Normal urodynamic parameters in women

Transcription

1 Int Urogynecol J (2012) 23: DOI /s y REVIEW ARTICLE Normal urodynamic parameters in women Part II invasive urodynamics Wally Mahfouz & Tala Al Afraa & Lysanne Campeau & Jacques Corcos Received: 3 May 2011 /Accepted: 6 October 2011 /Published online: 20 October 2011 # The International Urogynecological Association 2011 Abstract Introduction and hypothesis This literature review, providing reference ranges of normal variability in urodynamic parameters, is the second part of a two-part article. The first part addresses non-invasive urodynamics (UDS), while the second part addresses invasive techniques. Methods Data were obtained through MEDLINE from articles published between January 1956 and February 2011, International Continence Society meeting abstracts, and standardization reports. Search terms included cystometry, urethral pressure profilometry, leak point pressure, video UDS, normal volunteer, pressure flow studies, and electromyography. Results Normal values varied widely in the literature. However, with the help of clinical data, it was possible to define normality ranges for most of the different parameters. Conclusions Urodynamic evaluation of lower urinary tract (LUT) function is not a physiological test. However, it is still the best available tool for LUT function assessment. Even if normality in UDS can be defined, tests must always be interpreted against patient characteristics, complaints, and symptoms. Keywords Urodynamics. Normal volunteer. Cystometry. Pressure flow study. Urethral pressure profilometry. Electromyography (EMG) W. Mahfouz : T. Al Afraa : L. Campeau : J. Corcos Department of Urology, Jewish General Hospital, McGill University, Montreal, Quebec, Canada J. Corcos (*) Department of Urology, Jewish General Hospital, 3755 Côte Sainte-Catherine, Montreal, QC H3T 1E2, Canada jcorcos@uro.jgh.mcgill.ca Introduction Non-invasive urodynamics (UDS) consists of tests [voiding diaries, flowmetry, post-void residual (PVR) estimation and pad tests], which do not require any patient manipulation. In contrast, invasive UDS warrants the insertion of catheters, transducers, and/or needle sets into patients. While non-invasive tests are useful tools for screening (i.e., flowmetry) or diagnosis (i.e., voiding diaries), invasive tests are necessary to confirm the diagnosis and refine the findings. The invasiveness of these tests raises the problem of their nonphysiological recording. Acknowledging their limitations, such tests must always be interpreted by an experienced urologist with knowledge of recording conditions and patients complaints and symptoms. Method Data were obtained from various sources, including MEDLINE search via PubMed, for articles published between January 1956 and February 2011, International Continence Society (ICS) meeting abstracts and Standardization Committee reports as well as the bibliographies of retrieved articles and book chapters. The key terms searched were UDS, cystometry, urethral pressure profilometry, leak point pressure, PVR urine, video UDS, normal volunteer, pressure flow studies, and electromyography (EMG). Based on a literature review, we report normal UDS values and ranges in women. Limits Such a review, gathering together results from normal volunteers as well as patients, and trying to define

2 270 Int Urogynecol J (2012) 23: normality have limits. The heterogeneity of the population, the absence of standardized technical methods for some testings, and the frequent absence of gender and age consideration in the interpretation of data, are many limiting factors for such articles. Taking this into consideration, we hope that future research in urodynamics will address this heterogeneity by studying a large cohort of normal volunteers to conform or modify our findings. Cystometry The principal aim of cystometry is to reproduce patient symptoms and relate them to any synchronous urodynamic events [1]. During the filling phase, abdominal and bladder pressures are recorded via rectal and urethral catheters, respectively, whereas detrusor pressure (P det ) is calculated by subtracting abdominal pressure from bladder pressure. Initial resting abdominal and bladder pressures are 5 20 cm H 2 O in the supine position, cm H 2 O in the sitting position, and cm H 2 O in the standing position [2]. P det in an empty bladder varies between 0 and 10 cm H 2 O in 90% of cases [3]. Normal P det during bladder filling at a rate of ml/s should be <20 cm H 2 O[4]. The ICS report 2002 divides the filling rate of the bladder during filling cystometry into: (a) physiological filling rate, which is defined as filling rate less than the predicted maximum predicted maximum body weight in kilogram divided by 4 expressed as milliliter/minute and (b) non-physiological filling rate, which is defined as filling rate greater than the predicted maximum predicted maximum body weight in kilogram divided by 4 expressed as milliliter/minute [5]. Several other parameters are recorded during the filling phase: bladder sensations, bladder compliance, detrusor overactivity (DO), and maximum cystometric capacity (Fig. 1 and Table 1). 