O ml(-2) sec2). No differences were seen in symptomatic urinary urgency or urge incontinence following surgery. This study demonstrated a no-tension sling at the mid-urethra to afford equivalent cure of GSI with significant reduction of voiding dysfunction.

Urodynamic evaluation of the human bladder response to an increase in outlet resistance.

We prospectively evaluated the response of the human bladder to a chronic increase in urethral resistance according to the indices of pressure, volume flow rate, total (external) bladder work, and maximum and average detrusor power. Six men with incontinence after radical prostatectomy were evaluated urodynamically before and 3-6 months after undergoing a bulbourethral sling procedure. None of the men suffered from significant obstructive or irritative voiding symptoms preoperatively. Urodynamic evaluation showed postoperative increases in both average detrusor pressure and pressure at maximum flow, but there were no significant changes in voided volume, void time, or postvoid residual urine volume. Maximum detrusor power, average detrusor power, and total (external) bladder work were all significantly increased. These data confirm that the human bladder possesses a functional reserve, which is elicited by an increase in urethral resistance.

CHANGES IN BLADDER CONTRACTILITY AND COMPLIANCE DUE TO URETHRAL OBSTRUCTION: A LONGITUDINAL FOLLOWUP OF GUINEA PIGS

Purpose: We established the longitudinal changes in bladder contractility and compliance as a result of urethral obstruction using a guinea pig model.Materials and Methods: Obstruction was induced in guinea pigs by a silver ring around the urethra. Urodynamic studies were performed longitudinally in individual animals. Bladder contractility and compliance were calculated from the measured bladder pressure and urine flow rate.Results: Bladder contractility developed in distinct phases. It reached a maximum 200% increase after an average of 3.25 weeks concomitant with an almost 2-fold increase in urethral resistance, remained 150% to 200% increased during weeks 4 to 7 and then decreased to starting levels again, while urethral resistance remained almost 2-fold increased. Bladder compliance decreased by 80% during the first 3 weeks and continued to decrease to 5% of its original value after 10 to 11 weeks.Conclusions: Our data indicate that as a result of obstruction bladder function passes through a specifi...

Changes in bladder contractility and compliance due to urethral obstruction: a longitudinal followup of guinea pigs.

We established the longitudinal changes in bladder contractility and compliance as a result of urethral obstruction using a guinea pig model. Obstruction was induced in guinea pigs by a silver ring around the urethra. Urodynamic studies were performed longitudinally in individual animals. Bladder contractility and compliance were calculated from the measured bladder pressure and urine flow rate. Bladder contractility developed in distinct phases. It reached a maximum 200% increase after an average of 3.25 weeks concomitant with an almost 2-fold increase in urethral resistance, remained 150% to 200% increased during weeks 4 to 7 and then decreased to starting levels again, while urethral resistance remained almost 2-fold increased. Bladder compliance decreased by 80% during the first 3 weeks and continued to decrease to 5% of its original value after 10 to 11 weeks. Our data indicate that as a result of obstruction bladder function passes through a specific sequence of stages, including first a compensatory increase in contractility, then a stabilization phase and finally a decompensation state. In contrast bladder compliance shows a continuous decrease. The data suggest that for assessing how far a bladder has deteriorated due to obstruction a combination of functional and structural data may be warranted.

Changes in urethral resistance after surgery for stress urinary incontinence

Seventy women with stress urinary incontinence underwent simultaneous voidingurethrocystometry using microtip transducers and an 8-channel recorder, before and three to twelve months after either the modified Bureh ( 48 70 ) or the modified Pereyra ( 22 70 ) retropubic urethropexy. Increase in urethral resistance ( p < 0.005) was more marked following the Pereyra procedure (0.042 ± 0.039 to 0.07 ± 0.061) and 30 percent experienced postoperative voiding difficulties, compared with the Bureh procedure (0.035 ± 0.029 to 0.055 ± 0.03) where 20 percent experienced postoperative voiding difficulties. Of those patients who voided without a detrusor contraction prior to surgery ( 35 70 ), in 50 percent a detrusor contraction component developed to their voiding mechanism postoperatively ( p < 0.05) and overcame the increased urethral resistance with no postoperative voiding difficulties. In the remaining 50 percent a detrusor contraction failed to develop during postoperative voiding and 90 percent of them demonstrated reduced flow rates and increased use of Valsalva maneuver, and needed prolonged postoperative bladder drainage prior to resumption of spontaneous voiding ( p < 0.005). Inability to develop a detrusor contraction during voiding in face of increased urethral resistance promoted by the incontinence surgery provided a suitable explanation for post surgery voiding difficulties in 20 to 30 percent of patients.

