Urethral Closure Pressure Profile Research Articles

Modified Urethral Graciloplasty Cross-Innervated by the Pudendal Nerve for Postprostatectomy Urinary Incontinence: Cadaveric Simulation Surgery and a Clinical Case Report.

An artificial sphincter implanted in the bulbous urethra to treat severe postprostatectomy urinary incontinence is effective, but embedding-associated complications can occur. We assessed the feasibility, efficacy, and safety of urethral graciloplasty cross-innervated by the pudendal nerve. A simulation surgery on three male fresh cadavers was performed. Both ends of the gracilis muscle were isolated only on its vascular pedicle with proximal end of the obturator nerve severed and transferred to the perineum. We examined whether the gracilis muscle could be wrapped around the bulbous urethra and whether the obturator nerve was long enough to suture with the pudendal nerve. In addition, surgery was performed on a 71-year-old male patient with severe urinary incontinence. The postoperative 12-month outcomes were assessed using a 24-hour pad test and urodynamic study. In all cadaveric simulations, the gracilis muscles could be wrapped around the bulbous urethra in a γ-loop configuration. The length of the obturator nerve was sufficient for neurorrhaphy with the pudendal nerve. In the clinical case, the postoperative course was uneventful. The mean maximum urethral closure pressure and functional profile length increased from 40.7 to 70 cm H 2 O and from 40.1 to 45.3 mm, respectively. Although urinary incontinence was not completely cured, the patient was able to maintain urinary continence at night. Urethral graciloplasty cross-innervated by the pudendal nerve is effective in raising the urethral pressure and reducing urinary incontinence.

Perfil de presión uretral

The “urethral pressure profile” is a graph indicating the intraluminal pressure along the length
 of the urethra and the “urethral closure pressure profile” is given by the substraction of
 intravesical pressure (pves) from urethral pressure (pura). Both aim to represent the ability
 of the urethra to prevent involuntary leakage of urine on efforts or exertion. The continuous
 measurement of pves also allows the detection of detrusor contractions. In this article we will
 refer to its terminology, the necessary equipment to carry it out, the examination technique,
 its morphology in women and men, and the stress urethral pressure profile in women. The
 most important parameter is the “maximum urethral closure pressure”, which is the maximum
 difference between pura and pves; a value ≤ 20 cm H2O participates in the urodynamic definition
 of intrinsic sphincter deficiency (together with an abdominal leak point pressure ≤ 60 cm H2O).
 However, it must be taken into account that the different techniques used for its measurement
 has led to inconsistent results, which makes their acceptance in clinical practice difficult.

PD01-03 VIDEOURODYNAMIC CHANGES AND THE PREDICTORS OF EARLY RECOVERY ON URINARY CONTINENCE AFTER LAPAROSCOPIC RADICAL PROSTATECTOMY

You have accessJournal of UrologyUrodynamics/Lower Urinary Tract Dysfunction/Female Pelvic Medicine: Incontinence: Evaluation (Urodynamic Testing)1 Apr 2016PD01-03 VIDEOURODYNAMIC CHANGES AND THE PREDICTORS OF EARLY RECOVERY ON URINARY CONTINENCE AFTER LAPAROSCOPIC RADICAL PROSTATECTOMY Hsu-Che Huang, Yuan-Hong Jiang, and Hann-Chorng Kuo Hsu-Che HuangHsu-Che Huang More articles by this author , Yuan-Hong JiangYuan-Hong Jiang More articles by this author , and Hann-Chorng KuoHann-Chorng Kuo More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2016.02.2023AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Although laparoscopic radical prostatectomy (LRP) is effective in treatment of localized prostate cancer, patients might suffer from stress urinary incontinence (SUI) after LRP. This study investigated the changes of videourodynamic parameters after LRP and impact on urinary incontinence METHODS A total of 48 male patients underwent LRP received videourodynamic study (VUDS) at baseline, 3 months and 6 months after operation. The changes of urodynamic parameters including detrusor pressure (Pdet), voided volume, cystometric bladder capacity (CBC), maximum flow rate (Qmax), postvoid residual (PVR), maximal urethral closure pressure (MUCP) and functional profile length (FPL) were measured at 3 and 6 months after opeation. The bladder neck (BN) level to the superior margin of the symphysis pubis (SMSP) after LRP was also measured 7 to 10 days after opeartion by retrigrade cystography. The BN level at or above SMSP was defined as 0, and BN level below SMSP more than 2 cm was defined as -2, otherwise, the BN level was -1. The SUI condition was evaluated by questionare during out-patient clinic follow up. RESULTS The overall SUI rate was 66.7%,47.9%, and 16.7% at 3,6,12 months after LRP, respectively. MUCP, FPL and Pdet significantly declined from 62.6cmH2O, 48.7mm and 41.8cmH2O, which was measured at baseline, to 46.4cmH2O,16.8mm and 25.4cmH2O at 6 months, respectively. Among patients with SUI at 3 months and 6 months after operation, the MUCP level at 3 months and bladder neck level were significantly lower than patients without SUI. For patients with prolonged SUI (12 months postoperatively), the MUCP at 3 months showed significant association. (Table.1 and Table. 2) CONCLUSIONS BN level and MUCP can strongly predict the early continence recovery after LRP. The BN level not below the symphysis pubis and higher MUCP level at 3 months after operation are associated with an early recovery of SUI after LRP © 2016FiguresReferencesRelatedDetails Volume 195Issue 4SApril 2016Page: e46 Advertisement Copyright & Permissions© 2016MetricsAuthor Information Hsu-Che Huang More articles by this author Yuan-Hong Jiang More articles by this author Hann-Chorng Kuo More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