1. Bladder sensations Wyndaele et al. studied bladder sensations in 50 normal volunteers (32 female and 18 male) by cystometry. They described three normal bladder sensation patterns: (a) the first sensation of bladder filling, which is felt when the volunteers first become aware of bladder filling (it is vague sensation, felt in the lower pelvis, which waxes and wanes, and could be easily ignored for few minutes); (b) first desire to void, a familial constant sensation that would lead the patient to void in the next convenient moment, but still voiding can be delayed (it is felt in the lower abdomen and gradually increases with bladder filling); and (c) strong desire to void, a persistent desire to void without fear of leakage, and felt in the perineum or urethra. Furthermore, Wyndaele and De Wachter [6] reported that volumes in all three types of sensation were lower in women: The first sensation manifested at 175 ml, the first desire to void was felt at 272 ml, and the strong desire to void presented at 429 ml. 2. Bladder compliance Bladder compliance is the relationship between changes in volume and pressure. It is calculated by dividing change in volume by change in P det and is expressed in milliliter/ centimeter H 2 O[5]. Normal values of bladder compliance have not been well defined. In patients with neurogenic bladder, values of ml/cm H 2 O have been associated with a high risk of upper urinary tract complications [7]. Accordingly, normal bladder compliance values vary between 30 and 100 ml/cm H 2 O. They are higher in women than in men [5, 8 10]. Bladder compliance is considered to be compromised if it is below 30 ml/cm H 2 O [11] (Table 2). Harris et al. [12] studied 270 neurologically intact women and reported that normal bladder compliance was >40 ml/cm H 2 O. Wyndaele [10] conducted a urodynamic study of 30 volunteers (20 male and 10 female volunteers), and found that compliance was higher in female than in male volunteers, with normality exceeding 100 ml/cm H 2 O. The ICS [5] recommends two standard points for measuring bladder compliance: detrusor pressure at empty bladder and at maximum bladder capacity or immediately before the start of any detrusor contraction that causes significant leakage. Both points are measured excluding any detrusor contraction. Wahl et al. [13, 14] developed another method for measuring bladder compliance that they claimed was more accurate and practical, especially in children. They standardized bladder compliance according to a complex mathematical formula. 3. Detrusor stability during bladder filling The absence of involuntary detrusor contractions is considered to be normal and is defined as stable detrusor activity [10, 15]. Uninhibited detrusor contractions occur in 10 18% of asymptomatic volunteers and do not need any further evaluation in asymptomatic patients [10, 16]. Advance in ambulatory UDS has complicated discussion of DO, which has been shown to arise in 60% of asymptomatic women undergoing ambulatory UDS [17]. The significance of these DO in normal volunteers is not very well understood as shown by the study looking for correlation with other variables in this population. The mere absence of documented overactivity on cystometrograms (CMG) does not rule out its existence. Up to 40% of patients with urge incontinence do not show DO on CMG [18]. The 1988 ICS report [8] differentiated types of detrusor storage function, as determined by filling cystometry, into:

3 Int Urogynecol J (2012) 23: Fig. 1 The normal cystometrogram curve has two phases: a filling phase, including all normal parameters during the storage phase (first sensation, detrusor function, bladder compliance, and capacity) and a voiding phase on pressure flow study (a) normal detrusor function, which allows filling with little or no change in pressure and no involuntary phasic contractions despite provocation, and (b) overactive detrusor function, which is urodynamic observation characterized by involuntary detrusor contractions during the filling phase and may be spontaneous or provoked [19]. DO has a variety of patterns on urodynamic tracing. The 2002 ICS report [5] describes two types: (a) phasic DO, defined by its characteristic waveform, which may or may not lead to urinary incontinence, and (b) terminal DO, classified as a single involuntary detrusor contraction occurring at cystometric capacity, which cannot be suppressed and causes incontinence often resulting in complete bladder emptying [17]. The first ICS report [20, 21] stated that, in order to diagnose detrusor instability, the contraction should be at least 15 cm H 2 O. However, it was subsequently realized that involuntary detrusor contractions of <15 cm H 2 O could cause significant symptoms. The ICS [5, 8] stated that there is no standardized minimum value. In practice, it may be difficult to be certain whether an involuntary detrusor contraction has occurred if the phasic wave is <5 cm H 2 O[17]. 