The Use of Rectus Fascia to Manage Urinary Incontinence

The surgical management of urinary incontinence in children is one of the most difficult challenges facing pediatric urologists today. We have critically looked at our experience using a rectus fascial sling to prevent incontinence. Eleven girls (6 to 22 years old) with urinary incontinence from neurogenic bladder dysfunction (9), surgical injury to the bladder (1) or urogenital sinus abnormality (1) comprise this study. All had failed regimens of pharmacological therapy and intermittent catheterization. Three patients had undergone prior bladder neck reconstruction and 2 an augmentation cystoplasty in an attempt to control the incontinence. Urodynamic studies revealed several reasons for the continued wetting in these individuals: a changing neurological lesion leading to a loss of innervation and concomitantly lowered urethral resistance in 2 patients, adequate urethral resistance at rest but decreasing resistance with bladder filling in 4, no increase in urethral resistance with increases in abdominal pressure in 4 and urethral instability (a decrease in resistance following a cough or Valsalva’s maneuver) in 1 apparently neurologically normal girl. Eight patients are dry 3 to 24 months postoperatively on intermittent catheterization. All have demonstrated either an increase in urethral resistance at rest or an adequate level of resistance during filling of the bladder or a sudden increase in abdominal pressure. Of the remaining 3 patients 1 is dry for 2 to 3 hours but then leakage occurs, 1 is improved but damp and 1 patient is wet 3 months postoperatively. The use of rectus fascia to improve outlet resistance seems to be a viable alternative in the management of incontinence in selected female subjects.

Urinary Retention Induced by Estrogen Injections in Mice: An Analytical Model

Daily subcutaneous injections of pharmacological doses of 17β-estradiol (E2, 0.4 μg.gm. body weight) resulted in significant urinary retention in the bladder of castrated mice. Although the urinary retention developed in both male and female mice, the increase in urethral resistance to urinary flow and the dilatation of posterior urethra were observed only in castrated male mice receiving E2 Histological changes common to male and female mice were cornification and stratification of urethral epithelium and fibrosis of connective tissues surrounding the urethra, suggesting that these changes may cause the urinary retention. Although the exact mechanism has not been defined, the urinary retention produced by the present method may be useful as a model of human disease.

Effect of Chronic Electrostimulation of the Sacral Roots on the Striated Urethral Sphincter

Chronic electrostimulation of the sacral roots induces an increase in urethral resistance due to activation of muscles of the striated urethral sphincter. Histochemical study of the urethral striated musculature (nonstimulated) revealed 3 main varieties of fibers: 1) Slow twitch fibers (35 per cent of the whole muscle); 2) Fast twitch fatiguable fibers (52 per cent); and 3) An intermediate type, fast twitch fatigue resistant (13 per cent).Ten dogs with chronically implanted electrodes at the 2nd sacral root were subjected to a program of prolonged stimulation under anesthesia. After prolonged electrostimulation, we detected hypertrophy of the striated muscle fibers of the urethra, anal sphincter and stimulated side of the tail. The stimulated muscle fibers showed a higher overall oxidative activity than the controls. This occurred both in intact and spinalized animals. We thus expect the urethral striated musculature to be more resistant to fatigue because of the increased oxidative activity. Stimulated fibers also had increased glycolytic activity as shown by the enhanced intermyofibrillar deposition, especially in the fast twitch fibers. The increased glycolytic activity may also increase fatigue resistance by producing energy during periods of low oxygen supply at the peak of muscular contraction. As a consequence of increase in oxidative and glycolytic capacities and muscular hypertrophy, we expect that the striated musculature of the urethra will be not only more resistant to fatigue but also capable of generating higher tension. Both are important in achieving continence via electrostimulation of sacral nerve roots. Approximately 3 months after conclusion of the stimulation program these changes had gradually reverted to the normal prestimulation level.

Combined Electromyography and Gas Urethral Pressure Profilometry Before and After Transurethral Resection of the Prostate

Combined electromyographic and gas urethral pressure profilometry was done on 10 consecutive patients before and 3 months after transurethral resection of the prostate. A significant reduction was found postoperatively in the functional urethral length, whereas the maximum urethral closure pressure remained unchanged. Increase in urethral resistance in prostatic obstruction of the posterior urethra was related to the increase in the functional length of the posterior urethra rather than to mechanical occlusion of the urethral lumen. Periurethral striated muscle activity was recorded from the membranous urethra to the urethrovesical junction with the maximal activity located in the membranous urethra. Marked striated muscle activity also was found consistently at the bladder neck.