CHARACTERISTICS OF STRESS URINARY INCONTINENCE AFTER PELVIC ORGAN PROLAPSE SURGERY.

(Objective) We examined the morphology and function of lower urinary tract in order to know characteristics of stress urinary incontinence after pelvic organ prolapse (POP) surgery. (Methods) One hundred twenty-five female patients (mean age 64.9 years, mean parity 2.2, mean body mass index (BMI) 24.4) were performed anti-incontinence surgery for stress urinary incontinence. Sixty-one of 125 patients underwent POP surgery before anti-incontinence surgery. They were divided into groups as follows: post-POP surgery group and non-POP surgery group. All patients underwent one-hour pad test, chain cystourethrography (chain CG), Urodynamic studies (UDS) as preoperative assessment. Midurethral sling procedure was performed as an anti-incontinence surgery. Preoperative assessment criteria and postoperative treatment results were compared between two groups. (Results) Post-POP surgery group showed a significantly greater amount of urinary leakage per 1-hour pad test than non-POP surgery group (65.2±74.3 g vs 14.3±25.2 g, p<0.05). The diagnosis of type III urinary stress incontinence (Blaivas' classification) was more frequently diagnosed in post-POP surgery group than non-POP surgery group (50.0% vs 25.0%, p<0.05). Maximum urethral closure pressure (MUCP) and functional profile length (FPL) of post-POP surgery group were lower than those of non-POP surgery group (27.4±9.2 vs 35.7±14.7, p<0.05, 27.3±4.7 vs 29.9±5.0, p<0.05). Postoperative treatment results of post-POP surgery group were worse than those of non-POP surgery group (78.7% vs 92.2%, p<0.05). (Conclusions) Post-POP surgery group showed more severe urinary incontinence, lower urinary function and lower cure rate. Therefore we should keep in mind when approaching urinary stress incontinence.

Urethral sphincter function before and after radical prostatectomy: Systematic review of the prognostic value of various assessment techniques

Urethral sphincter incompetence is generally considered to be the most important contributing factor to post-radical prostatectomy incontinence (PRPI). The value of various assessment techniques used to objectify urethral sphincter function before and/or after RP is unclear. Our review addresses the following questions: In men having to undergo RP, which measurement techniques that assess pre-operative and post-operative urethral sphincter function have predictive value for the post-operative continence status or correlate with the post-operative continence status. A systematic and comprehensive search was performed using the terms: urethral sphincter, radical prostatectomy (RP), and urinary incontinence. Results were restricted to English-language papers published between 1980 and March 2012. Only techniques described by at least two studies were included. Several assessment techniques for urethral sphincter function and anatomy were identified: sphincter electromyography, magnetic resonance imaging (MRI), perfusion sphincterometry and urethral pressure profilometry (UPP). A shorter urethral sphincter length on preoperative endorectal MRI might be associated with an increased risk of PRPI as well as longer time to achieve continence. UPP showed that both maximum urethral closure pressure (MUCP) and functional profile length (FPL) decrease significantly after RRP. Low preoperative MUCP and FPL are associated with an increased risk of PRPI. The other mentioned assessment techniques are not usable as preoperative diagnostic tools. MRI and UPP might be valuable preoperative diagnostic tools in patients waiting for RRP. However, more and larger studies are needed to show the exact role of MRI and UPP in the preoperative management of patients waiting for RRP and for whom post-operative incontinence is a big concern.