4. Maximum cystometric bladder capacity Maximum cystometric capacity is the bladder volume at the end of filling CMG when patients have a strong desire to void, feel they can no longer delay micturition, and are Table 1 Normal reported cystometric parameters during filling in females Parameter Wyndaele [10, 49] Pfisterer et al. [43] Normal range Number of volunteers 38 (28 men and 10 women) 24 (women) Mean age (years) First sensation (ml) First desire to void (ml) Strong desire to void (ml) Bladder compliance (ml/cm H 2 O) Detrusor activity Stable Stable Maximum cystometric capacity (ml)

4 272 Int Urogynecol J (2012) 23: Table 2 Normal bladder compliance (reproduced with permission from Corcos and Schick [50]) Definition Comment Compliance index [51] Normal= (with bladder capacity >650 ml) Volume (in ml)/detrusor pressure (in cm H 2 O) at bladder capacity Compliance [52] Normal=30 55 Volume in ml/1 cm H 2 O Capacity= ml Compliance [53] Normal 10 cm H 2 O/100 ml Low >10 given permission to void [5]. This volume includes both the amount voided and residual urine left after the void (PVR) [17]. Normal cystometric capacity varies widely, but is normally between 300 and 500 ml, with higher values in men than in women [10]. Wyndaele [10] conducted a urodynamic study of 30 volunteers (20 male and 10 female), with a mean age of 24 years, and reported wide variability of normal ranges. Bladder capacity was found to be larger in men than in women, ranging from 300 to 550 ml. The bladder should have constantly low pressure that usually does not reach more than 6 10 cm H 2 O above baseline at the end of filling (end-filling pressure), and there should be no involuntary contractions, with normal first sensation ranging between 100 and 250 ml, bladder compliance between 30 and 100 ml/cm H 2 O, and maximum bladder capacity between 450 and 550 ml. Pressure flow (P/Q) P/Q study simultaneously measures P det and flow rate during voiding. P/Q assessment is considered to be the gold standard for quantifying and grading bladder outlet obstruction (BOO) and differentiating between BOO and detrusor underactivity [22 28]. P/Q data can be plotted on pressure flow nomograms to classify patients as being either obstructed or not obstructed and, at the same time, grade the severity of obstruction. Different types of nomograms have been developed. The most common in clinical practice are ICS nomogram [22], Abrams Griffiths nomogram, Schafer nomogram, bladder contractility nomogram, urethral resistance factor, and the composite nomogram [17], but these nomograms are used in men only. During P/Q assessment, several parameters are recorded, including detrusor opening pressure, maximum detrusor pressure (P det.max ), P det at maximum flow (P det :Qmax ), minimum detrusor pressure during voiding, maximum flow rate (Q max ), voided volume (VV), and PVR. The ICS has defined the following terms in the interpretation of P/Q [3, 5]. Pre-micturition pressure is intravesical pressure just before the onset of isovolumetric detrusor contraction. Detrusor opening pressure is P det recorded at the onset of measured flow, which tends to be elevated in patients with infravesical obstruction. Opening time is the time that elapses from the initial rise in P det to the onset of flow through the urethra. However, because flow rate is measured at a downstream location (i.e., flowmeter outside the urethra), flow rate measurement is slightly delayed from bladder pressure measurement. This flow delay, generally between 0.5 and 1 s, should be factored into the analysis [29]. P det :Qmax is the magnitude of detrusor contraction when flow rate is at its maximum [5]. P det.max is the maximal pressure recorded regardless of flow. This pressure can exceed pressure at maximal flow if the bladder is contracting isometrically against a closed outlet. Isometric detrusor pressure is obtained by mechanical obstruction of the urethra or by active contraction of the distal sphincter mechanism during voiding. Post-micturition contraction (after contraction) is a reiteration of detrusor contraction after flow has ceased, and its magnitude is typically greater than that of micturition pressure at maximal flow. After contractions are not well-understood, but they seem to be more common in patients with unstable or hypersensitive bladders [30]. PVR is the volume of urine remaining in the bladder immediately after voiding. Although the test situation often leads to inefficient voiding and falsely elevated residual urine, the absence of residual urine does not exclude infravesical obstruction or bladder dysfunction [17]. Wyndaele [10] attempted to define what can be considered as normal parameters by urodynamics in 38 healthy adult volunteers (28 men and 10 women) with a mean age of 24 years. Free flow rate, water cystometry, and P/Q assessment were performed in all of them. Micturition bladder pressure was higher in men than in women, reflecting higher outflow resistance in men, but P det was not statistically different between the sexes. Flow time was significantly longer, and Q max was significantly lower during P/Q evaluation than during free flow rate measurement in both sexes. There was no residual urine at all in the

5 Int Urogynecol J (2012) 23: majority of volunteers estimated by urethral catheter, but six men and three women had <50 ml residual urine. Pressure flow (P/Q) studies (Table 3) Blaivas and Groutz studied 50 women with BOO (mean age, 65 years) and 20 normal controls (mean age, 67 years) by videourodynamics (VUDS) assessment [31]. The P/Q parameters recorded in the control group were: free Q max of 24±9 ml/s, Q max of 13±6 ml/s, P det :Qmax of 18±8 cm H 2 O, P det.max of 22±9 cm H 2 O, VV of 312±131 ml, and PVR of 103±100 ml. These authors described a nomogram to diagnose BOO in women, known as Blaivas nomogram (Fig. 2). Two parameters are needed to construct this nomogram: free Q max and P det.max. Free Q max is preferred to Q max during P/Q because P det :Qmax and Q max cannot be evaluated if the patient does not void during the test. Blaivas nomogram consists of four zones, which classify patients into four categories: zone 0 (normal or no obstruction), zone 1 (mild obstruction), zone 2 (moderate obstruction), and zone 3 (severe obstruction) [31]. Defreitas et al. [32] investigated 169 women with BOO and 20 asymptomatic volunteers by P/Q assessment. They reported normal Q max and P det :Qmax as 16 ml/s and 24 cm H 2 O, respectively, in the asymptomatic group. The cut-off values to detect BOO with P det :Qmax and Q max were 25 cm H 2 O and 12 ml/s, respectively, with sensitivity, specificity, and accuracy of 68%. Chassagne et al. [33] mentioned that the combined cut-off values for diagnosing BOO in women are Q max <15 ml/s and P det :Qmax >20 cm H 2 O, yielding sensitivity of 74.3% and specificity of 91.1%. Brostrom et al. [34] performed a P/Q study in 30 normal female volunteers with a mean age of 52 years. Two sets of measurements were recorded. They found that, between two repeated measurements, there was a statistically Fig. 2 Bladder outlet obstruction nomogram (Blavias nomogram) for women indicating that normal women should be in an area of no obstruction (grade 0) significant increase in first desire to void (171 and 205 ml) and a normal desire to void (284 and 351 ml) with a decrease in bladder opening pressure, whereas no change was noted in maximum cystometric capacity (572 and 570 ml). Kuo [35] investigated 441 women with BOO and stress urinary incontinence (SUI) as well as 30 asymptomatic volunteers. He reported that P det :Qmax 30 cm H 2 OcombinedwithQ max 15 ml/s indicated BOO with specificity of 93.9% and sensitivity of 81.6%. In asymptomatic females, Q max ranges from 13 to 25 ml/s, P det :Qmax ranges from 18 to 30 cm H 2 O, P det.max ranges from 22 to 46 cm H 2 O and VV ranges between 250 and 650 ml. Leak point pressures 1. Detrusor leak point pressure Detrusor leak point pressure (DLPP) is defined by the ICS as the lowest P det at which urine leakage occurs in the absence of either detrusor contraction or increased abdominal pressure [5]. The rise in bladder pressure is secondary to low bladder compliance. This value reflects resistance that the urethra offers to the bladder, mainly by the action of the striated sphincter [17, 36]. In patients with neurogenic bladder, a high DLPP can jeopardize upper urinary tract function. McGuire et al. [37] followed the urodynamic evolution of 42 myelodysplastic children and observed that those with DLPP 40 cm H 2 O developed upper tract damage if not treated. 2. Abdominal leak point pressure or Valsalva leak point pressure Abdominal leak point pressure (ALPP) or valsalva leak point pressure (VLPP) is intravesical pressure at which urine leakage occurs because of increased abdominal pressure in the absence of detrusor contraction [5]. It measures the ability of the urethra to resist an increase in abdominal pressure. ALPP should be tested during cystometry after the bladder has been filled to at least ml. The patient is then asked to do a valsalva maneuver until he or she leaks. VLPP is the lowest pressure at which incontinence occurs [17]. This test assesses the severity of SUI and may be useful in detecting intrinsic sphincter deficiency (ISD). In normal individuals, no incontinence should be recorded, whatever the increase in abdominal pressure. Therefore, there is no normal ALPP. However, studies have attempted to determine a cut-off between patients with or without ISD [17].