Correlation between clinical presentation and urodynamic findings in women attending urogynecology clinic

Introduction:Urodynamic studies objectively observe lower urinary tract function and dysfunction so that an appropriate treatment can be planned. In the present study, we tried to evaluate the role of urodynamic studies in the final diagnosis and management plan in patients attending an urogynecology clinic.Materials and Methods:This observational study was conducted in an urogynecology clinic. 202 women were included. After detailed history, pelvic examination and introital sonography these women were subjected to urodynamic study. During the filling cystometry detrusor activity, first desire to void and bladder capacity was recorded. This was followed by urethral pressure measurements, when functional urethral length, maximum urethral closure pressure and stress urethral pressure profile was recorded.Results:Most prevalent complaint was mixed urinary incontinence (33.17%), followed by stress incontinence (31.68%) and urge incontinence (13.37%). According to the standard urodynamic definition 66.33% were normal in the population studied. None of the urodynamic parameters individually or in combination were found to be very useful for establishing a diagnosis.Conclusion:Establishment of the final diagnosis of urinary incontinence and planning of management should be based on detailed history, physical examination, bladder diaries, and careful interpretation of urodynamic data. Urodynamic study; however, doesn’t seem to be imperative to establish a diagnosis in uncomplicated cases where symptoms and signs are reliable and correlating.

Urodynamic characteristics of the modified orthotopic ileal neobladder

Radical cystectomy is the method of choice in management of muscle invasive, organ-confined tumors of the bladder (T2-T4, N0-Nx). The most frequent continent orthotopic urinary diversion after radical cystectomy is the ileal neobladder. A modified technique consists of using a shorter segment of the terminal ileum than the standard technique, around 30 cm. The aim of this study was to determine the urodynamic characteristics of the orthotopic ileal neobladder created by a modified technique. In this prospective clinical study we analyzed the urodynamic parameters of 24 patients who had underwent radical cystectomy with orthotopic urinary diversion by ileal neobladder created using a modified technique. In all the patients we performed invasive and noninvasive urodynamic investigations 12 months after the operation. The urethral pressure profile parameters analyzed were maximal urethral pressure, maximal urethral closure pressure and the functional urethral profile length. The average age of the patients was 63 (49-73) years, 90% were males and 10% were females. The median length of the shorter segment of the terminal ileum was 28 (range 22-35) cm. Prior to enterocystometry and uroflowmetry postvoid residual (PVR) urine was measured by a urethral catheter. The median PVR was 16.7 (0-140) mL. The median enterocystometric capacity was 396 (range 372-532) mL. The median end filling pouch pressure was 27.6 (range 20-70) cmH2O. The median maximal flow of urine was 22.1 (range 9.7-39.5) mL/s and the average flow of urine was 9.61 (range 3.6-17.6) mL/s. Flow time in the analyzed group was 47.5 (range 22-119) s. The median maximal urethral pressure was 54 (range 12-101) cmH2O, maximal urethral closure pressure 36.6 (range 6-91) cmH2O. Functional urethral profile length was 14.9 (range 4-37) mm. An ileal orthotopic pouch created by a modified technique using a shorter segment of the terminal ileum after 12 months presents with urodynamic characteristics similar to the native bladder.

Lower urinary tract dysfunction in type 1 familial amyloidotic polyneuropathy in Kumamoto, Japan

To evaluate lower urinary tract dysfunction of type 1 familial amyloidotic polyneuropathy (FAP) patients in Kumamoto, Japan. Lower urinary tract symptoms were evaluated in FAP patients. Urodynamic studies were evaluated in FAP patients as compared to those in control subjects. The location and distribution of amyloid deposits were evaluated in the urinary bladder in an autopsy case. In lower urinary symptoms, 86%, 19% and 38% patients showed difficulty in urination, urinary frequency and urinary incontinence. In detrusor function during filling cystometry, 14% patients showed detrusor overactivity. Moreover, 43% patients showed low compliance bladder, 62% and 38% patients showed normal and reduced bladder sensation, respectively. First desire to void (FDV), strong desire to void (SDV) and post-voided residual urine (PVR) were increased in FAP patients as compared to those in control subjects. In the urethral pressure profilometry, 71%, 10% and 19% patients showed incompetent, normal functional and overactive urethral closure mechanism, respectively. Maximum urethral pressure (MUP), maximum urethral closure pressure (MUCP) and functional profile length (FPL) were decreased in FAP patients compared to those in control subjects. Autonomic, somatic nerve systems and bladder detrusor musculature might be impaired in lower urinary tract of type 1 FAP patients in Kumamoto, Japan.