6 274 Int Urogynecol J (2012) 23: Table 3 Normal reported P/Q parameters in women Brostrom et al. [34] Blaivas and Groutz [31] Pfisterer et al. [43] Defreitas et al. [32] Chassagne et al. [33] Normal range Number of patients 30 female volunteers 50 female volunteers 24 female volunteers 20 female volunteers 124 unobstructed women Mean age (years) Q max (ml/s) Q ave (ml/s) TQ (s) P det.open (cm H 2 O) P det :Qmax (cm H 2 O) P det.max (cm H 2 O) VV (ml) Q max maximum flow rate, Q ave average flow rate, TQ flow time, P det.open opening detrusor pressure, P det :Qmax detrusor pressure at maximum flow; P det.max maximum detrusor pressure during voiding McGuire et al. [38] employed VUDS and demonstrated that 80% of women with VLPP below 60 cm H 2 O had type III SUI. They also showed that VLPP values above 90 cm H 2 O could rule out ISD. In fact, in women suffering from SUI without genital prolapse, high ALPP of 100 cm H 2 Oor more is usually associated with urethral hypermobility. Those with values between 60 and 100 cm H 2 O have features of both ISD and hypermobility [39]. There should be no DLPP in normal individuals. In neurogenic patients, DLPP higher than or equal to 40 cm H 2 O is considered dangerous for the upper tract. In normal individuals, no abdominal pressure increase should cause incontinence. Therefore, there is no limit of normal ALPP. In women with SUI, VLPP below 60 cm H 2 O is highly suggestive of ISD. VLPP of 100 cm H 2 O or more is usually associated with urethral hypermobility. Values between 60 and 100 cm H 2 O are suggestive of both ISD and hypermobility. Urethral pressure profilometry Urethral pressure is defined by the ICS as the fluid pressure needed to just open a closed urethra [5], and the urethral pressure profilometry (UPP) is a graph indicating changes in intraluminal pressure along the length of the urethra. UPP quantifies the occlusive pressure generated by active and passive structures of the urethra and allows the evaluation of urethral competence. Two variations of this measurement are commonly reported: static UPP, with its variants stress UPP and pressure transmission ratios, and micturitional UPP [17]. Maximum urethral pressure (MUP) is categorized as maximum pressure of the measured profile, while maximum urethral closure pressure (MUCP) is defined as the maximum difference between urethral pressure and intravesical pressure. UPP rises in normal healthy individuals with increasing bladder volume. It is the so-called guarding reflex. However, continuous recording of MUP shows variations and oscillations between 10 and 25 cm H 2 O[40]. MUCP below 20 cm H 2 O is considered hypotonic, raising the possibility of ISD. MUCP values above 75 cm H 2 O in women and 90 cm H 2 O in men are considered hypertonic [17]. Sorensen et al. [41] analyzed urethral pressure variations in 10 healthy, fertile female volunteers (mean age, 32 years) and 12 healthy post-menopausal volunteers (mean age, 58.7 years). In the fertile group, they observed that mean maximum urethral pressure (mmup) and mean maximum urethral closure pressure (mmucp) had median values of 66.5 and 60 cm H 2 O, respectively. Postmenopausal women had significantly lower mmup and mmucp: 55.5 and 43.5 cm H 2 O, respectively. Van Geelen et al. [42] studied 27 nulliparous healthy women between the ages of 19 and 35 years and recorded mmup of 98±17 cm H 2 Oin the supine position, with mean MUCP of 84±18 cm H 2 O. Pfisterer et al. [43] examined bladder function parameters in pre-, peri-, and postmenopausal, continent women, discerning mmucp of 94, 74, and 42 cm H 2 O, with functional urethral lengths of 3.3, 3.3, and 3.5 cm, respectively. It is desirable that the urethral catheter is perfused at a constant rate. This necessitates the use of a motorized syringe pump or a very accurate peristaltic pump. A perfusion rate of between 2 and 10 ml/min gives an accurate measurement of closure pressure. Perfusion rates of <2 ml/min usually fail to record the true urethral pressure unless the withdrawal rate is extremely slow [1].

7 Int Urogynecol J (2012) 23: Stress UPP measures the rise in intra-abdominal pressure transmitted to the proximal urethra. In normal women without urethral hypermobility, increases in intravesical pressure and proximal urethral pressure should be similar. The pressure transmission ratio is a different parameter, recording the increment of urethral pressure with stress as a percentage of intravesical pressure elevation. In normal women, this value should exceed 100 cm H 2 O[44]. Micturitional UPP serves to identify the presence and location of BOO [45]. It is performed in a manner similar to static UPP except that the patient voids as the catheter is being withdrawn. This allows bladder pressure to be compared with urethral pressure at points along the urethra. If a significant drop is encountered on catheter withdrawal, it corresponds to the site of obstruction. MUCP below 20 cm H 2 O raises the possibility of ISD. MUCP values above 75 cm H 2 O for women are considered hypertonic [17]. Electromyography of the pelvic floor and external urethral sphincter Clinical neurophysiological studies, which include sphincter EMG, record bioelectric potentials generated during muscle depolarization. They enable clinicians to completely evaluate the striated sphincter complex and pelvic floor activity during bladder filling, storage, and voiding. Clinically, the most important information obtained from sphincter EMG is coordination or discoordination between the external urethral sphincter (EUS) and the bladder [17]. EMG is undertaken with electrodes. The needle is placed lateral to the urethral meatus and is advanced parallel to the urethra to a distance of about 1 2 cm. For representative EMG studies of the perineal floor, needle and wire electrodes may be placed in the superficial anal sphincter in women [17]. Kinesiologic investigations may be performed with a variety of electrodes and display methods. Needle/wire electrodes are preferable because they are positioned in the muscle of interest, allowing the detection of activity in individual motor units [17]. Normally, EMG activity from the EUS is low at rest. It intensifies as fluid volume in the bladder grows, during bladder filling, due to EUS contraction. It is known as the guarding reflex. During voiding, EMG activity disappears completely for a few seconds before detrusor contraction starts. Once the bladder is empty, EMG activity resumes [46, 47]. Failure of the sphincter to relax or stay completely relaxed during micturition is abnormal [5]. When it occurs in patients with neurologic disease, it is termed detrusor sphincter dyssynergia; it is typical in patients with suprasacral spinal cord injury. The term detrusor sphincter dyssynergia cannot be used in the absence of neurologic disease. Instead, the applicable term is pelvic floor hyperactivity or dysfunctional voiding [17]. EMG activity increases progressively during bladder filling. The rise in EMG activity during heightened abdominal pressure (cough, straining, etc.) is proportional to the level of stress. EMG activity of the external sphincter and pelvic muscles should be silent during voiding. Reproducibility of urodynamics in healthy women Reliability and reproducibility of different urodynamic procedures are questionable. Short-term reproducibility (same session or duplicate) was studied in several reports [34, 48]. An increase in first and normal desires on second fill was noted, yet maximum cystometric capacity reamined unchanged. Conclusions Urodynamic tests are useful tools to evaluate LUT dysfunction. They are gold standards for the diagnosis of BOO and urinary incontinence. Urodynamic evaluation is a good predictor of outcomes after therapeutic intervention. Urodynamic normality in healthy populations is not well known and illustrates a wide variety of data and patterns. Several important parameters, such as age, sex, and body mass index, affect urodynamic values, rendering it more challenging to precisely define normality from tests performed on patients. Mathematical models and simulation may help in the future to generate more data on normality, but additional studies on healthy volunteers must be encouraged to gather more information. Conflicts of interest References None. 1. Abrams P (ed) (2006) Urodynamics. Springer, Singapore 2. Chapple CR, MacDiarmid S, Patel A (eds) (2009) Urodynamics made easy. Churchill Livingstone/Elsevier, Barcelona 3. Schafer W, Abrams P, Liao L, Mattiasson A, Pesce F, Spangberg A, Sterling AM, Zinner NR, van Kerrebroeck P (2002) Good urodynamic practices: uroflowmetry, filling cystometry, and pressure-flow studies. Neurourol Urodyn 21:

8 276 Int Urogynecol J (2012) 23: Abrams PH, Dunn M, George N (1978) Urodynamic findings in chronic retention of urine and their relevance to results of surgery. Br Med J 2: Abrams P, Cardozo L, Fall M, Griffiths D, Rosier P, Ulmsten U, van Kerrebroeck P, Victor A, Wein A (2002) The standardisation of terminology of lower urinary tract function: report from the Standardisation Sub-committee of the International Continence Society. Neurourol Urodyn 21: Wyndaele JJ, De Wachter S (2002) Cystometrical sensory data from a normal population: comparison of two groups of young healthy volunteers examined with 5 years interval. Eur Urol 42: Blaivas JG, Chancellor M, Weiss J, Verhaaren M (eds) (2007) Atlas of urodynamics. Blackwell, Milton 8. Abrams P, Blaivas JG, Stanton SL, Andersen JT (1988) The standardisation of terminology of lower urinary tract function. The International Continence Society Committee on Standardisation of Terminology. Scand J Urol Nephrol Suppl 114: Bates P, Bradley WE, Glen E, Melchior H, Rowan D, Sterling A, Hald T (1976) The standardization of terminology of lower urinary tract function. Eur Urol 2: Wyndaele JJ (1999) Normality in urodynamics studied in healthy adults. J Urol 161: Sullivan MP, Yalla SV (1996) Detrusor contractility and compliance characteristics in adult male patients with obstructive and nonobstructive voiding dysfunction. J Urol 155: Harris RL, Cundiff GW, Theofrastous JP, Bump RC (1996) Bladder compliance in neurologically intact women. Neurourol Urodyn 15: Wahl EF, Lerman SE, Lahdes-Vasama TT, Churchill BM (2004) Measurement of bladder compliance can be standardized by a dimensionless number: clinical perspective. BJU Int 94: Wahl EF, Lerman SE, Lahdes-Vasama TT, Churchill BM (2004) Measurement of bladder compliance can be standardized by a dimensionless number: theoretical perspective. BJU Int 94: Pauwels E, De Wachter S, Wyndaele JJ (2004) Normality of bladder filling studied in symptom-free middle-aged women. J Urol 171: Ouslander J, Leach G, Abelson S, Staskin D, Blaustein J, Raz S (1988) Simple versus multichannel cystometry in the evaluation of bladder function in an incontinent geriatric population. J Urol 140: Peterson A, Webster G (eds) (2007) Urodynamic and videourodynamic evaluation of voiding dysfunction. Saunders, Philadelphia 18. McGuire EJ (1995) Urodynamic evaluation of stress incontinence. Urol Clin N Am 22: Abrams P, Andersson KE, Birder L, Brubaker L, Cardozo L, Chapple C, Cottenden A, Davila W, de Ridder D, Dmochowski R, Drake M, Dubeau C, Fry C, Hanno P, Smith JH, Herschorn S, Hosker G, Kelleher C, Koelbl H, Khoury S, Madoff R, Milsom I, Moore K, Newman D, Nitti V, Norton C, Nygaard I, Payne C, Smith A, Staskin D, Tekgul S, Thuroff J, Tubaro A, Vodusek D, Wein A, Wyndaele JJ (2010) Fourth International Consultation on Incontinence Recommendations of the International Scientific Committee: evaluation and treatment of urinary incontinence, pelvic organ prolapse, and fecal incontinence. Neurourol Urodyn 29: Bates CP, Bradley WE, Glen ES, Griffiths D, Melchior H, Rowan D, Sterling A, Hald T (1980) Third report on the standardisation of terminology of lower urinary tract function procedures related to the evaluation of micturition: pressure flow relationships. Residual urine. Produced by the International Continence Society, February Br J Urol 52: Bates CP, Bradley WE, Glen ES, Griffiths D, Melchior H, Rowan D, Sterling A, Hald T (1980) Third report on the standardisation of terminology of lower urinary tract function. Procedures related to the evaluation of micturition, pressure flow relationships, residual urine. Produced by the International Continence Society Committee on Standardisation of Terminology, Nottingham, February Eur Urol 6: Abrams P (1999) Bladder outlet obstruction index, bladder contractility index and bladder voiding efficiency: three simple indices to define bladder voiding function. BJU Int 84: Abrams P, Torrens M (1979) Urine