Urodynamic and morphologic changes in the lower portion of the urogenital tract after administration of estriol alone and in combination with phenylpropanolamine in sexually intact and spayed female dogs

To compare the urodynamic and morphologic effects of the administration of estriol alone and in combination with phenylpropanolamine on the lower portion of the urogenital tract in female dogs. 3 sexually intact and 3 spayed female Beagles without urinary incontinence. Dogs received estriol (2 mg, PO) once daily for 7 days followed by estriol (2 mg, PO) and phenylpropanolamine (1.5 mg/kg, PO) once daily for 7 days. Urethral pressure profilometry, diuresis cystometry, and vaginourethrography were performed before treatment (day 0) and at days 7 and 14. The maximum urethral pressure (MUP) and closure pressure (MUCP), urethral functional and anatomic profile lengths, integrated pressure (IP), plateau, distance before MUP, maximum meatus pressure, threshold pressure, threshold volume, compliance, urethral length, and vaginal length and width were measured. Before treatment, no urodynamic differences were observed between the 2 groups; however, vaginal length and width were significantly shorter in spayed dogs. Compared with day 0 values, estriol treatment significantly increased MUP, MUCP, and IP values at day 7, but at day 14, this effect decreased despite phenylpropanolamine administration. No morphologic changes from baseline were detected after either treatment in any dog. Data suggest that estriol mainly acts on the urethral sphincter mechanism by increasing urethral resistance in sexually intact and spayed female dogs without urinary incontinence. Administration of estriol and phenylpropanolamine did not increase the urethral resistance more than estriol alone. The urodynamic effects of estriol in female dogs with urinary incontinence remain to be elucidated.

Comparison of microtransducer and fiberoptic catheters for urodynamic studies

OBJECTIVE: To assess the validity and reproducibility of a fiberoptic transducer urodynamic catheter for urethral closure pressure profiles and leak point pressure determination, using a microtransducer catheter as the standard. METHODS: Ninety women without significant pelvic organ prolapse underwent urodynamic evaluations with both fiberoptic and microtransducer catheters. Maximal urethral closure pressures and “leak point pressures” were repeatedly measured by the two catheters and statistically compared. The order of catheter use was randomized. RESULTS: Significantly lower mean maximal urethral closure pressures were recorded by the fiberoptic system than by the microtransducer system (28.9 cmH 2O ± 17.3 versus 43.2 cmH 2O ± 24.9, P < .001). The fiberoptic catheter predicted microtransducer values for maximum urethral closure pressure only within a range of 27 cmH 2O. Mean “leak point pressure” recorded by the fiberoptic catheters (66.9 cmH 2O ± 2.9) was not significantly different than that recorded by the microtransducer catheters (66.4 cmH 2O ± 2.9, P = .97). CONCLUSION: There is a significant difference between maximum urethral closure pressure values recorded by the microtransducer and fiberoptic catheter systems. No significant difference was found between the two systems in measurement of Valsalva “leak point pressure.”

Urodynamic and ultrasonographic evaluation after continence surgery.

Our objective was to evaluate urodynamic and ultrasonographic findings after continence surgery. The study consisted of three groups of women according to the surgery performed: group I (Burch colposuspension) with 12 patients; group II (Kelly-Kennedy plication) with 10 patients; and group III (Gittes surgery) with 9 patients. Urodynamic study was done preoperatively and after surgery (on the 7th and 30th postoperative days, and at least 6 months after surgery) and ultrasonography of the bladder neck was performed to evaluate its position in relation to the inferior edge of the pubic symphysis and its mobility, both preoperatively and after surgery (30th postoperative day). All patients remained continent. We observed an increase in the first desire to void and maximum cystometric capacity after 6 months in groups I and II, respectively. There was no change in the urethral closure pressure profile in the three groups. Elevation of the bladder neck and decrease of its mobility were found by ultrasonography. Urinary continence after surgery is not the result of alterations in the urethral closure pressure profile, but rather of an elevation in the bladder neck and limitation of its mobility, which probably improves the abdominal pressure transmission rate to the proximal urethra.

Clinical, urodynamic, and histologic effects of urethral intussusception in clinically normal dogs

SUMMARY Objective To evaluate clinical and histologic effects of surgically created urethral intussusception and determine whether it creates a high-pressure zone that resists passive urine flow in clinically normal dogs. Animals 8 healthy adult sexually intact female dogs. Procedure Urethral pressure profilometry was used to measure maximal urethral closure pressure (MUCP) and functional profile length (FPL) in dogs sedated with xylazine hydrochloride and atropine before and 2, 4, 7, 14, 28, 60, and 90 days after surgery. Cystourethral leak point pressure (CLPP) and cystourethral leak point volume (CLPV) were determined in anesthetized dogs immediately before and after surgery. Dogs were assigned to 4 groups of 2 dogs each; groups were euthanatized 4, 14, 28, and 90 days later, and representative tissues were examined. Results Dog 1 developed complete postoperative urethral obstruction. The procedure was altered, and all dogs recovered without complication. Mild inflammation attributable to surgical manipulation, but not ischemic damage or reduction of the intussusception, was evident. Comparison of preoperative MUCP and FPL with postoperative values did not yield significant differences. Immediate postoperative CLPP and CLPV were significantly higher than preoperative values, but were not significantly increased at euthanasia. A distinct but nonsignificant pressure spike was observed in postoperative urethral pressure profiles and persisted in 7 of 8 dogs. Conclusions Urethral intussusception does not have deleterious effects when performed as described. Urodynamic data do not support the premise that urethral intussusception will create a high-pressure zone in the urethra that will resist passive urine flow long term in clinically normal dogs. (Am J Vet Res 1998;59:904–912)

Urodynamic changes after radical prostatectomy

Urodynamic examinations were performed in 82 patients with clinically localized prostate cancer before and after radical prostatectomy. A significant decrease in bladder capacity (396 ml to 331.9 ml), urethral closure pressure (89.6 cm H2O to 65.2 cm H2O) and functional profile length (61 mm to 25.9 mm) was noted. The continence rate after radical prostatectomy was 33.4% after 1 month, 69.4% after 3 months, 84.7% after 6 months, and 90.9% after 12 months, respectively. A correlation was found between urethral closure pressure and functional profile length and continence. A second urodynamic examination was performed 6 months after radical prostatectomy. Functional profile length and urethral closure pressure increased. These data suggest that restoration of continence is based on sphincteric parameters.

Urethral closure pressure profiles in the standing position: Are they necessary?

The aim of the study was to assess the sensitivity for urodynamic abnormalities of both static and dynamic urethral closure pressure profiles done in the sitting and standing positions. Multichannel urethral closure pressure profilometry (UCPP) was performed on 21 patients complaining of stress incontinence. Two clinical groups were identified, those with mild to moderate and those with severe incontinence. The parameters of both the static and the dynamic UCPPs obtained in the sitting and standing positions were compared for sensitivity to urodynamic abnormalities. Non-parametric statistical methods were used (Wilcoxon signed rank test; Mann-Whitney test.) No statistically significant differences were found in the mean maximum urethral closure pressures (MUCPs) in the two positions. Patients with a clinical diagnosis of severe incontinence had decreased MUCPs in both positions. It was therefore concluded that the urethral closure pressure profile may be measured in the sitting position without compromising the results.

Transvaginal electrical stimulation in the treatment of genuine stress incontinence and detrusor instability

Electrical stimulation has been widely used in Europe to treat incontinence, but original studies and overall use of the device has been limited in North America. Forty-five patients with documented genuine stress incontinence, detrusor instability or mixed incontinence had self-administered therapy for 15 minutes twice daily, for a duration of 6 weeks. Treatment was delivered by a new stimulation device with an attached vaginal probe. Patients recorded treatment times, leak episodes and pad use. Objective measures included a pad test, standing stress test, standing CMG, and resting and dynamic urethral closure pressure profiles. The subjective success rates based on a questionnaire were 71% for genuine stress incontinence, 70% for detrusor instability, and 52% for combined incontinence. Objective testing for both types of incontinence did not show significant improvement after treatment. Four patients reported pain during use of the device, but most wished to continue the device in preference to other therapy.