flow studies. Urol Clin N Am 6: Lim CS, Abrams P (1995) The Abrams Griffiths nomogram. World J Urol 13: Schafer W (1995) Analysis of bladder-outlet function with the linearized passive urethral resistance relation, linpurr, and a disease-specific approach for grading obstruction: from complex to simple. World J Urol 13: Eri LM, Wessel N, Tysland O, Berge V (2002) Comparative study of pressure-flow parameters. Neurourol Urodyn 21: Griffiths DJ (1996) Pressure-flow studies of micturition. Urol Clin North Am 23: Dietz HP, Haylen BT, Vancaillie TG (2002) Female pelvic organ prolapse and voiding function. Int Urogynecol J Pelvic Floor Dysfunct 13: Griffiths D, Hofner K, van Mastrigt R, Rollema HJ, Spangberg A, Gleason D (1997) Standardization of terminology of lower urinary tract function: pressure-flow studies of voiding, urethral resistance, and urethral obstruction. International Continence Society Subcommittee on Standardization of Terminology of Pressure- Flow Studies. Neurourol Urodyn 16: Webster G, Koefoot R (1983) The after contraction in urodynamic micturition studies. Neurourol Urodyn 2: Blaivas JG, Groutz A (2000) Bladder outlet obstruction nomogram for women with lower urinary tract symptomatology. Neurourol Urodyn 19: Defreitas GA, Zimmern PE, Lemack GE, Shariat SF (2004) Refining diagnosis of anatomic female bladder outlet obstruction: comparison of pressure-flow study parameters in clinically obstructed women with those of normal controls. Urology 64: , discussion Chassagne S, Bernier PA, Haab F, Roehrborn CG, Reisch JS, Zimmern PE (1998) Proposed cutoff values to define bladder outlet obstruction in women. Urology 51: Brostrom S, Jennum P, Lose G (2002) Short-term reproducibility of cystometry and pressure-flow micturition studies in healthy women. Neurourol Urodyn 21: Kuo HC (2004) Urodynamic parameters for the diagnosis of bladder outlet obstruction in women. Urol Int 72: Lane TM, Shah PJ (2000) Leak-point pressures. BJU Int 86: McGuire EJ, Woodside JR, Borden TA, Weiss RM (1981) Prognostic value of urodynamic testing in myelodysplastic patients. J Urol 126: McGuire EJ, Fitzpatrick CC, Wan J, Bloom D, Sanvordenker J, Ritchey M, Gormley EA (1993) Clinical assessment of urethral sphincter function. J Urol 150: McGuire EJ, Cespedes RD, O Connell HE (1996) Leak-point pressures. Urol Clin North Am 23: Corcos J, Schick E (eds) (2001) The urinary sphincter. Marcel Dekker, New York 41. Sorensen S, Waechter PB, Constantinou CE, Kirkeby HJ, Jonler M, Djurhuus JC (1991) Urethral pressure and pressure variations in healthy fertile and postmenopausal women with reference to the female sex hormones. J Urol 146: Van Geelen JM, Doesburg WH, Thomas CM, Martin CB Jr (1981) Urodynamic studies in the normal menstrual cycle: the relationship between hormonal changes during the menstrual

9 Int Urogynecol J (2012) 23: cycle and the urethral pressure profile. Am J Obstet Gynecol 141: Pfisterer MH, Griffiths DJ, Rosenberg L, Schaefer W, Resnick NM (2007) Parameters of bladder function in pre-, peri-, and postmenopausal continent women without detrusor overactivity. Neurourol Urodyn 26: Nitti V (ed) (1998) Practical urodynamics. WB Sanders, Philadelphia 45. Yalla SV, Sharma GV, Barsamian EM (1980) Micturitional static urethral pressure profile: a method of recording urethral pressure profile during voiding and the implications. J Urol 124: Blaivas JG, Sinha HP, Zayed AA, Labib KB (1981) Detrusorexternal sphincter dyssynergia: a detailed electromyographic study. J Urol 125: O Donnell P, Beck C, Doyle R, Eubanks C (1988) Surface electrodes in perineal electromyography. Urology 32: Sorensen SS, Nielsen JB, Norgaard JP, Knudsen LM, Djurhuus JC (1984) Changes in bladder volumes with repetition of water cystometry. Urol Res 12: Wyndaele JJ (1998) The normal pattern of perception of bladder filling during cystometry studied in 38 young healthy volunteers. J Urol 160: Corcos J, Schick E (eds) (1996) Les vessies neurogènes de l adulte. Masson, Paris 51. Wall L, Norton P, De Lancey J (eds) (1993) Practical urogynecology. Williams and Wilkins, Baltimore 52. Mundy A, Stephenson T, Wein J (eds) (1984) Urodynamics. Principles, practice and application. Churchill Livingstone, Edinburgh 53. Krane R, Siroky M (eds) (1991) Clinical neurourology. Little Brown & Co, Boston