Simultaneous recording of urethral pressure and cross sectional area profile.

A new technique for simultaneously recording urethral closure pressure and cross sectional area profile is described. The cross sectional area of the urethra could be measured using the field gradient principle. The procedure was performed readily in male patients and the recordings can be graphically presented during measurement. A high degree of reproducibility using this method was obtained. Typical recordings of control subjects was well as patients with pathology were obtained using this technique. The results of this study show that the maximum urethral closure pressure obtained was 60.8 + 3.4 mmHg and functional profile length, 4.8 + 0.4 cm. Internal meatus cross sectional area was 0.67 + 0.04 cm2 and the minimum urethral cross sectional area was 0.12 + 0.02 cm2. This method has been shown to be readily applicable in measuring urethral closure pressure in males and can potentially be used as a tool of comparing the functional parameters of pressure with the anatomical value of diameter.

Reliability of the Urethral Closure Pressure Profile during Stress in the Diagnosis of Genuine Stress Incontinence

Urethral pressure profile (UPP) measurements were recorded during stress using the method of Brown and Wickham in 981 patients with lower urinary tract symptoms. This procedure was used to identify patients with genuine stress incontinence (GSI). A clinical stress test in the supine and erect position served to confirm urinary leakage. GSI was diagnosed in 661 patients. (67%), whereas no incontinence was demonstrable in 320 (33%). UPP during stress has a high sensitivity (93.3%) and specificity (82.5%). Compared with other urodynamic investigations, the ease with which it can be performed at the same time as other urodynamic procedures makes a reliable diagnostic adjunct in the assessment of patients with GSI.

Neurogenic Bladder in Children: Urodynamic Studies and Results with Medical Conservative Treatment

We present the urodynamic findings and therapeutic results in 25 children with neurogenic bladder, ranging in age from 2 months to 14 years. We observed a significant reduction of urinary infections and vesicoureteral refluxes following medical treatment based on the urodynamic findings. Furthermore, we observed a worse evolution in patients with pre-voiding bladder pressure in excess of 50 cm H2O, incontinence being more difficult to treat in children with urethral closure pressure profile below 47 cm H2O. In our series, anticholinergic treatment improved hypertonia and hyperreflexia which disappeared in 66.6% of cases. Total continence was achieved in 37.5% and improved in 29.1% of children.

The prognostic significance of augmentation of urethral closure pressure and functional length

Sixty-one women with genuine stress incontinence undergoing preoperative and postoperative multichannel urodynamic investigation were tested with augmenting urethral closure pressure profiles during contraction of the pelvic floor muscles to assess voluntary control of the urethral “sphincter.” Increases of 20% or more above resting functional length and closure pressure were selected as indicators of augmentation. The presence or absence of augmentation of functional urethral length and/or closure pressure during pelvic floor contraction allowed for the grouping of these patients into six subgroups which were compared for urinary symptoms, prior anti-incontinence procedures and the presence of low urethral pressure, detrusor instability and genuine stress incontinence both pre- and postoperatively. Evaluation of the patient's ability to augment functional length and closure pressure did not affect surgical success nor did its presence or absence correspond to the presence of a low pressure urethra, detrusor instability, or specific urinary symptoms. Evaluation of augmentation of functional length and closure pressure was therefore felt to be of no prognostic value during the performance of multichannel urodynamic testing in incontinent females.

Simultaneous urethral pressure profilometry using microtip transducer catheters in the bitch: A comparison of catheter material

AbstractSimultaneous urethral pressure profilometry using an 8FG polyurethane microtip transducer catheter in the bitch is subject to considerable variation, Marked differences occur in the parameters normally measured due to the orientation of the transducers and patient position. It has been suggested that a softer catheter may result in less variation. In this study, a comparison was made between 8FG polyurethane and silicone rubber microtip transducer catheters in 35 bitches. There were significant variations in both maximum urethral closure pressure and functional profile length due to catheter type (P &lt; 0–001). Resting intravesical pressure varied with the recording transducer (P &lt; 0–001) and there was a significant interaction between catheter type and recording transducer (P &lt; 0–001). Radiographic measurements on 15 bitches suggested that variations in recorded intravesical pressure were probably related to the location of the transducers of the two catheters within the bladder. It is concluded that the use of a softer catheter material alone is insufficient to eliminate variations resulting from the orientation of the recording sensors within the urethra.